CRC32

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Code:

{©Drkb v.3(2007): www.drkb.ru,

®Vit (Vitaly Nevzorov) - nevzorov@yahoo.com}

 

function CRC32(const IniCRC:Integer;Source:AnsiString):Integer;

asm

Push EBX

Push ESI

Push EDI

Or EDX,EDX

Jz @Done

Mov ESI,EDX

Mov ECX,[EDX-4]

Jecxz @Done

Lea EDI,@CRCTbl

Mov EDX,EAX

Xor EAX,EAX

Cld

@L1:

Lodsb

Mov EBX,EDX

Xor EBX,EAX

And EBX,$FF

Shl EBX,2

Shr EDX,8

And EDX,$FFFFFF

Xor EDX,[EDI+EBX]

Dec ECX

Jnz @L1

Mov EAX,EDX

@Done:

Pop EDI

Pop ESI

Pop EBX

Ret

@CRCTbl:

DD $00000000, $77073096, $ee0e612c, $990951ba

DD $076dc419, $706af48f, $e963a535, $9e6495a3

DD $0edb8832, $79dcb8a4, $e0d5e91e, $97d2d988

DD $09b64c2b, $7eb17cbd, $e7b82d07, $90bf1d91

DD $1db71064, $6ab020f2, $f3b97148, $84be41de

DD $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7

DD $136c9856, $646ba8c0, $fd62f97a, $8a65c9ec

DD $14015c4f, $63066cd9, $fa0f3d63, $8d080df5

DD $3b6e20c8, $4c69105e, $d56041e4, $a2677172

DD $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b

DD $35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940

DD $32d86ce3, $45df5c75, $dcd60dcf, $abd13d59

DD $26d930ac, $51de003a, $c8d75180, $bfd06116

DD $21b4f4b5, $56b3c423, $cfba9599, $b8bda50f

DD $2802b89e, $5f058808, $c60cd9b2, $b10be924

DD $2f6f7c87, $58684c11, $c1611dab, $b6662d3d

DD $76dc4190, $01db7106, $98d220bc, $efd5102a

DD $71b18589, $06b6b51f, $9fbfe4a5, $e8b8d433

DD $7807c9a2, $0f00f934, $9609a88e, $e10e9818

DD $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01

DD $6b6b51f4, $1c6c6162, $856530d8, $f262004e

DD $6c0695ed, $1b01a57b, $8208f4c1, $f50fc457

DD $65b0d9c6, $12b7e950, $8bbeb8ea, $fcb9887c

DD $62dd1ddf, $15da2d49, $8cd37cf3, $fbd44c65

DD $4db26158, $3ab551ce, $a3bc0074, $d4bb30e2

DD $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb

DD $4369e96a, $346ed9fc, $ad678846, $da60b8d0

DD $44042d73, $33031de5, $aa0a4c5f, $dd0d7cc9

DD $5005713c, $270241aa, $be0b1010, $c90c2086

DD $5768b525, $206f85b3, $b966d409, $ce61e49f

DD $5edef90e, $29d9c998, $b0d09822, $c7d7a8b4

DD $59b33d17, $2eb40d81, $b7bd5c3b, $c0ba6cad

DD $edb88320, $9abfb3b6, $03b6e20c, $74b1d29a

DD $ead54739, $9dd277af, $04db2615, $73dc1683

DD $e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8

DD $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1

DD $f00f9344, $8708a3d2, $1e01f268, $6906c2fe

DD $f762575d, $806567cb, $196c3671, $6e6b06e7

DD $fed41b76, $89d32be0, $10da7a5a, $67dd4acc

DD $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5

DD $d6d6a3e8, $a1d1937e, $38d8c2c4, $4fdff252

DD $d1bb67f1, $a6bc5767, $3fb506dd, $48b2364b

DD $d80d2bda, $af0a1b4c, $36034af6, $41047a60

DD $df60efc3, $a867df55, $316e8eef, $4669be79

DD $cb61b38c, $bc66831a, $256fd2a0, $5268e236

DD $cc0c7795, $bb0b4703, $220216b9, $5505262f

DD $c5ba3bbe, $b2bd0b28, $2bb45a92, $5cb36a04

DD $c2d7ffa7, $b5d0cf31, $2cd99e8b, $5bdeae1d

DD $9b64c2b0, $ec63f226, $756aa39c, $026d930a

