mirror of
https://github.com/friendica/friendica
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343 lines
11 KiB
PHP
343 lines
11 KiB
PHP
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<?php
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/* vim: set expandtab tabstop=4 shiftwidth=4 foldmethod=marker: */
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// +-----------------------------------------------------------------------------+
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// | Copyright (c) 2003 S<>rgio Gon<6F>alves Carvalho |
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// +-----------------------------------------------------------------------------+
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// | This file is part of Structures_Graph. |
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// | |
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// | Structures_Graph is free software; you can redistribute it and/or modify |
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// | it under the terms of the GNU Lesser General Public License as published by |
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// | the Free Software Foundation; either version 2.1 of the License, or |
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// | (at your option) any later version. |
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// | |
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// | Structures_Graph is distributed in the hope that it will be useful, |
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// | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// | GNU Lesser General Public License for more details. |
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// | |
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// | You should have received a copy of the GNU Lesser General Public License |
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// | along with Structures_Graph; if not, write to the Free Software |
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// | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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// | 02111-1307 USA |
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// +-----------------------------------------------------------------------------+
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// | Author: S<>rgio Carvalho <sergio.carvalho@portugalmail.com> |
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// +-----------------------------------------------------------------------------+
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//
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/**
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* This file contains the definition of the Structures_Graph_Node class
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*
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* @see Structures_Graph_Node
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* @package Structures_Graph
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*/
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/* dependencies {{{ */
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/** */
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require_once 'PEAR.php';
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/** */
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require_once 'Structures/Graph.php';
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/* }}} */
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/* class Structures_Graph_Node {{{ */
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/**
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* The Structures_Graph_Node class represents a Node that can be member of a
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* graph node set.
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*
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* A graph node can contain data. Under this API, the node contains default data,
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* and key index data. It behaves, thus, both as a regular data node, and as a
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* dictionary (or associative array) node.
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*
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* Regular data is accessed via getData and setData. Key indexed data is accessed
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* via getMetadata and setMetadata.
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*
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* @author S<EFBFBD>rgio Carvalho <sergio.carvalho@portugalmail.com>
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* @copyright (c) 2004 by S<EFBFBD>rgio Carvalho
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* @package Structures_Graph
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*/
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/* }}} */
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class Structures_Graph_Node {
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/* fields {{{ */
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/**
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* @access private
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*/
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var $_data = null;
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/** @access private */
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var $_metadata = array();
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/** @access private */
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var $_arcs = array();
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/** @access private */
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var $_graph = null;
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/* }}} */
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/* Constructor {{{ */
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/**
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*
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* Constructor
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*
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* @access public
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*/
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function __construct() {
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}
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/* }}} */
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/* getGraph {{{ */
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/**
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*
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* Node graph getter
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*
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* @return Structures_Graph Graph where node is stored
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* @access public
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*/
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function &getGraph() {
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return $this->_graph;
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}
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/* }}} */
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/* setGraph {{{ */
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/**
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*
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* Node graph setter. This method should not be called directly. Use Graph::addNode instead.
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*
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* @param Structures_Graph Set the graph for this node.
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* @see Structures_Graph::addNode()
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* @access public
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*/
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function setGraph(&$graph) {
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$this->_graph =& $graph;
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}
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/* }}} */
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/* getData {{{ */
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/**
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*
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* Node data getter.
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*
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* Each graph node can contain a reference to one variable. This is the getter for that reference.
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*
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* @return mixed Data stored in node
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* @access public
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*/
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function &getData() {
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return $this->_data;
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}
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/* }}} */
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/* setData {{{ */
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/**
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*
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* Node data setter
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*
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* Each graph node can contain a reference to one variable. This is the setter for that reference.
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*
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* @return mixed Data to store in node
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* @access public
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*/
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function setData(&$data) {
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$this->_data =& $data;
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}
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/* }}} */
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/* metadataKeyExists {{{ */
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/**
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*
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* Test for existence of metadata under a given key.
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*
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* Each graph node can contain multiple 'metadata' entries, each stored under a different key, as in an
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* associative array or in a dictionary. This method tests whether a given metadata key exists for this node.
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*
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* @param string Key to test
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* @return boolean
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* @access public
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*/
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function metadataKeyExists($key) {
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return array_key_exists($key, $this->_metadata);
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}
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/* }}} */
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/* getMetadata {{{ */
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/**
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*
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* Node metadata getter
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*
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* Each graph node can contain multiple 'metadata' entries, each stored under a different key, as in an
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* associative array or in a dictionary. This method gets the data under the given key. If the key does
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* not exist, an error will be thrown, so testing using metadataKeyExists might be needed.
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*
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* @param string Key
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* @param boolean nullIfNonexistent (defaults to false).
