CRC-код файла

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MakNik (2003-10-09 15:07) [0]

Подскажите, пожалуйста, как получить CRC-код файла? Может у кого есть готовая функция??? Заранее спасибо.

← →
HolACost! (2003-10-09 15:17) [1]

http://algolist.manual.ru/

← →
yaJohn (2003-10-09 15:19) [2]

{
*** CRC 32 Optimized for speed ***
*** by Filip Skalka, fip@post.cz ***
*** August 2002 ***
}

unit CRC32;
interface

function CalculateCRC32(var buffer;const size:longword):longword;
function CalculateCRC32Masked(var buffer;const size:longword):longword;

implementation
uses sysutils;

type
TData=array [0..0] of byte;

const
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);

{function CalculateCRC32(var buffer;const size:longword):longword;
var i:integer;
data:tdata absolute buffer;
begin
result:=0;
for i:=0 to size-1 do result:=(result shr 8) xor (CRC32Table[byte(result) xor data[i]]);
end;}

function CalculateCRC32(var Buffer;const Size:longword):longword;
asm
push esi
push edi
push ebx

mov edi,edx
mov esi,eax
xor ebx,ebx
xor eax,eax

mov ecx,edi
shr ecx,2
jecxz @Rest

@Loop:
mov edx,[esi]

mov bl,al
xor bl,dl
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

mov bl,al
xor bl,dh
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

shr edx,16

mov bl,al
xor bl,dl
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

mov bl,al
xor bl,dh
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

add esi,4

loop @Loop

@Rest:
mov ecx,edi
and ecx,3
jecxz @End

mov bl,al
xor bl,[esi]
shr eax,8
inc esi
xor eax,dword ptr [CRC32table+ebx*4]
loop @Loop

@End:

pop ebx
pop edi
pop esi
end;

{function CalculateCRC32Masked(var buffer;const size:longword):longword;
var i:integer;
data:tdata absolute buffer;
begin
result:=$ffffffff;
for i:=0 to size-1 do result:=(result shr 8) xor (CRC32Table[byte(result) xor data[i]]);
result:=result xor $ffffffff;
end;}

function CalculateCRC32Masked(var Buffer;const Size:longword):longword;
asm
push esi
push edi
push ebx

mov edi,edx
mov esi,eax
xor ebx,ebx
mov eax,$ffffffff

mov ecx,edi
shr ecx,2
jecxz @Rest

@Loop:
mov edx,[esi]

mov bl,al
xor bl,dl
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

mov bl,al
xor bl,dh
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

shr edx,16

mov bl,al
xor bl,dl
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

mov bl,al
xor bl,dh
shr eax,8
xor eax,dword ptr [CRC32table+ebx*4]

add esi,4

loop @Loop

@Rest:
mov ecx,edi
and ecx,3
jecxz @End

mov bl,al
xor bl,[esi]
shr eax,8
inc esi
xor eax,dword ptr [CRC32table+ebx*4]
loop @Loop

@End:

xor eax,$ffffffff

pop ebx
pop edi
pop esi
end;

var s:string;
x:cardinal;

procedure test;
const Size=128*1024*1024;
var data:array of byte;
i:cardinal;
d:tdatetime;
begin
setlength(data,size);
for i:=0 to size-1 do data[i]:=i;
d:=now;
x:=CalculateCRC32(data[0],Size);
s:=formatdatetime("hh:nn:ss;zzz",now-d);
end;

begin
test;
end.

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