1 /*
2 * Copyright 2010 Nexenta Systems, Inc. All rights reserved.
3 * Copyright 2012 Milan Jurik. All rights reserved.
4 * Copyright (c) 2016 by Delphix. All rights reserved.
5 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
6 * Copyright (c) 1992, 1993, 1994
7 * The Regents of the University of California. All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * Henry Spencer.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include <stdbool.h>
38
39 /*
40 * The matching engine and friends. This file is #included by regexec.c
41 * after suitable #defines of a variety of macros used herein, so that
42 * different state representations can be used without duplicating masses
43 * of code.
44 */
45
46 #ifdef SNAMES
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 matcher lmatcher
58 #define walk lwalk
59 #define dissect ldissect
60 #define backref lbackref
61 #define step lstep
62 #define print lprint
63 #define at lat
64 #define match lmat
65 #endif
66 #ifdef MNAMES
67 #define matcher mmatcher
68 #define walk mwalk
69 #define dissect mdissect
70 #define backref mbackref
71 #define step mstep
72 #define print mprint
73 #define at mat
74 #define match mmat
75 #endif
76
77 /* another structure passed up and down to avoid zillions of parameters */
78 struct match {
79 struct re_guts *g;
80 int eflags;
81 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
82 const char *offp; /* offsets work from here */
83 const char *beginp; /* start of string -- virtual NUL precedes */
84 const char *endp; /* end of string -- virtual NUL here */
85 const char *coldp; /* can be no match starting before here */
86 const char **lastpos; /* [nplus+1] */
87 STATEVARS;
88 states st; /* current states */
89 states fresh; /* states for a fresh start */
90 states tmp; /* temporary */
91 states empty; /* empty set of states */
92 mbstate_t mbs; /* multibyte conversion state */
93 };
94
95 /* ========= begin header generated by ./mkh ========= */
96 #ifdef __cplusplus
97 extern "C" {
98 #endif
99
100 /* === engine.c === */
101 static int matcher(struct re_guts *, const char *, size_t, regmatch_t[], int);
102 static const char *dissect(struct match *, const char *, const char *,
103 sopno, sopno);
104 static const char *backref(struct match *, const char *, const char *, sopno,
105 sopno, sopno, int);
106 static const char *walk(struct match *m, const char *start, const char *stop,
107 sopno startst, sopno stopst, bool fast);
108 static states step(struct re_guts *, sopno, sopno, states, wint_t, states);
109 #define MAX_RECURSION 100
110 #define BOL (OUT-1)
111 #define EOL (BOL-1)
112 #define BOLEOL (BOL-2)
113 #define NOTHING (BOL-3)
114 #define BOW (BOL-4)
115 #define EOW (BOL-5)
116 #define BADCHAR (BOL-6)
117 #define NONCHAR(c) ((c) <= OUT)
118 #ifdef REDEBUG
119 static void print(struct match *, const char *, states, int, FILE *);
120 #endif
121 #ifdef REDEBUG
122 static void at(struct match *, const char *, const char *, const char *,
123 sopno, sopno);
124 #endif
125 #ifdef REDEBUG
126 static const char *pchar(int ch);
127 #endif
128
129 #ifdef __cplusplus
130 }
131 #endif
132 /* ========= end header generated by ./mkh ========= */
133
134 #ifdef REDEBUG
135 #define SP(t, s, c) print(m, t, s, c, stdout)
136 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
137 #define NOTE(str) { if (m->eflags®_TRACE) printf("=%s\n", (str)); }
138 #else
139 #define SP(t, s, c) /* nothing */
140 #define AT(t, p1, p2, s1, s2) /* nothing */
141 #define NOTE(s) /* nothing */
