1 /* $NetBSD: kwset.c,v 1.1.1.1 2016/01/10 21:36:21 christos Exp $ */
2
3 /* kwset.c - search for any of a set of keywords.
4 Copyright 1989, 1998, 2000 Free Software Foundation, Inc.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
20
21 /* Written August 1989 by Mike Haertel.
22 The author may be reached (Email) at the address mike@ai.mit.edu,
23 or (US mail) as Mike Haertel c/o Free Software Foundation. */
24
25 /* The algorithm implemented by these routines bears a startling resemblence
26 to one discovered by Beate Commentz-Walter, although it is not identical.
27 See "A String Matching Algorithm Fast on the Average," Technical Report,
28 IBM-Germany, Scientific Center Heidelberg, Tiergartenstrasse 15, D-6900
29 Heidelberg, Germany. See also Aho, A.V., and M. Corasick, "Efficient
30 String Matching: An Aid to Bibliographic Search," CACM June 1975,
31 Vol. 18, No. 6, which describes the failure function used below. */
32
33 #ifdef HAVE_CONFIG_H
34 # include <config.h>
35 #endif
36 #include <sys/types.h>
37 #include "system.h"
38 #include "kwset.h"
39 #include "obstack.h"
40
41 #ifdef GREP
42 extern char *xmalloc();
43 # undef malloc
44 # define malloc xmalloc
45 #endif
46
47 #define NCHAR (UCHAR_MAX + 1)
48 #define obstack_chunk_alloc malloc
49 #define obstack_chunk_free free
50
51 /* Balanced tree of edges and labels leaving a given trie node. */
52 struct tree
53 {
54 struct tree *llink; /* Left link; MUST be first field. */
55 struct tree *rlink; /* Right link (to larger labels). */
56 struct trie *trie; /* Trie node pointed to by this edge. */
57 unsigned char label; /* Label on this edge. */
58 char balance; /* Difference in depths of subtrees. */
59 };
60
61 /* Node of a trie representing a set of reversed keywords. */
62 struct trie
63 {
64 unsigned int accepting; /* Word index of accepted word, or zero. */
65 struct tree *links; /* Tree of edges leaving this node. */
66 struct trie *parent; /* Parent of this node. */
67 struct trie *next; /* List of all trie nodes in level order. */
68 struct trie *fail; /* Aho-Corasick failure function. */
69 int depth; /* Depth of this node from the root. */
70 int shift; /* Shift function for search failures. */
71 int maxshift; /* Max shift of self and descendents. */
72 };
73
74 /* Structure returned opaquely to the caller, containing everything. */
75 struct kwset
76 {
77 struct obstack obstack; /* Obstack for node allocation. */
78 int words; /* Number of words in the trie. */
79 struct trie *trie; /* The trie itself. */
80 int mind; /* Minimum depth of an accepting node. */
81 int maxd; /* Maximum depth of any node. */
82 unsigned char delta[NCHAR]; /* Delta table for rapid search. */
83 struct trie *next[NCHAR]; /* Table of children of the root. */
84 char *target; /* Target string if there's only one. */
85 int mind2; /* Used in Boyer-Moore search for one string. */
86 char const *trans; /* Character translation table. */
87 };
88
89 /* Allocate and initialize a keyword set object, returning an opaque
90 pointer to it. Return NULL if memory is not available. */
91 kwset_t
kwsalloc(char const * trans)92 kwsalloc (char const *trans)
93 {
94 struct kwset *kwset;
95
96 kwset = (struct kwset *) malloc(sizeof (struct kwset));
97 if (!kwset)
98 return 0;
99
100 obstack_init(&kwset->obstack);
101 kwset->words = 0;
102 kwset->trie
103 = (struct trie *) obstack_alloc(&kwset->obstack, sizeof (struct trie));
104 if (!kwset->trie)
105 {
106 kwsfree((kwset_t) kwset);
107 return 0;
108 }
109 kwset->trie->accepting = 0;
110 kwset->trie->links = 0;
111 kwset->trie->parent = 0;
112 kwset->trie->next = 0;
113 kwset->trie->fail = 0;
114 kwset->trie->depth = 0;
115 kwset->trie->shift = 0;
116 kwset->mind = INT_MAX;
117 kwset->maxd = -1;
118 kwset->target = 0;
