#!/usr/bin/perl

# VHDL Obfuscation
# Dave Stevens
# http://iDav.eS/Other-Projects/VHDL-obfuscator/

use POSIX;

if($#ARGV < 0)
{
    print<<ERROR;
You did not pass any arguments.
*required
-indir=<dir>   - directory of input files
-outdir=<dir>  - directory to output to
*optional
-l=<number>    - length of strings
-k=<file>      - file of words to not obfuscate
-h=<file>      - file of previous hashes
ERROR
exit(0);
}


srand(1234567);
$extension = "vhd";
$str_len = 32;
$keyword_file = "";
$hash_file = "";

foreach $arg (@ARGV)
{
	if($arg =~ /-l=(\d+)/)
	{
	    $str_len = $1;
	}
	elsif($arg =~ /\-indir=(\/?((\w+)\/?)+)/i)
	{
		if($arg =~ /\/$/)
		{
			chop($arg);
		}	
		($none, $indir) = split(/=/, $arg);
		push @files, <$indir/*.$extension>;
	}
	elsif($arg =~ /\-outdir=(\/?((\w+)\/?)+)/i)
	{
		if($arg =~ /\/$/)
		{
			chop($arg);
		}
		($none, $outdir) = split(/=/, $arg);
	}
	elsif($arg =~ /-k=(.+)/)
	{
	    $keyword_file = $1;
	}
	elsif($arg =~ /-h=(.+)/)
	{
	    $hash_file = $1;
	}
}

if($outdir eq "")
{
	print "You haven't specified an Output Directory, please use the parameter -outdir=<dir>\n";
	exit(0);
}
if($indir eq "")
{
	print "You haven't specified an Input Directory, please use the parameter -indir=<dir>\n";
	exit(0);
}

if($#files < 0)
{
	print "No Files Found: $indir\n";
	exit(0);
}

print "SETTINGS------------------------\n";
print "INDIR:   $indir\n";
print "OUTDIR:  $outdir\n";
print "KEYWORD: $keyword_file\n";
print "HASH:    $hash_file\n";
print "LENGTH:  $str_len\n\n";

# if out directory does not exist
if(!(-d($outdir)))
{
	system("mkdir $outdir");
}

&setup_delims("/,>=\"-#+)':<&*(.;| 	");
&setup_keywords("left|right|is|file|entity|reject|e|constant|sll|linkage|severity|rem|access|open|group|impure|else|inout|configuration|case|generate|out|of|body|ror|bus|disconnect|others|for|next|sra|xnor|library|function|downto|begin|rol|attribute|block|x|on|register|nand|array|postponed|alias|use|report|buffer|guarded|package|not|xor|map|signal|if|loop|exit|to|subtype|nor|sla|all|component|until|end|b|and|pure|generic|abs|assert|srl|select|or|new|null|variable|label|unaffected|literal|when|procedure|record|units|process|inertial|return|then|architecture|transport|port|while|o|shr|shl|high|low|range|elsif|mod|type|shared|in|with|wait|after|integer|std_logic|std_logic_vector|ieee|work|std_logic_1164|std_logic_arith|std_logic_unsigned|std_logic_signed|numeric_std|signed|unsigned|std|textio|time|ns|ms|conv_std_logic_vector|natural|range|warning|failure|false|boolean|conv_integer|rising_edge|falling_edge|true|note|error|foreign|event|string");

# pull in the hashed file and the keyword file here!
if($hash_file ne "")
{
    # check if file exists
    if(-e($hash_file))
    {
	open HASH_FILE, "< $hash_file" or die "Could not open file: $hash_file ($!)\n";
	while( <HASH_FILE> )
	{
	    chomp();
	    ($string, $word) = split(/ => /);
	    if(defined($string))
	    {
		$hash_inp_str{lc($word)} = $string;
		$hash_str_inp{$string} = lc($word);
	    }
	}
	close HASH_FILE;
    }
    else
    {
	print "The hash file you specified: $hash_file does not exist\n";
	exit(0);
    }
}

if($keyword_file ne "")
{
    # check if file exists
    if(-e($keyword_file))
    {
	open KEYWORD_FILE, "<$keyword_file" or die "Could not open file: $keyword_file ($!)\n";
	while( <KEYWORD_FILE> )
	{
	    chomp();
	    $keywords{lc($_)} = 1;
	}
	close KEYWORD_FILE;
    }
    else
    {
	print "The keyword file you specified: $keyword_file does not exist\n";
	exit(0);
    }
}

foreach $file (@files)
{
	print "FILE: $file\n";
	$reached_code = 0;
	
	open FILE, "< $file" or die "Could not open: $file : $!\n";
	@file2 = split(/\//, $file);
	open FILE_OUT, "> $outdir/$file2[$#file2]"  or die "Could not open file: $outdir/$file2[$#file2] : $!\n";
	while( <FILE> )
	{
	    $linez = "";
	    chomp();
		($code, $comment) = split(/--/);
		$code =~ s/^\s*//;
		$code =~ s/\s*$//;
# check for pragmas
	    if($comment =~ /pragma/)
	    {
		$linez .= "NEWLINE--$comment";
		$linez .= "NEWLINE";
	    }
		if((defined($code)) && ($code ne ""))
		{
			$reached_code = 1;
			&token(lc($code));
		}
		if($reached_code != 1)
		{
		    $linez .= "$_";
		    $linez .= "NEWLINE";
		}

