1 /* 2 * Copyright (c) 1989, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Michael Rendell of Memorial University of Newfoundland. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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. 23 * 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 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD: src/usr.bin/tsort/tsort.c,v 1.10.2.1 2001/03/04 09:18:23 kris Exp $ 37 */ 38 39 #ifndef lint 40 static char copyright[] = 41 "@(#) Copyright (c) 1989, 1993, 1994\n\ 42 The Regents of the University of California. All rights reserved.\n"; 43 #endif /* not lint */ 44 45 #ifndef lint 46 static char sccsid[] = "@(#)tsort.c 8.3 (Berkeley) 5/4/95"; 47 #endif /* not lint */ 48 49 #include <sys/types.h> 50 51 #include <ctype.h> 52 #include <db.h> 53 #include <err.h> 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 /* 62 * Topological sort. Input is a list of pairs of strings separated by 63 * white space (spaces, tabs, and/or newlines); strings are written to 64 * standard output in sorted order, one per line. 65 * 66 * usage: 67 * tsort [-dlq] [inputfile] 68 * If no input file is specified, standard input is read. 69 * 70 * Should be compatible with AT&T tsort HOWEVER the output is not identical 71 * (i.e. for most graphs there is more than one sorted order, and this tsort 72 * usually generates a different one then the AT&T tsort). Also, cycle 73 * reporting seems to be more accurate in this version (the AT&T tsort 74 * sometimes says a node is in a cycle when it isn't). 75 * 76 * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90 77 */ 78 #define HASHSIZE 53 /* doesn't need to be big */ 79 #define NF_MARK 0x1 /* marker for cycle detection */ 80 #define NF_ACYCLIC 0x2 /* this node is cycle free */ 81 #define NF_NODEST 0x4 /* Unreachable */ 82 83 84 typedef struct node_str NODE; 85 86 struct node_str { 87 NODE **n_prevp; /* pointer to previous node's n_next */ 88 NODE *n_next; /* next node in graph */ 89 NODE **n_arcs; /* array of arcs to other nodes */ 90 int n_narcs; /* number of arcs in n_arcs[] */ 91 int n_arcsize; /* size of n_arcs[] array */ 92 int n_refcnt; /* # of arcs pointing to this node */ 93 int n_flags; /* NF_* */ 94 char n_name[1]; /* name of this node */ 95 }; 96 97 typedef struct _buf { 98 char *b_buf; 99 int b_bsize; 100 } BUF; 101 102 DB *db; 103 NODE *graph, **cycle_buf, **longest_cycle; 104 int debug, longest, quiet; 105 106 void add_arc __P((char *, char *)); 107 int find_cycle __P((NODE *, NODE *, int, int)); 108 NODE *get_node __P((char *)); 109 void *grow_buf __P((void *, int)); 110 void remove_node __P((NODE *)); 111 void tsort __P((void)); 112 void usage __P((void)); 113 114 int 115 main(argc, argv) 116 int argc; 117 char *argv[]; 118 { 119 register BUF *b; 120 register int c, n; 121 FILE *fp; 122 int bsize, ch, nused; 123 BUF bufs[2]; 124 125 while ((ch = getopt(argc, argv, "dlq")) != -1) 126 switch (ch) { 127 case 'd': 128 debug = 1; 129 break; 130 case 'l': 131 longest = 1; 132 break; 133 case 'q': 134 quiet = 1; 135 break; 136 case '?': 137 default: 138 usage(); 139 } 140 argc -= optind; 141 argv += optind; 142 143 switch (argc) { 144 case 0: 145 