119 kwset->trans = trans;
120
121 return (kwset_t) kwset;
122 }
123
124 /* Add the given string to the contents of the keyword set. Return NULL
125 for success, an error message otherwise. */
126 char *
kwsincr(kwset_t kws,char const * text,size_t len)127 kwsincr (kwset_t kws, char const *text, size_t len)
128 {
129 struct kwset *kwset;
130 register struct trie *trie;
131 register unsigned char label;
132 register struct tree *link;
133 register int depth;
134 struct tree *links[12];
135 enum { L, R } dirs[12];
136 struct tree *t, *r, *l, *rl, *lr;
137
138 kwset = (struct kwset *) kws;
139 trie = kwset->trie;
140 text += len;
141
142 /* Descend the trie (built of reversed keywords) character-by-character,
143 installing new nodes when necessary. */
144 while (len--)
145 {
146 label = kwset->trans ? kwset->trans[(unsigned char) *--text] : *--text;
147
148 /* Descend the tree of outgoing links for this trie node,
149 looking for the current character and keeping track
150 of the path followed. */
151 link = trie->links;
152 links[0] = (struct tree *) &trie->links;
153 dirs[0] = L;
154 depth = 1;
155
156 while (link && label != link->label)
157 {
158 links[depth] = link;
159 if (label < link->label)
160 dirs[depth++] = L, link = link->llink;
161 else
162 dirs[depth++] = R, link = link->rlink;
163 }
164
165 /* The current character doesn't have an outgoing link at
166 this trie node, so build a new trie node and install
167 a link in the current trie node's tree. */
168 if (!link)
169 {
170 link = (struct tree *) obstack_alloc(&kwset->obstack,
171 sizeof (struct tree));
172 if (!link)
173 return _("memory exhausted");
174 link->llink = 0;
175 link->rlink = 0;
176 link->trie = (struct trie *) obstack_alloc(&kwset->obstack,
177 sizeof (struct trie));
178 if (!link->trie)
179 return _("memory exhausted");
180 link->trie->accepting = 0;
181 link->trie->links = 0;
182 link->trie->parent = trie;
183 link->trie->next = 0;
184 link->trie->fail = 0;
185 link->trie->depth = trie->depth + 1;
186 link->trie->shift = 0;
187 link->label = label;
188 link->balance = 0;
189
190 /* Install the new tree node in its parent. */
191 if (dirs[--depth] == L)
192 links[depth]->llink = link;
193 else
194 links[depth]->rlink = link;
195
196 /* Back up the tree fixing the balance flags. */
197 while (depth && !links[depth]->balance)
198 {
199 if (dirs[depth] == L)
200 --links[depth]->balance;
201 else
202 ++links[depth]->balance;
203 --depth;
204 }
205
206 /* Rebalance the tree by pointer rotations if necessary. */
207 if (depth && ((dirs[depth] == L && --links[depth]->balance)
208 || (dirs[depth] == R && ++links[depth]->balance)))
209 {
210 switch (links[depth]->balance)
211 {
212 case (char) -2:
213 switch (dirs[depth + 1])
214 {
215 case L:
216 r = links[depth], t = r->llink, rl = t->rlink;
217 t->rlink = r, r->llink = rl;
218 t->balance = r->balance = 0;
219 break;
220 case R:
221 r = links[depth], l = r->llink, t = l->rlink;
222 rl = t->rlink, lr = t->llink;
223 t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl;
224 l->balance = t->balance != 1 ? 0 : -1;
225 r->balance = t->balance != (char) -1 ? 0 : 1;
226 t->balance = 0;
227 break;
228 default:
229 abort ();
230 }
231 break;
232 case 2:
233 switch (dirs[depth + 1])
234 {
235 case R:
236 l = links[depth], t = l->rlink, lr = t->llink;
237 t->llink = l, l->rlink = lr;
238 t->balance = l->balance = 0;
239 break;
240 case L:
241 l = links[depth], r = l->rlink, t = r->llink;
242 lr = t->llink, rl = t->rlink;
243 t->llink = l, l->rlink = lr, t->rlink = r, r->llink = rl;
244 l->balance = t->balance != 1 ? 0 : -1;
245 r->balance = t->balance != (char) -1 ? 0 : 1;
246 t->balance = 0;
247 break;
248 default:
249 abort ();
250 }
251 break;
252 default:
253 abort ();
