#!/usr/local/bin/perl

# make_huffman.pl
# Creates the huffman JAPH proggie

$s = 'print"Just Another Perl Hacker.\n";';
#$s = 'abcde';

print "\nEncoding:\n'$s'\n\n";

$l = unpack("H*",$s);
print unpack("B*",$s);
print "\n\n$l\n\n";
@n = split(/ */,$l);

# Find the frequencies
foreach $i (@n)
{
  $freq{$i}++;
}

# Create the table
foreach $f (sort keys %freq)
{
#  print "$f - $freq{$f}\n";
  $t[$#t+1] = [$freq{$f},$f];
}

while($#t > 0)
{
  @t = map {$_->[1]}
       sort {$b->[0] <=> $a->[0]}
       map {[$_->[0], $_]} @t;
  $a = pop @t;
  $b = pop @t;
  $c = $a->[0]+$b->[0];
  $d = [$c,[$a->[1],$b->[1]]];
  push @t,$d;
}

sub get_table
{
  my $t = shift;
  my $s = shift;
  my $l,$r;
  if(ref($t))
  {
    $l = get_table($t->[0],$s.'0',$d+1);
    $r = get_table($t->[1],$s.'1',$d+1);
    return "[$l,$r]";
  } else {
    $huff{$t} = $s;
    return $t;
  }
}

$htbl = get_table($t[0]->[1]);

print "Encoding Table:\n";

foreach $a (sort keys %huff)
{
  print "$a -> $huff{$a}\n";
}



for $i (0..$#n)
{
  $enc .= $huff{$n[$i]};
}


@n = split(/(......)/,$enc);


for $i (0..@n)
{
  $new_l .= pack("B*",'00'.$n[$i]) if $i%2;
}


print "\nEncoded String:\n'$new_l'\n",length $new_l;


@tmp = unpack("C*",$new_l);
for$t(@tmp){print "$t\t",$t^8,"\n"}

print unpack("B*",$new_l),"\n";

print "\n$htbl\n";

$dec = (eval $htbl);
$c = $dec;
@l = split(/ */,unpack("B*",$new_l));
for$i(0..$#l)
{
  if($i%8>1)
  {
    print $l[$i];
    if($l[$i]){$c=$c->[1]}else{$c=$c->[0]}
    unless(ref($c)){$o.=$c;$c=$dec}
  }

}

print "-->\n$o\n\n";

print "'",pack("H*",$o),"'\n";

eval(pack("H*",$o));


print <<"ENDPRINT";
-----------------------------
\$dec=eval'$htbl'
;\$c=\$dec;\@l=split(/ */,unpack("B*",'$new_l'));for\$i(
0..\$#l){if(\$i%8){print\$l[\$i];if(\$l[\$i]){\$c=\$c->[1]}else{\$c=\$c->[0]}
unless(ref(\$c)){\$o.=\$c;\$c=\$dec}}}eval(pack("H*",\$o))
ENDPRINT