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