142 #endif
143
144 /*
145 * matcher - the actual matching engine
146 */
147 static int /* 0 success, REG_NOMATCH failure */
148 matcher(struct re_guts *g, const char *string, size_t nmatch,
149 regmatch_t pmatch[], int eflags)
150 {
151 const char *endp;
152 size_t i;
153 struct match mv;
154 struct match *m = &mv;
155 const char *dp = NULL;
156 const sopno gf = g->firststate+1; /* +1 for OEND */
157 const sopno gl = g->laststate;
158 const char *start;
159 const char *stop;
160 /* Boyer-Moore algorithms variables */
161 const char *pp;
162 int cj, mj;
163 const char *mustfirst;
164 const char *mustlast;
165 int *matchjump;
166 int *charjump;
167
168 /* simplify the situation where possible */
169 if (g->cflags®_NOSUB)
170 nmatch = 0;
171
172 if (eflags®_STARTEND) {
173 start = string + pmatch[0].rm_so;
174 stop = string + pmatch[0].rm_eo;
175 } else {
176 start = string;
177 stop = start + strlen(start);
178 }
179
180 if (stop < start)
181 return (REG_EFATAL);
182
183 /* prescreening; this does wonders for this rather slow code */
184 if (g->must != NULL) {
185 if (g->charjump != NULL && g->matchjump != NULL) {
186 mustfirst = g->must;
187 mustlast = g->must + g->mlen - 1;
188 charjump = g->charjump;
189 matchjump = g->matchjump;
190 pp = mustlast;
191 for (dp = start+g->mlen-1; dp < stop; ) {
192 /* Fast skip non-matches */
193 while (dp < stop && charjump[(int)*dp])
194 dp += charjump[(int)*dp];
195
196 if (dp >= stop)
197 break;
198
199 /* Greedy matcher */
200 /*
201 * We depend on not being used for
202 * for strings of length 1
203 */
204 while (*--dp == *--pp && pp != mustfirst)
205 ;
206
207 if (*dp == *pp)
208 break;
209
210 /* Jump to next possible match */
211 mj = matchjump[pp - mustfirst];
212 cj = charjump[(int)*dp];
213 dp += (cj < mj ? mj : cj);
214 pp = mustlast;
215 }
216 if (pp != mustfirst)
217 return (REG_NOMATCH);
218 } else {
219 for (dp = start; dp < stop; dp++)
220 if (*dp == g->must[0] &&
221 stop - dp >= g->mlen &&
222 memcmp(dp, g->must, (size_t)g->mlen) == 0)
223 break;
224 if (dp == stop) /* we didn't find g->must */
225 return (REG_NOMATCH);
226 }
227 }
228
229 /* match struct setup */
230 m->g = g;
231 m->eflags = eflags;
232 m->pmatch = NULL;
233 m->lastpos = NULL;
234 m->offp = string;
235 m->beginp = start;
236 m->endp = stop;
237 STATESETUP(m, 4);
238 SETUP(m->st);
239 SETUP(m->fresh);
240 SETUP(m->tmp);
241 SETUP(m->empty);
242 CLEAR(m->empty);
243 ZAPSTATE(&m->mbs);
244
245 /* Adjust start according to moffset, to speed things up */
246 if (dp != NULL && g->moffset > -1)
247 start = ((dp - g->moffset) < start) ? start : dp - g->moffset;
248
249 SP("mloop", m->st, *start);
250
251 /* this loop does only one repetition except for backrefs */
252 for (;;) {
253 endp = walk(m, start, stop, gf, gl, true);
254 if (endp == NULL) { /* a miss */
255 if (m->pmatch != NULL)
256 free((char *)m->pmatch);
257 if (m->lastpos != NULL)
258 free((char *)m->lastpos);
259 STATETEARDOWN(m);
260 return (REG_NOMATCH);
261 }
262 if (nmatch == 0 && !g->backrefs)
263 break; /* no further info needed */
264
265 /* where? */
266 assert(m->coldp != NULL);
267 for (;;) {
268 NOTE("finding start");
269 endp = walk(m, m->coldp, stop, gf, gl, false);
270 if (endp != NULL)
271 break;
272 assert(m->coldp < m->endp);
273 m->coldp += XMBRTOWC(NULL, m->coldp,
274 m->endp - m->coldp, &m->mbs, 0);
275 }
276 if (nmatch == 1 && !g->backrefs)
277 break; /* no further info needed */
278
279 /* oh my, it wants the subexpressions... */
