source: vendor/FreeBSD-libc/5.1/regex/engine.c

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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 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)engine.c 8.5 (Berkeley) 3/20/94
38 */
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: src/lib/libc/regex/engine.c,v 1.13 2003/02/16 17:29:10 nectar Exp $");
42
43/*
44 * The matching engine and friends. This file is #included by regexec.c
45 * after suitable #defines of a variety of macros used herein, so that
46 * different state representations can be used without duplicating masses
47 * of code.
48 */
49
50#ifdef SNAMES
51#define matcher smatcher
52#define fast sfast
53#define slow sslow
54#define dissect sdissect
55#define backref sbackref
56#define step sstep
57#define print sprint
58#define at sat
59#define match smat
60#endif
61#ifdef LNAMES
62#define matcher lmatcher
63#define fast lfast
64#define slow lslow
65#define dissect ldissect
66#define backref lbackref
67#define step lstep
68#define print lprint
69#define at lat
70#define match lmat
71#endif
72
73/* another structure passed up and down to avoid zillions of parameters */
74struct match {
75 struct re_guts *g;
76 int eflags;
77 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
78 char *offp; /* offsets work from here */
79 char *beginp; /* start of string -- virtual NUL precedes */
80 char *endp; /* end of string -- virtual NUL here */
81 char *coldp; /* can be no match starting before here */
82 char **lastpos; /* [nplus+1] */
83 STATEVARS;
84 states st; /* current states */
85 states fresh; /* states for a fresh start */
86 states tmp; /* temporary */
87 states empty; /* empty set of states */
88};
89
90/* ========= begin header generated by ./mkh ========= */
91#ifdef __cplusplus
92extern "C" {
93#endif
94
95/* === engine.c === */
96static int matcher(struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
97static char *dissect(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
98static char *backref(struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev);
99static char *fast(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
100static char *slow(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
101static states step(struct re_guts *g, sopno start, sopno stop, states bef, int ch, states aft);
102#define BOL (OUT+1)
103#define EOL (BOL+1)
104#define BOLEOL (BOL+2)
105#define NOTHING (BOL+3)
106#define BOW (BOL+4)
107#define EOW (BOL+5)
108#define CODEMAX (BOL+5) /* highest code used */
109#define NONCHAR(c) ((c) > CHAR_MAX)
110#define NNONCHAR (CODEMAX-CHAR_MAX)
111#ifdef REDEBUG
112static void print(struct match *m, char *caption, states st, int ch, FILE *d);
113#endif
114#ifdef REDEBUG
115static void at(struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst);
116#endif
117#ifdef REDEBUG
118static char *pchar(int ch);
119#endif
120
121#ifdef __cplusplus
122}
123#endif
124/* ========= end header generated by ./mkh ========= */
125
126#ifdef REDEBUG
127#define SP(t, s, c) print(m, t, s, c, stdout)
128#define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
129#define NOTE(str) { if (m->eflags&REG_TRACE) printf("=%s\n", (str)); }
130#else
131#define SP(t, s, c) /* nothing */
132#define AT(t, p1, p2, s1, s2) /* nothing */
133#define NOTE(s) /* nothing */
134#endif
135
136/*
137 - matcher - the actual matching engine
138 == static int matcher(struct re_guts *g, char *string, \
139 == size_t nmatch, regmatch_t pmatch[], int eflags);
140 */
141static int /* 0 success, REG_NOMATCH failure */
142matcher(g, string, nmatch, pmatch, eflags)
143struct re_guts *g;
144char *string;
145size_t nmatch;
146regmatch_t pmatch[];
147int eflags;
148{
149 char *endp;
