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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * $FreeBSD: src/usr.bin/tsort/tsort.c,v 1.10.2.1 2001/03/04 09:18:23 kris Exp $
33 * $DragonFly: src/usr.bin/tsort/tsort.c,v 1.4 2004/12/21 20:00:57 cpressey Exp $
35 * @(#) Copyright (c) 1989, 1993, 1994 The Regents of the University of California. All rights reserved.
36 * @(#)tsort.c 8.3 (Berkeley) 5/4/95
39 #include <sys/types.h>
52 * Topological sort. Input is a list of pairs of strings separated by
53 * white space (spaces, tabs, and/or newlines); strings are written to
54 * standard output in sorted order, one per line.
57 * tsort [-dlq] [inputfile]
58 * If no input file is specified, standard input is read.
60 * Should be compatible with AT&T tsort HOWEVER the output is not identical
61 * (i.e. for most graphs there is more than one sorted order, and this tsort
62 * usually generates a different one then the AT&T tsort). Also, cycle
63 * reporting seems to be more accurate in this version (the AT&T tsort
64 * sometimes says a node is in a cycle when it isn't).
66 * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90
68 #define HASHSIZE 53 /* doesn't need to be big */
69 #define NF_MARK 0x1 /* marker for cycle detection */
70 #define NF_ACYCLIC 0x2 /* this node is cycle free */
71 #define NF_NODEST 0x4 /* Unreachable */
74 typedef struct node_str NODE;
77 NODE **n_prevp; /* pointer to previous node's n_next */
78 NODE *n_next; /* next node in graph */
79 NODE **n_arcs; /* array of arcs to other nodes */
80 int n_narcs; /* number of arcs in n_arcs[] */
81 int n_arcsize; /* size of n_arcs[] array */
82 int n_refcnt; /* # of arcs pointing to this node */
83 int n_flags; /* NF_* */
84 char n_name[1]; /* name of this node */
93 NODE *graph, **cycle_buf, **longest_cycle;
94 int debug, longest, quiet;
96 static void add_arc(char *, char *);
97 static void clear_cycle(void);
98 static int find_cycle(NODE *, NODE *, int, int);
99 static NODE *get_node(char *);
100 static void *grow_buf(void *, size_t);
101 static void remove_node(NODE *);
102 static void tsort(void);
103 static void usage(void);
106 main(int argc, char **argv)
111 int bsize, ch, nused;
114 while ((ch = getopt(argc, argv, "dlq")) != -1) {
138 if ((fp = fopen(*argv, "r")) == NULL)
146 for (b = bufs, n = 2; --n >= 0; b++)
147 b->b_buf = grow_buf(NULL, b->b_bsize = 1024);
149 /* Parse input and build the graph. */
150 for (n = 0, c = getc(fp);;) {
151 while (c != EOF && isspace(c))
160 b->b_buf[nused++] = c;
162 b->b_buf = grow_buf(b->b_buf, bsize *= 2);
164 } while (c != EOF && !isspace(c));
166 b->b_buf[nused] = '\0';
169 add_arc(bufs[0].b_buf, bufs[1].b_buf);
174 errx(1, "odd data count");
181 /* Double the size of oldbuf and return a pointer to the new buffer. */
183 grow_buf(void *bp, size_t size)
185 if ((bp = realloc(bp, size)) == NULL)
191 * Add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in
192 * the graph, then add them.
195 add_arc(char *s1, char *s2)
204 if (strcmp(s1, s2) == 0)
210 * Check if this arc is already here.
212 for (i = 0; i < n1->n_narcs; i++)
213 if (n1->n_arcs[i] == n2)
218 if (n1->n_narcs == n1->n_arcsize) {
221 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2;
222 n1->n_arcs = grow_buf(n1->n_arcs, bsize);
223 n1->n_arcsize = bsize / sizeof(*n1->n_arcs);
225 n1->n_arcs[n1->n_narcs++] = n2;
229 /* Find a node in the graph (insert if not found) and return a pointer to it. */
237 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL)
238 err(1, "db: %s", name);
241 key.size = strlen(name) + 1;
243 switch ((*db->get)(db, &key, &data, 0)) {
245 bcopy(data.data, &n, sizeof(n));
251 err(1, "db: %s", name);
254 if ((n = malloc(sizeof(NODE) + key.size)) == NULL)
262 bcopy(name, n->n_name, key.size);
264 /* Add to linked list. */
265 if ((n->n_next = graph) != NULL)
266 graph->n_prevp = &n->n_next;
270 /* Add to hash table. */
272 data.size = sizeof(n);
273 if ((*db->put)(db, &key, &data, 0))
274 err(1, "db: %s", name);
280 * Clear the NODEST flag from all nodes.
287 for (n = graph; n != NULL; n = n->n_next)
288 n->n_flags &= ~NF_NODEST;
291 /* Perform a topological sort of the graph. */
298 while (graph != NULL) {
300 * Keep getting rid of simple cases until there are none left,
301 * and if there are any nodes still in the graph, then there
305 for (cnt = 0, n = graph; n != NULL; n = next) {
307 if (n->n_refcnt == 0) {
312 } while (graph != NULL && cnt != 0);
319 * Allocate space for two cycle logs - one to be used
320 * as scratch space, the other to save the longest
323 for (cnt = 0, n = graph; n != NULL; n = n->n_next)
325 cycle_buf = malloc(sizeof(NODE *) * cnt);
326 longest_cycle = malloc(sizeof(NODE *) * cnt);
327 if (cycle_buf == NULL || longest_cycle == NULL)
330 for (n = graph; n != NULL; n = n->n_next)
331 if (!(n->n_flags & NF_ACYCLIC)) {
332 if ((cnt = find_cycle(n, n, 0, 0))) {
334 warnx("cycle in data");
335 for (i = 0; i < cnt; i++)
337 longest_cycle[i]->n_name);
343 /* To avoid further checks: */
344 n->n_flags |= NF_ACYCLIC;
350 errx(1, "internal error -- could not find cycle");
355 * Print a node and remove it from the graph (does not actually free
364 printf("%s\n", n->n_name);
365 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++)
368 *n->n_prevp = n->n_next;
369 if (n->n_next != NULL)
370 n->n_next->n_prevp = n->n_prevp;
374 /* Look for the (longest?) cycle from node from to node to. */
376 find_cycle(NODE *from, NODE *to, int longest_len, int depth)
382 * Avoid infinite loops and ignore portions of the graph known
385 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC))
387 from->n_flags |= NF_MARK;
389 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) {
390 cycle_buf[depth] = *np;
392 if (depth + 1 > longest_len) {
393 longest_len = depth + 1;
394 memcpy((char *)longest_cycle,
396 longest_len * sizeof(NODE *));
399 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST))
401 len = find_cycle(*np, to, longest_len, depth + 1);
404 printf("%*s %s->%s %d\n", depth, "",
405 from->n_name, to->n_name, len);
409 (*np)->n_flags |= NF_NODEST;
411 if (len > longest_len)
414 if (len > 0 && !longest)
418 from->n_flags &= ~NF_MARK;
419 return (longest_len);
425 fprintf(stderr, "usage: tsort [-dlq] [file]\n");