kwset.c revision 56918
168349Sobrien/* kwset.c - search for any of a set of keywords. 268349Sobrien Copyright (C) 1989, 1998 Free Software Foundation, Inc. 3354939Sdelphij 468349Sobrien This program is free software; you can redistribute it and/or modify 568349Sobrien it under the terms of the GNU General Public License as published by 668349Sobrien the Free Software Foundation; either version 2, or (at your option) 768349Sobrien any later version. 8354939Sdelphij 9354939Sdelphij This program is distributed in the hope that it will be useful, 10267843Sdelphij but WITHOUT ANY WARRANTY; without even the implied warranty of 1168349Sobrien MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12267843Sdelphij GNU General Public License for more details. 13328874Seadler 14328874Seadler You should have received a copy of the GNU General Public License 15328874Seadler along with this program; if not, write to the Free Software 16328874Seadler Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 17186690Sobrien 02111-1307, USA. */ 18328874Seadler 19328874Seadler/* Written August 1989 by Mike Haertel. 20186690Sobrien The author may be reached (Email) at the address mike@ai.mit.edu, 21328874Seadler or (US mail) as Mike Haertel c/o Free Software Foundation. */ 22328874Seadler 23267843Sdelphij/* The algorithm implemented by these routines bears a startling resemblence 24328874Seadler to one discovered by Beate Commentz-Walter, although it is not identical. 25328874Seadler See "A String Matching Algorithm Fast on the Average," Technical Report, 26328874Seadler IBM-Germany, Scientific Center Heidelberg, Tiergartenstrasse 15, D-6900 27328874Seadler Heidelberg, Germany. See also Aho, A.V., and M. Corasick, "Efficient 28328874Seadler String Matching: An Aid to Bibliographic Search," CACM June 1975, 29328874Seadler Vol. 18, No. 6, which describes the failure function used below. */ 30328874Seadler 31328874Seadler#ifdef HAVE_CONFIG_H 32328874Seadler# include <config.h> 33328874Seadler#endif 34328874Seadler#include <sys/types.h> 35328874Seadler#include "system.h" 36267843Sdelphij#include "kwset.h" 37328874Seadler#include "obstack.h" 38328874Seadler 39328874Seadler#ifdef GREP 40328874Seadlerextern char *xmalloc(); 41267843Sdelphij# undef malloc 42328874Seadler# define malloc xmalloc 43328874Seadler#endif 44328874Seadler 45328874Seadler#define NCHAR (UCHAR_MAX + 1) 46267843Sdelphij#define obstack_chunk_alloc malloc 47328874Seadler#define obstack_chunk_free free 48328874Seadler 49328874Seadler/* Balanced tree of edges and labels leaving a given trie node. */ 50328874Seadlerstruct tree 51328874Seadler{ 52328874Seadler struct tree *llink; /* Left link; MUST be first field. */ 53159764Sobrien struct tree *rlink; /* Right link (to larger labels). */ 54267843Sdelphij struct trie *trie; /* Trie node pointed to by this edge. */ 55186690Sobrien unsigned char label; /* Label on this edge. */ 56159764Sobrien char balance; /* Difference in depths of subtrees. */ 57110949Sobrien}; 58226048Sobrien 59328874Seadler/* Node of a trie representing a set of reversed keywords. */ 60328874Seadlerstruct trie 61110949Sobrien{ 62328874Seadler unsigned int accepting; /* Word index of accepted word, or zero. */ 63 struct tree *links; /* Tree of edges leaving this node. */ 64 struct trie *parent; /* Parent of this node. */ 65 struct trie *next; /* List of all trie nodes in level order. */ 66 struct trie *fail; /* Aho-Corasick failure function. */ 67 int depth; /* Depth of this node from the root. */ 68 int shift; /* Shift function for search failures. */ 69 int maxshift; /* Max shift of self and descendents. */ 70}; 71 72/* Structure returned opaquely to the caller, containing everything. */ 73struct kwset 74{ 75 struct obstack