150 int i;
151 struct match mv;
152 struct match *m = &mv;
153 char *dp;
154 const sopno gf = g->firststate+1; /* +1 for OEND */
155 const sopno gl = g->laststate;
156 char *start;
157 char *stop;
158 /* Boyer-Moore algorithms variables */
159 char *pp;
160 int cj, mj;
161 char *mustfirst;
162 char *mustlast;
163 int *matchjump;
164 int *charjump;
165
166 /* simplify the situation where possible */
167 if (g->cflags&REG_NOSUB)
168 nmatch = 0;
169 if (eflags&REG_STARTEND) {
170 start = string + pmatch[0].rm_so;
171 stop = string + pmatch[0].rm_eo;
172 } else {
173 start = string;
174 stop = start + strlen(start);
175 }
176 if (stop < start)
177 return(REG_INVARG);
178
179 /* prescreening; this does wonders for this rather slow code */
180 if (g->must != NULL) {
181 if (g->charjump != NULL && g->matchjump != NULL) {
182 mustfirst = g->must;
183 mustlast = g->must + g->mlen - 1;
184 charjump = g->charjump;
185 matchjump = g->matchjump;
186 pp = mustlast;
187 for (dp = start+g->mlen-1; dp < stop;) {
188 /* Fast skip non-matches */
189 while (dp < stop && charjump[(int)*dp])
190 dp += charjump[(int)*dp];
191
192 if (dp >= stop)
193 break;
194
195 /* Greedy matcher */
196 /* We depend on not being used for
197 * for strings of length 1
198 */
199 while (*--dp == *--pp && pp != mustfirst);
200
201 if (*dp == *pp)
202 break;
203
204 /* Jump to next possible match */
205 mj = matchjump[pp - mustfirst];
206 cj = charjump[(int)*dp];
207 dp += (cj < mj ? mj : cj);
208 pp = mustlast;
209 }
210 if (pp != mustfirst)
211 return(REG_NOMATCH);
212 } else {
213 for (dp = start; dp < stop; dp++)
214 if (*dp == g->must[0] &&
215 stop - dp >= g->mlen &&
216 memcmp(dp, g->must, (size_t)g->mlen) == 0)
217 break;
218 if (dp == stop) /* we didn't find g->must */
219 return(REG_NOMATCH);
220 }
221 }
222
223 /* match struct setup */
224 m->g = g;
225 m->eflags = eflags;
226 m->pmatch = NULL;
227 m->lastpos = NULL;
228 m->offp = string;
229 m->beginp = start;
230 m->endp = stop;
231 STATESETUP(m, 4);
232 SETUP(m->st);
233 SETUP(m->fresh);
234 SETUP(m->tmp);
235 SETUP(m->empty);
236 CLEAR(m->empty);
237
238 /* Adjust start according to moffset, to speed things up */
239 if (g->moffset > -1)
240 start = ((dp - g->moffset) < start) ? start : dp - g->moffset;
241
242 /* this loop does only one repetition except for backrefs */
243 for (;;) {
244 endp = fast(m, start, stop, gf, gl);
245 if (endp == NULL) { /* a miss */
246 STATETEARDOWN(m);
247 return(REG_NOMATCH);
248 }
249 if (nmatch == 0 && !g->backrefs)
250 break; /* no further info needed */
251
252 /* where? */
253 assert(m->coldp != NULL);
254 for (;;) {
255 NOTE("finding start");
256 endp = slow(m, m->coldp, stop, gf, gl);
257 if (endp != NULL)
258 break;
259 assert(m->coldp < m->endp);
260 m->coldp++;
261 }
262 if (nmatch == 1 && !g->backrefs)
263 break; /* no further info needed */
264
265 /* oh my, he wants the subexpressions... */
266 if (m->pmatch == NULL)
267 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
268 sizeof(regmatch_t));
269 if (m->pmatch == NULL) {
270 STATETEARDOWN(m);
271 return(REG_ESPACE);
272 }
273 for (i = 1; i <= m->g->nsub; i++)
274 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
275 if (!g->backrefs && !(m->eflags&REG_BACKR)) {
276 NOTE("dissecting");
277 dp = dissect(m, m->coldp, endp, gf, gl);
278 } else {
279 if (g->nplus > 0 && m->lastpos == NULL)
280 m->lastpos = (char **)malloc((g->nplus+1) *
281 sizeof(char *));
282 if (g->nplus > 0 && m->lastpos == NULL) {
283 free(m->pmatch);
284 STATETEARDOWN(m);
285 return(REG_ESPACE);
286 }
287 NOTE("backref dissect");
288 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
289 }
290 if (dp != NULL)
291 break;
292
