ch15.066_best_ex15.10

Perl Best Practices the source code

##############################################################################
##   Example 15.10 (Recommended) from Chapter 15 of "Perl Best Practices"   ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


#  Example 15-10. A bit-string class with a more useful interface


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;


package Bit::String;
use Class::Std::Utils;
use Readonly;
{
    Readonly my $EMPTY_STR   => q{};

    Readonly my $BIT_PACKING => 'b*';    # i.e. vec() compatible binary
    Readonly my $BIT_DENSITY => 1;       # i.e. 1 bit/bit
 
    # Attributes...
    my %bitset_of;
 
    sub new {
        # [As in  REF XREF90313_Example_159_ \h Example 15-9  08D0C9EA79F9BACE118C8200AA004BA90B0200000008000000170000005800520045004600390030003300310033005F004500780061006D0070006C0065005F003100350039005F000000 ]
    }
 
    sub get_bit {
        # [As in  REF XREF90313_Example_159_ \h Example 15-9  08D0C9EA79F9BACE118C8200AA004BA90B0200000008000000170000005800520045004600390030003300310033005F004500780061006D0070006C0065005F003100350039005F000000 ]
    }
 
    sub set_bit {
        # [As in  REF XREF90313_Example_159_ \h Example 15-9  08D0C9EA79F9BACE118C8200AA004BA90B0200000008000000170000005800520045004600390030003300310033005F004500780061006D0070006C0065005F003100350039005F000000 ]
    }
 
    # Convenience method to flip individual bits...
    sub flip_bit {
        my ($self, $bitnum) = @_;
 
        vec($bitset_of{it $self}, $bitnum, $BIT_DENSITY)
            = !vec($bitset_of{ident $self}, $bitnum, $BIT_DENSITY);
 
        return;
    }
 
    # Convenience method to provide a string representation of the bits...
    sub as_string {
        my ($self) = @_;
 
        return join $EMPTY_STR, unpack $BIT_PACKING, $bitset_of{ident $self};
    }
}