116 lines
5.1 KiB
C
Executable file
116 lines
5.1 KiB
C
Executable file
/* (C) 2001-2008 Timothy B. Terriberry
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(C) 2008 Jean-Marc Valin */
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of the Xiph.org Foundation nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#if !defined(cc6__entenc_H)
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# define cc6__entenc_H (1)
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# include <stddef.h>
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# include "cc6_entcode.h"
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typedef struct cc6_ec_enc cc6_ec_enc;
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/*The entropy encoder.*/
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struct cc6_ec_enc{
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/*Buffered output.*/
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cc6_ec_byte_buffer *buf;
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/*A buffered output symbol, awaiting carry propagation.*/
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int rem;
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/*Number of extra carry propagating symbols.*/
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size_t ext;
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/*The number of values in the current range.*/
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cc6_ec_uint32 rng;
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/*The low end of the current range (inclusive).*/
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cc6_ec_uint32 low;
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};
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/*Initializes the encoder.
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_buf: The buffer to store output bytes in.
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This must have already been initialized for writing and reset.*/
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void cc6_ec_enc_init(cc6_ec_enc *_this,cc6_ec_byte_buffer *_buf);
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/*Encodes a symbol given its frequency information.
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The frequency information must be discernable by the decoder, assuming it
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has read only the previous symbols from the stream.
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It is allowable to change the frequency information, or even the entire
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source alphabet, so long as the decoder can tell from the context of the
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previously encoded information that it is supposed to do so as well.
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_fl: The cumulative frequency of all symbols that come before the one to be
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encoded.
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_fh: The cumulative frequency of all symbols up to and including the one to
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be encoded.
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Together with _fl, this defines the range [_fl,_fh) in which the
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decoded value will fall.
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_ft: The sum of the frequencies of all the symbols*/
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void cc6_ec_encode(cc6_ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft);
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void cc6_ec_encode_bin(cc6_ec_enc *_this,unsigned _fl,unsigned _fh,unsigned bits);
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/*Encodes a sequence of raw bits in the stream.
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_fl: The bits to encode.
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_ftb: The number of bits to encode.
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This must be at least one, and no more than 32.*/
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void cc6_ec_enc_bits(cc6_ec_enc *_this,cc6_ec_uint32 _fl,int _ftb);
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/*Encodes a sequence of raw bits in the stream.
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_fl: The bits to encode.
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_ftb: The number of bits to encode.
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This must be at least one, and no more than 64.*/
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void cc6_ec_enc_bits64(cc6_ec_enc *_this,cc6_ec_uint64 _fl,int _ftb);
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/*Encodes a raw unsigned integer in the stream.
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_fl: The integer to encode.
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_ft: The number of integers that can be encoded (one more than the max).
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This must be at least one, and no more than 2**32-1.*/
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void cc6_ec_enc_uint(cc6_ec_enc *_this,cc6_ec_uint32 _fl,cc6_ec_uint32 _ft);
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/*Encodes a raw unsigned integer in the stream.
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_fl: The integer to encode.
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_ft: The number of integers that can be encoded (one more than the max).
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This must be at least one, and no more than 2**64-1.*/
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void cc6_ec_enc_uint64(cc6_ec_enc *_this,cc6_ec_uint64 _fl,cc6_ec_uint64 _ft);
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/*Returns the number of bits "used" by the encoded symbols so far.
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The actual number of bits may be larger, due to rounding to whole bytes, or
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smaller, due to trailing zeros that can be stripped, so this is not an
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estimate of the true packet size.
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This same number can be computed by the decoder, and is suitable for making
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coding decisions.
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_b: The number of extra bits of precision to include.
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At most 16 will be accurate.
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Return: The number of bits scaled by 2**_b.
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This will always be slightly larger than the exact value (e.g., all
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rounding error is in the positive direction).*/
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long cc6_ec_enc_tell(cc6_ec_enc *_this,int _b);
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/*Indicates that there are no more symbols to encode.
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All reamining output bytes are flushed to the output buffer.
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cc6_ec_enc_init() must be called before the encoder can be used again.*/
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void cc6_ec_enc_done(cc6_ec_enc *_this);
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#endif
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