obstack; /* Obstack for node allocation. */ 76 int words; /* Number of words in the trie. */ 77 struct trie *trie; /* The trie itself. */ 78 int mind; /* Minimum depth of an accepting node. */ 79 int maxd; /* Maximum depth of any node. */ 80 unsigned char delta[NCHAR]; /* Delta table for rapid search. */ 81 struct trie *next[NCHAR]; /* Table of children of the root. */ 82 char *target; /* Target string if there's only one. */ 83 int mind2; /* Used in Boyer-Moore search for one string. */ 84 char *trans; /* Character translation table. */ 85}; 86 87/* prototypes */ 88static void enqueue PARAMS((struct tree *, struct trie **)); 89static void treefails PARAMS((register struct tree *, struct trie *, struct trie *)); 90static void treedelta PARAMS((register struct tree *,register unsigned int, unsigned char *)); 91static int hasevery PARAMS((register struct tree *, register struct tree *)); 92static void treenext PARAMS((struct tree *, struct trie **)); 93static char * bmexec PARAMS((kwset_t, char *, size_t)); 94static char * cwexec PARAMS((kwset_t, char *, size_t, struct kwsmatch *)); 95 96/* Allocate and initialize a keyword set object, returning an opaque 97 pointer to it. Return NULL if memory is not available. */ 98kwset_t 99kwsalloc (char *trans) 100{ 101 struct kwset *kwset; 102 103 kwset = (struct kwset *) malloc(sizeof (struct kwset)); 104 if (!kwset) 105 return 0; 106 107 obstack_init(&kwset->obstack); 108 kwset->words = 0; 109 kwset->trie 110 = (struct trie *) obstack_alloc(&kwset->obstack, sizeof (struct trie)); 111 if (!kwset->trie) 112 { 113 kwsfree((kwset_t) kwset); 114 return 0; 115 } 116 kwset->trie->accepting = 0; 117 kwset->trie->links = 0; 118 kwset->trie->parent = 0; 119 kwset->trie->next = 0; 120 kwset->trie->fail = 0; 121 kwset->trie->depth = 0; 122 kwset->trie->shift = 0; 123 kwset->mind = INT_MAX; 124 kwset->maxd = -1; 125 kwset->target = 0; 126 kwset->trans = trans; 127 128 return (kwset_t) kwset; 129} 130 131/* Add the given string to the contents of the keyword set. Return NULL 132 for success, an error message otherwise. */ 133char * 134kwsincr (kwset_t kws, char *text, size_t len) 135{ 136 struct kwset *kwset; 137 register struct trie *trie; 138 register unsigned char label; 139 register struct tree *link; 140 register int depth; 141 struct tree *links[12]; 142 enum { L, R } dirs[12]; 143 struct tree *t, *r, *l, *rl, *lr; 144 145 kwset = (struct kwset *) kws; 146 trie = kwset->trie; 147 text += len; 148 149 /* Descend the trie (built of reversed keywords) character-by-character, 150 installing new nodes when necessary. */ 151 while (len--) 152 { 153 label = kwset->trans ? kwset->trans[(unsigned char) *--text] : *--text; 154 155 /* Descend the tree of outgoing links for this trie node, 156 looking for the current character and keeping track 157 of the path followed. */ 158 link = trie->links; 159 links[0] = (struct tree *) &trie->links; 160 dirs[0] = L; 161 depth = 1; 162 163 while (link && label != link->label) 164 { 165 links[depth] = link; 166 if (label < link->label) 167 dirs[depth++] = L, link = link->llink; 168 else 169 dirs[depth++] = R, link = link->rlink; 170 } 171 172 /* The current character doesn't have an outgoing link at 173 this trie node, so build a new trie node and install 174 a link in the current trie node's tree. */ 175 if (!link) 176 { 177 link = (struct tree *) obstack_alloc(&kwset->obstack, 178 sizeof (struct tree)); 179 if (!link) 180 return _("memory exhausted"); 181 link->llink = 0; 182 link->rlink = 0; 183 link->trie = (struct trie *) obstack_alloc(&kwset->obstack, 184 sizeof (struct trie)); 185 if (!link->trie) 186 return _("memory exhausted"); 187 link->trie->accepting = 0; 188 link->trie->links = 0; 189 link->trie->parent = trie; 190 link->trie->next = 0; 191 link->trie->fail = 0; 192 link->trie->depth = trie->depth + 1; 193 link->trie->shift = 0; 194 link->label = label; 195 link->balance = 0; 196 197 /* Install the new tree node in its parent. */ 198 if (dirs[--depth] == L) 199 links[depth]->llink = link; 200 else 201 links[depth]->rlink = link; 202 203 /* Back up the tree fixing the balance flags. */ 204 while (depth && !links[depth]->balance) 205 { 206 if (dirs[depth] == L) 207 --links[depth]->balance; 208 else 209 ++links[depth]->balance; 210 --depth; 211 } 212 213 /* Rebalance the tree by pointer rotations if necessary. */ 214 if (depth && ((dirs[depth] == L && --links[depth]->balance) 215 || (dirs[depth] == R && ++links[depth]->balance))) 216 { 217 switch (links[depth]->balance) 218 { 219 case (char) -2: 220 switch (dirs[depth + 1]) 221 { 222 case L: 223 r = links[depth], t = r->llink, rl = t->rlink; 224 t->rlink = r, r->llink = rl; 225 t->balance = r->balance = 0; 226 break; 227 case R: 228 r = links[depth], l = r->llink, t = l->rlink; 229 rl = t->rlink, lr = t->llink; 230 t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl; 231 l->balance = t->balance != 1 ? 0 : -1; 232 r->balance = t->balance != (char) -1 ? 0 : 1; 233 t->balance = 0; 234 break; 235 default: 236 abort (); 237 } 238 break; 239 case 2: 240 switch (dirs[depth + 1]) 241 { 242 case R: 243 l = links[depth], t = l->rlink, lr = t->llink; 244 t->llink = l, l->rlink = lr; 245 t->balance = l->balance = 0; 246 break; 247 case L: 248 l = links[depth], r = l->rlink, t = r->llink; 249 lr = t->llink, rl = t->rlink; 250 t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl; 251 l->balance = t->balance != 1 ? 0 : -1; 252 r->balance = t->balance != (char) -1 ? 0 : 1; 253 t->balance = 0; 254 break; 255 default: 256 abort (); 257 } 258 break; 259 default: 260 abort (); 261 } 262 263 if (dirs[depth - 1] == L) 264 links[depth - 1]->llink = t; 265 else 266 links[depth - 1]->rlink = t; 267 } 268 } 269 270 trie = link->trie; 271 } 272 273 /* Mark the node we finally reached as accepting, encoding the 274 index number of this word in the keyword set so far. */ 275 if (!trie->accepting) 276 trie->accepting = 1 + 2 * kwset->words; 277 ++kwset->words; 278 279 /* Keep track of the longest and shortest string of the keyword set. */ 280 if (trie->depth < kwset->mind) 281 kwset->mind = trie->depth; 282 if (trie->depth > kwset->maxd) 283 kwset->maxd = trie->depth; 284 285 return 0; 286} 287 288/* Enqueue the trie nodes referenced from the given tree in the 289 given queue. */ 290static void 291enqueue (struct tree *tree, struct trie **last) 292{ 293 if (!tree) 294 return; 295 enqueue(tree->llink, last); 296 enqueue(tree->rlink, last); 297 (*last) = (*last)->next = tree->trie; 298} 299 300/* Compute the Aho-Corasick failure function for the trie nodes referenced 301 from the given tree, given the failure function for their parent as 302 well as a last resort failure node. */ 303static void 304treefails (register struct tree *tree, struct trie *fail, struct trie *recourse) 305{ 306 register struct tree *link; 307 308 if (!tree) 309 return; 310 311 treefails(tree->llink, fail, recourse); 312 treefails(tree->rlink, fail, recourse); 313 314 /* Find, in the chain of fails going back to the root, the first 315 node that has a descendent on the current label. */ 316 while (fail) 317 { 318 link = fail->links; 319 while (link && tree->label != link->label) 320 if (tree->label < link->label) 321 link = link->llink; 322 else 323 link = link->rlink; 324 if (link) 325 { 326 tree->trie->fail = link->trie; 327 return; 328 } 329 fail = fail->fail; 330 } 331 332 tree->trie->fail = recourse; 333} 334 335/* Set delta entries for the links of the given tree such that 