File Coverage

blib/lib/Language/Befunge/lib/MODU.pm

Criterion	Covered	Total	%
statement	10	36	27.7
branch	0	8	0.0
condition	0	9	0.0
subroutine	4	7	57.1
pod	4	4	100.0
total	18	64	28.1

#
# This file is part of Language-Befunge
#
# This software is copyright (c) 2003 by Jerome Quelin.
#
# This is free software; you can redistribute it and/or modify it under
# the same terms as the Perl 5 programming language system itself.
#
use strict;
use warnings;

package Language::Befunge::lib::MODU;
# ABSTRACT: Modulo Arithmetic extension
$Language::Befunge::lib::MODU::VERSION = '5.000';
use POSIX qw{ floor };

sub new { return bless {}, shift; }


# -- modulus

#
# $mod = M( $x, $y );
#
# signed-result modulo: x MOD y = x - FLOOR(x / y) * y
#
sub M {
    my ($self, $lbi) = @_;
    my $ip = $lbi->get_curip;
    my $y = $ip->spop;
    my $x = $ip->spop;
    my $mod = $y == 0
        ? 0
        : $x - floor($x/$y)*$y;
    $ip->spush($mod);
}


#
# $mod = U( $x, $y );
#
# Sam Holden's unsigned-result modulo... No idea who this Sam Holden is
# or if he has a special algorithm for this, therefore always returning
# absolute value of standard modulo.
#
sub U {
    my ($self, $lbi) = @_;
    my $ip = $lbi->get_curip;
    my $y = $ip->spop;
    my $x = $ip->spop;
    if ( $y == 0 ) {
        $ip->spush(0);
        return;
    }
    my $mod = $x % $y;
    $ip->spush(abs($mod));
}


#
# $mod = R( $x, $y );
#
# C-language integer remainder: old C leaves negative modulo undefined
# but C99 defines it as the same sign as the dividend so that's what we're
# going with.
#
sub R {
    my ($self, $lbi) = @_;
    my $ip = $lbi->get_curip;
    my $y = $ip->spop;
    my $x = $ip->spop;
    if ( $y == 0 ) {
        $ip->spush(0);
        return;
    }

    my $mod = $x % $y;
    if ( ($x <= 0 && $mod <= 0) || ($x >= 0 && $mod >= 0)) {
        $ip->spush( $mod );
    } else {
        $ip->spush( -$mod );
    }
}


1;

__END__