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[apple/libc.git] / regex / FreeBSD / engine.c
1 /*-
2 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
3 * Copyright (c) 1992, 1993, 1994
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Henry Spencer.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)engine.c 8.5 (Berkeley) 3/20/94
34 */
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD: src/lib/libc/regex/engine.c,v 1.23 2009/09/16 06:32:23 dds Exp $");
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 fast sfast
49 #define slow sslow
50 #define dissect sdissect
51 #define backref sbackref
52 #define step sstep
53 #define print sprint
54 #define at sat
55 #define match smat
56 #endif
57 #ifdef LNAMES
58 #define matcher lmatcher
59 #define fast lfast
60 #define slow lslow
61 #define dissect ldissect
62 #define backref lbackref
63 #define step lstep
64 #define print lprint
65 #define at lat
66 #define match lmat
67 #endif
68 #ifdef MNAMES
69 #define matcher mmatcher
70 #define fast mfast
71 #define slow mslow
72 #define dissect mdissect
73 #define backref mbackref
74 #define step mstep
75 #define print mprint
76 #define at mat
77 #define match mmat
78 #endif
79
80 /* another structure passed up and down to avoid zillions of parameters */
81 struct match {
82 struct re_guts *g;
83 int eflags;
84 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
85 const char *offp; /* offsets work from here */
86 const char *beginp; /* start of string -- virtual NUL precedes */
87 const char *endp; /* end of string -- virtual NUL here */
88 const char *coldp; /* can be no match starting before here */
89 const char **lastpos; /* [nplus+1] */
90 STATEVARS;
91 states st; /* current states */
92 states fresh; /* states for a fresh start */
93 states tmp; /* temporary */
94 states empty; /* empty set of states */
95 mbstate_t mbs; /* multibyte conversion state */
96 };
97
98 /* ========= begin header generated by ./mkh ========= */
99 #ifdef __cplusplus
100 extern "C" {
101 #endif
102
103 /* === engine.c === */
104 static int matcher(struct re_guts *g, const char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
105 static const char *dissect(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst);
106 static const char *backref(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst, sopno lev, int);
107 static const char *fast(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst);
108 static const char *slow(struct match *m, const char *start, const char *stop, sopno startst, sopno stopst);
109 static states step(struct re_guts *g, sopno start, sopno stop, states bef, wint_t ch, states aft);
110 #define MAX_RECURSION 100
111 #define BOL (OUT-1)
112 #define EOL (BOL-1)
113 #define BOLEOL (BOL-2)
114 #define NOTHING (BOL-3)
115 #define BOW (BOL-4)
116 #define EOW (BOL-5)
117 #define BADCHAR (BOL-6)
118 #define NONCHAR(c) ((c) <= OUT)
119 #ifdef REDEBUG
120 static void print(struct match *m, const char *caption, states st, int ch, FILE *d);
121 #endif
122 #ifdef REDEBUG
123 static void at(struct match *m, const char *title, const char *start, const char *stop, sopno startst, sopno stopst);
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&REG_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 == static int matcher(struct re_guts *g, const char *string, \
147 == size_t nmatch, regmatch_t pmatch[], int eflags);
148 */
149 static int /* 0 success, REG_NOMATCH failure */
150 matcher(struct re_guts *g,
151 const char *string,
152 size_t nmatch,
153 regmatch_t pmatch[],
154 int eflags)
155 {
156 const char *endp;
157 int i;
158 struct match mv;
