#! /usr/bin/perl

# hexed was written by Dennis Kaptain
# July 2005
# released under GPL available at www.gnu.org/copyleft/gpl.html
# agree to the license or don't use this program.
# There is NO Warranty of any kind on this software
# You agree to use this software AT YOUR OWN RISK.
# If your disk is erased, your data is damaged or lost, 
# your head explodes, your girlfriend leaves you, or you get some
# kind of disease from the use of this software, I won't help you.

# hexed is available for free at http://www.kaptain.us
# Written using Perl 5.8.6 and Tk 804.27-6
# on a Fedora Core 4 system.

# This is intended to be a simple program. It does no error
# checking in this version. There are lots of features that
# can be added in the future. If you have comments, suggestions,
# criticism, advise, dinner invitations, donations, death threats,
# or any other communication you wish to relay, you may do so
# at http://www.kaptain.us/downloads

# Thank you for using this program, I hope you find it useful.

my $version = '1.0';       # Version Number
my $relDate = 'July 2005'; # Release Date

use strict;
use Tk;
use Tk::FileSelect;
use Cwd;


my @bytes;        # store the data
my $numBytes = 0; # size of file
my $pos = 0;      # current position in file
my $file;         # file name
my $openfile;     # the current open file

# gui variables
my $mainWindow;
my $menubar;
my $fileMenu;
my $editMenu;
my $toolMenu;
my $helpMenu;
my $workWindow;
my $workWindowFrame;
my $statFrame;
my $addressLab;
my $addressBox;
my $hexLab;
my $hexBox;
my $hexTag; 
my $dec2hexWin;
my $dec2hexWinFrame;
my $d2hdecLab;
my $d2hdecBox;
my $d2hhexLab;
my $d2hhexBox;
my $aboutWin;

# convert a single ascii char to 2 digit ascii hex representation
sub asc2hex {
   my @hchars = ('0','1','2','3','4','5','6','7','8','9',
                 'A','B','C','D','E','F');
   my $num = ord(@_[0]); # changes char to decimal number
   my $hinib= $hchars[int($num/16)];
   my $lonib= $hchars[($num%16)];
   my $hex = $hinib.$lonib;
   return $hex;
}

#convert a number to a 16 bit hex string
sub addr2hex {
   my @hchars = ('0','1','2','3','4','5','6','7','8','9',
                 'A','B','C','D','E','F');
   my $num = @_[0];
   my $char;
   my $hex = "";

   for (my $x=0; $x<16; $x++) {
      $char = $hchars[$num%16];
      $num = int($num/16);
      $hex = $char.$hex;
      $x++;
   }
   return $hex;
}

# user tool for conversions
sub dec2hex {
   $dec2hexWin = $mainWindow->Toplevel;
   $dec2hexWinFrame = $dec2hexWin->Frame->pack;
   $d2hdecLab = $dec2hexWinFrame->Label('-text'=>'Decimal')->pack('-side'=>'left');
   $d2hdecBox = $dec2hexWinFrame->Entry('-width'=>'8')->pack('-side'=>'left');
   $d2hhexLab = $dec2hexWinFrame->Label('-text'=>'Hex')->pack('-side'=>'left');
   $d2hhexBox = $dec2hexWinFrame->Entry('-width'=>'8')->pack('-side'=>'left');
   $dec2hexWin->Button('-text'=>"Close", 
              '-command'=>[sub{$dec2hexWin->destroy;}]
              )->pack('-side'=>'bottom', '-padx'=>'10');
   $dec2hexWin->Button('-text'=>"Calculate", 
              '-command'=>[\&dec2hexCalc]
              )->pack('-side'=>'bottom', '-padx'=>'10');
   $d2hdecBox->insert('0','0');

