wavcrc32

/*
----------------------------------------------------------
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;
}