wavcrc32: Программа для проверки CRC аудиоданных, или о том, как EAC считает CRC.

/* ---------------------------------------------------------- wavcrc32.cpp Version 0.22 ---------------------------------------------------------- A program for counting audiodata CRC checksums that used in EAC (Exact Audio Copy by Andre Wiethoff) ---------------------------------------------------------- This program is freeware and open-source, you may freely redistribute or modify it, or use code in your applications. ---------------------------------------------------------- I hope this code can be compiled with any C/C++ compiler like microsoft visual c++, gcc, open-watcom c/c++, ... If you experience any problems with compiling this program you may feel free to ask me, what's the hell it is, maybe I can help you.

At this time I've checked that * gcc/g++ 3.4.4 @ cygwin * msvc 8.0 * open watcom c/c++ 1.6 work fine with this code! ---------------------------------------------------------- (c) ]DichlofoS[ Systems, 2007 mailto:dmvn@mccme.ru ---------------------------------------------------------- */

#if _MSC_VER >= 1400   // this option is for Safe STDLIB fopen_s, etc functions   #define MSC_SAFECODE 1 #else   #undef MSC_SAFECODE #endif

#include <stdio.h> #include <stdlib.h>

#if _MSC_VER >= 1400   #include <windows.h> #endif

#define SAMPLE_BUFFER_SIZE 1024

// Function prototypes void InitCRC32Table(); unsigned int Reflect(unsigned int ref, char ch); bool CheckDWORD(FILE* f, unsigned int nOffset, unsigned int nProperValue, const char* szMessage); unsigned int CheckRIFFHeader(FILE* f);

unsigned int CRC32Table[256];

// Call this function only once to initialize the CRC table void InitCRC32Table() {   unsigned int ulPolynomial = 0x04c11db7;

  // 256 values representing ASCII character codes.   for(int i = 0; i <= 0xFF; i++)   {     CRC32Table[i] = Reflect(i, 8) << 24;     for (int j = 0; j < 8; j++)       CRC32Table[i] = (CRC32Table[i] << 1) ^ (CRC32Table[i] & (1 << 31) ? ulPolynomial : 0);     CRC32Table[i] = Reflect(CRC32Table[i], 32);   } }

/*   Reflection is a requirement for the official CRC-32 standard.   You can create CRCs without it, but they won't conform to the standard.   Used only by InitCRC32Table() */ unsigned int Reflect(unsigned int ref, char ch) {   unsigned int value(0);

  // Swap bit 0 for bit 7   // bit 1 for bit 6, etc.   for (int i = 1; i < (ch + 1); i++)   {     if (ref & 1)       value |= 1 << (ch - i);     ref >>= 1;   }   return value; }

/*   Checks DWORD in WAV file on validness */ bool CheckDWORD(FILE* f, unsigned int nOffset, unsigned int nProperValue, const char* szMessage) {   unsigned int dwCheck = 0;   fseek(f, nOffset, SEEK_SET);   fread(&dwCheck, 1, 4, f);   if (dwCheck != nProperValue)   {     printf("%s\n", szMessage);     return false;   }   return true; } /*   Checks RIFF header in WAV file on validness */ unsigned int CheckRIFFHeader(FILE* f) {   if (!CheckDWORD(f, 0x00, 0x46464952, "*** non-RIFF format!")) return 0;   if (!CheckDWORD(f, 0x08, 0x45564157, "*** non-WAVE format!")) return 0;   if (!CheckDWORD(f, 0x0C, 0x20746d66, "*** cannot find format chunk!")) return 0;   if (!CheckDWORD(f, 0x10, 0x00000010, "*** invalid format chunk size!")) return 0;   if (!CheckDWORD(f, 0x14, 0x00020001, "*** invalid audio format!")) return 0;   if (!CheckDWORD(f, 0x24, 0x61746164, "*** cannot find data chunk!")) return 0;

  unsigned int dwDataSize = 0;   fseek(f, 0x28, SEEK_SET);   fread(&dwDataSize, 1, 4, f);   return dwDataSize; }

int main(int argc, char** argv) {   InitCRC32Table();

