diff --git a/.gitmodules b/.gitmodules new file mode 100644 index 00000000..5e37d17b --- /dev/null +++ b/.gitmodules @@ -0,0 +1,3 @@ +[submodule "third_party/lodepng"] + path = third_party/lodepng + url = https://github.com/lvandeve/lodepng diff --git a/desktop_version/CMakeLists.txt b/desktop_version/CMakeLists.txt index 636b72b4..ce40d1a0 100644 --- a/desktop_version/CMakeLists.txt +++ b/desktop_version/CMakeLists.txt @@ -185,7 +185,7 @@ if(APPLE) # Are you noticing a pattern with this Apple crap yet? set(PFS_SRC ${PFS_SRC} ../third_party/physfs/physfs_platform_apple.m) endif() -set(PNG_SRC ../third_party/lodepng/lodepng.c) +set(PNG_SRC src/lodepng_wrapper.c) if(NOT OFFICIAL_BUILD) # Add interim commit hash and its date to the build diff --git a/desktop_version/src/lodepng_wrapper.c b/desktop_version/src/lodepng_wrapper.c new file mode 100644 index 00000000..a2cbb9b3 --- /dev/null +++ b/desktop_version/src/lodepng_wrapper.c @@ -0,0 +1,2 @@ +/* Workaround for being unable to rename lodepng.cpp to lodepng.c */ +#include "../../third_party/lodepng/lodepng.cpp" diff --git a/third_party/lodepng b/third_party/lodepng new file mode 160000 index 00000000..5601b827 --- /dev/null +++ b/third_party/lodepng @@ -0,0 +1 @@ +Subproject commit 5601b8272a6850b7c5d693dd0c0e16da50be8d8d diff --git a/third_party/lodepng/LICENSE.txt b/third_party/lodepng/LICENSE.txt deleted file mode 100644 index a5fb0603..00000000 --- a/third_party/lodepng/LICENSE.txt +++ /dev/null @@ -1,21 +0,0 @@ -Copyright (c) 2005-2018 Lode Vandevenne - -This software is provided 'as-is', without any express or implied -warranty. In no event will the authors be held liable for any damages -arising from the use of this software. - -Permission is granted to anyone to use this software for any purpose, -including commercial applications, and to alter it and redistribute it -freely, subject to the following restrictions: - - 1. The origin of this software must not be misrepresented; you must not - claim that you wrote the original software. If you use this software - in a product, an acknowledgment in the product documentation would be - appreciated but is not required. - - 2. Altered source versions must be plainly marked as such, and must not be - misrepresented as being the original software. - - 3. This notice may not be removed or altered from any source - distribution. - diff --git a/third_party/lodepng/lodepng.c b/third_party/lodepng/lodepng.c deleted file mode 100644 index a396be0b..00000000 --- a/third_party/lodepng/lodepng.c +++ /dev/null @@ -1,6488 +0,0 @@ -/* -LodePNG version 20220109 - -Copyright (c) 2005-2022 Lode Vandevenne - -This software is provided 'as-is', without any express or implied -warranty. In no event will the authors be held liable for any damages -arising from the use of this software. - -Permission is granted to anyone to use this software for any purpose, -including commercial applications, and to alter it and redistribute it -freely, subject to the following restrictions: - - 1. The origin of this software must not be misrepresented; you must not - claim that you wrote the original software. If you use this software - in a product, an acknowledgment in the product documentation would be - appreciated but is not required. - - 2. Altered source versions must be plainly marked as such, and must not be - misrepresented as being the original software. - - 3. This notice may not be removed or altered from any source - distribution. -*/ - -/* -The manual and changelog are in the header file "lodepng.h" -Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C. -*/ - -#include "lodepng.h" - -#ifdef LODEPNG_COMPILE_DISK -#include /* LONG_MAX */ -#include /* file handling */ -#endif /* LODEPNG_COMPILE_DISK */ - -#ifdef LODEPNG_COMPILE_ALLOCATORS -#include /* allocations */ -#endif /* LODEPNG_COMPILE_ALLOCATORS */ - -#if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/ -#pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/ -#pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/ -#endif /*_MSC_VER */ - -const char* LODEPNG_VERSION_STRING = "20220109"; - -/* -This source file is built up in the following large parts. The code sections -with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way. --Tools for C and common code for PNG and Zlib --C Code for Zlib (huffman, deflate, ...) --C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...) --The C++ wrapper around all of the above -*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* // Tools for C, and common code for PNG and Zlib. // */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ - -/*The malloc, realloc and free functions defined here with "lodepng_" in front -of the name, so that you can easily change them to others related to your -platform if needed. Everything else in the code calls these. Pass --DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out -#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and -define them in your own project's source files without needing to change -lodepng source code. Don't forget to remove "static" if you copypaste them -from here.*/ - -#ifdef LODEPNG_COMPILE_ALLOCATORS -static void* lodepng_malloc(size_t size) { -#ifdef LODEPNG_MAX_ALLOC - if(size > LODEPNG_MAX_ALLOC) return 0; -#endif - return malloc(size); -} - -/* NOTE: when realloc returns NULL, it leaves the original memory untouched */ -static void* lodepng_realloc(void* ptr, size_t new_size) { -#ifdef LODEPNG_MAX_ALLOC - if(new_size > LODEPNG_MAX_ALLOC) return 0; -#endif - return realloc(ptr, new_size); -} - -static void lodepng_free(void* ptr) { - free(ptr); -} -#else /*LODEPNG_COMPILE_ALLOCATORS*/ -/* TODO: support giving additional void* payload to the custom allocators */ -void* lodepng_malloc(size_t size); -void* lodepng_realloc(void* ptr, size_t new_size); -void lodepng_free(void* ptr); -#endif /*LODEPNG_COMPILE_ALLOCATORS*/ - -/* convince the compiler to inline a function, for use when this measurably improves performance */ -/* inline is not available in C90, but use it when supported by the compiler */ -#if (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)) || (defined(__cplusplus) && (__cplusplus >= 199711L)) -#define LODEPNG_INLINE inline -#else -#define LODEPNG_INLINE /* not available */ -#endif - -/* restrict is not available in C90, but use it when supported by the compiler */ -#if (defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))) ||\ - (defined(_MSC_VER) && (_MSC_VER >= 1400)) || \ - (defined(__WATCOMC__) && (__WATCOMC__ >= 1250) && !defined(__cplusplus)) -#define LODEPNG_RESTRICT __restrict -#else -#define LODEPNG_RESTRICT /* not available */ -#endif - -/* Replacements for C library functions such as memcpy and strlen, to support platforms -where a full C library is not available. The compiler can recognize them and compile -to something as fast. */ - -static void lodepng_memcpy(void* LODEPNG_RESTRICT dst, - const void* LODEPNG_RESTRICT src, size_t size) { - size_t i; - for(i = 0; i < size; i++) ((char*)dst)[i] = ((const char*)src)[i]; -} - -static void lodepng_memset(void* LODEPNG_RESTRICT dst, - int value, size_t num) { - size_t i; - for(i = 0; i < num; i++) ((char*)dst)[i] = (char)value; -} - -/* does not check memory out of bounds, do not use on untrusted data */ -static size_t lodepng_strlen(const char* a) { - const char* orig = a; - /* avoid warning about unused function in case of disabled COMPILE... macros */ - (void)(&lodepng_strlen); - while(*a) a++; - return (size_t)(a - orig); -} - -#define LODEPNG_MAX(a, b) (((a) > (b)) ? (a) : (b)) -#define LODEPNG_MIN(a, b) (((a) < (b)) ? (a) : (b)) -#define LODEPNG_ABS(x) ((x) < 0 ? -(x) : (x)) - -#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER) -/* Safely check if adding two integers will overflow (no undefined -behavior, compiler removing the code, etc...) and output result. */ -static int lodepng_addofl(size_t a, size_t b, size_t* result) { - *result = a + b; /* Unsigned addition is well defined and safe in C90 */ - return *result < a; -} -#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_DECODER)*/ - -#ifdef LODEPNG_COMPILE_DECODER -/* Safely check if multiplying two integers will overflow (no undefined -behavior, compiler removing the code, etc...) and output result. */ -static int lodepng_mulofl(size_t a, size_t b, size_t* result) { - *result = a * b; /* Unsigned multiplication is well defined and safe in C90 */ - return (a != 0 && *result / a != b); -} - -#ifdef LODEPNG_COMPILE_ZLIB -/* Safely check if a + b > c, even if overflow could happen. */ -static int lodepng_gtofl(size_t a, size_t b, size_t c) { - size_t d; - if(lodepng_addofl(a, b, &d)) return 1; - return d > c; -} -#endif /*LODEPNG_COMPILE_ZLIB*/ -#endif /*LODEPNG_COMPILE_DECODER*/ - - -/* -Often in case of an error a value is assigned to a variable and then it breaks -out of a loop (to go to the cleanup phase of a function). This macro does that. -It makes the error handling code shorter and more readable. - -Example: if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83); -*/ -#define CERROR_BREAK(errorvar, code){\ - errorvar = code;\ - break;\ -} - -/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/ -#define ERROR_BREAK(code) CERROR_BREAK(error, code) - -/*Set error var to the error code, and return it.*/ -#define CERROR_RETURN_ERROR(errorvar, code){\ - errorvar = code;\ - return code;\ -} - -/*Try the code, if it returns error, also return the error.*/ -#define CERROR_TRY_RETURN(call){\ - unsigned error = call;\ - if(error) return error;\ -} - -/*Set error var to the error code, and return from the void function.*/ -#define CERROR_RETURN(errorvar, code){\ - errorvar = code;\ - return;\ -} - -/* -About uivector, ucvector and string: --All of them wrap dynamic arrays or text strings in a similar way. --LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version. --The string tools are made to avoid problems with compilers that declare things like strncat as deprecated. --They're not used in the interface, only internally in this file as static functions. --As with many other structs in this file, the init and cleanup functions serve as ctor and dtor. -*/ - -#ifdef LODEPNG_COMPILE_ZLIB -#ifdef LODEPNG_COMPILE_ENCODER -/*dynamic vector of unsigned ints*/ -typedef struct uivector { - unsigned* data; - size_t size; /*size in number of unsigned longs*/ - size_t allocsize; /*allocated size in bytes*/ -} uivector; - -static void uivector_cleanup(void* p) { - ((uivector*)p)->size = ((uivector*)p)->allocsize = 0; - lodepng_free(((uivector*)p)->data); - ((uivector*)p)->data = NULL; -} - -/*returns 1 if success, 0 if failure ==> nothing done*/ -static unsigned uivector_resize(uivector* p, size_t size) { - size_t allocsize = size * sizeof(unsigned); - if(allocsize > p->allocsize) { - size_t newsize = allocsize + (p->allocsize >> 1u); - void* data = lodepng_realloc(p->data, newsize); - if(data) { - p->allocsize = newsize; - p->data = (unsigned*)data; - } - else return 0; /*error: not enough memory*/ - } - p->size = size; - return 1; /*success*/ -} - -static void uivector_init(uivector* p) { - p->data = NULL; - p->size = p->allocsize = 0; -} - -/*returns 1 if success, 0 if failure ==> nothing done*/ -static unsigned uivector_push_back(uivector* p, unsigned c) { - if(!uivector_resize(p, p->size + 1)) return 0; - p->data[p->size - 1] = c; - return 1; -} -#endif /*LODEPNG_COMPILE_ENCODER*/ -#endif /*LODEPNG_COMPILE_ZLIB*/ - -/* /////////////////////////////////////////////////////////////////////////// */ - -/*dynamic vector of unsigned chars*/ -typedef struct ucvector { - unsigned char* data; - size_t size; /*used size*/ - size_t allocsize; /*allocated size*/ -} ucvector; - -/*returns 1 if success, 0 if failure ==> nothing done*/ -static unsigned ucvector_reserve(ucvector* p, size_t size) { - if(size > p->allocsize) { - size_t newsize = size + (p->allocsize >> 1u); - void* data = lodepng_realloc(p->data, newsize); - if(data) { - p->allocsize = newsize; - p->data = (unsigned char*)data; - } - else return 0; /*error: not enough memory*/ - } - return 1; /*success*/ -} - -/*returns 1 if success, 0 if failure ==> nothing done*/ -static unsigned ucvector_resize(ucvector* p, size_t size) { - p->size = size; - return ucvector_reserve(p, size); -} - -static ucvector ucvector_init(unsigned char* buffer, size_t size) { - ucvector v; - v.data = buffer; - v.allocsize = v.size = size; - return v; -} - -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_PNG -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - -/*free string pointer and set it to NULL*/ -static void string_cleanup(char** out) { - lodepng_free(*out); - *out = NULL; -} - -/*also appends null termination character*/ -static char* alloc_string_sized(const char* in, size_t insize) { - char* out = (char*)lodepng_malloc(insize + 1); - if(out) { - lodepng_memcpy(out, in, insize); - out[insize] = 0; - } - return out; -} - -/* dynamically allocates a new string with a copy of the null terminated input text */ -static char* alloc_string(const char* in) { - return alloc_string_sized(in, lodepng_strlen(in)); -} -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -#endif /*LODEPNG_COMPILE_PNG*/ - -/* ////////////////////////////////////////////////////////////////////////// */ - -#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG) -static unsigned lodepng_read32bitInt(const unsigned char* buffer) { - return (((unsigned)buffer[0] << 24u) | ((unsigned)buffer[1] << 16u) | - ((unsigned)buffer[2] << 8u) | (unsigned)buffer[3]); -} -#endif /*defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_PNG)*/ - -#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER) -/*buffer must have at least 4 allocated bytes available*/ -static void lodepng_set32bitInt(unsigned char* buffer, unsigned value) { - buffer[0] = (unsigned char)((value >> 24) & 0xff); - buffer[1] = (unsigned char)((value >> 16) & 0xff); - buffer[2] = (unsigned char)((value >> 8) & 0xff); - buffer[3] = (unsigned char)((value ) & 0xff); -} -#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / File IO / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_DISK - -/* returns negative value on error. This should be pure C compatible, so no fstat. */ -static long lodepng_filesize(const char* filename) { - FILE* file; - long size; - file = fopen(filename, "rb"); - if(!file) return -1; - - if(fseek(file, 0, SEEK_END) != 0) { - fclose(file); - return -1; - } - - size = ftell(file); - /* It may give LONG_MAX as directory size, this is invalid for us. */ - if(size == LONG_MAX) size = -1; - - fclose(file); - return size; -} - -/* load file into buffer that already has the correct allocated size. Returns error code.*/ -static unsigned lodepng_buffer_file(unsigned char* out, size_t size, const char* filename) { - FILE* file; - size_t readsize; - file = fopen(filename, "rb"); - if(!file) return 78; - - readsize = fread(out, 1, size, file); - fclose(file); - - if(readsize != size) return 78; - return 0; -} - -unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename) { - long size = lodepng_filesize(filename); - if(size < 0) return 78; - *outsize = (size_t)size; - - *out = (unsigned char*)lodepng_malloc((size_t)size); - if(!(*out) && size > 0) return 83; /*the above malloc failed*/ - - return lodepng_buffer_file(*out, (size_t)size, filename); -} - -/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ -unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename) { - FILE* file; - file = fopen(filename, "wb" ); - if(!file) return 79; - fwrite(buffer, 1, buffersize, file); - fclose(file); - return 0; -} - -#endif /*LODEPNG_COMPILE_DISK*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* // End of common code and tools. Begin of Zlib related code. // */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_ZLIB -#ifdef LODEPNG_COMPILE_ENCODER - -typedef struct { - ucvector* data; - unsigned char bp; /*ok to overflow, indicates bit pos inside byte*/ -} LodePNGBitWriter; - -static void LodePNGBitWriter_init(LodePNGBitWriter* writer, ucvector* data) { - writer->data = data; - writer->bp = 0; -} - -/*TODO: this ignores potential out of memory errors*/ -#define WRITEBIT(writer, bit){\ - /* append new byte */\ - if(((writer->bp) & 7u) == 0) {\ - if(!ucvector_resize(writer->data, writer->data->size + 1)) return;\ - writer->data->data[writer->data->size - 1] = 0;\ - }\ - (writer->data->data[writer->data->size - 1]) |= (bit << ((writer->bp) & 7u));\ - ++writer->bp;\ -} - -/* LSB of value is written first, and LSB of bytes is used first */ -static void writeBits(LodePNGBitWriter* writer, unsigned value, size_t nbits) { - if(nbits == 1) { /* compiler should statically compile this case if nbits == 1 */ - WRITEBIT(writer, value); - } else { - /* TODO: increase output size only once here rather than in each WRITEBIT */ - size_t i; - for(i = 0; i != nbits; ++i) { - WRITEBIT(writer, (unsigned char)((value >> i) & 1)); - } - } -} - -/* This one is to use for adding huffman symbol, the value bits are written MSB first */ -static void writeBitsReversed(LodePNGBitWriter* writer, unsigned value, size_t nbits) { - size_t i; - for(i = 0; i != nbits; ++i) { - /* TODO: increase output size only once here rather than in each WRITEBIT */ - WRITEBIT(writer, (unsigned char)((value >> (nbits - 1u - i)) & 1u)); - } -} -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#ifdef LODEPNG_COMPILE_DECODER - -typedef struct { - const unsigned char* data; - size_t size; /*size of data in bytes*/ - size_t bitsize; /*size of data in bits, end of valid bp values, should be 8*size*/ - size_t bp; - unsigned buffer; /*buffer for reading bits. NOTE: 'unsigned' must support at least 32 bits*/ -} LodePNGBitReader; - -/* data size argument is in bytes. Returns error if size too large causing overflow */ -static unsigned LodePNGBitReader_init(LodePNGBitReader* reader, const unsigned char* data, size_t size) { - size_t temp; - reader->data = data; - reader->size = size; - /* size in bits, return error if overflow (if size_t is 32 bit this supports up to 500MB) */ - if(lodepng_mulofl(size, 8u, &reader->bitsize)) return 105; - /*ensure incremented bp can be compared to bitsize without overflow even when it would be incremented 32 too much and - trying to ensure 32 more bits*/ - if(lodepng_addofl(reader->bitsize, 64u, &temp)) return 105; - reader->bp = 0; - reader->buffer = 0; - return 0; /*ok*/ -} - -/* -ensureBits functions: -Ensures the reader can at least read nbits bits in one or more readBits calls, -safely even if not enough bits are available. -The nbits parameter is unused but is given for documentation purposes, error -checking for amount of bits must be done beforehand. -*/ - -/*See ensureBits documentation above. This one ensures up to 9 bits */ -static LODEPNG_INLINE void ensureBits9(LodePNGBitReader* reader, size_t nbits) { - size_t start = reader->bp >> 3u; - size_t size = reader->size; - if(start + 1u < size) { - reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u); - reader->buffer >>= (reader->bp & 7u); - } else { - reader->buffer = 0; - if(start + 0u < size) reader->buffer = reader->data[start + 0]; - reader->buffer >>= (reader->bp & 7u); - } - (void)nbits; -} - -/*See ensureBits documentation above. This one ensures up to 17 bits */ -static LODEPNG_INLINE void ensureBits17(LodePNGBitReader* reader, size_t nbits) { - size_t start = reader->bp >> 3u; - size_t size = reader->size; - if(start + 2u < size) { - reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | - ((unsigned)reader->data[start + 2] << 16u); - reader->buffer >>= (reader->bp & 7u); - } else { - reader->buffer = 0; - if(start + 0u < size) reader->buffer |= reader->data[start + 0]; - if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); - reader->buffer >>= (reader->bp & 7u); - } - (void)nbits; -} - -/*See ensureBits documentation above. This one ensures up to 25 bits */ -static LODEPNG_INLINE void ensureBits25(LodePNGBitReader* reader, size_t nbits) { - size_t start = reader->bp >> 3u; - size_t size = reader->size; - if(start + 3u < size) { - reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | - ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); - reader->buffer >>= (reader->bp & 7u); - } else { - reader->buffer = 0; - if(start + 0u < size) reader->buffer |= reader->data[start + 0]; - if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); - if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); - reader->buffer >>= (reader->bp & 7u); - } - (void)nbits; -} - -/*See ensureBits documentation above. This one ensures up to 32 bits */ -static LODEPNG_INLINE void ensureBits32(LodePNGBitReader* reader, size_t nbits) { - size_t start = reader->bp >> 3u; - size_t size = reader->size; - if(start + 4u < size) { - reader->buffer = (unsigned)reader->data[start + 0] | ((unsigned)reader->data[start + 1] << 8u) | - ((unsigned)reader->data[start + 2] << 16u) | ((unsigned)reader->data[start + 3] << 24u); - reader->buffer >>= (reader->bp & 7u); - reader->buffer |= (((unsigned)reader->data[start + 4] << 24u) << (8u - (reader->bp & 7u))); - } else { - reader->buffer = 0; - if(start + 0u < size) reader->buffer |= reader->data[start + 0]; - if(start + 1u < size) reader->buffer |= ((unsigned)reader->data[start + 1] << 8u); - if(start + 2u < size) reader->buffer |= ((unsigned)reader->data[start + 2] << 16u); - if(start + 3u < size) reader->buffer |= ((unsigned)reader->data[start + 3] << 24u); - reader->buffer >>= (reader->bp & 7u); - } - (void)nbits; -} - -/* Get bits without advancing the bit pointer. Must have enough bits available with ensureBits. Max nbits is 31. */ -static LODEPNG_INLINE unsigned peekBits(LodePNGBitReader* reader, size_t nbits) { - /* The shift allows nbits to be only up to 31. */ - return reader->buffer & ((1u << nbits) - 1u); -} - -/* Must have enough bits available with ensureBits */ -static LODEPNG_INLINE void advanceBits(LodePNGBitReader* reader, size_t nbits) { - reader->buffer >>= nbits; - reader->bp += nbits; -} - -/* Must have enough bits available with ensureBits */ -static LODEPNG_INLINE unsigned readBits(LodePNGBitReader* reader, size_t nbits) { - unsigned result = peekBits(reader, nbits); - advanceBits(reader, nbits); - return result; -} -#endif /*LODEPNG_COMPILE_DECODER*/ - -static unsigned reverseBits(unsigned bits, unsigned num) { - /*TODO: implement faster lookup table based version when needed*/ - unsigned i, result = 0; - for(i = 0; i < num; i++) result |= ((bits >> (num - i - 1u)) & 1u) << i; - return result; -} - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Deflate - Huffman / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#define FIRST_LENGTH_CODE_INDEX 257 -#define LAST_LENGTH_CODE_INDEX 285 -/*256 literals, the end code, some length codes, and 2 unused codes*/ -#define NUM_DEFLATE_CODE_SYMBOLS 288 -/*the distance codes have their own symbols, 30 used, 2 unused*/ -#define NUM_DISTANCE_SYMBOLS 32 -/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/ -#define NUM_CODE_LENGTH_CODES 19 - -/*the base lengths represented by codes 257-285*/ -static const unsigned LENGTHBASE[29] - = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, - 67, 83, 99, 115, 131, 163, 195, 227, 258}; - -/*the extra bits used by codes 257-285 (added to base length)*/ -static const unsigned LENGTHEXTRA[29] - = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, - 4, 4, 4, 4, 5, 5, 5, 5, 0}; - -/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/ -static const unsigned DISTANCEBASE[30] - = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, - 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577}; - -/*the extra bits of backwards distances (added to base)*/ -static const unsigned DISTANCEEXTRA[30] - = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, - 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13}; - -/*the order in which "code length alphabet code lengths" are stored as specified by deflate, out of this the huffman -tree of the dynamic huffman tree lengths is generated*/ -static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES] - = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; - -/* ////////////////////////////////////////////////////////////////////////// */ - -/* -Huffman tree struct, containing multiple representations of the tree -*/ -typedef struct HuffmanTree { - unsigned* codes; /*the huffman codes (bit patterns representing the symbols)*/ - unsigned* lengths; /*the lengths of the huffman codes*/ - unsigned maxbitlen; /*maximum number of bits a single code can get*/ - unsigned numcodes; /*number of symbols in the alphabet = number of codes*/ - /* for reading only */ - unsigned char* table_len; /*length of symbol from lookup table, or max length if secondary lookup needed*/ - unsigned short* table_value; /*value of symbol from lookup table, or pointer to secondary table if needed*/ -} HuffmanTree; - -static void HuffmanTree_init(HuffmanTree* tree) { - tree->codes = 0; - tree->lengths = 0; - tree->table_len = 0; - tree->table_value = 0; -} - -static void HuffmanTree_cleanup(HuffmanTree* tree) { - lodepng_free(tree->codes); - lodepng_free(tree->lengths); - lodepng_free(tree->table_len); - lodepng_free(tree->table_value); -} - -/* amount of bits for first huffman table lookup (aka root bits), see HuffmanTree_makeTable and huffmanDecodeSymbol.*/ -/* values 8u and 9u work the fastest */ -#define FIRSTBITS 9u - -/* a symbol value too big to represent any valid symbol, to indicate reading disallowed huffman bits combination, -which is possible in case of only 0 or 1 present symbols. */ -#define INVALIDSYMBOL 65535u - -/* make table for huffman decoding */ -static unsigned HuffmanTree_makeTable(HuffmanTree* tree) { - static const unsigned headsize = 1u << FIRSTBITS; /*size of the first table*/ - static const unsigned mask = (1u << FIRSTBITS) /*headsize*/ - 1u; - size_t i, numpresent, pointer, size; /*total table size*/ - unsigned* maxlens = (unsigned*)lodepng_malloc(headsize * sizeof(unsigned)); - if(!maxlens) return 83; /*alloc fail*/ - - /* compute maxlens: max total bit length of symbols sharing prefix in the first table*/ - lodepng_memset(maxlens, 0, headsize * sizeof(*maxlens)); - for(i = 0; i < tree->numcodes; i++) { - unsigned symbol = tree->codes[i]; - unsigned l = tree->lengths[i]; - unsigned index; - if(l <= FIRSTBITS) continue; /*symbols that fit in first table don't increase secondary table size*/ - /*get the FIRSTBITS MSBs, the MSBs of the symbol are encoded first. See later comment about the reversing*/ - index = reverseBits(symbol >> (l - FIRSTBITS), FIRSTBITS); - maxlens[index] = LODEPNG_MAX(maxlens[index], l); - } - /* compute total table size: size of first table plus all secondary tables for symbols longer than FIRSTBITS */ - size = headsize; - for(i = 0; i < headsize; ++i) { - unsigned l = maxlens[i]; - if(l > FIRSTBITS) size += (1u << (l - FIRSTBITS)); - } - tree->table_len = (unsigned char*)lodepng_malloc(size * sizeof(*tree->table_len)); - tree->table_value = (unsigned short*)lodepng_malloc(size * sizeof(*tree->table_value)); - if(!tree->table_len || !tree->table_value) { - lodepng_free(maxlens); - /* freeing tree->table values is done at a higher scope */ - return 83; /*alloc fail*/ - } - /*initialize with an invalid length to indicate unused entries*/ - for(i = 0; i < size; ++i) tree->table_len[i] = 16; - - /*fill in the first table for long symbols: max prefix size and pointer to secondary tables*/ - pointer = headsize; - for(i = 0; i < headsize; ++i) { - unsigned l = maxlens[i]; - if(l <= FIRSTBITS) continue; - tree->table_len[i] = l; - tree->table_value[i] = pointer; - pointer += (1u << (l - FIRSTBITS)); - } - lodepng_free(maxlens); - - /*fill in the first table for short symbols, or secondary table for long symbols*/ - numpresent = 0; - for(i = 0; i < tree->numcodes; ++i) { - unsigned l = tree->lengths[i]; - unsigned symbol = tree->codes[i]; /*the huffman bit pattern. i itself is the value.*/ - /*reverse bits, because the huffman bits are given in MSB first order but the bit reader reads LSB first*/ - unsigned reverse = reverseBits(symbol, l); - if(l == 0) continue; - numpresent++; - - if(l <= FIRSTBITS) { - /*short symbol, fully in first table, replicated num times if l < FIRSTBITS*/ - unsigned num = 1u << (FIRSTBITS - l); - unsigned j; - for(j = 0; j < num; ++j) { - /*bit reader will read the l bits of symbol first, the remaining FIRSTBITS - l bits go to the MSB's*/ - unsigned index = reverse | (j << l); - if(tree->table_len[index] != 16) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ - tree->table_len[index] = l; - tree->table_value[index] = i; - } - } else { - /*long symbol, shares prefix with other long symbols in first lookup table, needs second lookup*/ - /*the FIRSTBITS MSBs of the symbol are the first table index*/ - unsigned index = reverse & mask; - unsigned maxlen = tree->table_len[index]; - /*log2 of secondary table length, should be >= l - FIRSTBITS*/ - unsigned tablelen = maxlen - FIRSTBITS; - unsigned start = tree->table_value[index]; /*starting index in secondary table*/ - unsigned num = 1u << (tablelen - (l - FIRSTBITS)); /*amount of entries of this symbol in secondary table*/ - unsigned j; - if(maxlen < l) return 55; /*invalid tree: long symbol shares prefix with short symbol*/ - for(j = 0; j < num; ++j) { - unsigned reverse2 = reverse >> FIRSTBITS; /* l - FIRSTBITS bits */ - unsigned index2 = start + (reverse2 | (j << (l - FIRSTBITS))); - tree->table_len[index2] = l; - tree->table_value[index2] = i; - } - } - } - - if(numpresent < 2) { - /* In case of exactly 1 symbol, in theory the huffman symbol needs 0 bits, - but deflate uses 1 bit instead. In case of 0 symbols, no symbols can - appear at all, but such huffman tree could still exist (e.g. if distance - codes are never used). In both cases, not all symbols of the table will be - filled in. Fill them in with an invalid symbol value so returning them from - huffmanDecodeSymbol will cause error. */ - for(i = 0; i < size; ++i) { - if(tree->table_len[i] == 16) { - /* As length, use a value smaller than FIRSTBITS for the head table, - and a value larger than FIRSTBITS for the secondary table, to ensure - valid behavior for advanceBits when reading this symbol. */ - tree->table_len[i] = (i < headsize) ? 1 : (FIRSTBITS + 1); - tree->table_value[i] = INVALIDSYMBOL; - } - } - } else { - /* A good huffman tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. - If that is not the case (due to too long length codes), the table will not - have been fully used, and this is an error (not all bit combinations can be - decoded): an oversubscribed huffman tree, indicated by error 55. */ - for(i = 0; i < size; ++i) { - if(tree->table_len[i] == 16) return 55; - } - } - - return 0; -} - -/* -Second step for the ...makeFromLengths and ...makeFromFrequencies functions. -numcodes, lengths and maxbitlen must already be filled in correctly. return -value is error. -*/ -static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) { - unsigned* blcount; - unsigned* nextcode; - unsigned error = 0; - unsigned bits, n; - - tree->codes = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned)); - blcount = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned)); - nextcode = (unsigned*)lodepng_malloc((tree->maxbitlen + 1) * sizeof(unsigned)); - if(!tree->codes || !blcount || !nextcode) error = 83; /*alloc fail*/ - - if(!error) { - for(n = 0; n != tree->maxbitlen + 1; n++) blcount[n] = nextcode[n] = 0; - /*step 1: count number of instances of each code length*/ - for(bits = 0; bits != tree->numcodes; ++bits) ++blcount[tree->lengths[bits]]; - /*step 2: generate the nextcode values*/ - for(bits = 1; bits <= tree->maxbitlen; ++bits) { - nextcode[bits] = (nextcode[bits - 1] + blcount[bits - 1]) << 1u; - } - /*step 3: generate all the codes*/ - for(n = 0; n != tree->numcodes; ++n) { - if(tree->lengths[n] != 0) { - tree->codes[n] = nextcode[tree->lengths[n]]++; - /*remove superfluous bits from the code*/ - tree->codes[n] &= ((1u << tree->lengths[n]) - 1u); - } - } - } - - lodepng_free(blcount); - lodepng_free(nextcode); - - if(!error) error = HuffmanTree_makeTable(tree); - return error; -} - -/* -given the code lengths (as stored in the PNG file), generate the tree as defined -by Deflate. maxbitlen is the maximum bits that a code in the tree can have. -return value is error. -*/ -static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen, - size_t numcodes, unsigned maxbitlen) { - unsigned i; - tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned)); - if(!tree->lengths) return 83; /*alloc fail*/ - for(i = 0; i != numcodes; ++i) tree->lengths[i] = bitlen[i]; - tree->numcodes = (unsigned)numcodes; /*number of symbols*/ - tree->maxbitlen = maxbitlen; - return HuffmanTree_makeFromLengths2(tree); -} - -#ifdef LODEPNG_COMPILE_ENCODER - -/*BPM: Boundary Package Merge, see "A Fast and Space-Economical Algorithm for Length-Limited Coding", -Jyrki Katajainen, Alistair Moffat, Andrew Turpin, 1995.*/ - -/*chain node for boundary package merge*/ -typedef struct BPMNode { - int weight; /*the sum of all weights in this chain*/ - unsigned index; /*index of this leaf node (called "count" in the paper)*/ - struct BPMNode* tail; /*the next nodes in this chain (null if last)*/ - int in_use; -} BPMNode; - -/*lists of chains*/ -typedef struct BPMLists { - /*memory pool*/ - unsigned memsize; - BPMNode* memory; - unsigned numfree; - unsigned nextfree; - BPMNode** freelist; - /*two heads of lookahead chains per list*/ - unsigned listsize; - BPMNode** chains0; - BPMNode** chains1; -} BPMLists; - -/*creates a new chain node with the given parameters, from the memory in the lists */ -static BPMNode* bpmnode_create(BPMLists* lists, int weight, unsigned index, BPMNode* tail) { - unsigned i; - BPMNode* result; - - /*memory full, so garbage collect*/ - if(lists->nextfree >= lists->numfree) { - /*mark only those that are in use*/ - for(i = 0; i != lists->memsize; ++i) lists->memory[i].in_use = 0; - for(i = 0; i != lists->listsize; ++i) { - BPMNode* node; - for(node = lists->chains0[i]; node != 0; node = node->tail) node->in_use = 1; - for(node = lists->chains1[i]; node != 0; node = node->tail) node->in_use = 1; - } - /*collect those that are free*/ - lists->numfree = 0; - for(i = 0; i != lists->memsize; ++i) { - if(!lists->memory[i].in_use) lists->freelist[lists->numfree++] = &lists->memory[i]; - } - lists->nextfree = 0; - } - - result = lists->freelist[lists->nextfree++]; - result->weight = weight; - result->index = index; - result->tail = tail; - return result; -} - -/*sort the leaves with stable mergesort*/ -static void bpmnode_sort(BPMNode* leaves, size_t num) { - BPMNode* mem = (BPMNode*)lodepng_malloc(sizeof(*leaves) * num); - size_t width, counter = 0; - for(width = 1; width < num; width *= 2) { - BPMNode* a = (counter & 1) ? mem : leaves; - BPMNode* b = (counter & 1) ? leaves : mem; - size_t p; - for(p = 0; p < num; p += 2 * width) { - size_t q = (p + width > num) ? num : (p + width); - size_t r = (p + 2 * width > num) ? num : (p + 2 * width); - size_t i = p, j = q, k; - for(k = p; k < r; k++) { - if(i < q && (j >= r || a[i].weight <= a[j].weight)) b[k] = a[i++]; - else b[k] = a[j++]; - } - } - counter++; - } - if(counter & 1) lodepng_memcpy(leaves, mem, sizeof(*leaves) * num); - lodepng_free(mem); -} - -/*Boundary Package Merge step, numpresent is the amount of leaves, and c is the current chain.*/ -static void boundaryPM(BPMLists* lists, BPMNode* leaves, size_t numpresent, int c, int num) { - unsigned lastindex = lists->chains1[c]->index; - - if(c == 0) { - if(lastindex >= numpresent) return; - lists->chains0[c] = lists->chains1[c]; - lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, 0); - } else { - /*sum of the weights of the head nodes of the previous lookahead chains.*/ - int sum = lists->chains0[c - 1]->weight + lists->chains1[c - 1]->weight; - lists->chains0[c] = lists->chains1[c]; - if(lastindex < numpresent && sum > leaves[lastindex].weight) { - lists->chains1[c] = bpmnode_create(lists, leaves[lastindex].weight, lastindex + 1, lists->chains1[c]->tail); - return; - } - lists->chains1[c] = bpmnode_create(lists, sum, lastindex, lists->chains1[c - 1]); - /*in the end we are only interested in the chain of the last list, so no - need to recurse if we're at the last one (this gives measurable speedup)*/ - if(num + 1 < (int)(2 * numpresent - 2)) { - boundaryPM(lists, leaves, numpresent, c - 1, num); - boundaryPM(lists, leaves, numpresent, c - 1, num); - } - } -} - -unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, - size_t numcodes, unsigned maxbitlen) { - unsigned error = 0; - unsigned i; - size_t numpresent = 0; /*number of symbols with non-zero frequency*/ - BPMNode* leaves; /*the symbols, only those with > 0 frequency*/ - - if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/ - if((1u << maxbitlen) < (unsigned)numcodes) return 80; /*error: represent all symbols*/ - - leaves = (BPMNode*)lodepng_malloc(numcodes * sizeof(*leaves)); - if(!leaves) return 83; /*alloc fail*/ - - for(i = 0; i != numcodes; ++i) { - if(frequencies[i] > 0) { - leaves[numpresent].weight = (int)frequencies[i]; - leaves[numpresent].index = i; - ++numpresent; - } - } - - lodepng_memset(lengths, 0, numcodes * sizeof(*lengths)); - - /*ensure at least two present symbols. There should be at least one symbol - according to RFC 1951 section 3.2.7. Some decoders incorrectly require two. To - make these work as well ensure there are at least two symbols. The - Package-Merge code below also doesn't work correctly if there's only one - symbol, it'd give it the theoretical 0 bits but in practice zlib wants 1 bit*/ - if(numpresent == 0) { - lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/ - } else if(numpresent == 1) { - lengths[leaves[0].index] = 1; - lengths[leaves[0].index == 0 ? 1 : 0] = 1; - } else { - BPMLists lists; - BPMNode* node; - - bpmnode_sort(leaves, numpresent); - - lists.listsize = maxbitlen; - lists.memsize = 2 * maxbitlen * (maxbitlen + 1); - lists.nextfree = 0; - lists.numfree = lists.memsize; - lists.memory = (BPMNode*)lodepng_malloc(lists.memsize * sizeof(*lists.memory)); - lists.freelist = (BPMNode**)lodepng_malloc(lists.memsize * sizeof(BPMNode*)); - lists.chains0 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); - lists.chains1 = (BPMNode**)lodepng_malloc(lists.listsize * sizeof(BPMNode*)); - if(!lists.memory || !lists.freelist || !lists.chains0 || !lists.chains1) error = 83; /*alloc fail*/ - - if(!error) { - for(i = 0; i != lists.memsize; ++i) lists.freelist[i] = &lists.memory[i]; - - bpmnode_create(&lists, leaves[0].weight, 1, 0); - bpmnode_create(&lists, leaves[1].weight, 2, 0); - - for(i = 0; i != lists.listsize; ++i) { - lists.chains0[i] = &lists.memory[0]; - lists.chains1[i] = &lists.memory[1]; - } - - /*each boundaryPM call adds one chain to the last list, and we need 2 * numpresent - 2 chains.*/ - for(i = 2; i != 2 * numpresent - 2; ++i) boundaryPM(&lists, leaves, numpresent, (int)maxbitlen - 1, (int)i); - - for(node = lists.chains1[maxbitlen - 1]; node; node = node->tail) { - for(i = 0; i != node->index; ++i) ++lengths[leaves[i].index]; - } - } - - lodepng_free(lists.memory); - lodepng_free(lists.freelist); - lodepng_free(lists.chains0); - lodepng_free(lists.chains1); - } - - lodepng_free(leaves); - return error; -} - -/*Create the Huffman tree given the symbol frequencies*/ -static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, - size_t mincodes, size_t numcodes, unsigned maxbitlen) { - unsigned error = 0; - while(!frequencies[numcodes - 1] && numcodes > mincodes) --numcodes; /*trim zeroes*/ - tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned)); - if(!tree->lengths) return 83; /*alloc fail*/ - tree->maxbitlen = maxbitlen; - tree->numcodes = (unsigned)numcodes; /*number of symbols*/ - - error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen); - if(!error) error = HuffmanTree_makeFromLengths2(tree); - return error; -} -#endif /*LODEPNG_COMPILE_ENCODER*/ - -/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/ -static unsigned generateFixedLitLenTree(HuffmanTree* tree) { - unsigned i, error = 0; - unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); - if(!bitlen) return 83; /*alloc fail*/ - - /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/ - for(i = 0; i <= 143; ++i) bitlen[i] = 8; - for(i = 144; i <= 255; ++i) bitlen[i] = 9; - for(i = 256; i <= 279; ++i) bitlen[i] = 7; - for(i = 280; i <= 287; ++i) bitlen[i] = 8; - - error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15); - - lodepng_free(bitlen); - return error; -} - -/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/ -static unsigned generateFixedDistanceTree(HuffmanTree* tree) { - unsigned i, error = 0; - unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); - if(!bitlen) return 83; /*alloc fail*/ - - /*there are 32 distance codes, but 30-31 are unused*/ - for(i = 0; i != NUM_DISTANCE_SYMBOLS; ++i) bitlen[i] = 5; - error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15); - - lodepng_free(bitlen); - return error; -} - -#ifdef LODEPNG_COMPILE_DECODER - -/* -returns the code. The bit reader must already have been ensured at least 15 bits -*/ -static unsigned huffmanDecodeSymbol(LodePNGBitReader* reader, const HuffmanTree* codetree) { - unsigned short code = peekBits(reader, FIRSTBITS); - unsigned short l = codetree->table_len[code]; - unsigned short value = codetree->table_value[code]; - if(l <= FIRSTBITS) { - advanceBits(reader, l); - return value; - } else { - advanceBits(reader, FIRSTBITS); - value += peekBits(reader, l - FIRSTBITS); - advanceBits(reader, codetree->table_len[value] - FIRSTBITS); - return codetree->table_value[value]; - } -} -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_DECODER - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Inflator (Decompressor) / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -/*get the tree of a deflated block with fixed tree, as specified in the deflate specification -Returns error code.