}

# about box
sub about {
   $aboutWin = $mainWindow->Toplevel;
   my $aboutFrame = $aboutWin->Frame->pack;
   my $aboutLab = $aboutFrame->Label('-text'=>"hexed, a hex editor
Written by Dennis Kaptain
available at http://www.kaptain.us
$relDate
Version $version
Released without warranty of any kind under GPL. 
Please read the license agreement which is available at:
http://www.gnu.org/copyleft/gpl.html
See the source code for more.
")->pack('-side'=>'left');
   $aboutWin->Button('-text'=>"Close", 
              '-command'=>[sub{$aboutWin->destroy;}]
              )->pack('-side'=>'bottom', '-padx'=>'10');
}

# one byte decimal to hex
sub dec2hexCalc {
   my @hchars = ('0','1','2','3','4','5','6','7','8','9',
                 'A','B','C','D','E','F');
   my $num = $d2hdecBox->get();
   my $hinib= $hchars[int($num/16)];
   my $lonib= $hchars[($num%16)];
   my $hex = $hinib.$lonib;
   $d2hhexBox->delete('0','end');
   if ($num > 255 || $num < 0) {
      $d2hhexBox->insert('0','Error');
   } else {
      $d2hhexBox->insert('0',$hex);
   }
}

# read a file byte by byte into @bytes[$numBytes]
sub readfile {
   $numBytes =0;
   $file = @_[0];
   open(FILE,"<$file");
   while (read(FILE, $bytes[$numBytes], 1)) {
      $numBytes++;
   }
   close(FILE);
}

# change a byte at pos
sub changeByte {
   $bytes[$pos] = chr(hex($hexBox->get()));
   redraw();
}

# redraw the screen with all the data
sub redraw {
   $workWindow->configure("-state"=>"normal");
   my $addr = 0;
   my $addrhex;
   my $row = 1;
   my $ctr = 0;
   my $hexnum;
   $addressBox->delete('0','end');
   $hexBox->delete('0','end');
   $workWindow->delete('1.0','end');
   while ($ctr < $numBytes-1) {
      # print the address
      $addrhex = addr2hex($addr);
      $addressBox->insert('0',$addrhex);
      $workWindow->insert("$row.end","$addrhex  ");
      # print the hex codes for 8 bytes
      for (my $x=0; $x<8; $x++) {
         if ($ctr <= $numBytes) { # dont continue past the end of file
            $hexnum = asc2hex($bytes[$ctr]); 
            $workWindow->insert("$row.end","$hexnum ");
         } else {
            $workWindow->insert("$row.end","   ");
         }
         $ctr++;
      }
      # print the ascii
      $workWindow->insert("$row.end"," ");
      $ctr-=8;
      for (my $x=0; $x<8; $x++) {
         if ($ctr <= $numBytes) { # dont continue past the end of file
            if(ord($bytes[$ctr]) > 31) {
               $workWindow->insert("$row.end","$bytes[$ctr]");
            } else {
               $workWindow->insert("$row.end",chr(20));
            }
         }
         $ctr++;
      }
      
      # next row...
      $workWindow->insert("$row.end","\n");
      $row++;
      $addr+=8;
   }
   # update the status boxes
   $addrhex = addr2hex($pos);
   $addressBox->insert('0',$addrhex);
   $hexBox->insert('0',asc2hex($bytes[$pos]));
   # where to put the tags based on $pos
   # initial settings are for $pos=0
   my $r = 1;   # which row
   my $c1 = 10; # start tag position for the hex code
   my $c2 = 12; # end   tag position for the hex code
   my $c3 = 35; # start tag position for the ascii code
   my $c4 = 36; # end   tag position for the ascii code
   
   $r = int($pos/8)+1;
   $c1 = ($pos%8) * 3 + 10;
   $c2 = $c1 + 2;
   $c3 = ($pos%8) + 35;
   $c4 = $c3 + 1;
   $workWindow->tagAdd('hexTag',"$r.$c1","$r.$c2",); # create a tag
   $workWindow->tagConfigure('hexTag','-background'=>'yellow',); # create a tag
   $workWindow->tagAdd('decTag',"$r.$c3","$r.$c4",); # create a tag
   $workWindow->tagConfigure('decTag','-background'=>'yellow',); # create a tag
   $workWindow->see("$r.$c1"); # make pos visible in the window
   #$workWindow->configure("-state"=>"disabled");
}

