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Commit | Line | Data |
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48bf5def RN |
1 | /* |
2 | * NFA utilities. | |
3 | * This file is #included by regcomp.c. | |
4 | * | |
3ca4086b VS |
5 | * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved. |
6 | * | |
48bf5def RN |
7 | * Development of this software was funded, in part, by Cray Research Inc., |
8 | * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics | |
9 | * Corporation, none of whom are responsible for the results. The author | |
3ca4086b VS |
10 | * thanks all of them. |
11 | * | |
48bf5def RN |
12 | * Redistribution and use in source and binary forms -- with or without |
13 | * modification -- are permitted for any purpose, provided that | |
14 | * redistributions in source form retain this entire copyright notice and | |
15 | * indicate the origin and nature of any modifications. | |
3ca4086b | 16 | * |
48bf5def RN |
17 | * I'd appreciate being given credit for this package in the documentation |
18 | * of software which uses it, but that is not a requirement. | |
3ca4086b | 19 | * |
48bf5def RN |
20 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, |
21 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY | |
22 | * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL | |
23 | * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
24 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
25 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; | |
26 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | |
27 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR | |
28 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF | |
29 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
30 | * | |
48bf5def RN |
31 | * |
32 | * | |
33 | * One or two things that technically ought to be in here | |
34 | * are actually in color.c, thanks to some incestuous relationships in | |
35 | * the color chains. | |
36 | */ | |
37 | ||
3ca4086b VS |
38 | #define NISERR() VISERR(nfa->v) |
39 | #define NERR(e) VERR(nfa->v, (e)) | |
48bf5def RN |
40 | |
41 | ||
42 | /* | |
3ca4086b VS |
43 | - newnfa - set up an NFA |
44 | ^ static struct nfa *newnfa(struct vars *, struct colormap *, struct nfa *); | |
48bf5def | 45 | */ |
3ca4086b VS |
46 | static struct nfa * /* the NFA, or NULL */ |
47 | newnfa(v, cm, parent) | |
48 | struct vars *v; | |
49 | struct colormap *cm; | |
50 | struct nfa *parent; /* NULL if primary NFA */ | |
48bf5def RN |
51 | { |
52 | struct nfa *nfa; | |
53 | ||
3ca4086b | 54 | nfa = (struct nfa *)MALLOC(sizeof(struct nfa)); |
48bf5def RN |
55 | if (nfa == NULL) |
56 | return NULL; | |
57 | ||
58 | nfa->states = NULL; | |
59 | nfa->slast = NULL; | |
60 | nfa->free = NULL; | |
61 | nfa->nstates = 0; | |
62 | nfa->cm = cm; | |
63 | nfa->v = v; | |
64 | nfa->bos[0] = nfa->bos[1] = COLORLESS; | |
65 | nfa->eos[0] = nfa->eos[1] = COLORLESS; | |
66 | nfa->post = newfstate(nfa, '@'); /* number 0 */ | |
67 | nfa->pre = newfstate(nfa, '>'); /* number 1 */ | |
68 | nfa->parent = parent; | |
69 | ||
3ca4086b | 70 | nfa->init = newstate(nfa); /* may become invalid later */ |
48bf5def | 71 | nfa->final = newstate(nfa); |
3ca4086b | 72 | if (ISERR()) { |
48bf5def RN |
73 | freenfa(nfa); |
74 | return NULL; | |
75 | } | |
76 | rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init); | |
77 | newarc(nfa, '^', 1, nfa->pre, nfa->init); | |
78 | newarc(nfa, '^', 0, nfa->pre, nfa->init); | |
79 | rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post); | |
80 | newarc(nfa, '$', 1, nfa->final, nfa->post); | |
81 | newarc(nfa, '$', 0, nfa->final, nfa->post); | |
82 | ||
3ca4086b | 83 | if (ISERR()) { |
48bf5def RN |
84 | freenfa(nfa); |
85 | return NULL; | |
86 | } | |
87 | return nfa; | |
88 | } | |
89 | ||
90 | /* | |
3ca4086b VS |
91 | - freenfa - free an entire NFA |
92 | ^ static VOID freenfa(struct nfa *); | |
48bf5def | 93 | */ |
3ca4086b VS |
94 | static VOID |
95 | freenfa(nfa) | |
96 | struct nfa *nfa; | |
48bf5def RN |
97 | { |
98 | struct state *s; | |
99 | ||
3ca4086b VS |
100 | while ((s = nfa->states) != NULL) { |
101 | s->nins = s->nouts = 0; /* don't worry about arcs */ | |
48bf5def RN |
102 | freestate(nfa, s); |
103 | } | |
3ca4086b | 104 | while ((s = nfa->free) != NULL) { |
48bf5def RN |
105 | nfa->free = s->next; |
106 | destroystate(nfa, s); | |
107 | } | |
108 | ||
109 | nfa->slast = NULL; | |
110 | nfa->nstates = -1; | |
111 | nfa->pre = NULL; | |
112 | nfa->post = NULL; | |
113 | FREE(nfa); | |
114 | } | |
115 | ||
116 | /* | |
3ca4086b VS |
117 | - newstate - allocate an NFA state, with zero flag value |
118 | ^ static struct state *newstate(struct nfa *); | |
48bf5def | 119 | */ |
3ca4086b VS |
120 | static struct state * /* NULL on error */ |
121 | newstate(nfa) | |
122 | struct nfa *nfa; | |
48bf5def RN |
123 | { |
124 | struct state *s; | |
125 | ||
3ca4086b | 126 | if (nfa->free != NULL) { |
48bf5def RN |
127 | s = nfa->free; |
128 | nfa->free = s->next; | |
3ca4086b VS |
129 | } else { |
130 | s = (struct state *)MALLOC(sizeof(struct state)); | |
131 | if (s == NULL) { | |
48bf5def RN |
132 | NERR(REG_ESPACE); |
133 | return NULL; | |
134 | } | |
135 | s->oas.next = NULL; | |
136 | s->free = NULL; | |
137 | s->noas = 0; | |
138 | } | |
139 | ||
140 | assert(nfa->nstates >= 0); | |
141 | s->no = nfa->nstates++; | |
142 | s->flag = 0; | |
143 | if (nfa->states == NULL) | |
144 | nfa->states = s; | |
145 | s->nins = 0; | |
146 | s->ins = NULL; | |
147 | s->nouts = 0; | |
148 | s->outs = NULL; | |
149 | s->tmp = NULL; | |
150 | s->next = NULL; | |
3ca4086b | 151 | if (nfa->slast != NULL) { |
48bf5def RN |
152 | assert(nfa->slast->next == NULL); |
153 | nfa->slast->next = s; | |
154 | } | |
155 | s->prev = nfa->slast; | |
156 | nfa->slast = s; | |
157 | return s; | |
158 | } | |
159 | ||
160 | /* | |
3ca4086b VS |
161 | - newfstate - allocate an NFA state with a specified flag value |
162 | ^ static struct state *newfstate(struct nfa *, int flag); | |
48bf5def | 163 | */ |
3ca4086b VS |
164 | static struct state * /* NULL on error */ |
165 | newfstate(nfa, flag) | |
166 | struct nfa *nfa; | |
167 | int flag; | |
48bf5def RN |
168 | { |
169 | struct state *s; | |
170 | ||
171 | s = newstate(nfa); | |
172 | if (s != NULL) | |
3ca4086b | 173 | s->flag = (char)flag; |
48bf5def RN |
174 | return s; |
175 | } | |
176 | ||
177 | /* | |
3ca4086b VS |
178 | - dropstate - delete a state's inarcs and outarcs and free it |
179 | ^ static VOID dropstate(struct nfa *, struct state *); | |
48bf5def | 180 | */ |
3ca4086b VS |
181 | static VOID |
182 | dropstate(nfa, s) | |
183 | struct nfa *nfa; | |
184 | struct state *s; | |
48bf5def RN |
185 | { |
186 | struct arc *a; | |
187 | ||
188 | while ((a = s->ins) != NULL) | |
189 | freearc(nfa, a); | |
190 | while ((a = s->outs) != NULL) | |
191 | freearc(nfa, a); | |
192 | freestate(nfa, s); | |
193 | } | |
194 | ||
195 | /* | |
3ca4086b VS |
