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Cygwin: strptime: add release note
[newlib-cygwin.git] / winsup / cygwin / regex / engine.c
blob5e12ab7f3735dea761bbe7c4832d9327b325bde8
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
5 * Copyright (c) 1992, 1993, 1994
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Henry Spencer.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)engine.c 8.5 (Berkeley) 3/20/94
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <stdbool.h>
42
43 /*
44 * The matching engine and friends. This file is #included by regexec.c
45 * after suitable #defines of a variety of macros used herein, so that
46 * different state representations can be used without duplicating masses
47 * of code.
48 */
49
50 #ifdef SNAMES
51 #define stepback sstepback
52 #define matcher smatcher
53 #define walk swalk
54 #define dissect sdissect
55 #define backref sbackref
56 #define step sstep
57 #define print sprint
58 #define at sat
59 #define match smat
60 #endif
61 #ifdef LNAMES
62 #define stepback lstepback
63 #define matcher lmatcher
64 #define walk lwalk
65 #define dissect ldissect
66 #define backref lbackref
67 #define step lstep
68 #define print lprint
69 #define at lat
70 #define match lmat
71 #endif
72 #ifdef MNAMES
73 #define stepback mstepback
74 #define matcher mmatcher
75 #define walk mwalk
76 #define dissect mdissect
77 #define backref mbackref
78 #define step mstep
79 #define print mprint
80 #define at mat
81 #define match mmat
82 #endif
83
84 /* another structure passed up and down to avoid zillions of parameters */
85 struct match {
86 struct re_guts *g;
87 int eflags;
88 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
89 const char *offp; /* offsets work from here */
90 const char *beginp; /* start of string -- virtual NUL precedes */
91 const char *endp; /* end of string -- virtual NUL here */
92 const char *coldp; /* can be no match starting before here */
93 const char **lastpos; /* [nplus+1] */
94 STATEVARS;
95 states st; /* current states */
96 states fresh; /* states for a fresh start */
97 states tmp; /* temporary */
98 states empty; /* empty set of states */
99 mbstate_t mbs; /* multibyte conversion state */
100 };
101
102 /* ========= begin header generated by ./mkh ========= */
103 #ifdef __cplusplus
104 extern "C" {
105 #endif
106
107 /* === engine.c === */
108 static int matcher(struct re_guts *g, const char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
109 static const char *dissect(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst);
110 static const char *backref(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, sopno lev, int);
111 static const char *walk(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, bool fast);
112 static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_t ch, states aft, int sflags);
113 #define MAX_RECURSION 100
114 #define BOL (OUT-1)
115 #define EOL (BOL-1)
116 #define BOLEOL (BOL-2)
117 #define NOTHING (BOL-3)
118 #define BOW (BOL-4)
119 #define EOW (BOL-5)
120 #define BADCHAR (BOL-6)
121 #define NWBND (BOL-7)
122 #define NONCHAR(c) ((int)(c) <= OUT)
123 /* sflags */
124 #define SBOS 0x0001
125 #define SEOS 0x0002
126
127 #ifdef REDEBUG
128 static void print(struct match *m, const char *caption, states st, int ch, FILE *d);
129 #endif
130 #ifdef REDEBUG
131 static void at(struct match *m, const char *title, const char *start, const char *stop, sopno startst, sopno stopst);
132 #endif
133 #ifdef REDEBUG
134 static const char *pchar(int ch);
135 #endif
136
137 #ifdef __cplusplus
138 }
139 #endif
140 /* ========= end header generated by ./mkh ========= */
141
142 #ifdef REDEBUG
143 #define SP(t, s, c) print(m, t, s, c, stdout)
144 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
145 #define NOTE(str) { if (m->eflags&REG_TRACE) printf("=%s\n", (str)); }
146 #else
147 #define SP(t, s, c) /* nothing */
148 #define AT(t, p1, p2, s1, s2) /* nothing */
149 #define NOTE(s) /* nothing */
150 #endif
151
152 /*
153 * Given a multibyte string pointed to by start, step back nchar characters
154 * from current position pointed to by cur.
