#!/usr/bin/perl

# Insensitive index/rindex written in Pure Perl
# Coded by Trizen - 05 February 2012
# http://trizen.googlecode.com

use strict;
use warnings;

sub i_index {
    my (@text) = split(//, lc shift(), 0);
    my (@comp) = split(//, lc shift(), 0);

    my $match_length = @comp;
    my @list         = (0 .. $match_length - 1);

    foreach my $i (0 .. $#text) {
        if ($text[$i] eq $comp[0]) {
            my $x = 0;
            foreach my $y (@list) {
                $text[$i + $y] eq $comp[$y] ? ++$x : last;
            }
            return $i if $x == $match_length;
        }
    }
    return -1;
}

sub i_rindex {
    my (@text) = split(//, lc shift(), 0);
    my (@comp) = split(//, lc shift(), 0);

    my $match_length = @comp;
    my @list         = (0 .. $match_length - 1);

    foreach my $i (reverse 0 .. $#text) {
        if ($text[$i] eq $comp[0]) {
            my $x = 0;
            foreach my $y (@list) {
                $text[$i + $y] eq $comp[$y] ? ++$x : last;
            }
            return $i if $x == $match_length;
        }
    }
    return -1;
}

my $string = 'GNU General Public License or the Artistic License';

print substr($string, i_index($string, 'art'), 6);
print substr($string, i_rindex($string, 'IC '), 10);