| blob | ac848bcec882fea319929b4a47afead93a122741 |
1 /*-
2 * This code is derived from OpenBSD's libc/regex, original license follows:
3 *
4 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
5 * Copyright (c) 1992, 1993, 1994
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Henry Spencer.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)engine.c 8.5 (Berkeley) 3/20/94
36 */
38 /*
39 * The matching engine and friends. This file is #included by regexec.c
40 * after suitable #defines of a variety of macros used herein, so that
41 * different state representations can be used without duplicating masses
42 * of code.
43 */
45 #ifdef SNAMES
46 #define matcher smatcher
47 #define fast sfast
48 #define slow sslow
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 #define nope snope
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 #define nope lnope
68 #endif
70 /* another structure passed up and down to avoid zillions of parameters */
71 struct match {
72 struct re_guts *g;
73 int eflags;
74 llvm_regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
75 char *offp; /* offsets work from here */
76 char *beginp; /* start of string -- virtual NUL precedes */
77 char *endp; /* end of string -- virtual NUL here */
78 char *coldp; /* can be no match starting before here */
79 char **lastpos; /* [nplus+1] */
80 STATEVARS;
81 states st; /* current states */
82 states fresh; /* states for a fresh start */
83 states tmp; /* temporary */
84 states empty; /* empty set of states */
85 };
87 static int matcher(struct re_guts *, char *, size_t, llvm_regmatch_t[], int);
88 static char *dissect(struct match *, char *, char *, sopno, sopno);
89 static char *backref(struct match *, char *, char *, sopno, sopno, sopno, int);
90 static char *fast(struct match *, char *, char *, sopno, sopno);
91 static char *slow(struct match *, char *, char *, sopno, sopno);
92 static states step(struct re_guts *, sopno, sopno, states, int, states);
93 #define MAX_RECURSION 100
94 #define BOL (OUT+1)
95 #define EOL (BOL+1)
96 #define BOLEOL (BOL+2)
97 #define NOTHING (BOL+3)
98 #define BOW (BOL+4)
99 #define EOW (BOL+5)
100 #define CODEMAX (BOL+5) /* highest code used */
101 #define NONCHAR(c) ((c) > CHAR_MAX)
102 #define NNONCHAR (CODEMAX-CHAR_MAX)
103 #ifdef REDEBUG
104 static void print(struct match *, char *, states, int, FILE *);
105 #endif
106 #ifdef REDEBUG
107 static void at(struct match *, char *, char *, char *, sopno, sopno);
108 #endif
109 #ifdef REDEBUG
110 static char *pchar(int);
111 #endif
113 #ifdef REDEBUG
114 #define SP(t, s, c) print(m, t, s, c, stdout)
115 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
116 #define NOTE(str) { if (m->eflags®_TRACE) (void)printf("=%s\n", (str)); }
117 static int nope = 0;
118 #else
119 #define SP(t, s, c) /* nothing */
120 #define AT(t, p1, p2, s1, s2) /* nothing */
121 #define NOTE(s) /* nothing */
122 #endif
124 /*
125 - matcher - the actual matching engine
126 */
127 static int /* 0 success, REG_NOMATCH failure */
128 matcher(struct re_guts *g, char *string, size_t nmatch, llvm_regmatch_t pmatch[],
129 int eflags)
130 {
131 char *endp;
132 size_t i;
133 struct match mv;
134 struct match *m = &mv;
135 char *dp;
136 const sopno gf = g->firststate+1; /* +1 for OEND */
137 const sopno gl = g->laststate;