293 /* uh-oh... we couldn't find a subexpression-level match */
294 assert(g->backrefs); /* must be back references doing it */
295 assert(g->nplus == 0 || m->lastpos != NULL);
296 for (;;) {
297 if (dp != NULL || endp <= m->coldp)
298 break; /* defeat */
299 NOTE("backoff");
300 endp = slow(m, m->coldp, endp-1, gf, gl);
301 if (endp == NULL)
302 break; /* defeat */
303 /* try it on a shorter possibility */
304#ifndef NDEBUG
305 for (i = 1; i <= m->g->nsub; i++) {
306 assert(m->pmatch[i].rm_so == -1);
307 assert(m->pmatch[i].rm_eo == -1);
308 }
309#endif
310 NOTE("backoff dissect");
311 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
312 }
313 assert(dp == NULL || dp == endp);
314 if (dp != NULL) /* found a shorter one */
315 break;
316
317 /* despite initial appearances, there is no match here */
318 NOTE("false alarm");
319 start = m->coldp + 1; /* recycle starting later */
320 assert(start <= stop);
321 }
322
323 /* fill in the details if requested */
324 if (nmatch > 0) {
325 pmatch[0].rm_so = m->coldp - m->offp;
326 pmatch[0].rm_eo = endp - m->offp;
327 }
328 if (nmatch > 1) {
329 assert(m->pmatch != NULL);
330 for (i = 1; i < nmatch; i++)
331 if (i <= m->g->nsub)
332 pmatch[i] = m->pmatch[i];
333 else {
334 pmatch[i].rm_so = -1;
335 pmatch[i].rm_eo = -1;
336 }
337 }
338
339 if (m->pmatch != NULL)
340 free((char *)m->pmatch);
341 if (m->lastpos != NULL)
342 free((char *)m->lastpos);
343 STATETEARDOWN(m);
344 return(0);
345}
346
347/*
348 - dissect - figure out what matched what, no back references
349 == static char *dissect(struct match *m, char *start, \
350 == char *stop, sopno startst, sopno stopst);
351 */
352static char * /* == stop (success) always */
353dissect(m, start, stop, startst, stopst)
354struct match *m;
355char *start;
356char *stop;
357sopno startst;
358sopno stopst;
359{
360 int i;
361 sopno ss; /* start sop of current subRE */
362 sopno es; /* end sop of current subRE */
363 char *sp; /* start of string matched by it */
364 char *stp; /* string matched by it cannot pass here */
365 char *rest; /* start of rest of string */
366 char *tail; /* string unmatched by rest of RE */
367 sopno ssub; /* start sop of subsubRE */
368 sopno esub; /* end sop of subsubRE */
369 char *ssp; /* start of string matched by subsubRE */
370 char *sep; /* end of string matched by subsubRE */
371 char *oldssp; /* previous ssp */
372 char *dp;
373
374 AT("diss", start, stop, startst, stopst);
375 sp = start;
376 for (ss = startst; ss < stopst; ss = es) {
377 /* identify end of subRE */
378 es = ss;
379 switch (OP(m->g->strip[es])) {
380 case OPLUS_:
381 case OQUEST_:
382 es += OPND(m->g->strip[es]);
383 break;
384 case OCH_:
385 while (OP(m->g->strip[es]) != O_CH)
386 es += OPND(m->g->strip[es]);
387 break;
388 }
389 es++;
390
391 /* figure out what it matched */
392 switch (OP(m->g->strip[ss])) {
393 case OEND:
394 assert(nope);
395 break;
396 case OCHAR:
397 sp++;
398 break;
399 case OBOL:
400 case OEOL:
401 case OBOW:
402 case OEOW:
403 break;
404 case OANY:
405 case OANYOF:
406 sp++;
407 break;
408 case OBACK_:
409 case O_BACK:
410 assert(nope);
411 break;
412 /* cases where length of match is hard to find */
413 case OQUEST_:
414 stp = stop;
415 for (;;) {
416 /* how long could this one be? */
417 rest = slow(m, sp, stp, ss, es);
418 assert(rest != NULL); /* it did match */
419 /* could the rest match the rest? */
420 tail = slow(m, rest, stop, es, stopst);
421 if (tail == stop)
422 break; /* yes! */
423 /* no -- try a shorter match for this one */
424 stp = rest - 1;
425 assert(stp >= sp); /* it did work */
426 }
427 ssub = ss + 1;
428 esub = es - 1;
429 /* did innards match? */
430 if (slow(m, sp, rest, ssub, esub) != NULL) {
431 dp = dissect(m, sp, rest, ssub, esub);
