Seek bytes and return offset - نسخه قابل چاپ

کد:
{





Protocol.

}



program Project2;



{$APPTYPE CONSOLE}



uses

  Windows;





function CompareMem(P1, P2: Pointer; Length: Integer): Boolean; assembler;

(* ***** BEGIN LICENSE BLOCK *****

 *

 * The function CompareMem is licensed under the CodeGear license terms.

 *

 * The initial developer of the original code is Fastcode

 *

 * Portions created by the initial developer are Copyright (C) 2002-2004

 * the initial developer. All Rights Reserved.

 *

 * Contributor(s): Aleksandr Sharahov

 *

 * ***** END LICENSE BLOCK ***** *

 *************************************************

              Ripped from sysutils

 *************************************************)

asm

   add   eax, ecx

   add   edx, ecx

   xor   ecx, -1

   add   eax, -8

   add   edx, -8

   add   ecx, 9

   push  ebx

   jg    @Dword

   mov   ebx, [eax+ecx]

   cmp   ebx, [edx+ecx]

   jne   @Ret0

   lea   ebx, [eax+ecx]

   add   ecx, 4

   and   ebx, 3

   sub   ecx, ebx

   jg    @Dword

@DwordLoop:

   mov   ebx, [eax+ecx]

   cmp   ebx, [edx+ecx]

   jne   @Ret0

   mov   ebx, [eax+ecx+4]

   cmp   ebx, [edx+ecx+4]

   jne   @Ret0

   add   ecx, 8

   jg    @Dword

   mov   ebx, [eax+ecx]

   cmp   ebx, [edx+ecx]

   jne   @Ret0

   mov   ebx, [eax+ecx+4]

   cmp   ebx, [edx+ecx+4]

   jne   @Ret0

   add   ecx, 8

   jle   @DwordLoop

@Dword:

   cmp   ecx, 4

   jg    @Word

   mov   ebx, [eax+ecx]

   cmp   ebx, [edx+ecx]

   jne   @Ret0

   add   ecx, 4

@Word:

   cmp   ecx, 6

   jg    @Byte

   movzx ebx, word ptr [eax+ecx]

   cmp   bx, [edx+ecx]

   jne   @Ret0

   add   ecx, 2

@Byte:

   cmp   ecx, 7

   jg    @Ret1

   movzx ebx, byte ptr [eax+7]

   cmp   bl, [edx+7]

   jne   @Ret0

@Ret1:

   mov   eax, 1

   pop   ebx

   ret

@Ret0:

        XOR     EAX,EAX

   pop   ebx

end;





const

  HexTbl: array[0..15] of Char = ('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F');



function IntToHex(val: DWORD; minLen: Integer): string;

begin

  Result := '';

  while val<>0 do

  begin

    Result := HexTbl[val and $F] + Result;

    val := val shr 4;

  end;



  while Length(Result)<minLen do

    Result := '0' + Result;

end;



Function SeekBytes (lpFileName :PChar;  lpOldBytes :PByte;  dwLength  :DWORD;

                    dwOffset  :DWORD) :DWORD;

var

  dwFileSize            :DWORD;

  hFile                 :Longword;

  lpBuffer              :PByte;

  dwNumberOfBytesRead   :DWORD;

begin

Result  := 0;

if dwLength = 0 then exit;

  hFile :=  CreateFile(lpFileName,GENERIC_READ, FILE_SHARE_READ, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

    if hFile <> INVALID_HANDLE_VALUE then

    begin

      SetFilePointer(hFile, 0, nil, FILE_BEGIN);

      dwFileSize  :=  GetFileSize(hFile,nil);

      lpBuffer    :=  VirtualAlloc(nil, dwLength, MEM_COMMIT, PAGE_EXECUTE_READWRITE);

      FillChar(lpBuffer^,dwLength,0);

      if lpBuffer <>  nil then

      begin

        dwNumberOfBytesRead := 0;

        Repeat

          SetFilePointer(hFile, dwOffSet, nil, FILE_BEGIN);

          ReadFile(hFile,lpBuffer^,dwLength,dwNumberOfBytesRead,nil);

            if CompareMem(lpBuffer,lpOldBytes,dwLength) = True then

            begin

              Result := dwoffset;

              Break;

            end;

          Inc(dwOffset);

        Until dwOffset >= dwFileSize;

      end;

      VirtualFree(lpBuffer,dwLength,MEM_RELEASE);

    end;

  CloseHandle(hFile);

end;



var

  SearchFor :Array[0..2] of byte = ($00,$00,$00);

  Offset  :DWORD;

begin

  Offset  :=  SeekBytes('C:\server.txt',@(SearchFor),SizeOf(SearchFor), 0);

  Writeln('Offset : ',IntToHex(Offset ,8));

  Readln;



end.