fp = stdin; 146 break; 147 case 1: 148 if ((fp = fopen(*argv, "r")) == NULL) 149 err(1, "%s", *argv); 150 break; 151 default: 152 usage(); 153 } 154 155 for (b = bufs, n = 2; --n >= 0; b++) 156 b->b_buf = grow_buf(NULL, b->b_bsize = 1024); 157 158 /* parse input and build the graph */ 159 for (n = 0, c = getc(fp);;) { 160 while (c != EOF && isspace(c)) 161 c = getc(fp); 162 if (c == EOF) 163 break; 164 165 nused = 0; 166 b = &bufs[n]; 167 bsize = b->b_bsize; 168 do { 169 b->b_buf[nused++] = c; 170 if (nused == bsize) 171 b->b_buf = grow_buf(b->b_buf, bsize *= 2); 172 c = getc(fp); 173 } while (c != EOF && !isspace(c)); 174 175 b->b_buf[nused] = '\0'; 176 b->b_bsize = bsize; 177 if (n) 178 add_arc(bufs[0].b_buf, bufs[1].b_buf); 179 n = !n; 180 } 181 (void)fclose(fp); 182 if (n) 183 errx(1, "odd data count"); 184 185 /* do the sort */ 186 tsort(); 187 exit(0); 188 } 189 190 /* double the size of oldbuf and return a pointer to the new buffer. */ 191 void * 192 grow_buf(bp, size) 193 void *bp; 194 int size; 195 { 196 if ((bp = realloc(bp, (u_int)size)) == NULL) 197 err(1, NULL); 198 return (bp); 199 } 200 201 /* 202 * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in 203 * the graph, then add them. 204 */ 205 void 206 add_arc(s1, s2) 207 char *s1, *s2; 208 { 209 register NODE *n1; 210 NODE *n2; 211 int bsize, i; 212 213 n1 = get_node(s1); 214 215 if (!strcmp(s1, s2)) 216 return; 217 218 n2 = get_node(s2); 219 220 /* 221 * Check if this arc is already here. 222 */ 223 for (i = 0; i < n1->n_narcs; i++) 224 if (n1->n_arcs[i] == n2) 225 return; 226 /* 227 * Add it. 228 */ 229 if (n1->n_narcs == n1->n_arcsize) { 230 if (!n1->n_arcsize) 231 n1->n_arcsize = 10; 232 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2; 233 n1->n_arcs = grow_buf(n1->n_arcs, bsize); 234 n1->n_arcsize = bsize / sizeof(*n1->n_arcs); 235 } 236 n1->n_arcs[n1->n_narcs++] = n2; 237 ++n2->n_refcnt; 238 } 239 240 /* Find a node in the graph (insert if not found) and return a pointer to it. */ 241 NODE * 242 get_node(name) 243 char *name; 244 { 245 DBT data, key; 246 NODE *n; 247 248 if (db == NULL && 249 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL) 250 err(1, "db: %s", name); 251 252 key.data = name; 253 key.size = strlen(name) + 1; 254 255 switch ((*db->get)(db, &key, &data, 0)) { 256 case 0: 257 bcopy(data.data, &n, sizeof(n)); 258 return (n); 259 case 1: 260 break; 261 default: 262 case -1: 263 err(1, "db: %s", name); 264 } 265 266 if ((n = malloc(sizeof(NODE) + key.size)) == NULL) 267 err(1, NULL); 268 269 n->n_narcs = 0; 270 n->n_arcsize = 0; 271 n->n_arcs = NULL; 272 n->n_refcnt = 0; 273 n->n_flags = 0; 274 bcopy(name, n->n_name, key.size); 275 276 /* Add to linked list. */ 277 if ((n->n_next = graph) != NULL) 278 graph->n_prevp = &n->n_next; 279 n->n_prevp = &graph; 280 graph = n; 281 282 /* Add to hash table. */ 283 data.data = &n; 284 data.size = sizeof(n); 285 if ((*db->put)(db, &key, &data, 0)) 286 err(1, "db: %s", name); 287 return (n); 288 } 289 290 291 /* 292 * Clear the NODEST flag from all nodes. 