1ab28bbe03
- Fixes critical mistake in boot.php regarding set_include_path - Fixes minor mistake in text.php regarding strpos order of arguments Note: This change significantly increases Composer running time because Text_Highlither is a PEAR package. I'm already planning to replace it with scrivo/highlight.php.
177 lines
6.9 KiB
PHP
177 lines
6.9 KiB
PHP
<?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 Sérgio Gonçalves 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: Sérgio 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_Manipulator_TopologicalSorter class.
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*
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* @package Structures_Graph
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*/
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require_once 'PEAR.php';
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require_once 'Structures/Graph.php';
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require_once 'Structures/Graph/Node.php';
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require_once 'Structures/Graph/Manipulator/AcyclicTest.php';
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/**
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* The Structures_Graph_Manipulator_TopologicalSorter is a manipulator
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* which is able to return the set of nodes in a graph, sorted by topological
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* order.
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*
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* A graph may only be sorted topologically iff it's a DAG. You can test it
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* with the Structures_Graph_Manipulator_AcyclicTest.
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*
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* @author Sérgio Carvalho <sergio.carvalho@portugalmail.com>
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* @copyright (c) 2004 by Sérgio Carvalho
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* @see Structures_Graph_Manipulator_AcyclicTest
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* @package Structures_Graph
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*/
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class Structures_Graph_Manipulator_TopologicalSorter
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{
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/**
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* This is a variant of Structures_Graph::inDegree which does
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* not count nodes marked as visited.
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*
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* @param object $node Node to check
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*
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* @return integer Number of non-visited nodes that link to this one
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*/
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protected static function _nonVisitedInDegree(&$node)
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{
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$result = 0;
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$graphNodes =& $node->_graph->getNodes();
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foreach (array_keys($graphNodes) as $key) {
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if ((!$graphNodes[$key]->getMetadata('topological-sort-visited'))
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&& $graphNodes[$key]->connectsTo($node)
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) {
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$result++;
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}
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}
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return $result;
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}
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/**
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* Sort implementation
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*
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* @param object $graph Graph to sort
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*
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* @return void
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*/
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protected static function _sort(&$graph)
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{
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// Mark every node as not visited
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$nodes =& $graph->getNodes();
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$nodeKeys = array_keys($nodes);
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$refGenerator = array();
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foreach ($nodeKeys as $key) {
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$refGenerator[] = false;
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$nodes[$key]->setMetadata(
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'topological-sort-visited',
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$refGenerator[sizeof($refGenerator) - 1]
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);
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}
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// Iteratively peel off leaf nodes
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$topologicalLevel = 0;
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do {
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// Find out which nodes are leafs (excluding visited nodes)
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$leafNodes = array();
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foreach ($nodeKeys as $key) {
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if ((!$nodes[$key]->getMetadata('topological-sort-visited'))
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&& static::_nonVisitedInDegree($nodes[$key]) == 0
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) {
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$leafNodes[] =& $nodes[$key];
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}
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}
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// Mark leafs as visited
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$refGenerator[] = $topologicalLevel;
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for ($i = sizeof($leafNodes) - 1; $i>=0; $i--) {
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$visited =& $leafNodes[$i]->getMetadata('topological-sort-visited');
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$visited = true;
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$leafNodes[$i]->setMetadata('topological-sort-visited', $visited);
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$leafNodes[$i]->setMetadata(
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'topological-sort-level',
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$refGenerator[sizeof($refGenerator) - 1]
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);
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}
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$topologicalLevel++;
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} while (sizeof($leafNodes) > 0);
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// Cleanup visited marks
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foreach ($nodeKeys as $key) {
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$nodes[$key]->unsetMetadata('topological-sort-visited');
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}
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}
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/**
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* Sort returns the graph's nodes, sorted by topological order.
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*
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* The result is an array with as many entries as topological levels.
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* Each entry in this array is an array of nodes within
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* the given topological level.
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*
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* @param object $graph Graph to sort
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*
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* @return array The graph's nodes, sorted by topological order.
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*/
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public static function sort(&$graph)
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{
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// We only sort graphs
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if (!is_a($graph, 'Structures_Graph')) {
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return Pear::raiseError(
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'Structures_Graph_Manipulator_TopologicalSorter::sort received'
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. ' an object that is not a Structures_Graph',
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STRUCTURES_GRAPH_ERROR_GENERIC
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);
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}
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if (!Structures_Graph_Manipulator_AcyclicTest::isAcyclic($graph)) {
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return Pear::raiseError(
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'Structures_Graph_Manipulator_TopologicalSorter::sort'
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. ' received an graph that has cycles',
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STRUCTURES_GRAPH_ERROR_GENERIC
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);
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}
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Structures_Graph_Manipulator_TopologicalSorter::_sort($graph);
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$result = array();
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// Fill out result array
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$nodes =& $graph->getNodes();
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$nodeKeys = array_keys($nodes);
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foreach ($nodeKeys as $key) {
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if (!array_key_exists($nodes[$key]->getMetadata('topological-sort-level'), $result)) {
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$result[$nodes[$key]->getMetadata('topological-sort-level')]
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= array();
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}
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$result[$nodes[$key]->getMetadata('topological-sort-level')][]
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=& $nodes[$key];
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$nodes[$key]->unsetMetadata('topological-sort-level');
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}
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return $result;
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}
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}
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?>
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