Programming Forums > Application Development > Delphi

karamellz · May 12th, 2005, 7:26 AM

Hello everyone! Yesterday I was very bored, and came up with the idea to make a module for hex-editing. I made two overloaded procedures for writing to the executable, with either a string or array of byte as input. I also made a procedure that converts a string into array of byte (StrToByte):

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procedure StrToByte(input:string; Out output:array of byte);
var
i:byte;
begin
for i := 1 to Length(input) do
  begin
  output[i-1] := Ord(input[i]);
  end;
end;

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var
   Stream:TFileStream;

.....................

procedure WriteInfo(buffer:array of byte; offset:integer; exepath:string);overload;
begin
Stream := TFileStream.Create(exepath, fmOpenReadWrite);
Stream.Seek(offset, soFromBeginning);
Stream.WriteBuffer(buffer, SizeOf(buffer));
Stream.Free;
end;

procedure WriteInfo(buffer:string; offset:integer; exepath:string);overload;
var
bytes:array of byte;
begin
SetLength(bytes, Length(buffer));
StrToByte(buffer, bytes);
Stream := TFileStream.Create(exepath, fmOpenReadWrite);
Stream.Seek(offset, soFromBeginning);
Stream.WriteBuffer(bytes, SizeOf(bytes));
Stream.Free;
end;

Now my problem is that when I try use the "string"-version of the WriteInfo (1) it writes a bunch of nonsense to the executable. When I instead make the stringconversion in my button and then call the "array"-version of my WriteInfo (2) it works as it should, even tho it does the same in both situations:

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(1)
procedure TForm1.Button2Click(Sender: TObject);
begin
WriteInfo('Testing',$AFAFAF,'TestProg.exe');
end;

(2)
procedure TForm1.Button1Click(Sender: TObject);
var
bytes:array of byte;
begin
SetLength(bytes,7);
StrToByte('Testing', bytes);
WriteInfo(bytes,$AFAFAF,'TestProg.exe');
end;

If anyone knows what is wrong help would be greatly appreciated. Thanks in advance.
Karamellz~

Code Wizard · Jun 24th, 2005, 3:29 AM

I'm not sure, there is several things that seem odd to me. But I've only been working with Delphi 4 & 5, nothing newer.
procedure StrToByte(input:string; Out output:array of byte);
I don't know that way of notation. Is this new? It used to be
procedure StrToByte(input:string; var output:array of byte);

And I think you can not pass "array of" in a "var" argument without defining its own type for it. (type A_O_B=array of byte; var output: A_O_B;).
But if the compiler doesn't complain, they seem to have fixed this.

Try passing "bytes[0]" instead of "bytes" to the Stream.WriteBuffer() method. IIRC Pascal handles arrays in memory a little different from C.

May 12th, 2005, 7:26 AM	#1
karamellz Newbie Join Date: May 2005 Posts: 2 Rep Power: 0	Hex Editing Module Hello everyone! Yesterday I was very bored, and came up with the idea to make a module for hex-editing. I made two overloaded procedures for writing to the executable, with either a string or array of byte as input. I also made a procedure that converts a string into array of byte (StrToByte): (Toggle Plain Text) procedure StrToByte(input:string; Out output:array of byte); var i:byte; begin for i := 1 to Length(input) do begin output[i-1] := Ord(input[i]); end; end; procedure StrToByte(input:string; Out output:array of byte); var i:byte; begin for i := 1 to Length(input) do begin output[i-1] := Ord(input[i]); end; end; (Toggle Plain Text) var Stream:TFileStream; ..................... procedure WriteInfo(buffer:array of byte; offset:integer; exepath:string);overload; begin Stream := TFileStream.Create(exepath, fmOpenReadWrite); Stream.Seek(offset, soFromBeginning); Stream.WriteBuffer(buffer, SizeOf(buffer)); Stream.Free; end; procedure WriteInfo(buffer:string; offset:integer; exepath:string);overload; var bytes:array of byte; begin SetLength(bytes, Length(buffer)); StrToByte(buffer, bytes); Stream := TFileStream.Create(exepath, fmOpenReadWrite); Stream.Seek(offset, soFromBeginning); Stream.WriteBuffer(bytes, SizeOf(bytes)); Stream.Free; end; var Stream:TFileStream; ..................... procedure WriteInfo(buffer:array of byte; offset:integer; exepath:string);overload; begin Stream := TFileStream.Create(exepath, fmOpenReadWrite); Stream.Seek(offset, soFromBeginning); Stream.WriteBuffer(buffer, SizeOf(buffer)); Stream.Free; end; procedure WriteInfo(buffer:string; offset:integer; exepath:string);overload; var bytes:array of byte; begin SetLength(bytes, Length(buffer)); StrToByte(buffer, bytes); Stream := TFileStream.Create(exepath, fmOpenReadWrite); Stream.Seek(offset, soFromBeginning); Stream.WriteBuffer(bytes, SizeOf(bytes)); Stream.Free; end; Now my problem is that when I try use the "string"-version of the WriteInfo (1) it writes a bunch of nonsense to the executable. When I instead make the stringconversion in my button and then call the "array"-version of my WriteInfo (2) it works as it should, even tho it does the same in both situations: (Toggle Plain Text) (1) procedure TForm1.Button2Click(Sender: TObject); begin WriteInfo('Testing',$AFAFAF,'TestProg.exe'); end; (2) procedure TForm1.Button1Click(Sender: TObject); var bytes:array of byte; begin SetLength(bytes,7); StrToByte('Testing', bytes); WriteInfo(bytes,$AFAFAF,'TestProg.exe'); end; (1) procedure TForm1.Button2Click(Sender: TObject); begin WriteInfo('Testing',$AFAFAF,'TestProg.exe'); end; (2) procedure TForm1.Button1Click(Sender: TObject); var bytes:array of byte; begin SetLength(bytes,7); StrToByte('Testing', bytes); WriteInfo(bytes,$AFAFAF,'TestProg.exe'); end; If anyone knows what is wrong help would be greatly appreciated. Thanks in advance. Karamellz~

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Jun 24th, 2005, 3:29 AM	#2
Code Wizard Newbie Join Date: Jun 2005 Posts: 1 Rep Power: 0	I'm not sure, there is several things that seem odd to me. But I've only been working with Delphi 4 & 5, nothing newer. procedure StrToByte(input:string; Out output:array of byte); I don't know that way of notation. Is this new? It used to be procedure StrToByte(input:string; var* output:array of byte);* And I think you can not pass "array of" in a "var" argument without defining its own type for it. (type A_O_B=array of byte; var output: A_O_B;). But if the compiler doesn't complain, they seem to have fixed this. Try passing "bytes[0]" instead of "bytes" to the Stream.WriteBuffer() method. IIRC Pascal handles arrays in memory a little different from C.

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Programming Forums > Application Development > Delphi

Hex Editing Module