檔案Crc32校驗追加以及檔案Crc32校驗（0xEDB88320）

unsigned char AppengCrc32(unsigned char *FileName)

{

  unsigned long CRC = 0xFFFFFFFF;

  unsigned int  i;

  unsigned char Res=0;

  unsigned char Buff[513];

  unsigned int  RealRead;

  FILE          *Fp;

  unsigned short FileSize;

  Fp=fopen((const char *)FileName,"r+");

  fread(&FileSize,1,2,Fp);

  FileSize+=4;

  fseek(Fp,0,SEEK_SET);

  fwrite(&FileSize,2,1,Fp);

  fseek(Fp,0,SEEK_SET);

  if(Fp!=NULL)

  {

    for(;;)

    {

      RealRead=fread(Buff,1,512,Fp);

   if(RealRead!=0)

   {

     for(i = 0;i < RealRead;i++)

       CRC = CRC32[((CRC & 0xFF) ^ Buff[i])] ^ (CRC >> 8);

   }

   else

     break;

 }

  }

  CRC = ~CRC;

  fseek(Fp,0,SEEK_END);

  fwrite(&CRC,4,1,Fp);

  fclose(Fp);

  return 1;

}

unsigned char WinCheckCrc32(unsigned char *FileName)

{

  typedef struct

  {

    signed int   FileSize;

    signed int   AccFp   ;

    unsigned long  CrcRead;

  }TCrc32File;

  unsigned long CRC = 0xFFFFFFFF;

  signed int  i;

  unsigned char Res=0;

  unsigned char Buff[513];

  signed int  RealRead;

  TCrc32File  Crc32File;

  FILE          *Fp;

  Crc32File.AccFp=0;

  Fp=fopen(FileName,"rb");

  fseek(Fp,0,SEEK_END);                   

  Crc32File.FileSize=ftell(Fp);           

  fseek(Fp,SEEK_SET,0);                   

  if(Fp!=NULL)

  {

    for(;;)

    {

      RealRead=fread(Buff,1,512,Fp);      

      if(RealRead>0)

   {

     for(i = 0;i<RealRead;i++)

     {

         Crc32File.AccFp++;

         if(Crc32File.AccFp>Crc32File.FileSize-4) break;

         CRC = CRC32[((CRC & 0xFF) ^ Buff[i])] ^ (CRC >> 8);

     }

   }

   else

      break;

 }

  }

  CRC = ~CRC;

  fclose(Fp);

  Fp=fopen(FileName,"rb");

  fseek(Fp,-4,SEEK_END); 

  fread(&Crc32File.CrcRead,4,1,Fp);

  fclose(Fp); 

  return (Crc32File.CrcRead==CRC) ;

}