155 */
156 static const char *
157 stepback(const char *start, const char *cur, int nchar)
158 {
159 const char *ret;
160 int wc, mbc;
161 mbstate_t mbs;
162 size_t clen;
163
164 if (MB_CUR_MAX == 1)
165 return ((cur - nchar) > start ? cur - nchar : NULL);
166
167 ret = cur;
168 for (wc = nchar; wc > 0; wc--) {
169 for (mbc = 1; mbc <= MB_CUR_MAX; mbc++) {
170 if ((ret - mbc) < start)
171 return (NULL);
172 memset(&mbs, 0, sizeof(mbs));
173 clen = mbrtowi(NULL, ret - mbc, mbc, &mbs);
174 if (clen != (size_t)-1 && clen != (size_t)-2)
175 break;
176 }
177 if (mbc > MB_CUR_MAX)
178 return (NULL);
179 ret -= mbc;
180 }
181
182 return (ret);
183 }
184
185 /*
186 - matcher - the actual matching engine
187 == static int matcher(struct re_guts *g, const char *string, \
188 == size_t nmatch, regmatch_t pmatch[], int eflags);
189 */
190 static int /* 0 success, REG_NOMATCH failure */
191 matcher(struct re_guts *g,
192 const char *string,
193 size_t nmatch,
194 regmatch_t pmatch[],
195 int eflags)
196 {
197 const char *endp;
198 size_t i;
199 struct match mv;
200 struct match *m = &mv;
201 const char *dp = NULL;
202 const sopno gf = g->firststate+1; /* +1 for OEND */
203 const sopno gl = g->laststate;
204 const char *start;
205 const char *stop;
206 /* Boyer-Moore algorithms variables */
207 const char *pp;
208 int cj, mj;
209 const char *mustfirst;
210 const char *mustlast;
211 int *matchjump;
212 int *charjump;
213
214 /* simplify the situation where possible */
215 if (g->cflags&REG_NOSUB)
216 nmatch = 0;
217 if (eflags&REG_STARTEND) {
218 start = string + pmatch[0].rm_so;
219 stop = string + pmatch[0].rm_eo;
220 } else {
221 start = string;
222 stop = start + strlen(start);
223 }
224 if (stop < start)
225 return(REG_INVARG);
226
227 /* prescreening; this does wonders for this rather slow code */
228 if (g->must != NULL) {
229 if (g->charjump != NULL && g->matchjump != NULL) {
230 mustfirst = g->must;
231 mustlast = g->must + g->mlen - 1;
232 charjump = g->charjump;
233 matchjump = g->matchjump;
234 pp = mustlast;
235 for (dp = start+g->mlen-1; dp < stop;) {
236 /* Fast skip non-matches */
237 while (dp < stop && charjump[(int)*dp])
238 dp += charjump[(int)*dp];
239
240 if (dp >= stop)
241 break;
242
243 /* Greedy matcher */
244 /* We depend on not being used for
245 * for strings of length 1
246 */
247 while (*--dp == *--pp && pp != mustfirst);
248
249 if (*dp == *pp)
250 break;
251
252 /* Jump to next possible match */
253 mj = matchjump[pp - mustfirst];
254 cj = charjump[(int)*dp];
255 dp += (cj < mj ? mj : cj);
256 pp = mustlast;
257 }
258 if (pp != mustfirst)
259 return(REG_NOMATCH);
260 } else {
261 for (dp = start; dp < stop; dp++)
262 if (*dp == g->must[0] &&
263 stop - dp >= g->mlen &&
264 memcmp(dp, g->must, (size_t)g->mlen) == 0)
265 break;
266 if (dp == stop) /* we didn't find g->must */
267 return(REG_NOMATCH);
268 }
269 }
270
271 /* match struct setup */
272 m->g = g;
273 m->eflags = eflags;
274 m->pmatch = NULL;
275 m->lastpos = NULL;
276 m->offp = string;
277 m->beginp = start;
278 m->endp = stop;
279 STATESETUP(m, 4);
280 SETUP(m->st);
281 SETUP(m->fresh);
282 SETUP(m->tmp);
283 SETUP(m->empty);
284 CLEAR(m->empty);
285 ZAPSTATE(&m->mbs);
286
287 /* Adjust start according to moffset, to speed things up */
288 if (dp != NULL && g->moffset > -1) {
289 const char *nstart;
290
291 nstart = stepback(start, dp, g->moffset);
292 if (nstart != NULL)
293 start = nstart;
294 }
295
296 SP("mloop", m->st, *start);
297
298 /* this loop does only one repetition except for backrefs */
299 for (;;) {
300 endp = walk(m, start, stop, gf, gl, true);
301 if (endp == NULL) { /* a miss */
302 if (m->pmatch != NULL)
303 free((char *)m->pmatch);
304 if (m->lastpos != NULL)
305 free((char *)m->lastpos);
306 STATETEARDOWN(m);
307 return(REG_NOMATCH);
308 }
309 if (nmatch == 0 && !g->backrefs)
310 break; /* no further info needed */
311
312 /* where? */
313 assert(m->coldp != NULL);
314 for (;;) {