254 }
255
256 if (dirs[depth - 1] == L)
257 links[depth - 1]->llink = t;
258 else
259 links[depth - 1]->rlink = t;
260 }
261 }
262
263 trie = link->trie;
264 }
265
266 /* Mark the node we finally reached as accepting, encoding the
267 index number of this word in the keyword set so far. */
268 if (!trie->accepting)
269 trie->accepting = 1 + 2 * kwset->words;
270 ++kwset->words;
271
272 /* Keep track of the longest and shortest string of the keyword set. */
273 if (trie->depth < kwset->mind)
274 kwset->mind = trie->depth;
275 if (trie->depth > kwset->maxd)
276 kwset->maxd = trie->depth;
277
278 return 0;
279 }
280
281 /* Enqueue the trie nodes referenced from the given tree in the
282 given queue. */
283 static void
enqueue(struct tree * tree,struct trie ** last)284 enqueue (struct tree *tree, struct trie **last)
285 {
286 if (!tree)
287 return;
288 enqueue(tree->llink, last);
289 enqueue(tree->rlink, last);
290 (*last) = (*last)->next = tree->trie;
291 }
292
293 /* Compute the Aho-Corasick failure function for the trie nodes referenced
294 from the given tree, given the failure function for their parent as
295 well as a last resort failure node. */
296 static void
treefails(register struct tree const * tree,struct trie const * fail,struct trie * recourse)297 treefails (register struct tree const *tree, struct trie const *fail,
298 struct trie *recourse)
299 {
300 register struct tree *link;
301
302 if (!tree)
303 return;
304
305 treefails(tree->llink, fail, recourse);
306 treefails(tree->rlink, fail, recourse);
307
308 /* Find, in the chain of fails going back to the root, the first
309 node that has a descendent on the current label. */
310 while (fail)
311 {
312 link = fail->links;
313 while (link && tree->label != link->label)
314 if (tree->label < link->label)
315 link = link->llink;
316 else
317 link = link->rlink;
318 if (link)
319 {
320 tree->trie->fail = link->trie;
321 return;
322 }
323 fail = fail->fail;
324 }
325
326 tree->trie->fail = recourse;
327 }
328
329 /* Set delta entries for the links of the given tree such that
330 the preexisting delta value is larger than the current depth. */
331 static void
treedelta(register struct tree const * tree,register unsigned int depth,unsigned char delta[])332 treedelta (register struct tree const *tree,
333 register unsigned int depth,
334 unsigned char delta[])
335 {
336 if (!tree)
337 return;
338 treedelta(tree->llink, depth, delta);
339 treedelta(tree->rlink, depth, delta);
340 if (depth < delta[tree->label])
341 delta[tree->label] = depth;
342 }
343
344 /* Return true if A has every label in B. */
345 static int
hasevery(register struct tree const * a,register struct tree const * b)346 hasevery (register struct tree const *a, register struct tree const *b)
347 {
348 if (!b)
349 return 1;
350 if (!hasevery(a, b->llink))
351 return 0;
352 if (!hasevery(a, b->rlink))
353 return 0;
354 while (a && b->label != a->label)
355 if (b->label < a->label)
356 a = a->llink;
357 else
358 a = a->rlink;
359 return !!a;
360 }
361
362 /* Compute a vector, indexed by character code, of the trie nodes
363 referenced from the given tree. */
364 static void
treenext(struct tree const * tree,struct trie * next[])365 treenext (struct tree const *tree, struct trie *next[])
366 {
367 if (!tree)
368 return;
369 treenext(tree->llink, next);
370 treenext(tree->rlink, next);
371 next[tree->label] = tree->trie;
372 }
373
374 /* Compute the shift for each trie node, as well as the delta
375 table and next cache for the given keyword set. */
376 char *
kwsprep(kwset_t kws)377 kwsprep (kwset_t kws)
378 {
379 register struct kwset *kwset;
380 register int i;
381 register struct trie *curr, *fail;
382 register char const *trans;
383 unsigned char delta[NCHAR];