280 if (m->pmatch == NULL)
281 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
282 sizeof (regmatch_t));
283 if (m->pmatch == NULL) {
284 STATETEARDOWN(m);
285 return (REG_ESPACE);
286 }
287 for (i = 1; i <= m->g->nsub; i++)
288 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
289 if (!g->backrefs && !(m->eflags®_BACKR)) {
290 NOTE("dissecting");
291 dp = dissect(m, m->coldp, endp, gf, gl);
292 } else {
293 if (g->nplus > 0 && m->lastpos == NULL)
294 m->lastpos = malloc((g->nplus+1) *
295 sizeof (const char *));
296 if (g->nplus > 0 && m->lastpos == NULL) {
297 free(m->pmatch);
298 STATETEARDOWN(m);
299 return (REG_ESPACE);
300 }
301 NOTE("backref dissect");
302 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
303 }
304 if (dp != NULL)
305 break;
306
307 /* uh-oh... we couldn't find a subexpression-level match */
308 assert(g->backrefs); /* must be back references doing it */
309 assert(g->nplus == 0 || m->lastpos != NULL);
310 for (;;) {
311 if (dp != NULL || endp <= m->coldp)
312 break; /* defeat */
313 NOTE("backoff");
314 endp = walk(m, m->coldp, endp-1, gf, gl, false);
315 if (endp == NULL)
316 break; /* defeat */
317 /* try it on a shorter possibility */
318 #ifndef NDEBUG
319 for (i = 1; i <= m->g->nsub; i++) {
320 assert(m->pmatch[i].rm_so == -1);
321 assert(m->pmatch[i].rm_eo == -1);
322 }
323 #endif
324 NOTE("backoff dissect");
325 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
326 }
327 assert(dp == NULL || dp == endp);
328 if (dp != NULL) /* found a shorter one */
329 break;
330
331 /* despite initial appearances, there is no match here */
332 NOTE("false alarm");
333 /* recycle starting later */
334 start = m->coldp + XMBRTOWC(NULL, m->coldp,
335 stop - m->coldp, &m->mbs, 0);
336 assert(start <= stop);
337 }
338
339 /* fill in the details if requested */
340 if (nmatch > 0) {
341 pmatch[0].rm_so = m->coldp - m->offp;
342 pmatch[0].rm_eo = endp - m->offp;
343 }
344 if (nmatch > 1) {
345 assert(m->pmatch != NULL);
346 for (i = 1; i < nmatch; i++)
347 if (i <= m->g->nsub)
348 pmatch[i] = m->pmatch[i];
349 else {
350 pmatch[i].rm_so = -1;
351 pmatch[i].rm_eo = -1;
352 }
353 }
354
355 if (m->pmatch != NULL)
356 free((char *)m->pmatch);
357 if (m->lastpos != NULL)
358 free((char *)m->lastpos);
359 STATETEARDOWN(m);
360 return (0);
361 }
362
363 /*
364 * dissect - figure out what matched what, no back references
365 */
366 static const char *
367 dissect(struct match *m, const char *start, const char *stop, sopno startst,
368 sopno stopst)
369 {
370 int i;
371 sopno ss; /* start sop of current subRE */
372 sopno es; /* end sop of current subRE */
373 const char *sp; /* start of string matched by it */
374 const char *stp; /* string matched by it cannot pass here */
375 const char *rest; /* start of rest of string */
376 const char *tail; /* string unmatched by rest of RE */
377 sopno ssub; /* start sop of subsubRE */
378 sopno esub; /* end sop of subsubRE */
379 const char *ssp; /* start of string matched by subsubRE */
380 const char *sep; /* end of string matched by subsubRE */
381 const char *oldssp; /* previous ssp */
382 const char *dp;
383
384 (void) dp;
385 AT("diss", start, stop, startst, stopst);
386 sp = start;
387 for (ss = startst; ss < stopst; ss = es) {
388 /* identify end of subRE */
389 es = ss;
390 switch (OP(m->g->strip[es])) {
391 case OPLUS_:
392 case OQUEST_:
393 es += OPND(m->g->strip[es]);
394 break;
395 case OCH_:
396 while (OP(m->g->strip[es]) != (sop)O_CH)
397 es += OPND(m->g->strip[es]);