315 NOTE("finding start");
316 endp = walk(m, m->coldp, stop, gf, gl, false);
317 if (endp != NULL)
318 break;
319 assert(m->coldp < m->endp);
320 m->coldp += XMBRTOWC(NULL, m->coldp,
321 m->endp - m->coldp, &m->mbs, 0);
322 }
323 if (nmatch == 1 && !g->backrefs)
324 break; /* no further info needed */
325
326 /* oh my, he wants the subexpressions... */
327 if (m->pmatch == NULL)
328 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
329 sizeof(regmatch_t));
330 if (m->pmatch == NULL) {
331 STATETEARDOWN(m);
332 return(REG_ESPACE);
333 }
334 for (i = 1; i <= m->g->nsub; i++)
335 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
336 if (!g->backrefs && !(m->eflags&REG_BACKR)) {
337 NOTE("dissecting");
338 dp = dissect(m, m->coldp, endp, gf, gl);
339 } else {
340 if (g->nplus > 0 && m->lastpos == NULL)
341 m->lastpos = malloc((g->nplus+1) *
342 sizeof(const char *));
343 if (g->nplus > 0 && m->lastpos == NULL) {
344 free(m->pmatch);
345 STATETEARDOWN(m);
346 return(REG_ESPACE);
347 }
348 NOTE("backref dissect");
349 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
350 }
351 if (dp != NULL)
352 break;
353
354 /* uh-oh... we couldn't find a subexpression-level match */
355 assert(g->backrefs); /* must be back references doing it */
356 assert(g->nplus == 0 || m->lastpos != NULL);
357 for (;;) {
358 if (dp != NULL || endp <= m->coldp)
359 break; /* defeat */
360 NOTE("backoff");
361 endp = walk(m, m->coldp, endp-1, gf, gl, false);
362 if (endp == NULL)
363 break; /* defeat */
364 /* try it on a shorter possibility */
365 #ifndef NDEBUG
366 for (i = 1; i <= m->g->nsub; i++) {
367 assert(m->pmatch[i].rm_so == -1);
368 assert(m->pmatch[i].rm_eo == -1);
369 }
370 #endif
371 NOTE("backoff dissect");
372 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
373 }
374 assert(dp == NULL || dp == endp);
375 if (dp != NULL) /* found a shorter one */
376 break;
377
378 /* despite initial appearances, there is no match here */
379 NOTE("false alarm");
380 /* recycle starting later */
381 start = m->coldp + XMBRTOWC(NULL, m->coldp,
382 stop - m->coldp, &m->mbs, 0);
383 assert(start <= stop);
384 }
385
386 /* fill in the details if requested */
387 if (nmatch > 0) {
388 pmatch[0].rm_so = m->coldp - m->offp;
389 pmatch[0].rm_eo = endp - m->offp;
390 }
391 if (nmatch > 1) {
392 assert(m->pmatch != NULL);
393 for (i = 1; i < nmatch; i++)
394 if (i <= m->g->nsub)
395 pmatch[i] = m->pmatch[i];
396 else {
397 pmatch[i].rm_so = -1;
398 pmatch[i].rm_eo = -1;
399 }
400 }
401
402 if (m->pmatch != NULL)
403 free((char *)m->pmatch);
404 if (m->lastpos != NULL)
405 free((char *)m->lastpos);
406 STATETEARDOWN(m);
407 return(0);
408 }
409
410 /*
411 - dissect - figure out what matched what, no back references
412 == static const char *dissect(struct match *m, const char *start, \
413 == const char *stop, sopno startst, sopno stopst);
414 */
415 static const char * /* == stop (success) always */
416 dissect(struct match *m,
417 const char *start,
418 const char *stop,
419 sopno startst,
420 sopno stopst)
421 {
422 int i;
423 sopno ss; /* start sop of current subRE */
424 sopno es; /* end sop of current subRE */
425 const char *sp; /* start of string matched by it */
426 const char *stp; /* string matched by it cannot pass here */
427 const char *rest; /* start of rest of string */
428 const char *tail; /* string unmatched by rest of RE */
429 sopno ssub; /* start sop of subsubRE */
430 sopno esub; /* end sop of subsubRE */
431 const char *ssp; /* start of string matched by subsubRE */
432 const char *sep; /* end of string matched by subsubRE */
433 const char *oldssp; /* previous ssp */
434 const char *dp __unused;
435
436 AT("diss", start, stop, startst, stopst);
437 sp = start;
438 for (ss = startst; ss < stopst; ss = es) {
439 /* identify end of subRE */
440 es = ss;
441 switch (OP(m->g->strip[es])) {
442 case OPLUS_:
443 case OQUEST_:
444 es += OPND(m->g->strip[es]);
445 break;
446 case OCH_:
