AlkantarClanX12
Current Path : /proc/self/root/opt/alt/php82/usr/share/pear/Structures/Graph/Manipulator/ |
Current File : //proc/self/root/opt/alt/php82/usr/share/pear/Structures/Graph/Manipulator/TopologicalSorter.php |
<?php /* vim: set expandtab tabstop=4 shiftwidth=4 foldmethod=marker: */ // +-----------------------------------------------------------------------------+ // | Copyright (c) 2003 S�rgio Gon�alves Carvalho | // +-----------------------------------------------------------------------------+ // | This file is part of Structures_Graph. | // | | // | Structures_Graph is free software; you can redistribute it and/or modify | // | it under the terms of the GNU Lesser General Public License as published by | // | the Free Software Foundation; either version 2.1 of the License, or | // | (at your option) any later version. | // | | // | Structures_Graph is distributed in the hope that it will be useful, | // | but WITHOUT ANY WARRANTY; without even the implied warranty of | // | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | // | GNU Lesser General Public License for more details. | // | | // | You should have received a copy of the GNU Lesser General Public License | // | along with Structures_Graph; if not, write to the Free Software | // | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | // | 02111-1307 USA | // +-----------------------------------------------------------------------------+ // | Author: S�rgio Carvalho <sergio.carvalho@portugalmail.com> | // +-----------------------------------------------------------------------------+ // /** * This file contains the definition of the Structures_Graph_Manipulator_TopologicalSorter class. * * @package Structures_Graph */ require_once 'PEAR.php'; require_once 'Structures/Graph.php'; require_once 'Structures/Graph/Node.php'; require_once 'Structures/Graph/Manipulator/AcyclicTest.php'; /** * The Structures_Graph_Manipulator_TopologicalSorter is a manipulator * which is able to return the set of nodes in a graph, sorted by topological * order. * * A graph may only be sorted topologically iff it's a DAG. You can test it * with the Structures_Graph_Manipulator_AcyclicTest. * * @author S�rgio Carvalho <sergio.carvalho@portugalmail.com> * @copyright (c) 2004 by S�rgio Carvalho * @see Structures_Graph_Manipulator_AcyclicTest * @package Structures_Graph */ class Structures_Graph_Manipulator_TopologicalSorter { /** * This is a variant of Structures_Graph::inDegree which does * not count nodes marked as visited. * * @param object $node Node to check * * @return integer Number of non-visited nodes that link to this one */ protected static function _nonVisitedInDegree(&$node) { $result = 0; $graphNodes =& $node->_graph->getNodes(); foreach (array_keys($graphNodes) as $key) { if ((!$graphNodes[$key]->getMetadata('topological-sort-visited')) && $graphNodes[$key]->connectsTo($node) ) { $result++; } } return $result; } /** * Sort implementation * * @param object $graph Graph to sort * * @return void */ protected static function _sort(&$graph) { // Mark every node as not visited $nodes =& $graph->getNodes(); $nodeKeys = array_keys($nodes); $refGenerator = array(); foreach ($nodeKeys as $key) { $refGenerator[] = false; $nodes[$key]->setMetadata( 'topological-sort-visited', $refGenerator[sizeof($refGenerator) - 1] ); } // Iteratively peel off leaf nodes $topologicalLevel = 0; do { // Find out which nodes are leafs (excluding visited nodes) $leafNodes = array(); foreach ($nodeKeys as $key) { if ((!$nodes[$key]->getMetadata('topological-sort-visited')) && static::_nonVisitedInDegree($nodes[$key]) == 0 ) { $leafNodes[] =& $nodes[$key]; } } // Mark leafs as visited $refGenerator[] = $topologicalLevel; for ($i = sizeof($leafNodes) - 1; $i>=0; $i--) { $visited =& $leafNodes[$i]->getMetadata('topological-sort-visited'); $visited = true; $leafNodes[$i]->setMetadata('topological-sort-visited', $visited); $leafNodes[$i]->setMetadata( 'topological-sort-level', $refGenerator[sizeof($refGenerator) - 1] ); } $topologicalLevel++; } while (sizeof($leafNodes) > 0); // Cleanup visited marks foreach ($nodeKeys as $key) { $nodes[$key]->unsetMetadata('topological-sort-visited'); } } /** * Sort returns the graph's nodes, sorted by topological order. * * The result is an array with as many entries as topological levels. * Each entry in this array is an array of nodes within * the given topological level. * * @param object $graph Graph to sort * * @return array The graph's nodes, sorted by topological order. */ public static function sort(&$graph) { // We only sort graphs if (!is_a($graph, 'Structures_Graph')) { return Pear::raiseError( 'Structures_Graph_Manipulator_TopologicalSorter::sort received' . ' an object that is not a Structures_Graph', STRUCTURES_GRAPH_ERROR_GENERIC ); } if (!Structures_Graph_Manipulator_AcyclicTest::isAcyclic($graph)) { return Pear::raiseError( 'Structures_Graph_Manipulator_TopologicalSorter::sort' . ' received an graph that has cycles', STRUCTURES_GRAPH_ERROR_GENERIC ); } Structures_Graph_Manipulator_TopologicalSorter::_sort($graph); $result = array(); // Fill out result array $nodes =& $graph->getNodes(); $nodeKeys = array_keys($nodes); foreach ($nodeKeys as $key) { if (!array_key_exists($nodes[$key]->getMetadata('topological-sort-level'), $result)) { $result[$nodes[$key]->getMetadata('topological-sort-level')] = array(); } $result[$nodes[$key]->getMetadata('topological-sort-level')][] =& $nodes[$key]; $nodes[$key]->unsetMetadata('topological-sort-level'); } return $result; } } ?>