398 break;
399 }
400 es++;
401
402 /* figure out what it matched */
403 switch (OP(m->g->strip[ss])) {
404 case OEND:
405 assert(0);
406 break;
407 case OCHAR:
408 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
409 break;
410 case OBOL:
411 case OEOL:
412 case OBOW:
413 case OEOW:
414 break;
415 case OANY:
416 case OANYOF:
417 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
418 break;
419 case OBACK_:
420 case O_BACK:
421 assert(0);
422 break;
423 /* cases where length of match is hard to find */
424 case OQUEST_:
425 stp = stop;
426 for (;;) {
427 /* how long could this one be? */
428 rest = walk(m, sp, stp, ss, es, false);
429 assert(rest != NULL); /* it did match */
430 /* could the rest match the rest? */
431 tail = walk(m, rest, stop, es, stopst, false);
432 if (tail == stop)
433 break; /* yes! */
434 /* no -- try a shorter match for this one */
435 stp = rest - 1;
436 assert(stp >= sp); /* it did work */
437 }
438 ssub = ss + 1;
439 esub = es - 1;
440 /* did innards match? */
441 if (walk(m, sp, rest, ssub, esub, false) != NULL) {
442 dp = dissect(m, sp, rest, ssub, esub);
443 assert(dp == rest);
444 } else /* no */
445 assert(sp == rest);
446 sp = rest;
447 break;
448 case OPLUS_:
449 stp = stop;
450 for (;;) {
451 /* how long could this one be? */
452 rest = walk(m, sp, stp, ss, es, false);
453 assert(rest != NULL); /* it did match */
454 /* could the rest match the rest? */
455 tail = walk(m, rest, stop, es, stopst, false);
456 if (tail == stop)
457 break; /* yes! */
458 /* no -- try a shorter match for this one */
459 stp = rest - 1;
460 assert(stp >= sp); /* it did work */
461 }
462 ssub = ss + 1;
463 esub = es - 1;
464 ssp = sp;
465 oldssp = ssp;
466 for (;;) { /* find last match of innards */
467 sep = walk(m, ssp, rest, ssub, esub, false);
468 if (sep == NULL || sep == ssp)
469 break; /* failed or matched null */
470 oldssp = ssp; /* on to next try */
471 ssp = sep;
472 }
473 if (sep == NULL) {
474 /* last successful match */
475 sep = ssp;
476 ssp = oldssp;
477 }
478 assert(sep == rest); /* must exhaust substring */
479 assert(walk(m, ssp, sep, ssub, esub, false) == rest);
480 dp = dissect(m, ssp, sep, ssub, esub);
481 assert(dp == sep);
482 sp = rest;
483 break;
484 case OCH_:
485 stp = stop;
486 for (;;) {
487 /* how long could this one be? */
488 rest = walk(m, sp, stp, ss, es, false);
489 assert(rest != NULL); /* it did match */
490 /* could the rest match the rest? */
491 tail = walk(m, rest, stop, es, stopst, false);
492 if (tail == stop)
493 break; /* yes! */
494 /* no -- try a shorter match for this one */
495 stp = rest - 1;
496 assert(stp >= sp); /* it did work */
497 }
498 ssub = ss + 1;
499 esub = ss + OPND(m->g->strip[ss]) - 1;
500 assert(OP(m->g->strip[esub]) == OOR1);
501 for (;;) { /* find first matching branch */
502 if (walk(m, sp, rest, ssub, esub,
503 false) == rest)
504 break; /* it matched all of it */
505 /* that one missed, try next one */
506 assert(OP(m->g->strip[esub]) == OOR1);
507 esub++;
508 assert(OP(m->g->strip[esub]) == OOR2);
509 ssub = esub + 1;
510 esub += OPND(m->g->strip[esub]);
511 if (OP(m->g->strip[esub]) == (sop)OOR2)
512 esub--;
513 else
514 assert(OP(m->g->strip[esub]) == O_CH);
515 }
516 dp = dissect(m, sp, rest, ssub, esub);
517 assert(dp == rest);
518 sp = rest;
519 break;
520 case O_PLUS:
521 case O_QUEST:
522 case OOR1:
523 case OOR2:
524 case O_CH:
525 assert(0);
526 break;
527 case OLPAREN:
528 i = OPND(m->g->strip[ss]);
529 assert(0 < i && i <= m->g->nsub);