447 while (OP(m->g->strip[es]) != (sop)O_CH)
448 es += OPND(m->g->strip[es]);
449 break;
450 }
451 es++;
452
453 /* figure out what it matched */
454 switch (OP(m->g->strip[ss])) {
455 case OEND:
456 assert(nope);
457 break;
458 case OCHAR:
459 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
460 break;
461 case OBOL:
462 case OEOL:
463 case OBOW:
464 case OEOW:
465 case OBOS:
466 case OEOS:
467 case OWBND:
468 case ONWBND:
469 break;
470 case OANY:
471 case OANYOF:
472 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
473 break;
474 case OBACK_:
475 case O_BACK:
476 assert(nope);
477 break;
478 /* cases where length of match is hard to find */
479 case OQUEST_:
480 stp = stop;
481 for (;;) {
482 /* how long could this one be? */
483 rest = walk(m, sp, stp, ss, es, false);
484 assert(rest != NULL); /* it did match */
485 /* could the rest match the rest? */
486 tail = walk(m, rest, stop, es, stopst, false);
487 if (tail == stop)
488 break; /* yes! */
489 /* no -- try a shorter match for this one */
490 stp = rest - 1;
491 assert(stp >= sp); /* it did work */
492 }
493 ssub = ss + 1;
494 esub = es - 1;
495 /* did innards match? */
496 if (walk(m, sp, rest, ssub, esub, false) != NULL) {
497 dp = dissect(m, sp, rest, ssub, esub);
498 assert(dp == rest);
499 } else /* no */
500 assert(sp == rest);
501 sp = rest;
502 break;
503 case OPLUS_:
504 stp = stop;
505 for (;;) {
506 /* how long could this one be? */
507 rest = walk(m, sp, stp, ss, es, false);
508 assert(rest != NULL); /* it did match */
509 /* could the rest match the rest? */
510 tail = walk(m, rest, stop, es, stopst, false);
511 if (tail == stop)
512 break; /* yes! */
513 /* no -- try a shorter match for this one */
514 stp = rest - 1;
515 assert(stp >= sp); /* it did work */
516 }
517 ssub = ss + 1;
518 esub = es - 1;
519 ssp = sp;
520 oldssp = ssp;
521 for (;;) { /* find last match of innards */
522 sep = walk(m, ssp, rest, ssub, esub, false);
523 if (sep == NULL || sep == ssp)
524 break; /* failed or matched null */
525 oldssp = ssp; /* on to next try */
526 ssp = sep;
527 }
528 if (sep == NULL) {
529 /* last successful match */
530 sep = ssp;
531 ssp = oldssp;
532 }
533 assert(sep == rest); /* must exhaust substring */
534 assert(walk(m, ssp, sep, ssub, esub, false) == rest);
535 dp = dissect(m, ssp, sep, ssub, esub);
536 assert(dp == sep);
537 sp = rest;
538 break;
539 case OCH_:
540 stp = stop;
541 for (;;) {
542 /* how long could this one be? */
543 rest = walk(m, sp, stp, ss, es, false);
544 assert(rest != NULL); /* it did match */
545 /* could the rest match the rest? */
546 tail = walk(m, rest, stop, es, stopst, false);
547 if (tail == stop)
548 break; /* yes! */
549 /* no -- try a shorter match for this one */
550 stp = rest - 1;
551 assert(stp >= sp); /* it did work */
552 }
553 ssub = ss + 1;
554 esub = ss + OPND(m->g->strip[ss]) - 1;
555 assert(OP(m->g->strip[esub]) == OOR1);
556 for (;;) { /* find first matching branch */
557 if (walk(m, sp, rest, ssub, esub, false) == rest)
558 break; /* it matched all of it */
559 /* that one missed, try next one */
560 assert(OP(m->g->strip[esub]) == OOR1);
561 esub++;
562 assert(OP(m->g->strip[esub]) == OOR2);
563 ssub = esub + 1;
564 esub += OPND(m->g->strip[esub]);
565 if (OP(m->g->strip[esub]) == (sop)OOR2)
566 esub--;
567 else
568 assert(OP(m->g->strip[esub]) == O_CH);
569 }
570 dp = dissect(m, sp, rest, ssub, esub);
571 assert(dp == rest);
572 sp = rest;
573 break;
574 case O_PLUS:
575 case O_QUEST:
576 case OOR1:
577 case OOR2:
578 case O_CH:
579 assert(nope);
580 break;
581 case OLPAREN:
582 i = OPND(m->g->strip[ss]);
583 assert(0 < i && i <= m->g->nsub);
584 m->pmatch[i].rm_so = sp - m->offp;
585 break;
586 case ORPAREN:
587 i = OPND(m->g->strip[ss]);
588 assert(0 < i && i <= m->g->nsub);
589 m->pmatch[i].rm_eo = sp - m->offp;
590 break;
591 default: /* uh oh */
592 assert(nope);
593 break;
594 }
595 }
596
597 assert(sp == stop);
598 return(sp);
599 }
600
