crc32.pas

软件功能：32位图形界面程序

unit Crc32; 

interface 

uses 
  Windows, DsgnIntf, Classes, SysUtils{$IFNDEF NOFORMS},dialogs,
  Forms{$ENDIF};

function GetCrc32(s: string; Seed: LongInt): string; 
function GetCrc32ForFile(AFileName: string; Seed: LongInt): string; 
function GetCrc32ForStream(filename:string; Seed: Longint): String;
FUNCTION Calc_STR(FFStream:Tstream;myofset:longint;ofnum:byte;isbegin,isencode:boolean;Enint:integer):int64;
FUNCTION Calc_CRC(filename : string;myofset:longint;ofnum:byte;isbegin,isencode:boolean;Enint:integer):integer;
const
  buffer_size  = 8192;
VAR     FCRC_buffer      : array[1..buffer_size] of byte;
    FCRC32           : DWord;
implementation

//uses Windows, SysUtils; 

const CrcTbl: array [0..255] of DWORD = 
  ( $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); 

function GetCrc32(s: string; Seed: LongInt): string; 
  var Count: Integer; 
      CrcVal: LongInt; 
  begin 
    CrcVal := Seed; 
    for Count := 1 to Length(s) do 
      CrcVal := CrcTbl[Byte(CrcVal xor DWORD(Ord(s[Count])))] xor ((CrcVal shr 8) and $00FFFFFF); 
    Result := IntToHex(not(CrcVal), 8); 
  end; 

function GetCrc32ForFile(AFileName: string; Seed: LongInt): string; 
var 
  Buf : Array[1..1000] of char; 
  BufLen : Integer; 
  Count: Word; 
  CRCVal: Longint; 
  hFile : Integer; 
  BytesRead : Word; 

  begin 
    Result := ''; 
    CRCVal := Seed; 
    hFile := FileOpen(AFileName, 0); 
    if hFile = -1 then 
      exit; 
    try 
      repeat 
        BytesRead := FileRead(hFile, Buf, SizeOf(Buf)); 
        if BytesRead > 0 then 
          for Count := 0 to BytesRead - 1 do 
            CRCVal := CrcTbl[Byte(CRCVal xor LongInt(Buf[Count]))] xor ((CRCVal shr 8) and $00FFFFFF); 
      until BytesRead = 0; 
      Result := IntToHex(not(CRCVal), 8); 
    finally 
      FileClose(hFile); 
    end; 
  end; 

function GetCrc32ForStream(filename:string; Seed: Longint): String;
var 
  Buf : Array[1..1000] of char; 
  BufLen : Integer; 
  Count: Word; 
  CRCVal: Longint; 
  AStream:tmemorystream;
  temstream:tfilestream;
begin 
  Result := ''; 
  CRCVal := Seed; 
  try
  temstream:=tfilestream.create(filename,$0040);
  TEMstream.Seek(0,sofrombeginning);
  AStream:=tmemorystream.create;
  astream.CopyFrom(temstream,temstream.size-4);
  temstream.free;
  repeat
    BufLen := AStream.Read(Buf, 1000);
    if BufLen > 0 then
      for Count := 0 to BufLen - 1 do
        CRCVal := CrcTbl[Byte(CRCVal xor LongInt(Buf[Count]))] xor ((CRCVal shr 8) and $00FFFFFF);
  until BufLen < 1000;
  Result := IntToHex(not(CRCVal), 8);
  finally
  astream.free;
  end;

end;

FUNCTION Calc_CRC(filename : string;myofset:longint;ofnum:byte;isbegin,isencode:boolean;Enint:integer):integer;
var
 FFStream : TFileStream;
 stream:tmemorystream;
 sz,im,i     : integer;
 CRC : DWord;
begin
  crc:=0;
  result:=crc;

  try
   stream:=tmemorystream.create; 
   ffstream:=TFileStream.Create(filename, fmOpenRead or fmShareDenyWrite);
   if isbegin then
   begin
   ffstream.Seek(0,sofrombeginning);
   stream.CopyFrom(ffstream,myofset);
   ffstream.Seek(myofset+ofnum,sofrombeginning);
   stream.CopyFrom(ffstream,ffstream.size-(myofset+ofnum));
   end else
   begin
   ffstream.Seek(-myofset,sofromend);
   stream.CopyFrom(ffstream,myofset);
   ffstream.Seek(0,sofrombeginning);
   stream.CopyFrom(ffstream,ffstream.size-(myofset+ofnum));
   end;
   ffstream.free;
   stream.Seek(0,sofrombeginning);
   
   while (stream.Position<>stream.Size) do
     begin
       sz:=stream.Read(fcrc_buffer, sizeof(fcrc_buffer));
       for i:=1 to sz do
        begin
        CRC:=((CRC SHR ofnum) AND $FFFFFF) XOR CrcTbl[(CRC XOR dword(fcrc_buffer[i]) or (CRC SHl ofnum)) AND $EF];
        end;
       Application.ProcessMessages;
     end;

   FINALLY
   stream.Free;
   end;
if isencode then
result:=crc - crc div Enint + 37 xor Enint shr 3 else
result:=crc;
end;

FUNCTION Calc_STR(FFStream:Tstream;myofset:longint;ofnum:byte;isbegin,isencode:boolean;Enint:integer):int64;
var
 stream:tmemorystream;
 sz,im,i     : integer;
 CRC : DWord;
begin
  crc:=0;
  result:=crc;

  try
   stream:=tmemorystream.create;

   if isbegin then
   begin
   FFStream.Seek(0,sofrombeginning);
   stream.CopyFrom(ffstream,myofset);
   FFStream.Seek(myofset+ofnum,sofrombeginning);
   stream.CopyFrom(FFStream,ffstream.size-(myofset+ofnum));
   end else
   begin
   FFStream.Seek(-myofset,sofromend);
   stream.CopyFrom(ffstream,myofset);
   ffstream.Seek(0,sofrombeginning);
   stream.CopyFrom(ffstream,ffstream.size-(myofset+ofnum));
   end;
   ffstream.free;
   stream.Seek(0,sofrombeginning);
   
   while (stream.Position<>stream.Size) do
     begin
       sz:=stream.Read(fcrc_buffer, sizeof(fcrc_buffer));
       for i:=1 to sz do
        begin
        CRC:=((CRC SHR ofnum) AND $FFFFFF) XOR CrcTbl[(CRC XOR dword(fcrc_buffer[i]) or (CRC SHl ofnum)) AND $EF];
        end;
       Application.ProcessMessages;
     end;

   FINALLY
   stream.Free;
   end;
if isencode then
result:=crc - crc div Enint + 37 xor Enint shr 3 else
result:=crc;
end;

end.