tsort.h
/*
* Copyright 2010 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* This library 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.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Lukas Kuklinek <lkuklinek@redhat.com>
*/
// topological sort
#include "list.h"
#ifndef OSCAP_TSORT_H_
#define OSCAP_TSORT_H_
OSCAP_HIDDEN_START;
// returns nodest with an edge from given node
typedef struct oscap_list* (*oscap_tsort_edge_func)(void *node, void *userdata);
/*
* Topological sort.
*
* Performs a topological sort on a directed graph.
*
* @a edge_func is supposed to return an oscap_list of nodes edges coming from the current node
* (passed to it as an argument) are pointing to. It takes the node as a first argument
* and a pointer passed as @a userdata as a second argument.
*
* The purpose of @a cmp_func is to compare nodes. If it is NULL raw pointer comparison
* is used, which should be good enough in most cases.
*
* Pointer @a output will be set to a list with result. If you want to just check whether
* there is a topological order defined on the graph (i.e. it is an acyclic graph), pass NULL.
* If the function manages to find a topological order of the nodes (returns true),
* it is returned in this variable. Otherwise, it will contain an encountered loop.
* You are responsible to free this list.
*
* @param input set of nodes to sort
* @param output this pointer will be set to the result of the algorithm
* @param edge_func function to return target nodes of outgoing edges from the current one
* @param cmp_func node compasrison function
* @param userdata arbitrary data pointer to be forwarded to the edge_func
* @returns whether the algorithm managed to topologically sort the graph
* @retval true input was sorted, result is in the *output pointer
* @retval false a loop was detected, *output points to the encountered loop
*/
bool oscap_tsort(struct oscap_list *input, struct oscap_list **output, oscap_tsort_edge_func edge_func, oscap_cmp_func cmp_func, void *userdata);
OSCAP_HIDDEN_END;
#endif // OSCAP_TSORT_H_