601 #define ISBOW(m, sp) \
602 (sp < m->endp && ISWORD(*sp) && \
603 ((sp == m->beginp && !(m->eflags&REG_NOTBOL)) || \
604 (sp > m->offp && !ISWORD(*(sp-1)))))
605 #define ISEOW(m, sp) \
606 (((sp == m->endp && !(m->eflags&REG_NOTEOL)) || \
607 (sp < m->endp && *sp == '\n' && \
608 (m->g->cflags&REG_NEWLINE)) || \
609 (sp < m->endp && !ISWORD(*sp)) ) && \
610 (sp > m->beginp && ISWORD(*(sp-1)))) \
611
612 /*
613 - backref - figure out what matched what, figuring in back references
614 == static const char *backref(struct match *m, const char *start, \
615 == const char *stop, sopno startst, sopno stopst, sopno lev);
616 */
617 static const char * /* == stop (success) or NULL (failure) */
618 backref(struct match *m,
619 const char *start,
620 const char *stop,
621 sopno startst,
622 sopno stopst,
623 sopno lev, /* PLUS nesting level */
624 int rec)
625 {
626 int i;
627 sopno ss; /* start sop of current subRE */
628 const char *sp; /* start of string matched by it */
629 sopno ssub; /* start sop of subsubRE */
630 sopno esub; /* end sop of subsubRE */
631 const char *ssp; /* start of string matched by subsubRE */
632 const char *dp;
633 size_t len;
634 int hard;
635 sop s;
636 regoff_t offsave;
637 cset *cs;
638 wint_t wc;
639
640 AT("back", start, stop, startst, stopst);
641 sp = start;
642
643 /* get as far as we can with easy stuff */
644 hard = 0;
645 for (ss = startst; !hard && ss < stopst; ss++)
646 switch (OP(s = m->g->strip[ss])) {
647 case OCHAR:
648 if (sp == stop)
649 return(NULL);
650 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
651 if (wc != OPND(s))
652 return(NULL);
653 break;
654 case OANY:
655 if (sp == stop)
656 return(NULL);
657 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
658 if (wc == BADCHAR)
659 return (NULL);
660 break;
661 case OANYOF:
662 if (sp == stop)
663 return (NULL);
664 cs = &m->g->sets[OPND(s)];
665 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
666 if (wc == BADCHAR || !CHIN(cs, wc))
667 return(NULL);
668 break;
669 case OBOS:
670 if (sp == m->beginp && (m->eflags & REG_NOTBOL) == 0)
671 { /* yes */ }
672 else
673 return(NULL);
674 break;
675 case OEOS:
676 if (sp == m->endp && (m->eflags & REG_NOTEOL) == 0)
677 { /* yes */ }
678 else
679 return(NULL);
680 break;
681 case OBOL:
682 if ((sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
683 (sp > m->offp && sp < m->endp &&
684 *(sp-1) == '\n' && (m->g->cflags&REG_NEWLINE)))
685 { /* yes */ }
686 else
687 return(NULL);
688 break;
689 case OEOL:
690 if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
691 (sp < m->endp && *sp == '\n' &&
692 (m->g->cflags&REG_NEWLINE)) )
693 { /* yes */ }
694 else
695 return(NULL);
696 break;
697 case OWBND:
698 if (ISBOW(m, sp) || ISEOW(m, sp))
699 { /* yes */ }
700 else
701 return(NULL);
702 break;
703 case ONWBND:
704 if (((sp == m->beginp) && !ISWORD(*sp)) ||
705 (sp == m->endp && !ISWORD(*(sp - 1))))
706 { /* yes, beginning/end of subject */ }
707 else if (ISWORD(*(sp - 1)) == ISWORD(*sp))
708 { /* yes, beginning/end of subject */ }
709 else
710 return(NULL);
711 break;
712 case OBOW:
713 if (ISBOW(m, sp))
714 { /* yes */ }
715 else
716 return(NULL);
717 break;
718 case OEOW:
719 if (ISEOW(m, sp))
720 { /* yes */ }
721 else
722 return(NULL);
723 break;
724 case O_QUEST:
725 break;
726 case OOR1: /* matches null but needs to skip */
727 ss++;
728 s = m->g->strip[ss];
729 do {
730 assert(OP(s) == OOR2);
731 ss += OPND(s);
732 } while (OP(s = m->g->strip[ss]) != (sop)O_CH);
733 /* note that the ss++ gets us past the O_CH */
734 break;
735 default: /* have to make a choice */
736 hard = 1;
737 break;
738 }
739 if (!hard) { /* that was it! */
740 if (sp != stop)
741 return(NULL);
742 return(sp);
743 }
744 ss--; /* adjust for the for's final increment */
745
746 /* the hard stuff */
747 AT("hard", sp, stop, ss, stopst);
748 s = m->g->strip[ss];
749 switch (OP(s)) {
750 case OBACK_: /* the vilest depths */
751 i = OPND(s);
752 assert(0 < i && i <= m->g->nsub);