*/ -static unsigned getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d) { - unsigned error = generateFixedLitLenTree(tree_ll); - if(error) return error; - return generateFixedDistanceTree(tree_d); -} - -/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/ -static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d, - LodePNGBitReader* reader) { - /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/ - unsigned error = 0; - unsigned n, HLIT, HDIST, HCLEN, i; - - /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/ - unsigned* bitlen_ll = 0; /*lit,len code lengths*/ - unsigned* bitlen_d = 0; /*dist code lengths*/ - /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/ - unsigned* bitlen_cl = 0; - HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/ - - if(reader->bitsize - reader->bp < 14) return 49; /*error: the bit pointer is or will go past the memory*/ - ensureBits17(reader, 14); - - /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/ - HLIT = readBits(reader, 5) + 257; - /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/ - HDIST = readBits(reader, 5) + 1; - /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/ - HCLEN = readBits(reader, 4) + 4; - - bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned)); - if(!bitlen_cl) return 83 /*alloc fail*/; - - HuffmanTree_init(&tree_cl); - - while(!error) { - /*read the code length codes out of 3 * (amount of code length codes) bits*/ - if(lodepng_gtofl(reader->bp, HCLEN * 3, reader->bitsize)) { - ERROR_BREAK(50); /*error: the bit pointer is or will go past the memory*/ - } - for(i = 0; i != HCLEN; ++i) { - ensureBits9(reader, 3); /*out of bounds already checked above */ - bitlen_cl[CLCL_ORDER[i]] = readBits(reader, 3); - } - for(i = HCLEN; i != NUM_CODE_LENGTH_CODES; ++i) { - bitlen_cl[CLCL_ORDER[i]] = 0; - } - - error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7); - if(error) break; - - /*now we can use this tree to read the lengths for the tree that this function will return*/ - bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned)); - bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned)); - if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/); - lodepng_memset(bitlen_ll, 0, NUM_DEFLATE_CODE_SYMBOLS * sizeof(*bitlen_ll)); - lodepng_memset(bitlen_d, 0, NUM_DISTANCE_SYMBOLS * sizeof(*bitlen_d)); - - /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/ - i = 0; - while(i < HLIT + HDIST) { - unsigned code; - ensureBits25(reader, 22); /* up to 15 bits for huffman code, up to 7 extra bits below*/ - code = huffmanDecodeSymbol(reader, &tree_cl); - if(code <= 15) /*a length code*/ { - if(i < HLIT) bitlen_ll[i] = code; - else bitlen_d[i - HLIT] = code; - ++i; - } else if(code == 16) /*repeat previous*/ { - unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/ - unsigned value; /*set value to the previous code*/ - - if(i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/ - - replength += readBits(reader, 2); - - if(i < HLIT + 1) value = bitlen_ll[i - 1]; - else value = bitlen_d[i - HLIT - 1]; - /*repeat this value in the next lengths*/ - for(n = 0; n < replength; ++n) { - if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/ - if(i < HLIT) bitlen_ll[i] = value; - else bitlen_d[i - HLIT] = value; - ++i; - } - } else if(code == 17) /*repeat "0" 3-10 times*/ { - unsigned replength = 3; /*read in the bits that indicate repeat length*/ - replength += readBits(reader, 3); - - /*repeat this value in the next lengths*/ - for(n = 0; n < replength; ++n) { - if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/ - - if(i < HLIT) bitlen_ll[i] = 0; - else bitlen_d[i - HLIT] = 0; - ++i; - } - } else if(code == 18) /*repeat "0" 11-138 times*/ { - unsigned replength = 11; /*read in the bits that indicate repeat length*/ - replength += readBits(reader, 7); - - /*repeat this value in the next lengths*/ - for(n = 0; n < replength; ++n) { - if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/ - - if(i < HLIT) bitlen_ll[i] = 0; - else bitlen_d[i - HLIT] = 0; - ++i; - } - } else /*if(code == INVALIDSYMBOL)*/ { - ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ - } - /*check if any of the ensureBits above went out of bounds*/ - if(reader->bp > reader->bitsize) { - /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol - (10=no endcode, 11=wrong jump outside of tree)*/ - /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ - ERROR_BREAK(50); /*error, bit pointer jumps past memory*/ - } - } - if(error) break; - - if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/ - - /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/ - error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15); - if(error) break; - error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15); - - break; /*end of error-while*/ - } - - lodepng_free(bitlen_cl); - lodepng_free(bitlen_ll); - lodepng_free(bitlen_d); - HuffmanTree_cleanup(&tree_cl); - - return error; -} - -/*inflate a block with dynamic of fixed Huffman tree. btype must be 1 or 2.*/ -static unsigned inflateHuffmanBlock(ucvector* out, LodePNGBitReader* reader, - unsigned btype, size_t max_output_size) { - unsigned error = 0; - HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/ - HuffmanTree tree_d; /*the huffman tree for distance codes*/ - const size_t reserved_size = 260; /* must be at least 258 for max length, and a few extra for adding a few extra literals */ - int done = 0; - - if(!ucvector_reserve(out, out->size + reserved_size)) return 83; /*alloc fail*/ - - HuffmanTree_init(&tree_ll); - HuffmanTree_init(&tree_d); - - if(btype == 1) error = getTreeInflateFixed(&tree_ll, &tree_d); - else /*if(btype == 2)*/ error = getTreeInflateDynamic(&tree_ll, &tree_d, reader); - - - while(!error && !done) /*decode all symbols until end reached, breaks at end code*/ { - /*code_ll is literal, length or end code*/ - unsigned code_ll; - /* ensure enough bits for 2 huffman code reads (15 bits each): if the first is a literal, a second literal is read at once. This - appears to be slightly faster, than ensuring 20 bits here for 1 huffman symbol and the potential 5 extra bits for the length symbol.*/ - ensureBits32(reader, 30); - code_ll = huffmanDecodeSymbol(reader, &tree_ll); - if(code_ll <= 255) { - /*slightly faster code path if multiple literals in a row*/ - out->data[out->size++] = (unsigned char)code_ll; - code_ll = huffmanDecodeSymbol(reader, &tree_ll); - } - if(code_ll <= 255) /*literal symbol*/ { - out->data[out->size++] = (unsigned char)code_ll; - } else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/ { - unsigned code_d, distance; - unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/ - size_t start, backward, length; - - /*part 1: get length base*/ - length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX]; - - /*part 2: get extra bits and add the value of that to length*/ - numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX]; - if(numextrabits_l != 0) { - /* bits already ensured above */ - ensureBits25(reader, 5); - length += readBits(reader, numextrabits_l); - } - - /*part 3: get distance code*/ - ensureBits32(reader, 28); /* up to 15 for the huffman symbol, up to 13 for the extra bits */ - code_d = huffmanDecodeSymbol(reader, &tree_d); - if(code_d > 29) { - if(code_d <= 31) { - ERROR_BREAK(18); /*error: invalid distance code (30-31 are never used)*/ - } else /* if(code_d == INVALIDSYMBOL) */{ - ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ - } - } - distance = DISTANCEBASE[code_d]; - - /*part 4: get extra bits from distance*/ - numextrabits_d = DISTANCEEXTRA[code_d]; - if(numextrabits_d != 0) { - /* bits already ensured above */ - distance += readBits(reader, numextrabits_d); - } - - /*part 5: fill in all the out[n] values based on the length and dist*/ - start = out->size; - if(distance > start) ERROR_BREAK(52); /*too long backward distance*/ - backward = start - distance; - - out->size += length; - if(distance < length) { - size_t forward; - lodepng_memcpy(out->data + start, out->data + backward, distance); - start += distance; - for(forward = distance; forward < length; ++forward) { - out->data[start++] = out->data[backward++]; - } - } else { - lodepng_memcpy(out->data + start, out->data + backward, length); - } - } else if(code_ll == 256) { - done = 1; /*end code, finish the loop*/ - } else /*if(code_ll == INVALIDSYMBOL)*/ { - ERROR_BREAK(16); /*error: tried to read disallowed huffman symbol*/ - } - if(out->allocsize - out->size < reserved_size) { - if(!ucvector_reserve(out, out->size + reserved_size)) ERROR_BREAK(83); /*alloc fail*/ - } - /*check if any of the ensureBits above went out of bounds*/ - if(reader->bp > reader->bitsize) { - /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol - (10=no endcode, 11=wrong jump outside of tree)*/ - /* TODO: revise error codes 10,11,50: the above comment is no longer valid */ - ERROR_BREAK(51); /*error, bit pointer jumps past memory*/ - } - if(max_output_size && out->size > max_output_size) { - ERROR_BREAK(109); /*error, larger than max size*/ - } - } - - HuffmanTree_cleanup(&tree_ll); - HuffmanTree_cleanup(&tree_d); - - return error; -} - -static unsigned inflateNoCompression(ucvector* out, LodePNGBitReader* reader, - const LodePNGDecompressSettings* settings) { - size_t bytepos; - size_t size = reader->size; - unsigned LEN, NLEN, error = 0; - - /*go to first boundary of byte*/ - bytepos = (reader->bp + 7u) >> 3u; - - /*read LEN (2 bytes) and NLEN (2 bytes)*/ - if(bytepos + 4 >= size) return 52; /*error, bit pointer will jump past memory*/ - LEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; - NLEN = (unsigned)reader->data[bytepos] + ((unsigned)reader->data[bytepos + 1] << 8u); bytepos += 2; - - /*check if 16-bit NLEN is really the one's complement of LEN*/ - if(!settings->ignore_nlen && LEN + NLEN != 65535) { - return 21; /*error: NLEN is not one's complement of LEN*/ - } - - if(!ucvector_resize(out, out->size + LEN)) return 83; /*alloc fail*/ - - /*read the literal data: LEN bytes are now stored in the out buffer*/ - if(bytepos + LEN > size) return 23; /*error: reading outside of in buffer*/ - - lodepng_memcpy(out->data + out->size - LEN, reader->data + bytepos, LEN); - bytepos += LEN; - - reader->bp = bytepos << 3u; - - return error; -} - -static unsigned lodepng_inflatev(ucvector* out, - const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings) { - unsigned BFINAL = 0; - LodePNGBitReader reader; - unsigned error = LodePNGBitReader_init(&reader, in, insize); - - if(error) return error; - - while(!BFINAL) { - unsigned BTYPE; - if(reader.bitsize - reader.bp < 3) return 52; /*error, bit pointer will jump past memory*/ - ensureBits9(&reader, 3); - BFINAL = readBits(&reader, 1); - BTYPE = readBits(&reader, 2); - - if(BTYPE == 3) return 20; /*error: invalid BTYPE*/ - else if(BTYPE == 0) error = inflateNoCompression(out, &reader, settings); /*no compression*/ - else error = inflateHuffmanBlock(out, &reader, BTYPE, settings->max_output_size); /*compression, BTYPE 01 or 10*/ - if(!error && settings->max_output_size && out->size > settings->max_output_size) error = 109; - if(error) break; - } - - return error; -} - -unsigned lodepng_inflate(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings) { - ucvector v = ucvector_init(*out, *outsize); - unsigned error = lodepng_inflatev(&v, in, insize, settings); - *out = v.data; - *outsize = v.size; - return error; -} - -static unsigned inflatev(ucvector* out, const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings) { - if(settings->custom_inflate) { - unsigned error = settings->custom_inflate(&out->data, &out->size, in, insize, settings); - out->allocsize = out->size; - if(error) { - /*the custom inflate is allowed to have its own error codes, however, we translate it to code 110*/ - error = 110; - /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/ - if(settings->max_output_size && out->size > settings->max_output_size) error = 109; - } - return error; - } else { - return lodepng_inflatev(out, in, insize, settings); - } -} - -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Deflator (Compressor) / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258; - -/*search the index in the array, that has the largest value smaller than or equal to the given value, -given array must be sorted (if no value is smaller, it returns the size of the given array)*/ -static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value) { - /*binary search (only small gain over linear). TODO: use CPU log2 instruction for getting symbols instead*/ - size_t left = 1; - size_t right = array_size - 1; - - while(left <= right) { - size_t mid = (left + right) >> 1; - if(array[mid] >= value) right = mid - 1; - else left = mid + 1; - } - if(left >= array_size || array[left] > value) left--; - return left; -} - -static void addLengthDistance(uivector* values, size_t length, size_t distance) { - /*values in encoded vector are those used by deflate: - 0-255: literal bytes - 256: end - 257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits) - 286-287: invalid*/ - - unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length); - unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]); - unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance); - unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]); - - size_t pos = values->size; - /*TODO: return error when this fails (out of memory)*/ - unsigned ok = uivector_resize(values, values->size + 4); - if(ok) { - values->data[pos + 0] = length_code + FIRST_LENGTH_CODE_INDEX; - values->data[pos + 1] = extra_length; - values->data[pos + 2] = dist_code; - values->data[pos + 3] = extra_distance; - } -} - -/*3 bytes of data get encoded into two bytes. The hash cannot use more than 3 -bytes as input because 3 is the minimum match length for deflate*/ -static const unsigned HASH_NUM_VALUES = 65536; -static const unsigned HASH_BIT_MASK = 65535; /*HASH_NUM_VALUES - 1, but C90 does not like that as initializer*/ - -typedef struct Hash { - int* head; /*hash value to head circular pos - can be outdated if went around window*/ - /*circular pos to prev circular pos*/ - unsigned short* chain; - int* val; /*circular pos to hash value*/ - - /*TODO: do this not only for zeros but for any repeated byte. However for PNG - it's always going to be the zeros that dominate, so not important for PNG*/ - int* headz; /*similar to head, but for chainz*/ - unsigned short* chainz; /*those with same amount of zeros*/ - unsigned short* zeros; /*length of zeros streak, used as a second hash chain*/ -} Hash; - -static unsigned hash_init(Hash* hash, unsigned windowsize) { - unsigned i; - hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES); - hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize); - hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); - - hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); - hash->headz = (int*)lodepng_malloc(sizeof(int) * (MAX_SUPPORTED_DEFLATE_LENGTH + 1)); - hash->chainz = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize); - - if(!hash->head || !hash->chain || !hash->val || !hash->headz|| !hash->chainz || !hash->zeros) { - return 83; /*alloc fail*/ - } - - /*initialize hash table*/ - for(i = 0; i != HASH_NUM_VALUES; ++i) hash->head[i] = -1; - for(i = 0; i != windowsize; ++i) hash->val[i] = -1; - for(i = 0; i != windowsize; ++i) hash->chain[i] = i; /*same value as index indicates uninitialized*/ - - for(i = 0; i <= MAX_SUPPORTED_DEFLATE_LENGTH; ++i) hash->headz[i] = -1; - for(i = 0; i != windowsize; ++i) hash->chainz[i] = i; /*same value as index indicates uninitialized*/ - - return 0; -} - -static void hash_cleanup(Hash* hash) { - lodepng_free(hash->head); - lodepng_free(hash->val); - lodepng_free(hash->chain); - - lodepng_free(hash->zeros); - lodepng_free(hash->headz); - lodepng_free(hash->chainz); -} - - - -static unsigned getHash(const unsigned char* data, size_t size, size_t pos) { - unsigned result = 0; - if(pos + 2 < size) { - /*A simple shift and xor hash is used. Since the data of PNGs is dominated - by zeroes due to the filters, a better hash does not have a significant - effect on speed in traversing the chain, and causes more time spend on - calculating the hash.*/ - result ^= ((unsigned)data[pos + 0] << 0u); - result ^= ((unsigned)data[pos + 1] << 4u); - result ^= ((unsigned)data[pos + 2] << 8u); - } else { - size_t amount, i; - if(pos >= size) return 0; - amount = size - pos; - for(i = 0; i != amount; ++i) result ^= ((unsigned)data[pos + i] << (i * 8u)); - } - return result & HASH_BIT_MASK; -} - -static unsigned countZeros(const unsigned char* data, size_t size, size_t pos) { - const unsigned char* start = data + pos; - const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH; - if(end > data + size) end = data + size; - data = start; - while(data != end && *data == 0) ++data; - /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/ - return (unsigned)(data - start); -} - -/*wpos = pos & (windowsize - 1)*/ -static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned short numzeros) { - hash->val[wpos] = (int)hashval; - if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval]; - hash->head[hashval] = (int)wpos; - - hash->zeros[wpos] = numzeros; - if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros]; - hash->headz[numzeros] = (int)wpos; -} - -/* -LZ77-encode the data. Return value is error code. The input are raw bytes, the output -is in the form of unsigned integers with codes representing for example literal bytes, or -length/distance pairs. -It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a -sliding window (of windowsize) is used, and all past bytes in that window can be used as -the "dictionary". A brute force search through all possible distances would be slow, and -this hash technique is one out of several ways to speed this up. -*/ -static unsigned encodeLZ77(uivector* out, Hash* hash, - const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize, - unsigned minmatch, unsigned nicematch, unsigned lazymatching) { - size_t pos; - unsigned i, error = 0; - /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/ - unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8u; - unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64; - - unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/ - unsigned numzeros = 0; - - unsigned offset; /*the offset represents the distance in LZ77 terminology*/ - unsigned length; - unsigned lazy = 0; - unsigned lazylength = 0, lazyoffset = 0; - unsigned hashval; - unsigned current_offset, current_length; - unsigned prev_offset; - const unsigned char *lastptr, *foreptr, *backptr; - unsigned hashpos; - - if(windowsize == 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/ - if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/ - - if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH; - - for(pos = inpos; pos < insize; ++pos) { - size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/ - unsigned chainlength = 0; - - hashval = getHash(in, insize, pos); - - if(usezeros && hashval == 0) { - if(numzeros == 0) numzeros = countZeros(in, insize, pos); - else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; - } else { - numzeros = 0; - } - - updateHashChain(hash, wpos, hashval, numzeros); - - /*the length and offset found for the current position*/ - length = 0; - offset = 0; - - hashpos = hash->chain[wpos]; - - lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH]; - - /*search for the longest string*/ - prev_offset = 0; - for(;;) { - if(chainlength++ >= maxchainlength) break; - current_offset = (unsigned)(hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize); - - if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/ - prev_offset = current_offset; - if(current_offset > 0) { - /*test the next characters*/ - foreptr = &in[pos]; - backptr = &in[pos - current_offset]; - - /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/ - if(numzeros >= 3) { - unsigned skip = hash->zeros[hashpos]; - if(skip > numzeros) skip = numzeros; - backptr += skip; - foreptr += skip; - } - - while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/ { - ++backptr; - ++foreptr; - } - current_length = (unsigned)(foreptr - &in[pos]); - - if(current_length > length) { - length = current_length; /*the longest length*/ - offset = current_offset; /*the offset that is related to this longest length*/ - /*jump out once a length of max length is found (speed gain). This also jumps - out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/ - if(current_length >= nicematch) break; - } - } - - if(hashpos == hash->chain[hashpos]) break; - - if(numzeros >= 3 && length > numzeros) { - hashpos = hash->chainz[hashpos]; - if(hash->zeros[hashpos] != numzeros) break; - } else { - hashpos = hash->chain[hashpos]; - /*outdated hash value, happens if particular value was not encountered in whole last window*/ - if(hash->val[hashpos] != (int)hashval) break; - } - } - - if(lazymatching) { - if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH) { - lazy = 1; - lazylength = length; - lazyoffset = offset; - continue; /*try the next byte*/ - } - if(lazy) { - lazy = 0; - if(pos == 0) ERROR_BREAK(81); - if(length > lazylength + 1) { - /*push the previous character as literal*/ - if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/); - } else { - length = lazylength; - offset = lazyoffset; - hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/ - hash->headz[numzeros] = -1; /*idem*/ - --pos; - } - } - } - if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/); - - /*encode it as length/distance pair or literal value*/ - if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/ { - if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); - } else if(length < minmatch || (length == 3 && offset > 4096)) { - /*compensate for the fact that longer offsets have more extra bits, a - length of only 3 may be not worth it then*/ - if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/); - } else { - addLengthDistance(out, length, offset); - for(i = 1; i < length; ++i) { - ++pos; - wpos = pos & (windowsize - 1); - hashval = getHash(in, insize, pos); - if(usezeros && hashval == 0) { - if(numzeros == 0) numzeros = countZeros(in, insize, pos); - else if(pos + numzeros > insize || in[pos + numzeros - 1] != 0) --numzeros; - } else { - numzeros = 0; - } - updateHashChain(hash, wpos, hashval, numzeros); - } - } - } /*end of the loop through each character of input*/ - - return error; -} - -/* /////////////////////////////////////////////////////////////////////////// */ - -static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize) { - /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte, - 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/ - - size_t i, numdeflateblocks = (datasize + 65534u) / 65535u; - unsigned datapos = 0; - for(i = 0; i != numdeflateblocks; ++i) { - unsigned BFINAL, BTYPE, LEN, NLEN; - unsigned char firstbyte; - size_t pos = out->size; - - BFINAL = (i == numdeflateblocks - 1); - BTYPE = 0; - - LEN = 65535; - if(datasize - datapos < 65535u) LEN = (unsigned)datasize - datapos; - NLEN = 65535 - LEN; - - if(!ucvector_resize(out, out->size + LEN + 5)) return 83; /*alloc fail*/ - - firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1u) << 1u) + ((BTYPE & 2u) << 1u)); - out->data[pos + 0] = firstbyte; - out->data[pos + 1] = (unsigned char)(LEN & 255); - out->data[pos + 2] = (unsigned char)(LEN >> 8u); - out->data[pos + 3] = (unsigned char)(NLEN & 255); - out->data[pos + 4] = (unsigned char)(NLEN >> 8u); - lodepng_memcpy(out->data + pos + 5, data + datapos, LEN); - datapos += LEN; - } - - return 0; -} - -/* -write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees. -tree_ll: the tree for lit and len codes. -tree_d: the tree for distance codes. -*/ -static void writeLZ77data(LodePNGBitWriter* writer, const uivector* lz77_encoded, - const HuffmanTree* tree_ll, const HuffmanTree* tree_d) { - size_t i = 0; - for(i = 0; i != lz77_encoded->size; ++i) { - unsigned val = lz77_encoded->data[i]; - writeBitsReversed(writer, tree_ll->codes[val], tree_ll->lengths[val]); - if(val > 256) /*for a length code, 3 more things have to be added*/ { - unsigned length_index = val - FIRST_LENGTH_CODE_INDEX; - unsigned n_length_extra_bits = LENGTHEXTRA[length_index]; - unsigned length_extra_bits = lz77_encoded->data[++i]; - - unsigned distance_code = lz77_encoded->data[++i]; - - unsigned distance_index = distance_code; - unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index]; - unsigned distance_extra_bits = lz77_encoded->data[++i]; - - writeBits(writer, length_extra_bits, n_length_extra_bits); - writeBitsReversed(writer, tree_d->codes[distance_code], tree_d->lengths[distance_code]); - writeBits(writer, distance_extra_bits, n_distance_extra_bits); - } - } -} - -/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/ -static unsigned deflateDynamic(LodePNGBitWriter* writer, Hash* hash, - const unsigned char* data, size_t datapos, size_t dataend, - const LodePNGCompressSettings* settings, unsigned final) { - unsigned error = 0; - - /* - A block is compressed as follows: The PNG data is lz77 encoded, resulting in - literal bytes and length/distance pairs. This is then huffman compressed with - two huffman trees. One huffman tree is used for the lit and len values ("ll"), - another huffman tree is used for the dist values ("d"). These two trees are - stored using their code lengths, and to compress even more these code lengths - are also run-length encoded and huffman compressed. This gives a huffman tree - of code lengths "cl". The code lengths used to describe this third tree are - the code length code lengths ("clcl"). - */ - - /*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/ - uivector lz77_encoded; - HuffmanTree tree_ll; /*tree for lit,len values*/ - HuffmanTree tree_d; /*tree for distance codes*/ - HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/ - unsigned* frequencies_ll = 0; /*frequency of lit,len codes*/ - unsigned* frequencies_d = 0; /*frequency of dist codes*/ - unsigned* frequencies_cl = 0; /*frequency of code length codes*/ - unsigned* bitlen_lld = 0; /*lit,len,dist code lengths (int bits), literally (without repeat codes).*/ - unsigned* bitlen_lld_e = 0; /*bitlen_lld encoded with repeat codes (this is a rudimentary run length compression)*/ - size_t datasize = dataend - datapos; - - /* - If we could call "bitlen_cl" the the code length code lengths ("clcl"), that is the bit lengths of codes to represent - tree_cl in CLCL_ORDER, then due to the huffman compression of huffman tree representations ("two levels"), there are - some analogies: - bitlen_lld is to tree_cl what data is to tree_ll and tree_d. - bitlen_lld_e is to bitlen_lld what lz77_encoded is to data. - bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded. - */ - - unsigned BFINAL = final; - size_t i; - size_t numcodes_ll, numcodes_d, numcodes_lld, numcodes_lld_e, numcodes_cl; - unsigned HLIT, HDIST, HCLEN; - - uivector_init(&lz77_encoded); - HuffmanTree_init(&tree_ll); - HuffmanTree_init(&tree_d); - HuffmanTree_init(&tree_cl); - /* could fit on stack, but >1KB is on the larger side so allocate instead */ - frequencies_ll = (unsigned*)lodepng_malloc(286 * sizeof(*frequencies_ll)); - frequencies_d = (unsigned*)lodepng_malloc(30 * sizeof(*frequencies_d)); - frequencies_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl)); - - if(!frequencies_ll || !frequencies_d || !frequencies_cl) error = 83; /*alloc fail*/ - - /*This while loop never loops due to a break at the end, it is here to - allow breaking out of it to the cleanup phase on error conditions.*/ - while(!error) { - lodepng_memset(frequencies_ll, 0, 286 * sizeof(*frequencies_ll)); - lodepng_memset(frequencies_d, 0, 30 * sizeof(*frequencies_d)); - lodepng_memset(frequencies_cl, 0, NUM_CODE_LENGTH_CODES * sizeof(*frequencies_cl)); - - if(settings->use_lz77) { - error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, - settings->minmatch, settings->nicematch, settings->lazymatching); - if(error) break; - } else { - if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/); - for(i = datapos; i < dataend; ++i) lz77_encoded.data[i - datapos] = data[i]; /*no LZ77, but still will be Huffman compressed*/ - } - - /*Count the frequencies of lit, len and dist codes*/ - for(i = 0; i != lz77_encoded.size; ++i) { - unsigned symbol = lz77_encoded.data[i]; - ++frequencies_ll[symbol]; - if(symbol > 256) { - unsigned dist = lz77_encoded.data[i + 2]; - ++frequencies_d[dist]; - i += 3; - } - } - frequencies_ll[256] = 1; /*there will be exactly 1 end code, at the end of the block*/ - - /*Make both huffman trees, one for the lit and len codes, one for the dist codes*/ - error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll, 257, 286, 15); - if(error) break; - /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/ - error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d, 2, 30, 15); - if(error) break; - - numcodes_ll = LODEPNG_MIN(tree_ll.numcodes, 286); - numcodes_d = LODEPNG_MIN(tree_d.numcodes, 30); - /*store the code lengths of both generated trees in bitlen_lld*/ - numcodes_lld = numcodes_ll + numcodes_d; - bitlen_lld = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld)); - /*numcodes_lld_e never needs more size than bitlen_lld*/ - bitlen_lld_e = (unsigned*)lodepng_malloc(numcodes_lld * sizeof(*bitlen_lld_e)); - if(!bitlen_lld || !bitlen_lld_e) ERROR_BREAK(83); /*alloc fail*/ - numcodes_lld_e = 0; - - for(i = 0; i != numcodes_ll; ++i) bitlen_lld[i] = tree_ll.lengths[i]; - for(i = 0; i != numcodes_d; ++i) bitlen_lld[numcodes_ll + i] = tree_d.lengths[i]; - - /*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times), - 17 (3-10 zeroes), 18 (11-138 zeroes)*/ - for(i = 0; i != numcodes_lld; ++i) { - unsigned j = 0; /*amount of repetitions*/ - while(i + j + 1 < numcodes_lld && bitlen_lld[i + j + 1] == bitlen_lld[i]) ++j; - - if(bitlen_lld[i] == 0 && j >= 2) /*repeat code for zeroes*/ { - ++j; /*include the first zero*/ - if(j <= 10) /*repeat code 17 supports max 10 zeroes*/ { - bitlen_lld_e[numcodes_lld_e++] = 17; - bitlen_lld_e[numcodes_lld_e++] = j - 3; - } else /*repeat code 18 supports max 138 zeroes*/ { - if(j > 138) j = 138; - bitlen_lld_e[numcodes_lld_e++] = 18; - bitlen_lld_e[numcodes_lld_e++] = j - 11; - } - i += (j - 1); - } else if(j >= 3) /*repeat code for value other than zero*/ { - size_t k; - unsigned num = j / 6u, rest = j % 6u; - bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i]; - for(k = 0; k < num; ++k) { - bitlen_lld_e[numcodes_lld_e++] = 16; - bitlen_lld_e[numcodes_lld_e++] = 6 - 3; - } - if(rest >= 3) { - bitlen_lld_e[numcodes_lld_e++] = 16; - bitlen_lld_e[numcodes_lld_e++] = rest - 3; - } - else j -= rest; - i += j; - } else /*too short to benefit from repeat code*/ { - bitlen_lld_e[numcodes_lld_e++] = bitlen_lld[i]; - } - } - - /*generate tree_cl, the huffmantree of huffmantrees*/ - for(i = 0; i != numcodes_lld_e; ++i) { - ++frequencies_cl[bitlen_lld_e[i]]; - /*after a repeat code come the bits that specify the number of repetitions, - those don't need to be in the frequencies_cl calculation*/ - if(bitlen_lld_e[i] >= 16) ++i; - } - - error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl, - NUM_CODE_LENGTH_CODES, NUM_CODE_LENGTH_CODES, 7); - if(error) break; - - /*compute amount of code-length-code-lengths to output*/ - numcodes_cl = NUM_CODE_LENGTH_CODES; - /*trim zeros at the end (using CLCL_ORDER), but minimum size must be 4 (see HCLEN below)*/ - while(numcodes_cl > 4u && tree_cl.lengths[CLCL_ORDER[numcodes_cl - 1u]] == 0) { - numcodes_cl--; - } - - /* - Write everything into the output - - After the BFINAL and BTYPE, the dynamic block consists out of the following: - - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN - - (HCLEN+4)*3 bits code lengths of code length alphabet - - HLIT + 257 code lengths of lit/length alphabet (encoded using the code length - alphabet, + possible repetition codes 16, 17, 18) - - HDIST + 1 code lengths of distance alphabet (encoded using the code length - alphabet, + possible repetition codes 16, 17, 18) - - compressed data - - 256 (end code) - */ - - /*Write block type*/ - writeBits(writer, BFINAL, 1); - writeBits(writer, 0, 1); /*first bit of BTYPE "dynamic"*/ - writeBits(writer, 1, 1); /*second bit of BTYPE "dynamic"*/ - - /*write the HLIT, HDIST and HCLEN values*/ - /*all three sizes take trimmed ending zeroes into account, done either by HuffmanTree_makeFromFrequencies - or in the loop for numcodes_cl above, which saves space. */ - HLIT = (unsigned)(numcodes_ll - 257); - HDIST = (unsigned)(numcodes_d - 1); - HCLEN = (unsigned)(numcodes_cl - 4); - writeBits(writer, HLIT, 5); - writeBits(writer, HDIST, 5); - writeBits(writer, HCLEN, 4); - - /*write the code lengths of the code length alphabet ("bitlen_cl")*/ - for(i = 0; i != numcodes_cl; ++i) writeBits(writer, tree_cl.lengths[CLCL_ORDER[i]], 3); - - /*write the lengths of the lit/len AND the dist alphabet*/ - for(i = 0; i != numcodes_lld_e; ++i) { - writeBitsReversed(writer, tree_cl.codes[bitlen_lld_e[i]], tree_cl.lengths[bitlen_lld_e[i]]); - /*extra bits of repeat codes*/ - if(bitlen_lld_e[i] == 16) writeBits(writer, bitlen_lld_e[++i], 2); - else if(bitlen_lld_e[i] == 17) writeBits(writer, bitlen_lld_e[++i], 3); - else if(bitlen_lld_e[i] == 18) writeBits(writer, bitlen_lld_e[++i], 7); - } - - /*write the compressed data symbols*/ - writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d); - /*error: the length of the end code 256 must be larger than 0*/ - if(tree_ll.lengths[256] == 0) ERROR_BREAK(64); - - /*write the end code*/ - writeBitsReversed(writer, tree_ll.codes[256], tree_ll.lengths[256]); - - break; /*end of error-while*/ - } - - /*cleanup*/ - uivector_cleanup(&lz77_encoded); - HuffmanTree_cleanup(&tree_ll); - HuffmanTree_cleanup(&tree_d); - HuffmanTree_cleanup(&tree_cl); - lodepng_free(frequencies_ll); - lodepng_free(frequencies_d); - lodepng_free(frequencies_cl); - lodepng_free(bitlen_lld); - lodepng_free(bitlen_lld_e); - - return error; -} - -static unsigned deflateFixed(LodePNGBitWriter* writer, Hash* hash, - const unsigned char* data, - size_t datapos, size_t dataend, - const LodePNGCompressSettings* settings, unsigned final) { - HuffmanTree tree_ll; /*tree for literal values and length codes*/ - HuffmanTree tree_d; /*tree for distance codes*/ - - unsigned BFINAL = final; - unsigned error = 0; - size_t i; - - HuffmanTree_init(&tree_ll); - HuffmanTree_init(&tree_d); - - error = generateFixedLitLenTree(&tree_ll); - if(!error) error = generateFixedDistanceTree(&tree_d); - - if(!error) { - writeBits(writer, BFINAL, 1); - writeBits(writer, 1, 1); /*first bit of BTYPE*/ - writeBits(writer, 0, 1); /*second bit of BTYPE*/ - - if(settings->use_lz77) /*LZ77 encoded*/ { - uivector lz77_encoded; - uivector_init(&lz77_encoded); - error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize, - settings->minmatch, settings->nicematch, settings->lazymatching); - if(!error) writeLZ77data(writer, &lz77_encoded, &tree_ll, &tree_d); - uivector_cleanup(&lz77_encoded); - } else /*no LZ77, but still will be Huffman compressed*/ { - for(i = datapos; i < dataend; ++i) { - writeBitsReversed(writer, tree_ll.codes[data[i]], tree_ll.lengths[data[i]]); - } - } - /*add END code*/ - if(!error) writeBitsReversed(writer,tree_ll.codes[256], tree_ll.lengths[256]); - } - - /*cleanup*/ - HuffmanTree_cleanup(&tree_ll); - HuffmanTree_cleanup(&tree_d); - - return error; -} - -static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize, - const LodePNGCompressSettings* settings) { - unsigned error = 0; - size_t i, blocksize, numdeflateblocks; - Hash hash; - LodePNGBitWriter writer; - - LodePNGBitWriter_init(&writer, out); - - if(settings->btype > 2) return 61; - else if(settings->btype == 0) return deflateNoCompression(out, in, insize); - else if(settings->btype == 1) blocksize = insize; - else /*if(settings->btype == 2)*/ { - /*on PNGs, deflate blocks of 65-262k seem to give most dense encoding*/ - blocksize = insize / 8u + 8; - if(blocksize < 65536) blocksize = 65536; - if(blocksize > 262144) blocksize = 262144; - } - - numdeflateblocks = (insize + blocksize - 1) / blocksize; - if(numdeflateblocks == 0) numdeflateblocks = 1; - - error = hash_init(&hash, settings->windowsize); - - if(!error) { - for(i = 0; i != numdeflateblocks && !error; ++i) { - unsigned final = (i == numdeflateblocks - 1); - size_t start = i * blocksize; - size_t end = start + blocksize; - if(end > insize) end = insize; - - if(settings->btype == 1) error = deflateFixed(&writer, &hash, in, start, end, settings, final); - else if(settings->btype == 2) error = deflateDynamic(&writer, &hash, in, start, end, settings, final); - } - } - - hash_cleanup(&hash); - - return error; -} - -unsigned lodepng_deflate(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGCompressSettings* settings) { - ucvector v = ucvector_init(*out, *outsize); - unsigned error = lodepng_deflatev(&v, in, insize, settings); - *out = v.data; - *outsize = v.size; - return error; -} - -static unsigned deflate(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGCompressSettings* settings) { - if(settings->custom_deflate) { - unsigned error = settings->custom_deflate(out, outsize, in, insize, settings); - /*the custom deflate is allowed to have its own error codes, however, we translate it to code 111*/ - return error ? 111 : 0; - } else { - return lodepng_deflate(out, outsize, in, insize, settings); - } -} - -#endif /*LODEPNG_COMPILE_DECODER*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Adler32 / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len) { - unsigned s1 = adler & 0xffffu; - unsigned s2 = (adler >> 16u) & 0xffffu; - - while(len != 0u) { - unsigned i; - /*at least 5552 sums can be done before the sums overflow, saving a lot of module divisions*/ - unsigned amount = len > 5552u ? 5552u : len; - len -= amount; - for(i = 0; i != amount; ++i) { - s1 += (*data++); - s2 += s1; - } - s1 %= 65521u; - s2 %= 65521u; - } - - return (s2 << 16u) | s1; -} - -/*Return the adler32 of the bytes data[0..len-1]*/ -static unsigned adler32(const unsigned char* data, unsigned len) { - return update_adler32(1u, data, len); -} - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Zlib / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_DECODER - -static unsigned lodepng_zlib_decompressv(ucvector* out, - const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings) { - unsigned error = 0; - unsigned CM, CINFO, FDICT; - - if(insize < 2) return 53; /*error, size of zlib data too small*/ - /*read information from zlib header*/ - if((in[0] * 256 + in[1]) % 31 != 0) { - /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/ - return 24; - } - - CM = in[0] & 15; - CINFO = (in[0] >> 4) & 15; - /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/ - FDICT = (in[1] >> 5) & 1; - /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/ - - if(CM != 8 || CINFO > 7) { - /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/ - return 25; - } - if(FDICT != 0) { - /*error: the specification of PNG says about the zlib stream: - "The additional flags shall not specify a preset dictionary."*/ - return 26; - } - - error = inflatev(out, in + 2, insize - 2, settings); - if(error) return error; - - if(!settings->ignore_adler32) { - unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]); - unsigned checksum = adler32(out->data, (unsigned)(out->size)); - if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/ - } - - return 0; /*no error*/ -} - - -unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, - size_t insize, const LodePNGDecompressSettings* settings) { - ucvector v = ucvector_init(*out, *outsize); - unsigned error = lodepng_zlib_decompressv(&v, in, insize, settings); - *out = v.data; - *outsize = v.size; - return error; -} - -/*expected_size is expected output size, to avoid intermediate allocations. Set to 0 if not known. */ -static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size, - const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { - unsigned error; - if(settings->custom_zlib) { - error = settings->custom_zlib(out, outsize, in, insize, settings); - if(error) { - /*the custom zlib is allowed to have its own error codes, however, we translate it to code 110*/ - error = 110; - /*if there's a max output size, and the custom zlib returned error, then indicate that error instead*/ - if(settings->max_output_size && *outsize > settings->max_output_size) error = 109; - } - } else { - ucvector v = ucvector_init(*out, *outsize); - if(expected_size) { - /*reserve the memory to avoid intermediate reallocations*/ - ucvector_resize(&v, *outsize + expected_size); - v.size = *outsize; - } - error = lodepng_zlib_decompressv(&v, in, insize, settings); - *out = v.data; - *outsize = v.size; - } - return error; -} - -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER - -unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, - size_t insize, const LodePNGCompressSettings* settings) { - size_t i; - unsigned error; - unsigned char* deflatedata = 0; - size_t deflatesize = 0; - - error = deflate(&deflatedata, &deflatesize, in, insize, settings); - - *out = NULL; - *outsize = 0; - if(!error) { - *outsize = deflatesize + 6; - *out = (unsigned char*)lodepng_malloc(*outsize); - if(!