# stolen at http://www.perlmonks.org/index.pl?node_id=115928
      # as well as the get and escapeHTML functions
    # get options and file contents as array refs
   my $old = get($old_file, 1, 1);
   my $new = get($file, 1, 1);

    open (SDIFF, "> $result_file") || &Error("Can't open $result_file: $!");
   # print out the colour coded diff - common code is black
   # code in $old_file but not $new_file is (bg) red
   # code in $new_file but not $old_file is (bg) green
    print SDIFF "<div><table align=center bgcolor=white celpadding=0 cellspacing=0><tr><th>Color Key:</th></tr>";
    print SDIFF "<tr><td bgcolor=lightcoral>".escapeHTML($old_file)."</td></tr>";
    print SDIFF "<tr><td bgcolor=darkseagreen>".escapeHTML($file)."</td></tr>\n";
    print SDIFF "</table><br><table celpadding=0 cellspacing=0>";

    my $a;
    my $b;
    my $a_lines;
    my $b_lines;
    traverse_sequences({ 
			   MATCH     => sub 
			       { 
				   if ($a)
				   {
				       if ($b)
				       {
					   #$b_lines to compare with $a_lines
					   # print a_lines with hilited diffs
					    print SDIFF "<tr><td bgcolor=lightcoral>"; 
					    my @a_table=split(/ */, $a_lines);
					    my @b_table=split(/ */, $b_lines);
					    traverse_sequences(
						  { 
						      MATCH     => sub { print SDIFF escapeHTML($a_table[$_[0]]) },
						      DISCARD_A => sub { print SDIFF "<span style=\"background-color:yellow\">" . escapeHTML($a_table[$_[0]])."</span>"}, 
						      DISCARD_B => sub { print SDIFF "" },
						  }, 
						  \@a_table, \@b_table,);
					    print SDIFF "</td></tr>";
					    # now print b_lines with hilited diffs
					    print SDIFF "<tr><td bgcolor=darkseagreen>";
					    traverse_sequences(
						  { 
						      MATCH     => sub { print SDIFF escapeHTML($b_table[$_[1]]) },
						      DISCARD_A => sub { print SDIFF ""}, 
						      DISCARD_B => sub { print SDIFF "<span style=\"background-color:yellow\">" . escapeHTML($b_table[$_[1]])."</span>" },
						  }, 
						  \@a_table, \@b_table,);
					    print SDIFF "</td></tr>";
					    $b=0;
					    $b_lines="";
				       }
				       else
				       {
					   print SDIFF "<tr><td bgcolor=lightcoral>".escapeHTML($a_lines)."</td></tr>";
				       }
				       $a=0;
				       $a_lines="";
				   }
				   else
				   {
				       if ($b)
				       {
					   print SDIFF "<tr><td bgcolor=darkseagreen>".escapeHTML($b_lines)."</td></tr>";
					   $b=0;
					   $b_lines="";
				       }
				   }
				   print SDIFF "<tr><td bgcolor=white>".escapeHTML($old->[$_[0]])."</td></tr>" 
			       },
			   DISCARD_A => sub { 
			       $a++;
			       $a_lines.=$old->[$_[0]];
			                    },	   		       
		       DISCARD_B => sub { 
			   $b++;
			   $b_lines.=$new->[$_[1]];
		       }}, $old, $new, );

    print SDIFF "</table>\n";
    close SDIFF;
    last if $caught_sigint;
}