159 struct match *m = &mv;
160 const char *dp;
161 const sopno gf = g->firststate+1; /* +1 for OEND */
162 const sopno gl = g->laststate;
163 const char *start;
164 const char *stop;
165 /* Boyer-Moore algorithms variables */
166 const char *pp;
167 int cj, mj;
168 const char *mustfirst;
169 const char *mustlast;
170 int *matchjump;
171 int *charjump;
172
173 /* simplify the situation where possible */
174 if (g->cflags&REG_NOSUB)
175 nmatch = 0;
176 if (eflags&REG_STARTEND) {
177 start = string + pmatch[0].rm_so;
178 stop = string + pmatch[0].rm_eo;
179 } else {
180 start = string;
181 stop = start + strlen(start);
182 }
183 if (stop < start)
184 return(REG_INVARG);
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 /* We depend on not being used for
204 * for strings of length 1
205 */
206 while (*--dp == *--pp && pp != mustfirst);
207
208 if (*dp == *pp)
209 break;
210
211 /* Jump to next possible match */
212 mj = matchjump[pp - mustfirst];
213 cj = charjump[(int)*dp];
214 dp += (cj < mj ? mj : cj);
215 pp = mustlast;
216 }
217 if (pp != mustfirst)
218 return(REG_NOMATCH);
219 } else {
220 for (dp = start; dp < stop; dp++)
221 if (*dp == g->must[0] &&
222 stop - dp >= g->mlen &&
223 memcmp(dp, g->must, (size_t)g->mlen) == 0)
224 break;
225 if (dp == stop) /* we didn't find g->must */
226 return(REG_NOMATCH);
227 }
228 }
229
230 /* match struct setup */
231 m->g = g;
232 m->eflags = eflags;
233 m->pmatch = NULL;
234 m->lastpos = NULL;
235 m->offp = string;
236 m->beginp = start;
237 m->endp = stop;
238 STATESETUP(m, 4);
239 SETUP(m->st);
240 SETUP(m->fresh);
241 SETUP(m->tmp);
242 SETUP(m->empty);
243 CLEAR(m->empty);
244 ZAPSTATE(&m->mbs);
245
246 /* Adjust start according to moffset, to speed things up */
247 if (g->moffset > -1)
248 start = ((dp - g->moffset) < start) ? start : dp - g->moffset;
249
250 SP("mloop", m->st, *start);
251
252 /* this loop does only one repetition except for backrefs */
253 for (;;) {
254 endp = fast(m, start, stop, gf, gl);
255 if (endp == NULL) { /* a miss */
256 if (m->pmatch != NULL)
257 free((char *)m->pmatch);
258 if (m->lastpos != NULL)
259 free((char *)m->lastpos);
260 STATETEARDOWN(m);
261 return(REG_NOMATCH);
262 }
263 if (nmatch == 0 && !g->backrefs)
264 break; /* no further info needed */
265
266 /* where? */
267 assert(m->coldp != NULL);
268 for (;;) {
269 NOTE("finding start");
270 endp = slow(m, m->coldp, stop, gf, gl);
271 if (endp != NULL)
272 break;
273 assert(m->coldp < m->endp);
274 m->coldp += XMBRTOWC(NULL, m->coldp,
275 m->endp - m->coldp, &m->mbs, 0);
276 }
277 if (nmatch == 1 && !g->backrefs)
278 break; /* no further info needed */
279
280 /* oh my, he wants the subexpressions... */
281 if (m->pmatch == NULL)
282 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
283 sizeof(regmatch_t));
284 if (m->pmatch == NULL) {
285 STATETEARDOWN(m);
286 return(REG_ESPACE);
287 }
288 for (i = 1; i <= m->g->nsub; i++)
289 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
290 if (!g->backrefs && !(m->eflags&REG_BACKR)) {
291 NOTE("dissecting");
292 dp = dissect(m, m->coldp, endp, gf, gl);
293 } else {
294 if (g->nplus > 0 && m->lastpos == NULL)
295 m->lastpos = malloc((g->nplus+1) *
296 sizeof(const char *));
297 if (g->nplus > 0 && m->lastpos == NULL) {
298 free(m->pmatch);
299 STATETEARDOWN(m);
300 return(REG_ESPACE);
301 }
302 NOTE("backref dissect");
303 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
304 }
305 if (dp != NULL)
306 break;
307
308 /* uh-oh... we couldn't find a subexpression-level match */
309 assert(g->backrefs); /* must be back references doing it */
310 assert(g->nplus == 0 || m->lastpos != NULL);