*out) error = 83; /*alloc fail*/ - } - - if(!error) { - unsigned ADLER32 = adler32(in, (unsigned)insize); - /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/ - unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/ - unsigned FLEVEL = 0; - unsigned FDICT = 0; - unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64; - unsigned FCHECK = 31 - CMFFLG % 31; - CMFFLG += FCHECK; - - (*out)[0] = (unsigned char)(CMFFLG >> 8); - (*out)[1] = (unsigned char)(CMFFLG & 255); - for(i = 0; i != deflatesize; ++i) (*out)[i + 2] = deflatedata[i]; - lodepng_set32bitInt(&(*out)[*outsize - 4], ADLER32); - } - - lodepng_free(deflatedata); - return error; -} - -/* compress using the default or custom zlib function */ -static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, - size_t insize, const LodePNGCompressSettings* settings) { - if(settings->custom_zlib) { - unsigned error = settings->custom_zlib(out, outsize, in, insize, settings); - /*the custom zlib is allowed to have its own error codes, however, we translate it to code 111*/ - return error ? 111 : 0; - } else { - return lodepng_zlib_compress(out, outsize, in, insize, settings); - } -} - -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#else /*no LODEPNG_COMPILE_ZLIB*/ - -#ifdef LODEPNG_COMPILE_DECODER -static unsigned zlib_decompress(unsigned char** out, size_t* outsize, size_t expected_size, - const unsigned char* in, size_t insize, const LodePNGDecompressSettings* settings) { - if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ - (void)expected_size; - return settings->custom_zlib(out, outsize, in, insize, settings); -} -#endif /*LODEPNG_COMPILE_DECODER*/ -#ifdef LODEPNG_COMPILE_ENCODER -static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, - size_t insize, const LodePNGCompressSettings* settings) { - if(!settings->custom_zlib) return 87; /*no custom zlib function provided */ - return settings->custom_zlib(out, outsize, in, insize, settings); -} -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#endif /*LODEPNG_COMPILE_ZLIB*/ - -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_ENCODER - -/*this is a good tradeoff between speed and compression ratio*/ -#define DEFAULT_WINDOWSIZE 2048 - -void lodepng_compress_settings_init(LodePNGCompressSettings* settings) { - /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/ - settings->btype = 2; - settings->use_lz77 = 1; - settings->windowsize = DEFAULT_WINDOWSIZE; - settings->minmatch = 3; - settings->nicematch = 128; - settings->lazymatching = 1; - - settings->custom_zlib = 0; - settings->custom_deflate = 0; - settings->custom_context = 0; -} - -const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0}; - - -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#ifdef LODEPNG_COMPILE_DECODER - -void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings) { - settings->ignore_adler32 = 0; - settings->ignore_nlen = 0; - settings->max_output_size = 0; - - settings->custom_zlib = 0; - settings->custom_inflate = 0; - settings->custom_context = 0; -} - -const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0, 0, 0}; - -#endif /*LODEPNG_COMPILE_DECODER*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* // End of Zlib related code. Begin of PNG related code. // */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_PNG - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / CRC32 / */ -/* ////////////////////////////////////////////////////////////////////////// */ - - -#ifndef LODEPNG_NO_COMPILE_CRC -/* CRC polynomial: 0xedb88320 */ -static unsigned lodepng_crc32_table[256] = { - 0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u, 3915621685u, 2657392035u, - 249268274u, 2044508324u, 3772115230u, 2547177864u, 162941995u, 2125561021u, 3887607047u, 2428444049u, - 498536548u, 1789927666u, 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u, - 325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u, 4195302755u, 2366115317u, - 997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u, - 901097722u, 1119000684u, 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u, - 651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u, 3485111705u, 3099436303u, - 671266974u, 1594198024u, 3322730930u, 2970347812u, 795835527u, 1483230225u, 3244367275u, 3060149565u, - 1994146192u, 31158534u, 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u, - 2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u, 2439277719u, 3865271297u, - 1802195444u, 476864866u, 2238001368u, 4066508878u, 1812370925u, 453092731u, 2181625025u, 4111451223u, - 1706088902u, 314042704u, 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u, - 1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u, - 1131014506u, 879679996u, 2909243462u, 3663771856u, 1141124467u, 855842277u, 2852801631u, 3708648649u, - 1342533948u, 654459306u, 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u, - 1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u, 3082640443u, 3233442989u, - 3988292384u, 2596254646u, 62317068u, 1957810842u, 3939845945u, 2647816111u, 81470997u, 1943803523u, - 3814918930u, 2489596804u, 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u, - 4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u, 426522225u, 1852507879u, - 4275313526u, 2312317920u, 282753626u, 1742555852u, 4189708143u, 2394877945u, 397917763u, 1622183637u, - 3604390888u, 2714866558u, 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u, - 3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u, 829329135u, 1181335161u, - 3412177804u, 3160834842u, 628085408u, 1382605366u, 3423369109u, 3138078467u, 570562233u, 1426400815u, - 3317316542u, 2998733608u, 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u, - 2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u, 1913087877u, 83908371u, - 2512341634u, 3803740692u, 2075208622u, 213261112u, 2463272603u, 3855990285u, 2094854071u, 198958881u, - 2262029012u, 4057260610u, 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u, - 2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u, 1634467795u, 376229701u, - 2685067896u, 3608007406u, 1308918612u, 956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u, - 2932959818u, 3654703836u, 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u, - 3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u, 1423857449u, 601450431u, - 3009837614u, 3294710456u, 1567103746u, 711928724u, 3020668471u, 3272380065u, 1510334235u, 755167117u -}; - -/*Return the CRC of the bytes buf[0..len-1].*/ -unsigned lodepng_crc32(const unsigned char* data, size_t length) { - unsigned r = 0xffffffffu; - size_t i; - for(i = 0; i < length; ++i) { - r = lodepng_crc32_table[(r ^ data[i]) & 0xffu] ^ (r >> 8u); - } - return r ^ 0xffffffffu; -} -#else /* !LODEPNG_NO_COMPILE_CRC */ -unsigned lodepng_crc32(const unsigned char* data, size_t length); -#endif /* !LODEPNG_NO_COMPILE_CRC */ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Reading and writing PNG color channel bits / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -/* The color channel bits of less-than-8-bit pixels are read with the MSB of bytes first, -so LodePNGBitWriter and LodePNGBitReader can't be used for those. */ - -static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream) { - unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1); - ++(*bitpointer); - return result; -} - -/* TODO: make this faster */ -static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits) { - unsigned result = 0; - size_t i; - for(i = 0 ; i < nbits; ++i) { - result <<= 1u; - result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream); - } - return result; -} - -static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit) { - /*the current bit in bitstream may be 0 or 1 for this to work*/ - if(bit == 0) bitstream[(*bitpointer) >> 3u] &= (unsigned char)(~(1u << (7u - ((*bitpointer) & 7u)))); - else bitstream[(*bitpointer) >> 3u] |= (1u << (7u - ((*bitpointer) & 7u))); - ++(*bitpointer); -} - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / PNG chunks / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -unsigned lodepng_chunk_length(const unsigned char* chunk) { - return lodepng_read32bitInt(&chunk[0]); -} - -void lodepng_chunk_type(char type[5], const unsigned char* chunk) { - unsigned i; - for(i = 0; i != 4; ++i) type[i] = (char)chunk[4 + i]; - type[4] = 0; /*null termination char*/ -} - -unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type) { - if(lodepng_strlen(type) != 4) return 0; - return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]); -} - -unsigned char lodepng_chunk_ancillary(const unsigned char* chunk) { - return((chunk[4] & 32) != 0); -} - -unsigned char lodepng_chunk_private(const unsigned char* chunk) { - return((chunk[6] & 32) != 0); -} - -unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk) { - return((chunk[7] & 32) != 0); -} - -unsigned char* lodepng_chunk_data(unsigned char* chunk) { - return &chunk[8]; -} - -const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk) { - return &chunk[8]; -} - -unsigned lodepng_chunk_check_crc(const unsigned char* chunk) { - unsigned length = lodepng_chunk_length(chunk); - unsigned CRC = lodepng_read32bitInt(&chunk[length + 8]); - /*the CRC is taken of the data and the 4 chunk type letters, not the length*/ - unsigned checksum = lodepng_crc32(&chunk[4], length + 4); - if(CRC != checksum) return 1; - else return 0; -} - -void lodepng_chunk_generate_crc(unsigned char* chunk) { - unsigned length = lodepng_chunk_length(chunk); - unsigned CRC = lodepng_crc32(&chunk[4], length + 4); - lodepng_set32bitInt(chunk + 8 + length, CRC); -} - -unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end) { - if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/ - if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 - && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { - /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ - return chunk + 8; - } else { - size_t total_chunk_length; - unsigned char* result; - if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end; - result = chunk + total_chunk_length; - if(result < chunk) return end; /*pointer overflow*/ - return result; - } -} - -const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end) { - if(chunk >= end || end - chunk < 12) return end; /*too small to contain a chunk*/ - if(chunk[0] == 0x89 && chunk[1] == 0x50 && chunk[2] == 0x4e && chunk[3] == 0x47 - && chunk[4] == 0x0d && chunk[5] == 0x0a && chunk[6] == 0x1a && chunk[7] == 0x0a) { - /* Is PNG magic header at start of PNG file. Jump to first actual chunk. */ - return chunk + 8; - } else { - size_t total_chunk_length; - const unsigned char* result; - if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return end; - result = chunk + total_chunk_length; - if(result < chunk) return end; /*pointer overflow*/ - return result; - } -} - -unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]) { - for(;;) { - if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */ - if(lodepng_chunk_type_equals(chunk, type)) return chunk; - chunk = lodepng_chunk_next(chunk, end); - } -} - -const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]) { - for(;;) { - if(chunk >= end || end - chunk < 12) return 0; /* past file end: chunk + 12 > end */ - if(lodepng_chunk_type_equals(chunk, type)) return chunk; - chunk = lodepng_chunk_next_const(chunk, end); - } -} - -unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk) { - unsigned i; - size_t total_chunk_length, new_length; - unsigned char *chunk_start, *new_buffer; - - if(lodepng_addofl(lodepng_chunk_length(chunk), 12, &total_chunk_length)) return 77; - if(lodepng_addofl(*outsize, total_chunk_length, &new_length)) return 77; - - new_buffer = (unsigned char*)lodepng_realloc(*out, new_length); - if(!new_buffer) return 83; /*alloc fail*/ - (*out) = new_buffer; - (*outsize) = new_length; - chunk_start = &(*out)[new_length - total_chunk_length]; - - for(i = 0; i != total_chunk_length; ++i) chunk_start[i] = chunk[i]; - - return 0; -} - -/*Sets length and name and allocates the space for data and crc but does not -set data or crc yet. Returns the start of the chunk in chunk. The start of -the data is at chunk + 8. To finalize chunk, add the data, then use -lodepng_chunk_generate_crc */ -static unsigned lodepng_chunk_init(unsigned char** chunk, - ucvector* out, - unsigned length, const char* type) { - size_t new_length = out->size; - if(lodepng_addofl(new_length, length, &new_length)) return 77; - if(lodepng_addofl(new_length, 12, &new_length)) return 77; - if(!ucvector_resize(out, new_length)) return 83; /*alloc fail*/ - *chunk = out->data + new_length - length - 12u; - - /*1: length*/ - lodepng_set32bitInt(*chunk, length); - - /*2: chunk name (4 letters)*/ - lodepng_memcpy(*chunk + 4, type, 4); - - return 0; -} - -/* like lodepng_chunk_create but with custom allocsize */ -static unsigned lodepng_chunk_createv(ucvector* out, - unsigned length, const char* type, const unsigned char* data) { - unsigned char* chunk; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, length, type)); - - /*3: the data*/ - lodepng_memcpy(chunk + 8, data, length); - - /*4: CRC (of the chunkname characters and the data)*/ - lodepng_chunk_generate_crc(chunk); - - return 0; -} - -unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, - unsigned length, const char* type, const unsigned char* data) { - ucvector v = ucvector_init(*out, *outsize); - unsigned error = lodepng_chunk_createv(&v, length, type, data); - *out = v.data; - *outsize = v.size; - return error; -} - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / Color types, channels, bits / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -/*checks if the colortype is valid and the bitdepth bd is allowed for this colortype. -Return value is a LodePNG error code.*/ -static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) { - switch(colortype) { - case LCT_GREY: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; - case LCT_RGB: if(!( bd == 8 || bd == 16)) return 37; break; - case LCT_PALETTE: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break; - case LCT_GREY_ALPHA: if(!( bd == 8 || bd == 16)) return 37; break; - case LCT_RGBA: if(!( bd == 8 || bd == 16)) return 37; break; - case LCT_MAX_OCTET_VALUE: return 31; /* invalid color type */ - default: return 31; /* invalid color type */ - } - return 0; /*allowed color type / bits combination*/ -} - -static unsigned getNumColorChannels(LodePNGColorType colortype) { - switch(colortype) { - case LCT_GREY: return 1; - case LCT_RGB: return 3; - case LCT_PALETTE: return 1; - case LCT_GREY_ALPHA: return 2; - case LCT_RGBA: return 4; - case LCT_MAX_OCTET_VALUE: return 0; /* invalid color type */ - default: return 0; /*invalid color type*/ - } -} - -static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth) { - /*bits per pixel is amount of channels * bits per channel*/ - return getNumColorChannels(colortype) * bitdepth; -} - -/* ////////////////////////////////////////////////////////////////////////// */ - -void lodepng_color_mode_init(LodePNGColorMode* info) { - info->key_defined = 0; - info->key_r = info->key_g = info->key_b = 0; - info->colortype = LCT_RGBA; - info->bitdepth = 8; - info->palette = 0; - info->palettesize = 0; -} - -/*allocates palette memory if needed, and initializes all colors to black*/ -static void lodepng_color_mode_alloc_palette(LodePNGColorMode* info) { - size_t i; - /*if the palette is already allocated, it will have size 1024 so no reallocation needed in that case*/ - /*the palette must have room for up to 256 colors with 4 bytes each.*/ - if(!info->palette) info->palette = (unsigned char*)lodepng_malloc(1024); - if(!info->palette) return; /*alloc fail*/ - for(i = 0; i != 256; ++i) { - /*Initialize all unused colors with black, the value used for invalid palette indices. - This is an error according to the PNG spec, but common PNG decoders make it black instead. - That makes color conversion slightly faster due to no error handling needed.*/ - info->palette[i * 4 + 0] = 0; - info->palette[i * 4 + 1] = 0; - info->palette[i * 4 + 2] = 0; - info->palette[i * 4 + 3] = 255; - } -} - -void lodepng_color_mode_cleanup(LodePNGColorMode* info) { - lodepng_palette_clear(info); -} - -unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source) { - lodepng_color_mode_cleanup(dest); - lodepng_memcpy(dest, source, sizeof(LodePNGColorMode)); - if(source->palette) { - dest->palette = (unsigned char*)lodepng_malloc(1024); - if(!dest->palette && source->palettesize) return 83; /*alloc fail*/ - lodepng_memcpy(dest->palette, source->palette, source->palettesize * 4); - } - return 0; -} - -LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth) { - LodePNGColorMode result; - lodepng_color_mode_init(&result); - result.colortype = colortype; - result.bitdepth = bitdepth; - return result; -} - -static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b) { - size_t i; - if(a->colortype != b->colortype) return 0; - if(a->bitdepth != b->bitdepth) return 0; - if(a->key_defined != b->key_defined) return 0; - if(a->key_defined) { - if(a->key_r != b->key_r) return 0; - if(a->key_g != b->key_g) return 0; - if(a->key_b != b->key_b) return 0; - } - if(a->palettesize != b->palettesize) return 0; - for(i = 0; i != a->palettesize * 4; ++i) { - if(a->palette[i] != b->palette[i]) return 0; - } - return 1; -} - -void lodepng_palette_clear(LodePNGColorMode* info) { - if(info->palette) lodepng_free(info->palette); - info->palette = 0; - info->palettesize = 0; -} - -unsigned lodepng_palette_add(LodePNGColorMode* info, - unsigned char r, unsigned char g, unsigned char b, unsigned char a) { - if(!info->palette) /*allocate palette if empty*/ { - lodepng_color_mode_alloc_palette(info); - if(!info->palette) return 83; /*alloc fail*/ - } - if(info->palettesize >= 256) { - return 108; /*too many palette values*/ - } - info->palette[4 * info->palettesize + 0] = r; - info->palette[4 * info->palettesize + 1] = g; - info->palette[4 * info->palettesize + 2] = b; - info->palette[4 * info->palettesize + 3] = a; - ++info->palettesize; - return 0; -} - -/*calculate bits per pixel out of colortype and bitdepth*/ -unsigned lodepng_get_bpp(const LodePNGColorMode* info) { - return lodepng_get_bpp_lct(info->colortype, info->bitdepth); -} - -unsigned lodepng_get_channels(const LodePNGColorMode* info) { - return getNumColorChannels(info->colortype); -} - -unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info) { - return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA; -} - -unsigned lodepng_is_alpha_type(const LodePNGColorMode* info) { - return (info->colortype & 4) != 0; /*4 or 6*/ -} - -unsigned lodepng_is_palette_type(const LodePNGColorMode* info) { - return info->colortype == LCT_PALETTE; -} - -unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info) { - size_t i; - for(i = 0; i != info->palettesize; ++i) { - if(info->palette[i * 4 + 3] < 255) return 1; - } - return 0; -} - -unsigned lodepng_can_have_alpha(const LodePNGColorMode* info) { - return info->key_defined - || lodepng_is_alpha_type(info) - || lodepng_has_palette_alpha(info); -} - -static size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { - size_t bpp = lodepng_get_bpp_lct(colortype, bitdepth); - size_t n = (size_t)w * (size_t)h; - return ((n / 8u) * bpp) + ((n & 7u) * bpp + 7u) / 8u; -} - -size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color) { - return lodepng_get_raw_size_lct(w, h, color->colortype, color->bitdepth); -} - - -#ifdef LODEPNG_COMPILE_PNG - -/*in an idat chunk, each scanline is a multiple of 8 bits, unlike the lodepng output buffer, -and in addition has one extra byte per line: the filter byte. So this gives a larger -result than lodepng_get_raw_size. Set h to 1 to get the size of 1 row including filter byte. */ -static size_t lodepng_get_raw_size_idat(unsigned w, unsigned h, unsigned bpp) { - /* + 1 for the filter byte, and possibly plus padding bits per line. */ - /* Ignoring casts, the expression is equal to (w * bpp + 7) / 8 + 1, but avoids overflow of w * bpp */ - size_t line = ((size_t)(w / 8u) * bpp) + 1u + ((w & 7u) * bpp + 7u) / 8u; - return (size_t)h * line; -} - -#ifdef LODEPNG_COMPILE_DECODER -/*Safely checks whether size_t overflow can be caused due to amount of pixels. -This check is overcautious rather than precise. If this check indicates no overflow, -you can safely compute in a size_t (but not an unsigned): --(size_t)w * (size_t)h * 8 --amount of bytes in IDAT (including filter, padding and Adam7 bytes) --amount of bytes in raw color model -Returns 1 if overflow possible, 0 if not. -*/ -static int lodepng_pixel_overflow(unsigned w, unsigned h, - const LodePNGColorMode* pngcolor, const LodePNGColorMode* rawcolor) { - size_t bpp = LODEPNG_MAX(lodepng_get_bpp(pngcolor), lodepng_get_bpp(rawcolor)); - size_t numpixels, total; - size_t line; /* bytes per line in worst case */ - - if(lodepng_mulofl((size_t)w, (size_t)h, &numpixels)) return 1; - if(lodepng_mulofl(numpixels, 8, &total)) return 1; /* bit pointer with 8-bit color, or 8 bytes per channel color */ - - /* Bytes per scanline with the expression "(w / 8u) * bpp) + ((w & 7u) * bpp + 7u) / 8u" */ - if(lodepng_mulofl((size_t)(w / 8u), bpp, &line)) return 1; - if(lodepng_addofl(line, ((w & 7u) * bpp + 7u) / 8u, &line)) return 1; - - if(lodepng_addofl(line, 5, &line)) return 1; /* 5 bytes overhead per line: 1 filterbyte, 4 for Adam7 worst case */ - if(lodepng_mulofl(line, h, &total)) return 1; /* Total bytes in worst case */ - - return 0; /* no overflow */ -} -#endif /*LODEPNG_COMPILE_DECODER*/ -#endif /*LODEPNG_COMPILE_PNG*/ - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - -static void LodePNGUnknownChunks_init(LodePNGInfo* info) { - unsigned i; - for(i = 0; i != 3; ++i) info->unknown_chunks_data[i] = 0; - for(i = 0; i != 3; ++i) info->unknown_chunks_size[i] = 0; -} - -static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info) { - unsigned i; - for(i = 0; i != 3; ++i) lodepng_free(info->unknown_chunks_data[i]); -} - -static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src) { - unsigned i; - - LodePNGUnknownChunks_cleanup(dest); - - for(i = 0; i != 3; ++i) { - size_t j; - dest->unknown_chunks_size[i] = src->unknown_chunks_size[i]; - dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]); - if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/ - for(j = 0; j < src->unknown_chunks_size[i]; ++j) { - dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j]; - } - } - - return 0; -} - -/******************************************************************************/ - -static void LodePNGText_init(LodePNGInfo* info) { - info->text_num = 0; - info->text_keys = NULL; - info->text_strings = NULL; -} - -static void LodePNGText_cleanup(LodePNGInfo* info) { - size_t i; - for(i = 0; i != info->text_num; ++i) { - string_cleanup(&info->text_keys[i]); - string_cleanup(&info->text_strings[i]); - } - lodepng_free(info->text_keys); - lodepng_free(info->text_strings); -} - -static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { - size_t i = 0; - dest->text_keys = NULL; - dest->text_strings = NULL; - dest->text_num = 0; - for(i = 0; i != source->text_num; ++i) { - CERROR_TRY_RETURN(lodepng_add_text(dest, source->text_keys[i], source->text_strings[i])); - } - return 0; -} - -static unsigned lodepng_add_text_sized(LodePNGInfo* info, const char* key, const char* str, size_t size) { - char** new_keys = (char**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1))); - char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1))); - - if(new_keys) info->text_keys = new_keys; - if(new_strings) info->text_strings = new_strings; - - if(!new_keys || !new_strings) return 83; /*alloc fail*/ - - ++info->text_num; - info->text_keys[info->text_num - 1] = alloc_string(key); - info->text_strings[info->text_num - 1] = alloc_string_sized(str, size); - if(!info->text_keys[info->text_num - 1] || !info->text_strings[info->text_num - 1]) return 83; /*alloc fail*/ - - return 0; -} - -unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str) { - return lodepng_add_text_sized(info, key, str, lodepng_strlen(str)); -} - -void lodepng_clear_text(LodePNGInfo* info) { - LodePNGText_cleanup(info); -} - -/******************************************************************************/ - -static void LodePNGIText_init(LodePNGInfo* info) { - info->itext_num = 0; - info->itext_keys = NULL; - info->itext_langtags = NULL; - info->itext_transkeys = NULL; - info->itext_strings = NULL; -} - -static void LodePNGIText_cleanup(LodePNGInfo* info) { - size_t i; - for(i = 0; i != info->itext_num; ++i) { - string_cleanup(&info->itext_keys[i]); - string_cleanup(&info->itext_langtags[i]); - string_cleanup(&info->itext_transkeys[i]); - string_cleanup(&info->itext_strings[i]); - } - lodepng_free(info->itext_keys); - lodepng_free(info->itext_langtags); - lodepng_free(info->itext_transkeys); - lodepng_free(info->itext_strings); -} - -static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source) { - size_t i = 0; - dest->itext_keys = NULL; - dest->itext_langtags = NULL; - dest->itext_transkeys = NULL; - dest->itext_strings = NULL; - dest->itext_num = 0; - for(i = 0; i != source->itext_num; ++i) { - CERROR_TRY_RETURN(lodepng_add_itext(dest, source->itext_keys[i], source->itext_langtags[i], - source->itext_transkeys[i], source->itext_strings[i])); - } - return 0; -} - -void lodepng_clear_itext(LodePNGInfo* info) { - LodePNGIText_cleanup(info); -} - -static unsigned lodepng_add_itext_sized(LodePNGInfo* info, const char* key, const char* langtag, - const char* transkey, const char* str, size_t size) { - char** new_keys = (char**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1))); - char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1))); - char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1))); - char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1))); - - if(new_keys) info->itext_keys = new_keys; - if(new_langtags) info->itext_langtags = new_langtags; - if(new_transkeys) info->itext_transkeys = new_transkeys; - if(new_strings) info->itext_strings = new_strings; - - if(!new_keys || !new_langtags || !new_transkeys || !new_strings) return 83; /*alloc fail*/ - - ++info->itext_num; - - info->itext_keys[info->itext_num - 1] = alloc_string(key); - info->itext_langtags[info->itext_num - 1] = alloc_string(langtag); - info->itext_transkeys[info->itext_num - 1] = alloc_string(transkey); - info->itext_strings[info->itext_num - 1] = alloc_string_sized(str, size); - - return 0; -} - -unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag, - const char* transkey, const char* str) { - return lodepng_add_itext_sized(info, key, langtag, transkey, str, lodepng_strlen(str)); -} - -/* same as set but does not delete */ -static unsigned lodepng_assign_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) { - if(profile_size == 0) return 100; /*invalid ICC profile size*/ - - info->iccp_name = alloc_string(name); - info->iccp_profile = (unsigned char*)lodepng_malloc(profile_size); - - if(!info->iccp_name || !info->iccp_profile) return 83; /*alloc fail*/ - - lodepng_memcpy(info->iccp_profile, profile, profile_size); - info->iccp_profile_size = profile_size; - - return 0; /*ok*/ -} - -unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size) { - if(info->iccp_name) lodepng_clear_icc(info); - info->iccp_defined = 1; - - return lodepng_assign_icc(info, name, profile, profile_size); -} - -void lodepng_clear_icc(LodePNGInfo* info) { - string_cleanup(&info->iccp_name); - lodepng_free(info->iccp_profile); - info->iccp_profile = NULL; - info->iccp_profile_size = 0; - info->iccp_defined = 0; -} -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -void lodepng_info_init(LodePNGInfo* info) { - lodepng_color_mode_init(&info->color); - info->interlace_method = 0; - info->compression_method = 0; - info->filter_method = 0; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - info->background_defined = 0; - info->background_r = info->background_g = info->background_b = 0; - - LodePNGText_init(info); - LodePNGIText_init(info); - - info->time_defined = 0; - info->phys_defined = 0; - - info->gama_defined = 0; - info->chrm_defined = 0; - info->srgb_defined = 0; - info->iccp_defined = 0; - info->iccp_name = NULL; - info->iccp_profile = NULL; - - LodePNGUnknownChunks_init(info); -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} - -void lodepng_info_cleanup(LodePNGInfo* info) { - lodepng_color_mode_cleanup(&info->color); -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - LodePNGText_cleanup(info); - LodePNGIText_cleanup(info); - - lodepng_clear_icc(info); - - LodePNGUnknownChunks_cleanup(info); -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} - -unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source) { - lodepng_info_cleanup(dest); - lodepng_memcpy(dest, source, sizeof(LodePNGInfo)); - lodepng_color_mode_init(&dest->color); - CERROR_TRY_RETURN(lodepng_color_mode_copy(&dest->color, &source->color)); - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - CERROR_TRY_RETURN(LodePNGText_copy(dest, source)); - CERROR_TRY_RETURN(LodePNGIText_copy(dest, source)); - if(source->iccp_defined) { - CERROR_TRY_RETURN(lodepng_assign_icc(dest, source->iccp_name, source->iccp_profile, source->iccp_profile_size)); - } - - LodePNGUnknownChunks_init(dest); - CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source)); -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - return 0; -} - -/* ////////////////////////////////////////////////////////////////////////// */ - -/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/ -static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in) { - unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/ - /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/ - unsigned p = index & m; - in &= (1u << bits) - 1u; /*filter out any other bits of the input value*/ - in = in << (bits * (m - p)); - if(p == 0) out[index * bits / 8u] = in; - else out[index * bits / 8u] |= in; -} - -typedef struct ColorTree ColorTree; - -/* -One node of a color tree -This is the data structure used to count the number of unique colors and to get a palette -index for a color. It's like an octree, but because the alpha channel is used too, each -node has 16 instead of 8 children. -*/ -struct ColorTree { - ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/ - int index; /*the payload. Only has a meaningful value if this is in the last level*/ -}; - -static void color_tree_init(ColorTree* tree) { - lodepng_memset(tree->children, 0, 16 * sizeof(*tree->children)); - tree->index = -1; -} - -static void color_tree_cleanup(ColorTree* tree) { - int i; - for(i = 0; i != 16; ++i) { - if(tree->children[i]) { - color_tree_cleanup(tree->children[i]); - lodepng_free(tree->children[i]); - } - } -} - -/*returns -1 if color not present, its index otherwise*/ -static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { - int bit = 0; - for(bit = 0; bit < 8; ++bit) { - int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); - if(!tree->children[i]) return -1; - else tree = tree->children[i]; - } - return tree ? tree->index : -1; -} - -#ifdef LODEPNG_COMPILE_ENCODER -static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a) { - return color_tree_get(tree, r, g, b, a) >= 0; -} -#endif /*LODEPNG_COMPILE_ENCODER*/ - -/*color is not allowed to already exist. -Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist") -Returns error code, or 0 if ok*/ -static unsigned color_tree_add(ColorTree* tree, - unsigned char r, unsigned char g, unsigned char b, unsigned char a, unsigned index) { - int bit; - for(bit = 0; bit < 8; ++bit) { - int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1); - if(!tree->children[i]) { - tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree)); - if(!tree->children[i]) return 83; /*alloc fail*/ - color_tree_init(tree->children[i]); - } - tree = tree->children[i]; - } - tree->index = (int)index; - return 0; -} - -/*put a pixel, given its RGBA color, into image of any color type*/ -static unsigned rgba8ToPixel(unsigned char* out, size_t i, - const LodePNGColorMode* mode, ColorTree* tree /*for palette*/, - unsigned char r, unsigned char g, unsigned char b, unsigned char a) { - if(mode->colortype == LCT_GREY) { - unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ - if(mode->bitdepth == 8) out[i] = gray; - else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = gray; - else { - /*take the most significant bits of gray*/ - gray = ((unsigned)gray >> (8u - mode->bitdepth)) & ((1u << mode->bitdepth) - 1u); - addColorBits(out, i, mode->bitdepth, gray); - } - } else if(mode->colortype == LCT_RGB) { - if(mode->bitdepth == 8) { - out[i * 3 + 0] = r; - out[i * 3 + 1] = g; - out[i * 3 + 2] = b; - } else { - out[i * 6 + 0] = out[i * 6 + 1] = r; - out[i * 6 + 2] = out[i * 6 + 3] = g; - out[i * 6 + 4] = out[i * 6 + 5] = b; - } - } else if(mode->colortype == LCT_PALETTE) { - int index = color_tree_get(tree, r, g, b, a); - if(index < 0) return 82; /*color not in palette*/ - if(mode->bitdepth == 8) out[i] = index; - else addColorBits(out, i, mode->bitdepth, (unsigned)index); - } else if(mode->colortype == LCT_GREY_ALPHA) { - unsigned char gray = r; /*((unsigned short)r + g + b) / 3u;*/ - if(mode->bitdepth == 8) { - out[i * 2 + 0] = gray; - out[i * 2 + 1] = a; - } else if(mode->bitdepth == 16) { - out[i * 4 + 0] = out[i * 4 + 1] = gray; - out[i * 4 + 2] = out[i * 4 + 3] = a; - } - } else if(mode->colortype == LCT_RGBA) { - if(mode->bitdepth == 8) { - out[i * 4 + 0] = r; - out[i * 4 + 1] = g; - out[i * 4 + 2] = b; - out[i * 4 + 3] = a; - } else { - out[i * 8 + 0] = out[i * 8 + 1] = r; - out[i * 8 + 2] = out[i * 8 + 3] = g; - out[i * 8 + 4] = out[i * 8 + 5] = b; - out[i * 8 + 6] = out[i * 8 + 7] = a; - } - } - - return 0; /*no error*/ -} - -/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/ -static void rgba16ToPixel(unsigned char* out, size_t i, - const LodePNGColorMode* mode, - unsigned short r, unsigned short g, unsigned short b, unsigned short a) { - if(mode->colortype == LCT_GREY) { - unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ - out[i * 2 + 0] = (gray >> 8) & 255; - out[i * 2 + 1] = gray & 255; - } else if(mode->colortype == LCT_RGB) { - out[i * 6 + 0] = (r >> 8) & 255; - out[i * 6 + 1] = r & 255; - out[i * 6 + 2] = (g >> 8) & 255; - out[i * 6 + 3] = g & 255; - out[i * 6 + 4] = (b >> 8) & 255; - out[i * 6 + 5] = b & 255; - } else if(mode->colortype == LCT_GREY_ALPHA) { - unsigned short gray = r; /*((unsigned)r + g + b) / 3u;*/ - out[i * 4 + 0] = (gray >> 8) & 255; - out[i * 4 + 1] = gray & 255; - out[i * 4 + 2] = (a >> 8) & 255; - out[i * 4 + 3] = a & 255; - } else if(mode->colortype == LCT_RGBA) { - out[i * 8 + 0] = (r >> 8) & 255; - out[i * 8 + 1] = r & 255; - out[i * 8 + 2] = (g >> 8) & 255; - out[i * 8 + 3] = g & 255; - out[i * 8 + 4] = (b >> 8) & 255; - out[i * 8 + 5] = b & 255; - out[i * 8 + 6] = (a >> 8) & 255; - out[i * 8 + 7] = a & 255; - } -} - -/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/ -static void getPixelColorRGBA8(unsigned char* r, unsigned char* g, - unsigned char* b, unsigned char* a, - const unsigned char* in, size_t i, - const LodePNGColorMode* mode) { - if(mode->colortype == LCT_GREY) { - if(mode->bitdepth == 8) { - *r = *g = *b = in[i]; - if(mode->key_defined && *r == mode->key_r) *a = 0; - else *a = 255; - } else if(mode->bitdepth == 16) { - *r = *g = *b = in[i * 2 + 0]; - if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; - else *a = 255; - } else { - unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ - size_t j = i * mode->bitdepth; - unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); - *r = *g = *b = (value * 255) / highest; - if(mode->key_defined && value == mode->key_r) *a = 0; - else *a = 255; - } - } else if(mode->colortype == LCT_RGB) { - if(mode->bitdepth == 8) { - *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2]; - if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0; - else *a = 255; - } else { - *r = in[i * 6 + 0]; - *g = in[i * 6 + 2]; - *b = in[i * 6 + 4]; - if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r - && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g - && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; - else *a = 255; - } - } else if(mode->colortype == LCT_PALETTE) { - unsigned index; - if(mode->bitdepth == 8) index = in[i]; - else { - size_t j = i * mode->bitdepth; - index = readBitsFromReversedStream(&j, in, mode->bitdepth); - } - /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ - *r = mode->palette[index * 4 + 0]; - *g = mode->palette[index * 4 + 1]; - *b = mode->palette[index * 4 + 2]; - *a = mode->palette[index * 4 + 3]; - } else if(mode->colortype == LCT_GREY_ALPHA) { - if(mode->bitdepth == 8) { - *r = *g = *b = in[i * 2 + 0]; - *a = in[i * 2 + 1]; - } else { - *r = *g = *b = in[i * 4 + 0]; - *a = in[i * 4 + 2]; - } - } else if(mode->colortype == LCT_RGBA) { - if(mode->bitdepth == 8) { - *r = in[i * 4 + 0]; - *g = in[i * 4 + 1]; - *b = in[i * 4 + 2]; - *a = in[i * 4 + 3]; - } else { - *r = in[i * 8 + 0]; - *g = in[i * 8 + 2]; - *b = in[i * 8 + 4]; - *a = in[i * 8 + 6]; - } - } -} - -/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color -mode test cases, optimized to convert the colors much faster, when converting -to the common case of RGBA with 8 bit per channel. buffer must be RGBA with -enough memory.*/ -static void getPixelColorsRGBA8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, - const unsigned char* LODEPNG_RESTRICT in, - const LodePNGColorMode* mode) { - unsigned num_channels = 4; - size_t i; - if(mode->colortype == LCT_GREY) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i]; - buffer[3] = 255; - } - if(mode->key_defined) { - buffer -= numpixels * num_channels; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - if(buffer[0] == mode->key_r) buffer[3] = 0; - } - } - } else if(mode->bitdepth == 16) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 2]; - buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255; - } - } else { - unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ - size_t j = 0; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); - buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; - buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255; - } - } - } else if(mode->colortype == LCT_RGB) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - lodepng_memcpy(buffer, &in[i * 3], 3); - buffer[3] = 255; - } - if(mode->key_defined) { - buffer -= numpixels * num_channels; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - if(buffer[0] == mode->key_r && buffer[1]== mode->key_g && buffer[2] == mode->key_b) buffer[3] = 0; - } - } - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = in[i * 6 + 0]; - buffer[1] = in[i * 6 + 2]; - buffer[2] = in[i * 6 + 4]; - buffer[3] = mode->key_defined - && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r - && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g - && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255; - } - } - } else if(mode->colortype == LCT_PALETTE) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned index = in[i]; - /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ - lodepng_memcpy(buffer, &mode->palette[index * 4], 4); - } - } else { - size_t j = 0; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); - /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ - lodepng_memcpy(buffer, &mode->palette[index * 4], 4); - } - } - } else if(mode->colortype == LCT_GREY_ALPHA) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; - buffer[3] = in[i * 2 + 1]; - } - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; - buffer[3] = in[i * 4 + 2]; - } - } - } else if(mode->colortype == LCT_RGBA) { - if(mode->bitdepth == 8) { - lodepng_memcpy(buffer, in, numpixels * 4); - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = in[i * 8 + 0]; - buffer[1] = in[i * 8 + 2]; - buffer[2] = in[i * 8 + 4]; - buffer[3] = in[i * 8 + 6]; - } - } - } -} - -/*Similar to getPixelColorsRGBA8, but with 3-channel RGB output.