432 assert(dp == rest);
433 } else /* no */
434 assert(sp == rest);
435 sp = rest;
436 break;
437 case OPLUS_:
438 stp = stop;
439 for (;;) {
440 /* how long could this one be? */
441 rest = slow(m, sp, stp, ss, es);
442 assert(rest != NULL); /* it did match */
443 /* could the rest match the rest? */
444 tail = slow(m, rest, stop, es, stopst);
445 if (tail == stop)
446 break; /* yes! */
447 /* no -- try a shorter match for this one */
448 stp = rest - 1;
449 assert(stp >= sp); /* it did work */
450 }
451 ssub = ss + 1;
452 esub = es - 1;
453 ssp = sp;
454 oldssp = ssp;
455 for (;;) { /* find last match of innards */
456 sep = slow(m, ssp, rest, ssub, esub);
457 if (sep == NULL || sep == ssp)
458 break; /* failed or matched null */
459 oldssp = ssp; /* on to next try */
460 ssp = sep;
461 }
462 if (sep == NULL) {
463 /* last successful match */
464 sep = ssp;
465 ssp = oldssp;
466 }
467 assert(sep == rest); /* must exhaust substring */
468 assert(slow(m, ssp, sep, ssub, esub) == rest);
469 dp = dissect(m, ssp, sep, ssub, esub);
470 assert(dp == sep);
471 sp = rest;
472 break;
473 case OCH_:
474 stp = stop;
475 for (;;) {
476 /* how long could this one be? */
477 rest = slow(m, sp, stp, ss, es);
478 assert(rest != NULL); /* it did match */
479 /* could the rest match the rest? */
480 tail = slow(m, rest, stop, es, stopst);
481 if (tail == stop)
482 break; /* yes! */
483 /* no -- try a shorter match for this one */
484 stp = rest - 1;
485 assert(stp >= sp); /* it did work */
486 }
487 ssub = ss + 1;
488 esub = ss + OPND(m->g->strip[ss]) - 1;
489 assert(OP(m->g->strip[esub]) == OOR1);
490 for (;;) { /* find first matching branch */
491 if (slow(m, sp, rest, ssub, esub) == rest)
492 break; /* it matched all of it */
493 /* that one missed, try next one */
494 assert(OP(m->g->strip[esub]) == OOR1);
495 esub++;
496 assert(OP(m->g->strip[esub]) == OOR2);
497 ssub = esub + 1;
498 esub += OPND(m->g->strip[esub]);
499 if (OP(m->g->strip[esub]) == OOR2)
500 esub--;
501 else
502 assert(OP(m->g->strip[esub]) == O_CH);
503 }
504 dp = dissect(m, sp, rest, ssub, esub);
505 assert(dp == rest);
506 sp = rest;
507 break;
508 case O_PLUS:
509 case O_QUEST:
510 case OOR1:
511 case OOR2:
512 case O_CH:
513 assert(nope);
514 break;
515 case OLPAREN:
516 i = OPND(m->g->strip[ss]);
517 assert(0 < i && i <= m->g->nsub);
518 m->pmatch[i].rm_so = sp - m->offp;
519 break;
520 case ORPAREN:
521 i = OPND(m->g->strip[ss]);
522 assert(0 < i && i <= m->g->nsub);
523 m->pmatch[i].rm_eo = sp - m->offp;
524 break;
525 default: /* uh oh */
526 assert(nope);
527 break;
528 }
529 }
530
531 assert(sp == stop);
532 return(sp);
533}
534
535/*
536 - backref - figure out what matched what, figuring in back references
537 == static char *backref(struct match *m, char *start, \
538 == char *stop, sopno startst, sopno stopst, sopno lev);
539 */
540static char * /* == stop (success) or NULL (failure) */
541backref(m, start, stop, startst, stopst, lev)
542struct match *m;
543char *start;
544char *stop;
545sopno startst;
546sopno stopst;
547sopno lev; /* PLUS nesting level */
548{
549 int i;
550 sopno ss; /* start sop of current subRE */
551 char *sp; /* start of string matched by it */
552 sopno ssub; /* start sop of subsubRE */
553 sopno esub; /* end sop of subsubRE */
554 char *ssp; /* start of string matched by subsubRE */
555 char *dp;
556 size_t len;
557 int hard;
558 sop s;
559 regoff_t offsave;
560 cset *cs;
561
562 AT("back", start, stop, startst, stopst);
563 sp = start;
564
565 /* get as far as we can with easy stuff */
566 hard = 0;
567 for (ss = startst; !hard && ss < stopst; ss++)
568 switch (OP(s = m->g->strip[ss])) {
569 case OCHAR:
570 if (sp == stop || *sp++ != (char)OPND(s))