138 char *start;
139 char *stop;
141 /* simplify the situation where possible */
142 if (g->cflags®_NOSUB)
143 nmatch = 0;
144 if (eflags®_STARTEND) {
145 start = string + pmatch[0].rm_so;
146 stop = string + pmatch[0].rm_eo;
147 } else {
148 start = string;
149 stop = start + strlen(start);
150 }
151 if (stop < start)
152 return(REG_INVARG);
154 /* prescreening; this does wonders for this rather slow code */
155 if (g->must != NULL) {
156 for (dp = start; dp < stop; dp++)
157 if (*dp == g->must[0] && stop - dp >= g->mlen &&
158 memcmp(dp, g->must, (size_t)g->mlen) == 0)
159 break;
160 if (dp == stop) /* we didn't find g->must */
161 return(REG_NOMATCH);
162 }
164 /* match struct setup */
165 m->g = g;
166 m->eflags = eflags;
167 m->pmatch = NULL;
168 m->lastpos = NULL;
169 m->offp = string;
170 m->beginp = start;
171 m->endp = stop;
172 STATESETUP(m, 4);
173 SETUP(m->st);
174 SETUP(m->fresh);
175 SETUP(m->tmp);
176 SETUP(m->empty);
177 CLEAR(m->empty);
179 /* this loop does only one repetition except for backrefs */
180 for (;;) {
181 endp = fast(m, start, stop, gf, gl);
182 if (endp == NULL) { /* a miss */
183 free(m->pmatch);
184 free(m->lastpos);
185 STATETEARDOWN(m);
186 return(REG_NOMATCH);
187 }
188 if (nmatch == 0 && !g->backrefs)
189 break; /* no further info needed */
191 /* where? */
192 assert(m->coldp != NULL);
193 for (;;) {
194 NOTE("finding start");
195 endp = slow(m, m->coldp, stop, gf, gl);
196 if (endp != NULL)
197 break;
198 assert(m->coldp < m->endp);
199 m->coldp++;
200 }
201 if (nmatch == 1 && !g->backrefs)
202 break; /* no further info needed */
204 /* oh my, he wants the subexpressions... */
205 if (m->pmatch == NULL)
206 m->pmatch = (llvm_regmatch_t *)malloc((m->g->nsub + 1) *
207 sizeof(llvm_regmatch_t));
208 if (m->pmatch == NULL) {
209 STATETEARDOWN(m);
210 return(REG_ESPACE);
211 }
212 for (i = 1; i <= m->g->nsub; i++)
213 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
214 if (!g->backrefs && !(m->eflags®_BACKR)) {
215 NOTE("dissecting");
216 dp = dissect(m, m->coldp, endp, gf, gl);
217 } else {
218 if (g->nplus > 0 && m->lastpos == NULL)
219 m->lastpos = (char **)malloc((g->nplus+1) *
220 sizeof(char *));
221 if (g->nplus > 0 && m->lastpos == NULL) {
222 free(m->pmatch);
223 STATETEARDOWN(m);
224 return(REG_ESPACE);
225 }
226 NOTE("backref dissect");
227 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
228 }
229 if (dp != NULL)
230 break;
232 /* uh-oh... we couldn't find a subexpression-level match */
233 assert(g->backrefs); /* must be back references doing it */
234 assert(g->nplus == 0 || m->lastpos != NULL);
235 for (;;) {
236 if (dp != NULL || endp <= m->coldp)
237 break; /* defeat */
238 NOTE("backoff");
239 endp = slow(m, m->coldp, endp-1, gf, gl);
240 if (endp == NULL)
241 break; /* defeat */
242 /* try it on a shorter possibility */
243 #ifndef NDEBUG
244 for (i = 1; i <= m->g->nsub; i++) {
245 assert(m->pmatch[i].rm_so == -1);
246 assert(m->pmatch[i].rm_eo == -1);
247 }
248 #endif
249 NOTE("backoff dissect");
250 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
251 }
252 assert(dp == NULL || dp == endp);
253 if (dp != NULL) /* found a shorter one */
254 break;
256 /* despite initial appearances, there is no match here */
257 NOTE("false alarm");
258 if (m->coldp == stop)
