File Coverage

blib/lib/Bijection.pm

Criterion	Covered	Total	%
statement	33	33	100.0
branch	1	2	50.0
condition	6	18	33.3
subroutine	10	10	100.0
pod	3	3	100.0
total	53	66	80.3

package Bijection;
use 5.006; use strict; use warnings; our $VERSION = '0.03';
use Import::Export; use base qw/Import::Export/;
use Carp qw/croak/;
our %EX = (biject => [qw/all/], inverse => [qw/all/], bijection_set => [qw/all/]);

our (@ALPHA, $COUNT, %INDEX);
BEGIN {
	sub bijection_set {
		@ALPHA = @_;
		$COUNT = @ALPHA;
		my $index = -1;
		%INDEX = map +( $_ => ++$index ), @ALPHA;
	}
	bijection_set(qw/b c d f g h j k l m n p q r s t v w x y z B C D F G H J K L M N P Q R S T V W X Y Z 0 1 2 3 4 5 6 7 8 9/);
}

sub biject {
	my ($id, $out) = @_;
	croak "id to encode must be an integer and non-negative" unless (($id =~ m/^\d+$/ || $id > 0) and $id += $COUNT);
	do { $out .= $ALPHA[($id % $COUNT)]; 1} and $id = int($id/$COUNT) while ($id > 0);
	reverse ($out || $ALPHA[0]);
}

sub inverse {
	my ($out, $id) = (@_, 0);
	defined $INDEX{$_} && do { $id = $id * $COUNT + $INDEX{$_}; 1; } or croak "invalid character $_ in $out" for (split //, $out);
	$id - $COUNT;
}

1;

__END__