571 return(NULL);
572 break;
573 case OANY:
574 if (sp == stop)
575 return(NULL);
576 sp++;
577 break;
578 case OANYOF:
579 cs = &m->g->sets[OPND(s)];
580 if (sp == stop || !CHIN(cs, *sp++))
581 return(NULL);
582 break;
583 case OBOL:
584 if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
585 (sp < m->endp && *(sp-1) == '\n' &&
586 (m->g->cflags&REG_NEWLINE)) )
587 { /* yes */ }
588 else
589 return(NULL);
590 break;
591 case OEOL:
592 if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
593 (sp < m->endp && *sp == '\n' &&
594 (m->g->cflags&REG_NEWLINE)) )
595 { /* yes */ }
596 else
597 return(NULL);
598 break;
599 case OBOW:
600 if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
601 (sp < m->endp && *(sp-1) == '\n' &&
602 (m->g->cflags&REG_NEWLINE)) ||
603 (sp > m->beginp &&
604 !ISWORD(*(sp-1))) ) &&
605 (sp < m->endp && ISWORD(*sp)) )
606 { /* yes */ }
607 else
608 return(NULL);
609 break;
610 case OEOW:
611 if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
612 (sp < m->endp && *sp == '\n' &&
613 (m->g->cflags&REG_NEWLINE)) ||
614 (sp < m->endp && !ISWORD(*sp)) ) &&
615 (sp > m->beginp && ISWORD(*(sp-1))) )
616 { /* yes */ }
617 else
618 return(NULL);
619 break;
620 case O_QUEST:
621 break;
622 case OOR1: /* matches null but needs to skip */
623 ss++;
624 s = m->g->strip[ss];
625 do {
626 assert(OP(s) == OOR2);
627 ss += OPND(s);
628 } while (OP(s = m->g->strip[ss]) != O_CH);
629 /* note that the ss++ gets us past the O_CH */
630 break;
631 default: /* have to make a choice */
632 hard = 1;
633 break;
634 }
635 if (!hard) { /* that was it! */
636 if (sp != stop)
637 return(NULL);
638 return(sp);
639 }
640 ss--; /* adjust for the for's final increment */
641
642 /* the hard stuff */
643 AT("hard", sp, stop, ss, stopst);
644 s = m->g->strip[ss];
645 switch (OP(s)) {
646 case OBACK_: /* the vilest depths */
647 i = OPND(s);
648 assert(0 < i && i <= m->g->nsub);
649 if (m->pmatch[i].rm_eo == -1)
650 return(NULL);
651 assert(m->pmatch[i].rm_so != -1);
652 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
653 assert(stop - m->beginp >= len);
654 if (sp > stop - len)
655 return(NULL); /* not enough left to match */
656 ssp = m->offp + m->pmatch[i].rm_so;
657 if (memcmp(sp, ssp, len) != 0)
658 return(NULL);
659 while (m->g->strip[ss] != SOP(O_BACK, i))
660 ss++;
661 return(backref(m, sp+len, stop, ss+1, stopst, lev));
662 break;
663 case OQUEST_: /* to null or not */
664 dp = backref(m, sp, stop, ss+1, stopst, lev);
665 if (dp != NULL)
666 return(dp); /* not */
667 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev));
668 break;
669 case OPLUS_:
670 assert(m->lastpos != NULL);
671 assert(lev+1 <= m->g->nplus);
672 m->lastpos[lev+1] = sp;
673 return(backref(m, sp, stop, ss+1, stopst, lev+1));
674 break;
675 case O_PLUS:
676 if (sp == m->lastpos[lev]) /* last pass matched null */
677 return(backref(m, sp, stop, ss+1, stopst, lev-1));
678 /* try another pass */
679 m->lastpos[lev] = sp;
680 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev);
681 if (dp == NULL)
682 return(backref(m, sp, stop, ss+1, stopst, lev-1));
683 else
684 return(dp);
685 break;
686 case OCH_: /* find the right one, if any */
687 ssub = ss + 1;
688 esub = ss + OPND(s) - 1;
689 assert(OP(m->g->strip[esub]) == OOR1);
690 for (;;) { /* find first matching branch */
691 dp = backref(m, sp, stop, ssub, esub, lev);
692 if (dp != NULL)
693 return(dp);
694 /* that one missed, try next one */
695 if (OP(m->g->strip[esub]) == O_CH)
696 return(NULL); /* there is none */
697 esub++;
698 assert(OP(m->g->strip[esub]) == OOR2);
699 ssub = esub + 1;
700 esub += OPND(m->g->strip[esub]);
701 if (OP(m->g->strip[esub]) == OOR2)
702 esub--;
703 else
704 assert(OP(m->g->strip[esub]) == O_CH);