	    # need to get rid of spaces here
	    $linez =~ s/\s+/ /g;
	    $linez =~ s/NEWLINE/\n/g;
	    @linez = split(//, $linez);
	    for($count_it=0;$count_it<=$#linez;$count_it++)
	    {
		if(($linez[$count_it] eq " ") && (($delim{$linez[$count_it+1]}) || ($delim{$linez[$count_it-1]})))
		{

		}
		else
		{
		    print FILE_OUT $linez[$count_it];
		}
	    }
	}
	close FILE_OUT;
	close FILE;
}

open HASH, "> $outdir/hashed.txt" or die;
foreach $key (%hash_inp_str)
{
    if($hash_inp_str{$key} ne "")
    {
	print HASH "$hash_inp_str{$key} => $key\n";
    }
}
close HASH;

exit(0);

sub token()
{
	$line = $_[0];
	$line .= " ";

	@line = split(//, $line);

	$starting = 0;
	for($i=0;$i<=$#line;$i++)
	{
		$what .= $line[$i];
		foreach $key (@delim)
		{
			if($line[$i] =~ /$key/)
			{
				$test = chop($what);
				if($delim{$test} == 1)
				{
				    if($test =~ /\t/)
				    {
					$need_to_add_on = " ";
				    }
				    else
				    {
					$need_to_add_on = $test;
				    }
				}
				else
				{
					$what .= $test;
				}

				if(($keywords{$what} == 1) || ($delim{$what} == 1) || ($what =~ /^[0-9a-fA-F]+$/) || ($need_to_add_on eq "#"))
				{
					@temp = split(//, $what);
					$k = 0;
					for($j=$starting;$j<=$i;$j++)
					{
						$keyw[$j] = $temp[$k];
						$k++;
					}
					if($test ne "")
					{
						$keyw[$j-1] = $need_to_add_on;
						undef($need_to_add_on);
					}
					$starting = $i+1;
					$what = "";
					last;
				}
				else
				{
					@temp = split(//, $what);
					$k = 0;
					for($j=$starting;$j<=$i;$j++)
					{
						$nonkeyw[$j] = $temp[$k];
						$k++;
					}
					if($test ne "")
					{
						$keyw[$j-1] = $need_to_add_on;
						undef($need_to_add_on);
					}
					$starting = $i+1;
					$what = "";
					last;
				}
			}
		}
	}

	$to_hash = "";

	for($i=0;$i<=length($line)-2;$i++)
	{
		if(defined($keyw[$i]))
		{
			if($to_hash ne "")
			{
				$to_hash = &create_random_string($to_hash);
				if($to_hash =~ /^(\d)/)
				{
					$temp = chr(ord($1) + 64);
					$to_hash =~ s/^\d/$temp/;

					$linez .= "$to_hash";
					$temp = "";
				}
				else
				{
					$linez .= "$to_hash";
				}
				$to_hash = "";
			}
			$linez .= "$keyw[$i]";
		}
		else
		{
			$to_hash .= $nonkeyw[$i];
		}
	}
	if($to_hash ne "")
	{
		$to_hash = &create_random_string($to_hash);
		if($to_hash =~ /^(\d)/)
		{
			$temp = chr(ord($1) + 64);
			$to_hash =~ s/^\d/$temp/;

			$linez .= "$to_hash";
			$temp = "";
		}
		else
		{
		    $linez .= "$to_hash";
		}
		$to_hash = "";
	}
	$linez .= " ";

	@keyw = @blank;
	@nonkeyw = @blank;
}


# setup @delim and %delim
sub setup_delims()
{
    @delims = split(//, $_[0]);

    foreach $del (@delims)
    {
	push @delim, "\\$del";
	$delim{$del} = 1;
    }
}

# setup %keywords
sub setup_keywords()
{
    @keywords = split(/\|/, $_[0]);

    foreach $keyz (@keywords)
    {
	$keywords{$keyz} = 1;
    }
}

# create a random string
sub create_random_string()
{
    $inp = $_[0];
    $str = "";

    # if one has already been created then use that
    if(defined($hash_inp_str{$inp}))
    {
	return $hash_inp_str{$inp};
    }

    # create the new string
    for($_i=0;$_i<$str_len;$_i++)
    {
	$temp = int(rand(26+26+10));
	if($temp < 26)
	{
	    $str .= chr($temp + 97);
	}
	elsif(($temp >= 26) && ($temp < 52))
	{
	    $str .= chr($temp - 26 + 65);
	}
	else
	{
	    $str .= chr($temp - 52 + 48);
	}
    }

    # at this point if there are ay clashes they fail out.
    if(defined($hash_str_inp{$str}))
    {
	print "There has been a clash matey!\n";
	exit(0);
    }
    $hash_inp_str{$inp} = $str;
    $hash_str_inp{$str} = $inp;

    return $str;
}