Open SCAP Library
tsort.h
1 /*
2  * Copyright 2010 Red Hat Inc., Durham, North Carolina.
3  * All Rights Reserved.
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Authors:
20  * Lukas Kuklinek <lkuklinek@redhat.com>
21  */
22 
23 
24 // topological sort
25 
26 #include "list.h"
27 
28 #ifndef OSCAP_TSORT_H_
29 #define OSCAP_TSORT_H_
30 
31 
32 // returns nodest with an edge from given node
33 typedef struct oscap_list* (*oscap_tsort_edge_func)(void *node, void *userdata);
34 
35 /*
36  * Topological sort.
37  *
38  * Performs a topological sort on a directed graph.
39  *
40  * @a edge_func is supposed to return an oscap_list of nodes edges coming from the current node
41  * (passed to it as an argument) are pointing to. It takes the node as a first argument
42  * and a pointer passed as @a userdata as a second argument.
43  *
44  * The purpose of @a cmp_func is to compare nodes. If it is NULL raw pointer comparison
45  * is used, which should be good enough in most cases.
46  *
47  * Pointer @a output will be set to a list with result. If you want to just check whether
48  * there is a topological order defined on the graph (i.e. it is an acyclic graph), pass NULL.
49  * If the function manages to find a topological order of the nodes (returns true),
50  * it is returned in this variable. Otherwise, it will contain an encountered loop.
51  * You are responsible to free this list.
52  *
53  * @param input set of nodes to sort
54  * @param output this pointer will be set to the result of the algorithm
55  * @param edge_func function to return target nodes of outgoing edges from the current one
56  * @param cmp_func node compasrison function
57  * @param userdata arbitrary data pointer to be forwarded to the edge_func
58  * @returns whether the algorithm managed to topologically sort the graph
59  * @retval true input was sorted, result is in the *output pointer
60  * @retval false a loop was detected, *output points to the encountered loop
61  */
62 bool oscap_tsort(struct oscap_list *input, struct oscap_list **output, oscap_tsort_edge_func edge_func, oscap_cmp_func cmp_func, void *userdata);
63 
64 
65 #endif // OSCAP_TSORT_H_
66 
oscap_list
Definition: list.h:53