259 break;
260 start = m->coldp + 1; /* recycle starting later */
261 }
263 /* fill in the details if requested */
264 if (nmatch > 0) {
265 pmatch[0].rm_so = m->coldp - m->offp;
266 pmatch[0].rm_eo = endp - m->offp;
267 }
268 if (nmatch > 1) {
269 assert(m->pmatch != NULL);
270 for (i = 1; i < nmatch; i++)
271 if (i <= m->g->nsub)
272 pmatch[i] = m->pmatch[i];
273 else {
274 pmatch[i].rm_so = -1;
275 pmatch[i].rm_eo = -1;
276 }
277 }
279 if (m->pmatch != NULL)
280 free((char *)m->pmatch);
281 if (m->lastpos != NULL)
282 free((char *)m->lastpos);
283 STATETEARDOWN(m);
284 return(0);
285 }
287 /*
288 - dissect - figure out what matched what, no back references
289 */
290 static char * /* == stop (success) always */
291 dissect(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
292 {
293 int i;
294 sopno ss; /* start sop of current subRE */
295 sopno es; /* end sop of current subRE */
296 char *sp; /* start of string matched by it */
297 char *stp; /* string matched by it cannot pass here */
298 char *rest; /* start of rest of string */
299 char *tail; /* string unmatched by rest of RE */
300 sopno ssub; /* start sop of subsubRE */
301 sopno esub; /* end sop of subsubRE */
302 char *ssp; /* start of string matched by subsubRE */
303 char *sep; /* end of string matched by subsubRE */
304 char *oldssp; /* previous ssp */
305 char *dp;
307 AT("diss", start, stop, startst, stopst);
308 sp = start;
309 for (ss = startst; ss < stopst; ss = es) {
310 /* identify end of subRE */
311 es = ss;
312 switch (OP(m->g->strip[es])) {
313 case OPLUS_:
314 case OQUEST_:
315 es += OPND(m->g->strip[es]);
316 break;
317 case OCH_:
318 while (OP(m->g->strip[es]) != O_CH)
319 es += OPND(m->g->strip[es]);
320 break;
321 }
322 es++;
324 /* figure out what it matched */
325 switch (OP(m->g->strip[ss])) {
326 case OEND:
327 assert(nope);
328 break;
329 case OCHAR:
330 sp++;
331 break;
332 case OBOL:
333 case OEOL:
334 case OBOW:
335 case OEOW:
336 break;
337 case OANY:
338 case OANYOF:
339 sp++;
340 break;
341 case OBACK_:
342 case O_BACK:
343 assert(nope);
344 break;
345 /* cases where length of match is hard to find */
346 case OQUEST_:
347 stp = stop;
348 for (;;) {
349 /* how long could this one be? */
350 rest = slow(m, sp, stp, ss, es);
351 assert(rest != NULL); /* it did match */
352 /* could the rest match the rest? */
353 tail = slow(m, rest, stop, es, stopst);
354 if (tail == stop)
355 break; /* yes! */
356 /* no -- try a shorter match for this one */
357 stp = rest - 1;
358 assert(stp >= sp); /* it did work */
359 }
360 ssub = ss + 1;
361 esub = es - 1;
362 /* did innards match? */
363 if (slow(m, sp, rest, ssub, esub) != NULL) {
364 dp = dissect(m, sp, rest, ssub, esub);
365 assert(dp == rest);
366 } else /* no */
367 assert(sp == rest);
368 sp = rest;
369 break;
370 case OPLUS_:
371 stp = stop;
372 for (;;) {
373 /* how long could this one be? */
374 rest = slow(m, sp, stp, ss, es);
375 assert(rest != NULL); /* it did match */
376 /* could the rest match the rest? */
377 tail = slow(m, rest, stop, es, stopst);
378 if (tail == stop)
379 break; /* yes! */
380 /* no -- try a shorter match for this one */
381 stp = rest - 1;
382 assert(stp >= sp); /* it did work */
383 }
384 ssub = ss + 1;
385 esub = es - 1;
386 ssp = sp;
387 oldssp = ssp;
