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