#!/usr/bin/perl

use MIME::Base64;
use Math::Base36 ':all';

my $value = 64000;
print "$value MIME::Base64-> ";
my $encoded = encode_base64($value);
chomp($encoded);
print $encoded;
my $decoded = decode_base64($encoded);
print " back-> $decoded\n";

print "$value Math::Base36-> ";
$encoded = encode_base36($value);
print $encoded;
$decoded = decode_base36($encoded);
print " back-> $decoded\n";

print "$value Math::Base62-> ";
$encoded = Math::Base62::encode_base62($value);
print $encoded;
$decoded = Math::Base62::decode_base62($encoded);
print " back-> $decoded\n";



package Math::Base62;

use warnings;
use strict;

sub encode_base62 {
	return alphaID(shift);
}

sub decode_base62 {
	return alphaID(shift,1);
}

## port of: https://raw.github.com/kvz/kvzlib/master/php/functions/alphaID.inc.php
sub alphaID {
	my ($in, $to_num, $pad_up, $passKey) = @_;

	my $index = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

#	if($passKey) {
		# Although this function's purpose is to just make the
		# ID short - and not so much secure,
		# with this patch by Simon Franz (http://blog.snaky.org/)
		# you can optionally supply a password to make it harder
		# to calculate the corresponding numeric ID

#		for(my $n = 0; $n<length($index); $n++) {
#			$i[$n] = substr($index,$n,1);
#		}

#		$passhash = hash('sha256',$passKey);
#		$passhash = (strlen($passhash) < strlen($index))
#			? hash('sha512',$passKey)
#			: $passhash;

#		for ($n=0; $n < strlen($index); $n++) {
#			$p[] =  substr($passhash, $n ,1);
#		}

#		array_multisort($p,  SORT_DESC, $i);
#		$index = implode($i);
#	}

	my $base  = length($index);
	my $out;

	if($to_num) {
		# Digital number  <<--  alphabet letter code
		$in  = reverse($in);
		$out = 0;
		my $len = length($in) - 1;
		for(my $t = 0; $t <= $len; $t++) {
			my $bcpow = $base**($len - $t);
			$out   = $out + index($index, substr($in, $t, 1)) * $bcpow;
		}

#		if($pad_up =~ /\d+/) {
#			$pad_up--;
#			if ($pad_up > 0) {
#				$out -= pow($base, $pad_up);
#			}
#		}
		$out = sprintf('%F', $out);
		$out = substr($out, 0, index($out, '.'));
	} else {
		# Digital number  -->>  alphabet letter code
#		if (is_numeric($pad_up)) {
#			$pad_up--;
#			if ($pad_up > 0) {
#				$in += pow($base, $pad_up);
#			}
#		}

		$out = '';
		for(my $t = int( log($in)/log($base) ); $t >= 0; $t--) {
			my $bcp = $base**$t;
			my $a   = int($in / $bcp) % $base;
			$out = $out . substr($index, $a, 1);
			$in  = $in - ($a * $bcp);
		}
		$out = reverse($out);
	}

	return $out;
}