Table:Array[0..255] of DWORD;
procedure MakeTable();
var
i,j,Crc:integer;
begin
for i:=0 to 255 do
begin
Crc:=i;
for j:=0 to 7 do
begin
if (Crc and 1)<>0 then
Crc:=(Crc shr 1) xor $EDB88320
else
Crc:=Crc shr 1;
end;
Table[i]:=Crc;
end;
end;
procedure GetCRC32File(FileName:string;var CRC32:DWORD);
var
F:file;
BytesRead:DWORD;
Buffer:array[1..65521] of Byte;
i:Word;
begin
FileMode :=0;
CRC32 :=$ffffffff;
{$I-}
AssignFile(F,FileName);
Reset(F,1);
if IoResult = 0 then
begin
repeat
BlockRead(F,Buffer,Sizeof(Buffer),BytesRead);
for i := 1 to BytesRead do
CRC32 := (CRC32 shr 8) xor Table[Buffer[i] xor (CRC32 and $000000ff)];
until BytesRead = 0;
end;
CloseFile(F);
{$I+}
CRC32 := not CRC32;
end;
function GetCrc32Str(s: string; Seed: LongInt):string;
var
Count: Integer;
CrcVal: LongInt;
begin
CrcVal := Seed;
for Count := 1 to Length(s) do
CrcVal := Table[Byte(CrcVal xor DWORD(Ord(s[Count])))] xor ((CrcVal shr 8) and $00FFFFFF);
Result := IntToHex(not(CrcVal), 8);
end;
调用：
procedure TForm1.Button1Click(Sender: TObject);
begin
MakeTable();
Edit1.Text:=GetCrc32Str('11111111',8);//这里取指定字符串的CRC32校验值;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
FileStr:String;
crc: DWORD;
begin
MakeTable();
FileStr:=Application.ExeName;//这里取指定的文件的crc32校验值;
GetCRC32File(FileStr,crc);
if crc<>0 then
Edit2.Text:=PChar(IntToHex(crc,6));
end;