*/ -static void getPixelColorsRGB8(unsigned char* LODEPNG_RESTRICT buffer, size_t numpixels, - const unsigned char* LODEPNG_RESTRICT in, - const LodePNGColorMode* mode) { - const unsigned num_channels = 3; - size_t i; - if(mode->colortype == LCT_GREY) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i]; - } - } else if(mode->bitdepth == 16) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 2]; - } - } else { - unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/ - size_t j = 0; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth); - buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest; - } - } - } else if(mode->colortype == LCT_RGB) { - if(mode->bitdepth == 8) { - lodepng_memcpy(buffer, in, numpixels * 3); - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = in[i * 6 + 0]; - buffer[1] = in[i * 6 + 2]; - buffer[2] = in[i * 6 + 4]; - } - } - } else if(mode->colortype == LCT_PALETTE) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned index = in[i]; - /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ - lodepng_memcpy(buffer, &mode->palette[index * 4], 3); - } - } else { - size_t j = 0; - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - unsigned index = readBitsFromReversedStream(&j, in, mode->bitdepth); - /*out of bounds of palette not checked: see lodepng_color_mode_alloc_palette.*/ - lodepng_memcpy(buffer, &mode->palette[index * 4], 3); - } - } - } else if(mode->colortype == LCT_GREY_ALPHA) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0]; - } - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0]; - } - } - } else if(mode->colortype == LCT_RGBA) { - if(mode->bitdepth == 8) { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - lodepng_memcpy(buffer, &in[i * 4], 3); - } - } else { - for(i = 0; i != numpixels; ++i, buffer += num_channels) { - buffer[0] = in[i * 8 + 0]; - buffer[1] = in[i * 8 + 2]; - buffer[2] = in[i * 8 + 4]; - } - } - } -} - -/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with -given color type, but the given color type must be 16-bit itself.*/ -static void getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a, - const unsigned char* in, size_t i, const LodePNGColorMode* mode) { - if(mode->colortype == LCT_GREY) { - *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1]; - if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0; - else *a = 65535; - } else if(mode->colortype == LCT_RGB) { - *r = 256u * in[i * 6 + 0] + in[i * 6 + 1]; - *g = 256u * in[i * 6 + 2] + in[i * 6 + 3]; - *b = 256u * in[i * 6 + 4] + in[i * 6 + 5]; - if(mode->key_defined - && 256u * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r - && 256u * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g - && 256u * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0; - else *a = 65535; - } else if(mode->colortype == LCT_GREY_ALPHA) { - *r = *g = *b = 256u * in[i * 4 + 0] + in[i * 4 + 1]; - *a = 256u * in[i * 4 + 2] + in[i * 4 + 3]; - } else if(mode->colortype == LCT_RGBA) { - *r = 256u * in[i * 8 + 0] + in[i * 8 + 1]; - *g = 256u * in[i * 8 + 2] + in[i * 8 + 3]; - *b = 256u * in[i * 8 + 4] + in[i * 8 + 5]; - *a = 256u * in[i * 8 + 6] + in[i * 8 + 7]; - } -} - -unsigned lodepng_convert(unsigned char* out, const unsigned char* in, - const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, - unsigned w, unsigned h) { - size_t i; - ColorTree tree; - size_t numpixels = (size_t)w * (size_t)h; - unsigned error = 0; - - if(mode_in->colortype == LCT_PALETTE && !mode_in->palette) { - return 107; /* error: must provide palette if input mode is palette */ - } - - if(lodepng_color_mode_equal(mode_out, mode_in)) { - size_t numbytes = lodepng_get_raw_size(w, h, mode_in); - lodepng_memcpy(out, in, numbytes); - return 0; - } - - if(mode_out->colortype == LCT_PALETTE) { - size_t palettesize = mode_out->palettesize; - const unsigned char* palette = mode_out->palette; - size_t palsize = (size_t)1u << mode_out->bitdepth; - /*if the user specified output palette but did not give the values, assume - they want the values of the input color type (assuming that one is palette). - Note that we never create a new palette ourselves.*/ - if(palettesize == 0) { - palettesize = mode_in->palettesize; - palette = mode_in->palette; - /*if the input was also palette with same bitdepth, then the color types are also - equal, so copy literally. This to preserve the exact indices that were in the PNG - even in case there are duplicate colors in the palette.*/ - if(mode_in->colortype == LCT_PALETTE && mode_in->bitdepth == mode_out->bitdepth) { - size_t numbytes = lodepng_get_raw_size(w, h, mode_in); - lodepng_memcpy(out, in, numbytes); - return 0; - } - } - if(palettesize < palsize) palsize = palettesize; - color_tree_init(&tree); - for(i = 0; i != palsize; ++i) { - const unsigned char* p = &palette[i * 4]; - error = color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned)i); - if(error) break; - } - } - - if(!error) { - if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16) { - for(i = 0; i != numpixels; ++i) { - unsigned short r = 0, g = 0, b = 0, a = 0; - getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); - rgba16ToPixel(out, i, mode_out, r, g, b, a); - } - } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA) { - getPixelColorsRGBA8(out, numpixels, in, mode_in); - } else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB) { - getPixelColorsRGB8(out, numpixels, in, mode_in); - } else { - unsigned char r = 0, g = 0, b = 0, a = 0; - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); - error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a); - if(error) break; - } - } - } - - if(mode_out->colortype == LCT_PALETTE) { - color_tree_cleanup(&tree); - } - - return error; -} - - -/* Converts a single rgb color without alpha from one type to another, color bits truncated to -their bitdepth. In case of single channel (gray or palette), only the r channel is used. Slow -function, do not use to process all pixels of an image. Alpha channel not supported on purpose: -this is for bKGD, supporting alpha may prevent it from finding a color in the palette, from the -specification it looks like bKGD should ignore the alpha values of the palette since it can use -any palette index but doesn't have an alpha channel. Idem with ignoring color key. */ -unsigned lodepng_convert_rgb( - unsigned* r_out, unsigned* g_out, unsigned* b_out, - unsigned r_in, unsigned g_in, unsigned b_in, - const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in) { - unsigned r = 0, g = 0, b = 0; - unsigned mul = 65535 / ((1u << mode_in->bitdepth) - 1u); /*65535, 21845, 4369, 257, 1*/ - unsigned shift = 16 - mode_out->bitdepth; - - if(mode_in->colortype == LCT_GREY || mode_in->colortype == LCT_GREY_ALPHA) { - r = g = b = r_in * mul; - } else if(mode_in->colortype == LCT_RGB || mode_in->colortype == LCT_RGBA) { - r = r_in * mul; - g = g_in * mul; - b = b_in * mul; - } else if(mode_in->colortype == LCT_PALETTE) { - if(r_in >= mode_in->palettesize) return 82; - r = mode_in->palette[r_in * 4 + 0] * 257u; - g = mode_in->palette[r_in * 4 + 1] * 257u; - b = mode_in->palette[r_in * 4 + 2] * 257u; - } else { - return 31; - } - - /* now convert to output format */ - if(mode_out->colortype == LCT_GREY || mode_out->colortype == LCT_GREY_ALPHA) { - *r_out = r >> shift ; - } else if(mode_out->colortype == LCT_RGB || mode_out->colortype == LCT_RGBA) { - *r_out = r >> shift ; - *g_out = g >> shift ; - *b_out = b >> shift ; - } else if(mode_out->colortype == LCT_PALETTE) { - unsigned i; - /* a 16-bit color cannot be in the palette */ - if((r >> 8) != (r & 255) || (g >> 8) != (g & 255) || (b >> 8) != (b & 255)) return 82; - for(i = 0; i < mode_out->palettesize; i++) { - unsigned j = i * 4; - if((r >> 8) == mode_out->palette[j + 0] && (g >> 8) == mode_out->palette[j + 1] && - (b >> 8) == mode_out->palette[j + 2]) { - *r_out = i; - return 0; - } - } - return 82; - } else { - return 31; - } - - return 0; -} - -#ifdef LODEPNG_COMPILE_ENCODER - -void lodepng_color_stats_init(LodePNGColorStats* stats) { - /*stats*/ - stats->colored = 0; - stats->key = 0; - stats->key_r = stats->key_g = stats->key_b = 0; - stats->alpha = 0; - stats->numcolors = 0; - stats->bits = 1; - stats->numpixels = 0; - /*settings*/ - stats->allow_palette = 1; - stats->allow_greyscale = 1; -} - -/*function used for debug purposes with C++*/ -/*void printColorStats(LodePNGColorStats* p) { - std::cout << "colored: " << (int)p->colored << ", "; - std::cout << "key: " << (int)p->key << ", "; - std::cout << "key_r: " << (int)p->key_r << ", "; - std::cout << "key_g: " << (int)p->key_g << ", "; - std::cout << "key_b: " << (int)p->key_b << ", "; - std::cout << "alpha: " << (int)p->alpha << ", "; - std::cout << "numcolors: " << (int)p->numcolors << ", "; - std::cout << "bits: " << (int)p->bits << std::endl; -}*/ - -/*Returns how many bits needed to represent given value (max 8 bit)*/ -static unsigned getValueRequiredBits(unsigned char value) { - if(value == 0 || value == 255) return 1; - /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/ - if(value % 17 == 0) return value % 85 == 0 ? 2 : 4; - return 8; -} - -/*stats must already have been inited. */ -unsigned lodepng_compute_color_stats(LodePNGColorStats* stats, - const unsigned char* in, unsigned w, unsigned h, - const LodePNGColorMode* mode_in) { - size_t i; - ColorTree tree; - size_t numpixels = (size_t)w * (size_t)h; - unsigned error = 0; - - /* mark things as done already if it would be impossible to have a more expensive case */ - unsigned colored_done = lodepng_is_greyscale_type(mode_in) ? 1 : 0; - unsigned alpha_done = lodepng_can_have_alpha(mode_in) ? 0 : 1; - unsigned numcolors_done = 0; - unsigned bpp = lodepng_get_bpp(mode_in); - unsigned bits_done = (stats->bits == 1 && bpp == 1) ? 1 : 0; - unsigned sixteen = 0; /* whether the input image is 16 bit */ - unsigned maxnumcolors = 257; - if(bpp <= 8) maxnumcolors = LODEPNG_MIN(257, stats->numcolors + (1u << bpp)); - - stats->numpixels += numpixels; - - /*if palette not allowed, no need to compute numcolors*/ - if(!stats->allow_palette) numcolors_done = 1; - - color_tree_init(&tree); - - /*If the stats was already filled in from previous data, fill its palette in tree - and mark things as done already if we know they are the most expensive case already*/ - if(stats->alpha) alpha_done = 1; - if(stats->colored) colored_done = 1; - if(stats->bits == 16) numcolors_done = 1; - if(stats->bits >= bpp) bits_done = 1; - if(stats->numcolors >= maxnumcolors) numcolors_done = 1; - - if(!numcolors_done) { - for(i = 0; i < stats->numcolors; i++) { - const unsigned char* color = &stats->palette[i * 4]; - error = color_tree_add(&tree, color[0], color[1], color[2], color[3], i); - if(error) goto cleanup; - } - } - - /*Check if the 16-bit input is truly 16-bit*/ - if(mode_in->bitdepth == 16 && !sixteen) { - unsigned short r = 0, g = 0, b = 0, a = 0; - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); - if((r & 255) != ((r >> 8) & 255) || (g & 255) != ((g >> 8) & 255) || - (b & 255) != ((b >> 8) & 255) || (a & 255) != ((a >> 8) & 255)) /*first and second byte differ*/ { - stats->bits = 16; - sixteen = 1; - bits_done = 1; - numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/ - break; - } - } - } - - if(sixteen) { - unsigned short r = 0, g = 0, b = 0, a = 0; - - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); - - if(!colored_done && (r != g || r != b)) { - stats->colored = 1; - colored_done = 1; - } - - if(!alpha_done) { - unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b); - if(a != 65535 && (a != 0 || (stats->key && !matchkey))) { - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - } else if(a == 0 && !stats->alpha && !stats->key) { - stats->key = 1; - stats->key_r = r; - stats->key_g = g; - stats->key_b = b; - } else if(a == 65535 && stats->key && matchkey) { - /* Color key cannot be used if an opaque pixel also has that RGB color. */ - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - } - } - if(alpha_done && numcolors_done && colored_done && bits_done) break; - } - - if(stats->key && !stats->alpha) { - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in); - if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) { - /* Color key cannot be used if an opaque pixel also has that RGB color. */ - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - } - } - } - } else /* < 16-bit */ { - unsigned char r = 0, g = 0, b = 0, a = 0; - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); - - if(!bits_done && stats->bits < 8) { - /*only r is checked, < 8 bits is only relevant for grayscale*/ - unsigned bits = getValueRequiredBits(r); - if(bits > stats->bits) stats->bits = bits; - } - bits_done = (stats->bits >= bpp); - - if(!colored_done && (r != g || r != b)) { - stats->colored = 1; - colored_done = 1; - if(stats->bits < 8) stats->bits = 8; /*PNG has no colored modes with less than 8-bit per channel*/ - } - - if(!alpha_done) { - unsigned matchkey = (r == stats->key_r && g == stats->key_g && b == stats->key_b); - if(a != 255 && (a != 0 || (stats->key && !matchkey))) { - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ - } else if(a == 0 && !stats->alpha && !stats->key) { - stats->key = 1; - stats->key_r = r; - stats->key_g = g; - stats->key_b = b; - } else if(a == 255 && stats->key && matchkey) { - /* Color key cannot be used if an opaque pixel also has that RGB color. */ - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ - } - } - - if(!numcolors_done) { - if(!color_tree_has(&tree, r, g, b, a)) { - error = color_tree_add(&tree, r, g, b, a, stats->numcolors); - if(error) goto cleanup; - if(stats->numcolors < 256) { - unsigned char* p = stats->palette; - unsigned n = stats->numcolors; - p[n * 4 + 0] = r; - p[n * 4 + 1] = g; - p[n * 4 + 2] = b; - p[n * 4 + 3] = a; - } - ++stats->numcolors; - numcolors_done = stats->numcolors >= maxnumcolors; - } - } - - if(alpha_done && numcolors_done && colored_done && bits_done) break; - } - - if(stats->key && !stats->alpha) { - for(i = 0; i != numpixels; ++i) { - getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in); - if(a != 0 && r == stats->key_r && g == stats->key_g && b == stats->key_b) { - /* Color key cannot be used if an opaque pixel also has that RGB color. */ - stats->alpha = 1; - stats->key = 0; - alpha_done = 1; - if(stats->bits < 8) stats->bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ - } - } - } - - /*make the stats's key always 16-bit for consistency - repeat each byte twice*/ - stats->key_r += (stats->key_r << 8); - stats->key_g += (stats->key_g << 8); - stats->key_b += (stats->key_b << 8); - } - -cleanup: - color_tree_cleanup(&tree); - return error; -} - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS -/*Adds a single color to the color stats. The stats must already have been inited. The color must be given as 16-bit -(with 2 bytes repeating for 8-bit and 65535 for opaque alpha channel). This function is expensive, do not call it for -all pixels of an image but only for a few additional values. */ -static unsigned lodepng_color_stats_add(LodePNGColorStats* stats, - unsigned r, unsigned g, unsigned b, unsigned a) { - unsigned error = 0; - unsigned char image[8]; - LodePNGColorMode mode; - lodepng_color_mode_init(&mode); - image[0] = r >> 8; image[1] = r; image[2] = g >> 8; image[3] = g; - image[4] = b >> 8; image[5] = b; image[6] = a >> 8; image[7] = a; - mode.bitdepth = 16; - mode.colortype = LCT_RGBA; - error = lodepng_compute_color_stats(stats, image, 1, 1, &mode); - lodepng_color_mode_cleanup(&mode); - return error; -} -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -/*Computes a minimal PNG color model that can contain all colors as indicated by the stats. -The stats should be computed with lodepng_compute_color_stats. -mode_in is raw color profile of the image the stats were computed on, to copy palette order from when relevant. -Minimal PNG color model means the color type and bit depth that gives smallest amount of bits in the output image, -e.g. gray if only grayscale pixels, palette if less than 256 colors, color key if only single transparent color, ... -This is used if auto_convert is enabled (it is by default). -*/ -static unsigned auto_choose_color(LodePNGColorMode* mode_out, - const LodePNGColorMode* mode_in, - const LodePNGColorStats* stats) { - unsigned error = 0; - unsigned palettebits; - size_t i, n; - size_t numpixels = stats->numpixels; - unsigned palette_ok, gray_ok; - - unsigned alpha = stats->alpha; - unsigned key = stats->key; - unsigned bits = stats->bits; - - mode_out->key_defined = 0; - - if(key && numpixels <= 16) { - alpha = 1; /*too few pixels to justify tRNS chunk overhead*/ - key = 0; - if(bits < 8) bits = 8; /*PNG has no alphachannel modes with less than 8-bit per channel*/ - } - - gray_ok = !stats->colored; - if(!stats->allow_greyscale) gray_ok = 0; - if(!gray_ok && bits < 8) bits = 8; - - n = stats->numcolors; - palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8)); - palette_ok = n <= 256 && bits <= 8 && n != 0; /*n==0 means likely numcolors wasn't computed*/ - if(numpixels < n * 2) palette_ok = 0; /*don't add palette overhead if image has only a few pixels*/ - if(gray_ok && !alpha && bits <= palettebits) palette_ok = 0; /*gray is less overhead*/ - if(!stats->allow_palette) palette_ok = 0; - - if(palette_ok) { - const unsigned char* p = stats->palette; - lodepng_palette_clear(mode_out); /*remove potential earlier palette*/ - for(i = 0; i != stats->numcolors; ++i) { - error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]); - if(error) break; - } - - mode_out->colortype = LCT_PALETTE; - mode_out->bitdepth = palettebits; - - if(mode_in->colortype == LCT_PALETTE && mode_in->palettesize >= mode_out->palettesize - && mode_in->bitdepth == mode_out->bitdepth) { - /*If input should have same palette colors, keep original to preserve its order and prevent conversion*/ - lodepng_color_mode_cleanup(mode_out); - lodepng_color_mode_copy(mode_out, mode_in); - } - } else /*8-bit or 16-bit per channel*/ { - mode_out->bitdepth = bits; - mode_out->colortype = alpha ? (gray_ok ? LCT_GREY_ALPHA : LCT_RGBA) - : (gray_ok ? LCT_GREY : LCT_RGB); - if(key) { - unsigned mask = (1u << mode_out->bitdepth) - 1u; /*stats always uses 16-bit, mask converts it*/ - mode_out->key_r = stats->key_r & mask; - mode_out->key_g = stats->key_g & mask; - mode_out->key_b = stats->key_b & mask; - mode_out->key_defined = 1; - } - } - - return error; -} - -#endif /* #ifdef LODEPNG_COMPILE_ENCODER */ - -/* -Paeth predictor, used by PNG filter type 4 -The parameters are of type short, but should come from unsigned chars, the shorts -are only needed to make the paeth calculation correct. -*/ -static unsigned char paethPredictor(short a, short b, short c) { - short pa = LODEPNG_ABS(b - c); - short pb = LODEPNG_ABS(a - c); - short pc = LODEPNG_ABS(a + b - c - c); - /* return input value associated with smallest of pa, pb, pc (with certain priority if equal) */ - if(pb < pa) { a = b; pa = pb; } - return (pc < pa) ? c : a; -} - -/*shared values used by multiple Adam7 related functions*/ - -static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/ -static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/ -static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/ -static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/ - -/* -Outputs various dimensions and positions in the image related to the Adam7 reduced images. -passw: output containing the width of the 7 passes -passh: output containing the height of the 7 passes -filter_passstart: output containing the index of the start and end of each - reduced image with filter bytes -padded_passstart output containing the index of the start and end of each - reduced image when without filter bytes but with padded scanlines -passstart: output containing the index of the start and end of each reduced - image without padding between scanlines, but still padding between the images -w, h: width and height of non-interlaced image -bpp: bits per pixel -"padded" is only relevant if bpp is less than 8 and a scanline or image does not - end at a full byte -*/ -static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8], - size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp) { - /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/ - unsigned i; - - /*calculate width and height in pixels of each pass*/ - for(i = 0; i != 7; ++i) { - passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i]; - passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i]; - if(passw[i] == 0) passh[i] = 0; - if(passh[i] == 0) passw[i] = 0; - } - - filter_passstart[0] = padded_passstart[0] = passstart[0] = 0; - for(i = 0; i != 7; ++i) { - /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/ - filter_passstart[i + 1] = filter_passstart[i] - + ((passw[i] && passh[i]) ? passh[i] * (1u + (passw[i] * bpp + 7u) / 8u) : 0); - /*bits padded if needed to fill full byte at end of each scanline*/ - padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7u) / 8u); - /*only padded at end of reduced image*/ - passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7u) / 8u; - } -} - -#ifdef LODEPNG_COMPILE_DECODER - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / PNG Decoder / */ -/* ////////////////////////////////////////////////////////////////////////// */ - -/*read the information from the header and store it in the LodePNGInfo. return value is error*/ -unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state, - const unsigned char* in, size_t insize) { - unsigned width, height; - LodePNGInfo* info = &state->info_png; - if(insize == 0 || in == 0) { - CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/ - } - if(insize < 33) { - CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/ - } - - /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/ - /* TODO: remove this. One should use a new LodePNGState for new sessions */ - lodepng_info_cleanup(info); - lodepng_info_init(info); - - if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 - || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { - CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/ - } - if(lodepng_chunk_length(in + 8) != 13) { - CERROR_RETURN_ERROR(state->error, 94); /*error: header size must be 13 bytes*/ - } - if(!lodepng_chunk_type_equals(in + 8, "IHDR")) { - CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/ - } - - /*read the values given in the header*/ - width = lodepng_read32bitInt(&in[16]); - height = lodepng_read32bitInt(&in[20]); - /*TODO: remove the undocumented feature that allows to give null pointers to width or height*/ - if(w) *w = width; - if(h) *h = height; - info->color.bitdepth = in[24]; - info->color.colortype = (LodePNGColorType)in[25]; - info->compression_method = in[26]; - info->filter_method = in[27]; - info->interlace_method = in[28]; - - /*errors returned only after the parsing so other values are still output*/ - - /*error: invalid image size*/ - if(width == 0 || height == 0) CERROR_RETURN_ERROR(state->error, 93); - /*error: invalid colortype or bitdepth combination*/ - state->error = checkColorValidity(info->color.colortype, info->color.bitdepth); - if(state->error) return state->error; - /*error: only compression method 0 is allowed in the specification*/ - if(info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32); - /*error: only filter method 0 is allowed in the specification*/ - if(info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33); - /*error: only interlace methods 0 and 1 exist in the specification*/ - if(info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34); - - if(!state->decoder.ignore_crc) { - unsigned CRC = lodepng_read32bitInt(&in[29]); - unsigned checksum = lodepng_crc32(&in[12], 17); - if(CRC != checksum) { - CERROR_RETURN_ERROR(state->error, 57); /*invalid CRC*/ - } - } - - return state->error; -} - -static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon, - size_t bytewidth, unsigned char filterType, size_t length) { - /* - For PNG filter method 0 - unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte, - the filter works byte per byte (bytewidth = 1) - precon is the previous unfiltered scanline, recon the result, scanline the current one - the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead - recon and scanline MAY be the same memory address! precon must be disjoint. - */ - - size_t i; - switch(filterType) { - case 0: - for(i = 0; i != length; ++i) recon[i] = scanline[i]; - break; - case 1: { - size_t j = 0; - for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; - for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + recon[j]; - break; - } - case 2: - if(precon) { - for(i = 0; i != length; ++i) recon[i] = scanline[i] + precon[i]; - } else { - for(i = 0; i != length; ++i) recon[i] = scanline[i]; - } - break; - case 3: - if(precon) { - size_t j = 0; - for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i] + (precon[i] >> 1u); - /* Unroll independent paths of this predictor. A 6x and 8x version is also possible but that adds - too much code. Whether this speeds up anything depends on compiler and settings. */ - if(bytewidth >= 4) { - for(; i + 3 < length; i += 4, j += 4) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3]; - recon[i + 0] = s0 + ((r0 + p0) >> 1u); - recon[i + 1] = s1 + ((r1 + p1) >> 1u); - recon[i + 2] = s2 + ((r2 + p2) >> 1u); - recon[i + 3] = s3 + ((r3 + p3) >> 1u); - } - } else if(bytewidth >= 3) { - for(; i + 2 < length; i += 3, j += 3) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2]; - recon[i + 0] = s0 + ((r0 + p0) >> 1u); - recon[i + 1] = s1 + ((r1 + p1) >> 1u); - recon[i + 2] = s2 + ((r2 + p2) >> 1u); - } - } else if(bytewidth >= 2) { - for(; i + 1 < length; i += 2, j += 2) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1]; - recon[i + 0] = s0 + ((r0 + p0) >> 1u); - recon[i + 1] = s1 + ((r1 + p1) >> 1u); - } - } - for(; i != length; ++i, ++j) recon[i] = scanline[i] + ((recon[j] + precon[i]) >> 1u); - } else { - size_t j = 0; - for(i = 0; i != bytewidth; ++i) recon[i] = scanline[i]; - for(i = bytewidth; i != length; ++i, ++j) recon[i] = scanline[i] + (recon[j] >> 1u); - } - break; - case 4: - if(precon) { - size_t j = 0; - for(i = 0; i != bytewidth; ++i) { - recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/ - } - - /* Unroll independent paths of the paeth predictor. A 6x and 8x version is also possible but that - adds too much code. Whether this speeds up anything depends on compiler and settings. */ - if(bytewidth >= 4) { - for(; i + 3 < length; i += 4, j += 4) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2], s3 = scanline[i + 3]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2], r3 = recon[j + 3]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2], p3 = precon[i + 3]; - unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2], q3 = precon[j + 3]; - recon[i + 0] = s0 + paethPredictor(r0, p0, q0); - recon[i + 1] = s1 + paethPredictor(r1, p1, q1); - recon[i + 2] = s2 + paethPredictor(r2, p2, q2); - recon[i + 3] = s3 + paethPredictor(r3, p3, q3); - } - } else if(bytewidth >= 3) { - for(; i + 2 < length; i += 3, j += 3) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1], s2 = scanline[i + 2]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1], r2 = recon[j + 2]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1], p2 = precon[i + 2]; - unsigned char q0 = precon[j + 0], q1 = precon[j + 1], q2 = precon[j + 2]; - recon[i + 0] = s0 + paethPredictor(r0, p0, q0); - recon[i + 1] = s1 + paethPredictor(r1, p1, q1); - recon[i + 2] = s2 + paethPredictor(r2, p2, q2); - } - } else if(bytewidth >= 2) { - for(; i + 1 < length; i += 2, j += 2) { - unsigned char s0 = scanline[i + 0], s1 = scanline[i + 1]; - unsigned char r0 = recon[j + 0], r1 = recon[j + 1]; - unsigned char p0 = precon[i + 0], p1 = precon[i + 1]; - unsigned char q0 = precon[j + 0], q1 = precon[j + 1]; - recon[i + 0] = s0 + paethPredictor(r0, p0, q0); - recon[i + 1] = s1 + paethPredictor(r1, p1, q1); - } - } - - for(; i != length; ++i, ++j) { - recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[j])); - } - } else { - size_t j = 0; - for(i = 0; i != bytewidth; ++i) { - recon[i] = scanline[i]; - } - for(i = bytewidth; i != length; ++i, ++j) { - /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/ - recon[i] = (scanline[i] + recon[j]); - } - } - break; - default: return 36; /*error: invalid filter type given*/ - } - return 0; -} - -static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { - /* - For PNG filter method 0 - this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times) - out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline - w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel - in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes) - */ - - unsigned y; - unsigned char* prevline = 0; - - /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ - size_t bytewidth = (bpp + 7u) / 8u; - /*the width of a scanline in bytes, not including the filter type*/ - size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u; - - for(y = 0; y < h; ++y) { - size_t outindex = linebytes * y; - size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ - unsigned char filterType = in[inindex]; - - CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes)); - - prevline = &out[outindex]; - } - - return 0; -} - -/* -in: Adam7 interlaced image, with no padding bits between scanlines, but between - reduced images so that each reduced image starts at a byte. -out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h -bpp: bits per pixel -out has the following size in bits: w * h * bpp. -in is possibly bigger due to padding bits between reduced images. -out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation -(because that's likely a little bit faster) -NOTE: comments about padding bits are only relevant if bpp < 8 -*/ -static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { - unsigned passw[7], passh[7]; - size_t filter_passstart[8], padded_passstart[8], passstart[8]; - unsigned i; - - Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); - - if(bpp >= 8) { - for(i = 0; i != 7; ++i) { - unsigned x, y, b; - size_t bytewidth = bpp / 8u; - for(y = 0; y < passh[i]; ++y) - for(x = 0; x < passw[i]; ++x) { - size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth; - size_t pixeloutstart = ((ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * (size_t)w - + ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bytewidth; - for(b = 0; b < bytewidth; ++b) { - out[pixeloutstart + b] = in[pixelinstart + b]; - } - } - } - } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ { - for(i = 0; i != 7; ++i) { - unsigned x, y, b; - unsigned ilinebits = bpp * passw[i]; - unsigned olinebits = bpp * w; - size_t obp, ibp; /*bit pointers (for out and in buffer)*/ - for(y = 0; y < passh[i]; ++y) - for(x = 0; x < passw[i]; ++x) { - ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp); - obp = (ADAM7_IY[i] + (size_t)y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + (size_t)x * ADAM7_DX[i]) * bpp; - for(b = 0; b < bpp; ++b) { - unsigned char bit = readBitFromReversedStream(&ibp, in); - setBitOfReversedStream(&obp, out, bit); - } - } - } - } -} - -static void removePaddingBits(unsigned char* out, const unsigned char* in, - size_t olinebits, size_t ilinebits, unsigned h) { - /* - After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need - to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers - for the Adam7 code, the color convert code and the output to the user. - in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must - have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits - also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7 - only useful if (ilinebits - olinebits) is a value in the range 1..7 - */ - unsigned y; - size_t diff = ilinebits - olinebits; - size_t ibp = 0, obp = 0; /*input and output bit pointers*/ - for(y = 0; y < h; ++y) { - size_t x; - for(x = 0; x < olinebits; ++x) { - unsigned char bit = readBitFromReversedStream(&ibp, in); - setBitOfReversedStream(&obp, out, bit); - } - ibp += diff; - } -} - -/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from -the IDAT chunks (with filter index bytes and possible padding bits) -return value is error*/ -static unsigned postProcessScanlines(unsigned char* out, unsigned char* in, - unsigned w, unsigned h, const LodePNGInfo* info_png) { - /* - This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype. - Steps: - *) if no Adam7: 1) unfilter 2) remove padding bits (= possible extra bits per scanline if bpp < 8) - *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace - NOTE: the in buffer will be overwritten with intermediate data! - */ - unsigned bpp = lodepng_get_bpp(&info_png->color); - if(bpp == 0) return 31; /*error: invalid colortype*/ - - if(info_png->interlace_method == 0) { - if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) { - CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp)); - removePaddingBits(out, in, w * bpp, ((w * bpp + 7u) / 8u) * 8u, h); - } - /*we can immediately filter into the out buffer, no other steps needed*/ - else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp)); - } else /*interlace_method is 1 (Adam7)*/ { - unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8]; - unsigned i; - - Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); - - for(i = 0; i != 7; ++i) { - CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp)); - /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline, - move bytes instead of bits or move not at all*/ - if(bpp < 8) { - /*remove padding bits in scanlines; after this there still may be padding - bits between the different reduced images: each reduced image still starts nicely at a byte*/ - removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp, - ((passw[i] * bpp + 7u) / 8u) * 8u, passh[i]); - } - } - - Adam7_deinterlace(out, in, w, h, bpp); - } - - return 0; -} - -static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { - unsigned pos = 0, i; - color->palettesize = chunkLength / 3u; - if(color->palettesize == 0 || color->palettesize > 256) return 38; /*error: palette too small or big*/ - lodepng_color_mode_alloc_palette(color); - if(!color->palette && color->palettesize) { - color->palettesize = 0; - return 83; /*alloc fail*/ - } - - for(i = 0; i != color->palettesize; ++i) { - color->palette[4 * i + 0] = data[pos++]; /*R*/ - color->palette[4 * i + 1] = data[pos++]; /*G*/ - color->palette[4 * i + 2] = data[pos++]; /*B*/ - color->palette[4 * i + 3] = 255; /*alpha*/ - } - - return 0; /* OK */ -} - -static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength) { - unsigned i; - if(color->colortype == LCT_PALETTE) { - /*error: more alpha values given than there are palette entries*/ - if(chunkLength > color->palettesize) return 39; - - for(i = 0; i != chunkLength; ++i) color->palette[4 * i + 3] = data[i]; - } else if(color->colortype == LCT_GREY) { - /*error: this chunk must be 2 bytes for grayscale image*/ - if(chunkLength != 2) return 30; - - color->key_defined = 1; - color->key_r = color->key_g = color->key_b = 256u * data[0] + data[1]; - } else if(color->colortype == LCT_RGB) { - /*error: this chunk must be 6 bytes for RGB image*/ - if(chunkLength != 6) return 41; - - color->key_defined = 1; - color->key_r = 256u * data[0] + data[1]; - color->key_g = 256u * data[2] + data[3]; - color->key_b = 256u * data[4] + data[5]; - } - else return 42; /*error: tRNS chunk not allowed for other color models*/ - - return 0; /* OK */ -} - - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS -/*background color chunk (bKGD)*/ -static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(info->color.colortype == LCT_PALETTE) { - /*error: this chunk must be 1 byte for indexed color image*/ - if(chunkLength != 1) return 43; - - /*error: invalid palette index, or maybe this chunk appeared before PLTE*/ - if(data[0] >= info->color.palettesize) return 103; - - info->background_defined = 1; - info->background_r = info->background_g = info->background_b = data[0]; - } else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) { - /*error: this chunk must be 2 bytes for grayscale image*/ - if(chunkLength != 2) return 44; - - /*the values are truncated to bitdepth in the PNG file*/ - info->background_defined = 1; - info->background_r = info->background_g = info->background_b = 256u * data[0] + data[1]; - } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { - /*error: this chunk must be 6 bytes for grayscale image*/ - if(chunkLength != 6) return 45; - - /*the values are truncated to bitdepth in the PNG file*/ - info->background_defined = 1; - info->background_r = 256u * data[0] + data[1]; - info->background_g = 256u * data[2] + data[3]; - info->background_b = 256u * data[4] + data[5]; - } - - return 0; /* OK */ -} - -/*text chunk (tEXt)*/ -static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - unsigned error = 0; - char *key = 0, *str = 0; - - while(!error) /*not really a while loop, only used to break on error*/ { - unsigned length, string2_begin; - - length = 0; - while(length < chunkLength && data[length] != 0) ++length; - /*even though it's not allowed by the standard, no error is thrown if - there's no null termination char, if the text is empty*/ - if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ - - key = (char*)lodepng_malloc(length + 1); - if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(key, data, length); - key[length] = 0; - - string2_begin = length + 1; /*skip keyword null terminator*/ - - length = (unsigned)(chunkLength < string2_begin ? 0 : chunkLength - string2_begin); - str = (char*)lodepng_malloc(length + 1); - if(!str) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(str, data + string2_begin, length); - str[length] = 0; - - error = lodepng_add_text(info, key, str); - - break; - } - - lodepng_free(key); - lodepng_free(str); - - return error; -} - -/*compressed text chunk (zTXt)*/ -static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, - const unsigned char* data, size_t chunkLength) { - unsigned error = 0; - - /*copy the object to change parameters in it*/ - LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; - - unsigned length, string2_begin; - char *key = 0; - unsigned char* str = 0; - size_t size = 0; - - while(!error) /*not really a while loop, only used to break on error*/ { - for(length = 0; length < chunkLength && data[length] != 0; ++length) ; - if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ - if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ - - key = (char*)lodepng_malloc(length + 1); - if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(key, data, length); - key[length] = 0; - - if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ - - string2_begin = length + 2; - if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/ - - length = (unsigned)chunkLength - string2_begin; - zlibsettings.max_output_size = decoder->max_text_size; - /*will fail if zlib error, e.g. if length is too small*/ - error = zlib_decompress(&str, &size, 0, &data[string2_begin], - length, &zlibsettings); - /*error: compressed text larger than decoder->max_text_size*/ - if(error && size > zlibsettings.max_output_size) error = 112; - if(error) break; - error = lodepng_add_text_sized(info, key, (char*)str, size); - break; - } - - lodepng_free(key); - lodepng_free(str); - - return error; -} - -/*international text chunk (iTXt)*/ -static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, - const unsigned char* data, size_t chunkLength) { - unsigned error = 0; - unsigned i; - - /*copy the object to change parameters in it*/ - LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; - - unsigned length, begin, compressed; - char *key = 0, *langtag = 0, *transkey = 0; - - while(!error) /*not really a while loop, only used to break on error*/ { - /*Quick check if the chunk length isn't too small. Even without check - it'd still fail with other error checks below if it's too short. This just gives a different error code.*/ - if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/ - - /*read the key*/ - for(length = 0; length < chunkLength && data[length] != 0; ++length) ; - if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/ - if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/ - - key = (char*)lodepng_malloc(length + 1); - if(!key) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(key, data, length); - key[length] = 0; - - /*read the compression method*/ - compressed = data[length + 1]; - if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/ - - /*even though it's not allowed by the standard, no error is thrown if - there's no null termination char, if the text is empty for the next 3 texts*/ - - /*read the langtag*/ - begin = length + 3; - length = 0; - for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; - - langtag = (char*)lodepng_malloc(length + 1); - if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(langtag, data + begin, length); - langtag[length] = 0; - - /*read the transkey*/ - begin += length + 1; - length = 0; - for(i = begin; i < chunkLength && data[i] != 0; ++i) ++length; - - transkey = (char*)lodepng_malloc(length + 1); - if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/ - - lodepng_memcpy(transkey, data + begin, length); - transkey[length] = 0; - - /*read the actual text*/ - begin += length + 1; - - length = (unsigned)chunkLength < begin ? 