530 m->pmatch[i].rm_so = sp - m->offp;
531 break;
532 case ORPAREN:
533 i = OPND(m->g->strip[ss]);
534 assert(0 < i && i <= m->g->nsub);
535 m->pmatch[i].rm_eo = sp - m->offp;
536 break;
537 default: /* uh oh */
538 assert(0);
539 break;
540 }
541 }
542
543 assert(sp == stop);
544 return (sp);
545 }
546
547 /*
548 * backref - figure out what matched what, figuring in back references
549 */
550 static const char *
551 backref(struct match *m, const char *start, const char *stop, sopno startst,
552 sopno stopst, sopno lev, /* PLUS nesting level */
553 int rec)
554 {
555 int i;
556 sopno ss; /* start sop of current subRE */
557 const char *sp; /* start of string matched by it */
558 sopno ssub; /* start sop of subsubRE */
559 sopno esub; /* end sop of subsubRE */
560 const char *ssp; /* start of string matched by subsubRE */
561 const char *dp;
562 size_t len;
563 int hard;
564 sop s;
565 regoff_t offsave;
566 cset *cs;
567 wint_t wc;
568
569 AT("back", start, stop, startst, stopst);
570 sp = start;
571
572 /* get as far as we can with easy stuff */
573 hard = 0;
574 for (ss = startst; !hard && ss < stopst; ss++)
575 switch (OP(s = m->g->strip[ss])) {
576 case OCHAR:
577 if (sp == stop)
578 return (NULL);
579 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
580 if (wc != OPND(s))
581 return (NULL);
582 break;
583 case OANY:
584 if (sp == stop)
585 return (NULL);
586 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
587 if (wc == BADCHAR)
588 return (NULL);
589 break;
590 case OANYOF:
591 if (sp == stop)
592 return (NULL);
593 cs = &m->g->sets[OPND(s)];
594 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
595 if (wc == BADCHAR || !CHIN(cs, wc))
596 return (NULL);
597 break;
598 case OBOL:
599 if ((sp == m->beginp && !(m->eflags®_NOTBOL)) ||
600 (sp > m->offp && sp < m->endp &&
601 *(sp-1) == '\n' && (m->g->cflags®_NEWLINE))) {
602 break;
603 }
604 return (NULL);
605 case OEOL:
606 if ((sp == m->endp && !(m->eflags®_NOTEOL)) ||
607 (sp < m->endp && *sp == '\n' &&
608 (m->g->cflags®_NEWLINE))) {
609 break;
610 }
611 return (NULL);
612 case OBOW:
613 if (sp < m->endp && ISWORD(*sp) &&
614 ((sp == m->beginp && !(m->eflags®_NOTBOL)) ||
615 (sp > m->offp && !ISWORD(*(sp-1))))) {
616 break;
617 }
618 return (NULL);
619 case OEOW:
620 if (((sp == m->endp && !(m->eflags®_NOTEOL)) ||
621 (sp < m->endp && *sp == '\n' &&
622 (m->g->cflags®_NEWLINE)) ||
623 (sp < m->endp && !ISWORD(*sp))) &&
624 (sp > m->beginp && ISWORD(*(sp-1)))) {
625 break;
626 }
627 return (NULL);
628 case O_QUEST:
629 break;
630 case OOR1: /* matches null but needs to skip */
631 ss++;
632 s = m->g->strip[ss];
633 do {
634 assert(OP(s) == OOR2);
635 ss += OPND(s);
636 } while (OP(s = m->g->strip[ss]) != (sop)O_CH);
637 /* note that the ss++ gets us past the O_CH */
638 break;
639 default: /* have to make a choice */
640 hard = 1;
641 break;
642 }
643 if (!hard) { /* that was it! */
644 if (sp != stop)
645 return (NULL);
646 return (sp);
647 }
648 ss--; /* adjust for the for's final increment */
649
650 /* the hard stuff */
651 AT("hard", sp, stop, ss, stopst);
652 s = m->g->strip[ss];
653 switch (OP(s)) {
654 case OBACK_: /* the vilest depths */
655 i = OPND(s);
656 assert(0 < i && i <= m->g->nsub);
657 if (m->pmatch[i].rm_eo == -1)
658 return (NULL);
659 assert(m->pmatch[i].rm_so != -1);
660 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
661 if (len == 0 && rec++ > MAX_RECURSION)
662 return (NULL);
663 assert(stop - m->beginp >= len);
664 if (sp > stop - len)