336 the preexisting delta value is larger than the current depth. */ 337static void 338treedelta (register struct tree *tree, 339 register unsigned int depth, 340 unsigned char delta[]) 341{ 342 if (!tree) 343 return; 344 treedelta(tree->llink, depth, delta); 345 treedelta(tree->rlink, depth, delta); 346 if (depth < delta[tree->label]) 347 delta[tree->label] = depth; 348} 349 350/* Return true if A has every label in B. */ 351static int 352hasevery (register struct tree *a, register struct tree *b) 353{ 354 if (!b) 355 return 1; 356 if (!hasevery(a, b->llink)) 357 return 0; 358 if (!hasevery(a, b->rlink)) 359 return 0; 360 while (a && b->label != a->label) 361 if (b->label < a->label) 362 a = a->llink; 363 else 364 a = a->rlink; 365 return !!a; 366} 367 368/* Compute a vector, indexed by character code, of the trie nodes 369 referenced from the given tree. */ 370static void 371treenext (struct tree *tree, struct trie *next[]) 372{ 373 if (!tree) 374 return; 375 treenext(tree->llink, next); 376 treenext(tree->rlink, next); 377 next[tree->label] = tree->trie; 378} 379 380/* Compute the shift for each trie node, as well as the delta 381 table and next cache for the given keyword set. */ 382char * 383kwsprep (kwset_t kws) 384{ 385 register struct kwset *kwset; 386 register int i; 387 register struct trie *curr, *fail; 388 register char *trans; 389 unsigned char delta[NCHAR]; 390 struct trie *last, *next[NCHAR]; 391 392 kwset = (struct kwset *) kws; 393 394 /* Initial values for the delta table; will be changed later. The 395 delta entry for a given character is the smallest depth of any 396 node at which an outgoing edge is labeled by that character. */ 397 if (kwset->mind < 256) 398 for (i = 0; i < NCHAR; ++i) 399 delta[i] = kwset->mind; 400 else 401 for (i = 0; i < NCHAR; ++i) 402 delta[i] = 255; 403 404 /* Check if we can use the simple boyer-moore algorithm, instead 405 of the hairy commentz-walter algorithm. */ 406 if (kwset->words == 1 && kwset->trans == 0) 407 { 408 /* Looking for just one string. Extract it from the trie. */ 409 kwset->target = obstack_alloc(&kwset->obstack, kwset->mind); 410 for (i = kwset->mind - 1, curr = kwset->trie; i >= 0; --i) 411 { 412 kwset->target[i] = curr->links->label; 413 curr = curr->links->trie; 414 } 415 /* Build the Boyer Moore delta. Boy that's easy compared to CW. */ 416 for (i = 0; i < kwset->mind; ++i) 417 delta[(unsigned char) kwset->target[i]] = kwset->mind - (i + 1); 418 kwset->mind2 = kwset->mind; 419 /* Find the minimal delta2 shift that we might make after 420 a backwards match has failed. */ 421 for (i = 0; i < kwset->mind - 1; ++i) 422 if (kwset->target[i] == kwset->target[kwset->mind - 1]) 423 kwset->mind2 = kwset->mind - (i + 1); 424 } 425 else 426 { 427 /* Traverse the nodes of the trie in level order, simultaneously 428 computing the delta table, failure function, and shift function. */ 429 for (curr = last = kwset->trie; curr; curr = curr->next) 430 { 431 /* Enqueue the immediate descendents in the level order queue. */ 432 enqueue(curr->links, &last); 433 434 curr->shift = kwset->mind; 435 curr->maxshift = kwset->mind; 436 437 /* Update the delta table for the descendents of this node. */ 438 treedelta(curr->links, curr->depth, delta); 439 440 /* Compute the failure function for the decendents of this node. */ 441 treefails(curr->links, curr->fail, kwset->trie); 442 443 /* Update the shifts at each node in the current node's chain 444 of fails back to the root. */ 445 for (fail = curr->fail; fail; fail = fail->fail) 446 { 447 /* If the current node has some outgoing edge that the fail 448 doesn't, then the shift at the fail should be no larger 449 than the difference of their depths. */ 450 if (!hasevery(fail->links, curr->links)) 