#!/usr/bin/perl
#
#  Copyright (C) 2007 by Antonio "s4tan" Parata - s4tan@ictsc.it
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#

use strict;
use warnings;

if ($#ARGV < 0) {
	usage();
}

my $len = length($ARGV[0]); # lunghezza della stringa di ingresso
my @chars = split '', $ARGV[0]; # array dei caratteri in ingresso

my @output = ();
my %encodeMap = &buildAsciiMap; # creo la mappa dei valori codati

encodeString(1,'',@chars); # il carattere lo codifico
encodeString(0,'',@chars); # il primo carattere non lo codifico

for(my $i=0; $i<=$#output;$i++) {
	print $output[$i]."\n";
}


### Start routine

# Effettua la codifica della parola
sub encodeString {	

	my ($mustEncode,$currentEncodedString,@input) = @_;

	if ($#input == 0) {
		# Condizione di terminazione
		# sono all'ultimo carattere, non devo piu' ricorrere :)

		if ($mustEncode) {
			push @output, $currentEncodedString.encode($input[0]);
		}
		else {
			push @output, $currentEncodedString.$input[0];
		}
	}
	else {
	
		my $char = $input[0];
	
		if ($mustEncode) {
			$char = encode($input[0]);
		}

		encodeString(1,$currentEncodedString.$char,@input[1..$#input]);
		encodeString(0,$currentEncodedString.$char,@input[1..$#input]);
	}
}

# Crea la mappa dei valori codificati della tabella ascii
sub buildAsciiMap {
	my %map;	

	for (my $i=0; $i<=255; $i++) {
		$map{chr($i)} = "%".sprintf "%x", $i;
	}

	return %map;
}


# Effettua la codifica del carattere
sub encode {

	my ($char) = @_;
	
	return $encodeMap{$char};
	
}

sub usage {
	print "\n usage: $0  \"word to encode\"\n\n";
	exit 1;
}