Вычисление CRC-32 для файла

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Code:

// The constants here are for the CRC-32 generator

// polynomial, as defined in the Microsoft

// Systems Journal, March 1995, pp. 107 - 108

const

Table: 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);

 

type

//----------------------------------crc32----------------------------------

{$IFDEF VER130}           // This is a bit awkward

   // 8-byte integer

   TInteger8 = Int64;     // Delphi 5

{$ELSE}

{$IFDEF VER120}

   TInteger8 = Int64;     // Delphi 4

{$ELSE}

   TInteger8 = COMP;      // Delphi  2 or 3

{$ENDIF}

{$ENDIF}

//----------------------------------crc32----------------------------------

 

 

// Use CalcCRC32 as a procedure so CRCValue can be passed in but

// also returned. This allows multiple calls to CalcCRC32 for

// the "same" CRC-32 calculation.

procedure CalcCRC32(p: Pointer; ByteCount: DWORD; var CRCValue: DWORD);

// The following is a little cryptic (but executes very quickly).

// The algorithm is as follows:

// 1. exclusive-or the input byte with the low-order byte of

// the CRC register to get an INDEX

// 2. shift the CRC register eight bits to the right

// 3. exclusive-or the CRC register with the contents of Table[INDEX]

// 4. repeat steps 1 through 3 for all bytes

var

i: DWORD;

q: ^BYTE;

begin

q := p;

for i := 0 to ByteCount - 1 do

begin

   CRCvalue := (CRCvalue shr 8) xor

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

   Inc(q)

end

end {CalcCRC32};

 

function CalcStringCRC32(s: string; out CRC32: DWORD): Boolean;

var

CRC32Table: DWORD;

begin

// Verify the table used to compute the CRCs has not been modified.

// Thanks to Gary Williams for this suggestion, Jan. 2003.

CRC32Table := $FFFFFFFF;

CalcCRC32(Addr(Table[0]), SizeOf(Table), CRC32Table);

CRC32Table := not CRC32Table;

 

if CRC32Table <> $6FCF9E13 then ShowMessage('CRC32 Table CRC32 is ' +

     IntToHex(Crc32Table, 8) +

     ', expecting $6FCF9E13')

else

begin

   CRC32 := $FFFFFFFF; // To match PKZIP

   if Length(s) > 0 // Avoid access violation in D4

     then CalcCRC32(Addr(s[1]), Length(s), CRC32);

   CRC32 := not CRC32; // To match PKZIP

end;

end;

 

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

var TotalBytes: TInteger8;

var error: Word);

var

Stream: TMemoryStream;

begin

error := 0;

CRCValue := $FFFFFFFF;

Stream := TMemoryStream.Create;

try

   try

     Stream.LoadFromFile(FromName);

     if Stream.Size > 0 then CalcCRC32(Stream.Memory, Stream.Size, CRCvalue)

     except

       on E: EReadError do

         error := 1

   end;

   CRCvalue := not CRCvalue

finally

   Stream.Free

end;

end;

 

procedure TForm1.Button1Click(Sender: TObject);

var

s: string;

CRC32: DWORD;

begin

s := 'Test String';

if CalcStringCRC32(s, CRC32) then

   ShowMessage(IntToStr(crc32));

end;

©Drkb::03972

Взято с сайта http://www.swissdelphicenter.ch/en/tipsindex.php

 

 

 


 

Code:

{ **** UBPFD *********** by kladovka.net.ru ****

>> 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:

Code:

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::03973


 

Code:

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

>> Расчёт контрольной суммы файла CRC-32

 

Функция находит контрольную сумму файла FileName

(полное имя файла с путём). Если возникает ошибка

(файл не найден или его нельзя открыть для чтения)

выдаётся сообщение об этом. Если это не нужно

то удалить строки с выводом сообщения.

 

Зависимости: classes, Sysutils, Dialogs;

Автор:       MegaVolt, MegaVoltik@yahoo.com

Copyright:   :( Не помню :( Взято где то в сети

несколько доработано и после обсуждения в

Дата:        3 декабря 2002 г.

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

 

unit Crc32;

 

interface

 

uses

classes, Sysutils, Dialogs;

 

function FileCRC32(const FileName: string): Cardinal;

function UpdateCRC32(InitCRC: Cardinal; BufPtr: Pointer; Len: Word): LongInt;

 

implementation

 

type

CRCTable = array[0..255] of Cardinal;

 

const

BufLen = 32768;

 

CRC32Table: CRCTable =

($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, $04FDFF252,

   $D1BB67F1, $A6BC5767, $3FB506DD, $048B2364B,

   $D80D2BDA, $AF0A1B4C, $36034AF6, $041047A60,

   $DF60EFC3, $A867DF55, $316E8EEF, $04669BE79,

 

   $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);

 

var

Buf: array[1..BufLen] of Byte;

 

function UpdateCRC32(InitCRC: Cardinal; BufPtr: Pointer; Len: Word): LongInt;

var

crc: Cardinal;

index: Integer;

i: Cardinal;

begin

crc := InitCRC;

for i := 0 to Len - 1 do

begin

   index := (crc xor Cardinal(Pointer(Cardinal(BufPtr) + i)^)) and $000000FF;

   crc := (crc shr 8) xor CRC32Table[index];

end;

Result := crc;

end;

 

function FileCRC32(const FileName: string): Cardinal;

var

InFile: TFileStream;

crc32: Cardinal;

Res: Integer;

BufPtr: Pointer;

begin

BufPtr := @Buf;

crc32 := $FFFFFFFF;

try

   InFile := TFileStream.Create(FileName, fmShareDenyNone);

   Res := InFile.Read(Buf, BufLen);

   while (Res <> 0) do

   begin

     crc32 := UpdateCrc32(crc32, BufPtr, Res);

     Res := InFile.Read(Buf, BufLen);

   end;

   InFile.Destroy;

except

   on E: Exception do

   begin

     if Assigned(InFile) then

       InFile.Free;

     ShowMessage(Format('При обработке файла [%s] вышла ' +

       'вот такая oшибочка [%s]', [FileName, E.Message]));

   end;

end;

Result := not crc32;

end;

 

end.

//Пример использования:

 

var

i: cardinal;

begin

i := FileCRC32('c:\autoexec.bat');

ShowMessage('Контрольная сумма файла = ' IntToStr(i));

 

©Drkb::03974