388 for (;;) { /* find last match of innards */
389 sep = slow(m, ssp, rest, ssub, esub);
390 if (sep == NULL || sep == ssp)
391 break; /* failed or matched null */
392 oldssp = ssp; /* on to next try */
393 ssp = sep;
394 }
395 if (sep == NULL) {
396 /* last successful match */
397 sep = ssp;
398 ssp = oldssp;
399 }
400 assert(sep == rest); /* must exhaust substring */
401 assert(slow(m, ssp, sep, ssub, esub) == rest);
402 dp = dissect(m, ssp, sep, ssub, esub);
403 assert(dp == sep);
404 sp = rest;
405 break;
406 case OCH_:
407 stp = stop;
408 for (;;) {
409 /* how long could this one be? */
410 rest = slow(m, sp, stp, ss, es);
411 assert(rest != NULL); /* it did match */
412 /* could the rest match the rest? */
413 tail = slow(m, rest, stop, es, stopst);
414 if (tail == stop)
415 break; /* yes! */
416 /* no -- try a shorter match for this one */
417 stp = rest - 1;
418 assert(stp >= sp); /* it did work */
419 }
420 ssub = ss + 1;
421 esub = ss + OPND(m->g->strip[ss]) - 1;
422 assert(OP(m->g->strip[esub]) == OOR1);
423 for (;;) { /* find first matching branch */
424 if (slow(m, sp, rest, ssub, esub) == rest)
425 break; /* it matched all of it */
426 /* that one missed, try next one */
427 assert(OP(m->g->strip[esub]) == OOR1);
428 esub++;
429 assert(OP(m->g->strip[esub]) == OOR2);
430 ssub = esub + 1;
431 esub += OPND(m->g->strip[esub]);
432 if (OP(m->g->strip[esub]) == OOR2)
433 esub--;
434 else
435 assert(OP(m->g->strip[esub]) == O_CH);
436 }
437 dp = dissect(m, sp, rest, ssub, esub);
438 assert(dp == rest);
439 sp = rest;
440 break;
441 case O_PLUS:
442 case O_QUEST:
443 case OOR1:
444 case OOR2:
445 case O_CH:
446 assert(nope);
447 break;
448 case OLPAREN:
449 i = OPND(m->g->strip[ss]);
450 assert(0 < i && i <= m->g->nsub);
451 m->pmatch[i].rm_so = sp - m->offp;
452 break;
453 case ORPAREN:
454 i = OPND(m->g->strip[ss]);
455 assert(0 < i && i <= m->g->nsub);
456 m->pmatch[i].rm_eo = sp - m->offp;
457 break;
458 default: /* uh oh */
459 assert(nope);
460 break;
461 }
462 }
464 assert(sp == stop);
465 return(sp);
466 }
468 /*
469 - backref - figure out what matched what, figuring in back references
470 */
471 static char * /* == stop (success) or NULL (failure) */
472 backref(struct match *m, char *start, char *stop, sopno startst, sopno stopst,
473 sopno lev, int rec) /* PLUS nesting level */
474 {
475 int i;
476 sopno ss; /* start sop of current subRE */
477 char *sp; /* start of string matched by it */
478 sopno ssub; /* start sop of subsubRE */
479 sopno esub; /* end sop of subsubRE */
480 char *ssp; /* start of string matched by subsubRE */
481 char *dp;
482 size_t len;
483 int hard;
484 sop s;
485 llvm_regoff_t offsave;
486 cset *cs;
488 AT("back", start, stop, startst, stopst);
489 sp = start;
491 /* get as far as we can with easy stuff */
492 hard = 0;
493 for (ss = startst; !hard && ss < stopst; ss++)
494 switch (OP(s = m->g->strip[ss])) {
495 case OCHAR:
496 if (sp == stop || *sp++ != (char)OPND(s))
497 return(NULL);
498 break;
499 case OANY:
500 if (sp == stop)
501 return(NULL);
502 sp++;
503 break;
504 case OANYOF:
505 cs = &m->g->sets[OPND(s)];
506 if (sp == stop || !CHIN(cs, *sp++))
507 return(NULL);
508 break;
509 case OBOL:
510 if ( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
511 (sp < m->endp && *(sp-1) == '\n' &&