311 for (;;) {
312 if (dp != NULL || endp <= m->coldp)
313 break; /* defeat */
314 NOTE("backoff");
315 endp = slow(m, m->coldp, endp-1, gf, gl);
316 if (endp == NULL)
317 break; /* defeat */
318 /* try it on a shorter possibility */
319 #ifndef NDEBUG
320 for (i = 1; i <= m->g->nsub; i++) {
321 assert(m->pmatch[i].rm_so == -1);
322 assert(m->pmatch[i].rm_eo == -1);
323 }
324 #endif
325 NOTE("backoff dissect");
326 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
327 }
328 assert(dp == NULL || dp == endp);
329 if (dp != NULL) /* found a shorter one */
330 break;
331
332 /* despite initial appearances, there is no match here */
333 NOTE("false alarm");
334 /* recycle starting later */
335 start = m->coldp + XMBRTOWC(NULL, m->coldp,
336 stop - m->coldp, &m->mbs, 0);
337 assert(start <= stop);
338 }
339
340 /* fill in the details if requested */
341 if (nmatch > 0) {
342 pmatch[0].rm_so = m->coldp - m->offp;
343 pmatch[0].rm_eo = endp - m->offp;
344 }
345 if (nmatch > 1) {
346 assert(m->pmatch != NULL);
347 for (i = 1; i < nmatch; i++)
348 if (i <= m->g->nsub)
349 pmatch[i] = m->pmatch[i];
350 else {
351 pmatch[i].rm_so = -1;
352 pmatch[i].rm_eo = -1;
353 }
354 }
355
356 if (m->pmatch != NULL)
357 free((char *)m->pmatch);
358 if (m->lastpos != NULL)
359 free((char *)m->lastpos);
360 STATETEARDOWN(m);
361 return(0);
362 }
363
364 /*
365 - dissect - figure out what matched what, no back references
366 == static const char *dissect(struct match *m, const char *start, \
367 == const char *stop, sopno startst, sopno stopst);
368 */
369 static const char * /* == stop (success) always */
370 dissect(struct match *m,
371 const char *start,
372 const char *stop,
373 sopno startst,
374 sopno stopst)
375 {
376 int i;
377 sopno ss; /* start sop of current subRE */
378 sopno es; /* end sop of current subRE */
379 const char *sp; /* start of string matched by it */
380 const char *stp; /* string matched by it cannot pass here */
381 const char *rest; /* start of rest of string */
382 const char *tail; /* string unmatched by rest of RE */
383 sopno ssub; /* start sop of subsubRE */
384 sopno esub; /* end sop of subsubRE */
385 const char *ssp; /* start of string matched by subsubRE */
386 const char *sep; /* end of string matched by subsubRE */
387 const char *oldssp; /* previous ssp */
388 const char *dp;
389
390 AT("diss", start, stop, startst, stopst);
391 sp = start;
392 for (ss = startst; ss < stopst; ss = es) {
393 /* identify end of subRE */
394 es = ss;
395 switch (OP(m->g->strip[es])) {
396 case OPLUS_:
397 case OQUEST_:
398 es += OPND(m->g->strip[es]);
399 break;
400 case OCH_:
401 while (OP(m->g->strip[es]) != O_CH)
402 es += OPND(m->g->strip[es]);
403 break;
404 }
405 es++;
406
407 /* figure out what it matched */
408 switch (OP(m->g->strip[ss])) {
409 case OEND:
410 assert(nope);
411 break;
412 case OCHAR:
413 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
414 break;
415 case OBOL:
416 case OEOL:
417 case OBOW:
418 case OEOW:
419 break;
420 case OANY:
421 case OANYOF:
422 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
423 break;
424 case OBACK_:
425 case O_BACK:
426 assert(nope);
427 break;
428 /* cases where length of match is hard to find */
429 case OQUEST_:
430 stp = stop;
431 for (;;) {
432 /* how long could this one be? */
433 rest = slow(m, sp, stp, ss, es);
434 assert(rest != NULL); /* it did match */
435 /* could the rest match the rest? */
436 tail = slow(m, rest, stop, es, stopst);
437 if (tail == stop)
438 break; /* yes! */
439 /* no -- try a shorter match for this one */
440 stp = rest - 1;
441 assert(stp >= sp); /* it did work */
442 }