# catch arrow key presses and mouse clicks for navigation
sub leftArrowPress {
   if ($pos > 0){
      $pos--;
      redraw;
   }
}
sub rightArrowPress {
   if ($pos < $numBytes){
      $pos++;
      redraw;
   }
}
sub upArrowPress {
   if ($pos -8 > 0){
      $pos-=8;
      redraw;
   } else {
      leftArrowPress;
   }
}
sub downArrowPress {
   if ($pos < $numBytes + 8){
      $pos+=8;
      redraw;
   } else {
      rightArrowPress;
   }
}
sub mouseLeftPress {
   my $lineDotChar;
   my $dot = 0;
   my $line = 1;
   my $colm = 0;
   my $colmStart = 10;
   my $colmEnd = 0;
   my $char = 0;
   my $ind1 = "";
   my $ind2 = "";
   my $ind3 = "";
   my $ind4 = "";
   my $tmp;
   my $addrhex = 0;
   #where did I get clicked?
   $lineDotChar=$workWindow->index('current');
   chomp $lineDotChar;
   $dot = rindex($lineDotChar,'.');
   $line = substr($lineDotChar,0,$dot);
   $colm = substr($lineDotChar,$dot+1);
   # find the file postion
   # which of 8 chars on that line is it?
   if ($colm > 9  ) { $char = 0; $colmStart = 10 }
   if ($colm > 12 ) { $char = 1; $colmStart = 13 }
   if ($colm > 15 ) { $char = 2; $colmStart = 16 }
   if ($colm > 18 ) { $char = 3; $colmStart = 19 }
   if ($colm > 21 ) { $char = 4; $colmStart = 22 }
   if ($colm > 24 ) { $char = 5; $colmStart = 25 }
   if ($colm > 27 ) { $char = 6; $colmStart = 28 }
   if ($colm > 30 ) { $char = 7; $colmStart = 31 }
   $colmEnd = $colmStart + 2;
   $pos = $char + (($line - 1)  * 8); # got it!
   # fix up the window
   redraw;
}

# Menu Commands
# File -> open
sub openFile {
   my $fs = $workWindow->FileSelect(
              '-directory'=>Cwd::cwd(),
              '-initialfile'=>'',
              '-filter'=>'*.*',
              '-filelabel'=>'File to Open',
              '-filelistlabel'=>'File List',
              '-dirlabel'=>'Directories',
              '-dirlistlabel'=>'Dir List'
              #'-verify'=>[-T], #only text files
              );
   $openfile = $fs->Show;
   readfile("$openfile");
   $pos = 0;
   redraw;
}

# File -> save
sub saveFile {
   $file = $openfile;
   open(FILE,">$file");
   for (my $x =0;$x<$numBytes;$x++) {
      print FILE $bytes[$x];
   }
   close(FILE);
}

# File -> save as
sub saveFileAs {
   my $fs = $workWindow->FileSelect(
              '-directory'=>Cwd::cwd(),
              '-initialfile'=>'',
              '-filter'=>'*.*',
              '-filelabel'=>'File to Open',
              '-filelistlabel'=>'File List',
              '-dirlabel'=>'Directories',
              '-dirlistlabel'=>'Dir List'
              #'-verify'=>[-T], #only text files
              );
   $openfile = $fs->Show;
   saveFile();
}

# File -> close
sub closeFile {
   for (my $x=0; $x < $numBytes; $x++) {
      $bytes[$x]=chr(0);
   }
   $numBytes = 0;
   $#bytes = -1;
   redraw;
}

# File -> exit
sub quitProg {
   exit(0);
}

# Edit -> insert before 
sub editInsBefore {
   for (my $x=$numBytes; $x>$pos-1; $x--) {
      $bytes[$x+1] = $bytes[$x];
   }
   $bytes[$pos] = chr(0);
   $numBytes++;
   redraw;
}

# Edit -> insert after
sub editInsAfter {
   my $x;
   for ($x=$numBytes; $x>$pos; $x--) {
      $bytes[$x+1] = $bytes[$x];
   }
   $bytes[$pos+1] = chr(0);
   $numBytes++;
   redraw;
}