451 if (curr->depth - fail->depth < fail->shift) 452 fail->shift = curr->depth - fail->depth; 453 454 /* If the current node is accepting then the shift at the 455 fail and its descendents should be no larger than the 456 difference of their depths. */ 457 if (curr->accepting && fail->maxshift > curr->depth - fail->depth) 458 fail->maxshift = curr->depth - fail->depth; 459 } 460 } 461 462 /* Traverse the trie in level order again, fixing up all nodes whose 463 shift exceeds their inherited maxshift. */ 464 for (curr = kwset->trie->next; curr; curr = curr->next) 465 { 466 if (curr->maxshift > curr->parent->maxshift) 467 curr->maxshift = curr->parent->maxshift; 468 if (curr->shift > curr->maxshift) 469 curr->shift = curr->maxshift; 470 } 471 472 /* Create a vector, indexed by character code, of the outgoing links 473 from the root node. */ 474 for (i = 0; i < NCHAR; ++i) 475 next[i] = 0; 476 treenext(kwset->trie->links, next); 477 478 if ((trans = kwset->trans) != 0) 479 for (i = 0; i < NCHAR; ++i) 480 kwset->next[i] = next[(unsigned char) trans[i]]; 481 else 482 for (i = 0; i < NCHAR; ++i) 483 kwset->next[i] = next[i]; 484 } 485 486 /* Fix things up for any translation table. */ 487 if ((trans = kwset->trans) != 0) 488 for (i = 0; i < NCHAR; ++i) 489 kwset->delta[i] = delta[(unsigned char) trans[i]]; 490 else 491 for (i = 0; i < NCHAR; ++i) 492 kwset->delta[i] = delta[i]; 493 494 return 0; 495} 496 497#define U(C) ((unsigned char) (C)) 498 499/* Fast boyer-moore search. */ 500static char * 501bmexec (kwset_t kws, char *text, size_t size) 502{ 503 struct kwset *kwset; 504 register unsigned char *d1; 505 register char *ep, *sp, *tp; 506 register int d, gc, i, len, md2; 507 508 kwset = (struct kwset *) kws; 509 len = kwset->mind; 510 511 if (len == 0) 512 return text; 513 if (len > size) 514 return 0; 515 if (len == 1) 516 return memchr(text, kwset->target[0], size); 517 518 d1 = kwset->delta; 519 sp = kwset->target + len; 520 gc = U(sp[-2]); 521 md2 = kwset->mind2; 522 tp = text + len; 523 524 /* Significance of 12: 1 (initial offset) + 10 (skip loop) + 1 (md2). */ 525 if (size > 12 * len) 526 /* 11 is not a bug, the initial offset happens only once. */ 527 for (ep = text + size - 11 * len;;) 528 { 529 while (tp <= ep) 530 { 531 d = d1[U(tp[-1])], tp += d; 532 d = d1[U(tp[-1])], tp += d; 533 if (d == 0) 534 goto found; 535 d = d1[U(tp[-1])], tp += d; 536 d = d1[U(tp[-1])], tp += d; 537 d = d1[U(tp[-1])], tp += d; 538 if (d == 0) 539 goto found; 540 d = d1[U(tp[-1])], tp += d; 541 d = d1[U(tp[-1])], tp += d; 542 d = d1[U(tp[-1])], tp += d; 543 if (d == 0) 544 goto found; 545 d = d1[U(tp[-1])], tp += d; 546 d = d1[U(tp[-1])], tp += d; 547 } 548 break; 549 found: 550 if (U(tp[-2]) == gc) 551 { 552 for (i = 3; i <= len && U(tp[-i]) == U(sp[-i]); ++i) 553 ; 554 if (i > len) 555 return tp - len; 556 } 557 tp += md2; 558 } 559 560 /* Now we have only a few characters left to search. We 561 carefully avoid ever producing an out-of-bounds pointer. */ 562 ep = text + size; 563 d = d1[U(tp[-1])]; 564 while (d <= ep - tp) 565 { 566 d = d1[U((tp += d)[-1])]; 567 if (d != 0) 568 continue; 569 if (U(tp[-2]) == gc) 570 { 571 for (i = 3; i <= len && U(tp[-i]) == U(sp[-i]); ++i) 572 ; 573 if (i > len) 574 return tp - len; 575 } 576 d = md2; 577 } 578 579 return 0; 580} 581 582/* Hairy multiple string search. */ 583static char * 584cwexec (kwset_t kws, char *text, size_t len, struct kwsmatch *kwsmatch) 585{ 586 struct kwset *kwset; 587 struct trie **next, *trie, *accept; 588 char *beg, *lim, *mch, *lmch; 589 register unsigned char c, *delta; 590 register int d; 591 register char *end, *qlim; 592 register struct tree *tree; 593 register char *trans; 594 595#ifdef lint 596 accept = NULL; 