512 (m->g->cflags®_NEWLINE)) )
513 { /* yes */ }
514 else
515 return(NULL);
516 break;
517 case OEOL:
518 if ( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
519 (sp < m->endp && *sp == '\n' &&
520 (m->g->cflags®_NEWLINE)) )
521 { /* yes */ }
522 else
523 return(NULL);
524 break;
525 case OBOW:
526 if (( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
527 (sp < m->endp && *(sp-1) == '\n' &&
528 (m->g->cflags®_NEWLINE)) ||
529 (sp > m->beginp &&
530 !ISWORD(*(sp-1))) ) &&
531 (sp < m->endp && ISWORD(*sp)) )
532 { /* yes */ }
533 else
534 return(NULL);
535 break;
536 case OEOW:
537 if (( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
538 (sp < m->endp && *sp == '\n' &&
539 (m->g->cflags®_NEWLINE)) ||
540 (sp < m->endp && !ISWORD(*sp)) ) &&
541 (sp > m->beginp && ISWORD(*(sp-1))) )
542 { /* yes */ }
543 else
544 return(NULL);
545 break;
546 case O_QUEST:
547 break;
548 case OOR1: /* matches null but needs to skip */
549 ss++;
550 s = m->g->strip[ss];
551 do {
552 assert(OP(s) == OOR2);
553 ss += OPND(s);
554 } while (OP(s = m->g->strip[ss]) != O_CH);
555 /* note that the ss++ gets us past the O_CH */
556 break;
557 default: /* have to make a choice */
558 hard = 1;
559 break;
560 }
561 if (!hard) { /* that was it! */
562 if (sp != stop)
563 return(NULL);
564 return(sp);
565 }
566 ss--; /* adjust for the for's final increment */
568 /* the hard stuff */
569 AT("hard", sp, stop, ss, stopst);
570 s = m->g->strip[ss];
571 switch (OP(s)) {
572 case OBACK_: /* the vilest depths */
573 i = OPND(s);
574 assert(0 < i && i <= m->g->nsub);
575 if (m->pmatch[i].rm_eo == -1)
576 return(NULL);
577 assert(m->pmatch[i].rm_so != -1);
578 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
579 if (len == 0 && rec++ > MAX_RECURSION)
580 return(NULL);
581 assert(stop - m->beginp >= len);
582 if (sp > stop - len)
583 return(NULL); /* not enough left to match */
584 ssp = m->offp + m->pmatch[i].rm_so;
585 if (memcmp(sp, ssp, len) != 0)
586 return(NULL);
587 while (m->g->strip[ss] != SOP(O_BACK, i))
588 ss++;
589 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
590 break;
591 case OQUEST_: /* to null or not */
592 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
593 if (dp != NULL)
594 return(dp); /* not */
595 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
596 break;
597 case OPLUS_:
598 assert(m->lastpos != NULL);
599 assert(lev+1 <= m->g->nplus);
600 m->lastpos[lev+1] = sp;
601 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
602 break;
603 case O_PLUS:
604 if (sp == m->lastpos[lev]) /* last pass matched null */
605 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
606 /* try another pass */
607 m->lastpos[lev] = sp;
608 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
609 if (dp == NULL)
610 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
611 else
612 return(dp);
613 break;
614 case OCH_: /* find the right one, if any */
615 ssub = ss + 1;
616 esub = ss + OPND(s) - 1;
617 assert(OP(m->g->strip[esub]) == OOR1);
618 for (;;) { /* find first matching branch */
619 dp = backref(m, sp, stop, ssub, esub, lev, rec);
620 if (dp != NULL)
621 return(dp);
622 /* that one missed, try next one */
623 if (OP(m->g->strip[esub]) == O_CH)
624 return(NULL); /* there is none */
625 esub++;
626 assert(OP(m->g->strip[esub]) == OOR2);
