preparations for protocol (CRC class added)

src/global.h

@@ -103,6 +103,20 @@
 #define _MAXBYTE						255 /* binary: 11111111 */
 #define _MINSHORT						(-32768)
 
+#if HAVE_STDINT_H
+# include <stdint.h>
+#elif HAVE_INTTYPES_H
+# include <inttypes.h>
+#elif defined ( _WIN32 )
+typedef unsigned __int32 uint32_t;
+typedef unsigned __int16 uint16_t;
+typedef unsigned __int8  uint8_t;
+#else
+typedef unsigned int   uint32_t;
+typedef unsigned short uint16_t;
+typedef unsigned char  uint8_t;
+#endif
+
 
 /* Definitions for window message system ------------------------------------ */
 typedef unsigned int					_MESSAGE_IDENT;

src/protocol.cpp

@@ -4,6 +4,20 @@
  * Author(s):
  *	Volker Fischer
  *
+
+Protocol message definition
+
+   +-----------+------------+-----------------+--------------+-------------+
+   | 2 byte ID | 1 byte cnt | 2 byte length n | n bytes data | 2 bytes CRC |
+   +-----------+------------+-----------------+--------------+-------------+
+
+- message ID defined by the defines PROTMESSID_x
+- cnt: counter which is incremet for each message and wraps around at 255
+- length n in bytes of the data
+- actual data, dependent on message type
+- 16 bits CRC, calculating over the entire message, is transmitted inverted
+  Generator polynom: G_16(x) = x^16 + x^12 + x^5 + 1, initial state: all ones
+
  *
  ******************************************************************************
  *

src/protocol.h

@@ -28,6 +28,13 @@
 #include "global.h"
 
 
+/* Definitions ****************************************************************/
+// protocol message IDs
+#define PROTMESSID_ACKN				 0 // acknowledge
+#define PROTMESSID_JITT_BUF_SIZE	10 // jitter buffer size
+#define PROTMESSID_PING				11 // for measuring ping time
+
+
 /* Classes ********************************************************************/
 class CProtocol
 {
@@ -59,5 +66,15 @@ protected:
 
 };
 
+class CProtMessage
+{
+public:
+	CProtMessage () {}
+	virtual ~CProtMessage () {}
+
+protected:
+
+};
+
 
 #endif /* !defined(PROTOCOL_H__3B123453_4344_BB2392354455IUHF1912__INCLUDED_) */

src/util.cpp

@@ -72,20 +72,50 @@ double CSignalLevelMeter::MicLevel ()
 }
 
 
-/* Global functions implementation ********************************************/
-void DebugError(const char* pchErDescr, const char* pchPar1Descr, 
-				const double dPar1, const char* pchPar2Descr,
-				const double dPar2)
+/* CRC ---------------------------------------------------------------------- */
+void CCRC::Reset ()
 {
-	FILE* pFile = fopen("DebugError.dat", "a");
-	fprintf(pFile, pchErDescr); fprintf(pFile, " ### ");
-	fprintf(pFile, pchPar1Descr); fprintf(pFile, ": ");
-	fprintf(pFile, "%e ### ", dPar1);
-	fprintf(pFile, pchPar2Descr); fprintf(pFile, ": ");
-	fprintf(pFile, "%e\n", dPar2);
-	fclose(pFile);
-	printf("\nDebug error! For more information see test/DebugError.dat\n");
-	exit(1);
+	/* Init state shift-register with ones. Set all registers to "1" with
+	   bit-wise not operation */
+	iStateShiftReg = ~uint32_t ( 0 );
+}
+
+void CCRC::AddByte ( const uint8_t byNewInput )
+{
+	for ( int i = 0; i < 8; i++ )
+	{
+		/* Shift bits in shift-register for transistion */
+		iStateShiftReg <<= 1;
+
+		/* Take bit, which was shifted out of the register-size and place it
+		   at the beginning (LSB)
+		   (If condition is not satisfied, implicitely a "0" is added) */
+		if ( ( iStateShiftReg & iBitOutMask) > 0 )
+		{
+			iStateShiftReg |= 1;
+		}
+
+		/* Add new data bit to the LSB */
+		if ( ( byNewInput & ( 1 << ( 8 - i - 1 ) ) ) > 0 )
+		{
+			iStateShiftReg ^= 1;
+		}
+
+		/* Add mask to shift-register if first bit is true */
+		if ( iStateShiftReg & 1 )
+		{
+			iStateShiftReg ^= iPoly;
+		}
+	}
+}
+
+uint32_t CCRC::GetCRC()
+{
+	/* Return inverted shift-register (1's complement) */
+	iStateShiftReg = ~iStateShiftReg;
+
+	/* Remove bit which where shifted out of the shift-register frame */
+	return iStateShiftReg & ( iBitOutMask - 1 );
 }
 
 
@@ -316,3 +346,22 @@ CLlconHelpMenu::CLlconHelpMenu ( QWidget* parent ) : QPopupMenu ( parent )
 	insertSeparator();
 	insertItem ( tr ( "&About..." ), this, SLOT ( OnHelpAbout () ) );
 }
+
+
+/******************************************************************************\
+* Global functions implementation                                              *
+\******************************************************************************/
+void DebugError(const char* pchErDescr, const char* pchPar1Descr, 
+				const double dPar1, const char* pchPar2Descr,
+				const double dPar2)
+{
+	FILE* pFile = fopen("DebugError.dat", "a");
+	fprintf(pFile, pchErDescr); fprintf(pFile, " ### ");
+	fprintf(pFile, pchPar1Descr); fprintf(pFile, ": ");
+	fprintf(pFile, "%e ### ", dPar1);
+	fprintf(pFile, pchPar2Descr); fprintf(pFile, ": ");
+	fprintf(pFile, "%e\n", dPar2);
+	fclose(pFile);
+	printf("\nDebug error! For more information see test/DebugError.dat\n");
+	exit(1);
+}

src/util.h

@@ -381,6 +381,26 @@ protected:
 };
 
 
+/* CRC ---------------------------------------------------------------------- */
+class CCRC
+{
+public:
+	CCRC () : iPoly ( ( 1 << 5 ) | ( 1 << 12 ) ), iBitOutMask ( 1 << 16 )
+		{ Reset (); }
+	virtual ~CCRC () {}
+
+	void Reset ();
+	void AddByte ( const uint8_t byNewInput );
+	bool CheckCRC ( const uint32_t iCRC ) { return iCRC == GetCRC(); }
+	uint32_t GetCRC ();
+
+protected:
+	uint32_t iBitOutMask;
+	uint32_t iPoly;
+	uint32_t iStateShiftReg;
+};
+
+
 /* Time conversion ---------------------------------------------------------- */
 // needed for ping measurement
 class CTimeConv