705 }
706 break;
707 case OLPAREN: /* must undo assignment if rest fails */
708 i = OPND(s);
709 assert(0 < i && i <= m->g->nsub);
710 offsave = m->pmatch[i].rm_so;
711 m->pmatch[i].rm_so = sp - m->offp;
712 dp = backref(m, sp, stop, ss+1, stopst, lev);
713 if (dp != NULL)
714 return(dp);
715 m->pmatch[i].rm_so = offsave;
716 return(NULL);
717 break;
718 case ORPAREN: /* must undo assignment if rest fails */
719 i = OPND(s);
720 assert(0 < i && i <= m->g->nsub);
721 offsave = m->pmatch[i].rm_eo;
722 m->pmatch[i].rm_eo = sp - m->offp;
723 dp = backref(m, sp, stop, ss+1, stopst, lev);
724 if (dp != NULL)
725 return(dp);
726 m->pmatch[i].rm_eo = offsave;
727 return(NULL);
728 break;
729 default: /* uh oh */
730 assert(nope);
731 break;
732 }
733
734 /* "can't happen" */
735 assert(nope);
736 /* NOTREACHED */
737 return "shut up gcc";
738}
739
740/*
741 - fast - step through the string at top speed
742 == static char *fast(struct match *m, char *start, \
743 == char *stop, sopno startst, sopno stopst);
744 */
745static char * /* where tentative match ended, or NULL */
746fast(m, start, stop, startst, stopst)
747struct match *m;
748char *start;
749char *stop;
750sopno startst;
751sopno stopst;
752{
753 states st = m->st;
754 states fresh = m->fresh;
755 states tmp = m->tmp;
756 char *p = start;
757 int c = (start == m->beginp) ? OUT : *(start-1);
758 int lastc; /* previous c */
759 int flagch;
760 int i;
761 char *coldp; /* last p after which no match was underway */
762
763 CLEAR(st);
764 SET1(st, startst);
765 st = step(m->g, startst, stopst, st, NOTHING, st);
766 ASSIGN(fresh, st);
767 SP("start", st, *p);
768 coldp = NULL;
769 for (;;) {
770 /* next character */
771 lastc = c;
772 c = (p == m->endp) ? OUT : *p;
773 if (EQ(st, fresh))
774 coldp = p;
775
776 /* is there an EOL and/or BOL between lastc and c? */
777 flagch = '\0';
778 i = 0;
779 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
780 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
781 flagch = BOL;
782 i = m->g->nbol;
783 }
784 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
785 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
786 flagch = (flagch == BOL) ? BOLEOL : EOL;
787 i += m->g->neol;
788 }
789 if (i != 0) {
790 for (; i > 0; i--)
791 st = step(m->g, startst, stopst, st, flagch, st);
792 SP("boleol", st, c);
793 }
794
795 /* how about a word boundary? */
796 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
797 (c != OUT && ISWORD(c)) ) {
798 flagch = BOW;
799 }
800 if ( (lastc != OUT && ISWORD(lastc)) &&
801 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
802 flagch = EOW;
803 }
804 if (flagch == BOW || flagch == EOW) {
805 st = step(m->g, startst, stopst, st, flagch, st);
806 SP("boweow", st, c);
807 }
808
809 /* are we done? */
810 if (ISSET(st, stopst) || p == stop)
811 break; /* NOTE BREAK OUT */
812
813 /* no, we must deal with this character */
814 ASSIGN(tmp, st);
815 ASSIGN(st, fresh);
816 assert(c != OUT);
817 st = step(m->g, startst, stopst, tmp, c, st);
818 SP("aft", st, c);
819 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
820 p++;
821 }
822
823 assert(coldp != NULL);
824 m->coldp = coldp;
825 if (ISSET(st, stopst))
826 return(p+1);
827 else
828 return(NULL);
829}
830
831/*
832 - slow - step through the string more deliberately
833 == static char *slow(struct match *m, char *start, \
834 == char *stop, sopno startst, sopno stopst);
835 */
836static char * /* where it ended */
837slow(m, start, stop, startst, stopst)
838struct match *m;
839char *start;
840char *stop;
841sopno startst;
842sopno stopst;
843{
844 states st = m->st;
845 states empty = m->empty;
846 states tmp = m->tmp;
847 char *p = start;
