{
  $Project$
  $Workfile$
  $Revision$
  $DateUTC$
  $Id$

  This file is part of the Indy (Internet Direct) project, and is offered
  under the dual-licensing agreement described on the Indy website.
  (http://www.indyproject.org/)

  Copyright:
   (c) 1993-2005, Chad Z. Hower and the Indy Pit Crew. All rights reserved.
}
{
  $Log$
}
{
  Rev 1.4    28.09.2004 21:37:20  Andreas Hausladen
  Added Typecast to surpress Delphi 5 compiler warning

  Rev 1.3    2004.02.03 5:44:48 PM  czhower
  Name changes

  Rev 1.2    24/01/2004 19:20:52  CCostelloe
  Cleaned up warnings

  Rev 1.1    2003-10-16 11:06:28  HHellström
  Fixed for dotNET

  Rev 1.0    11/13/2002 08:30:40 AM  JPMugaas
  Initial import from FTP VC.
}

unit IdHashCRC;

interface
{$i IdCompilerDefines.inc}

uses
  IdGlobal,
  IdHash;

type
  TIdHashCRC16 = class(TIdHash16)
  public
    procedure HashStart(var VRunningHash : UInt16); override;
    procedure HashByte(var VRunningHash : UInt16; const AByte : Byte); override;
  end;

  TIdHashCRC32 = class(TIdHash32)
  public
    procedure HashStart(var VRunningHash : UInt32); override;
    procedure HashEnd(var VRunningHash : UInt32); override;
    procedure HashByte(var VRunningHash : UInt32; const AByte : Byte); override;
  end;

implementation

const
  CRC16Table: array[0..255] of UInt16 =
  ( $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 UInt32 = (
    $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 }

procedure TIdHashCRC16.HashStart(var VRunningHash: UInt16);
begin
  VRunningHash := 0;
end;

procedure TIdHashCRC16.HashByte(var VRunningHash: UInt16; const AByte: Byte);
begin
  VRunningHash := (VRunningHash shr 8) xor CRC16Table[AByte xor (VRunningHash and $FF)];
end;

{ TIdHashCRC32 }

procedure TIdHashCRC32.HashStart(var VRunningHash: UInt32);
begin
  VRunningHash := $FFFFFFFF;
end;

procedure TIdHashCRC32.HashEnd(var VRunningHash : UInt32);
begin
  VRunningHash := VRunningHash xor $FFFFFFFF;
end;

procedure TIdHashCRC32.HashByte(var VRunningHash: UInt32; const AByte: Byte);
begin
  VRunningHash := ((VRunningHash shr 8) and $00FFFFFF) xor CRC32Table[(VRunningHash xor AByte) and $FF];
end;

end.