443 ssub = ss + 1;
444 esub = es - 1;
445 /* did innards match? */
446 if (slow(m, sp, rest, ssub, esub) != NULL) {
447 dp = dissect(m, sp, rest, ssub, esub);
448 assert(dp == rest);
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(nope);
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(nope);
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 == static const char *backref(struct match *m, const char *start, \
554 == const char *stop, sopno startst, sopno stopst, sopno lev);
555 */
556 static const char * /* == stop (success) or NULL (failure) */
557 backref(struct match *m,
558 const char *start,
559 const char *stop,
560 sopno startst,
561 sopno stopst,
562 sopno lev, /* PLUS nesting level */
563 int rec)
564 {
565 int i;
566 sopno ss; /* start sop of current subRE */
567 const char *sp; /* start of string matched by it */
568 sopno ssub; /* start sop of subsubRE */
569 sopno esub; /* end sop of subsubRE */
570 const char *ssp; /* start of string matched by subsubRE */
571 const char *dp;
572 size_t len;
573 int hard;
574 sop s;
575 regoff_t offsave;
576 cset *cs;
577 wint_t wc;
578
579 AT("back", start, stop, startst, stopst);
580 sp = start;
581
582 /* get as far as we can with easy stuff */
583 hard = 0;
584 for (ss = startst; !hard && ss < stopst; ss++)
585 switch (OP(s = m->g->strip[ss])) {
586 case OCHAR:
587 if (sp == stop)
588 return(NULL);
589 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
590 if (wc != OPND(s))
591 return(NULL);
592 break;
593 case OANY:
594 if (sp == stop)
595 return(NULL);
596 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
597 if (wc == BADCHAR)
598 return (NULL);
599 break;
600 case OANYOF:
601 if (sp == stop)
602 return (NULL);
603 cs = &m->g->sets[OPND(s)];
604 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
605 if (wc == BADCHAR || !CHIN(cs, wc))
606 return(NULL);
607 break;
608 case OBOL:
609 if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
610 (sp < m->endp && *(sp-1) == '\n' &&
611 (m->g->cflags&REG_NEWLINE)) )
612 { /* yes */ }
613 else
614 return(NULL);
615 break;
616 case OEOL:
617 if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
618 (sp < m->endp && *sp == '\n' &&
619 (m->g->cflags&REG_NEWLINE)) )
620 { /* yes */ }
621 else
622 return(NULL);
623 break;
624 case OBOW:
625 if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
626 (sp < m->endp && *(sp-1) == '\n' &&
627 (m->g->cflags&REG_NEWLINE)) ||
628 (sp > m->beginp &&
629 !ISWORD(*(sp-1))) ) &&
630 (sp < m->endp && ISWORD(*sp)) )
631 { /* yes */ }
632 else
633 return(NULL);
634 break;
635 case OEOW:
636 if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
637 (sp < m->endp && *sp == '\n' &&
638 (m->g->cflags&REG_NEWLINE)) ||
639 (sp < m->endp && !ISWORD(*sp)) ) &&
640 (sp > m->beginp && ISWORD(*(sp-1))) )
641 { /* yes */ }
642 else
643 return(NULL);
644 break;
645 case O_QUEST:
646 break;
647 case OOR1: /* matches null but needs to skip */
648 ss++;
649 s = m->g->strip[ss];
650 do {
651 assert(OP(s) == OOR2);
652 ss += OPND(s);
653 } while (OP(s = m->g->strip[ss]) != O_CH);
654 /* note that the ss++ gets us past the O_CH */
655 break;
656 default: /* have to make a choice */
657 hard = 1;
658 break;
659 }
660 if (!hard) { /* that was it! */
661 if (sp != stop)
662 return(NULL);
663 return(sp);
664 }
665 ss--; /* adjust for the for's final increment */
666
667 /* the hard stuff */
668 AT("hard", sp, stop, ss, stopst);
669 s = m->g->strip[ss];
670 switch (OP(s)) {
671 case OBACK_: /* the vilest depths */
672 i = OPND(s);
673 assert(0 < i && i <= m->g->nsub);
674 if (m->pmatch[i].rm_eo == -1)
675 return(NULL);
676 assert(m->pmatch[i].rm_so != -1);