848 int c = (start == m->beginp) ? OUT : *(start-1);
849 int lastc; /* previous c */
850 int flagch;
851 int i;
852 char *matchp; /* last p at which a match ended */
853
854 AT("slow", start, stop, startst, stopst);
855 CLEAR(st);
856 SET1(st, startst);
857 SP("sstart", st, *p);
858 st = step(m->g, startst, stopst, st, NOTHING, st);
859 matchp = NULL;
860 for (;;) {
861 /* next character */
862 lastc = c;
863 c = (p == m->endp) ? OUT : *p;
864
865 /* is there an EOL and/or BOL between lastc and c? */
866 flagch = '\0';
867 i = 0;
868 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
869 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
870 flagch = BOL;
871 i = m->g->nbol;
872 }
873 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
874 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
875 flagch = (flagch == BOL) ? BOLEOL : EOL;
876 i += m->g->neol;
877 }
878 if (i != 0) {
879 for (; i > 0; i--)
880 st = step(m->g, startst, stopst, st, flagch, st);
881 SP("sboleol", st, c);
882 }
883
884 /* how about a word boundary? */
885 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
886 (c != OUT && ISWORD(c)) ) {
887 flagch = BOW;
888 }
889 if ( (lastc != OUT && ISWORD(lastc)) &&
890 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
891 flagch = EOW;
892 }
893 if (flagch == BOW || flagch == EOW) {
894 st = step(m->g, startst, stopst, st, flagch, st);
895 SP("sboweow", st, c);
896 }
897
898 /* are we done? */
899 if (ISSET(st, stopst))
900 matchp = p;
901 if (EQ(st, empty) || p == stop)
902 break; /* NOTE BREAK OUT */
903
904 /* no, we must deal with this character */
905 ASSIGN(tmp, st);
906 ASSIGN(st, empty);
907 assert(c != OUT);
908 st = step(m->g, startst, stopst, tmp, c, st);
909 SP("saft", st, c);
910 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
911 p++;
912 }
913
914 return(matchp);
915}
916
917
918/*
919 - step - map set of states reachable before char to set reachable after
920 == static states step(struct re_guts *g, sopno start, sopno stop, \
921 == states bef, int ch, states aft);
922 == #define BOL (OUT+1)
923 == #define EOL (BOL+1)
924 == #define BOLEOL (BOL+2)
925 == #define NOTHING (BOL+3)
926 == #define BOW (BOL+4)
927 == #define EOW (BOL+5)
928 == #define CODEMAX (BOL+5) // highest code used
929 == #define NONCHAR(c) ((c) > CHAR_MAX)
930 == #define NNONCHAR (CODEMAX-CHAR_MAX)
931 */
932static states
933step(g, start, stop, bef, ch, aft)
934struct re_guts *g;
935sopno start; /* start state within strip */
936sopno stop; /* state after stop state within strip */
937states bef; /* states reachable before */
938int ch; /* character or NONCHAR code */
939states aft; /* states already known reachable after */
940{
941 cset *cs;
942 sop s;
943 sopno pc;
944 onestate here; /* note, macros know this name */
945 sopno look;
946 int i;
947
948 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
949 s = g->strip[pc];
950 switch (OP(s)) {
951 case OEND:
952 assert(pc == stop-1);
953 break;
954 case OCHAR:
955 /* only characters can match */
956 assert(!NONCHAR(ch) || ch != (char)OPND(s));
957 if (ch == (char)OPND(s))
958 FWD(aft, bef, 1);
959 break;
960 case OBOL:
961 if (ch == BOL || ch == BOLEOL)
962 FWD(aft, bef, 1);
963 break;
964 case OEOL:
965 if (ch == EOL || ch == BOLEOL)
966 FWD(aft, bef, 1);
967 break;
968 case OBOW:
969 if (ch == BOW)
970 FWD(aft, bef, 1);
971 break;
972 case OEOW:
973 if (ch == EOW)
974 FWD(aft, bef, 1);
975 break;
976 case OANY:
977 if (!NONCHAR(ch))
978 FWD(aft, bef, 1);
979 break;
980 case OANYOF:
981 cs = &g->sets[OPND(s)];
982 if (!NONCHAR(ch) && CHIN(cs, ch))
983 FWD(aft, bef, 1);
984 break;
985 case OBACK_: /* ignored here */
986 case O_BACK:
987 FWD(aft, aft, 1);
988 break;
