Cache::File::Heap(3) User Contributed Perl Documentation Cache::File::Heap(3)NAMECache::File::Heap - A file based heap for use by Cache::File
SYNOPSIS
use Cache::File::Heap;
$heap = Cache::File::Heap->new('/path/to/some/heap/file');
$heap->add($key, $val);
($key, $val) = $heap->minimum;
($key, $val) = $heap->extract_minimum;
$heap->delete($key, $val);
DESCRIPTION
This module is a wrapper around a Berkeley DB using a btree structure
to implement a heap. It is specifically for use by Cache::File for
storing expiry times (although with a bit of work it could be made more
general).
See LIMITATIONS below.
CONSTRUCTOR
my $heap = Cache::File::Heap->new( [$dbfile] );
The heap constructor takes an optional argument which is the name of
the database file to open. If specified, it will attempt to open the
database during construction. A new Cache::File::Heap blessed
reference will be returned, or undef if the open failed.
METHODS
$h->open($dbfile)
Opens the specified database file.
$h->close()
Closes a previously opened heap database. Note that the database
will be automatically closed when the heap reference is destroyed.
$h->add($key, $val)
Adds a key and value pair to the heap. Currently the key should be
a number, whilst the value may be any scalar. Invokes 'die' on
failure (use eval to catch it).
$h->delete($key, $val)
Removes a key and value pair from the heap. Returns 1 if the pair
was found and removed, or 0 otherwise.
($key, $val) = $h->minimum()
In list context, returns the smallest key and value pair from the
heap. In scalar context only the key is returned. Note smallest
is defined via a numerical comparison (hence keys should always be
numbers).
($key, $vals) = $h->minimum_dup()
In list context, returns the smallest key and an array reference
containing all the values for that key from the heap. In scalar
context only the key is returned.
($key, $val) = $h->extract_minimum()
As for $h->minimum(), but the key and value pair is removed from
the heap.
($key, $vals) = $h->extract_minimum_dup()
As for $h->minimum_dup(), but all the values are removed from the
heap.
SEE ALSO
Cache::File
AUTHOR
Chris Leishman <chris@leishman.org>
Based on work by DeWitt Clinton <dewitt@unto.net>
COPYRIGHT
Copyright (C) 2003-2006 Chris Leishman. All Rights Reserved.
This module is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
KIND, either expressed or implied. This program is free software; you
can redistribute or modify it under the same terms as Perl itself.
$Id: Heap.pm,v 1.6 2006/01/31 15:23:58 caleishm Exp $
perl v5.14.1 2006-01-31 Cache::File::Heap(3)