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...calculate the checksum of a file?
Autor: Terry
[ Print tip ]  

Tip Rating (11):  
     


function GetCheckSum(FileName: string): DWORD;
var
  
F: file of DWORD;
  P: Pointer;
  Fsize: DWORD;
  Buffer: array [0..500] of DWORD;
begin
  
FileMode := 0;
  AssignFile(F, FileName);
  Reset(F);
  Seek(F, FileSize(F) div 2);
  Fsize := FileSize(F) - 1 - FilePos(F);
  if Fsize > 500 then Fsize := 500;
  BlockRead(F, Buffer, Fsize);
  Close(F);
  P := @Buffer;
  asm
     
xor eax, eax
     xor ecx, ecx
     mov edi , p
     @again:
       add eax, [edi + 4*ecx]
       inc ecx
       cmp ecx, fsize
     jl @again
     mov @result, eax
   end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  
ShowMessage(IntToStr(GetCheckSum('c:\Autoexec.bat')));
end;


 

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