989 case OPLUS_: /* forward, this is just an empty */
990 FWD(aft, aft, 1);
991 break;
992 case O_PLUS: /* both forward and back */
993 FWD(aft, aft, 1);
994 i = ISSETBACK(aft, OPND(s));
995 BACK(aft, aft, OPND(s));
996 if (!i && ISSETBACK(aft, OPND(s))) {
997 /* oho, must reconsider loop body */
998 pc -= OPND(s) + 1;
999 INIT(here, pc);
1000 }
1001 break;
1002 case OQUEST_: /* two branches, both forward */
1003 FWD(aft, aft, 1);
1004 FWD(aft, aft, OPND(s));
1005 break;
1006 case O_QUEST: /* just an empty */
1007 FWD(aft, aft, 1);
1008 break;
1009 case OLPAREN: /* not significant here */
1010 case ORPAREN:
1011 FWD(aft, aft, 1);
1012 break;
1013 case OCH_: /* mark the first two branches */
1014 FWD(aft, aft, 1);
1015 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1016 FWD(aft, aft, OPND(s));
1017 break;
1018 case OOR1: /* done a branch, find the O_CH */
1019 if (ISSTATEIN(aft, here)) {
1020 for (look = 1;
1021 OP(s = g->strip[pc+look]) != O_CH;
1022 look += OPND(s))
1023 assert(OP(s) == OOR2);
1024 FWD(aft, aft, look);
1025 }
1026 break;
1027 case OOR2: /* propagate OCH_'s marking */
1028 FWD(aft, aft, 1);
1029 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
1030 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1031 FWD(aft, aft, OPND(s));
1032 }
1033 break;
1034 case O_CH: /* just empty */
1035 FWD(aft, aft, 1);
1036 break;
1037 default: /* ooooops... */
1038 assert(nope);
1039 break;
1040 }
1041 }
1042
1043 return(aft);
1044}
1045
1046#ifdef REDEBUG
1047/*
1048 - print - print a set of states
1049 == #ifdef REDEBUG
1050 == static void print(struct match *m, char *caption, states st, \
1051 == int ch, FILE *d);
1052 == #endif
1053 */
1054static void
1055print(m, caption, st, ch, d)
1056struct match *m;
1057char *caption;
1058states st;
1059int ch;
1060FILE *d;
1061{
1062 struct re_guts *g = m->g;
1063 int i;
1064 int first = 1;
1065
1066 if (!(m->eflags&REG_TRACE))
1067 return;
1068
1069 fprintf(d, "%s", caption);
1070 if (ch != '\0')
1071 fprintf(d, " %s", pchar(ch));
1072 for (i = 0; i < g->nstates; i++)
1073 if (ISSET(st, i)) {
1074 fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
1075 first = 0;
1076 }
1077 fprintf(d, "\n");
1078}
1079
1080/*
1081 - at - print current situation
1082 == #ifdef REDEBUG
1083 == static void at(struct match *m, char *title, char *start, char *stop, \
1084 == sopno startst, sopno stopst);
1085 == #endif
1086 */
1087static void
1088at(m, title, start, stop, startst, stopst)
1089struct match *m;
1090char *title;
1091char *start;
1092char *stop;
1093sopno startst;
1094sopno stopst;
1095{
1096 if (!(m->eflags&REG_TRACE))
1097 return;
1098
1099 printf("%s %s-", title, pchar(*start));
1100 printf("%s ", pchar(*stop));
1101 printf("%ld-%ld\n", (long)startst, (long)stopst);
1102}
1103
1104#ifndef PCHARDONE
1105#define PCHARDONE /* never again */
1106/*
1107 - pchar - make a character printable
1108 == #ifdef REDEBUG
1109 == static char *pchar(int ch);
1110 == #endif
1111 *
1112 * Is this identical to regchar() over in debug.c? Well, yes. But a
1113 * duplicate here avoids having a debugging-capable regexec.o tied to
1114 * a matching debug.o, and this is convenient. It all disappears in
1115 * the non-debug compilation anyway, so it doesn't matter much.
1116 */
1117static char * /* -> representation */
1118pchar(ch)
1119int ch;
1120{
1121 static char pbuf[10];
1122
1123 if (isprint((uch)ch) || ch == ' ')
1124 sprintf(pbuf, "%c", ch);
1125 else
1126 sprintf(pbuf, "\\%o", ch);
1127 return(pbuf);
1128}
1129#endif
1130#endif
1131
1132#undef matcher
1133#undef fast
1134#undef slow
1135#undef dissect
1136#undef backref
1137#undef step
1138#undef print
1139#undef at
1140#undef match
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