196 | - freestate - free a state, which has no in-arcs or out-arcs |
197 | ^ static VOID freestate(struct nfa *, struct state *); | |
48bf5def | 198 | */ |
3ca4086b VS |
199 | static VOID |
200 | freestate(nfa, s) | |
201 | struct nfa *nfa; | |
202 | struct state *s; | |
48bf5def RN |
203 | { |
204 | assert(s != NULL); | |
205 | assert(s->nins == 0 && s->nouts == 0); | |
206 | ||
207 | s->no = FREESTATE; | |
208 | s->flag = 0; | |
209 | if (s->next != NULL) | |
210 | s->next->prev = s->prev; | |
3ca4086b | 211 | else { |
48bf5def RN |
212 | assert(s == nfa->slast); |
213 | nfa->slast = s->prev; | |
214 | } | |
215 | if (s->prev != NULL) | |
216 | s->prev->next = s->next; | |
3ca4086b | 217 | else { |
48bf5def RN |
218 | assert(s == nfa->states); |
219 | nfa->states = s->next; | |
220 | } | |
221 | s->prev = NULL; | |
3ca4086b | 222 | s->next = nfa->free; /* don't delete it, put it on the free list */ |
48bf5def RN |
223 | nfa->free = s; |
224 | } | |
225 | ||
226 | /* | |
3ca4086b VS |
227 | - destroystate - really get rid of an already-freed state |
228 | ^ static VOID destroystate(struct nfa *, struct state *); | |
48bf5def | 229 | */ |
3ca4086b VS |
230 | static VOID |
231 | destroystate(nfa, s) | |
232 | struct nfa *nfa; | |
233 | struct state *s; | |
48bf5def RN |
234 | { |
235 | struct arcbatch *ab; | |
236 | struct arcbatch *abnext; | |
237 | ||
238 | assert(s->no == FREESTATE); | |
3ca4086b | 239 | for (ab = s->oas.next; ab != NULL; ab = abnext) { |
48bf5def RN |
240 | abnext = ab->next; |
241 | FREE(ab); | |
242 | } | |
243 | s->ins = NULL; | |
244 | s->outs = NULL; | |
245 | s->next = NULL; | |
246 | FREE(s); | |
247 | } | |
248 | ||
249 | /* | |
3ca4086b VS |
250 | - newarc - set up a new arc within an NFA |
251 | ^ static VOID newarc(struct nfa *, int, pcolor, struct state *, | |
252 | ^ struct state *); | |
48bf5def | 253 | */ |
3ca4086b VS |
254 | static VOID |
255 | newarc(nfa, t, co, from, to) | |
256 | struct nfa *nfa; | |
257 | int t; | |
258 | pcolor co; | |
259 | struct state *from; | |
260 | struct state *to; | |
48bf5def RN |
261 | { |
262 | struct arc *a; | |
263 | ||
264 | assert(from != NULL && to != NULL); | |
265 | ||
266 | /* check for duplicates */ | |
267 | for (a = from->outs; a != NULL; a = a->outchain) | |
268 | if (a->to == to && a->co == co && a->type == t) | |
269 | return; | |
270 | ||
271 | a = allocarc(nfa, from); | |
272 | if (NISERR()) | |
273 | return; | |
274 | assert(a != NULL); | |
275 | ||
276 | a->type = t; | |
3ca4086b | 277 | a->co = (color)co; |
48bf5def RN |
278 | a->to = to; |
279 | a->from = from; | |
280 | ||
281 | /* | |
3ca4086b VS |
282 | * Put the new arc on the beginning, not the end, of the chains. |
283 | * Not only is this easier, it has the very useful side effect that | |
48bf5def RN |
284 | * deleting the most-recently-added arc is the cheapest case rather |
285 | * than the most expensive one. | |
286 | */ | |
287 | a->inchain = to->ins; | |
288 | to->ins = a; | |
289 | a->outchain = from->outs; | |
290 | from->outs = a; | |
291 | ||
292 | from->nouts++; | |
293 | to->nins++; | |
294 | ||
295 | if (COLORED(a) && nfa->parent == NULL) | |
296 | colorchain(nfa->cm, a); | |
297 | ||
298 | return; | |
299 | } | |
300 | ||
301 | /* | |
3ca4086b VS |
302 | - allocarc - allocate a new out-arc within a state |
303 | ^ static struct arc *allocarc(struct nfa *, struct state *); | |
48bf5def | 304 | */ |
3ca4086b VS |
305 | static struct arc * /* NULL for failure */ |
306 | allocarc(nfa, s) | |
307 | struct nfa *nfa; | |
308 | struct state *s; | |
48bf5def RN |
309 | { |
310 | struct arc *a; | |
311 | struct arcbatch *new; | |
3ca4086b | 312 | int i; |
48bf5def RN |
313 | |
314 | /* shortcut */ | |
3ca4086b | 315 | if (s->free == NULL && s->noas < ABSIZE) { |
48bf5def RN |
316 | a = &s->oas.a[s->noas]; |
317 | s->noas++; | |
318 | return a; | |
319 | } | |
320 | ||
321 | /* if none at hand, get more */ | |
3ca4086b VS |
322 | if (s->free == NULL) { |
323 | new = (struct arcbatch *)MALLOC(sizeof(struct arcbatch)); | |
324 | if (new == NULL) { | |
48bf5def RN |
325 | NERR(REG_ESPACE); |
326 | return NULL; | |
327 | } | |
328 | new->next = s->oas.next; | |
329 | s->oas.next = new; | |
330 | ||
3ca4086b | 331 | for (i = 0; i < ABSIZE; i++) { |
48bf5def | 332 | new->a[i].type = 0; |
3ca4086b | 333 | new->a[i].freechain = &new->a[i+1]; |
48bf5def | 334 | } |
3ca4086b | 335 | new->a[ABSIZE-1].freechain = NULL; |
48bf5def RN |
336 | s->free = &new->a[0]; |
337 | } | |
338 | assert(s->free != NULL); | |
339 | ||
340 | a = s->free; | |
341 | s->free = a->freechain; | |
342 | return a; | |
343 | } | |
344 | ||
345 | /* | |
3ca4086b VS |
346 | - freearc - free an arc |
347 | ^ static VOID freearc(struct nfa *, struct arc *); | |
48bf5def | 348 | */ |
3ca4086b VS |
349 | static VOID |
350 | freearc(nfa, victim) | |
351 | struct nfa *nfa; | |
352 | struct arc *victim; | |
48bf5def RN |
353 | { |
354 | struct state *from = victim->from; | |
355 | struct state *to = victim->to; | |
356 | struct arc *a; | |
357 | ||
358 | assert(victim->type != 0); | |
359 | ||
360 | /* take it off color chain if necessary */ | |
361 | if (COLORED(victim) && nfa->parent == NULL) | |
362 | uncolorchain(nfa->cm, victim); | |
363 | ||
364 | /* take it off source's out-chain */ | |
365 | assert(from != NULL); | |
366 | assert(from->outs != NULL); | |
367 | a = from->outs; | |
3ca4086b | 368 | if (a == victim) /* simple case: first in chain */ |
48bf5def | 369 | from->outs = victim->outchain; |
3ca4086b | 370 | else { |
48bf5def RN |
371 | for (; a != NULL && a->outchain != victim; a = a->outchain) |
372 | continue; | |
373 | assert(a != NULL); | |
374 | a->outchain = victim->outchain; | |
375 | } | |
376 | from->nouts--; | |
377 | ||
378 | /* take it off target's in-chain */ | |
379 | assert(to != NULL); | |
380 | assert(to->ins != NULL); | |
381 | a = to->ins; | |
3ca4086b | 382 | if (a == victim) /* simple case: first in chain */ |
48bf5def | 383 | to->ins = victim->inchain; |
3ca4086b | 384 | else { |
48bf5def RN |
385 | for (; a != NULL && a->inchain != victim; a = a->inchain) |
386 | continue; | |
387 | assert(a != NULL); | |
388 | a->inchain = victim->inchain; | |
389 | } | |
390 | to->nins--; | |
391 | ||
392 | /* clean up and place on free list */ | |
393 | victim->type = 0; | |
394 | victim->from = NULL; /* precautions... */ | |
395 | victim->to = NULL; | |
396 | victim->inchain = NULL; | |
397 | victim->outchain = NULL; | |
398 | victim->freechain = from->free; | |
399 | from->free = victim; | |
400 | } | |
401 | ||
402 | /* | |
3ca4086b | 403 | - findarc - find arc, if any, from given source with given type and color |
48bf5def | 404 | * If there is more than one such arc, the result is random. |
3ca4086b | 405 | ^ static struct arc *findarc(struct state *, int, pcolor); |
48bf5def RN |
406 | */ |
407 | static struct arc * | |
3ca4086b VS |
408 | findarc(s, type, co) |
409 | struct state *s; | |