677 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
678 if (len == 0 && rec++ > MAX_RECURSION)
679 return(NULL);
680 assert(stop - m->beginp >= len);
681 if (sp > stop - len)
682 return(NULL); /* not enough left to match */
683 ssp = m->offp + m->pmatch[i].rm_so;
684 if (memcmp(sp, ssp, len) != 0)
685 return(NULL);
686 while (m->g->strip[ss] != SOP(O_BACK, i))
687 ss++;
688 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
689 break;
690 case OQUEST_: /* to null or not */
691 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
692 if (dp != NULL)
693 return(dp); /* not */
694 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
695 break;
696 case OPLUS_:
697 assert(m->lastpos != NULL);
698 assert(lev+1 <= m->g->nplus);
699 m->lastpos[lev+1] = sp;
700 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
701 break;
702 case O_PLUS:
703 if (sp == m->lastpos[lev]) /* last pass matched null */
704 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
705 /* try another pass */
706 m->lastpos[lev] = sp;
707 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
708 if (dp == NULL)
709 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
710 else
711 return(dp);
712 break;
713 case OCH_: /* find the right one, if any */
714 ssub = ss + 1;
715 esub = ss + OPND(s) - 1;
716 assert(OP(m->g->strip[esub]) == OOR1);
717 for (;;) { /* find first matching branch */
718 dp = backref(m, sp, stop, ssub, esub, lev, rec);
719 if (dp != NULL)
720 return(dp);
721 /* that one missed, try next one */
722 if (OP(m->g->strip[esub]) == O_CH)
723 return(NULL); /* there is none */
724 esub++;
725 assert(OP(m->g->strip[esub]) == OOR2);
726 ssub = esub + 1;
727 esub += OPND(m->g->strip[esub]);
728 if (OP(m->g->strip[esub]) == OOR2)
729 esub--;
730 else
731 assert(OP(m->g->strip[esub]) == O_CH);
732 }
733 break;
734 case OLPAREN: /* must undo assignment if rest fails */
735 i = OPND(s);
736 assert(0 < i && i <= m->g->nsub);
737 offsave = m->pmatch[i].rm_so;
738 m->pmatch[i].rm_so = sp - m->offp;
739 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
740 if (dp != NULL)
741 return(dp);
742 m->pmatch[i].rm_so = offsave;
743 return(NULL);
744 break;
745 case ORPAREN: /* must undo assignment if rest fails */
746 i = OPND(s);
747 assert(0 < i && i <= m->g->nsub);
748 offsave = m->pmatch[i].rm_eo;
749 m->pmatch[i].rm_eo = sp - m->offp;
750 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
751 if (dp != NULL)
752 return(dp);
753 m->pmatch[i].rm_eo = offsave;
754 return(NULL);
755 break;
756 default: /* uh oh */
757 assert(nope);
758 break;
759 }
760
761 /* "can't happen" */
762 assert(nope);
763 /* NOTREACHED */
764 return "shut up gcc";
765 }
766
767 /*
768 - fast - step through the string at top speed
769 == static const char *fast(struct match *m, const char *start, \
770 == const char *stop, sopno startst, sopno stopst);
771 */
772 static const char * /* where tentative match ended, or NULL */
773 fast( struct match *m,
774 const char *start,
775 const char *stop,
776 sopno startst,
777 sopno stopst)
778 {
779 states st = m->st;
780 states fresh = m->fresh;
781 states tmp = m->tmp;
782 const char *p = start;
783 wint_t c;
784 wint_t lastc; /* previous c */
785 wint_t flagch;
786 int i;
787 const char *coldp; /* last p after which no match was underway */
788 size_t clen;
789
790 CLEAR(st);
791 SET1(st, startst);
792 SP("fast", st, *p);
793 st = step(m->g, startst, stopst, st, NOTHING, st);
794 ASSIGN(fresh, st);
795 SP("start", st, *p);
796 coldp = NULL;
797 if (start == m->beginp)
798 c = OUT;
799 else {
800 /*
801 * XXX Wrong if the previous character was multi-byte.