627 ssub = esub + 1;
628 esub += OPND(m->g->strip[esub]);
629 if (OP(m->g->strip[esub]) == OOR2)
630 esub--;
631 else
632 assert(OP(m->g->strip[esub]) == O_CH);
633 }
634 break;
635 case OLPAREN: /* must undo assignment if rest fails */
636 i = OPND(s);
637 assert(0 < i && i <= m->g->nsub);
638 offsave = m->pmatch[i].rm_so;
639 m->pmatch[i].rm_so = sp - m->offp;
640 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
641 if (dp != NULL)
642 return(dp);
643 m->pmatch[i].rm_so = offsave;
644 return(NULL);
645 break;
646 case ORPAREN: /* must undo assignment if rest fails */
647 i = OPND(s);
648 assert(0 < i && i <= m->g->nsub);
649 offsave = m->pmatch[i].rm_eo;
650 m->pmatch[i].rm_eo = sp - m->offp;
651 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
652 if (dp != NULL)
653 return(dp);
654 m->pmatch[i].rm_eo = offsave;
655 return(NULL);
656 break;
657 default: /* uh oh */
658 assert(nope);
659 break;
660 }
662 /* "can't happen" */
663 assert(nope);
664 /* NOTREACHED */
665 return NULL;
666 }
668 /*
669 - fast - step through the string at top speed
670 */
671 static char * /* where tentative match ended, or NULL */
672 fast(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
673 {
674 states st = m->st;
675 states fresh = m->fresh;
676 states tmp = m->tmp;
677 char *p = start;
678 int c = (start == m->beginp) ? OUT : *(start-1);
679 int lastc; /* previous c */
680 int flagch;
681 int i;
682 char *coldp; /* last p after which no match was underway */
684 CLEAR(st);
685 SET1(st, startst);
686 st = step(m->g, startst, stopst, st, NOTHING, st);
687 ASSIGN(fresh, st);
688 SP("start", st, *p);
689 coldp = NULL;
690 for (;;) {
691 /* next character */
692 lastc = c;
693 c = (p == m->endp) ? OUT : *p;
694 if (EQ(st, fresh))
695 coldp = p;
697 /* is there an EOL and/or BOL between lastc and c? */
698 flagch = '\0';
699 i = 0;
700 if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
701 (lastc == OUT && !(m->eflags®_NOTBOL)) ) {
702 flagch = BOL;
703 i = m->g->nbol;
704 }
705 if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
706 (c == OUT && !(m->eflags®_NOTEOL)) ) {
707 flagch = (flagch == BOL) ? BOLEOL : EOL;
708 i += m->g->neol;
709 }
710 if (i != 0) {
711 for (; i > 0; i--)
712 st = step(m->g, startst, stopst, st, flagch, st);
713 SP("boleol", st, c);
714 }
716 /* how about a word boundary? */
717 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
718 (c != OUT && ISWORD(c)) ) {
719 flagch = BOW;
720 }
721 if ( (lastc != OUT && ISWORD(lastc)) &&
722 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
723 flagch = EOW;
724 }
725 if (flagch == BOW || flagch == EOW) {
726 st = step(m->g, startst, stopst, st, flagch, st);
727 SP("boweow", st, c);
728 }
730 /* are we done? */
731 if (ISSET(st, stopst) || p == stop)
732 break; /* NOTE BREAK OUT */
734 /* no, we must deal with this character */
735 ASSIGN(tmp, st);
736 ASSIGN(st, fresh);
737 assert(c != OUT);
738 st = step(m->g, startst, stopst, tmp, c, st);
739 SP("aft", st, c);
740 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
741 p++;
742 }
744 assert(coldp != NULL);
745 m->coldp = coldp;
746 if (ISSET(st, stopst))
747 return(p+1);
748 else
749 return(NULL);
750 }
752 /*
753 - slow - step through the string more deliberately
754 */
755 static char * /* where it ended */