0 : (unsigned)chunkLength - begin; - - if(compressed) { - unsigned char* str = 0; - size_t size = 0; - zlibsettings.max_output_size = decoder->max_text_size; - /*will fail if zlib error, e.g. if length is too small*/ - error = zlib_decompress(&str, &size, 0, &data[begin], - length, &zlibsettings); - /*error: compressed text larger than decoder->max_text_size*/ - if(error && size > zlibsettings.max_output_size) error = 112; - if(!error) error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)str, size); - lodepng_free(str); - } else { - error = lodepng_add_itext_sized(info, key, langtag, transkey, (char*)(data + begin), length); - } - - break; - } - - lodepng_free(key); - lodepng_free(langtag); - lodepng_free(transkey); - - return error; -} - -static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(chunkLength != 7) return 73; /*invalid tIME chunk size*/ - - info->time_defined = 1; - info->time.year = 256u * data[0] + data[1]; - info->time.month = data[2]; - info->time.day = data[3]; - info->time.hour = data[4]; - info->time.minute = data[5]; - info->time.second = data[6]; - - return 0; /* OK */ -} - -static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/ - - info->phys_defined = 1; - info->phys_x = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; - info->phys_y = 16777216u * data[4] + 65536u * data[5] + 256u * data[6] + data[7]; - info->phys_unit = data[8]; - - return 0; /* OK */ -} - -static unsigned readChunk_gAMA(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(chunkLength != 4) return 96; /*invalid gAMA chunk size*/ - - info->gama_defined = 1; - info->gama_gamma = 16777216u * data[0] + 65536u * data[1] + 256u * data[2] + data[3]; - - return 0; /* OK */ -} - -static unsigned readChunk_cHRM(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(chunkLength != 32) return 97; /*invalid cHRM chunk size*/ - - info->chrm_defined = 1; - info->chrm_white_x = 16777216u * data[ 0] + 65536u * data[ 1] + 256u * data[ 2] + data[ 3]; - info->chrm_white_y = 16777216u * data[ 4] + 65536u * data[ 5] + 256u * data[ 6] + data[ 7]; - info->chrm_red_x = 16777216u * data[ 8] + 65536u * data[ 9] + 256u * data[10] + data[11]; - info->chrm_red_y = 16777216u * data[12] + 65536u * data[13] + 256u * data[14] + data[15]; - info->chrm_green_x = 16777216u * data[16] + 65536u * data[17] + 256u * data[18] + data[19]; - info->chrm_green_y = 16777216u * data[20] + 65536u * data[21] + 256u * data[22] + data[23]; - info->chrm_blue_x = 16777216u * data[24] + 65536u * data[25] + 256u * data[26] + data[27]; - info->chrm_blue_y = 16777216u * data[28] + 65536u * data[29] + 256u * data[30] + data[31]; - - return 0; /* OK */ -} - -static unsigned readChunk_sRGB(LodePNGInfo* info, const unsigned char* data, size_t chunkLength) { - if(chunkLength != 1) return 98; /*invalid sRGB chunk size (this one is never ignored)*/ - - info->srgb_defined = 1; - info->srgb_intent = data[0]; - - return 0; /* OK */ -} - -static unsigned readChunk_iCCP(LodePNGInfo* info, const LodePNGDecoderSettings* decoder, - const unsigned char* data, size_t chunkLength) { - unsigned error = 0; - unsigned i; - size_t size = 0; - /*copy the object to change parameters in it*/ - LodePNGDecompressSettings zlibsettings = decoder->zlibsettings; - - unsigned length, string2_begin; - - info->iccp_defined = 1; - if(info->iccp_name) lodepng_clear_icc(info); - - for(length = 0; length < chunkLength && data[length] != 0; ++length) ; - if(length + 2 >= chunkLength) return 75; /*no null termination, corrupt?*/ - if(length < 1 || length > 79) return 89; /*keyword too short or long*/ - - info->iccp_name = (char*)lodepng_malloc(length + 1); - if(!info->iccp_name) return 83; /*alloc fail*/ - - info->iccp_name[length] = 0; - for(i = 0; i != length; ++i) info->iccp_name[i] = (char)data[i]; - - if(data[length + 1] != 0) return 72; /*the 0 byte indicating compression must be 0*/ - - string2_begin = length + 2; - if(string2_begin > chunkLength) return 75; /*no null termination, corrupt?*/ - - length = (unsigned)chunkLength - string2_begin; - zlibsettings.max_output_size = decoder->max_icc_size; - error = zlib_decompress(&info->iccp_profile, &size, 0, - &data[string2_begin], - length, &zlibsettings); - /*error: ICC profile larger than decoder->max_icc_size*/ - if(error && size > zlibsettings.max_output_size) error = 113; - info->iccp_profile_size = size; - if(!error && !info->iccp_profile_size) error = 100; /*invalid ICC profile size*/ - return error; -} -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos, - const unsigned char* in, size_t insize) { - const unsigned char* chunk = in + pos; - unsigned chunkLength; - const unsigned char* data; - unsigned unhandled = 0; - unsigned error = 0; - - if(pos + 4 > insize) return 30; - chunkLength = lodepng_chunk_length(chunk); - if(chunkLength > 2147483647) return 63; - data = lodepng_chunk_data_const(chunk); - if(data + chunkLength + 4 > in + insize) return 30; - - if(lodepng_chunk_type_equals(chunk, "PLTE")) { - error = readChunk_PLTE(&state->info_png.color, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { - error = readChunk_tRNS(&state->info_png.color, data, chunkLength); -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { - error = readChunk_bKGD(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { - error = readChunk_tEXt(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { - error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { - error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "tIME")) { - error = readChunk_tIME(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { - error = readChunk_pHYs(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { - error = readChunk_gAMA(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { - error = readChunk_cHRM(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { - error = readChunk_sRGB(&state->info_png, data, chunkLength); - } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { - error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength); -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - } else { - /* unhandled chunk is ok (is not an error) */ - unhandled = 1; - } - - if(!error && !unhandled && !state->decoder.ignore_crc) { - if(lodepng_chunk_check_crc(chunk)) return 57; /*invalid CRC*/ - } - - return error; -} - -/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/ -static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h, - LodePNGState* state, - const unsigned char* in, size_t insize) { - unsigned char IEND = 0; - const unsigned char* chunk; - unsigned char* idat; /*the data from idat chunks, zlib compressed*/ - size_t idatsize = 0; - unsigned char* scanlines = 0; - size_t scanlines_size = 0, expected_size = 0; - size_t outsize = 0; - - /*for unknown chunk order*/ - unsigned unknown = 0; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/ -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - - - /* safe output values in case error happens */ - *out = 0; - *w = *h = 0; - - state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/ - if(state->error) return; - - if(lodepng_pixel_overflow(*w, *h, &state->info_png.color, &state->info_raw)) { - CERROR_RETURN(state->error, 92); /*overflow possible due to amount of pixels*/ - } - - /*the input filesize is a safe upper bound for the sum of idat chunks size*/ - idat = (unsigned char*)lodepng_malloc(insize); - if(!idat) CERROR_RETURN(state->error, 83); /*alloc fail*/ - - chunk = &in[33]; /*first byte of the first chunk after the header*/ - - /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. - IDAT data is put at the start of the in buffer*/ - while(!IEND && !state->error) { - unsigned chunkLength; - const unsigned char* data; /*the data in the chunk*/ - - /*error: size of the in buffer too small to contain next chunk*/ - if((size_t)((chunk - in) + 12) > insize || chunk < in) { - if(state->decoder.ignore_end) break; /*other errors may still happen though*/ - CERROR_BREAK(state->error, 30); - } - - /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/ - chunkLength = lodepng_chunk_length(chunk); - /*error: chunk length larger than the max PNG chunk size*/ - if(chunkLength > 2147483647) { - if(state->decoder.ignore_end) break; /*other errors may still happen though*/ - CERROR_BREAK(state->error, 63); - } - - if((size_t)((chunk - in) + chunkLength + 12) > insize || (chunk + chunkLength + 12) < in) { - CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk*/ - } - - data = lodepng_chunk_data_const(chunk); - - unknown = 0; - - /*IDAT chunk, containing compressed image data*/ - if(lodepng_chunk_type_equals(chunk, "IDAT")) { - size_t newsize; - if(lodepng_addofl(idatsize, chunkLength, &newsize)) CERROR_BREAK(state->error, 95); - if(newsize > insize) CERROR_BREAK(state->error, 95); - lodepng_memcpy(idat + idatsize, data, chunkLength); - idatsize += chunkLength; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - critical_pos = 3; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - } else if(lodepng_chunk_type_equals(chunk, "IEND")) { - /*IEND chunk*/ - IEND = 1; - } else if(lodepng_chunk_type_equals(chunk, "PLTE")) { - /*palette chunk (PLTE)*/ - state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength); - if(state->error) break; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - critical_pos = 2; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - } else if(lodepng_chunk_type_equals(chunk, "tRNS")) { - /*palette transparency chunk (tRNS). Even though this one is an ancillary chunk , it is still compiled - in without 'LODEPNG_COMPILE_ANCILLARY_CHUNKS' because it contains essential color information that - affects the alpha channel of pixels. */ - state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength); - if(state->error) break; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*background color chunk (bKGD)*/ - } else if(lodepng_chunk_type_equals(chunk, "bKGD")) { - state->error = readChunk_bKGD(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "tEXt")) { - /*text chunk (tEXt)*/ - if(state->decoder.read_text_chunks) { - state->error = readChunk_tEXt(&state->info_png, data, chunkLength); - if(state->error) break; - } - } else if(lodepng_chunk_type_equals(chunk, "zTXt")) { - /*compressed text chunk (zTXt)*/ - if(state->decoder.read_text_chunks) { - state->error = readChunk_zTXt(&state->info_png, &state->decoder, data, chunkLength); - if(state->error) break; - } - } else if(lodepng_chunk_type_equals(chunk, "iTXt")) { - /*international text chunk (iTXt)*/ - if(state->decoder.read_text_chunks) { - state->error = readChunk_iTXt(&state->info_png, &state->decoder, data, chunkLength); - if(state->error) break; - } - } else if(lodepng_chunk_type_equals(chunk, "tIME")) { - state->error = readChunk_tIME(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "pHYs")) { - state->error = readChunk_pHYs(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "gAMA")) { - state->error = readChunk_gAMA(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "cHRM")) { - state->error = readChunk_cHRM(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "sRGB")) { - state->error = readChunk_sRGB(&state->info_png, data, chunkLength); - if(state->error) break; - } else if(lodepng_chunk_type_equals(chunk, "iCCP")) { - state->error = readChunk_iCCP(&state->info_png, &state->decoder, data, chunkLength); - if(state->error) break; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - } else /*it's not an implemented chunk type, so ignore it: skip over the data*/ { - /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/ - if(!state->decoder.ignore_critical && !lodepng_chunk_ancillary(chunk)) { - CERROR_BREAK(state->error, 69); - } - - unknown = 1; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - if(state->decoder.remember_unknown_chunks) { - state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1], - &state->info_png.unknown_chunks_size[critical_pos - 1], chunk); - if(state->error) break; - } -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - } - - if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/ { - if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/ - } - - if(!IEND) chunk = lodepng_chunk_next_const(chunk, in + insize); - } - - if(!state->error && state->info_png.color.colortype == LCT_PALETTE && !state->info_png.color.palette) { - state->error = 106; /* error: PNG file must have PLTE chunk if color type is palette */ - } - - if(!state->error) { - /*predict output size, to allocate exact size for output buffer to avoid more dynamic allocation. - If the decompressed size does not match the prediction, the image must be corrupt.*/ - if(state->info_png.interlace_method == 0) { - size_t bpp = lodepng_get_bpp(&state->info_png.color); - expected_size = lodepng_get_raw_size_idat(*w, *h, bpp); - } else { - size_t bpp = lodepng_get_bpp(&state->info_png.color); - /*Adam-7 interlaced: expected size is the sum of the 7 sub-images sizes*/ - expected_size = 0; - expected_size += lodepng_get_raw_size_idat((*w + 7) >> 3, (*h + 7) >> 3, bpp); - if(*w > 4) expected_size += lodepng_get_raw_size_idat((*w + 3) >> 3, (*h + 7) >> 3, bpp); - expected_size += lodepng_get_raw_size_idat((*w + 3) >> 2, (*h + 3) >> 3, bpp); - if(*w > 2) expected_size += lodepng_get_raw_size_idat((*w + 1) >> 2, (*h + 3) >> 2, bpp); - expected_size += lodepng_get_raw_size_idat((*w + 1) >> 1, (*h + 1) >> 2, bpp); - if(*w > 1) expected_size += lodepng_get_raw_size_idat((*w + 0) >> 1, (*h + 1) >> 1, bpp); - expected_size += lodepng_get_raw_size_idat((*w + 0), (*h + 0) >> 1, bpp); - } - - state->error = zlib_decompress(&scanlines, &scanlines_size, expected_size, idat, idatsize, &state->decoder.zlibsettings); - } - if(!state->error && scanlines_size != expected_size) state->error = 91; /*decompressed size doesn't match prediction*/ - lodepng_free(idat); - - if(!state->error) { - outsize = lodepng_get_raw_size(*w, *h, &state->info_png.color); - *out = (unsigned char*)lodepng_malloc(outsize); - if(!*out) state->error = 83; /*alloc fail*/ - } - if(!state->error) { - lodepng_memset(*out, 0, outsize); - state->error = postProcessScanlines(*out, scanlines, *w, *h, &state->info_png); - } - lodepng_free(scanlines); -} - -unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, - LodePNGState* state, - const unsigned char* in, size_t insize) { - *out = 0; - decodeGeneric(out, w, h, state, in, insize); - if(state->error) return state->error; - if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color)) { - /*same color type, no copying or converting of data needed*/ - /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype - the raw image has to the end user*/ - if(!state->decoder.color_convert) { - state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color); - if(state->error) return state->error; - } - } else { /*color conversion needed*/ - unsigned char* data = *out; - size_t outsize; - - /*TODO: check if this works according to the statement in the documentation: "The converter can convert - from grayscale input color type, to 8-bit grayscale or grayscale with alpha"*/ - if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA) - && !(state->info_raw.bitdepth == 8)) { - return 56; /*unsupported color mode conversion*/ - } - - outsize = lodepng_get_raw_size(*w, *h, &state->info_raw); - *out = (unsigned char*)lodepng_malloc(outsize); - if(!(*out)) { - state->error = 83; /*alloc fail*/ - } - else state->error = lodepng_convert(*out, data, &state->info_raw, - &state->info_png.color, *w, *h); - lodepng_free(data); - } - return state->error; -} - -unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, - size_t insize, LodePNGColorType colortype, unsigned bitdepth) { - unsigned error; - LodePNGState state; - lodepng_state_init(&state); - state.info_raw.colortype = colortype; - state.info_raw.bitdepth = bitdepth; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*disable reading things that this function doesn't output*/ - state.decoder.read_text_chunks = 0; - state.decoder.remember_unknown_chunks = 0; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - error = lodepng_decode(out, w, h, &state, in, insize); - lodepng_state_cleanup(&state); - return error; -} - -unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { - return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8); -} - -unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize) { - return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8); -} - -#ifdef LODEPNG_COMPILE_DISK -unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename, - LodePNGColorType colortype, unsigned bitdepth) { - unsigned char* buffer = 0; - size_t buffersize; - unsigned error; - /* safe output values in case error happens */ - *out = 0; - *w = *h = 0; - error = lodepng_load_file(&buffer, &buffersize, filename); - if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth); - lodepng_free(buffer); - return error; -} - -unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { - return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8); -} - -unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename) { - return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8); -} -#endif /*LODEPNG_COMPILE_DISK*/ - -void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings) { - settings->color_convert = 1; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - settings->read_text_chunks = 1; - settings->remember_unknown_chunks = 0; - settings->max_text_size = 16777216; - settings->max_icc_size = 16777216; /* 16MB is much more than enough for any reasonable ICC profile */ -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - settings->ignore_crc = 0; - settings->ignore_critical = 0; - settings->ignore_end = 0; - lodepng_decompress_settings_init(&settings->zlibsettings); -} - -#endif /*LODEPNG_COMPILE_DECODER*/ - -#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) - -void lodepng_state_init(LodePNGState* state) { -#ifdef LODEPNG_COMPILE_DECODER - lodepng_decoder_settings_init(&state->decoder); -#endif /*LODEPNG_COMPILE_DECODER*/ -#ifdef LODEPNG_COMPILE_ENCODER - lodepng_encoder_settings_init(&state->encoder); -#endif /*LODEPNG_COMPILE_ENCODER*/ - lodepng_color_mode_init(&state->info_raw); - lodepng_info_init(&state->info_png); - state->error = 1; -} - -void lodepng_state_cleanup(LodePNGState* state) { - lodepng_color_mode_cleanup(&state->info_raw); - lodepng_info_cleanup(&state->info_png); -} - -void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source) { - lodepng_state_cleanup(dest); - *dest = *source; - lodepng_color_mode_init(&dest->info_raw); - lodepng_info_init(&dest->info_png); - dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return; - dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); if(dest->error) return; -} - -#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */ - -#ifdef LODEPNG_COMPILE_ENCODER - -/* ////////////////////////////////////////////////////////////////////////// */ -/* / PNG Encoder / */ -/* ////////////////////////////////////////////////////////////////////////// */ - - -static unsigned writeSignature(ucvector* out) { - size_t pos = out->size; - const unsigned char signature[] = {137, 80, 78, 71, 13, 10, 26, 10}; - /*8 bytes PNG signature, aka the magic bytes*/ - if(!ucvector_resize(out, out->size + 8)) return 83; /*alloc fail*/ - lodepng_memcpy(out->data + pos, signature, 8); - return 0; -} - -static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method) { - unsigned char *chunk, *data; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 13, "IHDR")); - data = chunk + 8; - - lodepng_set32bitInt(data + 0, w); /*width*/ - lodepng_set32bitInt(data + 4, h); /*height*/ - data[8] = (unsigned char)bitdepth; /*bit depth*/ - data[9] = (unsigned char)colortype; /*color type*/ - data[10] = 0; /*compression method*/ - data[11] = 0; /*filter method*/ - data[12] = interlace_method; /*interlace method*/ - - lodepng_chunk_generate_crc(chunk); - return 0; -} - -/* only adds the chunk if needed (there is a key or palette with alpha) */ -static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info) { - unsigned char* chunk; - size_t i, j = 8; - - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, info->palettesize * 3, "PLTE")); - - for(i = 0; i != info->palettesize; ++i) { - /*add all channels except alpha channel*/ - chunk[j++] = info->palette[i * 4 + 0]; - chunk[j++] = info->palette[i * 4 + 1]; - chunk[j++] = info->palette[i * 4 + 2]; - } - - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info) { - unsigned char* chunk = 0; - - if(info->colortype == LCT_PALETTE) { - size_t i, amount = info->palettesize; - /*the tail of palette values that all have 255 as alpha, does not have to be encoded*/ - for(i = info->palettesize; i != 0; --i) { - if(info->palette[4 * (i - 1) + 3] != 255) break; - --amount; - } - if(amount) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, amount, "tRNS")); - /*add the alpha channel values from the palette*/ - for(i = 0; i != amount; ++i) chunk[8 + i] = info->palette[4 * i + 3]; - } - } else if(info->colortype == LCT_GREY) { - if(info->key_defined) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "tRNS")); - chunk[8] = (unsigned char)(info->key_r >> 8); - chunk[9] = (unsigned char)(info->key_r & 255); - } - } else if(info->colortype == LCT_RGB) { - if(info->key_defined) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "tRNS")); - chunk[8] = (unsigned char)(info->key_r >> 8); - chunk[9] = (unsigned char)(info->key_r & 255); - chunk[10] = (unsigned char)(info->key_g >> 8); - chunk[11] = (unsigned char)(info->key_g & 255); - chunk[12] = (unsigned char)(info->key_b >> 8); - chunk[13] = (unsigned char)(info->key_b & 255); - } - } - - if(chunk) lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize, - LodePNGCompressSettings* zlibsettings) { - unsigned error = 0; - unsigned char* zlib = 0; - size_t zlibsize = 0; - - error = zlib_compress(&zlib, &zlibsize, data, datasize, zlibsettings); - if(!error) { - error = lodepng_chunk_createv(out, zlibsize, "IDAT", zlib); - } - lodepng_free(zlib); - return error; -} - -static unsigned addChunk_IEND(ucvector* out) { - return lodepng_chunk_createv(out, 0, "IEND", 0); -} - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - -static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring) { - unsigned char* chunk = 0; - size_t keysize = lodepng_strlen(keyword), textsize = lodepng_strlen(textstring); - size_t size = keysize + 1 + textsize; - if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, size, "tEXt")); - lodepng_memcpy(chunk + 8, keyword, keysize); - chunk[8 + keysize] = 0; /*null termination char*/ - lodepng_memcpy(chunk + 9 + keysize, textstring, textsize); - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring, - LodePNGCompressSettings* zlibsettings) { - unsigned error = 0; - unsigned char* chunk = 0; - unsigned char* compressed = 0; - size_t compressedsize = 0; - size_t textsize = lodepng_strlen(textstring); - size_t keysize = lodepng_strlen(keyword); - if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ - - error = zlib_compress(&compressed, &compressedsize, - (const unsigned char*)textstring, textsize, zlibsettings); - if(!error) { - size_t size = keysize + 2 + compressedsize; - error = lodepng_chunk_init(&chunk, out, size, "zTXt"); - } - if(!error) { - lodepng_memcpy(chunk + 8, keyword, keysize); - chunk[8 + keysize] = 0; /*null termination char*/ - chunk[9 + keysize] = 0; /*compression method: 0*/ - lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize); - lodepng_chunk_generate_crc(chunk); - } - - lodepng_free(compressed); - return error; -} - -static unsigned addChunk_iTXt(ucvector* out, unsigned compress, const char* keyword, const char* langtag, - const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings) { - unsigned error = 0; - unsigned char* chunk = 0; - unsigned char* compressed = 0; - size_t compressedsize = 0; - size_t textsize = lodepng_strlen(textstring); - size_t keysize = lodepng_strlen(keyword), langsize = lodepng_strlen(langtag), transsize = lodepng_strlen(transkey); - - if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ - - if(compress) { - error = zlib_compress(&compressed, &compressedsize, - (const unsigned char*)textstring, textsize, zlibsettings); - } - if(!error) { - size_t size = keysize + 3 + langsize + 1 + transsize + 1 + (compress ? compressedsize : textsize); - error = lodepng_chunk_init(&chunk, out, size, "iTXt"); - } - if(!error) { - size_t pos = 8; - lodepng_memcpy(chunk + pos, keyword, keysize); - pos += keysize; - chunk[pos++] = 0; /*null termination char*/ - chunk[pos++] = (compress ? 1 : 0); /*compression flag*/ - chunk[pos++] = 0; /*compression method: 0*/ - lodepng_memcpy(chunk + pos, langtag, langsize); - pos += langsize; - chunk[pos++] = 0; /*null termination char*/ - lodepng_memcpy(chunk + pos, transkey, transsize); - pos += transsize; - chunk[pos++] = 0; /*null termination char*/ - if(compress) { - lodepng_memcpy(chunk + pos, compressed, compressedsize); - } else { - lodepng_memcpy(chunk + pos, textstring, textsize); - } - lodepng_chunk_generate_crc(chunk); - } - - lodepng_free(compressed); - return error; -} - -static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info) { - unsigned char* chunk = 0; - if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 2, "bKGD")); - chunk[8] = (unsigned char)(info->background_r >> 8); - chunk[9] = (unsigned char)(info->background_r & 255); - } else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 6, "bKGD")); - chunk[8] = (unsigned char)(info->background_r >> 8); - chunk[9] = (unsigned char)(info->background_r & 255); - chunk[10] = (unsigned char)(info->background_g >> 8); - chunk[11] = (unsigned char)(info->background_g & 255); - chunk[12] = (unsigned char)(info->background_b >> 8); - chunk[13] = (unsigned char)(info->background_b & 255); - } else if(info->color.colortype == LCT_PALETTE) { - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 1, "bKGD")); - chunk[8] = (unsigned char)(info->background_r & 255); /*palette index*/ - } - if(chunk) lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time) { - unsigned char* chunk; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 7, "tIME")); - chunk[8] = (unsigned char)(time->year >> 8); - chunk[9] = (unsigned char)(time->year & 255); - chunk[10] = (unsigned char)time->month; - chunk[11] = (unsigned char)time->day; - chunk[12] = (unsigned char)time->hour; - chunk[13] = (unsigned char)time->minute; - chunk[14] = (unsigned char)time->second; - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info) { - unsigned char* chunk; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 9, "pHYs")); - lodepng_set32bitInt(chunk + 8, info->phys_x); - lodepng_set32bitInt(chunk + 12, info->phys_y); - chunk[16] = info->phys_unit; - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_gAMA(ucvector* out, const LodePNGInfo* info) { - unsigned char* chunk; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 4, "gAMA")); - lodepng_set32bitInt(chunk + 8, info->gama_gamma); - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_cHRM(ucvector* out, const LodePNGInfo* info) { - unsigned char* chunk; - CERROR_TRY_RETURN(lodepng_chunk_init(&chunk, out, 32, "cHRM")); - lodepng_set32bitInt(chunk + 8, info->chrm_white_x); - lodepng_set32bitInt(chunk + 12, info->chrm_white_y); - lodepng_set32bitInt(chunk + 16, info->chrm_red_x); - lodepng_set32bitInt(chunk + 20, info->chrm_red_y); - lodepng_set32bitInt(chunk + 24, info->chrm_green_x); - lodepng_set32bitInt(chunk + 28, info->chrm_green_y); - lodepng_set32bitInt(chunk + 32, info->chrm_blue_x); - lodepng_set32bitInt(chunk + 36, info->chrm_blue_y); - lodepng_chunk_generate_crc(chunk); - return 0; -} - -static unsigned addChunk_sRGB(ucvector* out, const LodePNGInfo* info) { - unsigned char data = info->srgb_intent; - return lodepng_chunk_createv(out, 1, "sRGB", &data); -} - -static unsigned addChunk_iCCP(ucvector* out, const LodePNGInfo* info, LodePNGCompressSettings* zlibsettings) { - unsigned error = 0; - unsigned char* chunk = 0; - unsigned char* compressed = 0; - size_t compressedsize = 0; - size_t keysize = lodepng_strlen(info->iccp_name); - - if(keysize < 1 || keysize > 79) return 89; /*error: invalid keyword size*/ - error = zlib_compress(&compressed, &compressedsize, - info->iccp_profile, info->iccp_profile_size, zlibsettings); - if(!error) { - size_t size = keysize + 2 + compressedsize; - error = lodepng_chunk_init(&chunk, out, size, "iCCP"); - } - if(!error) { - lodepng_memcpy(chunk + 8, info->iccp_name, keysize); - chunk[8 + keysize] = 0; /*null termination char*/ - chunk[9 + keysize] = 0; /*compression method: 0*/ - lodepng_memcpy(chunk + 10 + keysize, compressed, compressedsize); - lodepng_chunk_generate_crc(chunk); - } - - lodepng_free(compressed); - return error; -} - -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline, - size_t length, size_t bytewidth, unsigned char filterType) { - size_t i; - switch(filterType) { - case 0: /*None*/ - for(i = 0; i != length; ++i) out[i] = scanline[i]; - break; - case 1: /*Sub*/ - for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; - for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - scanline[i - bytewidth]; - break; - case 2: /*Up*/ - if(prevline) { - for(i = 0; i != length; ++i) out[i] = scanline[i] - prevline[i]; - } else { - for(i = 0; i != length; ++i) out[i] = scanline[i]; - } - break; - case 3: /*Average*/ - if(prevline) { - for(i = 0; i != bytewidth; ++i) out[i] = scanline[i] - (prevline[i] >> 1); - for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) >> 1); - } else { - for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; - for(i = bytewidth; i < length; ++i) out[i] = scanline[i] - (scanline[i - bytewidth] >> 1); - } - break; - case 4: /*Paeth*/ - if(prevline) { - /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/ - for(i = 0; i != bytewidth; ++i) out[i] = (scanline[i] - prevline[i]); - for(i = bytewidth; i < length; ++i) { - out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth])); - } - } else { - for(i = 0; i != bytewidth; ++i) out[i] = scanline[i]; - /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/ - for(i = bytewidth; i < length; ++i) out[i] = (scanline[i] - scanline[i - bytewidth]); - } - break; - default: return; /*invalid filter type given*/ - } -} - -/* integer binary logarithm, max return value is 31 */ -static size_t ilog2(size_t i) { - size_t result = 0; - if(i >= 65536) { result += 16; i >>= 16; } - if(i >= 256) { result += 8; i >>= 8; } - if(i >= 16) { result += 4; i >>= 4; } - if(i >= 4) { result += 2; i >>= 2; } - if(i >= 2) { result += 1; /*i >>= 1;*/ } - return result; -} - -/* integer approximation for i * log2(i), helper function for LFS_ENTROPY */ -static size_t ilog2i(size_t i) { - size_t l; - if(i == 0) return 0; - l = ilog2(i); - /* approximate i*log2(i): l is integer logarithm, ((i - (1u << l)) << 1u) - linearly approximates the missing fractional part multiplied by i */ - return i * l + ((i - (1u << l)) << 1u); -} - -static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, - const LodePNGColorMode* color, const LodePNGEncoderSettings* settings) { - /* - For PNG filter method 0 - out must be a buffer with as size: h + (w * h * bpp + 7u) / 8u, because there are - the scanlines with 1 extra byte per scanline - */ - - unsigned bpp = lodepng_get_bpp(color); - /*the width of a scanline in bytes, not including the filter type*/ - size_t linebytes = lodepng_get_raw_size_idat(w, 1, bpp) - 1u; - - /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/ - size_t bytewidth = (bpp + 7u) / 8u; - const unsigned char* prevline = 0; - unsigned x, y; - unsigned error = 0; - LodePNGFilterStrategy strategy = settings->filter_strategy; - - /* - There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard: - * If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e. - use fixed filtering, with the filter None). - * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is - not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply - all five filters and select the filter that produces the smallest sum of absolute values per row. - This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true. - - If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed, - but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum - heuristic is used. - */ - if(settings->filter_palette_zero && - (color->colortype == LCT_PALETTE || color->bitdepth < 8)) strategy = LFS_ZERO; - - if(bpp == 0) return 31; /*error: invalid color type*/ - - if(strategy >= LFS_ZERO && strategy <= LFS_FOUR) { - unsigned char type = (unsigned char)strategy; - for(y = 0; y != h; ++y) { - size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ - size_t inindex = linebytes * y; - out[outindex] = type; /*filter type byte*/ - filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type); - prevline = &in[inindex]; - } - } else if(strategy == LFS_MINSUM) { - /*adaptive filtering*/ - unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ - size_t smallest = 0; - unsigned char type, bestType = 0; - - for(type = 0; type != 5; ++type) { - attempt[type] = (unsigned char*)lodepng_malloc(linebytes); - if(!attempt[type]) error = 83; /*alloc fail*/ - } - - if(!error) { - for(y = 0; y != h; ++y) { - /*try the 5 filter types*/ - for(type = 0; type != 5; ++type) { - size_t sum = 0; - filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); - - /*calculate the sum of the result*/ - if(type == 0) { - for(x = 0; x != linebytes; ++x) sum += (unsigned char)(attempt[type][x]); - } else { - for(x = 0; x != linebytes; ++x) { - /*For differences, each byte should be treated as signed, values above 127 are negative - (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there. - This means filtertype 0 is almost never chosen, but that is justified.*/ - unsigned char s = attempt[type][x]; - sum += s < 128 ? s : (255U - s); - } - } - - /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/ - if(type == 0 || sum < smallest) { - bestType = type; - smallest = sum; - } - } - - prevline = &in[y * linebytes]; - - /*now fill the out values*/ - out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ - for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; - } - } - - for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); - } else if(strategy == LFS_ENTROPY) { - unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ - size_t bestSum = 0; - unsigned type, bestType = 0; - unsigned count[256]; - - for(type = 0; type != 5; ++type) { - attempt[type] = (unsigned char*)lodepng_malloc(linebytes); - if(!attempt[type]) error = 83; /*alloc fail*/ - } - - if(!error) { - for(y = 0; y != h; ++y) { - /*try the 5 filter types*/ - for(type = 0; type != 5; ++type) { - size_t sum = 0; - filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); - lodepng_memset(count, 0, 256 * sizeof(*count)); - for(x = 0; x != linebytes; ++x) ++count[attempt[type][x]]; - ++count[type]; /*the filter type itself is part of the scanline*/ - for(x = 0; x != 256; ++x) { - sum += ilog2i(count[x]); - } - /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/ - if(type == 0 || sum > bestSum) { - bestType = type; - bestSum = sum; - } - } - - prevline = &in[y * linebytes]; - - /*now fill the out values*/ - out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ - for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; - } - } - - for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); - } else if(strategy == LFS_PREDEFINED) { - for(y = 0; y != h; ++y) { - size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/ - size_t inindex = linebytes * y; - unsigned char type = settings->predefined_filters[y]; - out[outindex] = type; /*filter type byte*/ - filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type); - prevline = &in[inindex]; - } - } else if(strategy == LFS_BRUTE_FORCE) { - /*brute force filter chooser. - deflate the scanline after every filter attempt to see which one deflates best. - This is very slow and gives only slightly smaller, sometimes even larger, result*/ - size_t size[5]; - unsigned char* attempt[5]; /*five filtering attempts, one for each filter type*/ - size_t smallest = 0; - unsigned type = 0, bestType = 0; - unsigned char* dummy; - LodePNGCompressSettings zlibsettings; - lodepng_memcpy(&zlibsettings, &settings->zlibsettings, sizeof(LodePNGCompressSettings)); - /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose, - to simulate the true case where the tree is the same for the whole image. Sometimes it gives - better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare - cases better compression. It does make this a bit less slow, so it's worth doing this.*/ - zlibsettings.btype = 1; - /*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG - images only, so disable it*/ - zlibsettings.custom_zlib = 0; - zlibsettings.custom_deflate = 0; - for(type = 0; type != 5; ++type) { - attempt[type] = (unsigned char*)lodepng_malloc(linebytes); - if(!attempt[type]) error = 83; /*alloc fail*/ - } - if(!error) { - for(y = 0; y != h; ++y) /*try the 5 filter types*/ { - for(type = 0; type != 5; ++type) { - unsigned testsize = (unsigned)linebytes; - /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/ - - filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type); - size[type] = 0; - dummy = 0; - zlib_compress(&dummy, &size[type], attempt[type], testsize, &zlibsettings); - lodepng_free(dummy); - /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/ - if(type == 0 || size[type] < smallest) { - bestType = type; - smallest = size[type]; - } - } - prevline = &in[y * linebytes]; - out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/ - for(x = 0; x != linebytes; ++x) out[y * (linebytes + 1) + 1 + x] = attempt[bestType][x]; - } - } - for(type = 0; type != 5; ++type) lodepng_free(attempt[type]); - } - else return 88; /* unknown filter strategy */ - - return error; -} - -static void addPaddingBits(unsigned char* out, const unsigned char* in, - size_t olinebits, size_t ilinebits, unsigned h) { - /*The opposite of the removePaddingBits function - olinebits must be >= ilinebits*/ - unsigned y; - size_t diff = olinebits - ilinebits; - size_t obp = 0, ibp = 0; /*bit pointers*/ - for(y = 0; y != h; ++y) { - size_t x; - for(x = 0; x < ilinebits; ++x) { - unsigned char bit = readBitFromReversedStream(&ibp, in); - setBitOfReversedStream(&obp, out, bit); - } - /*obp += diff; --> no, fill in some value in the padding bits too, to avoid - "Use of uninitialised value of size ###" warning from valgrind*/ - for(x = 0; x != diff; ++x) setBitOfReversedStream(&obp, out, 0); - } -} - -/* -in: non-interlaced image with size w*h -out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with - no padding bits between scanlines, but between reduced images so that each - reduced image starts at a byte. -bpp: bits per pixel -there are no padding bits, not between scanlines, not between reduced images -in has the following size in bits: w * h * bpp. -out is possibly bigger due to padding bits between reduced images -NOTE: comments about padding bits are only relevant if bpp < 8 -*/ -static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp) { - unsigned passw[7], passh[7]; - size_t filter_passstart[8], padded_passstart[8], passstart[8]; - unsigned i; - - Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); - - if(bpp >= 8) { - for(i = 0; i != 7; ++i) { - unsigned x, y, b; - size_t bytewidth = bpp / 8u; - for(y = 0; y < passh[i]; ++y) - for(x = 0; x < passw[i]; ++x) { - size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth; - size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth; - for(b = 0; b < bytewidth; ++b) { - out[pixeloutstart + b] = in[pixelinstart + b]; - } - } - } - } else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/ { - for(i = 0; i != 7; ++i) { - unsigned x, y, b; - unsigned ilinebits = bpp * passw[i]; - unsigned olinebits = bpp * w; - size_t obp, ibp; /*bit pointers (for out and in buffer)*/ - for(y = 0; y < passh[i]; ++y) - for(x = 0; x < passw[i]; ++x) { - ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp; - obp = (8 * passstart[i]) + (y * ilinebits + x * bpp); - for(b = 0; b < bpp; ++b) { - unsigned char bit = readBitFromReversedStream(&ibp, in); - setBitOfReversedStream(&obp, out, bit); - } - } - } - } -} - -/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image. -return value is error**/ -static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in, - unsigned w, unsigned h, - const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings) { - /* - This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps: - *) if no Adam7: 1) add padding bits (= possible extra bits per scanline if bpp < 8) 2) filter - *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter - */ - unsigned bpp = lodepng_get_bpp(&info_png->color); - unsigned error = 0; - - if(info_png->interlace_method == 0) { - *outsize = h + (h * ((w * bpp + 7u) / 8u)); /*image size plus an extra byte per scanline + possible padding bits*/ - *out = (unsigned char*)lodepng_malloc(*outsize); - if(!