Delphi - CRC32校验

网上Down的一个单元.自己改了下.

unit utCRC32;

interface

uses
  Windows,SysUtils,Classes;

const  //Crc32表
   Crc32Tab: Array[0..$FF] 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);

procedure GetCRC32Stream(aStream:TStream;var CRC32:Cardinal);

implementation

function UpdateCRC32(InitCRC: LongInt; var Buffer;
{$IFDEF Win32} Length: LongInt {$ELSE} Length: Word {$ENDIF}): LongInt;
begin
  asm
{$IFDEF Win32}
         push   esi
         push   edi
         push   eax
         push   ebx
         push   ecx
         push   edx
         lea    edi, Crc32Tab
         mov    esi, Buffer
         mov    ax, word ptr InitCRC
         mov    dx, word ptr InitCRC + 2
         mov    ecx, Length
         or     ecx, ecx
         jz     @@done
@@loop:
         xor    ebx, ebx
         mov    bl, al
         lodsb
         xor    bl, al
         mov    al, ah
         mov    ah, dl
         mov    dl, dh
         xor    dh, dh
         shl    bx, 1
         shl    bx, 1
         add    ebx, edi
         xor    ax, [ebx]
         xor    dx, [ebx + 2]
         loop   @@loop
@@done:
         mov    word ptr Result, ax
         mov    word ptr Result + 2, dx
         pop    edx
         pop    ecx
         pop    ebx
         pop    eax
         pop    edi
         pop    esi
{$ELSE}
         push   ds
         pop    es
         push   ds
         lea    di, CRC32Tab
         lds    si, Buffer
         mov    ax, word ptr InitCRC
         mov    dx, word ptr InitCRC + 2
         mov    cx, Length
         or     cx, cx
         jz     @@done
@@loop:
         xor    bh, bh
         mov    bl, al
         lodsb
         xor    bl, al
         mov    al, ah
         mov    ah, dl
         mov    dl, dh
         xor    dh, dh
         shl    bx, 1
         shl    bx, 1
         xor    ax, es:[di + bx]
         xor    dx, es:[di + bx + 2]
         loop   @@loop
@@done:
         pop    ds
         mov    word ptr Result, ax
         mov    word ptr Result + 2, dx
{$ENDIF}
  end;
end;

procedure GetCRC32Stream(aStream:TStream;var CRC32:Cardinal);
var
  Buffer:PByte;
  N:Int64;
begin
  N:=aStream.Size;
  GetMem(Buffer,N);
  try
    CRC32:=UpdateCRC32($FFFFFFFF,Buffer^,N)
  finally
    FreeMem(Buffer,N);
  end;
  CRC32 := not CRC32;
end;


end.