802 * Newline never is (in encodings supported by FreeBSD),
803 * so this only breaks the ISWORD tests below.
804 */
805 c = (uch)*(start - 1);
806 }
807 for (;;) {
808 /* next character */
809 lastc = c;
810 if (p == m->endp) {
811 clen = 0;
812 c = OUT;
813 } else
814 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
815 if (EQ(st, fresh))
816 coldp = p;
817
818 /* is there an EOL and/or BOL between lastc and c? */
819 flagch = '\0';
820 i = 0;
821 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
822 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
823 flagch = BOL;
824 i = m->g->nbol;
825 }
826 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
827 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
828 flagch = (flagch == BOL) ? BOLEOL : EOL;
829 i += m->g->neol;
830 }
831 if (i != 0) {
832 for (; i > 0; i--)
833 st = step(m->g, startst, stopst, st, flagch, st);
834 SP("boleol", st, c);
835 }
836
837 /* how about a word boundary? */
838 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
839 (c != OUT && ISWORD(c)) ) {
840 flagch = BOW;
841 }
842 if ( (lastc != OUT && ISWORD(lastc)) &&
843 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
844 flagch = EOW;
845 }
846 if (flagch == BOW || flagch == EOW) {
847 st = step(m->g, startst, stopst, st, flagch, st);
848 SP("boweow", st, c);
849 }
850
851 /* are we done? */
852 if (ISSET(st, stopst) || p == stop || clen > stop - p)
853 break; /* NOTE BREAK OUT */
854
855 /* no, we must deal with this character */
856 ASSIGN(tmp, st);
857 ASSIGN(st, fresh);
858 assert(c != OUT);
859 st = step(m->g, startst, stopst, tmp, c, st);
860 SP("aft", st, c);
861 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
862 p += clen;
863 }
864
865 assert(coldp != NULL);
866 m->coldp = coldp;
867 if (ISSET(st, stopst))
868 return(p+XMBRTOWC(NULL, p, stop - p, &m->mbs, 0));
869 else
870 return(NULL);
871 }
872
873 /*
874 - slow - step through the string more deliberately
875 == static const char *slow(struct match *m, const char *start, \
876 == const char *stop, sopno startst, sopno stopst);
877 */
878 static const char * /* where it ended */
879 slow( struct match *m,
880 const char *start,
881 const char *stop,
882 sopno startst,
883 sopno stopst)
884 {
885 states st = m->st;
886 states empty = m->empty;
887 states tmp = m->tmp;
888 const char *p = start;
889 wint_t c;
890 wint_t lastc; /* previous c */
891 wint_t flagch;
892 int i;
893 const char *matchp; /* last p at which a match ended */
894 size_t clen;
895
896 AT("slow", start, stop, startst, stopst);
897 CLEAR(st);
898 SET1(st, startst);
899 SP("sstart", st, *p);
900 st = step(m->g, startst, stopst, st, NOTHING, st);
901 matchp = NULL;
902 if (start == m->beginp)
903 c = OUT;
904 else {
905 /*
906 * XXX Wrong if the previous character was multi-byte.
907 * Newline never is (in encodings supported by FreeBSD),
908 * so this only breaks the ISWORD tests below.
