www.pudn.com > Indy_9_00_14_src.zip > IdHashCRC.pas
{ $HDR$}
{**********************************************************************}
{ Unit archived using Team Coherence }
{ Team Coherence is Copyright 2002 by Quality Software Components }
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{ $Log: 10179: IdHashCRC.pas
{
{ Rev 1.0 2002.11.12 10:40:08 PM czhower
}
unit IdHashCRC;
{
2001-Oct-23 Pete Mee
- Fixed CRC-32.
}
interface
uses
Classes,
IdHash;
type
TIdHashCRC16 = class(TIdHash16)
public
function HashValue(AStream: TStream): Word; override;
end;
TIdHashCRC32 = class(TIdHash32)
public
function HashValue(AStream: TStream): LongWord; override;
end;
implementation
uses
SysUtils;
const
CRC16Table: array[0..255] OF WORD =
($0000,$C0C1,$C181,$0140,$C301,$03C0,$0280,$C241,$C601,$06C0,$0780,
$C741,$0500,$C5C1,$C481,$0440,$CC01,$0CC0,$0D80,$CD41,$0F00,$CFC1,
$CE81,$0E40,$0A00,$CAC1,$CB81,$0B40,$C901,$09C0,$0880,$C841,$D801,
$18C0,$1980,$D941,$1B00,$DBC1,$DA81,$1A40,$1E00,$DEC1,$DF81,$1F40,
$DD01,$1DC0,$1C80,$DC41,$1400,$D4C1,$D581,$1540,$D701,$17C0,$1680,
$D641,$D201,$12C0,$1380,$D341,$1100,$D1C1,$D081,$1040,$F001,$30C0,
$3180,$F141,$3300,$F3C1,$F281,$3240,$3600,$F6C1,$F781,$3740,$F501,
$35C0,$3480,$F441,$3C00,$FCC1,$FD81,$3D40,$FF01,$3FC0,$3E80,$FE41,
$FA01,$3AC0,$3B80,$FB41,$3900,$F9C1,$F881,$3840,$2800,$E8C1,$E981,
$2940,$EB01,$2BC0,$2A80,$EA41,$EE01,$2EC0,$2F80,$EF41,$2D00,$EDC1,
$EC81,$2C40,$E401,$24C0,$2580,$E541,$2700,$E7C1,$E681,$2640,$2200,
$E2C1,$E381,$2340,$E101,$21C0,$2080,$E041,$A001,$60C0,$6180,$A141,
$6300,$A3C1,$A281,$6240,$6600,$A6C1,$A781,$6740,$A501,$65C0,$6480,
$A441,$6C00,$ACC1,$AD81,$6D40,$AF01,$6FC0,$6E80,$AE41,$AA01,$6AC0,
$6B80,$AB41,$6900,$A9C1,$A881,$6840,$7800,$B8C1,$B981,$7940,$BB01,
$7BC0,$7A80,$BA41,$BE01,$7EC0,$7F80,$BF41,$7D00,$BDC1,$BC81,$7C40,
$B401,$74C0,$7580,$B541,$7700,$B7C1,$B681,$7640,$7200,$B2C1,$B381,
$7340,$B101,$71C0,$7080,$B041,$5000,$90C1,$9181,$5140,$9301,$53C0,
$5280,$9241,$9601,$56C0,$5780,$9741,$5500,$95C1,$9481,$5440,$9C01,
$5CC0,$5D80,$9D41,$5F00,$9FC1,$9E81,$5E40,$5A00,$9AC1,$9B81,$5B40,
$9901,$59C0,$5880,$9841,$8801,$48C0,$4980,$8941,$4B00,$8BC1,$8A81,
$4A40,$4E00,$8EC1,$8F81,$4F40,$8D01,$4DC0,$4C80,$8C41,$4400,$84C1,
$8581,$4540,$8701,$47C0,$4680,$8641,$8201,$42C0,$4380,$8341,$4100,
$81C1,$8081,$4040);
CRC32Table : array[0..255] of longword = (
$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);
{ TIdHashCRC16 }
function TIdHashCRC16.HashValue(AStream: TStream): Word;
var
i: Integer;
Buf: byte;
begin
Result := 0;
for i := 1 to AStream.Size do begin
AStream.ReadBuffer(Buf, SizeOf(Buf));
Result := Hi(Result) xor CRC16Table[ Buf xor Lo(Result)];
end;
end;
{ TIdHashCRC32 }
function TIdHashCRC32.HashValue(AStream: TStream): LongWord;
var
i: Integer;
LByte: Byte;
begin
Result := $FFFFFFFF;
// Faster than a while - While would read .Size which is slow
for i := 1 to AStream.Size do begin
//TODO: See if this and Elf would be faster by reading into a larger buffer and scanning that
//buffer.
AStream.ReadBuffer(LByte, SizeOf(LByte));
Result := ((Result shr 8) and $00FFFFFF) xor CRC32Table[(Result xor LByte) and $FF];
end;
Result := Result xor $FFFFFFFF;
end;
end.