Lazarus

Using the Lazarus IDE => Designer => Topic started by: fiazhnd on June 13, 2017, 10:17:57 am

Title: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 10:17:57 am

Can someone please explain to me in simple way how i get hex value from a file after open required data like this (a byte, word, Dword and hex value 8 byte long) from Hex offset 0x010 into edit1 and so on.

Title: Re: Get Specific Hex value from Hex file
Post by: Pascal on June 13, 2017, 10:28:26 am

Try SysUtils.Fomat:

Code: Pascal  [Select][+][-]

1. hextringbyte := format('%x', [bytevar]);
2. hexstringword := format('%x', [wordvar]);
3. hexstringdword := format('%x', [dwordvar]);

Title: Re: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 10:31:45 am

But How indicate the offset of hex file?

Title: Re: Get Specific Hex value from Hex file
Post by: Thaddy on June 13, 2017, 10:34:55 am

Quote from: fiazhnd on June 13, 2017, 10:31:45 am

But How indicate the offset of hex file?

Use a filestream...? Sound like homework to me...

Btw: https://www.freepascal.org/docs-html/rtl/classes/bintohex.html

Title: Re: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 10:59:55 am

Boss issue is simple if i know how to use filestream to extract value i wasn't asked at what i want if someone just writes small code to extract value from 0x10. that will be really helpful

Title: Re: Get Specific Hex value from Hex file
Post by: Thaddy on June 13, 2017, 11:05:22 am

Code: Pascal  [Select][+][-]

1. program gotopos;
2. {$mode objfpc}
3. uses classes;
4. var
5.  s:TFilestream;
6. begin
7.  s:=TFilestream.Create('<yourfilename>', fmOpenRead);
8.  try
9.   s.Position := $10;
10.   // whatever;
11.  finally
12.   s.free;
13. end;
14. end.
15.  

But I would write code that tests:
- if the file exists
- if it is indeed bigger than 16 bytes
- etc...

Title: Re: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 02:06:47 pm

Thank you Thaddy i think i am near what i wanted but still materially wrong  :-[

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button5Click(Sender: TObject);
2.  var
3.  filename: string;
4.  s:TFilestream;
5. begin
6.   if openDialog1.Execute then begin
7.     filename := openDialog1.Filename;
8.  s:=TFilestream.Create(filename, fmOpenRead);
9.  try
10.   s.Position := $10;
11.   // whatever;
12.  finally
13.   Edit1.Text:=IntToStr($10);
14.   s.free;
15. end;
16.   end;
17. Closefile(Filename);
18. end;    

Title: Re: Get Specific Hex value from Hex file
Post by: howardpc on June 13, 2017, 03:37:37 pm

You could use something like this

Code: Pascal  [Select][+][-]

1. procedure ShowValuesAtHex10(const aFilename: string; const aMemo: TMemo);
2. var
3.   fs: TFileStream;
4.   q: QWord;
5.   d: DWord absolute q;
6.   w: Word absolute q;
7.   b: Byte absolute q;
8. begin
9.   if FileExists(aFilename) and (FileSize(aFilename) > $20)
10.   and Assigned(aMemo) then begin
11.     fs:=TFilestream.Create(aFilename, fmOpenRead);
12.     try
13.       fs.Position:=$10;
14.       q:=fs.ReadQWord;
15.       aMemo.Clear;
16.       aMemo.Append(Format('Byte:  %x',[b]));
17.       aMemo.Append(Format('Word:  %x',[w]));
18.       aMemo.Append(Format('DWord: %x',[d]));
19.       aMemo.Append(Format('QWord: %x',[q]));
20.     finally
21.       fs.free;
22.     end;
23.   end;
24. end;

called using something like this:

Code: Pascal  [Select][+][-]

1. if OpenDialog1.Execute then
2.     ShowValuesAtHex10(OpenDialog1.FileName, Memo1);

Title: Re: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 05:05:37 pm

Thank you, soo much work like a charm.

Title: Re: Get Specific Hex value from Hex file
Post by: fiazhnd on June 13, 2017, 07:53:53 pm

Mates, can i know why i received value of hex swap B8B479A4B9BF78FF instead of FF78BFB9A479B4B8 in Qword?

Title: Re: Get Specific Hex value from Hex file
Post by: howardpc on June 13, 2017, 08:04:17 pm

Google for endianness, bigendian, littleendian.