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CRC32的算法,该如何解决

发布时间： 2012-03-03 15:33:03 作者： rapoo

CRC32的算法
软件需要实现以下几个功能，这些功能整合在一个软件中。
1、待计算数据串输入
待计算数据串在软件界面中输入。
待计算数据串由多个字节（16进制表示，总长度不固定）组成（ep：0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07）,用户软件应提供一个友好的界面，实现待计算数据串的输入。
2、CRC32校验值计算
根据CRC32标准算法对输入数据串进行计算，生成输入数据串的CRC32检验码，生成多项式为：
X32+X30+ X27 +X25+X22+X20+X13+X12+X11+X10+X8+X7+X6+X5+X4+X0
检验码初始值为0x00FF0000。
3、计算结果显示
软件界面应能显示最终的CRC32检验码。


以上是需求，关键是如何用代码来实现CRC32的计算，请教高手。

[解决办法]
http://blog.csdn.net/ksaiy/archive/2004/12/23/226960.aspx
[解决办法]
crc32单元文件。。。


Delphi(Pascal) code
unit Crc32;interfaceuses  Windows;function ComputeFileCRC32(const FileName : String) : DWORD;function UpdateCRC32(InitCRC : DWORD; BufPtr : Pointer; Len : Word) : LongInt;implementationtype  CRCTable = array [0..255] of DWORD;const  BufLen = 32768;  CRC32Table : CRCTable =    ($00000000, $77073096, $ee0e612c, $990951ba,     $076dc419, $706af48f, $e963a535, $9e6495a3,     $0edb8832, $79dcb8a4, $e0d5e91e, $97d2d988,     $09b64c2b, $7eb17cbd, $e7b82d07, $90bf1d91,     $1db71064, $6ab020f2, $f3b97148, $84be41de,     $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7,     $136c9856, $646ba8c0, $fd62f97a, $8a65c9ec,     $14015c4f, $63066cd9, $fa0f3d63, $8d080df5,     $3b6e20c8, $4c69105e, $d56041e4, $a2677172,     $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b,     $35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940,     $32d86ce3, $45df5c75, $dcd60dcf, $abd13d59,     $26d930ac, $51de003a, $c8d75180, $bfd06116,     $21b4f4b5, $56b3c423, $cfba9599, $b8bda50f,     $2802b89e, $5f058808, $c60cd9b2, $b10be924,     $2f6f7c87, $58684c11, $c1611dab, $b6662d3d,     $76dc4190, $01db7106, $98d220bc, $efd5102a,     $71b18589, $06b6b51f, $9fbfe4a5, $e8b8d433,     $7807c9a2, $0f00f934, $9609a88e, $e10e9818,     $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01,     $6b6b51f4, $1c6c6162, $856530d8, $f262004e,     $6c0695ed, $1b01a57b, $8208f4c1, $f50fc457,     $65b0d9c6, $12b7e950, $8bbeb8ea, $fcb9887c,     $62dd1ddf, $15da2d49, $8cd37cf3, $fbd44c65,     $4db26158, $3ab551ce, $a3bc0074, $d4bb30e2,     $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb,     $4369e96a, $346ed9fc, $ad678846, $da60b8d0,     $44042d73, $33031de5, $aa0a4c5f, $dd0d7cc9,     $5005713c, $270241aa, $be0b1010, $c90c2086,     $5768b525, $206f85b3, $b966d409, $ce61e49f,     $5edef90e, $29d9c998, $b0d09822, $c7d7a8b4,     $59b33d17, $2eb40d81, $b7bd5c3b, $c0ba6cad,     $edb88320, $9abfb3b6, $03b6e20c, $74b1d29a,     $ead54739, $9dd277af, $04db2615, $73dc1683,     $e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8,     $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1,     $f00f9344, $8708a3d2, $1e01f268, $6906c2fe,     $f762575d, $806567cb, $196c3671, $6e6b06e7,     $fed41b76, $89d32be0, $10da7a5a, $67dd4acc,     $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5,     $d6d6a3e8, $a1d1937e, $38d8c2c4, $04fdff252,     $d1bb67f1, $a6bc5767, $3fb506dd, $048b2364b,     $d80d2bda, $af0a1b4c, $36034af6, $041047a60,     $df60efc3, $a867df55, $316e8eef, $04669be79,     $cb61b38c, $bc66831a, $256fd2a0, $5268e236,     $cc0c7795, $bb0b4703, $220216b9, $5505262f,     $c5ba3bbe, $b2bd0b28, $2bb45a92, $5cb36a04,     $c2d7ffa7, $b5d0cf31, $2cd99e8b, $5bdeae1d,     $9b64c2b0, $ec63f226, $756aa39c, $026d930a,     $9c0906a9, $eb0e363f, $72076785, $05005713,     $95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38,     $92d28e9b, $e5d5be0d, $7cdcefb7, $0bdbdf21,     $86d3d2d4, $f1d4e242, $68ddb3f8, $1fda836e,     $81be16cd, $f6b9265b, $6fb077e1, $18b74777,     $88085ae6, $ff0f6a70, $66063bca, $11010b5c,     $8f659eff, $f862ae69, $616bffd3, $166ccf45,     $a00ae278, $d70dd2ee, $4e048354, $3903b3c2,     $a7672661, $d06016f7, $4969474d, $3e6e77db,     $aed16a4a, $d9d65adc, $40df0b66, $37d83bf0,     $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9,     $bdbdf21c, $cabac28a, $53b39330, $24b4a3a6,     $bad03605, $cdd70693, $54de5729, $23d967bf,     $b3667a2e, $c4614ab8, $5d681b02, $2a6f2b94,     $b40bbe37, $c30c8ea1, $5a05df1b, $2d02ef8d);var  Buf : array [1..BufLen] of Byte;function UpdateCRC32(InitCRC : DWORD; BufPtr : Pointer; Len : Word) : LongInt;var  crc   : DWORD;  index : Integer;  i     : DWORD;begin  crc := InitCRC;  for i:=0 to Len-1 do begin    index := (crc  xor DWORD(Pointer(DWORD(BufPtr)+i)^)) and $000000FF;    crc := ((crc shr 8) and $00FFFFFF) xor CRC32Table[index];  end;  Result := crc;end;function ComputeFileCRC32(const FileName : String) : DWORD;var   InFile : file;   crc32  : DWORD;   Res    : Integer;   BufPtr : Pointer;   OldFM  : Byte;begin   BufPtr := @Buf;   OldFM := FileMode;   FileMode := 0;   Assign(InFile,FileName);   Reset(InFile,1);   crc32 := $FFFFFFFF;   repeat     BlockRead(InFile,Buf,BufLen,Res);     crc32 := UpdateCrc32(crc32,BufPtr,Res);   until Eof(InFile);   Close(InFile);   FileMode := OldFM;   crc32 := not crc32;   Result := crc32;end;end. 
 