384 struct trie *last, *next[NCHAR];
385
386 kwset = (struct kwset *) kws;
387
388 /* Initial values for the delta table; will be changed later. The
389 delta entry for a given character is the smallest depth of any
390 node at which an outgoing edge is labeled by that character. */
391 if (kwset->mind < 256)
392 for (i = 0; i < NCHAR; ++i)
393 delta[i] = kwset->mind;
394 else
395 for (i = 0; i < NCHAR; ++i)
396 delta[i] = 255;
397
398 /* Check if we can use the simple boyer-moore algorithm, instead
399 of the hairy commentz-walter algorithm. */
400 if (kwset->words == 1 && kwset->trans == 0)
401 {
402 /* Looking for just one string. Extract it from the trie. */
403 kwset->target = obstack_alloc(&kwset->obstack, kwset->mind);
404 for (i = kwset->mind - 1, curr = kwset->trie; i >= 0; --i)
405 {
406 kwset->target[i] = curr->links->label;
407 curr = curr->links->trie;
408 }
409 /* Build the Boyer Moore delta. Boy that's easy compared to CW. */
410 for (i = 0; i < kwset->mind; ++i)
411 delta[(unsigned char) kwset->target[i]] = kwset->mind - (i + 1);
412 kwset->mind2 = kwset->mind;
413 /* Find the minimal delta2 shift that we might make after
414 a backwards match has failed. */
415 for (i = 0; i < kwset->mind - 1; ++i)
416 if (kwset->target[i] == kwset->target[kwset->mind - 1])
417 kwset->mind2 = kwset->mind - (i + 1);
418 }
419 else
420 {
421 /* Traverse the nodes of the trie in level order, simultaneously
422 computing the delta table, failure function, and shift function. */
423 for (curr = last = kwset->trie; curr; curr = curr->next)
424 {
425 /* Enqueue the immediate descendents in the level order queue. */
426 enqueue(curr->links, &last);
427
428 curr->shift = kwset->mind;
429 curr->maxshift = kwset->mind;
430
431 /* Update the delta table for the descendents of this node. */
432 treedelta(curr->links, curr->depth, delta);
433
434 /* Compute the failure function for the decendents of this node. */
435 treefails(curr->links, curr->fail, kwset->trie);
436
437 /* Update the shifts at each node in the current node's chain
438 of fails back to the root. */
439 for (fail = curr->fail; fail; fail = fail->fail)
440 {
441 /* If the current node has some outgoing edge that the fail
442 doesn't, then the shift at the fail should be no larger
443 than the difference of their depths. */
444 if (!hasevery(fail->links, curr->links))
445 if (curr->depth - fail->depth < fail->shift)
446 fail->shift = curr->depth - fail->depth;
447
448 /* If the current node is accepting then the shift at the
449 fail and its descendents should be no larger than the
450 difference of their depths. */
451 if (curr->accepting && fail->maxshift > curr->depth - fail->depth)
452 fail->maxshift = curr->depth - fail->depth;
453 }
454 }
455
456 /* Traverse the trie in level order again, fixing up all nodes whose
457 shift exceeds their inherited maxshift. */
458 for (curr = kwset->trie->next; curr; curr = curr->next)
459 {
460 if (curr->maxshift > curr->parent->maxshift)
461 curr->maxshift = curr->parent->maxshift;
462 if (curr->shift > curr->maxshift)
463 curr->shift = curr->maxshift;
464 }
465
466 /* Create a vector, indexed by character code, of the outgoing links
467 from the root node. */
468 for (i = 0; i < NCHAR; ++i)
469 next[i] = 0;
470 treenext(kwset->trie->links, next);
471
472 if ((trans = kwset->trans) != 0)
473 for (i = 0; i < NCHAR; ++i)
474 kwset->next[i] = next[(unsigned char) trans[i]];
475 else
476 for (i = 0; i < NCHAR; ++i)
477 kwset->next[i] = next[i];
478 }
479
480 /* Fix things up for any translation table. */
481 if ((trans = kwset->trans) != 0)
482 for (i = 0; i < NCHAR; ++i)
483 kwset->delta[i] = delta[(unsigned char) trans[i]];
484 else
485 for (i = 0; i < NCHAR; ++i)
486 kwset->delta[i] = delta[i];
487