597#endif 598 599 /* Initialize register copies and look for easy ways out. */ 600 kwset = (struct kwset *) kws; 601 if (len < kwset->mind) 602 return 0; 603 next = kwset->next; 604 delta = kwset->delta; 605 trans = kwset->trans; 606 lim = text + len; 607 end = text; 608 if ((d = kwset->mind) != 0) 609 mch = 0; 610 else 611 { 612 mch = text, accept = kwset->trie; 613 goto match; 614 } 615 616 if (len >= 4 * kwset->mind) 617 qlim = lim - 4 * kwset->mind; 618 else 619 qlim = 0; 620 621 while (lim - end >= d) 622 { 623 if (qlim && end <= qlim) 624 { 625 end += d - 1; 626 while ((d = delta[c = *end]) && end < qlim) 627 { 628 end += d; 629 end += delta[(unsigned char) *end]; 630 end += delta[(unsigned char) *end]; 631 } 632 ++end; 633 } 634 else 635 d = delta[c = (end += d)[-1]]; 636 if (d) 637 continue; 638 beg = end - 1; 639 trie = next[c]; 640 if (trie->accepting) 641 { 642 mch = beg; 643 accept = trie; 644 } 645 d = trie->shift; 646 while (beg > text) 647 { 648 c = trans ? trans[(unsigned char) *--beg] : *--beg; 649 tree = trie->links; 650 while (tree && c != tree->label) 651 if (c < tree->label) 652 tree = tree->llink; 653 else 654 tree = tree->rlink; 655 if (tree) 656 { 657 trie = tree->trie; 658 if (trie->accepting) 659 { 660 mch = beg; 661 accept = trie; 662 } 663 } 664 else 665 break; 666 d = trie->shift; 667 } 668 if (mch) 669 goto match; 670 } 671 return 0; 672 673 match: 674 /* Given a known match, find the longest possible match anchored 675 at or before its starting point. This is nearly a verbatim 676 copy of the preceding main search loops. */ 677 if (lim - mch > kwset->maxd) 678 lim = mch + kwset->maxd; 679 lmch = 0; 680 d = 1; 681 while (lim - end >= d) 682 { 683 if ((d = delta[c = (end += d)[-1]]) != 0) 684 continue; 685 beg = end - 1; 686 if (!(trie = next[c])) 687 { 688 d = 1; 689 continue; 690 } 691 if (trie->accepting && beg <= mch) 692 { 693 lmch = beg; 694 accept = trie; 695 } 696 d = trie->shift; 697 while (beg > text) 698 { 699 c = trans ? trans[(unsigned char) *--beg] : *--beg; 700 tree = trie->links; 701 while (tree && c != tree->label) 702 if (c < tree->label) 703 tree = tree->llink; 704 else 705 tree = tree->rlink; 706 if (tree) 707 { 708 trie = tree->trie; 709 if (trie->accepting && beg <= mch) 710 { 711 lmch = beg; 712 accept = trie; 713 } 714 } 715 else 716 break; 717 d = trie->shift; 718 } 719 if (lmch) 720 { 721 mch = lmch; 722 goto match; 723 } 724 if (!d) 725 d = 1; 726 } 727 728 if (kwsmatch) 729 { 730 kwsmatch->index = accept->accepting / 2; 731 kwsmatch->beg[0] = mch; 732 kwsmatch->size[0] = accept->depth; 733 } 734 return mch; 735} 736 737/* Search through the given text for a match of any member of the 738 given keyword set. Return a pointer to the first character of 739 the matching substring, or NULL if no match is found. If FOUNDLEN 740 is non-NULL store in the referenced location the length of the 741 matching substring. Similarly, if FOUNDIDX is non-NULL, store 742 in the referenced location the index number of the particular 743 keyword matched. */ 744char * 745kwsexec (kwset_t kws, char *text, size_t size, struct kwsmatch *kwsmatch) 746{ 747 struct kwset *kwset; 748 char *ret; 749 750 kwset = (struct kwset *) kws; 751 if (kwset->words == 1 && kwset->trans == 0) 752 { 753 ret = bmexec(kws, text, size); 754 if (kwsmatch != 0 && ret != 0) 755 { 756 kwsmatch->index = 0; 757 kwsmatch->beg[0] = ret; 758 kwsmatch->size[0] = kwset->mind; 759 } 760 return ret; 761 } 762 else 763 return cwexec(kws, text, size, kwsmatch); 764} 765 766/* Free the components of the given keyword set. */ 767void 768kwsfree (kwset_t kws) 769{ 770 struct kwset *kwset; 771 772 kwset = (struct kwset *) kws; 773 obstack_free(&kwset->obstack, 0); 774 free(kws); 775} 776