665 return (NULL); /* not enough left to match */
666 ssp = m->offp + m->pmatch[i].rm_so;
667 if (memcmp(sp, ssp, len) != 0)
668 return (NULL);
669 while (m->g->strip[ss] != (sop)SOP(O_BACK, i))
670 ss++;
671 return (backref(m, sp+len, stop, ss+1, stopst, lev, rec));
672 case OQUEST_: /* to null or not */
673 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
674 if (dp != NULL)
675 return (dp); /* not */
676 return (backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
677 case OPLUS_:
678 assert(m->lastpos != NULL);
679 assert(lev+1 <= m->g->nplus);
680 m->lastpos[lev+1] = sp;
681 return (backref(m, sp, stop, ss+1, stopst, lev+1, rec));
682 case O_PLUS:
683 if (sp == m->lastpos[lev]) /* last pass matched null */
684 return (backref(m, sp, stop, ss+1, stopst, lev-1, rec));
685 /* try another pass */
686 m->lastpos[lev] = sp;
687 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
688 if (dp == NULL)
689 return (backref(m, sp, stop, ss+1, stopst, lev-1, rec));
690 return (dp);
691 case OCH_: /* find the right one, if any */
692 ssub = ss + 1;
693 esub = ss + OPND(s) - 1;
694 assert(OP(m->g->strip[esub]) == OOR1);
695 for (;;) { /* find first matching branch */
696 dp = backref(m, sp, stop, ssub, esub, lev, rec);
697 if (dp != NULL)
698 return (dp);
699 /* that one missed, try next one */
700 if (OP(m->g->strip[esub]) == (sop)O_CH)
701 return (NULL); /* there is none */
702 esub++;
703 assert(OP(m->g->strip[esub]) == (sop)OOR2);
704 ssub = esub + 1;
705 esub += OPND(m->g->strip[esub]);
706 if (OP(m->g->strip[esub]) == (sop)OOR2)
707 esub--;
708 else
709 assert(OP(m->g->strip[esub]) == O_CH);
710 }
711 /* NOTREACHED */
712 break;
713 case OLPAREN: /* must undo assignment if rest fails */
714 i = OPND(s);
715 assert(0 < i && i <= m->g->nsub);
716 offsave = m->pmatch[i].rm_so;
717 m->pmatch[i].rm_so = sp - m->offp;
718 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
719 if (dp != NULL)
720 return (dp);
721 m->pmatch[i].rm_so = offsave;
722 return (NULL);
723 case ORPAREN: /* must undo assignment if rest fails */
724 i = OPND(s);
725 assert(0 < i && i <= m->g->nsub);
726 offsave = m->pmatch[i].rm_eo;
727 m->pmatch[i].rm_eo = sp - m->offp;
728 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
729 if (dp != NULL)
730 return (dp);
731 m->pmatch[i].rm_eo = offsave;
732 return (NULL);
733 default: /* uh oh */
734 assert(0);
735 break;
736 }
737
738 /* "can't happen" */
739 assert(0);
740 return (NULL);
741 }
742
743 /*
744 * Step through the string either quickly or slowly. Returns where it ended
745 * or NULL.
746 */
747 static const char *
748 walk(struct match *m, const char *start, const char *stop, sopno startst,
749 sopno stopst, bool fast)
750 {
751 states st = m->st;
752 states fresh = m->fresh;
753 states empty = m->empty;
754 states tmp = m->tmp;
755 const char *p = start;
756 wint_t c;
757 wint_t lastc; /* previous c */
758 wint_t flagch;
759 int i;
760 const char *matchp; /* last p at which a match ended */
761 size_t clen;
762
763 AT("slow", start, stop, startst, stopst);
764 CLEAR(st);
765 SET1(st, startst);
766 SP("sstart", st, *p);
767 st = step(m->g, startst, stopst, st, NOTHING, st);
768 if (fast)
769 ASSIGN(fresh, st);
770 matchp = NULL;
771 if (start == m->offp || (start == m->beginp && !(m->eflags®_NOTBOL)))
772 c = OUT;
773 else {
774 /*
775 * XXX Wrong if the previous character was multi-byte.
776 * Newline never is (in encodings supported by FreeBSD),
777 * so this only breaks the ISWORD tests below.