753 if (m->pmatch[i].rm_eo == -1)
754 return(NULL);
755 assert(m->pmatch[i].rm_so != -1);
756 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
757 if (len == 0 && rec++ > MAX_RECURSION)
758 return(NULL);
759 assert(stop - m->beginp >= len);
760 if (sp > stop - len)
761 return(NULL); /* not enough left to match */
762 ssp = m->offp + m->pmatch[i].rm_so;
763 if (memcmp(sp, ssp, len) != 0)
764 return(NULL);
765 while (m->g->strip[ss] != (sop)SOP(O_BACK, i))
766 ss++;
767 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
768 case OQUEST_: /* to null or not */
769 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
770 if (dp != NULL)
771 return(dp); /* not */
772 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
773 case OPLUS_:
774 assert(m->lastpos != NULL);
775 assert(lev+1 <= m->g->nplus);
776 m->lastpos[lev+1] = sp;
777 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
778 case O_PLUS:
779 if (sp == m->lastpos[lev]) /* last pass matched null */
780 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
781 /* try another pass */
782 m->lastpos[lev] = sp;
783 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
784 if (dp == NULL)
785 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
786 else
787 return(dp);
788 case OCH_: /* find the right one, if any */
789 ssub = ss + 1;
790 esub = ss + OPND(s) - 1;
791 assert(OP(m->g->strip[esub]) == OOR1);
792 for (;;) { /* find first matching branch */
793 dp = backref(m, sp, stop, ssub, esub, lev, rec);
794 if (dp != NULL)
795 return(dp);
796 /* that one missed, try next one */
797 if (OP(m->g->strip[esub]) == (sop)O_CH)
798 return(NULL); /* there is none */
799 esub++;
800 assert(OP(m->g->strip[esub]) == (sop)OOR2);
801 ssub = esub + 1;
802 esub += OPND(m->g->strip[esub]);
803 if (OP(m->g->strip[esub]) == (sop)OOR2)
804 esub--;
805 else
806 assert(OP(m->g->strip[esub]) == O_CH);
807 }
808 /* NOTREACHED */
809 break;
810 case OLPAREN: /* must undo assignment if rest fails */
811 i = OPND(s);
812 assert(0 < i && i <= m->g->nsub);
813 offsave = m->pmatch[i].rm_so;
814 m->pmatch[i].rm_so = sp - m->offp;
815 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
816 if (dp != NULL)
817 return(dp);
818 m->pmatch[i].rm_so = offsave;
819 return(NULL);
820 case ORPAREN: /* must undo assignment if rest fails */
821 i = OPND(s);
822 assert(0 < i && i <= m->g->nsub);
823 offsave = m->pmatch[i].rm_eo;
824 m->pmatch[i].rm_eo = sp - m->offp;
825 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
826 if (dp != NULL)
827 return(dp);
828 m->pmatch[i].rm_eo = offsave;
829 return(NULL);
830 default: /* uh oh */
831 assert(nope);
832 break;
833 }
834
835 /* "can't happen" */
836 assert(nope);
837 /* NOTREACHED */
838 return "shut up gcc";
839 }
840
841 /*
842 - walk - step through the string either quickly or slowly
843 == static const char *walk(struct match *m, const char *start, \
844 == const char *stop, sopno startst, sopno stopst, bool fast);
845 */
846 static const char * /* where it ended, or NULL */
847 walk(struct match *m, const char *start, const char *stop, sopno startst,
848 sopno stopst, bool fast)
849 {
850 states st = m->st;
851 states fresh = m->fresh;
852 states empty = m->empty;
853 states tmp = m->tmp;
854 const char *p = start;
855 wint_t c;
856 wint_t lastc; /* previous c */
857 wint_t flagch;
858 int i, sflags;
859 const char *matchp; /* last p at which a match ended */
860 size_t clen;
861
862 sflags = 0;
863 AT("slow", start, stop, startst, stopst);
864 CLEAR(st);
865 SET1(st, startst);
866 SP("sstart", st, *p);
867 st = step(m->g, startst, stopst, st, NOTHING, st, sflags);
868 if (fast)
869 ASSIGN(fresh, st);
870 matchp = NULL;
871 if (start == m->offp || (start == m->beginp && !(m->eflags&REG_NOTBOL)))
872 c = OUT;
873 else {
874 /*
875 * XXX Wrong if the previous character was multi-byte.
876 * Newline never is (in encodings supported by FreeBSD),
877 * so this only breaks the ISWORD tests below.