410 | int type; | |
411 | pcolor co; | |
48bf5def RN |
412 | { |
413 | struct arc *a; | |
414 | ||
415 | for (a = s->outs; a != NULL; a = a->outchain) | |
416 | if (a->type == type && a->co == co) | |
417 | return a; | |
418 | return NULL; | |
419 | } | |
420 | ||
421 | /* | |
3ca4086b VS |
422 | - cparc - allocate a new arc within an NFA, copying details from old one |
423 | ^ static VOID cparc(struct nfa *, struct arc *, struct state *, | |
424 | ^ struct state *); | |
48bf5def | 425 | */ |
3ca4086b VS |
426 | static VOID |
427 | cparc(nfa, oa, from, to) | |
428 | struct nfa *nfa; | |
429 | struct arc *oa; | |
430 | struct state *from; | |
431 | struct state *to; | |
48bf5def RN |
432 | { |
433 | newarc(nfa, oa->type, oa->co, from, to); | |
434 | } | |
435 | ||
436 | /* | |
3ca4086b | 437 | - moveins - move all in arcs of a state to another state |
48bf5def RN |
438 | * You might think this could be done better by just updating the |
439 | * existing arcs, and you would be right if it weren't for the desire | |
440 | * for duplicate suppression, which makes it easier to just make new | |
441 | * ones to exploit the suppression built into newarc. | |
3ca4086b | 442 | ^ static VOID moveins(struct nfa *, struct state *, struct state *); |
48bf5def | 443 | */ |
3ca4086b VS |
444 | static VOID |
445 | moveins(nfa, old, new) | |
446 | struct nfa *nfa; | |
447 | struct state *old; | |
448 | struct state *new; | |
48bf5def RN |
449 | { |
450 | struct arc *a; | |
451 | ||
452 | assert(old != new); | |
453 | ||
3ca4086b | 454 | while ((a = old->ins) != NULL) { |
48bf5def RN |
455 | cparc(nfa, a, a->from, new); |
456 | freearc(nfa, a); | |
457 | } | |
458 | assert(old->nins == 0); | |
459 | assert(old->ins == NULL); | |
460 | } | |
461 | ||
462 | /* | |
3ca4086b VS |
463 | - copyins - copy all in arcs of a state to another state |
464 | ^ static VOID copyins(struct nfa *, struct state *, struct state *); | |
48bf5def | 465 | */ |
3ca4086b VS |
466 | static VOID |
467 | copyins(nfa, old, new) | |
468 | struct nfa *nfa; | |
469 | struct state *old; | |
470 | struct state *new; | |
48bf5def RN |
471 | { |
472 | struct arc *a; | |
473 | ||
474 | assert(old != new); | |
475 | ||
476 | for (a = old->ins; a != NULL; a = a->inchain) | |
477 | cparc(nfa, a, a->from, new); | |
478 | } | |
479 | ||
480 | /* | |
3ca4086b VS |
481 | - moveouts - move all out arcs of a state to another state |
482 | ^ static VOID moveouts(struct nfa *, struct state *, struct state *); | |
48bf5def | 483 | */ |
3ca4086b VS |
484 | static VOID |
485 | moveouts(nfa, old, new) | |
486 | struct nfa *nfa; | |
487 | struct state *old; | |
488 | struct state *new; | |
48bf5def RN |
489 | { |
490 | struct arc *a; | |
491 | ||
492 | assert(old != new); | |
493 | ||
3ca4086b | 494 | while ((a = old->outs) != NULL) { |
48bf5def RN |
495 | cparc(nfa, a, new, a->to); |
496 | freearc(nfa, a); | |
497 | } | |
498 | } | |
499 | ||
500 | /* | |
3ca4086b VS |
501 | - copyouts - copy all out arcs of a state to another state |
502 | ^ static VOID copyouts(struct nfa *, struct state *, struct state *); | |
48bf5def | 503 | */ |
3ca4086b VS |
504 | static VOID |
505 | copyouts(nfa, old, new) | |
506 | struct nfa *nfa; | |
507 | struct state *old; | |
508 | struct state *new; | |
48bf5def RN |
509 | { |
510 | struct arc *a; | |
511 | ||
512 | assert(old != new); | |
513 | ||
514 | for (a = old->outs; a != NULL; a = a->outchain) | |
515 | cparc(nfa, a, new, a->to); | |
516 | } | |
517 | ||
518 | /* | |
3ca4086b VS |
519 | - cloneouts - copy out arcs of a state to another state pair, modifying type |
520 | ^ static VOID cloneouts(struct nfa *, struct state *, struct state *, | |
521 | ^ struct state *, int); | |
48bf5def | 522 | */ |
3ca4086b VS |
523 | static VOID |
524 | cloneouts(nfa, old, from, to, type) | |
525 | struct nfa *nfa; | |
526 | struct state *old; | |
527 | struct state *from; | |
528 | struct state *to; | |
529 | int type; | |
48bf5def RN |
530 | { |
531 | struct arc *a; | |
532 | ||
533 | assert(old != from); | |
534 | ||
535 | for (a = old->outs; a != NULL; a = a->outchain) | |
536 | newarc(nfa, type, a->co, from, to); | |
537 | } | |
538 | ||
539 | /* | |
3ca4086b | 540 | - delsub - delete a sub-NFA, updating subre pointers if necessary |
48bf5def RN |
541 | * This uses a recursive traversal of the sub-NFA, marking already-seen |
542 | * states using their tmp pointer. | |
3ca4086b | 543 | ^ static VOID delsub(struct nfa *, struct state *, struct state *); |
48bf5def | 544 | */ |
3ca4086b VS |
545 | static VOID |
546 | delsub(nfa, lp, rp) | |
547 | struct nfa *nfa; | |
548 | struct state *lp; /* the sub-NFA goes from here... */ | |
549 | struct state *rp; /* ...to here, *not* inclusive */ | |
48bf5def RN |
550 | { |
551 | assert(lp != rp); | |
552 | ||
3ca4086b | 553 | rp->tmp = rp; /* mark end */ |
48bf5def RN |
554 | |
555 | deltraverse(nfa, lp, lp); | |
556 | assert(lp->nouts == 0 && rp->nins == 0); /* did the job */ | |
3ca4086b | 557 | assert(lp->no != FREESTATE && rp->no != FREESTATE); /* no more */ |
48bf5def | 558 | |
3ca4086b VS |
559 | rp->tmp = NULL; /* unmark end */ |
560 | lp->tmp = NULL; /* and begin, marked by deltraverse */ | |
48bf5def RN |
561 | } |
562 | ||
563 | /* | |
3ca4086b | 564 | - deltraverse - the recursive heart of delsub |
48bf5def | 565 | * This routine's basic job is to destroy all out-arcs of the state. |
3ca4086b | 566 | ^ static VOID deltraverse(struct nfa *, struct state *, struct state *); |
48bf5def | 567 | */ |
3ca4086b VS |
568 | static VOID |
569 | deltraverse(nfa, leftend, s) | |
570 | struct nfa *nfa; | |
571 | struct state *leftend; | |
572 | struct state *s; | |
48bf5def RN |
573 | { |
574 | struct arc *a; | |
575 | struct state *to; | |
576 | ||
577 | if (s->nouts == 0) | |
3ca4086b | 578 | return; /* nothing to do */ |
48bf5def | 579 | if (s->tmp != NULL) |
3ca4086b | 580 | return; /* already in progress */ |
48bf5def | 581 | |
3ca4086b | 582 | s->tmp = s; /* mark as in progress */ |
48bf5def | 583 | |
3ca4086b | 584 | while ((a = s->outs) != NULL) { |
48bf5def RN |
585 | to = a->to; |
586 | deltraverse(nfa, leftend, to); | |
587 | assert(to->nouts == 0 || to->tmp != NULL); | |
588 | freearc(nfa, a); | |
3ca4086b | 589 | if (to->nins == 0 && to->tmp == NULL) { |
48bf5def RN |
590 | assert(to->nouts == 0); |
591 | freestate(nfa, to); | |
592 | } | |
593 | } | |
594 | ||
3ca4086b VS |
595 | assert(s->no != FREESTATE); /* we're still here */ |
596 | assert(s == leftend || s->nins != 0); /* and still reachable */ | |
48bf5def RN |
597 | assert(s->nouts == 0); /* but have no outarcs */ |
598 | ||
3ca4086b | 599 | s->tmp = NULL; /* we're done here */ |
48bf5def RN |
600 | } |
601 | ||
602 | /* | |
3ca4086b | 603 | - dupnfa - duplicate sub-NFA |
48bf5def RN |
604 | * Another recursive traversal, this time using tmp to point to duplicates |
605 | * as well as mark already-seen states. (You knew there was a reason why | |