756 slow(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
757 {
758 states st = m->st;
759 states empty = m->empty;
760 states tmp = m->tmp;
761 char *p = start;
762 int c = (start == m->beginp) ? OUT : *(start-1);
763 int lastc; /* previous c */
764 int flagch;
765 int i;
766 char *matchp; /* last p at which a match ended */
768 AT("slow", start, stop, startst, stopst);
769 CLEAR(st);
770 SET1(st, startst);
771 SP("sstart", st, *p);
772 st = step(m->g, startst, stopst, st, NOTHING, st);
773 matchp = NULL;
774 for (;;) {
775 /* next character */
776 lastc = c;
777 c = (p == m->endp) ? OUT : *p;
779 /* is there an EOL and/or BOL between lastc and c? */
780 flagch = '\0';
781 i = 0;
782 if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
783 (lastc == OUT && !(m->eflags®_NOTBOL)) ) {
784 flagch = BOL;
785 i = m->g->nbol;
786 }
787 if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
788 (c == OUT && !(m->eflags®_NOTEOL)) ) {
789 flagch = (flagch == BOL) ? BOLEOL : EOL;
790 i += m->g->neol;
791 }
792 if (i != 0) {
793 for (; i > 0; i--)
794 st = step(m->g, startst, stopst, st, flagch, st);
795 SP("sboleol", st, c);
796 }
798 /* how about a word boundary? */
799 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
800 (c != OUT && ISWORD(c)) ) {
801 flagch = BOW;
802 }
803 if ( (lastc != OUT && ISWORD(lastc)) &&
804 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
805 flagch = EOW;
806 }
807 if (flagch == BOW || flagch == EOW) {
808 st = step(m->g, startst, stopst, st, flagch, st);
809 SP("sboweow", st, c);
810 }
812 /* are we done? */
813 if (ISSET(st, stopst))
814 matchp = p;
815 if (EQ(st, empty) || p == stop)
816 break; /* NOTE BREAK OUT */
818 /* no, we must deal with this character */
819 ASSIGN(tmp, st);
820 ASSIGN(st, empty);
821 assert(c != OUT);
822 st = step(m->g, startst, stopst, tmp, c, st);
823 SP("saft", st, c);
824 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
825 p++;
826 }
828 return(matchp);
829 }
832 /*
833 - step - map set of states reachable before char to set reachable after
834 */
835 static states
836 step(struct re_guts *g,
837 sopno start, /* start state within strip */
838 sopno stop, /* state after stop state within strip */
839 states bef, /* states reachable before */
840 int ch, /* character or NONCHAR code */
841 states aft) /* states already known reachable after */
842 {
843 cset *cs;
844 sop s;
845 sopno pc;
846 onestate here; /* note, macros know this name */
847 sopno look;
848 int i;
850 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
851 s = g->strip[pc];
852 switch (OP(s)) {
853 case OEND:
854 assert(pc == stop-1);
855 break;
856 case OCHAR:
857 /* only characters can match */
858 assert(!NONCHAR(ch) || ch != (char)OPND(s));
859 if (ch == (char)OPND(s))
860 FWD(aft, bef, 1);
861 break;
862 case OBOL:
863 if (ch == BOL || ch == BOLEOL)
864 FWD(aft, bef, 1);
865 break;
866 case OEOL:
867 if (ch == EOL || ch == BOLEOL)
868 FWD(aft, bef, 1);
869 break;
870 case OBOW:
871 if (ch == BOW)
872 FWD(aft, bef, 1);
873 break;
874 case OEOW:
875 if (ch == EOW)
876 FWD(aft, bef, 1);
877 break;
878 case OANY:
879 if (!NONCHAR(ch))
880 FWD(aft, bef, 1);
881 break;
882 case OANYOF:
883 cs = &g->sets[OPND(s)];
884 if (!NONCHAR(ch) && CHIN(cs, ch))
885 FWD(aft, bef, 1);
