2 * Copyright (c) 1989, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Michael Rendell of Memorial University of Newfoundland.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * $FreeBSD: src/usr.bin/tsort/tsort.c,v 1.10.2.1 2001/03/04 09:18:23 kris Exp $
37 * $DragonFly: src/usr.bin/tsort/tsort.c,v 1.4 2004/12/21 20:00:57 cpressey Exp $
39 * @(#) Copyright (c) 1989, 1993, 1994 The Regents of the University of California. All rights reserved.
40 * @(#)tsort.c 8.3 (Berkeley) 5/4/95
43 #include <sys/types.h>
56 * Topological sort. Input is a list of pairs of strings separated by
57 * white space (spaces, tabs, and/or newlines); strings are written to
58 * standard output in sorted order, one per line.
61 * tsort [-dlq] [inputfile]
62 * If no input file is specified, standard input is read.
64 * Should be compatible with AT&T tsort HOWEVER the output is not identical
65 * (i.e. for most graphs there is more than one sorted order, and this tsort
66 * usually generates a different one then the AT&T tsort). Also, cycle
67 * reporting seems to be more accurate in this version (the AT&T tsort
68 * sometimes says a node is in a cycle when it isn't).
70 * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90
72 #define HASHSIZE 53 /* doesn't need to be big */
73 #define NF_MARK 0x1 /* marker for cycle detection */
74 #define NF_ACYCLIC 0x2 /* this node is cycle free */
75 #define NF_NODEST 0x4 /* Unreachable */
78 typedef struct node_str NODE;
81 NODE **n_prevp; /* pointer to previous node's n_next */
82 NODE *n_next; /* next node in graph */
83 NODE **n_arcs; /* array of arcs to other nodes */
84 int n_narcs; /* number of arcs in n_arcs[] */
85 int n_arcsize; /* size of n_arcs[] array */
86 int n_refcnt; /* # of arcs pointing to this node */
87 int n_flags; /* NF_* */
88 char n_name[1]; /* name of this node */
97 NODE *graph, **cycle_buf, **longest_cycle;
98 int debug, longest, quiet;
100 static void add_arc(char *, char *);
101 static void clear_cycle(void);
102 static int find_cycle(NODE *, NODE *, int, int);
103 static NODE *get_node(char *);
104 static void *grow_buf(void *, size_t);
105 static void remove_node(NODE *);
106 static void tsort(void);
107 static void usage(void);
110 main(int argc, char **argv)
115 int bsize, ch, nused;
118 while ((ch = getopt(argc, argv, "dlq")) != -1) {
142 if ((fp = fopen(*argv, "r")) == NULL)
150 for (b = bufs, n = 2; --n >= 0; b++)
151 b->b_buf = grow_buf(NULL, b->b_bsize = 1024);
153 /* Parse input and build the graph. */
154 for (n = 0, c = getc(fp);;) {
155 while (c != EOF && isspace(c))
164 b->b_buf[nused++] = c;
166 b->b_buf = grow_buf(b->b_buf, bsize *= 2);
168 } while (c != EOF && !isspace(c));
170 b->b_buf[nused] = '\0';
173 add_arc(bufs[0].b_buf, bufs[1].b_buf);
178 errx(1, "odd data count");
185 /* Double the size of oldbuf and return a pointer to the new buffer. */
187 grow_buf(void *bp, size_t size)
189 if ((bp = realloc(bp, size)) == NULL)
195 * Add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in
196 * the graph, then add them.
199 add_arc(char *s1, char *s2)
208 if (strcmp(s1, s2) == 0)
214 * Check if this arc is already here.
216 for (i = 0; i < n1->n_narcs; i++)
217 if (n1->n_arcs[i] == n2)
222 if (n1->n_narcs == n1->n_arcsize) {
225 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2;
226 n1->n_arcs = grow_buf(n1->n_arcs, bsize);
227 n1->n_arcsize = bsize / sizeof(*n1->n_arcs);
229 n1->n_arcs[n1->n_narcs++] = n2;
233 /* Find a node in the graph (insert if not found) and return a pointer to it. */
241 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL)
242 err(1, "db: %s", name);
245 key.size = strlen(name) + 1;
247 switch ((*db->get)(db, &key, &data, 0)) {
249 bcopy(data.data, &n, sizeof(n));
255 err(1, "db: %s", name);
258 if ((n = malloc(sizeof(NODE) + key.size)) == NULL)
266 bcopy(name, n->n_name, key.size);
268 /* Add to linked list. */
269 if ((n->n_next = graph) != NULL)
270 graph->n_prevp = &n->n_next;
274 /* Add to hash table. */
276 data.size = sizeof(n);
277 if ((*db->put)(db, &key, &data, 0))
278 err(1, "db: %s", name);
284 * Clear the NODEST flag from all nodes.
291 for (n = graph; n != NULL; n = n->n_next)
292 n->n_flags &= ~NF_NODEST;
295 /* Perform a topological sort of the graph. */
302 while (graph != NULL) {
304 * Keep getting rid of simple cases until there are none left,
305 * and if there are any nodes still in the graph, then there
309 for (cnt = 0, n = graph; n != NULL; n = next) {
311 if (n->n_refcnt == 0) {
316 } while (graph != NULL && cnt != 0);
323 * Allocate space for two cycle logs - one to be used
324 * as scratch space, the other to save the longest
327 for (cnt = 0, n = graph; n != NULL; n = n->n_next)
329 cycle_buf = malloc(sizeof(NODE *) * cnt);
330 longest_cycle = malloc(sizeof(NODE *) * cnt);
331 if (cycle_buf == NULL || longest_cycle == NULL)
334 for (n = graph; n != NULL; n = n->n_next)
335 if (!(n->n_flags & NF_ACYCLIC)) {
336 if ((cnt = find_cycle(n, n, 0, 0))) {
338 warnx("cycle in data");
339 for (i = 0; i < cnt; i++)
341 longest_cycle[i]->n_name);
347 /* To avoid further checks: */
348 n->n_flags |= NF_ACYCLIC;
354 errx(1, "internal error -- could not find cycle");
359 * Print a node and remove it from the graph (does not actually free
368 printf("%s\n", n->n_name);
369 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++)
372 *n->n_prevp = n->n_next;
373 if (n->n_next != NULL)
374 n->n_next->n_prevp = n->n_prevp;
378 /* Look for the (longest?) cycle from node from to node to. */
380 find_cycle(NODE *from, NODE *to, int longest_len, int depth)
386 * Avoid infinite loops and ignore portions of the graph known
389 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC))
391 from->n_flags |= NF_MARK;
393 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) {
394 cycle_buf[depth] = *np;
396 if (depth + 1 > longest_len) {
397 longest_len = depth + 1;
398 memcpy((char *)longest_cycle,
400 longest_len * sizeof(NODE *));
403 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST))
405 len = find_cycle(*np, to, longest_len, depth + 1);
408 printf("%*s %s->%s %d\n", depth, "",
409 from->n_name, to->n_name, len);
413 (*np)->n_flags |= NF_NODEST;
415 if (len > longest_len)
418 if (len > 0 && !longest)
422 from->n_flags &= ~NF_MARK;
423 return (longest_len);
429 fprintf(stderr, "usage: tsort [-dlq] [file]\n");