606 | * it's a state pointer, didn't you? :-)) | |
3ca4086b VS |
607 | ^ static VOID dupnfa(struct nfa *, struct state *, struct state *, |
608 | ^ struct state *, struct state *); | |
48bf5def | 609 | */ |
3ca4086b VS |
610 | static VOID |
611 | dupnfa(nfa, start, stop, from, to) | |
612 | struct nfa *nfa; | |
613 | struct state *start; /* duplicate of subNFA starting here */ | |
614 | struct state *stop; /* and stopping here */ | |
615 | struct state *from; /* stringing duplicate from here */ | |
616 | struct state *to; /* to here */ | |
48bf5def | 617 | { |
3ca4086b | 618 | if (start == stop) { |
48bf5def RN |
619 | newarc(nfa, EMPTY, 0, from, to); |
620 | return; | |
621 | } | |
622 | ||
623 | stop->tmp = to; | |
624 | duptraverse(nfa, start, from); | |
625 | /* done, except for clearing out the tmp pointers */ | |
626 | ||
627 | stop->tmp = NULL; | |
628 | cleartraverse(nfa, start); | |
629 | } | |
630 | ||
631 | /* | |
3ca4086b VS |
632 | - duptraverse - recursive heart of dupnfa |
633 | ^ static VOID duptraverse(struct nfa *, struct state *, struct state *); | |
48bf5def | 634 | */ |
3ca4086b VS |
635 | static VOID |
636 | duptraverse(nfa, s, stmp) | |
637 | struct nfa *nfa; | |
638 | struct state *s; | |
639 | struct state *stmp; /* s's duplicate, or NULL */ | |
48bf5def RN |
640 | { |
641 | struct arc *a; | |
642 | ||
643 | if (s->tmp != NULL) | |
3ca4086b | 644 | return; /* already done */ |
48bf5def RN |
645 | |
646 | s->tmp = (stmp == NULL) ? newstate(nfa) : stmp; | |
3ca4086b | 647 | if (s->tmp == NULL) { |
48bf5def RN |
648 | assert(NISERR()); |
649 | return; | |
650 | } | |
651 | ||
3ca4086b VS |
652 | for (a = s->outs; a != NULL && !NISERR(); a = a->outchain) { |
653 | duptraverse(nfa, a->to, (struct state *)NULL); | |
48bf5def RN |
654 | assert(a->to->tmp != NULL); |
655 | cparc(nfa, a, s->tmp, a->to->tmp); | |
656 | } | |
657 | } | |
658 | ||
659 | /* | |
3ca4086b VS |
660 | - cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set |
661 | ^ static VOID cleartraverse(struct nfa *, struct state *); | |
48bf5def | 662 | */ |
3ca4086b VS |
663 | static VOID |
664 | cleartraverse(nfa, s) | |
665 | struct nfa *nfa; | |
666 | struct state *s; | |
48bf5def RN |
667 | { |
668 | struct arc *a; | |
669 | ||
670 | if (s->tmp == NULL) | |
671 | return; | |
672 | s->tmp = NULL; | |
673 | ||
674 | for (a = s->outs; a != NULL; a = a->outchain) | |
675 | cleartraverse(nfa, a->to); | |
676 | } | |
677 | ||
678 | /* | |
3ca4086b VS |
679 | - specialcolors - fill in special colors for an NFA |
680 | ^ static VOID specialcolors(struct nfa *); | |
48bf5def | 681 | */ |
3ca4086b VS |
682 | static VOID |
683 | specialcolors(nfa) | |
684 | struct nfa *nfa; | |
48bf5def RN |
685 | { |
686 | /* false colors for BOS, BOL, EOS, EOL */ | |
3ca4086b | 687 | if (nfa->parent == NULL) { |
48bf5def RN |
688 | nfa->bos[0] = pseudocolor(nfa->cm); |
689 | nfa->bos[1] = pseudocolor(nfa->cm); | |
690 | nfa->eos[0] = pseudocolor(nfa->cm); | |
691 | nfa->eos[1] = pseudocolor(nfa->cm); | |
3ca4086b | 692 | } else { |
48bf5def RN |
693 | assert(nfa->parent->bos[0] != COLORLESS); |
694 | nfa->bos[0] = nfa->parent->bos[0]; | |
695 | assert(nfa->parent->bos[1] != COLORLESS); | |
696 | nfa->bos[1] = nfa->parent->bos[1]; | |
697 | assert(nfa->parent->eos[0] != COLORLESS); | |
698 | nfa->eos[0] = nfa->parent->eos[0]; | |
699 | assert(nfa->parent->eos[1] != COLORLESS); | |
700 | nfa->eos[1] = nfa->parent->eos[1]; | |
701 | } | |
702 | } | |
703 | ||
704 | /* | |
3ca4086b VS |
705 | - optimize - optimize an NFA |
706 | ^ static long optimize(struct nfa *, FILE *); | |
48bf5def | 707 | */ |
3ca4086b VS |
708 | static long /* re_info bits */ |
709 | optimize(nfa, f) | |
710 | struct nfa *nfa; | |
711 | FILE *f; /* for debug output; NULL none */ | |
48bf5def | 712 | { |
3ca4086b | 713 | int verbose = (f != NULL) ? 1 : 0; |
48bf5def RN |
714 | |
715 | if (verbose) | |
716 | fprintf(f, "\ninitial cleanup:\n"); | |
3ca4086b | 717 | cleanup(nfa); /* may simplify situation */ |
48bf5def RN |
718 | if (verbose) |
719 | dumpnfa(nfa, f); | |
720 | if (verbose) | |
721 | fprintf(f, "\nempties:\n"); | |
3ca4086b | 722 | fixempties(nfa, f); /* get rid of EMPTY arcs */ |
48bf5def RN |
723 | if (verbose) |
724 | fprintf(f, "\nconstraints:\n"); | |
3ca4086b VS |
725 | pullback(nfa, f); /* pull back constraints backward */ |
726 | pushfwd(nfa, f); /* push fwd constraints forward */ | |
48bf5def RN |
727 | if (verbose) |
728 | fprintf(f, "\nfinal cleanup:\n"); | |
3ca4086b VS |
729 | cleanup(nfa); /* final tidying */ |
730 | return analyze(nfa); /* and analysis */ | |
48bf5def RN |
731 | } |
732 | ||
733 | /* | |
3ca4086b VS |
734 | - pullback - pull back constraints backward to (with luck) eliminate them |
735 | ^ static VOID pullback(struct nfa *, FILE *); | |
48bf5def | 736 | */ |
3ca4086b VS |
737 | static VOID |
738 | pullback(nfa, f) | |
739 | struct nfa *nfa; | |
740 | FILE *f; /* for debug output; NULL none */ | |
48bf5def RN |
741 | { |
742 | struct state *s; | |
743 | struct state *nexts; | |
744 | struct arc *a; | |
745 | struct arc *nexta; | |
3ca4086b | 746 | int progress; |
48bf5def RN |
747 | |
748 | /* find and pull until there are no more */ | |
3ca4086b | 749 | do { |
48bf5def | 750 | progress = 0; |
3ca4086b | 751 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
48bf5def | 752 | nexts = s->next; |
3ca4086b | 753 | for (a = s->outs; a != NULL && !NISERR(); a = nexta) { |
48bf5def RN |
754 | nexta = a->outchain; |
755 | if (a->type == '^' || a->type == BEHIND) | |
756 | if (pull(nfa, a)) | |
757 | progress = 1; | |
758 | assert(nexta == NULL || s->no != FREESTATE); | |
759 | } | |
760 | } | |
761 | if (progress && f != NULL) | |
762 | dumpnfa(nfa, f); | |
763 | } while (progress && !NISERR()); | |
764 | if (NISERR()) | |
765 | return; | |
766 | ||
3ca4086b | 767 | for (a = nfa->pre->outs; a != NULL; a = nexta) { |
48bf5def | 768 | nexta = a->outchain; |
3ca4086b | 769 | if (a->type == '^') { |
48bf5def RN |
770 | assert(a->co == 0 || a->co == 1); |
771 | newarc(nfa, PLAIN, nfa->bos[a->co], a->from, a->to); | |
772 | freearc(nfa, a); | |
773 | } | |
774 | } | |
775 | } | |
776 | ||
777 | /* | |
3ca4086b | 778 | - pull - pull a back constraint backward past its source state |
48bf5def RN |
779 | * A significant property of this function is that it deletes at most |
780 | * one state -- the constraint's from state -- and only if the constraint | |
781 | * was that state's last outarc. | |
3ca4086b | 782 | ^ static int pull(struct nfa *, struct arc *); |
48bf5def | 783 | */ |
3ca4086b VS |
784 | static int /* 0 couldn't, 1 could */ |
785 | pull(nfa, con) | |
786 | struct nfa *nfa; | |
787 | struct arc *con; | |
48bf5def RN |
788 | { |
789 | struct state *from = con->from; | |
790 | struct state *to = con->to; | |
791 | struct arc *a; | |
792 | struct arc *nexta; | |
793 | struct state *s; | |
794 | ||
3ca4086b | 795 | if (from == to) { /* circular constraint is pointless */ |
