Вычисление CRC-32 для файла
01.01.2007
// 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 := $FFFFFFFF;
Stream := TMemoryStream.Create;
try
try
Stream.LoadFromFile(FromName);
if Stream.Size > 0 then CalcCRC32(Stream.Memory, Stream.Size, CRCvalue)
except
on E: EReadError do
error := 1
end;
CRCvalue := not CRCvalue
finally
Stream.Free
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
s: string;
CRC32: DWORD;
begin
s := 'Test String';
if CalcStringCRC32(s, CRC32) then
ShowMessage(IntToStr(crc32));
end;
Взято с сайта https://www.swissdelphicenter.ch/en/tipsindex.php
{ **** UBPFD *********** by kladovka.net.ru ****
>> Быстрый алгоритм подсчета CRC32
Использован BASM.
Зависимости: нет
Автор: Александр Шарахов, alsha@mailru.com, Москва
Copyright: Александр Шарахов
Дата: 18 января 2003 г.
********************************************** }
unit CRCunit;
interface
function GetNewCRC(OldCRC: cardinal; StPtr: pointer; StLen: integer): cardinal;
procedure UpdateCRC(StPtr: pointer; StLen: integer; var CRC: cardinal);
function GetZipCRC(StPtr: pointer; StLen: integer): cardinal;
function GetFileCRC(const FileName: string): cardinal;
implementation
var
CRCtable: array[0..255] of cardinal;
function GetNewCRC(OldCRC: cardinal; StPtr: pointer; StLen: integer): cardinal;
asm
test edx,edx;
jz @ret;
neg ecx;
jz @ret;
sub edx,ecx; // Address after last element
push ebx;
mov ebx,0; // Set ebx=0 & align @next
@next:
mov bl,al;
xor bl,byte [edx+ecx];
shr eax,8;
xor eax,cardinal [CRCtable+ebx*4];
inc ecx;
jnz @next;
pop ebx;
@ret:
end;
procedure UpdateCRC(StPtr: pointer; StLen: integer; var CRC: cardinal);
begin
CRC:=GetNewCRC(CRC,StPtr,StLen);
end;
function GetZipCRC(StPtr: pointer; StLen: integer): cardinal;
begin
Result:=not GetNewCRC($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:
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;
{ **** 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));