488 return 0;
489 }
490
491 #define U(C) ((unsigned char) (C))
492
493 /* Fast boyer-moore search. */
494 static size_t
bmexec(kwset_t kws,char const * text,size_t size)495 bmexec (kwset_t kws, char const *text, size_t size)
496 {
497 struct kwset const *kwset;
498 register unsigned char const *d1;
499 register char const *ep, *sp, *tp;
500 register int d, gc, i, len, md2;
501
502 kwset = (struct kwset const *) kws;
503 len = kwset->mind;
504
505 if (len == 0)
506 return 0;
507 if (len > size)
508 return -1;
509 if (len == 1)
510 {
511 tp = memchr (text, kwset->target[0], size);
512 return tp ? tp - text : -1;
513 }
514
515 d1 = kwset->delta;
516 sp = kwset->target + len;
517 gc = U(sp[-2]);
518 md2 = kwset->mind2;
519 tp = text + len;
520
521 /* Significance of 12: 1 (initial offset) + 10 (skip loop) + 1 (md2). */
522 if (size > 12 * len)
523 /* 11 is not a bug, the initial offset happens only once. */
524 for (ep = text + size - 11 * len;;)
525 {
526 while (tp <= ep)
527 {
528 d = d1[U(tp[-1])], tp += d;
529 d = d1[U(tp[-1])], tp += d;
530 if (d == 0)
531 goto found;
532 d = d1[U(tp[-1])], tp += d;
533 d = d1[U(tp[-1])], tp += d;
534 d = d1[U(tp[-1])], tp += d;
535 if (d == 0)
536 goto found;
537 d = d1[U(tp[-1])], tp += d;
538 d = d1[U(tp[-1])], tp += d;
539 d = d1[U(tp[-1])], tp += d;
540 if (d == 0)
541 goto found;
542 d = d1[U(tp[-1])], tp += d;
543 d = d1[U(tp[-1])], tp += d;
544 }
545 break;
546 found:
547 if (U(tp[-2]) == gc)
548 {
549 for (i = 3; i <= len && U(tp[-i]) == U(sp[-i]); ++i)
550 ;
551 if (i > len)
552 return tp - len - text;
553 }
554 tp += md2;
555 }
556
557 /* Now we have only a few characters left to search. We
558 carefully avoid ever producing an out-of-bounds pointer. */
559 ep = text + size;
560 d = d1[U(tp[-1])];
561 while (d <= ep - tp)
562 {
563 d = d1[U((tp += d)[-1])];
564 if (d != 0)
565 continue;
566 if (U(tp[-2]) == gc)
567 {
568 for (i = 3; i <= len && U(tp[-i]) == U(sp[-i]); ++i)
569 ;
570 if (i > len)
571 return tp - len - text;
572 }
573 d = md2;
574 }
575
576 return -1;
577 }
578
579 /* Hairy multiple string search. */
580 static size_t
cwexec(kwset_t kws,char const * text,size_t len,struct kwsmatch * kwsmatch)581 cwexec (kwset_t kws, char const *text, size_t len, struct kwsmatch *kwsmatch)
582 {
583 struct kwset const *kwset;
584 struct trie * const *next;
585 struct trie const *trie;
586 struct trie const *accept;
587 char const *beg, *lim, *mch, *lmch;
588 register unsigned char c;
589 register unsigned char const *delta;
590 register int d;
591 register char const *end, *qlim;
592 register struct tree const *tree;
593 register char const *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 -1;
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 -1;
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->offset[0] = mch - text;
732 kwsmatch->size[0] = accept->depth;
733 }
734 return mch - text;
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. */
744 size_t
kwsexec(kwset_t kws,char const * text,size_t size,struct kwsmatch * kwsmatch)745 kwsexec (kwset_t kws, char const *text, size_t size,
746 struct kwsmatch *kwsmatch)
747 {
748 struct kwset const *kwset = (struct kwset *) kws;
749 if (kwset->words == 1 && kwset->trans == 0)
750 {
751 size_t ret = bmexec (kws, text, size);
752 if (kwsmatch != 0 && ret != (size_t) -1)
753 {
754 kwsmatch->index = 0;
755 kwsmatch->offset[0] = ret;
756 kwsmatch->size[0] = kwset->mind;
757 }
758 return ret;
759 }
760 else
761 return cwexec(kws, text, size, kwsmatch);
762 }
763
764 /* Free the components of the given keyword set. */
765 void
kwsfree(kwset_t kws)766 kwsfree (kwset_t kws)
767 {
768 struct kwset *kwset;
769
770 kwset = (struct kwset *) kws;
771 obstack_free(&kwset->obstack, 0);
772 free(kws);
773 }
774