48bf5def RN |
796 | freearc(nfa, con); |
797 | return 1; | |
798 | } | |
3ca4086b | 799 | if (from->flag) /* can't pull back beyond start */ |
48bf5def | 800 | return 0; |
3ca4086b | 801 | if (from->nins == 0) { /* unreachable */ |
48bf5def RN |
802 | freearc(nfa, con); |
803 | return 1; | |
804 | } | |
805 | ||
806 | /* first, clone from state if necessary to avoid other outarcs */ | |
3ca4086b | 807 | if (from->nouts > 1) { |
48bf5def RN |
808 | s = newstate(nfa); |
809 | if (NISERR()) | |
810 | return 0; | |
811 | assert(to != from); /* con is not an inarc */ | |
3ca4086b VS |
812 | copyins(nfa, from, s); /* duplicate inarcs */ |
813 | cparc(nfa, con, s, to); /* move constraint arc */ | |
48bf5def RN |
814 | freearc(nfa, con); |
815 | from = s; | |
816 | con = from->outs; | |
817 | } | |
818 | assert(from->nouts == 1); | |
819 | ||
820 | /* propagate the constraint into the from state's inarcs */ | |
3ca4086b | 821 | for (a = from->ins; a != NULL; a = nexta) { |
48bf5def | 822 | nexta = a->inchain; |
3ca4086b VS |
823 | switch (combine(con, a)) { |
824 | case INCOMPATIBLE: /* destroy the arc */ | |
825 | freearc(nfa, a); | |
826 | break; | |
827 | case SATISFIED: /* no action needed */ | |
828 | break; | |
829 | case COMPATIBLE: /* swap the two arcs, more or less */ | |
830 | s = newstate(nfa); | |
831 | if (NISERR()) | |
832 | return 0; | |
833 | cparc(nfa, a, s, to); /* anticipate move */ | |
834 | cparc(nfa, con, a->from, s); | |
835 | if (NISERR()) | |
836 | return 0; | |
837 | freearc(nfa, a); | |
838 | break; | |
839 | default: | |
840 | assert(NOTREACHED); | |
841 | break; | |
48bf5def RN |
842 | } |
843 | } | |
844 | ||
845 | /* remaining inarcs, if any, incorporate the constraint */ | |
846 | moveins(nfa, from, to); | |
847 | dropstate(nfa, from); /* will free the constraint */ | |
848 | return 1; | |
849 | } | |
850 | ||
851 | /* | |
3ca4086b VS |
852 | - pushfwd - push forward constraints forward to (with luck) eliminate them |
853 | ^ static VOID pushfwd(struct nfa *, FILE *); | |
48bf5def | 854 | */ |
3ca4086b VS |
855 | static VOID |
856 | pushfwd(nfa, f) | |
857 | struct nfa *nfa; | |
858 | FILE *f; /* for debug output; NULL none */ | |
48bf5def RN |
859 | { |
860 | struct state *s; | |
861 | struct state *nexts; | |
862 | struct arc *a; | |
863 | struct arc *nexta; | |
3ca4086b | 864 | int progress; |
48bf5def RN |
865 | |
866 | /* find and push until there are no more */ | |
3ca4086b | 867 | do { |
48bf5def | 868 | progress = 0; |
3ca4086b | 869 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
48bf5def | 870 | nexts = s->next; |
3ca4086b | 871 | for (a = s->ins; a != NULL && !NISERR(); a = nexta) { |
48bf5def RN |
872 | nexta = a->inchain; |
873 | if (a->type == '$' || a->type == AHEAD) | |
874 | if (push(nfa, a)) | |
875 | progress = 1; | |
876 | assert(nexta == NULL || s->no != FREESTATE); | |
877 | } | |
878 | } | |
879 | if (progress && f != NULL) | |
880 | dumpnfa(nfa, f); | |
881 | } while (progress && !NISERR()); | |
882 | if (NISERR()) | |
883 | return; | |
884 | ||
3ca4086b | 885 | for (a = nfa->post->ins; a != NULL; a = nexta) { |
48bf5def | 886 | nexta = a->inchain; |
3ca4086b | 887 | if (a->type == '$') { |
48bf5def RN |
888 | assert(a->co == 0 || a->co == 1); |
889 | newarc(nfa, PLAIN, nfa->eos[a->co], a->from, a->to); | |
890 | freearc(nfa, a); | |
891 | } | |
892 | } | |
893 | } | |
894 | ||
895 | /* | |
3ca4086b | 896 | - push - push a forward constraint forward past its destination state |
48bf5def RN |
897 | * A significant property of this function is that it deletes at most |
898 | * one state -- the constraint's to state -- and only if the constraint | |
899 | * was that state's last inarc. | |
3ca4086b | 900 | ^ static int push(struct nfa *, struct arc *); |
48bf5def | 901 | */ |
3ca4086b VS |
902 | static int /* 0 couldn't, 1 could */ |
903 | push(nfa, con) | |
904 | struct nfa *nfa; | |
905 | struct arc *con; | |
48bf5def RN |
906 | { |
907 | struct state *from = con->from; | |
908 | struct state *to = con->to; | |
909 | struct arc *a; | |
910 | struct arc *nexta; | |
911 | struct state *s; | |
912 | ||
3ca4086b | 913 | if (to == from) { /* circular constraint is pointless */ |
48bf5def RN |
914 | freearc(nfa, con); |
915 | return 1; | |
916 | } | |
3ca4086b | 917 | if (to->flag) /* can't push forward beyond end */ |
48bf5def | 918 | return 0; |
3ca4086b | 919 | if (to->nouts == 0) { /* dead end */ |
48bf5def RN |
920 | freearc(nfa, con); |
921 | return 1; | |
922 | } | |
923 | ||
924 | /* first, clone to state if necessary to avoid other inarcs */ | |
3ca4086b | 925 | if (to->nins > 1) { |
48bf5def RN |
926 | s = newstate(nfa); |
927 | if (NISERR()) | |
928 | return 0; | |
3ca4086b VS |
929 | copyouts(nfa, to, s); /* duplicate outarcs */ |
930 | cparc(nfa, con, from, s); /* move constraint */ | |
48bf5def RN |
931 | freearc(nfa, con); |
932 | to = s; | |
933 | con = to->ins; | |
934 | } | |
935 | assert(to->nins == 1); | |
936 | ||
937 | /* propagate the constraint into the to state's outarcs */ | |
3ca4086b | 938 | for (a = to->outs; a != NULL; a = nexta) { |
48bf5def | 939 | nexta = a->outchain; |
3ca4086b VS |
940 | switch (combine(con, a)) { |
941 | case INCOMPATIBLE: /* destroy the arc */ | |
942 | freearc(nfa, a); | |
943 | break; | |
944 | case SATISFIED: /* no action needed */ | |
945 | break; | |
946 | case COMPATIBLE: /* swap the two arcs, more or less */ | |
947 | s = newstate(nfa); | |
948 | if (NISERR()) | |
949 | return 0; | |
950 | cparc(nfa, con, s, a->to); /* anticipate move */ | |
951 | cparc(nfa, a, from, s); | |
952 | if (NISERR()) | |
953 | return 0; | |
954 | freearc(nfa, a); | |
955 | break; | |
956 | default: | |
957 | assert(NOTREACHED); | |
958 | break; | |
48bf5def RN |
959 | } |
960 | } | |
961 | ||
962 | /* remaining outarcs, if any, incorporate the constraint */ | |
963 | moveouts(nfa, to, from); | |
3ca4086b | 964 | dropstate(nfa, to); /* will free the constraint */ |
48bf5def RN |
965 | return 1; |
966 | } | |
967 | ||
968 | /* | |
3ca4086b VS |
969 | - combine - constraint lands on an arc, what happens? |
970 | ^ #def INCOMPATIBLE 1 // destroys arc | |
971 | ^ #def SATISFIED 2 // constraint satisfied | |
972 | ^ #def COMPATIBLE 3 // compatible but not satisfied yet | |
973 | ^ static int combine(struct arc *, struct arc *); | |
48bf5def | 974 | */ |
0f0fd26d JS |
975 | |
976 | /* FIXME Required for CW 8 on Mac since it's not in limits.h */ | |
977 | #ifndef __CHAR_BIT__ | |
978 | #define __CHAR_BIT__ 8 | |
979 | #endif | |
980 | ||
981 | ||
48bf5def | 982 | static int |
3ca4086b VS |
983 | combine(con, a) |
984 | struct arc *con; | |
985 | struct arc *a; | |
48bf5def | 986 | { |
3ca4086b VS |
987 | # define CA(ct,at) (((ct)<<CHAR_BIT) | (at)) |
988 | ||
989 | switch (CA(con->type, a->type)) { | |
990 | case CA('^', PLAIN): /* newlines are handled separately */ | |
991 | case CA('$', PLAIN): | |