909 */
910 c = (uch)*(start - 1);
911 }
912 for (;;) {
913 /* next character */
914 lastc = c;
915 if (p == m->endp) {
916 c = OUT;
917 clen = 0;
918 } else
919 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
920
921 /* is there an EOL and/or BOL between lastc and c? */
922 flagch = '\0';
923 i = 0;
924 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
925 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
926 flagch = BOL;
927 i = m->g->nbol;
928 }
929 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
930 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
931 flagch = (flagch == BOL) ? BOLEOL : EOL;
932 i += m->g->neol;
933 }
934 if (i != 0) {
935 for (; i > 0; i--)
936 st = step(m->g, startst, stopst, st, flagch, st);
937 SP("sboleol", st, c);
938 }
939
940 /* how about a word boundary? */
941 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
942 (c != OUT && ISWORD(c)) ) {
943 flagch = BOW;
944 }
945 if ( (lastc != OUT && ISWORD(lastc)) &&
946 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
947 flagch = EOW;
948 }
949 if (flagch == BOW || flagch == EOW) {
950 st = step(m->g, startst, stopst, st, flagch, st);
951 SP("sboweow", st, c);
952 }
953
954 /* are we done? */
955 if (ISSET(st, stopst))
956 matchp = p;
957 if (EQ(st, empty) || p == stop || clen > stop - p)
958 break; /* NOTE BREAK OUT */
959
960 /* no, we must deal with this character */
961 ASSIGN(tmp, st);
962 ASSIGN(st, empty);
963 assert(c != OUT);
964 st = step(m->g, startst, stopst, tmp, c, st);
965 SP("saft", st, c);
966 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
967 p += clen;
968 }
969
970 return(matchp);
971 }
972
973
974 /*
975 - step - map set of states reachable before char to set reachable after
976 == static states step(struct re_guts *g, sopno start, sopno stop, \
977 == states bef, int ch, states aft);
978 == #define BOL (OUT-1)
979 == #define EOL (BOL-1)
980 == #define BOLEOL (BOL-2)
981 == #define NOTHING (BOL-3)
982 == #define BOW (BOL-4)
983 == #define EOW (BOL-5)
984 == #define BADCHAR (BOL-6)
985 == #define NONCHAR(c) ((c) <= OUT)
986 */
987 static states
988 step(struct re_guts *g,
989 sopno start, /* start state within strip */
990 sopno stop, /* state after stop state within strip */
991 states bef, /* states reachable before */
992 wint_t ch, /* character or NONCHAR code */
993 states aft) /* states already known reachable after */
994 {
995 cset *cs;
996 sop s;
997 sopno pc;
998 onestate here; /* note, macros know this name */
999 sopno look;
1000 int i;
1001
1002 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
1003 s = g->strip[pc];
1004 switch (OP(s)) {
1005 case OEND:
1006 assert(pc == stop-1);
1007 break;
1008 case OCHAR:
1009 /* only characters can match */
1010 assert(!NONCHAR(ch) || ch != OPND(s));
1011 if (ch == OPND(s))
1012 FWD(aft, bef, 1);
1013 break;
1014 case OBOL:
1015 if (ch == BOL || ch == BOLEOL)
1016 FWD(aft, bef, 1);
1017 break;
1018 case OEOL:
1019 if (ch == EOL || ch == BOLEOL)
1020 FWD(aft, bef, 1);
1021 break;
1022 case OBOW:
1023 if (ch == BOW)
1024 FWD(aft, bef, 1);
1025 break;
1026 case OEOW:
1027 if (ch == EOW)
1028 FWD(aft, bef, 1);
1029 break;
1030 case OANY:
1031 if (!NONCHAR(ch))
1032 FWD(aft, bef, 1);
1033 break;
1034 case OANYOF:
1035 cs = &g->sets[OPND(s)];
1036 if (!NONCHAR(ch) && CHIN(cs, ch))
1037 FWD(aft, bef, 1);
1038 break;
1039 case OBACK_: /* ignored here */
1040 case O_BACK:
1041 FWD(aft, aft, 1);
1042 break;
1043 case OPLUS_: /* forward, this is just an empty */
1044 FWD(aft, aft, 1);
1045 break;
1046 case O_PLUS: /* both forward and back */
1047 FWD(aft, aft, 1);