DD $9c0906a9, $eb0e363f, $72076785, $05005713

DD $95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38

DD $92d28e9b, $e5d5be0d, $7cdcefb7, $0bdbdf21

DD $86d3d2d4, $f1d4e242, $68ddb3f8, $1fda836e

DD $81be16cd, $f6b9265b, $6fb077e1, $18b74777

DD $88085ae6, $ff0f6a70, $66063bca, $11010b5c

DD $8f659eff, $f862ae69, $616bffd3, $166ccf45

DD $a00ae278, $d70dd2ee, $4e048354, $3903b3c2

DD $a7672661, $d06016f7, $4969474d, $3e6e77db

DD $aed16a4a, $d9d65adc, $40df0b66, $37d83bf0

DD $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9

DD $bdbdf21c, $cabac28a, $53b39330, $24b4a3a6

DD $bad03605, $cdd70693, $54de5729, $23d967bf

DD $b3667a2e, $c4614ab8, $5d681b02, $2a6f2b94

DD $b40bbe37, $c30c8ea1, $5a05df1b, $2d02ef8d

end;

 

 

 

©Drkb::03967

Автор: Vit (www.delphist.com, www.drkb.ru, www.unihighlighter.com, www.nevzorov.org)

Взято с Vingrad.ru http://forum.vingrad.ru

 

 


 

Code:

{ **** UBPFD *********** by delphibase.endimus.com ****

>> Быстрый алгоритм подсчета CRC32

 

Использован BASM.

 

Зависимости: нет

Автор:       Александр Шарахов, alsha@mailru.com, Москва

Copyright:   Александр Шарахов

Дата:        18 января 2003 г.

***************************************************** }

 

unit CRCunit;

 

interface

function GetNewCRC(OldCRC: cardinal; StPtr: pointer; StLen: integer): cardinal;

procedure UpdateCRC(StPtr: pointer; StLen: integer; var CRC: cardinal);

function GetZipCRC(StPtr: pointer; StLen: integer): cardinal;

function GetFileCRC(const FileName: string): cardinal;

 

implementation

var

CRCtable: array[0..255] of cardinal;

 

function GetNewCRC(OldCRC: cardinal; StPtr: pointer; StLen: integer): cardinal;

asm

test edx,edx;

jz @ret;

neg ecx;

jz @ret;

sub edx,ecx; // Address after last element

 

push ebx;

mov ebx,0; // Set ebx=0 & align @next

@next:

mov bl,al;

xor bl,byte [edx+ecx];

shr eax,8;

xor eax,cardinal [CRCtable+ebx*4];

inc ecx;

jnz @next;

pop ebx;

 

@ret:

end;

 

procedure UpdateCRC(StPtr: pointer; StLen: integer; var CRC: cardinal);

begin

CRC := GetNewCRC(CRC, StPtr, StLen);

end;

 

function GetZipCRC(StPtr: pointer; StLen: integer): cardinal;

begin

Result := not GetNewCRC($FFFFFFFF, StPtr, StLen);

end;

 

function GetFileCRC(const FileName: string): cardinal;

const

BufSize = 64 * 1024;

var

Fi: file;

pBuf: PChar;

Count: integer;

begin

Assign(Fi, FileName);

Reset(Fi, 1);

GetMem(pBuf, BufSize);

Result := $FFFFFFFF;

repeat

   BlockRead(Fi, pBuf^, BufSize, Count);

   if Count = 0 then

     break;

   Result := GetNewCRC(Result, pBuf, Count);

until false;

Result := not Result;

FreeMem(pBuf);

CloseFile(Fi);

end;

 

procedure CRCInit;

var

c: cardinal;

i, j: integer;

begin

for i := 0 to 255 do

begin

   c := i;

   for j := 1 to 8 do

     if odd(c) then

       c := (c shr 1) xor $EDB88320

     else

       c := (c shr 1);

   CRCtable[i] := c;

end;

end;

 

initialization

CRCinit;

end.