293 */ 294 void 295 clear_cycle() 296 { 297 NODE *n; 298 299 for (n = graph; n != NULL; n = n->n_next) 300 n->n_flags &= ~NF_NODEST; 301 } 302 303 /* do topological sort on graph */ 304 void 305 tsort() 306 { 307 register NODE *n, *next; 308 register int cnt, i; 309 310 while (graph != NULL) { 311 /* 312 * Keep getting rid of simple cases until there are none left, 313 * if there are any nodes still in the graph, then there is 314 * a cycle in it. 315 */ 316 do { 317 for (cnt = 0, n = graph; n != NULL; n = next) { 318 next = n->n_next; 319 if (n->n_refcnt == 0) { 320 remove_node(n); 321 ++cnt; 322 } 323 } 324 } while (graph != NULL && cnt); 325 326 if (graph == NULL) 327 break; 328 329 if (!cycle_buf) { 330 /* 331 * Allocate space for two cycle logs - one to be used 332 * as scratch space, the other to save the longest 333 * cycle. 334 */ 335 for (cnt = 0, n = graph; n != NULL; n = n->n_next) 336 ++cnt; 337 cycle_buf = malloc((u_int)sizeof(NODE *) * cnt); 338 longest_cycle = malloc((u_int)sizeof(NODE *) * cnt); 339 if (cycle_buf == NULL || longest_cycle == NULL) 340 err(1, NULL); 341 } 342 for (n = graph; n != NULL; n = n->n_next) 343 if (!(n->n_flags & NF_ACYCLIC)) { 344 if ((cnt = find_cycle(n, n, 0, 0))) { 345 if (!quiet) { 346 warnx("cycle in data"); 347 for (i = 0; i < cnt; i++) 348 warnx("%s", 349 longest_cycle[i]->n_name); 350 } 351 remove_node(n); 352 clear_cycle(); 353 break; 354 } else { 355 /* to avoid further checks */ 356 n->n_flags |= NF_ACYCLIC; 357 clear_cycle(); 358 } 359 } 360 361 if (n == NULL) 362 errx(1, "internal error -- could not find cycle"); 363 } 364 } 365 366 /* print node and remove from graph (does not actually free node) */ 367 void 368 remove_node(n) 369 register NODE *n; 370 { 371 register NODE **np; 372 register int i; 373 374 (void)printf("%s\n", n->n_name); 375 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++) 376 --(*np)->n_refcnt; 377 n->n_narcs = 0; 378 *n->n_prevp = n->n_next; 379 if (n->n_next) 380 n->n_next->n_prevp = n->n_prevp; 381 } 382 383 384 /* look for the longest? cycle from node from to node to. */ 385 int 386 find_cycle(from, to, longest_len, depth) 387 NODE *from, *to; 388 int depth, longest_len; 389 { 390 register NODE **np; 391 register int i, len; 392 393 /* 394 * avoid infinite loops and ignore portions of the graph known 395 * to be acyclic 396 */ 397 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC)) 398 return (0); 399 from->n_flags |= NF_MARK; 400 401 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) { 402 cycle_buf[depth] = *np; 403 if (*np == to) { 404 if (depth + 1 > longest_len) { 405 longest_len = depth + 1; 406 (void)memcpy((char *)longest_cycle, 407 (char *)cycle_buf, 408 longest_len * sizeof(NODE *)); 409 } 410 } else { 411 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST)) 412 continue; 413 len = find_cycle(*np, to, longest_len, depth + 1); 414 415 if (debug) 416 (void)printf("%*s %s->%s %d\n", depth, "", 417 from->n_name, to->n_name, len); 418 419 if (len == 0) 420 (*np)->n_flags |= NF_NODEST; 421 422 if (len > longest_len) 423 longest_len = len; 424 425 if (len > 0 && !longest) 426 break; 427 } 428 } 429 from->n_flags &= ~NF_MARK; 430 return (longest_len); 431 } 432 433 void 434 usage() 435 { 436 (void)fprintf(stderr, "usage: tsort [-dlq] [file]\n"); 437 exit(1); 438 } 439