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* @return mixed Metadata Data stored in node under given key
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* @see metadataKeyExists
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* @access public
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*/
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function &getMetadata($key, $nullIfNonexistent = false) {
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if (array_key_exists($key, $this->_metadata)) {
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return $this->_metadata[$key];
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} else {
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if ($nullIfNonexistent) {
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$a = null;
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return $a;
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} else {
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$a = Pear::raiseError('Structures_Graph_Node::getMetadata: Requested key does not exist', STRUCTURES_GRAPH_ERROR_GENERIC);
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return $a;
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}
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}
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}
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/* }}} */
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/* unsetMetadata {{{ */
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/**
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*
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* Delete metadata by key
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*
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* Each graph node can contain multiple 'metadata' entries, each stored under a different key, as in an
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* associative array or in a dictionary. This method removes any data that might be stored under the provided key.
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* If the key does not exist, no error is thrown, so it is safe using this method without testing for key existence.
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*
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* @param string Key
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* @access public
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*/
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function unsetMetadata($key) {
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if (array_key_exists($key, $this->_metadata)) unset($this->_metadata[$key]);
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}
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/* }}} */
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/* setMetadata {{{ */
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/**
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*
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* Node metadata setter
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*
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* Each graph node can contain multiple 'metadata' entries, each stored under a different key, as in an
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* associative array or in a dictionary. This method stores data under the given key. If the key already exists,
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* previously stored data is discarded.
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*
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* @param string Key
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* @param mixed Data
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* @access public
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*/
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function setMetadata($key, &$data) {
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$this->_metadata[$key] =& $data;
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}
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/* }}} */
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/* _connectTo {{{ */
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/** @access private */
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function _connectTo(&$destinationNode) {
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$this->_arcs[] =& $destinationNode;
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}
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/* }}} */
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/* connectTo {{{ */
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/**
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*
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* Connect this node to another one.
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*
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* If the graph is not directed, the reverse arc, connecting $destinationNode to $this is also created.
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*
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* @param Structures_Graph_Node Node to connect to
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* @access public
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*/
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function connectTo(&$destinationNode) {
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// We only connect to nodes
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if (!is_a($destinationNode, 'Structures_Graph_Node')) return Pear::raiseError('Structures_Graph_Node::connectTo received an object that is not a Structures_Graph_Node', STRUCTURES_GRAPH_ERROR_GENERIC);
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// Nodes must already be in graphs to be connected
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if ($this->_graph == null) return Pear::raiseError('Structures_Graph_Node::connectTo Tried to connect a node that is not in a graph', STRUCTURES_GRAPH_ERROR_GENERIC);
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if ($destinationNode->getGraph() == null) return Pear::raiseError('Structures_Graph_Node::connectTo Tried to connect to a node that is not in a graph', STRUCTURES_GRAPH_ERROR_GENERIC);
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// Connect here
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$this->_connectTo($destinationNode);
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// If graph is undirected, connect back
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if (!$this->_graph->isDirected()) {
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$destinationNode->_connectTo($this);
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}
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}
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/* }}} */
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/* getNeighbours {{{ */
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/**
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*
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* Return nodes connected to this one.
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*
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* @return array Array of nodes
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* @access public
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*/
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function getNeighbours() {
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return $this->_arcs;
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}
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/* }}} */
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/* connectsTo {{{ */
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/**
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*
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* Test wether this node has an arc to the target node
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*
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* @return boolean True if the two nodes are connected
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* @access public
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*/
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function connectsTo(&$target) {
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if (version_compare(PHP_VERSION, '5.0.0') >= 0) {
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return in_array($target, $this->getNeighbours(), true);
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}
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$copy = $target;
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$arcKeys = array_keys($this->_arcs);
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foreach($arcKeys as $key) {
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/* ZE1 chokes on this expression:
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if ($target === $arc) return true;
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so, we'll use more convoluted stuff
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*/
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$arc =& $this->_arcs[$key];
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$target = true;
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if ($arc === true) {
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$target = false;
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if ($arc === false) {
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$target = $copy;
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return true;
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}
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}
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}
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$target = $copy;
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return false;
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}
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/* }}} */
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/* inDegree {{{ */
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/**
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*
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* Calculate the in degree of the node.
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*
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* The indegree for a node is the number of arcs entering the node. For non directed graphs,
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* the indegree is equal to the outdegree.
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*
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* @return integer In degree of the node
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* @access public
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*/
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function inDegree() {
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if ($this->_graph == null) return 0;
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if (!$this->_graph->isDirected()) return $this->outDegree();
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$result = 0;
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$graphNodes =& $this->_graph->getNodes();
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foreach (array_keys($graphNodes) as $key) {
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if ($graphNodes[$key]->connectsTo($this)) $result++;
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}
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return $result;
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}
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/* }}} */
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/* outDegree {{{ */
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/**
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*
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* Calculate the out degree of the node.
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*
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* The outdegree for a node is the number of arcs exiting the node. For non directed graphs,
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* the outdegree is always equal to the indegree.
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*
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* @return integer Out degree of the node
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* @access public
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*/
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function outDegree() {
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if ($this->_graph == null) return 0;
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return sizeof($this->_arcs);
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}
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/* }}} */
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}
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?>
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