 

//Пример использования:

 

uses

CRCunit;

 

procedure TForm1.Button1Click(Sender: TObject);

const

FileName = 'CRCunit.pas';

begin

ShowMessage('CRC32 файла=' + IntToHex(GetFileCRC(FileName), 8));

ShowMessage('CRC32 имени=' + IntToHex(GetZipCRC(PChar(FileName),

   Length(FileName)), 8));

end;

 

©Drkb::03968

 


 

Приведен модуль для Delphi 1.0 (для Delphi 2.0 должны быть сделаны небольшие изменения):

 

 

Code:

unit CRC32;

 

{CRC32 рассчитывает код циклической избыточности (cyclic redundancy code - CRC),

известный как CRC-32, с использованием алгоритма byte-wise ("мудрый байт").

 

(C) Авторские права 1989, 1995-1996 Earl F. Glynn, Overland Park, KS.

Все права защищены.

 

Данный модуль является производным от программы CRCT FORTRAN 77, опубликованной

в "Byte-wise CRC Calculations" за авторством Aram Perez из IEEE Micro, Июнь 1983,

страницы 40-50. Константы для полиномиального генератора CRC-32, приведенные

здесь, опубликованы в "Microsoft Systems Journal", Март 1995, страницы 107-108.

 

Данный CRC алгоритм имеет бОльшую скорость за счет 512 элементов таблицы

поиска.}

 

interface

 

procedure CalcCRC32(p: pointer; nbyte: WORD; var CRCvalue: LongInt);

procedure CalcFileCRC32(FromName: string; var CRCvalue: LongInt;

var IOBuffer: pointer; BufferSize: WORD; var TotalBytes: LongInt;

var error: WORD);

 

implementation

 

const

table: 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);

 

type

buffer = array[1..65521] of BYTE; { самый большой буфер, который     }

{ только можно распределить в Куче }

var

i: WORD;

q: ^buffer;

 

procedure CalcCRC32(p: pointer; nbyte: WORD; var CRCvalue: LongInt);

{Ниже выполняется небольшое криптование (но выполняется очень быстро).

Алгоритм работает следующим образом:

1.  совершаем операцию "И/ИЛИ" (XOR) входного байта с младшей

частью регистра CRC для получения INDEX

2.  сдвигаем регистр CRC на восемь битов вправо

3.  совершаем операцию "И/ИЛИ" (XOR) с CRC регистром и

Table[INDEX]

4.  повторяем шаги с 1 по 3 для всех байтов }

begin

q := p;

for i := 1 to nBYTE do

   CRCvalue := (CRCvalue shr 8) xor

     Table[q^[i] xor (CRCvalue and $000000FF)]

end {CalcCRC32};

 

procedure CalcFileCRC32(FromName: string; var CRCvalue: LongInt;

var IOBuffer: pointer; BufferSize: WORD; var TotalBytes: LongInt;

var error: WORD);

var

BytesRead: WORD;

FromFile: file;

i: WORD;

begin

FileMode := 0; {Turbo по умолчанию 2 для R/W и 0 для R/O}

CRCValue := $FFFFFFFF;

ASSIGN(FromFile, FromName);

{$I-}RESET(FromFile, 1);

{$I+}

error := IOResult;

if error = 0 then

begin

   TotalBytes := 0;

   repeat

     BlockRead(FromFile, IOBuffer^, BufferSize, BytesRead);

     CalcCRC32(IOBuffer, BytesRead, CRCvalue);

     INC(TotalBytes, BytesRead)

   until BytesRead = 0;

   CLOSE(FromFile)

end;

CRCvalue := not CRCvalue

end {CalcFileCRC32};

 

end {CRC}.

 

 

©Drkb::03969

http://delphiworld.narod.ru/

DelphiWorld 6.0