778 */
779 c = (uch)*(start - 1);
780 }
781 for (;;) {
782 /* next character */
783 lastc = c;
784 if (p == m->endp) {
785 c = OUT;
786 clen = 0;
787 } else
788 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
789
790 if (fast && EQ(st, fresh))
791 matchp = p;
792
793 /* is there an EOL and/or BOL between lastc and c? */
794 flagch = '\0';
795 i = 0;
796 if ((lastc == '\n' && m->g->cflags®_NEWLINE) ||
797 (lastc == OUT && !(m->eflags®_NOTBOL))) {
798 flagch = BOL;
799 i = m->g->nbol;
800 }
801 if ((c == '\n' && m->g->cflags®_NEWLINE) ||
802 (c == OUT && !(m->eflags®_NOTEOL))) {
803 flagch = (flagch == BOL) ? BOLEOL : EOL;
804 i += m->g->neol;
805 }
806 if (i != 0) {
807 for (; i > 0; i--)
808 st = step(m->g, startst, stopst, st,
809 flagch, st);
810 SP("sboleol", st, c);
811 }
812
813 /* how about a word boundary? */
814 if ((flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
815 (c != OUT && ISWORD(c))) {
816 flagch = BOW;
817 }
818 if ((lastc != OUT && ISWORD(lastc)) &&
819 (flagch == EOL || (c != OUT && !ISWORD(c)))) {
820 flagch = EOW;
821 }
822 if (flagch == BOW || flagch == EOW) {
823 st = step(m->g, startst, stopst, st, flagch, st);
824 SP("sboweow", st, c);
825 }
826
827 /* are we done? */
828 if (ISSET(st, stopst)) {
829 if (fast)
830 break;
831 else
832 matchp = p;
833 }
834 if (EQ(st, empty) || p == stop || clen > (size_t)(stop - p))
835 break; /* NOTE BREAK OUT */
836
837 /* no, we must deal with this character */
838 ASSIGN(tmp, st);
839 if (fast)
840 ASSIGN(st, fresh);
841 else
842 ASSIGN(st, empty);
843 assert(c != OUT);
844 st = step(m->g, startst, stopst, tmp, c, st);
845 SP("saft", st, c);
846 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
847 p += clen;
848 }
849
850 if (fast) {
851 assert(matchp != NULL);
852 m->coldp = matchp;
853 if (ISSET(st, stopst))
854 return (p + XMBRTOWC(NULL, p, stop - p, &m->mbs, 0));
855 else
856 return (NULL);
857 } else
858 return (matchp);
859 }
860
861 /*
862 * step - map set of states reachable before char to set reachable after
863 */
864 static states
865 step(struct re_guts *g,
866 sopno start, /* start state within strip */
867 sopno stop, /* state after stop state within strip */
868 states bef, /* states reachable before */
869 wint_t ch, /* character or NONCHAR code */
870 states aft) /* states already known reachable after */
871 {
872 cset *cs;
873 sop s;
874 sopno pc;
875 onestate here; /* note, macros know this name */
876 sopno look;
877 int i;
878
879 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
880 s = g->strip[pc];
881 switch (OP(s)) {
882 case OEND:
883 assert(pc == stop-1);
884 break;
885 case OCHAR:
886 /* only characters can match */
887 assert(!NONCHAR(ch) || ch != OPND(s));
888 if (ch == OPND(s))
889 FWD(aft, bef, 1);
890 break;
891 case OBOL:
892 if (ch == BOL || ch == BOLEOL)
893 FWD(aft, bef, 1);
894 break;
895 case OEOL:
896 if (ch == EOL || ch == BOLEOL)
897 FWD(aft, bef, 1);
898 break;
899 case OBOW:
900 if (ch == BOW)
901 FWD(aft, bef, 1);
902 break;
903 case OEOW:
904 if (ch == EOW)
905 FWD(aft, bef, 1);
906 break;
907 case OANY:
908 if (!NONCHAR(ch))
909 FWD(aft, bef, 1);
910 break;
911 case OANYOF:
912 cs = &g->sets[OPND(s)];
913 if (!NONCHAR(ch) && CHIN(cs, ch))
914 FWD(aft, bef, 1);
915 break;
916 case OBACK_: /* ignored here */