1048 i = ISSETBACK(aft, OPND(s));
1049 BACK(aft, aft, OPND(s));
1050 if (!i && ISSETBACK(aft, OPND(s))) {
1051 /* oho, must reconsider loop body */
1052 pc -= OPND(s) + 1;
1053 INIT(here, pc);
1054 }
1055 break;
1056 case OQUEST_: /* two branches, both forward */
1057 FWD(aft, aft, 1);
1058 FWD(aft, aft, OPND(s));
1059 break;
1060 case O_QUEST: /* just an empty */
1061 FWD(aft, aft, 1);
1062 break;
1063 case OLPAREN: /* not significant here */
1064 case ORPAREN:
1065 FWD(aft, aft, 1);
1066 break;
1067 case OCH_: /* mark the first two branches */
1068 FWD(aft, aft, 1);
1069 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1070 FWD(aft, aft, OPND(s));
1071 break;
1072 case OOR1: /* done a branch, find the O_CH */
1073 if (ISSTATEIN(aft, here)) {
1074 for (look = 1;
1075 OP(s = g->strip[pc+look]) != O_CH;
1076 look += OPND(s))
1077 assert(OP(s) == OOR2);
1078 FWD(aft, aft, look + 1);
1079 }
1080 break;
1081 case OOR2: /* propagate OCH_'s marking */
1082 FWD(aft, aft, 1);
1083 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
1084 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1085 FWD(aft, aft, OPND(s));
1086 }
1087 break;
1088 case O_CH: /* just empty */
1089 FWD(aft, aft, 1);
1090 break;
1091 default: /* ooooops... */
1092 assert(nope);
1093 break;
1094 }
1095 }
1096
1097 return(aft);
1098 }
1099
1100 #ifdef REDEBUG
1101 /*
1102 - print - print a set of states
1103 == #ifdef REDEBUG
1104 == static void print(struct match *m, const char *caption, states st, \
1105 == int ch, FILE *d);
1106 == #endif
1107 */
1108 static void
1109 print(struct match *m,
1110 const char *caption,
1111 states st,
1112 int ch,
1113 FILE *d)
1114 {
1115 struct re_guts *g = m->g;
1116 int i;
1117 int first = 1;
1118
1119 if (!(m->eflags&REG_TRACE))
1120 return;
1121
1122 fprintf(d, "%s", caption);
1123 if (ch != '\0')
1124 fprintf(d, " %s", pchar(ch));
1125 for (i = 0; i < g->nstates; i++)
1126 if (ISSET(st, i)) {
1127 fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
1128 first = 0;
1129 }
1130 fprintf(d, "\n");
1131 }
1132
1133 /*
1134 - at - print current situation
1135 == #ifdef REDEBUG
1136 == static void at(struct match *m, const char *title, const char *start, \
1137 == const char *stop, sopno startst, sopno stopst);
1138 == #endif
1139 */
1140 static void
1141 at( struct match *m,
1142 const char *title,
1143 const char *start,
1144 const char *stop,
1145 sopno startst,
1146 sopno stopst)
1147 {
1148 if (!(m->eflags&REG_TRACE))
1149 return;
1150
1151 printf("%s %s-", title, pchar(*start));
1152 printf("%s ", pchar(*stop));
1153 printf("%ld-%ld\n", (long)startst, (long)stopst);
1154 }
1155
1156 #ifndef PCHARDONE
1157 #define PCHARDONE /* never again */
1158 /*
1159 - pchar - make a character printable
1160 == #ifdef REDEBUG
1161 == static const char *pchar(int ch);
1162 == #endif
1163 *
1164 * Is this identical to regchar() over in debug.c? Well, yes. But a
1165 * duplicate here avoids having a debugging-capable regexec.o tied to
1166 * a matching debug.o, and this is convenient. It all disappears in
1167 * the non-debug compilation anyway, so it doesn't matter much.
1168 */
1169 static const char * /* -> representation */
1170 pchar(int ch)
1171 {
1172 static char pbuf[10];
1173
1174 if (isprint((uch)ch) || ch == ' ')
1175 sprintf(pbuf, "%c", ch);
1176 else
1177 sprintf(pbuf, "\\%o", ch);
1178 return(pbuf);
1179 }
1180 #endif
1181 #endif
1182
1183 #undef matcher
1184 #undef fast
1185 #undef slow
1186 #undef dissect
1187 #undef backref
1188 #undef step
1189 #undef print
1190 #undef at
1191 #undef match
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