(*out) && (*outsize)) error = 83; /*alloc fail*/ - - if(!error) { - /*non multiple of 8 bits per scanline, padding bits needed per scanline*/ - if(bpp < 8 && w * bpp != ((w * bpp + 7u) / 8u) * 8u) { - unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7u) / 8u)); - if(!padded) error = 83; /*alloc fail*/ - if(!error) { - addPaddingBits(padded, in, ((w * bpp + 7u) / 8u) * 8u, w * bpp, h); - error = filter(*out, padded, w, h, &info_png->color, settings); - } - lodepng_free(padded); - } else { - /*we can immediately filter into the out buffer, no other steps needed*/ - error = filter(*out, in, w, h, &info_png->color, settings); - } - } - } else /*interlace_method is 1 (Adam7)*/ { - unsigned passw[7], passh[7]; - size_t filter_passstart[8], padded_passstart[8], passstart[8]; - unsigned char* adam7; - - Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp); - - *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/ - *out = (unsigned char*)lodepng_malloc(*outsize); - if(!(*out)) error = 83; /*alloc fail*/ - - adam7 = (unsigned char*)lodepng_malloc(passstart[7]); - if(!adam7 && passstart[7]) error = 83; /*alloc fail*/ - - if(!error) { - unsigned i; - - Adam7_interlace(adam7, in, w, h, bpp); - for(i = 0; i != 7; ++i) { - if(bpp < 8) { - unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]); - if(!padded) ERROR_BREAK(83); /*alloc fail*/ - addPaddingBits(padded, &adam7[passstart[i]], - ((passw[i] * bpp + 7u) / 8u) * 8u, passw[i] * bpp, passh[i]); - error = filter(&(*out)[filter_passstart[i]], padded, - passw[i], passh[i], &info_png->color, settings); - lodepng_free(padded); - } else { - error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]], - passw[i], passh[i], &info_png->color, settings); - } - - if(error) break; - } - } - - lodepng_free(adam7); - } - - return error; -} - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS -static unsigned addUnknownChunks(ucvector* out, unsigned char* data, size_t datasize) { - unsigned char* inchunk = data; - while((size_t)(inchunk - data) < datasize) { - CERROR_TRY_RETURN(lodepng_chunk_append(&out->data, &out->size, inchunk)); - out->allocsize = out->size; /*fix the allocsize again*/ - inchunk = lodepng_chunk_next(inchunk, data + datasize); - } - return 0; -} - -static unsigned isGrayICCProfile(const unsigned char* profile, unsigned size) { - /* - It is a gray profile if bytes 16-19 are "GRAY", rgb profile if bytes 16-19 - are "RGB ". We do not perform any full parsing of the ICC profile here, other - than check those 4 bytes to grayscale profile. Other than that, validity of - the profile is not checked. This is needed only because the PNG specification - requires using a non-gray color model if there is an ICC profile with "RGB " - (sadly limiting compression opportunities if the input data is grayscale RGB - data), and requires using a gray color model if it is "GRAY". - */ - if(size < 20) return 0; - return profile[16] == 'G' && profile[17] == 'R' && profile[18] == 'A' && profile[19] == 'Y'; -} - -static unsigned isRGBICCProfile(const unsigned char* profile, unsigned size) { - /* See comment in isGrayICCProfile*/ - if(size < 20) return 0; - return profile[16] == 'R' && profile[17] == 'G' && profile[18] == 'B' && profile[19] == ' '; -} -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -unsigned lodepng_encode(unsigned char** out, size_t* outsize, - const unsigned char* image, unsigned w, unsigned h, - LodePNGState* state) { - unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/ - size_t datasize = 0; - ucvector outv = ucvector_init(NULL, 0); - LodePNGInfo info; - const LodePNGInfo* info_png = &state->info_png; - - lodepng_info_init(&info); - - /*provide some proper output values if error will happen*/ - *out = 0; - *outsize = 0; - state->error = 0; - - /*check input values validity*/ - if((info_png->color.colortype == LCT_PALETTE || state->encoder.force_palette) - && (info_png->color.palettesize == 0 || info_png->color.palettesize > 256)) { - state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/ - goto cleanup; - } - if(state->encoder.zlibsettings.btype > 2) { - state->error = 61; /*error: invalid btype*/ - goto cleanup; - } - if(info_png->interlace_method > 1) { - state->error = 71; /*error: invalid interlace mode*/ - goto cleanup; - } - state->error = checkColorValidity(info_png->color.colortype, info_png->color.bitdepth); - if(state->error) goto cleanup; /*error: invalid color type given*/ - state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth); - if(state->error) goto cleanup; /*error: invalid color type given*/ - - /* color convert and compute scanline filter types */ - lodepng_info_copy(&info, &state->info_png); - if(state->encoder.auto_convert) { - LodePNGColorStats stats; - lodepng_color_stats_init(&stats); -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - if(info_png->iccp_defined && - isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) { - /*the PNG specification does not allow to use palette with a GRAY ICC profile, even - if the palette has only gray colors, so disallow it.*/ - stats.allow_palette = 0; - } - if(info_png->iccp_defined && - isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size)) { - /*the PNG specification does not allow to use grayscale color with RGB ICC profile, so disallow gray.*/ - stats.allow_greyscale = 0; - } -#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ - state->error = lodepng_compute_color_stats(&stats, image, w, h, &state->info_raw); - if(state->error) goto cleanup; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - if(info_png->background_defined) { - /*the background chunk's color must be taken into account as well*/ - unsigned r = 0, g = 0, b = 0; - LodePNGColorMode mode16 = lodepng_color_mode_make(LCT_RGB, 16); - lodepng_convert_rgb(&r, &g, &b, info_png->background_r, info_png->background_g, info_png->background_b, &mode16, &info_png->color); - state->error = lodepng_color_stats_add(&stats, r, g, b, 65535); - if(state->error) goto cleanup; - } -#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ - state->error = auto_choose_color(&info.color, &state->info_raw, &stats); - if(state->error) goto cleanup; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*also convert the background chunk*/ - if(info_png->background_defined) { - if(lodepng_convert_rgb(&info.background_r, &info.background_g, &info.background_b, - info_png->background_r, info_png->background_g, info_png->background_b, &info.color, &info_png->color)) { - state->error = 104; - goto cleanup; - } - } -#endif /* LODEPNG_COMPILE_ANCILLARY_CHUNKS */ - } -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - if(info_png->iccp_defined) { - unsigned gray_icc = isGrayICCProfile(info_png->iccp_profile, info_png->iccp_profile_size); - unsigned rgb_icc = isRGBICCProfile(info_png->iccp_profile, info_png->iccp_profile_size); - unsigned gray_png = info.color.colortype == LCT_GREY || info.color.colortype == LCT_GREY_ALPHA; - if(!gray_icc && !rgb_icc) { - state->error = 100; /* Disallowed profile color type for PNG */ - goto cleanup; - } - if(gray_icc != gray_png) { - /*Not allowed to use RGB/RGBA/palette with GRAY ICC profile or vice versa, - or in case of auto_convert, it wasn't possible to find appropriate model*/ - state->error = state->encoder.auto_convert ? 102 : 101; - goto cleanup; - } - } -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - if(!lodepng_color_mode_equal(&state->info_raw, &info.color)) { - unsigned char* converted; - size_t size = ((size_t)w * (size_t)h * (size_t)lodepng_get_bpp(&info.color) + 7u) / 8u; - - converted = (unsigned char*)lodepng_malloc(size); - if(!converted && size) state->error = 83; /*alloc fail*/ - if(!state->error) { - state->error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h); - } - if(!state->error) { - state->error = preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder); - } - lodepng_free(converted); - if(state->error) goto cleanup; - } else { - state->error = preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder); - if(state->error) goto cleanup; - } - - /* output all PNG chunks */ { -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - size_t i; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - /*write signature and chunks*/ - state->error = writeSignature(&outv); - if(state->error) goto cleanup; - /*IHDR*/ - state->error = addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method); - if(state->error) goto cleanup; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*unknown chunks between IHDR and PLTE*/ - if(info.unknown_chunks_data[0]) { - state->error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]); - if(state->error) goto cleanup; - } - /*color profile chunks must come before PLTE */ - if(info.iccp_defined) { - state->error = addChunk_iCCP(&outv, &info, &state->encoder.zlibsettings); - if(state->error) goto cleanup; - } - if(info.srgb_defined) { - state->error = addChunk_sRGB(&outv, &info); - if(state->error) goto cleanup; - } - if(info.gama_defined) { - state->error = addChunk_gAMA(&outv, &info); - if(state->error) goto cleanup; - } - if(info.chrm_defined) { - state->error = addChunk_cHRM(&outv, &info); - if(state->error) goto cleanup; - } -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - /*PLTE*/ - if(info.color.colortype == LCT_PALETTE) { - state->error = addChunk_PLTE(&outv, &info.color); - if(state->error) goto cleanup; - } - if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA)) { - /*force_palette means: write suggested palette for truecolor in PLTE chunk*/ - state->error = addChunk_PLTE(&outv, &info.color); - if(state->error) goto cleanup; - } - /*tRNS (this will only add if when necessary) */ - state->error = addChunk_tRNS(&outv, &info.color); - if(state->error) goto cleanup; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*bKGD (must come between PLTE and the IDAt chunks*/ - if(info.background_defined) { - state->error = addChunk_bKGD(&outv, &info); - if(state->error) goto cleanup; - } - /*pHYs (must come before the IDAT chunks)*/ - if(info.phys_defined) { - state->error = addChunk_pHYs(&outv, &info); - if(state->error) goto cleanup; - } - - /*unknown chunks between PLTE and IDAT*/ - if(info.unknown_chunks_data[1]) { - state->error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]); - if(state->error) goto cleanup; - } -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - /*IDAT (multiple IDAT chunks must be consecutive)*/ - state->error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings); - if(state->error) goto cleanup; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*tIME*/ - if(info.time_defined) { - state->error = addChunk_tIME(&outv, &info.time); - if(state->error) goto cleanup; - } - /*tEXt and/or zTXt*/ - for(i = 0; i != info.text_num; ++i) { - if(lodepng_strlen(info.text_keys[i]) > 79) { - state->error = 66; /*text chunk too large*/ - goto cleanup; - } - if(lodepng_strlen(info.text_keys[i]) < 1) { - state->error = 67; /*text chunk too small*/ - goto cleanup; - } - if(state->encoder.text_compression) { - state->error = addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings); - if(state->error) goto cleanup; - } else { - state->error = addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]); - if(state->error) goto cleanup; - } - } - /*LodePNG version id in text chunk*/ - if(state->encoder.add_id) { - unsigned already_added_id_text = 0; - for(i = 0; i != info.text_num; ++i) { - const char* k = info.text_keys[i]; - /* Could use strcmp, but we're not calling or reimplementing this C library function for this use only */ - if(k[0] == 'L' && k[1] == 'o' && k[2] == 'd' && k[3] == 'e' && - k[4] == 'P' && k[5] == 'N' && k[6] == 'G' && k[7] == '\0') { - already_added_id_text = 1; - break; - } - } - if(already_added_id_text == 0) { - state->error = addChunk_tEXt(&outv, "LodePNG", LODEPNG_VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/ - if(state->error) goto cleanup; - } - } - /*iTXt*/ - for(i = 0; i != info.itext_num; ++i) { - if(lodepng_strlen(info.itext_keys[i]) > 79) { - state->error = 66; /*text chunk too large*/ - goto cleanup; - } - if(lodepng_strlen(info.itext_keys[i]) < 1) { - state->error = 67; /*text chunk too small*/ - goto cleanup; - } - state->error = addChunk_iTXt( - &outv, state->encoder.text_compression, - info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i], - &state->encoder.zlibsettings); - if(state->error) goto cleanup; - } - - /*unknown chunks between IDAT and IEND*/ - if(info.unknown_chunks_data[2]) { - state->error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]); - if(state->error) goto cleanup; - } -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - state->error = addChunk_IEND(&outv); - if(state->error) goto cleanup; - } - -cleanup: - lodepng_info_cleanup(&info); - lodepng_free(data); - - /*instead of cleaning the vector up, give it to the output*/ - *out = outv.data; - *outsize = outv.size; - - return state->error; -} - -unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image, - unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth) { - unsigned error; - LodePNGState state; - lodepng_state_init(&state); - state.info_raw.colortype = colortype; - state.info_raw.bitdepth = bitdepth; - state.info_png.color.colortype = colortype; - state.info_png.color.bitdepth = bitdepth; - lodepng_encode(out, outsize, image, w, h, &state); - error = state.error; - lodepng_state_cleanup(&state); - return error; -} - -unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) { - return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8); -} - -unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h) { - return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8); -} - -#ifdef LODEPNG_COMPILE_DISK -unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth) { - unsigned char* buffer; - size_t buffersize; - unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth); - if(!error) error = lodepng_save_file(buffer, buffersize, filename); - lodepng_free(buffer); - return error; -} - -unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { - return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8); -} - -unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h) { - return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8); -} -#endif /*LODEPNG_COMPILE_DISK*/ - -void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings) { - lodepng_compress_settings_init(&settings->zlibsettings); - settings->filter_palette_zero = 1; - settings->filter_strategy = LFS_MINSUM; - settings->auto_convert = 1; - settings->force_palette = 0; - settings->predefined_filters = 0; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - settings->add_id = 0; - settings->text_compression = 1; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} - -#endif /*LODEPNG_COMPILE_ENCODER*/ -#endif /*LODEPNG_COMPILE_PNG*/ - -#ifdef LODEPNG_COMPILE_ERROR_TEXT -/* -This returns the description of a numerical error code in English. This is also -the documentation of all the error codes. -*/ -const char* lodepng_error_text(unsigned code) { - switch(code) { - case 0: return "no error, everything went ok"; - case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/ - case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/ - case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/ - case 13: return "problem while processing dynamic deflate block"; - case 14: return "problem while processing dynamic deflate block"; - case 15: return "problem while processing dynamic deflate block"; - /*this error could happen if there are only 0 or 1 symbols present in the huffman code:*/ - case 16: return "invalid code while processing dynamic deflate block"; - case 17: return "end of out buffer memory reached while inflating"; - case 18: return "invalid distance code while inflating"; - case 19: return "end of out buffer memory reached while inflating"; - case 20: return "invalid deflate block BTYPE encountered while decoding"; - case 21: return "NLEN is not ones complement of LEN in a deflate block"; - - /*end of out buffer memory reached while inflating: - This can happen if the inflated deflate data is longer than the amount of bytes required to fill up - all the pixels of the image, given the color depth and image dimensions. Something that doesn't - happen in a normal, well encoded, PNG image.*/ - case 22: return "end of out buffer memory reached while inflating"; - case 23: return "end of in buffer memory reached while inflating"; - case 24: return "invalid FCHECK in zlib header"; - case 25: return "invalid compression method in zlib header"; - case 26: return "FDICT encountered in zlib header while it's not used for PNG"; - case 27: return "PNG file is smaller than a PNG header"; - /*Checks the magic file header, the first 8 bytes of the PNG file*/ - case 28: return "incorrect PNG signature, it's no PNG or corrupted"; - case 29: return "first chunk is not the header chunk"; - case 30: return "chunk length too large, chunk broken off at end of file"; - case 31: return "illegal PNG color type or bpp"; - case 32: return "illegal PNG compression method"; - case 33: return "illegal PNG filter method"; - case 34: return "illegal PNG interlace method"; - case 35: return "chunk length of a chunk is too large or the chunk too small"; - case 36: return "illegal PNG filter type encountered"; - case 37: return "illegal bit depth for this color type given"; - case 38: return "the palette is too small or too big"; /*0, or more than 256 colors*/ - case 39: return "tRNS chunk before PLTE or has more entries than palette size"; - case 40: return "tRNS chunk has wrong size for grayscale image"; - case 41: return "tRNS chunk has wrong size for RGB image"; - case 42: return "tRNS chunk appeared while it was not allowed for this color type"; - case 43: return "bKGD chunk has wrong size for palette image"; - case 44: return "bKGD chunk has wrong size for grayscale image"; - case 45: return "bKGD chunk has wrong size for RGB image"; - case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?"; - case 49: return "jumped past memory while generating dynamic huffman tree"; - case 50: return "jumped past memory while generating dynamic huffman tree"; - case 51: return "jumped past memory while inflating huffman block"; - case 52: return "jumped past memory while inflating"; - case 53: return "size of zlib data too small"; - case 54: return "repeat symbol in tree while there was no value symbol yet"; - /*jumped past tree while generating huffman tree, this could be when the - tree will have more leaves than symbols after generating it out of the - given lengths. They call this an oversubscribed dynamic bit lengths tree in zlib.*/ - case 55: return "jumped past tree while generating huffman tree"; - case 56: return "given output image colortype or bitdepth not supported for color conversion"; - case 57: return "invalid CRC encountered (checking CRC can be disabled)"; - case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)"; - case 59: return "requested color conversion not supported"; - case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)"; - case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)"; - /*LodePNG leaves the choice of RGB to grayscale conversion formula to the user.*/ - case 62: return "conversion from color to grayscale not supported"; - /*(2^31-1)*/ - case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk"; - /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/ - case 64: return "the length of the END symbol 256 in the Huffman tree is 0"; - case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes"; - case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte"; - case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors"; - case 69: return "unknown chunk type with 'critical' flag encountered by the decoder"; - case 71: return "invalid interlace mode given to encoder (must be 0 or 1)"; - case 72: return "while decoding, invalid compression method encountering in zTXt or iTXt chunk (it must be 0)"; - case 73: return "invalid tIME chunk size"; - case 74: return "invalid pHYs chunk size"; - /*length could be wrong, or data chopped off*/ - case 75: return "no null termination char found while decoding text chunk"; - case 76: return "iTXt chunk too short to contain required bytes"; - case 77: return "integer overflow in buffer size"; - case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/ - case 79: return "failed to open file for writing"; - case 80: return "tried creating a tree of 0 symbols"; - case 81: return "lazy matching at pos 0 is impossible"; - case 82: return "color conversion to palette requested while a color isn't in palette, or index out of bounds"; - case 83: return "memory allocation failed"; - case 84: return "given image too small to contain all pixels to be encoded"; - case 86: return "impossible offset in lz77 encoding (internal bug)"; - case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined"; - case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy"; - case 89: return "text chunk keyword too short or long: must have size 1-79"; - /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/ - case 90: return "windowsize must be a power of two"; - case 91: return "invalid decompressed idat size"; - case 92: return "integer overflow due to too many pixels"; - case 93: return "zero width or height is invalid"; - case 94: return "header chunk must have a size of 13 bytes"; - case 95: return "integer overflow with combined idat chunk size"; - case 96: return "invalid gAMA chunk size"; - case 97: return "invalid cHRM chunk size"; - case 98: return "invalid sRGB chunk size"; - case 99: return "invalid sRGB rendering intent"; - case 100: return "invalid ICC profile color type, the PNG specification only allows RGB or GRAY"; - case 101: return "PNG specification does not allow RGB ICC profile on gray color types and vice versa"; - case 102: return "not allowed to set grayscale ICC profile with colored pixels by PNG specification"; - case 103: return "invalid palette index in bKGD chunk. Maybe it came before PLTE chunk?"; - case 104: return "invalid bKGD color while encoding (e.g. palette index out of range)"; - case 105: return "integer overflow of bitsize"; - case 106: return "PNG file must have PLTE chunk if color type is palette"; - case 107: return "color convert from palette mode requested without setting the palette data in it"; - case 108: return "tried to add more than 256 values to a palette"; - /*this limit can be configured in LodePNGDecompressSettings*/ - case 109: return "tried to decompress zlib or deflate data larger than desired max_output_size"; - case 110: return "custom zlib or inflate decompression failed"; - case 111: return "custom zlib or deflate compression failed"; - /*max text size limit can be configured in LodePNGDecoderSettings. This error prevents - unreasonable memory consumption when decoding due to impossibly large text sizes.*/ - case 112: return "compressed text unreasonably large"; - /*max ICC size limit can be configured in LodePNGDecoderSettings. This error prevents - unreasonable memory consumption when decoding due to impossibly large ICC profile*/ - case 113: return "ICC profile unreasonably large"; - } - return "unknown error code"; -} -#endif /*LODEPNG_COMPILE_ERROR_TEXT*/ - -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* // C++ Wrapper // */ -/* ////////////////////////////////////////////////////////////////////////// */ -/* ////////////////////////////////////////////////////////////////////////// */ - -#ifdef LODEPNG_COMPILE_CPP -namespace lodepng { - -#ifdef LODEPNG_COMPILE_DISK -unsigned load_file(std::vector& buffer, const std::string& filename) { - long size = lodepng_filesize(filename.c_str()); - if(size < 0) return 78; - buffer.resize((size_t)size); - return size == 0 ? 0 : lodepng_buffer_file(&buffer[0], (size_t)size, filename.c_str()); -} - -/*write given buffer to the file, overwriting the file, it doesn't append to it.*/ -unsigned save_file(const std::vector& buffer, const std::string& filename) { - return lodepng_save_file(buffer.empty() ? 0 : &buffer[0], buffer.size(), filename.c_str()); -} -#endif /* LODEPNG_COMPILE_DISK */ - -#ifdef LODEPNG_COMPILE_ZLIB -#ifdef LODEPNG_COMPILE_DECODER -unsigned decompress(std::vector& out, const unsigned char* in, size_t insize, - const LodePNGDecompressSettings& settings) { - unsigned char* buffer = 0; - size_t buffersize = 0; - unsigned error = zlib_decompress(&buffer, &buffersize, 0, in, insize, &settings); - if(buffer) { - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - lodepng_free(buffer); - } - return error; -} - -unsigned decompress(std::vector& out, const std::vector& in, - const LodePNGDecompressSettings& settings) { - return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings); -} -#endif /* LODEPNG_COMPILE_DECODER */ - -#ifdef LODEPNG_COMPILE_ENCODER -unsigned compress(std::vector& out, const unsigned char* in, size_t insize, - const LodePNGCompressSettings& settings) { - unsigned char* buffer = 0; - size_t buffersize = 0; - unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings); - if(buffer) { - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - lodepng_free(buffer); - } - return error; -} - -unsigned compress(std::vector& out, const std::vector& in, - const LodePNGCompressSettings& settings) { - return compress(out, in.empty() ? 0 : &in[0], in.size(), settings); -} -#endif /* LODEPNG_COMPILE_ENCODER */ -#endif /* LODEPNG_COMPILE_ZLIB */ - - -#ifdef LODEPNG_COMPILE_PNG - -State::State() { - lodepng_state_init(this); -} - -State::State(const State& other) { - lodepng_state_init(this); - lodepng_state_copy(this, &other); -} - -State::~State() { - lodepng_state_cleanup(this); -} - -State& State::operator=(const State& other) { - lodepng_state_copy(this, &other); - return *this; -} - -#ifdef LODEPNG_COMPILE_DECODER - -unsigned decode(std::vector& out, unsigned& w, unsigned& h, const unsigned char* in, - size_t insize, LodePNGColorType colortype, unsigned bitdepth) { - unsigned char* buffer = 0; - unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth); - if(buffer && !error) { - State state; - state.info_raw.colortype = colortype; - state.info_raw.bitdepth = bitdepth; - size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw); - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - } - lodepng_free(buffer); - return error; -} - -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - const std::vector& in, LodePNGColorType colortype, unsigned bitdepth) { - return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth); -} - -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - State& state, - const unsigned char* in, size_t insize) { - unsigned char* buffer = NULL; - unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize); - if(buffer && !error) { - size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw); - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - } - lodepng_free(buffer); - return error; -} - -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - State& state, - const std::vector& in) { - return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size()); -} - -#ifdef LODEPNG_COMPILE_DISK -unsigned decode(std::vector& out, unsigned& w, unsigned& h, const std::string& filename, - LodePNGColorType colortype, unsigned bitdepth) { - std::vector buffer; - /* safe output values in case error happens */ - w = h = 0; - unsigned error = load_file(buffer, filename); - if(error) return error; - return decode(out, w, h, buffer, colortype, bitdepth); -} -#endif /* LODEPNG_COMPILE_DECODER */ -#endif /* LODEPNG_COMPILE_DISK */ - -#ifdef LODEPNG_COMPILE_ENCODER -unsigned encode(std::vector& out, const unsigned char* in, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth) { - unsigned char* buffer; - size_t buffersize; - unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth); - if(buffer) { - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - lodepng_free(buffer); - } - return error; -} - -unsigned encode(std::vector& out, - const std::vector& in, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth) { - if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; - return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); -} - -unsigned encode(std::vector& out, - const unsigned char* in, unsigned w, unsigned h, - State& state) { - unsigned char* buffer; - size_t buffersize; - unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state); - if(buffer) { - out.insert(out.end(), &buffer[0], &buffer[buffersize]); - lodepng_free(buffer); - } - return error; -} - -unsigned encode(std::vector& out, - const std::vector& in, unsigned w, unsigned h, - State& state) { - if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84; - return encode(out, in.empty() ? 0 : &in[0], w, h, state); -} - -#ifdef LODEPNG_COMPILE_DISK -unsigned encode(const std::string& filename, - const unsigned char* in, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth) { - std::vector buffer; - unsigned error = encode(buffer, in, w, h, colortype, bitdepth); - if(!error) error = save_file(buffer, filename); - return error; -} - -unsigned encode(const std::string& filename, - const std::vector& in, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth) { - if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84; - return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth); -} -#endif /* LODEPNG_COMPILE_DISK */ -#endif /* LODEPNG_COMPILE_ENCODER */ -#endif /* LODEPNG_COMPILE_PNG */ -} /* namespace lodepng */ -#endif /*LODEPNG_COMPILE_CPP*/ diff --git a/third_party/lodepng/lodepng.h b/third_party/lodepng/lodepng.h deleted file mode 100644 index 685e7850..00000000 --- a/third_party/lodepng/lodepng.h +++ /dev/null @@ -1,2020 +0,0 @@ -/* -LodePNG version 20220109 - -Copyright (c) 2005-2022 Lode Vandevenne - -This software is provided 'as-is', without any express or implied -warranty. In no event will the authors be held liable for any damages -arising from the use of this software. - -Permission is granted to anyone to use this software for any purpose, -including commercial applications, and to alter it and redistribute it -freely, subject to the following restrictions: - - 1. The origin of this software must not be misrepresented; you must not - claim that you wrote the original software. If you use this software - in a product, an acknowledgment in the product documentation would be - appreciated but is not required. - - 2. Altered source versions must be plainly marked as such, and must not be - misrepresented as being the original software. - - 3. This notice may not be removed or altered from any source - distribution. -*/ - -#ifndef LODEPNG_H -#define LODEPNG_H - -#include /*for size_t*/ - -extern const char* LODEPNG_VERSION_STRING; - -/* -The following #defines are used to create code sections. They can be disabled -to disable code sections, which can give faster compile time and smaller binary. -The "NO_COMPILE" defines are designed to be used to pass as defines to the -compiler command to disable them without modifying this header, e.g. --DLODEPNG_NO_COMPILE_ZLIB for gcc. -In addition to those below, you can also define LODEPNG_NO_COMPILE_CRC to -allow implementing a custom lodepng_crc32. -*/ -/*deflate & zlib. If disabled, you must specify alternative zlib functions in -the custom_zlib field of the compress and decompress settings*/ -#ifndef LODEPNG_NO_COMPILE_ZLIB -#define LODEPNG_COMPILE_ZLIB -#endif - -/*png encoder and png decoder*/ -#ifndef LODEPNG_NO_COMPILE_PNG -#define LODEPNG_COMPILE_PNG -#endif - -/*deflate&zlib decoder and png decoder*/ -#ifndef LODEPNG_NO_COMPILE_DECODER -#define LODEPNG_COMPILE_DECODER -#endif - -/*deflate&zlib encoder and png encoder*/ -#ifndef LODEPNG_NO_COMPILE_ENCODER -#define LODEPNG_COMPILE_ENCODER -#endif - -/*the optional built in harddisk file loading and saving functions*/ -#ifndef LODEPNG_NO_COMPILE_DISK -#define LODEPNG_COMPILE_DISK -#endif - -/*support for chunks other than IHDR, IDAT, PLTE, tRNS, IEND: ancillary and unknown chunks*/ -#ifndef LODEPNG_NO_COMPILE_ANCILLARY_CHUNKS -#define LODEPNG_COMPILE_ANCILLARY_CHUNKS -#endif - -/*ability to convert error numerical codes to English text string*/ -#ifndef LODEPNG_NO_COMPILE_ERROR_TEXT -#define LODEPNG_COMPILE_ERROR_TEXT -#endif - -/*Compile the default allocators (C's free, malloc and realloc). If you disable this, -you can define the functions lodepng_free, lodepng_malloc and lodepng_realloc in your -source files with custom allocators.*/ -#ifndef LODEPNG_NO_COMPILE_ALLOCATORS -#define LODEPNG_COMPILE_ALLOCATORS -#endif - -/*compile the C++ version (you can disable the C++ wrapper here even when compiling for C++)*/ -#ifdef __cplusplus -#ifndef LODEPNG_NO_COMPILE_CPP -#define LODEPNG_COMPILE_CPP -#endif -#endif - -#ifdef LODEPNG_COMPILE_CPP -#include -#include -#endif /*LODEPNG_COMPILE_CPP*/ - -#ifdef LODEPNG_COMPILE_PNG -/*The PNG color types (also used for raw image).*/ -typedef enum LodePNGColorType { - LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/ - LCT_RGB = 2, /*RGB: 8,16 bit*/ - LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/ - LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/ - LCT_RGBA = 6, /*RGB with alpha: 8,16 bit*/ - /*LCT_MAX_OCTET_VALUE lets the compiler allow this enum to represent any invalid - byte value from 0 to 255 that could be present in an invalid PNG file header. Do - not use, compare with or set the name LCT_MAX_OCTET_VALUE, instead either use - the valid color type names above, or numeric values like 1 or 7 when checking for - particular disallowed color type byte values, or cast to integer to print it.*/ - LCT_MAX_OCTET_VALUE = 255 -} LodePNGColorType; - -#ifdef LODEPNG_COMPILE_DECODER -/* -Converts PNG data in memory to raw pixel data. -out: Output parameter. Pointer to buffer that will contain the raw pixel data. - After decoding, its size is w * h * (bytes per pixel) bytes larger than - initially. Bytes per pixel depends on colortype and bitdepth. - Must be freed after usage with free(*out). - Note: for 16-bit per channel colors, uses big endian format like PNG does. -w: Output parameter. Pointer to width of pixel data. -h: Output parameter. Pointer to height of pixel data. -in: Memory buffer with the PNG file. -insize: size of the in buffer. -colortype: the desired color type for the raw output image. See explanation on PNG color types. -bitdepth: the desired bit depth for the raw output image. See explanation on PNG color types. -Return value: LodePNG error code (0 means no error). -*/ -unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, - const unsigned char* in, size_t insize, - LodePNGColorType colortype, unsigned bitdepth); - -/*Same as lodepng_decode_memory, but always decodes to 32-bit RGBA raw image*/ -unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, - const unsigned char* in, size_t insize); - -/*Same as lodepng_decode_memory, but always decodes to 24-bit RGB raw image*/ -unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, - const unsigned char* in, size_t insize); - -#ifdef LODEPNG_COMPILE_DISK -/* -Load PNG from disk, from file with given name. -Same as the other decode functions, but instead takes a filename as input. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory.*/ -unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, - const char* filename, - LodePNGColorType colortype, unsigned bitdepth); - -/*Same as lodepng_decode_file, but always decodes to 32-bit RGBA raw image. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory.*/ -unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, - const char* filename); - -/*Same as lodepng_decode_file, but always decodes to 24-bit RGB raw image. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory.*/ -unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, - const char* filename); -#endif /*LODEPNG_COMPILE_DISK*/ -#endif /*LODEPNG_COMPILE_DECODER*/ - - -#ifdef LODEPNG_COMPILE_ENCODER -/* -Converts raw pixel data into a PNG image in memory. The colortype and bitdepth - of the output PNG image cannot be chosen, they are automatically determined - by the colortype, bitdepth and content of the input pixel data. - Note: for 16-bit per channel colors, needs big endian format like PNG does. -out: Output parameter. Pointer to buffer that will contain the PNG image data. - Must be freed after usage with free(*out). -outsize: Output parameter. Pointer to the size in bytes of the out buffer. -image: The raw pixel data to encode. The size of this buffer should be - w * h * (bytes per pixel), bytes per pixel depends on colortype and bitdepth. -w: width of the raw pixel data in pixels. -h: height of the raw pixel data in pixels. -colortype: the color type of the raw input image. See explanation on PNG color types. -bitdepth: the bit depth of the raw input image. See explanation on PNG color types. -Return value: LodePNG error code (0 means no error). -*/ -unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, - const unsigned char* image, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth); - -/*Same as lodepng_encode_memory, but always encodes from 32-bit RGBA raw image.*/ -unsigned lodepng_encode32(unsigned char** out, size_t* outsize, - const unsigned char* image, unsigned w, unsigned h); - -/*Same as lodepng_encode_memory, but always encodes from 24-bit RGB raw image.*/ -unsigned lodepng_encode24(unsigned char** out, size_t* outsize, - const unsigned char* image, unsigned w, unsigned h); - -#ifdef LODEPNG_COMPILE_DISK -/* -Converts raw pixel data into a PNG file on disk. -Same as the other encode functions, but instead takes a filename as output. - -NOTE: This overwrites existing files without warning! - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and encode in-memory.*/ -unsigned lodepng_encode_file(const char* filename, - const unsigned char* image, unsigned w, unsigned h, - LodePNGColorType colortype, unsigned bitdepth); - -/*Same as lodepng_encode_file, but always encodes from 32-bit RGBA raw image. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and encode in-memory.*/ -unsigned lodepng_encode32_file(const char* filename, - const unsigned char* image, unsigned w, unsigned h); - -/*Same as lodepng_encode_file, but always encodes from 24-bit RGB raw image. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and encode in-memory.*/ -unsigned lodepng_encode24_file(const char* filename, - const unsigned char* image, unsigned w, unsigned h); -#endif /*LODEPNG_COMPILE_DISK*/ -#endif /*LODEPNG_COMPILE_ENCODER*/ - - -#ifdef LODEPNG_COMPILE_CPP -namespace lodepng { -#ifdef LODEPNG_COMPILE_DECODER -/*Same as lodepng_decode_memory, but decodes to an std::vector. The colortype -is the format to output the pixels to. Default is RGBA 8-bit per channel.*/ -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - const unsigned char* in, size_t insize, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - const std::vector& in, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -#ifdef LODEPNG_COMPILE_DISK -/* -Converts PNG file from disk to raw pixel data in memory. -Same as the other decode functions, but instead takes a filename as input. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory. -*/ -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - const std::string& filename, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -#endif /* LODEPNG_COMPILE_DISK */ -#endif /* LODEPNG_COMPILE_DECODER */ - -#ifdef LODEPNG_COMPILE_ENCODER -/*Same as lodepng_encode_memory, but encodes to an std::vector. colortype -is that of the raw input data. The output PNG color type will be auto chosen.*/ -unsigned encode(std::vector& out, - const unsigned char* in, unsigned w, unsigned h, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -unsigned encode(std::vector& out, - const std::vector& in, unsigned w, unsigned h, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -#ifdef LODEPNG_COMPILE_DISK -/* -Converts 32-bit RGBA raw pixel data into a PNG file on disk. -Same as the other encode functions, but instead takes a filename as output. - -NOTE: This overwrites existing files without warning! - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory. -*/ -unsigned encode(const std::string& filename, - const unsigned char* in, unsigned w, unsigned h, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -unsigned encode(const std::string& filename, - const std::vector& in, unsigned w, unsigned h, - LodePNGColorType colortype = LCT_RGBA, unsigned bitdepth = 8); -#endif /* LODEPNG_COMPILE_DISK */ -#endif /* LODEPNG_COMPILE_ENCODER */ -} /* namespace lodepng */ -#endif /*LODEPNG_COMPILE_CPP*/ -#endif /*LODEPNG_COMPILE_PNG*/ - -#ifdef LODEPNG_COMPILE_ERROR_TEXT -/*Returns an English description of the numerical error code.*/ -const char* lodepng_error_text(unsigned code); -#endif /*LODEPNG_COMPILE_ERROR_TEXT*/ - -#ifdef LODEPNG_COMPILE_DECODER -/*Settings for zlib decompression*/ -typedef struct LodePNGDecompressSettings LodePNGDecompressSettings; -struct LodePNGDecompressSettings { - /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */ - unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/ - unsigned ignore_nlen; /*ignore complement of len checksum in uncompressed blocks*/ - - /*Maximum decompressed size, beyond this the decoder may (and is encouraged to) stop decoding, - return an error, output a data size > max_output_size and all the data up to that point. This is - not hard limit nor a guarantee, but can prevent excessive memory usage. This setting is - ignored by the PNG decoder, but is used by the deflate/zlib decoder and can be used by custom ones. - Set to 0 to impose no limit (the default).