917 case O_BACK:
918 FWD(aft, aft, 1);
919 break;
920 case OPLUS_: /* forward, this is just an empty */
921 FWD(aft, aft, 1);
922 break;
923 case O_PLUS: /* both forward and back */
924 FWD(aft, aft, 1);
925 i = ISSETBACK(aft, OPND(s));
926 BACK(aft, aft, OPND(s));
927 if (!i && ISSETBACK(aft, OPND(s))) {
928 /* oho, must reconsider loop body */
929 pc -= OPND(s) + 1;
930 INIT(here, pc);
931 }
932 break;
933 case OQUEST_: /* two branches, both forward */
934 FWD(aft, aft, 1);
935 FWD(aft, aft, OPND(s));
936 break;
937 case O_QUEST: /* just an empty */
938 FWD(aft, aft, 1);
939 break;
940 case OLPAREN: /* not significant here */
941 case ORPAREN:
942 FWD(aft, aft, 1);
943 break;
944 case OCH_: /* mark the first two branches */
945 FWD(aft, aft, 1);
946 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2);
947 FWD(aft, aft, OPND(s));
948 break;
949 case OOR1: /* done a branch, find the O_CH */
950 if (ISSTATEIN(aft, here)) {
951 for (look = 1;
952 OP(s = g->strip[pc+look]) != (sop)O_CH;
953 look += OPND(s))
954 assert(OP(s) == (sop)OOR2);
955 FWD(aft, aft, look + 1);
956 }
957 break;
958 case OOR2: /* propagate OCH_'s marking */
959 FWD(aft, aft, 1);
960 if (OP(g->strip[pc+OPND(s)]) != (sop)O_CH) {
961 assert(OP(g->strip[pc+OPND(s)]) == (sop)OOR2);
962 FWD(aft, aft, OPND(s));
963 }
964 break;
965 case O_CH: /* just empty */
966 FWD(aft, aft, 1);
967 break;
968 default: /* ooooops... */
969 assert(0);
970 break;
971 }
972 }
973
974 return (aft);
975 }
976
977 #ifdef REDEBUG
978 /*
979 * print - print a set of states
980 */
981 static void
982 print(struct match *m, const char *caption, states st, int ch, FILE *d)
983 {
984 struct re_guts *g = m->g;
985 sopno i;
986 int first = 1;
987
988 if (!(m->eflags®_TRACE))
989 return;
990
991 (void) fprintf(d, "%s", caption);
992 if (ch != '\0')
993 (void) fprintf(d, " %s", pchar(ch));
994 for (i = 0; i < g->nstates; i++)
995 if (ISSET(st, i)) {
996 (void) fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
997 first = 0;
998 }
999 (void) fprintf(d, "\n");
1000 }
1001
1002 /*
1003 * at - print current situation
1004 */
1005 static void
1006 at(struct match *m, const char *title, const char *start, const char *stop,
1007 sopno startst, sopno stopst)
1008 {
1009 if (!(m->eflags®_TRACE))
1010 return;
1011
1012 (void) printf("%s %s-", title, pchar(*start));
1013 (void) printf("%s ", pchar(*stop));
1014 (void) printf("%ld-%ld\n", (long)startst, (long)stopst);
1015 }
1016
1017 #ifndef PCHARDONE
1018 #define PCHARDONE /* never again */
1019 /*
1020 * pchar - make a character printable
1021 *
1022 * Is this identical to regchar() over in debug.c? Well, yes. But a
1023 * duplicate here avoids having a debugging-capable regexec.o tied to
1024 * a matching debug.o, and this is convenient. It all disappears in
1025 * the non-debug compilation anyway, so it doesn't matter much.
1026 */
1027 static const char *
1028 pchar(int ch)
1029 {
1030 static char pbuf[10];
1031
1032 if (isprint((uch)ch) || ch == ' ')
1033 (void) sprintf(pbuf, "%c", ch);
1034 else
1035 (void) sprintf(pbuf, "\\%o", ch);
1036 return (pbuf);
1037 }
1038 #endif
1039 #endif
1040
1041 #undef matcher
1042 #undef walk
1043 #undef dissect
1044 #undef backref
1045 #undef step
1046 #undef print
1047 #undef at
1048 #undef match