Plucene::Bitvector - a vector of bits
Index
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NAME
Plucene::Bitvector - a vector of bits
SYNOPSIS
# isa Bit::Vector::Minimal;
my $bitvector = Plucene::Bitvector->read($stream);
$bitvector->write($stream);
my $count = $bitvector->count;
DESCRIPTION
A serialisable implementation of a vector of bits.
This subclass of Bit::Vector::Minimal allows the writing (and reading) of
vectors to (and from) a Plucene stream.
METHODS
count
my $count = $bitvector->count;
Compute the number of one-bits.
write
$bitvector->write($stream);
Write this vector to the passed in stream.
read
my $bitvector = Plucene::Bitvector->read($stream);
Read from the passed in stream.
package Plucene::Bitvector;
use strict;
use warnings;
use base 'Bit::Vector::Minimal';
use List::Util qw(sum);
my @magic = (
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4,
2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4,
2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5,
3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
);
sub count {
sum map $magic[ ord $_ ], split //, shift->{pattern};
}
sub write {
my ($self, $stream) = @_;
$stream->write_int($self->{size});
$stream->write_int($self->count); # Backwards compat.
$stream->print($self->{pattern});
}
sub read {
my ($class, $stream) = @_;
my $size = $stream->read_int;
my $self = $class->new(size => $size, width => 1);
$stream->read_int;
$stream->read($self->{pattern}, 1 + $self->{size} / 8);
return $self;
}
1;