# Edit -> delete
# delete a byte at position $pos
sub editDelByte {
   for (my $x=$pos; $x<$numBytes; $x++) {
      $bytes[$x] = $bytes[$x+1];
   }
   $numBytes--;
   redraw();
}



# #########################
# start the gui
# #########################
$mainWindow = MainWindow->new();
$mainWindow->configure(-title=>"Hex Editor");
$mainWindow->geometry("+100+50"); # where to display on the screen

# menu
$menubar = $mainWindow->Frame;
$menubar->pack('-side'=>'top', '-fill'=>'x');

# File menu and options
$fileMenu = $menubar->Menubutton('-text'=>'File', '-underline'=>'0',
                                 '-tearoff'=>'0')->pack('-side'=>'left');
$fileMenu->command('-label'=>'Open','-underline'=>'0', 
                             '-command'=>[\&openFile]);
$fileMenu->command('-label'=>'Save','-underline'=>'0', 
                             '-command'=>[\&saveFile]);
$fileMenu->command('-label'=>'Save As','-underline'=>'5', 
                             '-command'=>[\&saveFileAs]);
$fileMenu->command('-label'=>'Close','-underline'=>'0', 
                             '-command'=>[\&closeFile]);
$fileMenu->command('-label'=>'Exit','-underline'=>'1', 
                             '-command'=>[\&quitProg]);

# Edit menu and options
$editMenu = $menubar->Menubutton('-text'=>'Edit', '-underline'=>'0',
                                 '-tearoff'=>'0')->pack('-side'=>'left');
$editMenu->command('-label'=>'Insert Before','-underline'=>'7', 
                             '-command'=>[\&editInsBefore]);
$editMenu->command('-label'=>'Insert After','-underline'=>'7', 
                             '-command'=>[\&editInsAfter]);
$editMenu->command('-label'=>'Delete','-underline'=>'0', 
                             '-command'=>[\&editDelByte]);
# Tools menu and options
$toolMenu = $menubar->Menubutton('-text'=>'Tools', '-underline'=>'0',
                             '-tearoff'=>'0')->pack('-side'=>'left');
$toolMenu->command('-label'=>'Dec 2 Hex','-underline'=>'0',
                             '-command'=>[\&dec2hex]);
# Help menu and options
$helpMenu = $menubar->Menubutton('-text'=>'Help', '-underline'=>'0',
                             '-tearoff'=>'0')->pack('-side'=>'left');
$helpMenu->command('-label'=>'About','-underline'=>'0',
                             '-command'=>[\&about]);

# work window
$workWindowFrame = $mainWindow->Frame->pack;
$workWindow = $workWindowFrame->Scrolled('Text','-scrollbars'=>'e',
                    '-wrap'=>'word','-height'=>'10','-width'=>'50'
                    )->pack;
$workWindow->bind('<KeyPress-Right>',\&rightArrowPress);
$workWindow->bind('<KeyPress-Left>',\&leftArrowPress);
$workWindow->bind('<KeyPress-Up>',\&upArrowPress);
$workWindow->bind('<KeyPress-Down>',\&downArrowPress);
$workWindow->bind('<ButtonRelease-1>',\&mouseLeftPress);
$statFrame = $mainWindow->Frame->pack;
$addressLab = $statFrame->Label('-text'=>'Address')->pack('-side'=>'left');
$addressBox = $statFrame->Entry('-width'=>'8')->pack('-side'=>'left');
$hexLab = $statFrame->Label('-text'=>'Hex')->pack('-side'=>'left');
$hexBox = $statFrame->Entry('-width'=>'3')->pack('-side'=>'left');
$statFrame->Button('-text'=>"Change Byte", 
              '-command'=>[\&changeByte]
              )->pack('-side'=>'left','-padx'=>'10');
$statFrame->Button('-text'=>"Exit", 
              '-command'=>[sub{exit(0);}]
              )->pack('-side'=>'bottom','-padx'=>'10');

MainLoop; # run the program. wait for events.