File Coverage

blib/lib/String/Urandom.pm

Criterion	Covered	Total	%
statement	32	39	82.0
branch	6	14	42.8
condition	4	4	100.0
subroutine	8	8	100.0
pod	4	5	80.0
total	54	70	77.1

#----------------------------------------------------------------------------+
#
#  String::Urandom - An alternative to using /dev/random
#
#  DESCRIPTION
#  Using output of /dev/urandom.  Simply convert bytes into 8-bit characters.
#
#  AUTHOR
#  Marc S. Brooks
#
#  This module is free software; you can redistribute it and/or
#  modify it under the same terms as Perl itself.
#
#----------------------------------------------------------------------------+

package String::Urandom;

use strict;
use warnings;
use Params::Validate qw( :all );

our $VERSION = 0.16;

#~~~~~~~~~~~~~~~~~~~~~~~~~~[  OBJECT METHODS  ]~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~#

#----------------------------------------------------------------------------+
# new(\%params)
#
# General object constructor.

sub new {
    my $class  = shift;
    my $params = (ref $_[0] eq 'HASH') ? shift : { @_ };
    return bless( {
        LENGTH => $params->{LENGTH} || 32,
        CHARS  => $params->{CHARS}  ||
                  [ qw/ a b c d e f g h i j k l m n o p q r s t u v w x y z
                        A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
                        1 2 3 4 5 6 7 8 9                                 / ]
    }, $class );
}

#----------------------------------------------------------------------------+
# str_length($value)
#
# Set/Get the string length.

sub str_length {
    my ( $self, $value )
      = validate_pos( @_,
          { type => OBJECT },
          { type => SCALAR, optional => 1 }
          );

    return $self->{LENGTH} unless ($value);
    return $self->{LENGTH} unless ($value =~ /^[\d]*$/);
    $self->{LENGTH} = $value;
    return $self->{LENGTH};
}

#----------------------------------------------------------------------------+
# str_chars($value)
#
# Set/Get the string characters.

sub str_chars {
    my ( $self, $value )
      = validate_pos( @_,
          { type => OBJECT },
          { type => SCALAR, optional => 1 }
          );

    return $self->{CHARS} unless ($value);
    return $self->{CHARS} unless ($value =~ /^[\w\s]*$/);
    my @chars = split(/\s+/, $value);
    $self->{CHARS} = \@chars;
    return $self->{CHARS};
}

#----------------------------------------------------------------------------+
# rand_string()
#
# Generate a new random string.

sub rand_string {
    my ($self)
      = validate_pos( @_,
          { type => OBJECT }
          );

    my @chars = @{ $self->{CHARS} };

    shuffle_array(\@chars);

    open (DEV, "/dev/urandom") or die "Cannot open file: $!";
    read (DEV, my $bytes, $self->{LENGTH});

    my $string;
    my @randoms = split(//, $bytes);
    foreach (@randoms) {
        $string .= $chars[ ord($_) % @chars ];
    }
    return $string;
}

#----------------------------------------------------------------------------+
# shuffle_array()
#
# Fisher-Yates shuffle algorithm - Perl Cookbook, Recipe 4.17

sub shuffle_array {
    my $array = shift;

    for (my $i = @$array; --$i;) {
        my $j = int rand ($i + 1);
        next if ($i == $j);
        @$array[$i, $j] = @$array[$j, $i];
    }
}

1;

__END__