Heap::Simple
============

DESCRIPTION

A heap is a partially sorted structure where it's always easy to extract the
smallest element. If the collection of elements is changing dynamically, a
heap has less overhead than keeping the collection fully sorted.

The order in which equal elements get extracted is unspecified.

The main order relations supported by this module are "<" (numeric compare)
and "lt" (string compare).

The module allows you to manage data where the elements are of several
allowed types, in particular array references, hash references, objects
or just the keys themselves.

The internals of the module do nothing with the elements inserted except
inspecting the key. This means that if you for example store a blessed
object, that's what you will get back on extract. It's also ok to keep
references to the elements around and make changes to them while they are
in the heap as long as you don't change the key.

SYNOPSIS

    use Heap::Simple;

    # Create a heap
    my $heap = Heap::Simple->new;
    my $heap = Heap::Simple->new(%options);

    # Put data in the heap
    $heap->insert($element);
    # Put data in a "Object" or "Any" heap with a given key
    $heap->key_insert($key, $element);

    # Extract the top value
    $element = $heap->extract_top;	# croaks on an empty heap
    $element = $heap->extract_first;	# returns undef on an empty heap

    # Get the top value but leave it in the heap
    $element = $heap->top;		# croaks on an empty heap
    $element = $heap->first;		# returns undef on an empty heap

    # Find the top key in the heap
    $top_key = $heap->top_key;	  	# return infinity on an empty heap
					# croaks if there's no infinity
    $top_key = $heap->first_key;  	# returns undef   on an empty heap

    # Extract all data whose key is not above a given value
    @elements = $heap->extract_upto($max_key);

    # Find the number of elements
    $count = $heap->count;

    # Empty the heap
    $heap->clear;

    # Get all keys (not sorted)
    @keys = $heap->keys;
    # Get all values (not sorted)
    @values = $heap->values;

    # Find the key corresponding to a value
    $key = $heap->key($value);

    # Get/Set user_data
    $user_data  = $heap->user_data;
    $old_data   = $heap->user_data($new_data);

    # Get/Set infinity
    $infinity     = $heap->infinity;
    $old_infinity = $heap->infinity($new_data);

    # Get the position of a key in an element
    $key_index    = $heap->key_index;
    $key_name     = $heap->key_name;
    $key_method   = $heap->key_method;
    $key_function = $heap->key_function;

    # Return the value of several things that were set in new:
    $wrapped      = $heap->wrapped;
    $max_count    = $heap->max_count;
    $can_die      = $heap->can_die;
    $dirty        = $heap->dirty;
    $order	  = $heap->order;
    @elements     = $heap->elements;
    $elements     = $heap->elements;

    # Move all elements from $heap2 to $heap1
    $heap1->absorb($heap2);	# As if doing a repeated $heap1->insert
    $heap1->key_absorb($heap2);	# As if doing a repeated $heap1->key_insert

    # Which class does the actual work ?
    $implementation = Heap::Simple->implementation;

INSTALLATION

To install this module type the following:

   perl Makefile.PL
   make
   make test
   make install

To install this module into a specific directory, do:
   perl Makefile.PL PREFIX=/name/of/the/directory
   ...the rest is the same...

Please also read the perlmodinstall man page, if available.

DEPENDENCIES

This module doesn't do anything on itself. It needs a plugin actually
implementing the interfaced described above. You can use:

  Heap::Simple::Perl	A pure perl implementation, quite fast actually
  Heap::Simple::XS	An even faster XS implementation, but it needs your
			setup to be able to compile perl modules or you must
			be able to get a binary package for your system

AUTHOR

Ton Hospel, <Heap-Simple@ton.iguana.be>

COPYRIGHT AND LICENCE

Copyright (C) 2004 Ton Hospel

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