[解决办法]
[code=C]/C++ 
 template <typename valueType> 
 class crc 
 { 
 private: 
 ///  <summary> 
 /// CRC查询表 
 ///  </summary> 
 valueType Crcs[256]; 
 public: 
 ///  <summary> 
 /// 初始化CRC查询表 
 ///  </summary> 
 ///  <param name="code">多项式值(不包含第一个2进制0) </param> 
 crc(valueType code) 
 { 
 set(code); 
 } 
  
 ///  <summary> 
 /// 根据多项式值生成查询表 
 ///  </summary> 
 ///  <param name="code">多项式值(不包含第一个2进制0) </param> 
 void set(valueType code) 
 { 
 valueType value; 
 for (byte bit, index = 255; index != 0; --index) 
 { 
 for (value = index, bit = 8; bit != 0; --bit) 
 { 
 if ((value & 1) == 1) value = (value >> 1) ^ code; 
 else value >>= 1; 
 } 
 Crcs[index] = value; 
 } 
 Crcs[0] = 0; 
 } 
  
 ///  <summary> 
 /// 计算CRC检验值 
 ///  </summary> 
 ///  <param name="value">CRC检验值 </param> 
 ///  <param name="data">数据地址 </param> 
 ///  <param name="length">数据临时量 </param> 
 #ifdef PLATFORM_64BIT 
 #define CRC(value, data, dataValue) dataValue = *(uint*)(data);\ 
 value = Crcs[(byte)(value ^ dataValue)] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8); 
 #else 
 #define CRC(value, data, dataValue) dataValue = *(uint*)(data);\ 
 value = Crcs[(byte)(value ^ dataValue)] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8);\ 
 value = Crcs[(byte)(value ^ (dataValue >>= 8))] ^ (value >> 8); 
 #endif 
 ///  <summary> 
 /// 获取CRC检验值 
 ///  </summary> 
 ///  <param name="data">数据 </param> 
 ///  <param name="length">数据长度 </param> 
 ///  <returns>CRC检验值 </returns> 
 valueType get(byte *data, int32 length) 
 { 
 if(data == NULL && length  <= 0) throw showjim::sys::exception::indexOverflow; 
 uint dataValue; 
 valueType value = (valueType)UINTBYTE(ff); 
 byte right = (byte)data & (CPUBYTE - 1); 
 if(right != 0) 
 { 
 dataValue = *(uint*)(data - right) >> (right  < < 3); 
 byte left = CPUBYTE - right; 
 data += left; 
 if(left >= length) 
 { 
 left = length; 
 length = 0; 
 } 
 else length -= left; 
 do 
 { 
 value = Crcs[(byte)(value ^ (valueType)dataValue)] ^ (value >> 8); 
 dataValue >>= 8; 
 } 
 while(--left != 0); 
 } 
 right = length & (CPUBIT - 1); 
 for(byte *end = data + length - right; data != end; data += CPUBIT) 
 { 
 CRC(value, data, dataValue); 
 CRC(value, data + CPUBYTE, dataValue);  
 
 CRC(value, data + CPUBYTE * 2, dataValue); 
 CRC(value, data + CPUBYTE * 3, dataValue); 
 CRC(value, data + CPUBYTE * 4, dataValue); 
 CRC(value, data + CPUBYTE * 5, dataValue); 
 CRC(value, data + CPUBYTE * 6, dataValue); 
 CRC(value, data + CPUBYTE * 7, dataValue); 
 } 
 if((right & (CPUBIT >> 1)) != 0) 
 { 
 CRC(value, data, dataValue); 
 CRC(value, data + CPUBYTE, dataValue); 
 CRC(value, data + CPUBYTE * 2, dataValue); 
 CRC(value, data + CPUBYTE * 3, dataValue); 
 data += CPUBIT >> 1; 
 } 
 if((right & (CPUBIT >> 2)) != 0) 
 { 
 CRC(value, data, dataValue); 
 CRC(value, data + CPUBYTE, dataValue); 
 data += CPUBIT >> 2; 
 } 
 if((right & (CPUBIT >> 3)) != 0) 
 { 
 CRC(value, data, dataValue); 
 data += CPUBIT >> 3; 
 } 
 if((right &= (CPUBYTE - 1)) != 0) 
 { 
 dataValue = *(uint*)data; 
 do 
 { 
 value = Crcs[(byte)(value ^ dataValue)] ^ (value >> 8); 
 dataValue >>= 8; 
 } 
 while(--right != 0); 
 } 
 return ~value; 
 } 
  
 ///  <summary> 
 /// 获取CRC检验值 
 ///  </summary> 
 ///  <param name="code">多项式值(不包含第一个2进制0) </param> 
 ///  <param name="data">数据 </param> 
 ///  <param name="length">数据长度 </param> 
 ///  <returns>CRC检验值 </returns> 
 inline static valueType value(valueType code, byte *data, int32 length) 
 { 
 return crc(code).get(data, length); 
 } 
 }; 
 [/code]
get函数简单的写，其实就是一个个字节读的循环
[code=C]/C++ 
 uint32 get(byte *data, int32 length) 
 { 
 uint32 value = 0xffffffffUL; 
 for(byte *end = data + length; data != end; ++data) value = Crcs[(byte)(value ^ *data)] ^ (value >> 8); 
 return ~value; 
 } 
 [/code]
[解决办法]
某世界级软件公司泄露代码中的CRC32实现。把公司名称去了，看代码风格应该知道是哪家。


/*++

Module Name:

   crc32.h

Abstract:

   CRC-32 alogorithm prototypes and constants

--*/



//////////////////////////////////////////////////////////////
//
// Function prototypes for CRC-32
//
//////////////////////////////////////////////////////////////


#ifdef __cplusplus
extern "C"
{
#endif

void
Crc32(  unsigned long crc,
       unsigned long cbBuffer,
       void * pvBuffer,
       unsigned long * pNewCrc);

#ifdef __cplusplus
}
#endif





/*++

Module Name:

   crc32.c

Abstract:

   CRC-32 alogorithm

   31-Mar-94       MikeSw      Created
   25-Jul-96       ChandanS    Copied from net\svcdlls\ntlmssp\client\crc32.c
   27-Jan-07       MikeSw      Incorporated x86 ASM code for performance

--*/

#include "crc32.h"

#ifdef KMODE_NTLM
#ifdef ALLOC_PRAGMA
#pragma alloc_text("PAGEMSG", Crc32)
#endif  // ALLOC_PRAGMA
#endif  // KMODE

//
// This code comes from Dr. Dobbs Journal, May 1992
//


unsigned long CRCTable[256] = {
   0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F,
   0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
   0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2,
   0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
   0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 
 
   0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
   0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
   0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
   0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423,
   0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
   0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106,
   0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
   0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
   0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
   0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
   0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
   0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7,
   0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
   0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA,
   0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
   0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
   0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
   0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84,
   0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
   0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
   0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
   0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E,
   0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
   0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55,
   0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
   0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28,
   0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
   0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F,
   0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
   0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
   0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
   0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69,
   0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
   0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
   0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
   0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693,
   0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
   0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D };


void
Crc32(  unsigned long dwCrc,
       unsigned long cbBuffer,
       void * pvBuffer,
       unsigned long * pNewCrc)
{
 unsigned char * pbBuffer;

#ifdef _X86_
_asm
{
 mov     ecx, DWORD PTR cbBuffer
 shr     ecx, 2
 mov     eax, ecx
 dec     ecx
 mov     esi, DWORD PTR pvBuffer

 mov     edx, DWORD PTR dwCrc
 test    eax, eax
 je      SHORT $LABEL2
 inc     ecx
$LABEL1:
 mov     ebx, DWORD PTR [esi]
 add     esi, 4

 mov     eax, ebx
 shr     ebx, 8
 xor     eax, edx
 and     eax, 0FFh
 shr     edx, 8
 mov     edi, DWORD PTR CRCTable[eax*4]
 xor     edx, edi

 mov     eax, ebx
 shr     ebx, 8
 xor     eax, edx
 and     eax, 0FFh
 shr     edx, 8
 mov     edi, DWORD PTR CRCTable[eax*4]
 xor     edx, edi

 mov     eax, ebx
 shr     ebx, 8
 xor     eax, edx
 and     eax, 0FFh
 shr     edx, 8
 mov     edi, DWORD PTR CRCTable[eax*4] 
 
 xor     edx, edi

 mov     eax, ebx
;  shr     ebx, 8  -- Not needed on last byte
 xor     eax, edx
 and     eax, 0FFh
 shr     edx, 8
 mov     edi, DWORD PTR CRCTable[eax*4]
 xor     edx, edi

 dec     ecx
 jne     SHORT $LABEL1
$LABEL2:
 mov     DWORD PTR dwCrc, edx
 mov     DWORD PTR pbBuffer, esi
}

   cbBuffer &= 0x3;
#else // _X86_
   pbBuffer = (unsigned char *) pvBuffer;
#endif
   while (cbBuffer-- != 0)
   {
       dwCrc = (dwCrc >> 8) ^ CRCTable[(unsigned char) dwCrc ^ *pbBuffer++];
   }
   *pNewCrc = dwCrc;