878 */
879 c = (uch)*(start - 1);
880 }
881 for (;;) {
882 /* next character */
883 lastc = c;
884 sflags = 0;
885 if (p == m->endp) {
886 c = OUT;
887 clen = 0;
888 } else
889 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
890
891 if (fast && EQ(st, fresh))
892 matchp = p;
893
894 /* is there an EOL and/or BOL between lastc and c? */
895 flagch = '\0';
896 i = 0;
897 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
898 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
899 flagch = BOL;
900 i = m->g->nbol;
901 }
902 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
903 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
904 flagch = (flagch == BOL) ? BOLEOL : EOL;
905 i += m->g->neol;
906 }
907 if (lastc == OUT && (m->eflags & REG_NOTBOL) == 0) {
908 sflags |= SBOS;
909 /* Step one more for BOS. */
910 i++;
911 }
912 if (c == OUT && (m->eflags & REG_NOTEOL) == 0) {
913 sflags |= SEOS;
914 /* Step one more for EOS. */
915 i++;
916 }
917 if (i != 0) {
918 for (; i > 0; i--)
919 st = step(m->g, startst, stopst, st, flagch, st,
920 sflags);
921 SP("sboleol", st, c);
922 }
923
924 /* how about a word boundary? */
925 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
926 (c != OUT && ISWORD(c)) ) {
927 flagch = BOW;
928 }
929 if ( (lastc != OUT && ISWORD(lastc)) &&
930 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
931 flagch = EOW;
932 }
933 if (flagch == BOW || flagch == EOW) {
934 st = step(m->g, startst, stopst, st, flagch, st, sflags);
935 SP("sboweow", st, c);
936 }
937 if (lastc != OUT && c != OUT &&
938 ISWORD(lastc) == ISWORD(c)) {
939 flagch = NWBND;
940 } else if ((lastc == OUT && !ISWORD(c)) ||
941 (c == OUT && !ISWORD(lastc))) {
942 flagch = NWBND;
943 }
944 if (flagch == NWBND) {
945 st = step(m->g, startst, stopst, st, flagch, st, sflags);
946 SP("snwbnd", st, c);
947 }
948
949 /* are we done? */
950 if (ISSET(st, stopst)) {
951 if (fast)
952 break;
953 else
954 matchp = p;
955 }
956 if (EQ(st, empty) || p == stop || clen > (size_t)(stop - p))
957 break; /* NOTE BREAK OUT */
958
959 /* no, we must deal with this character */
960 ASSIGN(tmp, st);
961 if (fast)
962 ASSIGN(st, fresh);
963 else
964 ASSIGN(st, empty);
965 assert(c != OUT);
966 st = step(m->g, startst, stopst, tmp, c, st, sflags);
967 SP("saft", st, c);
968 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st, sflags),
969 st));
970 p += clen;
971 }
972
973 if (fast) {
974 assert(matchp != NULL);
975 m->coldp = matchp;
976 if (ISSET(st, stopst))
977 return (p + XMBRTOWC(NULL, p, stop - p, &m->mbs, 0));
978 else
979 return (NULL);
980 } else
981 return (matchp);
982 }
983
984 /*
985 - step - map set of states reachable before char to set reachable after
986 == static states step(struct re_guts *g, sopno start, sopno stop, \
987 == states bef, int ch, states aft);
988 == #define BOL (OUT-1)
989 == #define EOL (BOL-1)
990 == #define BOLEOL (BOL-2)
991 == #define NOTHING (BOL-3)
992 == #define BOW (BOL-4)
993 == #define EOW (BOL-5)
994 == #define BADCHAR (BOL-6)
995 == #define NONCHAR(c) ((c) <= OUT)
996 */
997 static states
998 step(struct re_guts *g,
999 sopno start, /* start state within strip */
1000 sopno stop, /* state after stop state within strip */
1001 states bef, /* states reachable before */
1002 wint_t ch, /* character or NONCHAR code */
1003 states aft, /* states already known reachable after */
1004 int sflags) /* state flags */
1005 {
1006 cset *cs;
1007 sop s;
1008 sopno pc;
1009 onestate here; /* note, macros know this name */
1010 sopno look;
1011 int i;
1012
1013 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
1014 s = g->strip[pc];
1015 switch (OP(s)) {
1016 case OEND:
1017 assert(pc == stop-1);
1018 break;
1019 case OCHAR:
1020 /* only characters can match */
1021 assert(!NONCHAR(ch) || ch != OPND(s));
1022 if (ch == OPND(s))
1023 FWD(aft, bef, 1);
1024 break;
1025 case OBOS:
1026 if ((ch == BOL || ch == BOLEOL) && (sflags & SBOS) != 0)
1027 FWD(aft, bef, 1);
1028 break;
1029 case OEOS:
1030 if ((ch == EOL || ch == BOLEOL) && (sflags & SEOS) != 0)
1031 FWD(aft, bef, 1);
1032 break;
1033 case OBOL:
1034 if (ch == BOL || ch == BOLEOL)
1035 FWD(aft, bef, 1);
1036 break;
1037 case OEOL:
1038 if (ch == EOL || ch == BOLEOL)
1039 FWD(aft, bef, 1);
1040 break;
1041 case OBOW:
1042 if (ch == BOW)