*/ - size_t max_output_size; - - /*use custom zlib decoder instead of built in one (default: null). - Should return 0 if success, any non-0 if error (numeric value not exposed).*/ - unsigned (*custom_zlib)(unsigned char**, size_t*, - const unsigned char*, size_t, - const LodePNGDecompressSettings*); - /*use custom deflate decoder instead of built in one (default: null) - if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate). - Should return 0 if success, any non-0 if error (numeric value not exposed).*/ - unsigned (*custom_inflate)(unsigned char**, size_t*, - const unsigned char*, size_t, - const LodePNGDecompressSettings*); - - const void* custom_context; /*optional custom settings for custom functions*/ -}; - -extern const LodePNGDecompressSettings lodepng_default_decompress_settings; -void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings); -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER -/* -Settings for zlib compression. Tweaking these settings tweaks the balance -between speed and compression ratio. -*/ -typedef struct LodePNGCompressSettings LodePNGCompressSettings; -struct LodePNGCompressSettings /*deflate = compress*/ { - /*LZ77 related settings*/ - unsigned btype; /*the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.*/ - unsigned use_lz77; /*whether or not to use LZ77. Should be 1 for proper compression.*/ - unsigned windowsize; /*must be a power of two <= 32768. higher compresses more but is slower. Default value: 2048.*/ - unsigned minmatch; /*minimum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0*/ - unsigned nicematch; /*stop searching if >= this length found. Set to 258 for best compression. Default: 128*/ - unsigned lazymatching; /*use lazy matching: better compression but a bit slower. Default: true*/ - - /*use custom zlib encoder instead of built in one (default: null)*/ - unsigned (*custom_zlib)(unsigned char**, size_t*, - const unsigned char*, size_t, - const LodePNGCompressSettings*); - /*use custom deflate encoder instead of built in one (default: null) - if custom_zlib is used, custom_deflate is ignored since only the built in - zlib function will call custom_deflate*/ - unsigned (*custom_deflate)(unsigned char**, size_t*, - const unsigned char*, size_t, - const LodePNGCompressSettings*); - - const void* custom_context; /*optional custom settings for custom functions*/ -}; - -extern const LodePNGCompressSettings lodepng_default_compress_settings; -void lodepng_compress_settings_init(LodePNGCompressSettings* settings); -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#ifdef LODEPNG_COMPILE_PNG -/* -Color mode of an image. Contains all information required to decode the pixel -bits to RGBA colors. This information is the same as used in the PNG file -format, and is used both for PNG and raw image data in LodePNG. -*/ -typedef struct LodePNGColorMode { - /*header (IHDR)*/ - LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/ - unsigned bitdepth; /*bits per sample, see PNG standard or documentation further in this header file*/ - - /* - palette (PLTE and tRNS) - - Dynamically allocated with the colors of the palette, including alpha. - This field may not be allocated directly, use lodepng_color_mode_init first, - then lodepng_palette_add per color to correctly initialize it (to ensure size - of exactly 1024 bytes). - - The alpha channels must be set as well, set them to 255 for opaque images. - - When decoding, by default you can ignore this palette, since LodePNG already - fills the palette colors in the pixels of the raw RGBA output. - - The palette is only supported for color type 3. - */ - unsigned char* palette; /*palette in RGBARGBA... order. Must be either 0, or when allocated must have 1024 bytes*/ - size_t palettesize; /*palette size in number of colors (amount of used bytes is 4 * palettesize)*/ - - /* - transparent color key (tRNS) - - This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit. - For grayscale PNGs, r, g and b will all 3 be set to the same. - - When decoding, by default you can ignore this information, since LodePNG sets - pixels with this key to transparent already in the raw RGBA output. - - The color key is only supported for color types 0 and 2. - */ - unsigned key_defined; /*is a transparent color key given? 0 = false, 1 = true*/ - unsigned key_r; /*red/grayscale component of color key*/ - unsigned key_g; /*green component of color key*/ - unsigned key_b; /*blue component of color key*/ -} LodePNGColorMode; - -/*init, cleanup and copy functions to use with this struct*/ -void lodepng_color_mode_init(LodePNGColorMode* info); -void lodepng_color_mode_cleanup(LodePNGColorMode* info); -/*return value is error code (0 means no error)*/ -unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source); -/* Makes a temporary LodePNGColorMode that does not need cleanup (no palette) */ -LodePNGColorMode lodepng_color_mode_make(LodePNGColorType colortype, unsigned bitdepth); - -void lodepng_palette_clear(LodePNGColorMode* info); -/*add 1 color to the palette*/ -unsigned lodepng_palette_add(LodePNGColorMode* info, - unsigned char r, unsigned char g, unsigned char b, unsigned char a); - -/*get the total amount of bits per pixel, based on colortype and bitdepth in the struct*/ -unsigned lodepng_get_bpp(const LodePNGColorMode* info); -/*get the amount of color channels used, based on colortype in the struct. -If a palette is used, it counts as 1 channel.*/ -unsigned lodepng_get_channels(const LodePNGColorMode* info); -/*is it a grayscale type? (only colortype 0 or 4)*/ -unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info); -/*has it got an alpha channel? (only colortype 2 or 6)*/ -unsigned lodepng_is_alpha_type(const LodePNGColorMode* info); -/*has it got a palette? (only colortype 3)*/ -unsigned lodepng_is_palette_type(const LodePNGColorMode* info); -/*only returns true if there is a palette and there is a value in the palette with alpha < 255. -Loops through the palette to check this.*/ -unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info); -/* -Check if the given color info indicates the possibility of having non-opaque pixels in the PNG image. -Returns true if the image can have translucent or invisible pixels (it still be opaque if it doesn't use such pixels). -Returns false if the image can only have opaque pixels. -In detail, it returns true only if it's a color type with alpha, or has a palette with non-opaque values, -or if "key_defined" is true. -*/ -unsigned lodepng_can_have_alpha(const LodePNGColorMode* info); -/*Returns the byte size of a raw image buffer with given width, height and color mode*/ -size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color); - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS -/*The information of a Time chunk in PNG.*/ -typedef struct LodePNGTime { - unsigned year; /*2 bytes used (0-65535)*/ - unsigned month; /*1-12*/ - unsigned day; /*1-31*/ - unsigned hour; /*0-23*/ - unsigned minute; /*0-59*/ - unsigned second; /*0-60 (to allow for leap seconds)*/ -} LodePNGTime; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -/*Information about the PNG image, except pixels, width and height.*/ -typedef struct LodePNGInfo { - /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/ - unsigned compression_method;/*compression method of the original file. Always 0.*/ - unsigned filter_method; /*filter method of the original file*/ - unsigned interlace_method; /*interlace method of the original file: 0=none, 1=Adam7*/ - LodePNGColorMode color; /*color type and bits, palette and transparency of the PNG file*/ - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /* - Suggested background color chunk (bKGD) - - This uses the same color mode and bit depth as the PNG (except no alpha channel), - with values truncated to the bit depth in the unsigned integer. - - For grayscale and palette PNGs, the value is stored in background_r. The values - in background_g and background_b are then unused. - - So when decoding, you may get these in a different color mode than the one you requested - for the raw pixels. - - When encoding with auto_convert, you must use the color model defined in info_png.color for - these values. The encoder normally ignores info_png.color when auto_convert is on, but will - use it to interpret these values (and convert copies of them to its chosen color model). - - When encoding, avoid setting this to an expensive color, such as a non-gray value - when the image is gray, or the compression will be worse since it will be forced to - write the PNG with a more expensive color mode (when auto_convert is on). - - The decoder does not use this background color to edit the color of pixels. This is a - completely optional metadata feature. - */ - unsigned background_defined; /*is a suggested background color given?*/ - unsigned background_r; /*red/gray/palette component of suggested background color*/ - unsigned background_g; /*green component of suggested background color*/ - unsigned background_b; /*blue component of suggested background color*/ - - /* - Non-international text chunks (tEXt and zTXt) - - The char** arrays each contain num strings. The actual messages are in - text_strings, while text_keys are keywords that give a short description what - the actual text represents, e.g. Title, Author, Description, or anything else. - - All the string fields below including strings, keys, names and language tags are null terminated. - The PNG specification uses null characters for the keys, names and tags, and forbids null - characters to appear in the main text which is why we can use null termination everywhere here. - - A keyword is minimum 1 character and maximum 79 characters long (plus the - additional null terminator). It's discouraged to use a single line length - longer than 79 characters for texts. - - Don't allocate these text buffers yourself. Use the init/cleanup functions - correctly and use lodepng_add_text and lodepng_clear_text. - - Standard text chunk keywords and strings are encoded using Latin-1. - */ - size_t text_num; /*the amount of texts in these char** buffers (there may be more texts in itext)*/ - char** text_keys; /*the keyword of a text chunk (e.g. "Comment")*/ - char** text_strings; /*the actual text*/ - - /* - International text chunks (iTXt) - Similar to the non-international text chunks, but with additional strings - "langtags" and "transkeys", and the following text encodings are used: - keys: Latin-1, langtags: ASCII, transkeys and strings: UTF-8. - keys must be 1-79 characters (plus the additional null terminator), the other - strings are any length. - */ - size_t itext_num; /*the amount of international texts in this PNG*/ - char** itext_keys; /*the English keyword of the text chunk (e.g. "Comment")*/ - char** itext_langtags; /*language tag for this text's language, ISO/IEC 646 string, e.g. ISO 639 language tag*/ - char** itext_transkeys; /*keyword translated to the international language - UTF-8 string*/ - char** itext_strings; /*the actual international text - UTF-8 string*/ - - /*time chunk (tIME)*/ - unsigned time_defined; /*set to 1 to make the encoder generate a tIME chunk*/ - LodePNGTime time; - - /*phys chunk (pHYs)*/ - unsigned phys_defined; /*if 0, there is no pHYs chunk and the values below are undefined, if 1 else there is one*/ - unsigned phys_x; /*pixels per unit in x direction*/ - unsigned phys_y; /*pixels per unit in y direction*/ - unsigned phys_unit; /*may be 0 (unknown unit) or 1 (metre)*/ - - /* - Color profile related chunks: gAMA, cHRM, sRGB, iCPP - - LodePNG does not apply any color conversions on pixels in the encoder or decoder and does not interpret these color - profile values. It merely passes on the information. If you wish to use color profiles and convert colors, please - use these values with a color management library. - - See the PNG, ICC and sRGB specifications for more information about the meaning of these values. - */ - - /* gAMA chunk: optional, overridden by sRGB or iCCP if those are present. */ - unsigned gama_defined; /* Whether a gAMA chunk is present (0 = not present, 1 = present). */ - unsigned gama_gamma; /* Gamma exponent times 100000 */ - - /* cHRM chunk: optional, overridden by sRGB or iCCP if those are present. */ - unsigned chrm_defined; /* Whether a cHRM chunk is present (0 = not present, 1 = present). */ - unsigned chrm_white_x; /* White Point x times 100000 */ - unsigned chrm_white_y; /* White Point y times 100000 */ - unsigned chrm_red_x; /* Red x times 100000 */ - unsigned chrm_red_y; /* Red y times 100000 */ - unsigned chrm_green_x; /* Green x times 100000 */ - unsigned chrm_green_y; /* Green y times 100000 */ - unsigned chrm_blue_x; /* Blue x times 100000 */ - unsigned chrm_blue_y; /* Blue y times 100000 */ - - /* - sRGB chunk: optional. May not appear at the same time as iCCP. - If gAMA is also present gAMA must contain value 45455. - If cHRM is also present cHRM must contain respectively 31270,32900,64000,33000,30000,60000,15000,6000. - */ - unsigned srgb_defined; /* Whether an sRGB chunk is present (0 = not present, 1 = present). */ - unsigned srgb_intent; /* Rendering intent: 0=perceptual, 1=rel. colorimetric, 2=saturation, 3=abs. colorimetric */ - - /* - iCCP chunk: optional. May not appear at the same time as sRGB. - - LodePNG does not parse or use the ICC profile (except its color space header field for an edge case), a - separate library to handle the ICC data (not included in LodePNG) format is needed to use it for color - management and conversions. - - For encoding, if iCCP is present, gAMA and cHRM are recommended to be added as well with values that match the ICC - profile as closely as possible, if you wish to do this you should provide the correct values for gAMA and cHRM and - enable their '_defined' flags since LodePNG will not automatically compute them from the ICC profile. - - For encoding, the ICC profile is required by the PNG specification to be an "RGB" profile for non-gray - PNG color types and a "GRAY" profile for gray PNG color types. If you disable auto_convert, you must ensure - the ICC profile type matches your requested color type, else the encoder gives an error. If auto_convert is - enabled (the default), and the ICC profile is not a good match for the pixel data, this will result in an encoder - error if the pixel data has non-gray pixels for a GRAY profile, or a silent less-optimal compression of the pixel - data if the pixels could be encoded as grayscale but the ICC profile is RGB. - - To avoid this do not set an ICC profile in the image unless there is a good reason for it, and when doing so - make sure you compute it carefully to avoid the above problems. - */ - unsigned iccp_defined; /* Whether an iCCP chunk is present (0 = not present, 1 = present). */ - char* iccp_name; /* Null terminated string with profile name, 1-79 bytes */ - /* - The ICC profile in iccp_profile_size bytes. - Don't allocate this buffer yourself. Use the init/cleanup functions - correctly and use lodepng_set_icc and lodepng_clear_icc. - */ - unsigned char* iccp_profile; - unsigned iccp_profile_size; /* The size of iccp_profile in bytes */ - - /* End of color profile related chunks */ - - - /* - unknown chunks: chunks not known by LodePNG, passed on byte for byte. - - There are 3 buffers, one for each position in the PNG where unknown chunks can appear. - Each buffer contains all unknown chunks for that position consecutively. - The 3 positions are: - 0: between IHDR and PLTE, 1: between PLTE and IDAT, 2: between IDAT and IEND. - - For encoding, do not store critical chunks or known chunks that are enabled with a "_defined" flag - above in here, since the encoder will blindly follow this and could then encode an invalid PNG file - (such as one with two IHDR chunks or the disallowed combination of sRGB with iCCP). But do use - this if you wish to store an ancillary chunk that is not supported by LodePNG (such as sPLT or hIST), - or any non-standard PNG chunk. - - Do not allocate or traverse this data yourself. Use the chunk traversing functions declared - later, such as lodepng_chunk_next and lodepng_chunk_append, to read/write this struct. - */ - unsigned char* unknown_chunks_data[3]; - size_t unknown_chunks_size[3]; /*size in bytes of the unknown chunks, given for protection*/ -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} LodePNGInfo; - -/*init, cleanup and copy functions to use with this struct*/ -void lodepng_info_init(LodePNGInfo* info); -void lodepng_info_cleanup(LodePNGInfo* info); -/*return value is error code (0 means no error)*/ -unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source); - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS -unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str); /*push back both texts at once*/ -void lodepng_clear_text(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/ - -unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag, - const char* transkey, const char* str); /*push back the 4 texts of 1 chunk at once*/ -void lodepng_clear_itext(LodePNGInfo* info); /*use this to clear the itexts again after you filled them in*/ - -/*replaces if exists*/ -unsigned lodepng_set_icc(LodePNGInfo* info, const char* name, const unsigned char* profile, unsigned profile_size); -void lodepng_clear_icc(LodePNGInfo* info); /*use this to clear the texts again after you filled them in*/ -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ - -/* -Converts raw buffer from one color type to another color type, based on -LodePNGColorMode structs to describe the input and output color type. -See the reference manual at the end of this header file to see which color conversions are supported. -return value = LodePNG error code (0 if all went ok, an error if the conversion isn't supported) -The out buffer must have size (w * h * bpp + 7) / 8, where bpp is the bits per pixel -of the output color type (lodepng_get_bpp). -For < 8 bpp images, there should not be padding bits at the end of scanlines. -For 16-bit per channel colors, uses big endian format like PNG does. -Return value is LodePNG error code -*/ -unsigned lodepng_convert(unsigned char* out, const unsigned char* in, - const LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in, - unsigned w, unsigned h); - -#ifdef LODEPNG_COMPILE_DECODER -/* -Settings for the decoder. This contains settings for the PNG and the Zlib -decoder, but not the Info settings from the Info structs. -*/ -typedef struct LodePNGDecoderSettings { - LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/ - - /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */ - unsigned ignore_crc; /*ignore CRC checksums*/ - unsigned ignore_critical; /*ignore unknown critical chunks*/ - unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/ - /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable - errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some - strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters - in string keys, etc... */ - - unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/ - -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - unsigned read_text_chunks; /*if false but remember_unknown_chunks is true, they're stored in the unknown chunks*/ - - /*store all bytes from unknown chunks in the LodePNGInfo (off by default, useful for a png editor)*/ - unsigned remember_unknown_chunks; - - /* maximum size for decompressed text chunks. If a text chunk's text is larger than this, an error is returned, - unless reading text chunks is disabled or this limit is set higher or disabled. Set to 0 to allow any size. - By default it is a value that prevents unreasonably large strings from hogging memory. */ - size_t max_text_size; - - /* maximum size for compressed ICC chunks. If the ICC profile is larger than this, an error will be returned. Set to - 0 to allow any size. By default this is a value that prevents ICC profiles that would be much larger than any - legitimate profile could be to hog memory. */ - size_t max_icc_size; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} LodePNGDecoderSettings; - -void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings); -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER -/*automatically use color type with less bits per pixel if losslessly possible. Default: AUTO*/ -typedef enum LodePNGFilterStrategy { - /*every filter at zero*/ - LFS_ZERO = 0, - /*every filter at 1, 2, 3 or 4 (paeth), unlike LFS_ZERO not a good choice, but for testing*/ - LFS_ONE = 1, - LFS_TWO = 2, - LFS_THREE = 3, - LFS_FOUR = 4, - /*Use filter that gives minimum sum, as described in the official PNG filter heuristic.*/ - LFS_MINSUM, - /*Use the filter type that gives smallest Shannon entropy for this scanline. Depending - on the image, this is better or worse than minsum.*/ - LFS_ENTROPY, - /* - Brute-force-search PNG filters by compressing each filter for each scanline. - Experimental, very slow, and only rarely gives better compression than MINSUM. - */ - LFS_BRUTE_FORCE, - /*use predefined_filters buffer: you specify the filter type for each scanline*/ - LFS_PREDEFINED -} LodePNGFilterStrategy; - -/*Gives characteristics about the integer RGBA colors of the image (count, alpha channel usage, bit depth, ...), -which helps decide which color model to use for encoding. -Used internally by default if "auto_convert" is enabled. Public because it's useful for custom algorithms.*/ -typedef struct LodePNGColorStats { - unsigned colored; /*not grayscale*/ - unsigned key; /*image is not opaque and color key is possible instead of full alpha*/ - unsigned short key_r; /*key values, always as 16-bit, in 8-bit case the byte is duplicated, e.g. 65535 means 255*/ - unsigned short key_g; - unsigned short key_b; - unsigned alpha; /*image is not opaque and alpha channel or alpha palette required*/ - unsigned numcolors; /*amount of colors, up to 257. Not valid if bits == 16 or allow_palette is disabled.*/ - unsigned char palette[1024]; /*Remembers up to the first 256 RGBA colors, in no particular order, only valid when numcolors is valid*/ - unsigned bits; /*bits per channel (not for palette). 1,2 or 4 for grayscale only. 16 if 16-bit per channel required.*/ - size_t numpixels; - - /*user settings for computing/using the stats*/ - unsigned allow_palette; /*default 1. if 0, disallow choosing palette colortype in auto_choose_color, and don't count numcolors*/ - unsigned allow_greyscale; /*default 1. if 0, choose RGB or RGBA even if the image only has gray colors*/ -} LodePNGColorStats; - -void lodepng_color_stats_init(LodePNGColorStats* stats); - -/*Get a LodePNGColorStats of the image. The stats must already have been inited. -Returns error code (e.g. alloc fail) or 0 if ok.*/ -unsigned lodepng_compute_color_stats(LodePNGColorStats* stats, - const unsigned char* image, unsigned w, unsigned h, - const LodePNGColorMode* mode_in); - -/*Settings for the encoder.*/ -typedef struct LodePNGEncoderSettings { - LodePNGCompressSettings zlibsettings; /*settings for the zlib encoder, such as window size, ...*/ - - unsigned auto_convert; /*automatically choose output PNG color type. Default: true*/ - - /*If true, follows the official PNG heuristic: if the PNG uses a palette or lower than - 8 bit depth, set all filters to zero. Otherwise use the filter_strategy. Note that to - completely follow the official PNG heuristic, filter_palette_zero must be true and - filter_strategy must be LFS_MINSUM*/ - unsigned filter_palette_zero; - /*Which filter strategy to use when not using zeroes due to filter_palette_zero. - Set filter_palette_zero to 0 to ensure always using your chosen strategy. Default: LFS_MINSUM*/ - LodePNGFilterStrategy filter_strategy; - /*used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with - the same length as the amount of scanlines in the image, and each value must <= 5. You - have to cleanup this buffer, LodePNG will never free it. Don't forget that filter_palette_zero - must be set to 0 to ensure this is also used on palette or low bitdepth images.*/ - const unsigned char* predefined_filters; - - /*force creating a PLTE chunk if colortype is 2 or 6 (= a suggested palette). - If colortype is 3, PLTE is _always_ created.*/ - unsigned force_palette; -#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS - /*add LodePNG identifier and version as a text chunk, for debugging*/ - unsigned add_id; - /*encode text chunks as zTXt chunks instead of tEXt chunks, and use compression in iTXt chunks*/ - unsigned text_compression; -#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/ -} LodePNGEncoderSettings; - -void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings); -#endif /*LODEPNG_COMPILE_ENCODER*/ - - -#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) -/*The settings, state and information for extended encoding and decoding.*/ -typedef struct LodePNGState { -#ifdef LODEPNG_COMPILE_DECODER - LodePNGDecoderSettings decoder; /*the decoding settings*/ -#endif /*LODEPNG_COMPILE_DECODER*/ -#ifdef LODEPNG_COMPILE_ENCODER - LodePNGEncoderSettings encoder; /*the encoding settings*/ -#endif /*LODEPNG_COMPILE_ENCODER*/ - LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/ - LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/ - unsigned error; -} LodePNGState; - -/*init, cleanup and copy functions to use with this struct*/ -void lodepng_state_init(LodePNGState* state); -void lodepng_state_cleanup(LodePNGState* state); -void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source); -#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */ - -#ifdef LODEPNG_COMPILE_DECODER -/* -Same as lodepng_decode_memory, but uses a LodePNGState to allow custom settings and -getting much more information about the PNG image and color mode. -*/ -unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, - LodePNGState* state, - const unsigned char* in, size_t insize); - -/* -Read the PNG header, but not the actual data. This returns only the information -that is in the IHDR chunk of the PNG, such as width, height and color type. The -information is placed in the info_png field of the LodePNGState. -*/ -unsigned lodepng_inspect(unsigned* w, unsigned* h, - LodePNGState* state, - const unsigned char* in, size_t insize); -#endif /*LODEPNG_COMPILE_DECODER*/ - -/* -Reads one metadata chunk (other than IHDR) of the PNG file and outputs what it -read in the state. Returns error code on failure. -Use lodepng_inspect first with a new state, then e.g. lodepng_chunk_find_const -to find the desired chunk type, and if non null use lodepng_inspect_chunk (with -chunk_pointer - start_of_file as pos). -Supports most metadata chunks from the PNG standard (gAMA, bKGD, tEXt, ...). -Ignores unsupported, unknown, non-metadata or IHDR chunks (without error). -Requirements: &in[pos] must point to start of a chunk, must use regular -lodepng_inspect first since format of most other chunks depends on IHDR, and if -there is a PLTE chunk, that one must be inspected before tRNS or bKGD. -*/ -unsigned lodepng_inspect_chunk(LodePNGState* state, size_t pos, - const unsigned char* in, size_t insize); - -#ifdef LODEPNG_COMPILE_ENCODER -/*This function allocates the out buffer with standard malloc and stores the size in *outsize.*/ -unsigned lodepng_encode(unsigned char** out, size_t* outsize, - const unsigned char* image, unsigned w, unsigned h, - LodePNGState* state); -#endif /*LODEPNG_COMPILE_ENCODER*/ - -/* -The lodepng_chunk functions are normally not needed, except to traverse the -unknown chunks stored in the LodePNGInfo struct, or add new ones to it. -It also allows traversing the chunks of an encoded PNG file yourself. - -The chunk pointer always points to the beginning of the chunk itself, that is -the first byte of the 4 length bytes. - -In the PNG file format, chunks have the following format: --4 bytes length: length of the data of the chunk in bytes (chunk itself is 12 bytes longer) --4 bytes chunk type (ASCII a-z,A-Z only, see below) --length bytes of data (may be 0 bytes if length was 0) --4 bytes of CRC, computed on chunk name + data - -The first chunk starts at the 8th byte of the PNG file, the entire rest of the file -exists out of concatenated chunks with the above format. - -PNG standard chunk ASCII naming conventions: --First byte: uppercase = critical, lowercase = ancillary --Second byte: uppercase = public, lowercase = private --Third byte: must be uppercase --Fourth byte: uppercase = unsafe to copy, lowercase = safe to copy -*/ - -/* -Gets the length of the data of the chunk. Total chunk length has 12 bytes more. -There must be at least 4 bytes to read from. If the result value is too large, -it may be corrupt data. -*/ -unsigned lodepng_chunk_length(const unsigned char* chunk); - -/*puts the 4-byte type in null terminated string*/ -void lodepng_chunk_type(char type[5], const unsigned char* chunk); - -/*check if the type is the given type*/ -unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type); - -/*0: it's one of the critical chunk types, 1: it's an ancillary chunk (see PNG standard)*/ -unsigned char lodepng_chunk_ancillary(const unsigned char* chunk); - -/*0: public, 1: private (see PNG standard)*/ -unsigned char lodepng_chunk_private(const unsigned char* chunk); - -/*0: the chunk is unsafe to copy, 1: the chunk is safe to copy (see PNG standard)*/ -unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk); - -/*get pointer to the data of the chunk, where the input points to the header of the chunk*/ -unsigned char* lodepng_chunk_data(unsigned char* chunk); -const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk); - -/*returns 0 if the crc is correct, 1 if it's incorrect (0 for OK as usual!)*/ -unsigned lodepng_chunk_check_crc(const unsigned char* chunk); - -/*generates the correct CRC from the data and puts it in the last 4 bytes of the chunk*/ -void lodepng_chunk_generate_crc(unsigned char* chunk); - -/* -Iterate to next chunks, allows iterating through all chunks of the PNG file. -Input must be at the beginning of a chunk (result of a previous lodepng_chunk_next call, -or the 8th byte of a PNG file which always has the first chunk), or alternatively may -point to the first byte of the PNG file (which is not a chunk but the magic header, the -function will then skip over it and return the first real chunk). -Will output pointer to the start of the next chunk, or at or beyond end of the file if there -is no more chunk after this or possibly if the chunk is corrupt. -Start this process at the 8th byte of the PNG file. -In a non-corrupt PNG file, the last chunk should have name "IEND". -*/ -unsigned char* lodepng_chunk_next(unsigned char* chunk, unsigned char* end); -const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk, const unsigned char* end); - -/*Finds the first chunk with the given type in the range [chunk, end), or returns NULL if not found.*/ -unsigned char* lodepng_chunk_find(unsigned char* chunk, unsigned char* end, const char type[5]); -const unsigned char* lodepng_chunk_find_const(const unsigned char* chunk, const unsigned char* end, const char type[5]); - -/* -Appends chunk to the data in out. The given chunk should already have its chunk header. -The out variable and outsize are updated to reflect the new reallocated buffer. -Returns error code (0 if it went ok) -*/ -unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk); - -/* -Appends new chunk to out. The chunk to append is given by giving its length, type -and data separately. The type is a 4-letter string. -The out variable and outsize are updated to reflect the new reallocated buffer. -Returne error code (0 if it went ok) -*/ -unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, unsigned length, - const char* type, const unsigned char* data); - - -/*Calculate CRC32 of buffer*/ -unsigned lodepng_crc32(const unsigned char* buf, size_t len); -#endif /*LODEPNG_COMPILE_PNG*/ - - -#ifdef LODEPNG_COMPILE_ZLIB -/* -This zlib part can be used independently to zlib compress and decompress a -buffer. It cannot be used to create gzip files however, and it only supports the -part of zlib that is required for PNG, it does not support dictionaries. -*/ - -#ifdef LODEPNG_COMPILE_DECODER -/*Inflate a buffer. Inflate is the decompression step of deflate. Out buffer must be freed after use.*/ -unsigned lodepng_inflate(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings); - -/* -Decompresses Zlib data. Reallocates the out buffer and appends the data. The -data must be according to the zlib specification. -Either, *out must be NULL and *outsize must be 0, or, *out must be a valid -buffer and *outsize its size in bytes. out must be freed by user after usage. -*/ -unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGDecompressSettings* settings); -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER -/* -Compresses data with Zlib. Reallocates the out buffer and appends the data. -Zlib adds a small header and trailer around the deflate data. -The data is output in the format of the zlib specification. -Either, *out must be NULL and *outsize must be 0, or, *out must be a valid -buffer and *outsize its size in bytes. out must be freed by user after usage. -*/ -unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGCompressSettings* settings); - -/* -Find length-limited Huffman code for given frequencies. This function is in the -public interface only for tests, it's used internally by lodepng_deflate. -*/ -unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies, - size_t numcodes, unsigned maxbitlen); - -/*Compress a buffer with deflate. See RFC 1951. Out buffer must be freed after use.*/ -unsigned lodepng_deflate(unsigned char** out, size_t* outsize, - const unsigned char* in, size_t insize, - const LodePNGCompressSettings* settings); - -#endif /*LODEPNG_COMPILE_ENCODER*/ -#endif /*LODEPNG_COMPILE_ZLIB*/ - -#ifdef LODEPNG_COMPILE_DISK -/* -Load a file from disk into buffer. The function allocates the out buffer, and -after usage you should free it. -out: output parameter, contains pointer to loaded buffer. -outsize: output parameter, size of the allocated out buffer -filename: the path to the file to load -return value: error code (0 means ok) - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory. -*/ -unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename); - -/* -Save a file from buffer to disk. Warning, if it exists, this function overwrites -the file without warning! -buffer: the buffer to write -buffersize: size of the buffer to write -filename: the path to the file to save to -return value: error code (0 means ok) - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and encode in-memory -*/ -unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename); -#endif /*LODEPNG_COMPILE_DISK*/ - -#ifdef LODEPNG_COMPILE_CPP -/* The LodePNG C++ wrapper uses std::vectors instead of manually allocated memory buffers. */ -namespace lodepng { -#ifdef LODEPNG_COMPILE_PNG -class State : public LodePNGState { - public: - State(); - State(const State& other); - ~State(); - State& operator=(const State& other); -}; - -#ifdef LODEPNG_COMPILE_DECODER -/* Same as other lodepng::decode, but using a State for more settings and information. */ -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - State& state, - const unsigned char* in, size_t insize); -unsigned decode(std::vector& out, unsigned& w, unsigned& h, - State& state, - const std::vector& in); -#endif /*LODEPNG_COMPILE_DECODER*/ - -#ifdef LODEPNG_COMPILE_ENCODER -/* Same as other lodepng::encode, but using a State for more settings and information. */ -unsigned encode(std::vector& out, - const unsigned char* in, unsigned w, unsigned h, - State& state); -unsigned encode(std::vector& out, - const std::vector& in, unsigned w, unsigned h, - State& state); -#endif /*LODEPNG_COMPILE_ENCODER*/ - -#ifdef LODEPNG_COMPILE_DISK -/* -Load a file from disk into an std::vector. -return value: error code (0 means ok) - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and decode in-memory -*/ -unsigned load_file(std::vector& buffer, const std::string& filename); - -/* -Save the binary data in an std::vector to a file on disk. The file is overwritten -without warning. - -NOTE: Wide-character filenames are not supported, you can use an external method -to handle such files and encode in-memory -*/ -unsigned save_file(const std::vector& buffer, const std::string& filename); -#endif /* LODEPNG_COMPILE_DISK */ -#endif /* LODEPNG_COMPILE_PNG */ - -#ifdef LODEPNG_COMPILE_ZLIB -#ifdef LODEPNG_COMPILE_DECODER -/* Zlib-decompress an unsigned char buffer */ -unsigned decompress(std::vector& out, const unsigned char* in, size_t insize, - const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings); - -/* Zlib-decompress an std::vector */ -unsigned decompress(std::vector& out, const std::vector& in, - const LodePNGDecompressSettings& settings = lodepng_default_decompress_settings); -#endif /* LODEPNG_COMPILE_DECODER */ - -#ifdef LODEPNG_COMPILE_ENCODER -/* Zlib-compress an unsigned char buffer */ -unsigned compress(std::vector& out, const unsigned char* in, size_t insize, - const LodePNGCompressSettings& settings = lodepng_default_compress_settings); - -/* Zlib-compress an std::vector */ -unsigned compress(std::vector& out, const std::vector& in, - const LodePNGCompressSettings& settings = lodepng_default_compress_settings); -#endif /* LODEPNG_COMPILE_ENCODER */ -#endif /* LODEPNG_COMPILE_ZLIB */ -} /* namespace lodepng */ -#endif /*LODEPNG_COMPILE_CPP*/ - -/* -TODO: -[.] test if there are no memory leaks or security exploits - done a lot but needs to be checked often -[.] check compatibility with various compilers - done but needs to be redone for every newer version -[X] converting color to 16-bit per channel types -[X] support color profile chunk types (but never let them touch RGB values by default) -[ ] support all public PNG chunk types (almost done except sBIT, sPLT and hIST) -[ ] make sure encoder generates no chunks with size > (2^31)-1 -[ ] partial decoding (stream processing) -[X] let the "isFullyOpaque" function check color keys and transparent palettes too -[X] better name for the variables "codes", "codesD", "codelengthcodes", "clcl" and "lldl" -[ ] allow treating some errors like warnings, when image is recoverable (e.g. 69, 57, 58) -[ ] make warnings like: oob palette, checksum fail, data after iend, wrong/unknown crit chunk, no null terminator in text, ... -[ ] error messages with line numbers (and version) -[ ] errors in state instead of as return code? -[ ] new errors/warnings like suspiciously big decompressed ztxt or iccp chunk -[ ] let the C++ wrapper catch exceptions coming from the standard library and return LodePNG error codes -[ ] allow user to provide custom color conversion functions, e.g. for premultiplied alpha, padding bits or not, ... -[ ] allow user to give data (void*) to custom allocator -[X] provide alternatives for C library functions not present on some platforms (memcpy, ...) -*/ - -#endif /*LODEPNG_H inclusion guard*/ - -/* -LodePNG Documentation ---------------------- - -0. table of contents --------------------- - - 1. about - 1.1. supported features - 1.2. features not supported - 2. C and C++ version - 3. security - 4. decoding - 5. encoding - 6. color conversions - 6.1. PNG color types - 6.2. color conversions - 6.3. padding bits - 6.4. A note about 16-bits per channel and endianness - 7. error values - 8. chunks and PNG editing - 9. compiler support - 10. examples - 10.1. decoder C++ example - 10.2. decoder C example - 11. state settings reference - 12. changes - 13. contact information - - -1. about --------- - -PNG is a file format to store raster images losslessly with good compression, -supporting different color types and alpha channel. - -LodePNG is a PNG codec according to the Portable Network Graphics (PNG) -Specification (Second Edition) - W3C Recommendation 10 November 2003. - -The specifications used are: - -*) Portable Network Graphics (PNG) Specification (Second Edition): - http://www.w3.org/TR/2003/REC-PNG-20031110 -*) RFC 1950 ZLIB Compressed Data Format version 3.3: - http://www.gzip.org/zlib/rfc-zlib.html -*) RFC 1951 DEFLATE Compressed Data Format Specification ver 1.3: - http://www.gzip.org/zlib/rfc-deflate.html - -The most recent version of LodePNG can currently be found at -http://lodev.org/lodepng/ - -LodePNG works both in C (ISO C90) and C++, with a C++ wrapper that adds -extra functionality. - -LodePNG exists out of two files: --lodepng.h: the header file for both C and C++ --lodepng.c(pp): give it the name lodepng.c or lodepng.cpp (or .cc) depending on your usage - -If you want to start using LodePNG right away without reading this doc, get the -examples from the LodePNG website to see how to use it in code, or check the -smaller examples in chapter 13 here. - -LodePNG is simple but only supports the basic requirements. To achieve -simplicity, the following design choices were made: There are no dependencies -on any external library. There are functions to decode and