992 | return INCOMPATIBLE; | |
993 | break; | |
994 | case CA(AHEAD, PLAIN): /* color constraints meet colors */ | |
995 | case CA(BEHIND, PLAIN): | |
996 | if (con->co == a->co) | |
997 | return SATISFIED; | |
998 | return INCOMPATIBLE; | |
999 | break; | |
1000 | case CA('^', '^'): /* collision, similar constraints */ | |
1001 | case CA('$', '$'): | |
1002 | case CA(AHEAD, AHEAD): | |
1003 | case CA(BEHIND, BEHIND): | |
1004 | if (con->co == a->co) /* true duplication */ | |
1005 | return SATISFIED; | |
1006 | return INCOMPATIBLE; | |
1007 | break; | |
1008 | case CA('^', BEHIND): /* collision, dissimilar constraints */ | |
1009 | case CA(BEHIND, '^'): | |
1010 | case CA('$', AHEAD): | |
1011 | case CA(AHEAD, '$'): | |
1012 | return INCOMPATIBLE; | |
1013 | break; | |
1014 | case CA('^', '$'): /* constraints passing each other */ | |
1015 | case CA('^', AHEAD): | |
1016 | case CA(BEHIND, '$'): | |
1017 | case CA(BEHIND, AHEAD): | |
1018 | case CA('$', '^'): | |
1019 | case CA('$', BEHIND): | |
1020 | case CA(AHEAD, '^'): | |
1021 | case CA(AHEAD, BEHIND): | |
1022 | case CA('^', LACON): | |
1023 | case CA(BEHIND, LACON): | |
1024 | case CA('$', LACON): | |
1025 | case CA(AHEAD, LACON): | |
1026 | return COMPATIBLE; | |
1027 | break; | |
48bf5def RN |
1028 | } |
1029 | assert(NOTREACHED); | |
1030 | return INCOMPATIBLE; /* for benefit of blind compilers */ | |
1031 | } | |
1032 | ||
1033 | /* | |
3ca4086b VS |
1034 | - fixempties - get rid of EMPTY arcs |
1035 | ^ static VOID fixempties(struct nfa *, FILE *); | |
48bf5def | 1036 | */ |
3ca4086b VS |
1037 | static VOID |
1038 | fixempties(nfa, f) | |
1039 | struct nfa *nfa; | |
1040 | FILE *f; /* for debug output; NULL none */ | |
48bf5def RN |
1041 | { |
1042 | struct state *s; | |
1043 | struct state *nexts; | |
1044 | struct arc *a; | |
1045 | struct arc *nexta; | |
3ca4086b | 1046 | int progress; |
48bf5def RN |
1047 | |
1048 | /* find and eliminate empties until there are no more */ | |
3ca4086b | 1049 | do { |
48bf5def | 1050 | progress = 0; |
3ca4086b | 1051 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
48bf5def | 1052 | nexts = s->next; |
3ca4086b | 1053 | for (a = s->outs; a != NULL && !NISERR(); a = nexta) { |
48bf5def RN |
1054 | nexta = a->outchain; |
1055 | if (a->type == EMPTY && unempty(nfa, a)) | |
1056 | progress = 1; | |
1057 | assert(nexta == NULL || s->no != FREESTATE); | |
1058 | } | |
1059 | } | |
1060 | if (progress && f != NULL) | |
1061 | dumpnfa(nfa, f); | |
1062 | } while (progress && !NISERR()); | |
1063 | } | |
1064 | ||
1065 | /* | |
3ca4086b | 1066 | - unempty - optimize out an EMPTY arc, if possible |
48bf5def RN |
1067 | * Actually, as it stands this function always succeeds, but the return |
1068 | * value is kept with an eye on possible future changes. | |
3ca4086b | 1069 | ^ static int unempty(struct nfa *, struct arc *); |
48bf5def | 1070 | */ |
3ca4086b VS |
1071 | static int /* 0 couldn't, 1 could */ |
1072 | unempty(nfa, a) | |
1073 | struct nfa *nfa; | |
1074 | struct arc *a; | |
48bf5def RN |
1075 | { |
1076 | struct state *from = a->from; | |
1077 | struct state *to = a->to; | |
3ca4086b | 1078 | int usefrom; /* work on from, as opposed to to? */ |
48bf5def RN |
1079 | |
1080 | assert(a->type == EMPTY); | |
1081 | assert(from != nfa->pre && to != nfa->post); | |
1082 | ||
3ca4086b | 1083 | if (from == to) { /* vacuous loop */ |
48bf5def RN |
1084 | freearc(nfa, a); |
1085 | return 1; | |
1086 | } | |
1087 | ||
1088 | /* decide which end to work on */ | |
3ca4086b | 1089 | usefrom = 1; /* default: attack from */ |
48bf5def RN |
1090 | if (from->nouts > to->nins) |
1091 | usefrom = 0; | |
3ca4086b | 1092 | else if (from->nouts == to->nins) { |
48bf5def RN |
1093 | /* decide on secondary issue: move/copy fewest arcs */ |
1094 | if (from->nins > to->nouts) | |
1095 | usefrom = 0; | |
1096 | } | |
3ca4086b | 1097 | |
48bf5def | 1098 | freearc(nfa, a); |
3ca4086b VS |
1099 | if (usefrom) { |
1100 | if (from->nouts == 0) { | |
48bf5def RN |
1101 | /* was the state's only outarc */ |
1102 | moveins(nfa, from, to); | |
1103 | freestate(nfa, from); | |
3ca4086b | 1104 | } else |
48bf5def | 1105 | copyins(nfa, from, to); |
3ca4086b VS |
1106 | } else { |
1107 | if (to->nins == 0) { | |
48bf5def RN |
1108 | /* was the state's only inarc */ |
1109 | moveouts(nfa, to, from); | |
1110 | freestate(nfa, to); | |
3ca4086b | 1111 | } else |
48bf5def RN |
1112 | copyouts(nfa, to, from); |
1113 | } | |
1114 | ||
1115 | return 1; | |
1116 | } | |
1117 | ||
1118 | /* | |
3ca4086b VS |
1119 | - cleanup - clean up NFA after optimizations |
1120 | ^ static VOID cleanup(struct nfa *); | |
48bf5def | 1121 | */ |
3ca4086b VS |
1122 | static VOID |
1123 | cleanup(nfa) | |
1124 | struct nfa *nfa; | |
48bf5def RN |
1125 | { |
1126 | struct state *s; | |
1127 | struct state *nexts; | |
3ca4086b | 1128 | int n; |
48bf5def RN |
1129 | |
1130 | /* clear out unreachable or dead-end states */ | |
1131 | /* use pre to mark reachable, then post to mark can-reach-post */ | |
3ca4086b | 1132 | markreachable(nfa, nfa->pre, (struct state *)NULL, nfa->pre); |
48bf5def | 1133 | markcanreach(nfa, nfa->post, nfa->pre, nfa->post); |
3ca4086b | 1134 | for (s = nfa->states; s != NULL; s = nexts) { |
48bf5def RN |
1135 | nexts = s->next; |
1136 | if (s->tmp != nfa->post && !s->flag) | |
1137 | dropstate(nfa, s); | |
1138 | } | |
1139 | assert(nfa->post->nins == 0 || nfa->post->tmp == nfa->post); | |
1140 | cleartraverse(nfa, nfa->pre); | |
1141 | assert(nfa->post->nins == 0 || nfa->post->tmp == NULL); | |
1142 | /* the nins==0 (final unreachable) case will be caught later */ | |
1143 | ||
1144 | /* renumber surviving states */ | |
1145 | n = 0; | |
1146 | for (s = nfa->states; s != NULL; s = s->next) | |
1147 | s->no = n++; | |
1148 | nfa->nstates = n; | |
1149 | } | |
1150 | ||
1151 | /* | |
3ca4086b VS |
1152 | - markreachable - recursive marking of reachable states |
1153 | ^ static VOID markreachable(struct nfa *, struct state *, struct state *, | |
1154 | ^ struct state *); | |
48bf5def | 1155 | */ |
3ca4086b VS |
1156 | static VOID |
1157 | markreachable(nfa, s, okay, mark) | |
1158 | struct nfa *nfa; | |
1159 | struct state *s; | |
1160 | struct state *okay; /* consider only states with this mark */ | |
1161 | struct state *mark; /* the value to mark with */ | |
48bf5def RN |
1162 | { |
1163 | struct arc *a; | |
1164 | ||
1165 | if (s->tmp != okay) | |
1166 | return; | |
1167 | s->tmp = mark; | |
1168 | ||
1169 | for (a = s->outs; a != NULL; a = a->outchain) | |
1170 | markreachable(nfa, a->to, okay, mark); | |
1171 | } | |
1172 | ||
1173 | /* | |
3ca4086b VS |
1174 | - markcanreach - recursive marking of states which can reach here |
1175 | ^ static VOID markcanreach(struct nfa *, struct state *, struct state *, | |
1176 | ^ struct state *); | |
48bf5def | 1177 | */ |
3ca4086b VS |
1178 | static VOID |
1179 | markcanreach(nfa, s, okay, mark) | |
1180 | struct nfa *nfa; | |