}






[解决办法]
我百度的不是很懂！希望对你有帮助
下面是产生CRC-32校验吗的子程序。  
unsigned long crc_32_tab[256]={  
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,0x0edb8832,…, 0x5a05df1b, 0x2d02ef8d  
};//事先计算出的参数表，共有256项，未全部列出。  

unsigned long GenerateCRC32(char xdata * DataBuf,unsigned long len)  
{  
unsigned long oldcrc32;  
unsigned long crc32;  
unsigned long oldcrc;  
unsigned int charcnt;  
char c,t;  
oldcrc32 = 0x00000000; //初值为0  
charcnt=0;  
while (len--) {  
t= (oldcrc32 >> 24) & 0xFF; //要移出的字节的值  
oldcrc=crc_32_tab[t]; //根据移出的字节的值查表  
c=DataBuf[charcnt]; //新移进来的字节值  
oldcrc32= (oldcrc32 << 8) | c; //将新移进来的字节值添在寄存器末字节中  
oldcrc32=oldcrc32^oldcrc; //将寄存器与查出的值进行xor运算  
charcnt++;  
}  
crc32=oldcrc32;  
return crc32;  
}  
参数表可以先在PC机上算出来，也可在程序初始化时完成。下面是用于计算参数表的c语言子程序，在Visual C++ 6.0下编译通过。  
#include <stdio.h>  
unsigned long int crc32_table[256];  
unsigned long int ulPolynomial = 0x04c11db7;  
unsigned long int Reflect(unsigned long int ref, char ch)  
{ unsigned long int value(0);  
// 交换bit0和bit7，bit1和bit6，类推  
for(int i = 1; i < (ch + 1); i++)  
{ if(ref & 1)  
value |= 1 << (ch - i);  
ref >>= 1; }  
return value;  
}  
init_crc32_table()  
{ unsigned long int crc,temp;  
// 256个值  
for(int i = 0; i <= 0xFF; i++)  
{ temp=Reflect(i, 8);  
crc32_table[i]= temp<< 24;  
for (int j = 0; j < 8; j++){  
unsigned long int t1,t2;  
unsigned long int flag=crc32_table[i]&0x80000000;  
t1=(crc32_table[i] << 1);  
if(flag==0)  
t2=0;  
else  
t2=ulPolynomial;  
crc32_table[i] =t1^t2 ; }  
crc=crc32_table[i];  
crc32_table[i] = Reflect(crc32_table[i], 32);  
}  
}
[解决办法]
Delphi(Pascal) code
unit CRC32;{32 Bit CRC, polynomial (used in Zip and others)}interface(************************************************************************* DESCRIPTION     :  32 Bit CRC REQUIREMENTS    :  D4-D7/D9-D10/D12, FPC EXTERNAL DATA   :  --- MEMORY USAGE    :  --- DISPLAY MODE    :  --- REFERENCES      :  --- Version  Date      Author      Modification -------  --------  -------     ------------------------------------------ 0.10     29.09.07  W.Ehrhardt  Initial version based on standard v3.07 0.11     12.11.08  we          uses BTypes, Ptr2Inc and/or Str255/Str127 0.12     19.07.09  we          D12 fix: assign with typecast string(fname)**************************************************************************)(*------------------------------------- (C) Copyright 2002-2009 Wolfgang Ehrhardt This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not    claim that you wrote the original software. If you use this software in    a product, an acknowledgment in the product documentation would be    appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be    misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution.----------------------------------------*){$i STD.INC}uses  BTypes;procedure CRC32Init(var CRC: longint);  {-initialize context}  {$ifdef DLL} stdcall; {$endif}procedure CRC32Update(var CRC: longint; Msg: pointer; Len: word);  {-update CRC32 with Msg data}  {$ifdef DLL} stdcall; {$endif}procedure CRC32Final(var CRC: longint);  {-CRC32: finalize calculation}  {$ifdef DLL} stdcall; {$endif}function  CRC32SelfTest: boolean;  {-Self test for CRC32}  {$ifdef DLL} stdcall; {$endif}procedure CRC32Full(var CRC: longint; Msg: pointer; Len: word);  {-CRC32 of Msg with init/update/final}  {$ifdef DLL} stdcall; {$endif}procedure CRC32File(const fname: Str255; var CRC: longint; var buf; bsize: word; var Err: word);  {-CRC32 of file, buf: buffer with at least bsize bytes}  {$ifdef DLL} stdcall; {$endif}procedure CRC32UpdateXL(var CRC: longint; Msg: pointer; Len: longint);  {-update CRC32 with Msg data}  {$ifdef DLL} stdcall; {$endif}procedure CRC32FullXL(var CRC: longint; Msg: pointer; Len: longint);  {-CRC32 of Msg with init/update/final}  {$ifdef DLL} stdcall; {$endif}implementationconst  Mask32 = longint($FFFFFFFF);{$ifdef StrictLong}  {$warnings off}  {$R-} {avoif D9 errors!}{$endif}const  CTab: array[0..255] of longint = (    $00000000,$77073096,$ee0e612c,$990951ba,$076dc419,$706af48f,$e963a535,$9e6495a3,    $0edb8832,$79dcb8a4,$e0d5e91e,$97d2d988,$09b64c2b,$7eb17cbd,$e7b82d07,$90bf1d91,    $1db71064,$6ab020f2,$f3b97148,$84be41de,$1adad47d,$6ddde4eb,$f4d4b551,$83d385c7,    $136c9856,$646ba8c0,$fd62f97a,$8a65c9ec,$14015c4f,$63066cd9,$fa0f3d63,$8d080df5,    $3b6e20c8,$4c69105e,$d56041e4,$a2677172,$3c03e4d1,$4b04d447,$d20d85fd,$a50ab56b,    $35b5a8fa,$42b2986c,$dbbbc9d6,$acbcf940,$32d86ce3,$45df5c75,$dcd60dcf,$abd13d59,    $26d930ac,$51de003a,$c8d75180,$bfd06116,$21b4f4b5,$56b3c423,$cfba9599,$b8bda50f,    $2802b89e,$5f058808,$c60cd9b2,$b10be924,$2f6f7c87,$58684c11,$c1611dab,$b6662d3d,    $76dc4190,$01db7106,$98d220bc,$efd5102a,$71b18589,$06b6b51f,$9fbfe4a5,$e8b8d433,    $7807c9a2,$0f00f934,$9609a88e,$e10e9818,$7f6a0dbb,$086d3d2d,$91646c97,$e6635c01,    $6b6b51f4,$1c6c6162,$856530d8,$f262004e,$6c0695ed,$1b01a57b,$8208f4c1,$f50fc457,    $65b0d9c6,$12b7e950,$8bbeb8ea,$fcb9887c,$62dd1ddf,$15da2d49,$8cd37cf3,$fbd44c65,    $4db26158,$3ab551ce,$a3bc0074,$d4bb30e2,$4adfa541,$3dd895d7,$a4d1c46d,$d3d6f4fb,    $4369e96a,$346ed9fc,$ad678846,$da60b8d0,$44042d73,$33031de5,$aa0a4c5f,$dd0d7cc9,    $5005713c,$270241aa,$be0b1010,$c90c2086,$5768b525,$206f85b3,$b966d409,$ce61e49f,    $5edef90e,$29d9c998,$b0d09822,$c7d7a8b4,$59b33d17,$2eb40d81,$b7bd5c3b,$c0ba6cad,    $edb88320,$9abfb3b6,$03b6e20c,$74b1d29a,$ead54739,$9dd277af,$04db2615,$73dc1683,    $e3630b12,$94643b84,$0d6d6a3e,$7a6a5aa8,$e40ecf0b,$9309ff9d,$0a00ae27,$7d079eb1,    $f00f9344,$8708a3d2,$1e01f268,$6906c2fe,$f762575d,$806567cb,$196c3671,$6e6b06e7,    $fed41b76,$89d32be0,$10da7a5a,$67dd4acc,$f9b9df6f,$8ebeeff9,$17b7be43,$60b08ed5,    $d6d6a3e8,$a1d1937e,$38d8c2c4,$4fdff252,$d1bb67f1,$a6bc5767,$3fb506dd,$48b2364b,    $d80d2bda,$af0a1b4c,$36034af6,$41047a60,$df60efc3,$a867df55,$316e8eef,$4669be79,    $cb61b38c,$bc66831a,$256fd2a0,$5268e236,$cc0c7795,$bb0b4703,$220216b9,$5505262f,    $c5ba3bbe,$b2bd0b28,$2bb45a92,$5cb36a04,$c2d7ffa7,$b5d0cf31,$2cd99e8b,$5bdeae1d,    $9b64c2b0,$ec63f226,$756aa39c,$026d930a,$9c0906a9,$eb0e363f,$72076785,$05005713,    $95bf4a82,$e2b87a14,$7bb12bae,$0cb61b38,$92d28e9b,$e5d5be0d,$7cdcefb7,$0bdbdf21,    $86d3d2d4,$f1d4e242,$68ddb3f8,$1fda836e,$81be16cd,$f6b9265b,$6fb077e1,$18b74777,    $88085ae6,$ff0f6a70,$66063bca,$11010b5c,$8f659eff,$f862ae69,$616bffd3,$166ccf45,    $a00ae278,$d70dd2ee,$4e048354,$3903b3c2,$a7672661,$d06016f7,$4969474d,$3e6e77db,    $aed16a4a,$d9d65adc,$40df0b66,$37d83bf0,$a9bcae53,$debb9ec5,$47b2cf7f,$30b5ffe9,    $bdbdf21c,$cabac28a,$53b39330,$24b4a3a6,$bad03605,$cdd70693,$54de5729,$23d967bf,    $b3667a2e,$c4614ab8,$5d681b02,$2a6f2b94,$b40bbe37,$c30c8ea1,$5a05df1b,$2d02ef8d);{$ifdef StrictLong}  {$warnings on}  {$ifdef RangeChecks_on}    {$R+}  {$endif}{$endif}{---------------------------------------}procedure CRC32Update(var CRC: longint; Msg: pointer; Len: word);  {-update CRC32 with Msg data}begin  CRC32UpdateXL(CRC, Msg, Len);end;{---------------------------------------}procedure CRC32UpdateXL(var CRC: longint; Msg: pointer; Len: longint);  {-update CRC32 with Msg data}var  i: longint;begin  for i:=1 to Len do begin    CRC := CTab[byte(CRC) xor PByte(Msg)^] xor (CRC shr 8);    inc(Ptr2Inc(Msg));  end;end;{---------------------------------------}procedure CRC32FullXL(var CRC: longint; Msg: pointer; Len: longint);  {-CRC32 of Msg with init/update/final}begin  CRC32Init(CRC);  CRC32UpdateXL(CRC, Msg, Len);  CRC32Final(CRC);end;{---------------------------------------}procedure CRC32Init(var CRC: longint);  {-CRC initialization}begin  CRC := Mask32;end;{---------------------------------------}procedure CRC32Final(var CRC: longint);  {-CRC32: finalize calculation}begin  CRC := CRC xor Mask32;end;{---------------------------------------}procedure CRC32Full(var CRC: longint; Msg: pointer; Len: word);  {-CRC32 of Msg with init/update/final}begin  CRC32Init(CRC);  CRC32Update(CRC, Msg, Len);  CRC32Final(CRC);end;{---------------------------------------}function  CRC32SelfTest: boolean;  {-self test for CRC32}const  s: string[17] = '0123456789abcdefg';  Check = longint($BE6CBE90);var  i: integer;  CRC, CRCF: longint;begin  CRC32Full(CRCF, @s[1], length(s));  CRC32Init(CRC);  for i:=1 to length(s) do CRC32Update(CRC, @s[i], 1);  CRC32Final(CRC);  CRC32SelfTest := (CRC=Check) and (CRCF=Check);end;{$i-} {Force I-}{---------------------------------------}procedure CRC32File(const fname: Str255; var CRC: longint; var buf; bsize: word; var Err: word);  {-CRC32 of file, buf: buffer with at least bsize bytes}var  fms: byte;  L: longint;  f: file;begin  fms := FileMode;  FileMode := 0;  system.assign(f,{$ifdef D12Plus} string {$endif} (fname));  system.reset(f,1);  Err := IOResult;  FileMode := fms;  if Err<>0 then exit;  CRC32Init(CRC);  L := bsize;  while (Err=0) and (L=bsize) do begin    system.blockread(f,buf,bsize,L);    Err := IOResult;    CRC32UpdateXL(CRC, @buf, L);  end;  system.close(f);  if IOResult=0 then;  CRC32Final(CRC);end;end.
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