在一个exe文件中查找指定内容，找到则返回起始位置, 否则返回0

function FindString(FileName, FindStr: string): Int64;
var
  FileStream: TFileStream;
  i: Int64;
  Buff: string;
begin
  FileStream := TFileStream.Create(FileName, fmOpenRead);
  SetLength(Buff, FileStream.Size);
  FileStream.Position := 0;
  FileStream.ReadBuffer(PChar(Buff)^, FileStream.Size);
  i := Pos(FindStr, Buff);
  if i > 0 then Result := i-1 else Result := 0;
  FileStream.Destroy;
end;