[font="Courier New"][b]function [/b]ScanFile([b]const [/b]FileName: [b]string[/b];
  [b]const [/b]forString: [b]string[/b];
  caseSensitive: Boolean): Longint;
[/font][font="Courier New"][b]const
  [/b]BufferSize = $8001;  [/font][font="Courier New"][color="#000080"][i]{ 32K+1 bytes }
[/i][/color][/font][font="Courier New"][b]var
  [/b]pBuf, pEnd, pScan, pPos: PChar;
  filesize: LongInt;
  bytesRemaining: LongInt;
  bytesToRead: Integer;
  F: [b]file[/b];
  SearchFor: PChar;
  oldMode: Word;
[/font][b][font="Courier New"]begin
  [/font][/b][font="Courier New"][color="#000080"][i]{ assume failure }
  [/i][/color]Result := -1;
  [b]if [/b](Length(forString) = 0) [b]or [/b](Length(FileName) = 0) [b]then [/b]Exit;
  SearchFor := [b]nil[/b];
  pBuf      := [b]nil[/b];
  [/font][font="Courier New"][color="#000080"][i]{ open file as binary, 1 byte recordsize }
  [/i][/color]AssignFile(F, FileName);
  oldMode  := FileMode;
  FileMode := 0;    [/font][font="Courier New"][color="#000080"][i]{ read-only access }
  [/i][/color]Reset(F, 1);
  FileMode := oldMode;
  [b]try [/b][/font][font="Courier New"][color="#000080"][i]{ allocate memory for buffer and pchar search string }
    [/i][/color]SearchFor := StrAlloc(Length(forString) + 1);
    StrPCopy(SearchFor, forString);
    [b]if not [/b]caseSensitive [b]then  [/b][/font][font="Courier New"][color="#000080"][i]{ convert to upper case }
      [/i][/color]AnsiUpper(SearchFor);
    GetMem(pBuf, BufferSize);
    filesize       := System.Filesize(F);
    bytesRemaining := filesize;
    pPos           := [b]nil[/b];
    [b]while [/b]bytesRemaining > 0 [/font][b][font="Courier New"]do
    begin
      [/font][/b][font="Courier New"][color="#000080"][i]{ calc how many bytes to read this round }
      [/i][/color][b]if [/b]bytesRemaining >= BufferSize [/font][font="Courier New"][b]then
        [/b]bytesToRead := Pred(BufferSize)
      [/font][font="Courier New"][b]else
        [/b]bytesToRead := bytesRemaining;
      [/font][font="Courier New"][color="#000080"][i]{ read a buffer full and zero-terminate the buffer }
      [/i][/color]BlockRead(F, pBuf^, bytesToRead, bytesToRead);
      pEnd  := @pBuf[bytesToRead];
      pEnd^ := #0;
      pScan := pBuf;
      [b]while [/b]pScan < pEnd [/font][font="Courier New"][b]do
      begin
        if not [/b]caseSensitive [b]then [/b][/font][font="Courier New"][color="#000080"][i]{ convert to upper case }
          [/i][/color]AnsiUpper(pScan);
        pPos := StrPos(pScan, SearchFor);  [/font][font="Courier New"][color="#000080"][i]{ search for substring }
        [/i][/color][b]if [/b]pPos <> [/font][b][font="Courier New"]nil then
        begin [/font][/b][font="Courier New"][color="#000080"][i]{ Found it! }
          [/i][/color]Result := FileSize - bytesRemaining +
            Longint(pPos) - Longint(pBuf);
          Break;
        [b]end[/b];
        pScan := StrEnd(pScan);
        Inc(pScan);
      [b]end[/b];
      [b]if [/b]pPos <> [b]nil then [/b]Break;
      bytesRemaining := bytesRemaining - bytesToRead;
      [b]if [/b]bytesRemaining > 0 [/font][font="Courier New"][b]then
      begin
        [/b]Seek(F, FilePos(F) - Length(forString));
        bytesRemaining := bytesRemaining + Length(forString);
      [b]end[/b];
    [b]end[/b]; [/font][font="Courier New"][color="#000080"][i]{ While }
  [/i][/color][/font][font="Courier New"][b]finally
    [/b]CloseFile(F);
    [b]if [/b]SearchFor <> [b]nil then [/b]StrDispose(SearchFor);
    [b]if [/b]pBuf <> [b]nil then [/b]FreeMem(pBuf, BufferSize);
  [b]end[/b];
[b]end[/b]; [/font][font="Courier New"][color="#000080"][i]{ ScanFile }


// Search in autoexec.bat for "keyb" with case insensitive
// In der autoexec.bat nach "keyb" suchen

[/i][/color][b]procedure [/b]TForm1.Button1Click(Sender: TObject);
[/font][font="Courier New"][b]var
  [/b]Position: integer;
[/font][font="Courier New"][b]begin
  [/b]Position := ScanFile('c:\autoexec.bat', 'keyb', False);
  ShowMessage(IntToStr(Position));
[b]end[/b];[/font]