1043 FWD(aft, bef, 1);
1044 break;
1045 case OEOW:
1046 if (ch == EOW)
1047 FWD(aft, bef, 1);
1048 break;
1049 case OWBND:
1050 if (ch == BOW || ch == EOW)
1051 FWD(aft, bef, 1);
1052 break;
1053 case ONWBND:
1054 if (ch == NWBND)
1055 FWD(aft, aft, 1);
1056 break;
1057 case OANY:
1058 if (!NONCHAR(ch))
1059 FWD(aft, bef, 1);
1060 break;
1061 case OANYOF:
1062 cs = &g->sets[OPND(s)];
1063 if (!NONCHAR(ch) && CHIN(cs, ch))
1064 FWD(aft, bef, 1);
1065 break;
1066 case OBACK_: /* ignored here */
1067 case O_BACK:
1068 FWD(aft, aft, 1);
1069 break;
1070 case OPLUS_: /* forward, this is just an empty */
1071 FWD(aft, aft, 1);
1072 break;
1073 case O_PLUS: /* both forward and back */
1074 FWD(aft, aft, 1);
1075 i = ISSETBACK(aft, OPND(s));
1076 BACK(aft, aft, OPND(s));
1077 if (!i && ISSETBACK(aft, OPND(s))) {
1078 /* oho, must reconsider loop body */
1079 pc -= OPND(s) + 1;
1080 INIT(here, pc);
1081 }
1082 break;
1083 case OQUEST_: /* two branches, both forward */
1084 FWD(aft, aft, 1);
1085 FWD(aft, aft, OPND(s));
1086 break;
1087 case O_QUEST: /* just an empty */
1088 FWD(aft, aft, 1);
1089 break;
1090 case OLPAREN: /* not significant here */
1091 case ORPAREN:
1092 FWD(aft, aft, 1);
1093 break;
1094 case OCH_: /* mark the first two branches */
1095 FWD(aft, aft, 1);
1096 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2);
1097 FWD(aft, aft, OPND(s));
1098 break;
1099 case OOR1: /* done a branch, find the O_CH */
1100 if (ISSTATEIN(aft, here)) {
1101 for (look = 1;
1102 OP(s = g->strip[pc+look]) != (sop)O_CH;
1103 look += OPND(s))
1104 assert(OP(s) == (sop)OOR2);
1105 FWD(aft, aft, look + 1);
1106 }
1107 break;
1108 case OOR2: /* propagate OCH_'s marking */
1109 FWD(aft, aft, 1);
1110 if (OP(g->strip[pc+OPND(s)]) != (sop)O_CH) {
1111 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2);
1112 FWD(aft, aft, OPND(s));
1113 }
1114 break;
1115 case O_CH: /* just empty */
1116 FWD(aft, aft, 1);
1117 break;
1118 default: /* ooooops... */
1119 assert(nope);
1120 break;
1121 }
1122 }
1123
1124 return(aft);
1125 }
1126
1127 #ifdef REDEBUG
1128 /*
1129 - print - print a set of states
1130 == #ifdef REDEBUG
1131 == static void print(struct match *m, const char *caption, states st, \
1132 == int ch, FILE *d);
1133 == #endif
1134 */
1135 static void
1136 print(struct match *m,
1137 const char *caption,
1138 states st,
1139 int ch,
1140 FILE *d)
1141 {
1142 struct re_guts *g = m->g;
1143 sopno i;
1144 int first = 1;
1145
1146 if (!(m->eflags&REG_TRACE))
1147 return;
1148
1149 fprintf(d, "%s", caption);
1150 if (ch != '\0')
1151 fprintf(d, " %s", pchar(ch));
1152 for (i = 0; i < g->nstates; i++)
1153 if (ISSET(st, i)) {
1154 fprintf(d, "%s%lu", (first) ? "\t" : ", ", i);
1155 first = 0;
1156 }
1157 fprintf(d, "\n");
1158 }
1159
1160 /*
1161 - at - print current situation
1162 == #ifdef REDEBUG
1163 == static void at(struct match *m, const char *title, const char *start, \
1164 == const char *stop, sopno startst, sopno stopst);
1165 == #endif
1166 */
1167 static void
1168 at( struct match *m,
1169 const char *title,
1170 const char *start,
1171 const char *stop,
1172 sopno startst,
1173 sopno stopst)
1174 {
1175 if (!(m->eflags&REG_TRACE))
1176 return;
1177
1178 printf("%s %s-", title, pchar(*start));
1179 printf("%s ", pchar(*stop));
1180 printf("%ld-%ld\n", (long)startst, (long)stopst);
1181 }
1182
1183 #ifndef PCHARDONE
1184 #define PCHARDONE /* never again */
1185 /*
1186 - pchar - make a character printable
1187 == #ifdef REDEBUG
1188 == static const char *pchar(int ch);
1189 == #endif
1190 *
1191 * Is this identical to regchar() over in debug.c? Well, yes. But a
1192 * duplicate here avoids having a debugging-capable regexec.o tied to
1193 * a matching debug.o, and this is convenient. It all disappears in
1194 * the non-debug compilation anyway, so it doesn't matter much.
1195 */
1196 static const char * /* -> representation */
1197 pchar(int ch)
1198 {
1199 static char pbuf[10];
1200
1201 if (isprint((uch)ch) || ch == ' ')
1202 sprintf(pbuf, "%c", ch);
1203 else
1204 sprintf(pbuf, "\\%o", ch);
1205 return(pbuf);
1206 }
1207 #endif
1208 #endif
1209
1210 #undef stepback
1211 #undef matcher
1212 #undef walk
1213 #undef dissect
1214 #undef backref
1215 #undef step
1216 #undef print
1217 #undef at
1218 #undef match