package threads::Q;
use strict; use warnings;
use threads::shared;

our $VERSION = '1.1.5';

sub new {
    my( $package, $size ) = @_;
    my @Q :shared;
    return bless [ \@Q, $size ], $package;
}

sub nq {
    my( $Q, $size ) = @{ shift() };
    lock @$Q;
    for( @_ ) {
        cond_wait @$Q while @$Q > $size;
        push @$Q, $_;
        cond_signal @$Q;
    }
    return;
}

sub dq {
    my( $Q, $size ) = @{ shift() };
    lock @$Q;
    cond_wait @$Q until @$Q;
    cond_signal @$Q;
    shift @$Q
}

sub cq {
    my( $Q, $size ) = @{ shift() };
    scalar @$Q;
}

sub dq_nb {
    my( $Q, $size ) = @{ shift() };
    return unless @$Q;
    lock @$Q;
    shift @$Q;
}