1181 | struct state *s; | |
1182 | struct state *okay; /* consider only states with this mark */ | |
1183 | struct state *mark; /* the value to mark with */ | |
48bf5def RN |
1184 | { |
1185 | struct arc *a; | |
1186 | ||
1187 | if (s->tmp != okay) | |
1188 | return; | |
1189 | s->tmp = mark; | |
1190 | ||
1191 | for (a = s->ins; a != NULL; a = a->inchain) | |
1192 | markcanreach(nfa, a->from, okay, mark); | |
1193 | } | |
1194 | ||
1195 | /* | |
3ca4086b VS |
1196 | - analyze - ascertain potentially-useful facts about an optimized NFA |
1197 | ^ static long analyze(struct nfa *); | |
48bf5def | 1198 | */ |
3ca4086b VS |
1199 | static long /* re_info bits to be ORed in */ |
1200 | analyze(nfa) | |
1201 | struct nfa *nfa; | |
48bf5def RN |
1202 | { |
1203 | struct arc *a; | |
1204 | struct arc *aa; | |
1205 | ||
1206 | if (nfa->pre->outs == NULL) | |
1207 | return REG_UIMPOSSIBLE; | |
1208 | for (a = nfa->pre->outs; a != NULL; a = a->outchain) | |
1209 | for (aa = a->to->outs; aa != NULL; aa = aa->outchain) | |
1210 | if (aa->to == nfa->post) | |
1211 | return REG_UEMPTYMATCH; | |
1212 | return 0; | |
1213 | } | |
1214 | ||
1215 | /* | |
3ca4086b VS |
1216 | - compact - compact an NFA |
1217 | ^ static VOID compact(struct nfa *, struct cnfa *); | |
48bf5def | 1218 | */ |
3ca4086b VS |
1219 | static VOID |
1220 | compact(nfa, cnfa) | |
1221 | struct nfa *nfa; | |
1222 | struct cnfa *cnfa; | |
48bf5def RN |
1223 | { |
1224 | struct state *s; | |
1225 | struct arc *a; | |
3ca4086b VS |
1226 | size_t nstates; |
1227 | size_t narcs; | |
48bf5def RN |
1228 | struct carc *ca; |
1229 | struct carc *first; | |
1230 | ||
3ca4086b | 1231 | assert (!NISERR()); |
48bf5def RN |
1232 | |
1233 | nstates = 0; | |
1234 | narcs = 0; | |
3ca4086b | 1235 | for (s = nfa->states; s != NULL; s = s->next) { |
48bf5def RN |
1236 | nstates++; |
1237 | narcs += 1 + s->nouts + 1; | |
1238 | /* 1 as a fake for flags, nouts for arcs, 1 as endmarker */ | |
1239 | } | |
1240 | ||
3ca4086b VS |
1241 | cnfa->states = (struct carc **)MALLOC(nstates * sizeof(struct carc *)); |
1242 | cnfa->arcs = (struct carc *)MALLOC(narcs * sizeof(struct carc)); | |
1243 | if (cnfa->states == NULL || cnfa->arcs == NULL) { | |
48bf5def RN |
1244 | if (cnfa->states != NULL) |
1245 | FREE(cnfa->states); | |
1246 | if (cnfa->arcs != NULL) | |
1247 | FREE(cnfa->arcs); | |
1248 | NERR(REG_ESPACE); | |
1249 | return; | |
1250 | } | |
1251 | cnfa->nstates = nstates; | |
1252 | cnfa->pre = nfa->pre->no; | |
1253 | cnfa->post = nfa->post->no; | |
1254 | cnfa->bos[0] = nfa->bos[0]; | |
1255 | cnfa->bos[1] = nfa->bos[1]; | |
1256 | cnfa->eos[0] = nfa->eos[0]; | |
1257 | cnfa->eos[1] = nfa->eos[1]; | |
1258 | cnfa->ncolors = maxcolor(nfa->cm) + 1; | |
1259 | cnfa->flags = 0; | |
1260 | ||
1261 | ca = cnfa->arcs; | |
3ca4086b VS |
1262 | for (s = nfa->states; s != NULL; s = s->next) { |
1263 | assert((size_t)s->no < nstates); | |
48bf5def | 1264 | cnfa->states[s->no] = ca; |
3ca4086b | 1265 | ca->co = 0; /* clear and skip flags "arc" */ |
48bf5def RN |
1266 | ca++; |
1267 | first = ca; | |
1268 | for (a = s->outs; a != NULL; a = a->outchain) | |
3ca4086b VS |
1269 | switch (a->type) { |
1270 | case PLAIN: | |
1271 | ca->co = a->co; | |
1272 | ca->to = a->to->no; | |
1273 | ca++; | |
1274 | break; | |
1275 | case LACON: | |
1276 | assert(s->no != cnfa->pre); | |
1277 | ca->co = (color)(cnfa->ncolors + a->co); | |
1278 | ca->to = a->to->no; | |
1279 | ca++; | |
1280 | cnfa->flags |= HASLACONS; | |
1281 | break; | |
1282 | default: | |
1283 | assert(NOTREACHED); | |
1284 | break; | |
48bf5def | 1285 | } |
3ca4086b | 1286 | carcsort(first, ca-1); |
48bf5def RN |
1287 | ca->co = COLORLESS; |
1288 | ca->to = 0; | |
1289 | ca++; | |
1290 | } | |
1291 | assert(ca == &cnfa->arcs[narcs]); | |
1292 | assert(cnfa->nstates != 0); | |
1293 | ||
1294 | /* mark no-progress states */ | |
1295 | for (a = nfa->pre->outs; a != NULL; a = a->outchain) | |
1296 | cnfa->states[a->to->no]->co = 1; | |
1297 | cnfa->states[nfa->pre->no]->co = 1; | |
1298 | } | |
1299 | ||
1300 | /* | |
3ca4086b | 1301 | - carcsort - sort compacted-NFA arcs by color |
48bf5def RN |
1302 | * Really dumb algorithm, but if the list is long enough for that to matter, |
1303 | * you're in real trouble anyway. | |
3ca4086b | 1304 | ^ static VOID carcsort(struct carc *, struct carc *); |
48bf5def | 1305 | */ |
3ca4086b VS |
1306 | static VOID |
1307 | carcsort(first, last) | |
1308 | struct carc *first; | |
1309 | struct carc *last; | |
48bf5def RN |
1310 | { |
1311 | struct carc *p; | |
1312 | struct carc *q; | |
1313 | struct carc tmp; | |
1314 | ||
1315 | if (last - first <= 1) | |
1316 | return; | |
1317 | ||
1318 | for (p = first; p <= last; p++) | |
1319 | for (q = p; q <= last; q++) | |
1320 | if (p->co > q->co || | |
3ca4086b | 1321 | (p->co == q->co && p->to > q->to)) { |
48bf5def RN |
1322 | assert(p != q); |
1323 | tmp = *p; | |
1324 | *p = *q; | |
1325 | *q = tmp; | |
1326 | } | |
1327 | } | |
1328 | ||
1329 | /* | |
3ca4086b VS |
1330 | - freecnfa - free a compacted NFA |
1331 | ^ static VOID freecnfa(struct cnfa *); | |
48bf5def | 1332 | */ |
3ca4086b VS |
1333 | static VOID |
1334 | freecnfa(cnfa) | |
1335 | struct cnfa *cnfa; | |
48bf5def | 1336 | { |
3ca4086b | 1337 | assert(cnfa->nstates != 0); /* not empty already */ |
48bf5def RN |
1338 | cnfa->nstates = 0; |
1339 | FREE(cnfa->states); | |
1340 | FREE(cnfa->arcs); | |
1341 | } | |
1342 | ||
1343 | /* | |
3ca4086b VS |
1344 | - dumpnfa - dump an NFA in human-readable form |
1345 | ^ static VOID dumpnfa(struct nfa *, FILE *); | |
48bf5def | 1346 | */ |
3ca4086b VS |
1347 | static VOID |
1348 | dumpnfa(nfa, f) | |
1349 | struct nfa *nfa; | |
1350 | FILE *f; | |
48bf5def RN |
1351 | { |
1352 | #ifdef REG_DEBUG | |
1353 | struct state *s; | |
1354 | ||
1355 | fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no); | |
1356 | if (nfa->bos[0] != COLORLESS) | |
3ca4086b | 1357 | fprintf(f, ", bos [%ld]", (long)nfa->bos[0]); |
48bf5def | 1358 | if (nfa->bos[1] != COLORLESS) |
3ca4086b | 1359 | fprintf(f, ", bol [%ld]", (long)nfa->bos[1]); |
48bf5def | 1360 | if (nfa->eos[0] != COLORLESS) |
3ca4086b | 1361 | fprintf(f, ", eos [%ld]", (long)nfa->eos[0]); |
48bf5def | 1362 | if (nfa->eos[1] != COLORLESS) |
3ca4086b | 1363 | fprintf(f, ", eol [%ld]", (long)nfa->eos[1]); |
48bf5def RN |
1364 | fprintf(f, "\n"); |
1365 | for (s = nfa->states; s != NULL; s = s->next) | |
1366 | dumpstate(s, f); | |
1367 | if (nfa->parent == NULL) | |
1368 | dumpcolors(nfa->cm, f); | |
1369 | fflush(f); | |
1370 | #endif | |
1371 | } | |
1372 | ||
3ca4086b VS |
1373 | #ifdef REG_DEBUG /* subordinates of dumpnfa */ |
1374 | /* | |
1375 | ^ #ifdef REG_DEBUG | |
1376 | */ | |
48bf5def RN |
1377 | |
1378 | /* | |
3ca4086b VS |
1379 | - dumpstate - dump an NFA state in human-readable form |
1380 | ^ static VOID dumpstate(struct state *, FILE *); | |
48bf5def | 1381 | */ |
3ca4086b VS |