886 break;
887 case OBACK_: /* ignored here */
888 case O_BACK:
889 FWD(aft, aft, 1);
890 break;
891 case OPLUS_: /* forward, this is just an empty */
892 FWD(aft, aft, 1);
893 break;
894 case O_PLUS: /* both forward and back */
895 FWD(aft, aft, 1);
896 i = ISSETBACK(aft, OPND(s));
897 BACK(aft, aft, OPND(s));
898 if (!i && ISSETBACK(aft, OPND(s))) {
899 /* oho, must reconsider loop body */
900 pc -= OPND(s) + 1;
901 INIT(here, pc);
902 }
903 break;
904 case OQUEST_: /* two branches, both forward */
905 FWD(aft, aft, 1);
906 FWD(aft, aft, OPND(s));
907 break;
908 case O_QUEST: /* just an empty */
909 FWD(aft, aft, 1);
910 break;
911 case OLPAREN: /* not significant here */
912 case ORPAREN:
913 FWD(aft, aft, 1);
914 break;
915 case OCH_: /* mark the first two branches */
916 FWD(aft, aft, 1);
917 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
918 FWD(aft, aft, OPND(s));
919 break;
920 case OOR1: /* done a branch, find the O_CH */
921 if (ISSTATEIN(aft, here)) {
922 for (look = 1;
923 OP(s = g->strip[pc+look]) != O_CH;
924 look += OPND(s))
925 assert(OP(s) == OOR2);
926 FWD(aft, aft, look);
927 }
928 break;
929 case OOR2: /* propagate OCH_'s marking */
930 FWD(aft, aft, 1);
931 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
932 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
933 FWD(aft, aft, OPND(s));
934 }
935 break;
936 case O_CH: /* just empty */
937 FWD(aft, aft, 1);
938 break;
939 default: /* ooooops... */
940 assert(nope);
941 break;
942 }
943 }
945 return(aft);
946 }
948 #ifdef REDEBUG
949 /*
950 - print - print a set of states
951 */
952 static void
953 print(struct match *m, char *caption, states st, int ch, FILE *d)
954 {
955 struct re_guts *g = m->g;
956 int i;
957 int first = 1;
959 if (!(m->eflags®_TRACE))
960 return;
962 (void)fprintf(d, "%s", caption);
963 if (ch != '\0')
964 (void)fprintf(d, " %s", pchar(ch));
965 for (i = 0; i < g->nstates; i++)
966 if (ISSET(st, i)) {
967 (void)fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
968 first = 0;
969 }
970 (void)fprintf(d, "\n");
971 }
973 /*
974 - at - print current situation
975 */
976 static void
977 at(struct match *m, char *title, char *start, char *stop, sopno startst,
978 sopno stopst)
979 {
980 if (!(m->eflags®_TRACE))
981 return;
983 (void)printf("%s %s-", title, pchar(*start));
984 (void)printf("%s ", pchar(*stop));
985 (void)printf("%ld-%ld\n", (long)startst, (long)stopst);
986 }
988 #ifndef PCHARDONE
989 #define PCHARDONE /* never again */
990 /*
991 - pchar - make a character printable
992 *
993 * Is this identical to regchar() over in debug.c? Well, yes. But a
994 * duplicate here avoids having a debugging-capable regexec.o tied to
995 * a matching debug.o, and this is convenient. It all disappears in
996 * the non-debug compilation anyway, so it doesn't matter much.
997 */
998 static char * /* -> representation */
999 pchar(int ch)
1000 {
1001 static char pbuf[10];
1003 if (isprint(ch) || ch == ' ')
1004 (void)snprintf(pbuf, sizeof pbuf, "%c", ch);
1005 else
1006 (void)snprintf(pbuf, sizeof pbuf, "\\%o", ch);
1007 return(pbuf);
1008 }
1009 #endif
1010 #endif
1012 #undef matcher
1013 #undef fast
1014 #undef slow
1015 #undef dissect
1016 #undef backref
1017 #undef step
1018 #undef print
1019 #undef at
1020 #undef match
1021 #undef nope