#if _MSC_VER >= 1400   DWORD StartTime = GetTickCount(); #endif

  printf("EAC wavcrc32 v0.22 (c) ]DichlofoS[ Systems, 2007\nthanx to: BakLAN, siro and other beta-testers/contributors!\n");   if (argc != 2)   {     printf("*** invalid cmdline arguments!\nsyntax: wavcrc32 filename.wav\n");     return -1;   }   const char* sFileName = argv[1];

#ifdef MSC_SAFECODE   FILE* f = 0;   fopen_s(&f, sFileName, "rb"); #else   FILE* f = fopen(sFileName, "rb"); #endif

  if (!f)   {     printf("*** cannot open file!\n");     return -1;   }   printf("file opened ok\n");

  // check header   unsigned int nDataSize = CheckRIFFHeader(f);   if (!nDataSize)   {     fclose(f);     return -1;   }   printf("RIFF header checked ok\n");

  unsigned char chBuffer[4*SAMPLE_BUFFER_SIZE];

  unsigned int nSampleCount = nDataSize >> 2;

  unsigned int crc(0xffffffff);   unsigned int crcns(0xffffffff);   unsigned int crcnsl(0xffffffff);   unsigned int crcnslr(0xffffffff);   unsigned int crcnb(0xffffffff);

  printf("please wait while couning checksums...\n");   printf("processing %d samples...\n", nSampleCount);

  unsigned int i = 0;   while (i < nSampleCount)   {     unsigned int nCurrentBlockSize = nSampleCount - i;     if (nCurrentBlockSize > SAMPLE_BUFFER_SIZE) nCurrentBlockSize = SAMPLE_BUFFER_SIZE;     if (fread(chBuffer, 1, 4*nCurrentBlockSize, f) != 4*nCurrentBlockSize)     {       printf("*** cannot read from input file!\n");       fclose(f);       printf("file closed ok\n");       return -1;     }     i += nCurrentBlockSize;     for (unsigned int k = 0; k < nCurrentBlockSize; k++)     {       unsigned char nSample[4];       *(unsigned int*)nSample = *((unsigned int*)chBuffer+k);       // calculate checksum skipping nulsamples       if (*(unsigned int*)nSample)         for (int j = 0; j < 4; j++)           crcns = (crcns >> 8) ^ CRC32Table[(crcns & 0xFF) ^ nSample[j]];       // calculate checksum skipping nulsamples on left/right channel       if (nSample[0] || nSample[1])         for (int j = 0; j < 2; j++)           crcnslr = (crcnslr >> 8) ^ CRC32Table[(crcnslr & 0xFF) ^ nSample[j]];       if (nSample[2] || nSample[3])         for (int j = 2; j < 4; j++)           crcnslr = (crcnslr >> 8) ^ CRC32Table[(crcnslr & 0xFF) ^ nSample[j]];       // calculate non-zero-bytes checksum on left channel       if (nSample[0] || nSample[1])         for (int j = 0; j < 2; j++)           crcnsl = (crcnsl >> 8) ^ CRC32Table[(crcnsl & 0xFF) ^ nSample[j]];       // calculate non-zero-bytes checksum       for (int j = 0; j < 4; j++)         if (nSample[j])           crcnb = (crcnb >> 8) ^ CRC32Table[(crcnb & 0xFF) ^ nSample[j]];

      // calculate standard checksum       for (int j = 0; j < 4; j++)         crc = (crc >> 8) ^ CRC32Table[(crc & 0xFF) ^ nSample[j]];     }   }   fclose(f);   printf("file closed ok\n");

  crc = crc^0xffffffff;   crcns = crcns^0xffffffff;   crcnsl = crcnsl^0xffffffff;   crcnslr = crcnslr^0xffffffff;   crcnb = crcnslr^0xffffffff;

  printf("--- used in EAC:\n");   printf("generic: grabbing, \"no use...\" off [all bytes]            : %08X.\n", crc);   printf("generic: grabbing, \"no use...\" on [word nulsamples l/r]   : %08X.\n", crcnslr);   printf("waveditor [word nulsamples l]                             : %08X.\n", crcnsl);   printf("--- no used in EAC, only for reference:\n");   printf("byte ignore zeros                                         : %08X.\n", crcnb);   printf("dword nulsamples                                          : %08X.\n", crcns);

#if _MSC_VER >= 1400   printf("---\ntime elapsed: %d ms\n", GetTickCount()-StartTime); #endif   return 0; }