1382 | static VOID |
1383 | dumpstate(s, f) | |
1384 | struct state *s; | |
1385 | FILE *f; | |
48bf5def RN |
1386 | { |
1387 | struct arc *a; | |
1388 | ||
1389 | fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "", | |
3ca4086b | 1390 | (s->flag) ? s->flag : '.'); |
48bf5def RN |
1391 | if (s->prev != NULL && s->prev->next != s) |
1392 | fprintf(f, "\tstate chain bad\n"); | |
1393 | if (s->nouts == 0) | |
1394 | fprintf(f, "\tno out arcs\n"); | |
1395 | else | |
1396 | dumparcs(s, f); | |
1397 | fflush(f); | |
3ca4086b | 1398 | for (a = s->ins; a != NULL; a = a->inchain) { |
48bf5def RN |
1399 | if (a->to != s) |
1400 | fprintf(f, "\tlink from %d to %d on %d's in-chain\n", | |
1401 | a->from->no, a->to->no, s->no); | |
1402 | } | |
1403 | } | |
1404 | ||
1405 | /* | |
3ca4086b VS |
1406 | - dumparcs - dump out-arcs in human-readable form |
1407 | ^ static VOID dumparcs(struct state *, FILE *); | |
48bf5def | 1408 | */ |
3ca4086b VS |
1409 | static VOID |
1410 | dumparcs(s, f) | |
1411 | struct state *s; | |
1412 | FILE *f; | |
48bf5def | 1413 | { |
3ca4086b | 1414 | int pos; |
48bf5def RN |
1415 | |
1416 | assert(s->nouts > 0); | |
1417 | /* printing arcs in reverse order is usually clearer */ | |
1418 | pos = dumprarcs(s->outs, s, f, 1); | |
1419 | if (pos != 1) | |
1420 | fprintf(f, "\n"); | |
1421 | } | |
1422 | ||
1423 | /* | |
3ca4086b VS |
1424 | - dumprarcs - dump remaining outarcs, recursively, in reverse order |
1425 | ^ static int dumprarcs(struct arc *, struct state *, FILE *, int); | |
48bf5def | 1426 | */ |
3ca4086b VS |
1427 | static int /* resulting print position */ |
1428 | dumprarcs(a, s, f, pos) | |
1429 | struct arc *a; | |
1430 | struct state *s; | |
1431 | FILE *f; | |
1432 | int pos; /* initial print position */ | |
48bf5def RN |
1433 | { |
1434 | if (a->outchain != NULL) | |
1435 | pos = dumprarcs(a->outchain, s, f, pos); | |
1436 | dumparc(a, s, f); | |
3ca4086b | 1437 | if (pos == 5) { |
48bf5def RN |
1438 | fprintf(f, "\n"); |
1439 | pos = 1; | |
3ca4086b | 1440 | } else |
48bf5def RN |
1441 | pos++; |
1442 | return pos; | |
1443 | } | |
1444 | ||
1445 | /* | |
3ca4086b VS |
1446 | - dumparc - dump one outarc in readable form, including prefixing tab |
1447 | ^ static VOID dumparc(struct arc *, struct state *, FILE *); | |
48bf5def | 1448 | */ |
3ca4086b VS |
1449 | static VOID |
1450 | dumparc(a, s, f) | |
1451 | struct arc *a; | |
1452 | struct state *s; | |
1453 | FILE *f; | |
48bf5def RN |
1454 | { |
1455 | struct arc *aa; | |
1456 | struct arcbatch *ab; | |
1457 | ||
1458 | fprintf(f, "\t"); | |
3ca4086b VS |
1459 | switch (a->type) { |
1460 | case PLAIN: | |
1461 | fprintf(f, "[%ld]", (long)a->co); | |
1462 | break; | |
1463 | case AHEAD: | |
1464 | fprintf(f, ">%ld>", (long)a->co); | |
1465 | break; | |
1466 | case BEHIND: | |
1467 | fprintf(f, "<%ld<", (long)a->co); | |
1468 | break; | |
1469 | case LACON: | |
1470 | fprintf(f, ":%ld:", (long)a->co); | |
1471 | break; | |
1472 | case '^': | |
1473 | case '$': | |
1474 | fprintf(f, "%c%d", a->type, (int)a->co); | |
1475 | break; | |
1476 | case EMPTY: | |
1477 | break; | |
1478 | default: | |
1479 | fprintf(f, "0x%x/0%lo", a->type, (long)a->co); | |
1480 | break; | |
48bf5def RN |
1481 | } |
1482 | if (a->from != s) | |
1483 | fprintf(f, "?%d?", a->from->no); | |
3ca4086b | 1484 | for (ab = &a->from->oas; ab != NULL; ab = ab->next) { |
48bf5def RN |
1485 | for (aa = &ab->a[0]; aa < &ab->a[ABSIZE]; aa++) |
1486 | if (aa == a) | |
3ca4086b | 1487 | break; /* NOTE BREAK OUT */ |
48bf5def | 1488 | if (aa < &ab->a[ABSIZE]) /* propagate break */ |
3ca4086b | 1489 | break; /* NOTE BREAK OUT */ |
48bf5def RN |
1490 | } |
1491 | if (ab == NULL) | |
3ca4086b | 1492 | fprintf(f, "?!?"); /* not in allocated space */ |
48bf5def | 1493 | fprintf(f, "->"); |
3ca4086b | 1494 | if (a->to == NULL) { |
48bf5def RN |
1495 | fprintf(f, "NULL"); |
1496 | return; | |
1497 | } | |
1498 | fprintf(f, "%d", a->to->no); | |
1499 | for (aa = a->to->ins; aa != NULL; aa = aa->inchain) | |
1500 | if (aa == a) | |
3ca4086b | 1501 | break; /* NOTE BREAK OUT */ |
48bf5def | 1502 | if (aa == NULL) |
3ca4086b | 1503 | fprintf(f, "?!?"); /* missing from in-chain */ |
48bf5def | 1504 | } |
48bf5def RN |
1505 | |
1506 | /* | |
3ca4086b | 1507 | ^ #endif |
48bf5def | 1508 | */ |
3ca4086b VS |
1509 | #endif /* ifdef REG_DEBUG */ |
1510 | ||
1511 | /* | |
1512 | - dumpcnfa - dump a compacted NFA in human-readable form | |
1513 | ^ static VOID dumpcnfa(struct cnfa *, FILE *); | |
1514 | */ | |
1515 | static VOID | |
1516 | dumpcnfa(cnfa, f) | |
1517 | struct cnfa *cnfa; | |
1518 | FILE *f; | |
48bf5def | 1519 | { |
3ca4086b VS |
1520 | #ifdef REG_DEBUG |
1521 | int st; | |
48bf5def RN |
1522 | |
1523 | fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post); | |
1524 | if (cnfa->bos[0] != COLORLESS) | |
3ca4086b | 1525 | fprintf(f, ", bos [%ld]", (long)cnfa->bos[0]); |
48bf5def | 1526 | if (cnfa->bos[1] != COLORLESS) |
3ca4086b | 1527 | fprintf(f, ", bol [%ld]", (long)cnfa->bos[1]); |
48bf5def | 1528 | if (cnfa->eos[0] != COLORLESS) |
3ca4086b | 1529 | fprintf(f, ", eos [%ld]", (long)cnfa->eos[0]); |
48bf5def | 1530 | if (cnfa->eos[1] != COLORLESS) |
3ca4086b VS |
1531 | fprintf(f, ", eol [%ld]", (long)cnfa->eos[1]); |
1532 | if (cnfa->flags&HASLACONS) | |
48bf5def RN |
1533 | fprintf(f, ", haslacons"); |
1534 | fprintf(f, "\n"); | |
1535 | for (st = 0; st < cnfa->nstates; st++) | |
1536 | dumpcstate(st, cnfa->states[st], cnfa, f); | |
1537 | fflush(f); | |
48bf5def | 1538 | #endif |
3ca4086b | 1539 | } |
48bf5def | 1540 | |
3ca4086b VS |
1541 | #ifdef REG_DEBUG /* subordinates of dumpcnfa */ |
1542 | /* | |
1543 | ^ #ifdef REG_DEBUG | |
1544 | */ | |
48bf5def RN |
1545 | |
1546 | /* | |
3ca4086b VS |
1547 | - dumpcstate - dump a compacted-NFA state in human-readable form |
1548 | ^ static VOID dumpcstate(int, struct carc *, struct cnfa *, FILE *); | |
48bf5def | 1549 | */ |
3ca4086b VS |
1550 | static VOID |
1551 | dumpcstate(st, ca, cnfa, f) | |
1552 | int st; | |
1553 | struct carc *ca; | |
1554 | struct cnfa *cnfa; | |
1555 | FILE *f; | |
48bf5def | 1556 | { |
3ca4086b VS |
1557 | int i; |
1558 | int pos; | |
48bf5def RN |
1559 | |
1560 | fprintf(f, "%d%s", st, (ca[0].co) ? ":" : "."); | |
1561 | pos = 1; | |
3ca4086b | 1562 | for (i = 1; ca[i].co != COLORLESS; i++) { |
48bf5def | 1563 | if (ca[i].co < cnfa->ncolors) |
3ca4086b | 1564 | fprintf(f, "\t[%ld]->%d", (long)ca[i].co, ca[i].to); |
48bf5def | 1565 | else |
3ca4086b VS |
1566 | fprintf(f, "\t:%ld:->%d", (long)ca[i].co-cnfa->ncolors, |
1567 | ca[i].to); | |
1568 | if (pos == 5) { | |
48bf5def RN |
1569 | fprintf(f, "\n"); |
1570 | pos = 1; | |
3ca4086b | 1571 | } else |
48bf5def RN |
1572 | pos++; |
1573 | } | |
1574 | if (i == 1 || pos != 1) | |
1575 | fprintf(f, "\n"); | |
1576 | fflush(f); | |
1577 | } | |
1578 | ||
3ca4086b VS |
1579 | /* |
1580 | ^ #endif | |
1581 | */ | |
1582 | #endif /* ifdef REG_DEBUG */ |