encode a PNG with -a single function call, and extended versions of these functions taking a -LodePNGState struct allowing to specify or get more information. By default -the colors of the raw image are always RGB or RGBA, no matter what color type -the PNG file uses. To read and write files, there are simple functions to -convert the files to/from buffers in memory. - -This all makes LodePNG suitable for loading textures in games, demos and small -programs, ... It's less suitable for full fledged image editors, loading PNGs -over network (it requires all the image data to be available before decoding can -begin), life-critical systems, ... - -1.1. supported features ------------------------ - -The following features are supported by the decoder: - -*) decoding of PNGs with any color type, bit depth and interlace mode, to a 24- or 32-bit color raw image, - or the same color type as the PNG -*) encoding of PNGs, from any raw image to 24- or 32-bit color, or the same color type as the raw image -*) Adam7 interlace and deinterlace for any color type -*) loading the image from harddisk or decoding it from a buffer from other sources than harddisk -*) support for alpha channels, including RGBA color model, translucent palettes and color keying -*) zlib decompression (inflate) -*) zlib compression (deflate) -*) CRC32 and ADLER32 checksums -*) colorimetric color profile conversions: currently experimentally available in lodepng_util.cpp only, - plus alternatively ability to pass on chroma/gamma/ICC profile information to other color management system. -*) handling of unknown chunks, allowing making a PNG editor that stores custom and unknown chunks. -*) the following chunks are supported by both encoder and decoder: - IHDR: header information - PLTE: color palette - IDAT: pixel data - IEND: the final chunk - tRNS: transparency for palettized images - tEXt: textual information - zTXt: compressed textual information - iTXt: international textual information - bKGD: suggested background color - pHYs: physical dimensions - tIME: modification time - cHRM: RGB chromaticities - gAMA: RGB gamma correction - iCCP: ICC color profile - sRGB: rendering intent - -1.2. features not supported ---------------------------- - -The following features are _not_ supported: - -*) some features needed to make a conformant PNG-Editor might be still missing. -*) partial loading/stream processing. All data must be available and is processed in one call. -*) The following public chunks are not (yet) supported but treated as unknown chunks by LodePNG: - sBIT - hIST - sPLT - - -2. C and C++ version --------------------- - -The C version uses buffers allocated with alloc that you need to free() -yourself. You need to use init and cleanup functions for each struct whenever -using a struct from the C version to avoid exploits and memory leaks. - -The C++ version has extra functions with std::vectors in the interface and the -lodepng::State class which is a LodePNGState with constructor and destructor. - -These files work without modification for both C and C++ compilers because all -the additional C++ code is in "#ifdef __cplusplus" blocks that make C-compilers -ignore it, and the C code is made to compile both with strict ISO C90 and C++. - -To use the C++ version, you need to rename the source file to lodepng.cpp -(instead of lodepng.c), and compile it with a C++ compiler. - -To use the C version, you need to rename the source file to lodepng.c (instead -of lodepng.cpp), and compile it with a C compiler. - - -3. Security ------------ - -Even if carefully designed, it's always possible that LodePNG contains possible -exploits. If you discover one, please let me know, and it will be fixed. - -When using LodePNG, care has to be taken with the C version of LodePNG, as well -as the C-style structs when working with C++. The following conventions are used -for all C-style structs: - --if a struct has a corresponding init function, always call the init function when making a new one --if a struct has a corresponding cleanup function, call it before the struct disappears to avoid memory leaks --if a struct has a corresponding copy function, use the copy function instead of "=". - The destination must also be inited already. - - -4. Decoding ------------ - -Decoding converts a PNG compressed image to a raw pixel buffer. - -Most documentation on using the decoder is at its declarations in the header -above. For C, simple decoding can be done with functions such as -lodepng_decode32, and more advanced decoding can be done with the struct -LodePNGState and lodepng_decode. For C++, all decoding can be done with the -various lodepng::decode functions, and lodepng::State can be used for advanced -features. - -When using the LodePNGState, it uses the following fields for decoding: -*) LodePNGInfo info_png: it stores extra information about the PNG (the input) in here -*) LodePNGColorMode info_raw: here you can say what color mode of the raw image (the output) you want to get -*) LodePNGDecoderSettings decoder: you can specify a few extra settings for the decoder to use - -LodePNGInfo info_png --------------------- - -After decoding, this contains extra information of the PNG image, except the actual -pixels, width and height because these are already gotten directly from the decoder -functions. - -It contains for example the original color type of the PNG image, text comments, -suggested background color, etc... More details about the LodePNGInfo struct are -at its declaration documentation. - -LodePNGColorMode info_raw -------------------------- - -When decoding, here you can specify which color type you want -the resulting raw image to be. If this is different from the colortype of the -PNG, then the decoder will automatically convert the result. This conversion -always works, except if you want it to convert a color PNG to grayscale or to -a palette with missing colors. - -By default, 32-bit color is used for the result. - -LodePNGDecoderSettings decoder ------------------------------- - -The settings can be used to ignore the errors created by invalid CRC and Adler32 -chunks, and to disable the decoding of tEXt chunks. - -There's also a setting color_convert, true by default. If false, no conversion -is done, the resulting data will be as it was in the PNG (after decompression) -and you'll have to puzzle the colors of the pixels together yourself using the -color type information in the LodePNGInfo. - - -5. Encoding ------------ - -Encoding converts a raw pixel buffer to a PNG compressed image. - -Most documentation on using the encoder is at its declarations in the header -above. For C, simple encoding can be done with functions such as -lodepng_encode32, and more advanced decoding can be done with the struct -LodePNGState and lodepng_encode. For C++, all encoding can be done with the -various lodepng::encode functions, and lodepng::State can be used for advanced -features. - -Like the decoder, the encoder can also give errors. However it gives less errors -since the encoder input is trusted, the decoder input (a PNG image that could -be forged by anyone) is not trusted. - -When using the LodePNGState, it uses the following fields for encoding: -*) LodePNGInfo info_png: here you specify how you want the PNG (the output) to be. -*) LodePNGColorMode info_raw: here you say what color type of the raw image (the input) has -*) LodePNGEncoderSettings encoder: you can specify a few settings for the encoder to use - -LodePNGInfo info_png --------------------- - -When encoding, you use this the opposite way as when decoding: for encoding, -you fill in the values you want the PNG to have before encoding. By default it's -not needed to specify a color type for the PNG since it's automatically chosen, -but it's possible to choose it yourself given the right settings. - -The encoder will not always exactly match the LodePNGInfo struct you give, -it tries as close as possible. Some things are ignored by the encoder. The -encoder uses, for example, the following settings from it when applicable: -colortype and bitdepth, text chunks, time chunk, the color key, the palette, the -background color, the interlace method, unknown chunks, ... - -When encoding to a PNG with colortype 3, the encoder will generate a PLTE chunk. -If the palette contains any colors for which the alpha channel is not 255 (so -there are translucent colors in the palette), it'll add a tRNS chunk. - -LodePNGColorMode info_raw -------------------------- - -You specify the color type of the raw image that you give to the input here, -including a possible transparent color key and palette you happen to be using in -your raw image data. - -By default, 32-bit color is assumed, meaning your input has to be in RGBA -format with 4 bytes (unsigned chars) per pixel. - -LodePNGEncoderSettings encoder ------------------------------- - -The following settings are supported (some are in sub-structs): -*) auto_convert: when this option is enabled, the encoder will -automatically choose the smallest possible color mode (including color key) that -can encode the colors of all pixels without information loss. -*) btype: the block type for LZ77. 0 = uncompressed, 1 = fixed huffman tree, - 2 = dynamic huffman tree (best compression). Should be 2 for proper - compression. -*) use_lz77: whether or not to use LZ77 for compressed block types. Should be - true for proper compression. -*) windowsize: the window size used by the LZ77 encoder (1 - 32768). Has value - 2048 by default, but can be set to 32768 for better, but slow, compression. -*) force_palette: if colortype is 2 or 6, you can make the encoder write a PLTE - chunk if force_palette is true. This can used as suggested palette to convert - to by viewers that don't support more than 256 colors (if those still exist) -*) add_id: add text chunk "Encoder: LodePNG " to the image. -*) text_compression: default 1. If 1, it'll store texts as zTXt instead of tEXt chunks. - zTXt chunks use zlib compression on the text. This gives a smaller result on - large texts but a larger result on small texts (such as a single program name). - It's all tEXt or all zTXt though, there's no separate setting per text yet. - - -6. color conversions --------------------- - -An important thing to note about LodePNG, is that the color type of the PNG, and -the color type of the raw image, are completely independent. By default, when -you decode a PNG, you get the result as a raw image in the color type you want, -no matter whether the PNG was encoded with a palette, grayscale or RGBA color. -And if you encode an image, by default LodePNG will automatically choose the PNG -color type that gives good compression based on the values of colors and amount -of colors in the image. It can be configured to let you control it instead as -well, though. - -To be able to do this, LodePNG does conversions from one color mode to another. -It can convert from almost any color type to any other color type, except the -following conversions: RGB to grayscale is not supported, and converting to a -palette when the palette doesn't have a required color is not supported. This is -not supported on purpose: this is information loss which requires a color -reduction algorithm that is beyond the scope of a PNG encoder (yes, RGB to gray -is easy, but there are multiple ways if you want to give some channels more -weight). - -By default, when decoding, you get the raw image in 32-bit RGBA or 24-bit RGB -color, no matter what color type the PNG has. And by default when encoding, -LodePNG automatically picks the best color model for the output PNG, and expects -the input image to be 32-bit RGBA or 24-bit RGB. So, unless you want to control -the color format of the images yourself, you can skip this chapter. - -6.1. PNG color types --------------------- - -A PNG image can have many color types, ranging from 1-bit color to 64-bit color, -as well as palettized color modes. After the zlib decompression and unfiltering -in the PNG image is done, the raw pixel data will have that color type and thus -a certain amount of bits per pixel. If you want the output raw image after -decoding to have another color type, a conversion is done by LodePNG. - -The PNG specification gives the following color types: - -0: grayscale, bit depths 1, 2, 4, 8, 16 -2: RGB, bit depths 8 and 16 -3: palette, bit depths 1, 2, 4 and 8 -4: grayscale with alpha, bit depths 8 and 16 -6: RGBA, bit depths 8 and 16 - -Bit depth is the amount of bits per pixel per color channel. So the total amount -of bits per pixel is: amount of channels * bitdepth. - -6.2. color conversions ----------------------- - -As explained in the sections about the encoder and decoder, you can specify -color types and bit depths in info_png and info_raw to change the default -behaviour. - -If, when decoding, you want the raw image to be something else than the default, -you need to set the color type and bit depth you want in the LodePNGColorMode, -or the parameters colortype and bitdepth of the simple decoding function. - -If, when encoding, you use another color type than the default in the raw input -image, you need to specify its color type and bit depth in the LodePNGColorMode -of the raw image, or use the parameters colortype and bitdepth of the simple -encoding function. - -If, when encoding, you don't want LodePNG to choose the output PNG color type -but control it yourself, you need to set auto_convert in the encoder settings -to false, and specify the color type you want in the LodePNGInfo of the -encoder (including palette: it can generate a palette if auto_convert is true, -otherwise not). - -If the input and output color type differ (whether user chosen or auto chosen), -LodePNG will do a color conversion, which follows the rules below, and may -sometimes result in an error. - -To avoid some confusion: --the decoder converts from PNG to raw image --the encoder converts from raw image to PNG --the colortype and bitdepth in LodePNGColorMode info_raw, are those of the raw image --the colortype and bitdepth in the color field of LodePNGInfo info_png, are those of the PNG --when encoding, the color type in LodePNGInfo is ignored if auto_convert - is enabled, it is automatically generated instead --when decoding, the color type in LodePNGInfo is set by the decoder to that of the original - PNG image, but it can be ignored since the raw image has the color type you requested instead --if the color type of the LodePNGColorMode and PNG image aren't the same, a conversion - between the color types is done if the color types are supported. If it is not - supported, an error is returned. If the types are the same, no conversion is done. --even though some conversions aren't supported, LodePNG supports loading PNGs from any - colortype and saving PNGs to any colortype, sometimes it just requires preparing - the raw image correctly before encoding. --both encoder and decoder use the same color converter. - -The function lodepng_convert does the color conversion. It is available in the -interface but normally isn't needed since the encoder and decoder already call -it. - -Non supported color conversions: --color to grayscale when non-gray pixels are present: no error is thrown, but -the result will look ugly because only the red channel is taken (it assumes all -three channels are the same in this case so ignores green and blue). The reason -no error is given is to allow converting from three-channel grayscale images to -one-channel even if there are numerical imprecisions. --anything to palette when the palette does not have an exact match for a from-color -in it: in this case an error is thrown - -Supported color conversions: --anything to 8-bit RGB, 8-bit RGBA, 16-bit RGB, 16-bit RGBA --any gray or gray+alpha, to gray or gray+alpha --anything to a palette, as long as the palette has the requested colors in it --removing alpha channel --higher to smaller bitdepth, and vice versa - -If you want no color conversion to be done (e.g. for speed or control): --In the encoder, you can make it save a PNG with any color type by giving the -raw color mode and LodePNGInfo the same color mode, and setting auto_convert to -false. --In the decoder, you can make it store the pixel data in the same color type -as the PNG has, by setting the color_convert setting to false. Settings in -info_raw are then ignored. - -6.3. padding bits ------------------ - -In the PNG file format, if a less than 8-bit per pixel color type is used and the scanlines -have a bit amount that isn't a multiple of 8, then padding bits are used so that each -scanline starts at a fresh byte. But that is NOT true for the LodePNG raw input and output. -The raw input image you give to the encoder, and the raw output image you get from the decoder -will NOT have these padding bits, e.g. in the case of a 1-bit image with a width -of 7 pixels, the first pixel of the second scanline will the 8th bit of the first byte, -not the first bit of a new byte. - -6.4. A note about 16-bits per channel and endianness ----------------------------------------------------- - -LodePNG uses unsigned char arrays for 16-bit per channel colors too, just like -for any other color format. The 16-bit values are stored in big endian (most -significant byte first) in these arrays. This is the opposite order of the -little endian used by x86 CPU's. - -LodePNG always uses big endian because the PNG file format does so internally. -Conversions to other formats than PNG uses internally are not supported by -LodePNG on purpose, there are myriads of formats, including endianness of 16-bit -colors, the order in which you store R, G, B and A, and so on. Supporting and -converting to/from all that is outside the scope of LodePNG. - -This may mean that, depending on your use case, you may want to convert the big -endian output of LodePNG to little endian with a for loop. This is certainly not -always needed, many applications and libraries support big endian 16-bit colors -anyway, but it means you cannot simply cast the unsigned char* buffer to an -unsigned short* buffer on x86 CPUs. - - -7. error values ---------------- - -All functions in LodePNG that return an error code, return 0 if everything went -OK, or a non-zero code if there was an error. - -The meaning of the LodePNG error values can be retrieved with the function -lodepng_error_text: given the numerical error code, it returns a description -of the error in English as a string. - -Check the implementation of lodepng_error_text to see the meaning of each code. - -It is not recommended to use the numerical values to programmatically make -different decisions based on error types as the numbers are not guaranteed to -stay backwards compatible. They are for human consumption only. Programmatically -only 0 or non-0 matter. - - -8. chunks and PNG editing -------------------------- - -If you want to add extra chunks to a PNG you encode, or use LodePNG for a PNG -editor that should follow the rules about handling of unknown chunks, or if your -program is able to read other types of chunks than the ones handled by LodePNG, -then that's possible with the chunk functions of LodePNG. - -A PNG chunk has the following layout: - -4 bytes length -4 bytes type name -length bytes data -4 bytes CRC - -8.1. iterating through chunks ------------------------------ - -If you have a buffer containing the PNG image data, then the first chunk (the -IHDR chunk) starts at byte number 8 of that buffer. The first 8 bytes are the -signature of the PNG and are not part of a chunk. But if you start at byte 8 -then you have a chunk, and can check the following things of it. - -NOTE: none of these functions check for memory buffer boundaries. To avoid -exploits, always make sure the buffer contains all the data of the chunks. -When using lodepng_chunk_next, make sure the returned value is within the -allocated memory. - -unsigned lodepng_chunk_length(const unsigned char* chunk): - -Get the length of the chunk's data. The total chunk length is this length + 12. - -void lodepng_chunk_type(char type[5], const unsigned char* chunk): -unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type): - -Get the type of the chunk or compare if it's a certain type - -unsigned char lodepng_chunk_critical(const unsigned char* chunk): -unsigned char lodepng_chunk_private(const unsigned char* chunk): -unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk): - -Check if the chunk is critical in the PNG standard (only IHDR, PLTE, IDAT and IEND are). -Check if the chunk is private (public chunks are part of the standard, private ones not). -Check if the chunk is safe to copy. If it's not, then, when modifying data in a critical -chunk, unsafe to copy chunks of the old image may NOT be saved in the new one if your -program doesn't handle that type of unknown chunk. - -unsigned char* lodepng_chunk_data(unsigned char* chunk): -const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk): - -Get a pointer to the start of the data of the chunk. - -unsigned lodepng_chunk_check_crc(const unsigned char* chunk): -void lodepng_chunk_generate_crc(unsigned char* chunk): - -Check if the crc is correct or generate a correct one. - -unsigned char* lodepng_chunk_next(unsigned char* chunk): -const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk): - -Iterate to the next chunk. This works if you have a buffer with consecutive chunks. Note that these -functions do no boundary checking of the allocated data whatsoever, so make sure there is enough -data available in the buffer to be able to go to the next chunk. - -unsigned lodepng_chunk_append(unsigned char** out, size_t* outsize, const unsigned char* chunk): -unsigned lodepng_chunk_create(unsigned char** out, size_t* outsize, unsigned length, - const char* type, const unsigned char* data): - -These functions are used to create new chunks that are appended to the data in *out that has -length *outsize. The append function appends an existing chunk to the new data. The create -function creates a new chunk with the given parameters and appends it. Type is the 4-letter -name of the chunk. - -8.2. chunks in info_png ------------------------ - -The LodePNGInfo struct contains fields with the unknown chunk in it. It has 3 -buffers (each with size) to contain 3 types of unknown chunks: -the ones that come before the PLTE chunk, the ones that come between the PLTE -and the IDAT chunks, and the ones that come after the IDAT chunks. -It's necessary to make the distinction between these 3 cases because the PNG -standard forces to keep the ordering of unknown chunks compared to the critical -chunks, but does not force any other ordering rules. - -info_png.unknown_chunks_data[0] is the chunks before PLTE -info_png.unknown_chunks_data[1] is the chunks after PLTE, before IDAT -info_png.unknown_chunks_data[2] is the chunks after IDAT - -The chunks in these 3 buffers can be iterated through and read by using the same -way described in the previous subchapter. - -When using the decoder to decode a PNG, you can make it store all unknown chunks -if you set the option settings.remember_unknown_chunks to 1. By default, this -option is off (0). - -The encoder will always encode unknown chunks that are stored in the info_png. -If you need it to add a particular chunk that isn't known by LodePNG, you can -use lodepng_chunk_append or lodepng_chunk_create to the chunk data in -info_png.unknown_chunks_data[x]. - -Chunks that are known by LodePNG should not be added in that way. E.g. to make -LodePNG add a bKGD chunk, set background_defined to true and add the correct -parameters there instead. - - -9. compiler support -------------------- - -No libraries other than the current standard C library are needed to compile -LodePNG. For the C++ version, only the standard C++ library is needed on top. -Add the files lodepng.c(pp) and lodepng.h to your project, include -lodepng.h where needed, and your program can read/write PNG files. - -It is compatible with C90 and up, and C++03 and up. - -If performance is important, use optimization when compiling! For both the -encoder and decoder, this makes a large difference. - -Make sure that LodePNG is compiled with the same compiler of the same version -and with the same settings as the rest of the program, or the interfaces with -std::vectors and std::strings in C++ can be incompatible. - -CHAR_BITS must be 8 or higher, because LodePNG uses unsigned chars for octets. - -*) gcc and g++ - -LodePNG is developed in gcc so this compiler is natively supported. It gives no -warnings with compiler options "-Wall -Wextra -pedantic -ansi", with gcc and g++ -version 4.7.1 on Linux, 32-bit and 64-bit. - -*) Clang - -Fully supported and warning-free. - -*) Mingw - -The Mingw compiler (a port of gcc for Windows) should be fully supported by -LodePNG. - -*) Visual Studio and Visual C++ Express Edition - -LodePNG should be warning-free with warning level W4. Two warnings were disabled -with pragmas though: warning 4244 about implicit conversions, and warning 4996 -where it wants to use a non-standard function fopen_s instead of the standard C -fopen. - -Visual Studio may want "stdafx.h" files to be included in each source file and -give an error "unexpected end of file while looking for precompiled header". -This is not standard C++ and will not be added to the stock LodePNG. You can -disable it for lodepng.cpp only by right clicking it, Properties, C/C++, -Precompiled Headers, and set it to Not Using Precompiled Headers there. - -NOTE: Modern versions of VS should be fully supported, but old versions, e.g. -VS6, are not guaranteed to work. - -*) Compilers on Macintosh - -LodePNG has been reported to work both with gcc and LLVM for Macintosh, both for -C and C++. - -*) Other Compilers - -If you encounter problems on any compilers, feel free to let me know and I may -try to fix it if the compiler is modern and standards compliant. - - -10. examples ------------- - -This decoder example shows the most basic usage of LodePNG. More complex -examples can be found on the LodePNG website. - -NOTE: these examples do not support wide-character filenames, you can use an -external method to handle such files and encode or decode in-memory - -10.1. decoder C++ example -------------------------- - -#include "lodepng.h" -#include - -int main(int argc, char *argv[]) { - const char* filename = argc > 1 ? argv[1] : "test.png"; - - //load and decode - std::vector image; - unsigned width, height; - unsigned error = lodepng::decode(image, width, height, filename); - - //if there's an error, display it - if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl; - - //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ... -} - -10.2. decoder C example ------------------------ - -#include "lodepng.h" - -int main(int argc, char *argv[]) { - unsigned error; - unsigned char* image; - size_t width, height; - const char* filename = argc > 1 ? argv[1] : "test.png"; - - error = lodepng_decode32_file(&image, &width, &height, filename); - - if(error) printf("decoder error %u: %s\n", error, lodepng_error_text(error)); - - / * use image here * / - - free(image); - return 0; -} - -11. state settings reference ----------------------------- - -A quick reference of some settings to set on the LodePNGState - -For decoding: - -state.decoder.zlibsettings.ignore_adler32: ignore ADLER32 checksums -state.decoder.zlibsettings.custom_...: use custom inflate function -state.decoder.ignore_crc: ignore CRC checksums -state.decoder.ignore_critical: ignore unknown critical chunks -state.decoder.ignore_end: ignore missing IEND chunk. May fail if this corruption causes other errors -state.decoder.color_convert: convert internal PNG color to chosen one -state.decoder.read_text_chunks: whether to read in text metadata chunks -state.decoder.remember_unknown_chunks: whether to read in unknown chunks -state.info_raw.colortype: desired color type for decoded image -state.info_raw.bitdepth: desired bit depth for decoded image -state.info_raw....: more color settings, see struct LodePNGColorMode -state.info_png....: no settings for decoder but ouput, see struct LodePNGInfo - -For encoding: - -state.encoder.zlibsettings.btype: disable compression by setting it to 0 -state.encoder.zlibsettings.use_lz77: use LZ77 in compression -state.encoder.zlibsettings.windowsize: tweak LZ77 windowsize -state.encoder.zlibsettings.minmatch: tweak min LZ77 length to match -state.encoder.zlibsettings.nicematch: tweak LZ77 match where to stop searching -state.encoder.zlibsettings.lazymatching: try one more LZ77 matching -state.encoder.zlibsettings.custom_...: use custom deflate function -state.encoder.auto_convert: choose optimal PNG color type, if 0 uses info_png -state.encoder.filter_palette_zero: PNG filter strategy for palette -state.encoder.filter_strategy: PNG filter strategy to encode with -state.encoder.force_palette: add palette even if not encoding to one -state.encoder.add_id: add LodePNG identifier and version as a text chunk -state.encoder.text_compression: use compressed text chunks for metadata -state.info_raw.colortype: color type of raw input image you provide -state.info_raw.bitdepth: bit depth of raw input image you provide -state.info_raw: more color settings, see struct LodePNGColorMode -state.info_png.color.colortype: desired color type if auto_convert is false -state.info_png.color.bitdepth: desired bit depth if auto_convert is false -state.info_png.color....: more color settings, see struct LodePNGColorMode -state.info_png....: more PNG related settings, see struct LodePNGInfo - - -12. changes ------------ - -The version number of LodePNG is the date of the change given in the format -yyyymmdd. - -Some changes aren't backwards compatible. Those are indicated with a (!) -symbol. - -Not all changes are listed here, the commit history in github lists more: -https://github.com/lvandeve/lodepng - -*) 09 jan 2022: minor decoder speed improvements. -*) 27 jun 2021: added warnings that file reading/writing functions don't support - wide-character filenames (support for this is not planned, opening files is - not the core part of PNG decoding/decoding and is platform dependent). -*) 17 okt 2020: prevent decoding too large text/icc chunks by default. -*) 06 mar 2020: simplified some of the dynamic memory allocations. -*) 12 jan 2020: (!) added 'end' argument to lodepng_chunk_next to allow correct - overflow checks. -*) 14 aug 2019: around 25% faster decoding thanks to huffman lookup tables. -*) 15 jun 2019: (!) auto_choose_color API changed (for bugfix: don't use palette - if gray ICC profile) and non-ICC LodePNGColorProfile renamed to - LodePNGColorStats. -*) 30 dec 2018: code style changes only: removed newlines before opening braces. -*) 10 sep 2018: added way to inspect metadata chunks without full decoding. -*) 19 aug 2018: (!) fixed color mode bKGD is encoded with and made it use - palette index in case of palette. -*) 10 aug 2018: (!) added support for gAMA, cHRM, sRGB and iCCP chunks. This - change is backwards compatible unless you relied on unknown_chunks for those. -*) 11 jun 2018: less restrictive check for pixel size integer overflow -*) 14 jan 2018: allow optionally ignoring a few more recoverable errors -*) 17 sep 2017: fix memory leak for some encoder input error cases -*) 27 nov 2016: grey+alpha auto color model detection bugfix -*) 18 apr 2016: Changed qsort to custom stable sort (for platforms w/o qsort). -*) 09 apr 2016: Fixed colorkey usage detection, and better file loading (within - the limits of pure C90). -*) 08 dec 2015: Made load_file function return error if file can't be opened. -*) 24 okt 2015: Bugfix with decoding to palette output. -*) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding. -*) 24 aug 2014: Moved to github -*) 23 aug 2014: Reduced needless memory usage of decoder. -*) 28 jun 2014: Removed fix_png setting, always support palette OOB for - simplicity. Made ColorProfile public. -*) 09 jun 2014: Faster encoder by fixing hash bug and more zeros optimization. -*) 22 dec 2013: Power of two windowsize required for optimization. -*) 15 apr 2013: Fixed bug with LAC_ALPHA and color key. -*) 25 mar 2013: Added an optional feature to ignore some PNG errors (fix_png). -*) 11 mar 2013: (!) Bugfix with custom free. Changed from "my" to "lodepng_" - prefix for the custom allocators and made it possible with a new #define to - use custom ones in your project without needing to change lodepng's code. -*) 28 jan 2013: Bugfix with color key. -*) 27 okt 2012: Tweaks in text chunk keyword length error handling. -*) 8 okt 2012: (!) Added new filter strategy (entropy) and new auto color mode. - (no palette). Better deflate tree encoding. New compression tweak settings. - Faster color conversions while decoding. Some internal cleanups. -*) 23 sep 2012: Reduced warnings in Visual Studio a little bit. -*) 1 sep 2012: (!) Removed #define's for giving custom (de)compression functions - and made it work with function pointers instead. -*) 23 jun 2012: Added more filter strategies. Made it easier to use custom alloc - and free functions and toggle #defines from compiler flags. Small fixes. -*) 6 may 2012: (!) Made plugging in custom zlib/deflate functions more flexible. -*) 22 apr 2012: (!) Made interface more consistent, renaming a lot. Removed - redundant C++ codec classes. Reduced amount of structs. Everything changed, - but it is cleaner now imho and functionality remains the same. Also fixed - several bugs and shrunk the implementation code. Made new samples. -*) 6 nov 2011: (!) By default, the encoder now automatically chooses the best - PNG color model and bit depth, based on the amount and type of colors of the - raw image. For this, autoLeaveOutAlphaChannel replaced by auto_choose_color. -*) 9 okt 2011: simpler hash chain implementation for the encoder. -*) 8 sep 2011: lz77 encoder lazy matching instead of greedy matching. -*) 23 aug 2011: tweaked the zlib compression parameters after benchmarking. - A bug with the PNG filtertype heuristic was fixed, so that it chooses much - better ones (it's quite significant). A setting to do an experimental, slow, - brute force search for PNG filter types is added. -*) 17 aug 2011: (!) changed some C zlib related function names. -*) 16 aug 2011: made the code less wide (max 120 characters per line). -*) 17 apr 2011: code cleanup. Bugfixes. Convert low to 16-bit per sample colors. -*) 21 feb 2011: fixed compiling for C90. Fixed compiling with sections disabled. -*) 11 dec 2010: encoding is made faster, based on suggestion by Peter Eastman - to optimize long sequences of zeros. -*) 13 nov 2010: added LodePNG_InfoColor_hasPaletteAlpha and - LodePNG_InfoColor_canHaveAlpha functions for convenience. -*) 7 nov 2010: added LodePNG_error_text function to get error code description. -*) 30 okt 2010: made decoding slightly faster -*) 26 okt 2010: (!) changed some C function and struct names (more consistent). - Reorganized the documentation and the declaration order in the header. -*) 08 aug 2010: only changed some comments and external samples. -*) 05 jul 2010: fixed bug thanks to warnings in the new gcc version. -*) 14 mar 2010: fixed bug where too much memory was allocated for char buffers. -*) 02 sep 2008: fixed bug where it could create empty tree that linux apps could - read by ignoring the problem but windows apps couldn't. -*) 06 jun 2008: added more error checks for out of memory cases. -*) 26 apr 2008: added a few more checks here and there to ensure more safety. -*) 06 mar 2008: crash with encoding of strings fixed -*) 02 feb 2008: support for international text chunks added (iTXt) -*) 23 jan 2008: small cleanups, and #defines to divide code in sections -*) 20 jan 2008: support for unknown chunks allowing using LodePNG for an editor. -*) 18 jan 2008: support for tIME and pHYs chunks added to encoder and decoder. -*) 17 jan 2008: ability to encode and decode compressed zTXt chunks added - Also various fixes, such as in the deflate and the padding bits code. -*) 13 jan 2008: Added ability to encode Adam7-interlaced images. Improved - filtering code of encoder. -*) 07 jan 2008: (!) changed LodePNG to use ISO C90 instead of C++. A - C++ wrapper around this provides an interface almost identical to before. - Having LodePNG be pure ISO C90 makes it more portable. The C and C++ code - are together in these files but it works both for C and C++ compilers. -*) 29 dec 2007: (!) changed most integer types to unsigned int + other tweaks -*) 30 aug 2007: bug fixed which makes this Borland C++ compatible -*) 09 aug 2007: some VS2005 warnings removed again -*) 21 jul 2007: deflate code placed in new namespace separate from zlib code -*) 08 jun 2007: fixed bug with 2- and 4-bit color, and small interlaced images -*) 04 jun 2007: improved support for Visual Studio 2005: crash with accessing - invalid std::vector element [0] fixed, and level 3 and 4 warnings removed -*) 02 jun 2007: made the encoder add a tag with version by default -*) 27 may 2007: zlib and png code separated (but still in the same file), - simple encoder/decoder functions added for more simple usage cases -*) 19 may 2007: minor fixes, some code cleaning, new error added (error 69), - moved some examples from here to lodepng_examples.cpp -*) 12 may 2007: palette decoding bug fixed -*) 24 apr 2007: changed the license from BSD to the zlib license -*) 11 mar 2007: very simple addition: ability to encode bKGD chunks. -*) 04 mar 2007: (!) tEXt chunk related fixes, and support for encoding - palettized PNG images. Plus little interface change with palette and texts. -*) 03 mar 2007: Made it encode dynamic Huffman shorter with repeat codes. - Fixed a bug where the end code of a block had length 0 in the Huffman tree. -*) 26 feb 2007: Huffman compression with dynamic trees (BTYPE 2) now implemented - and supported by the encoder, resulting in smaller PNGs at the output. -*) 27 jan 2007: Made the Adler-32 test faster so that a timewaste is gone. -*) 24 jan 2007: gave encoder an error interface. Added color conversion from any - greyscale type to 8-bit greyscale with or without alpha. -*) 21 jan 2007: (!) Totally changed the interface. It allows more color types - to convert to and is more uniform. See the manual for how it works now. -*) 07 jan 2007: Some cleanup & fixes, and a few changes over the last days: - encode/decode custom tEXt chunks, separate classes for zlib & deflate, and - at last made the decoder give errors for incorrect Adler32 or Crc. -*) 01 jan 2007: Fixed bug with encoding PNGs with less than 8 bits per channel. -*) 29 dec 2006: Added support for encoding images without alpha channel, and - cleaned out code as well as making certain parts faster. -*) 28 dec 2006: Added "Settings" to the encoder. -*) 26 dec 2006: The encoder now does LZ77 encoding and produces much smaller files now. - Removed some code duplication in the decoder. Fixed little bug in an example. -*) 09 dec 2006: (!) Placed output parameters of public functions as first parameter. - Fixed a bug of the decoder with 16-bit per color. -*) 15 okt 2006: Changed documentation structure -*) 09 okt 2006: Encoder class added. It encodes a valid PNG image from the - given image buffer, however for now it's not compressed. -*) 08 sep 2006: (!) Changed to interface with a Decoder class -*) 30 jul 2006: (!) LodePNG_InfoPng , width and height are now retrieved in different - way. Renamed decodePNG to decodePNGGeneric. -*) 29 jul 2006: (!) Changed the interface: image info is now returned as a - struct of type LodePNG::LodePNG_Info, instead of a vector, which was a bit clumsy. -*) 28 jul 2006: Cleaned the code and added new error checks. - Corrected terminology "deflate" into "inflate". -*) 23 jun 2006: Added SDL example in the documentation in the header, this - example allows easy debugging by displaying the PNG and its transparency. -*) 22 jun 2006: (!) Changed way to obtain error value. Added - loadFile function for convenience. Made decodePNG32 faster. -*) 21 jun 2006: (!) Changed type of info vector to unsigned. - Changed position of palette in info vector. Fixed an important bug that - happened on PNGs with an uncompressed block. -*) 16 jun 2006: Internally changed unsigned into unsigned where - needed, and performed some optimizations. -*) 07 jun 2006: (!) Renamed functions to decodePNG and placed them - in LodePNG namespace. Changed the order of the parameters. Rewrote the - documentation in the header. Renamed files to lodepng.cpp and lodepng.h -*) 22 apr 2006: Optimized and improved some code -*) 07 sep 2005: (!) Changed to std::vector interface -*) 12 aug 2005: Initial release (C++, decoder only) - - -13. contact information ------------------------ - -Feel free to contact me with suggestions, problems, comments, ... concerning -LodePNG. If you encounter a PNG image that doesn't work properly with this -decoder, feel free to send it and I'll use it to find and fix the problem. - -My email address is (puzzle the account and domain together with an @ symbol): -Domain: gmail dot com. -Account: lode dot vandevenne. - - -Copyright (c) 2005-2022 Lode Vandevenne -*/