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Really fix indent.
[dragonfly.git] / lib / libc / regex / engine.c
bloba92832db810358a803c803e2a0610813f0a4f3de
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 * $FreeBSD: src/lib/libc/regex/engine.c,v 1.5.8.1 2000/07/31 06:30:37 dcs Exp $
40 * $DragonFly: src/lib/libc/regex/engine.c,v 1.7 2005/11/20 09:18:37 swildner Exp $
41 */
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 */
74 struct 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
92 extern "C" {
93 #endif
94
95 /* === engine.c === */
96 static int matcher(struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags);
97 static char *dissect(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
98 static char *backref(struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev);
99 static char *fast(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
100 static char *slow(struct match *m, char *start, char *stop, sopno startst, sopno stopst);
101 static 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
112 static void print(struct match *m, char *caption, states st, int ch, FILE *d);
113 #endif
114 #ifdef REDEBUG
115 static void at(struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst);
116 #endif
117 #ifdef REDEBUG
118 static 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 */
141 static int /* 0 success, REG_NOMATCH failure */
142 matcher(struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[],
143 int eflags)
144 {
145 char *endp;
146 int i;
147 struct match mv;
148 struct match *m = &mv;
149 char *dp;
150 const sopno gf = g->firststate+1; /* +1 for OEND */
151 const sopno gl = g->laststate;
152 char *start;
153 char *stop;
154 /* Boyer-Moore algorithms variables */
155 char *pp;
156 int cj, mj;
157 char *mustfirst;
158 char *mustlast;
159 int *matchjump;
160 int *charjump;
161
162 dp = NULL;
163
164 /* simplify the situation where possible */
165 if (g->cflags&REG_NOSUB)
166 nmatch = 0;
167 if (eflags&REG_STARTEND) {
168 start = string + pmatch[0].rm_so;
169 stop = string + pmatch[0].rm_eo;
170 } else {
171 start = string;
172 stop = start + strlen(start);
173 }
174 if (stop < start)
175 return(REG_INVARG);
176
177 /* prescreening; this does wonders for this rather slow code */
178 if (g->must != NULL) {
179 if (g->charjump != NULL && g->matchjump != NULL) {
180 mustfirst = g->must;
181 mustlast = g->must + g->mlen - 1;
182 charjump = g->charjump;
183 matchjump = g->matchjump;
184 pp = mustlast;
185 for (dp = start+g->mlen-1; dp < stop;) {
186 /* Fast skip non-matches */
187 while (dp < stop && charjump[*dp])
188 dp += charjump[*dp];
189
190 if (dp >= stop)
191 break;
192
193 /* Greedy matcher */
194 /* We depend on not being used for
195 * for strings of length 1
196 */
197 while (*--dp == *--pp && pp != mustfirst);
198
199 if (*dp == *pp)
200 break;
201
202 /* Jump to next possible match */
203 mj = matchjump[pp - mustfirst];
204 cj = charjump[*dp];
205 dp += (cj < mj ? mj : cj);
206 pp = mustlast;
207 }
208 if (pp != mustfirst)
209 return(REG_NOMATCH);
210 } else {
211 for (dp = start; dp < stop; dp++)
212 if (*dp == g->must[0] &&
213 stop - dp >= g->mlen &&
214 memcmp(dp, g->must, (size_t)g->mlen) == 0)
215 break;
216 if (dp == stop) /* we didn't find g->must */
217 return(REG_NOMATCH);
218 }
219 }
220
221 /* match struct setup */
222 m->g = g;
223 m->eflags = eflags;
224 m->pmatch = NULL;
225 m->lastpos = NULL;
226 m->offp = string;
227 m->beginp = start;
228 m->endp = stop;
229 STATESETUP(m, 4);
230 SETUP(m->st);
231 SETUP(m->fresh);
232 SETUP(m->tmp);
233 SETUP(m->empty);
234 CLEAR(m->empty);
235
236 /* Adjust start according to moffset, to speed things up */
237 if (g->moffset > -1)
238 start = ((dp - g->moffset) < start) ? start : dp - g->moffset;
239
240 /* this loop does only one repetition except for backrefs */
241 for (;;) {
242 endp = fast(m, start, stop, gf, gl);
243 if (endp == NULL) { /* a miss */
244 if (m->pmatch != NULL)
245 free((char *)m->pmatch);
246 if (m->lastpos != NULL)
247 free((char *)m->lastpos);
248 STATETEARDOWN(m);
249 return(REG_NOMATCH);
250 }
251 if (nmatch == 0 && !g->backrefs)
252 break; /* no further info needed */
253
254 /* where? */
255 assert(m->coldp != NULL);
256 for (;;) {
257 NOTE("finding start");
258 endp = slow(m, m->coldp, stop, gf, gl);
259 if (endp != NULL)
260 break;
261 assert(m->coldp < m->endp);
262 m->coldp++;
263 }
264 if (nmatch == 1 && !g->backrefs)
265 break; /* no further info needed */
266
267 /* oh my, he wants the subexpressions... */
268 if (m->pmatch == NULL)
269 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
270 sizeof(regmatch_t));
271 if (m->pmatch == NULL) {
272 STATETEARDOWN(m);
273 return(REG_ESPACE);
274 }
275 for (i = 1; i <= m->g->nsub; i++)
276 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
277 if (!g->backrefs && !(m->eflags&REG_BACKR)) {
278 NOTE("dissecting");
279 dp = dissect(m, m->coldp, endp, gf, gl);
280 } else {
281 if (g->nplus > 0 && m->lastpos == NULL)
282 m->lastpos = (char **)malloc((g->nplus+1) *
283 sizeof(char *));
284 if (g->nplus > 0 && m->lastpos == NULL) {
285 free(m->pmatch);
286 STATETEARDOWN(m);
287 return(REG_ESPACE);
288 }
289 NOTE("backref dissect");
290 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
291 }
292 if (dp != NULL)
293 break;
294
295 /* uh-oh... we couldn't find a subexpression-level match */
296 assert(g->backrefs); /* must be back references doing it */
297 assert(g->nplus == 0 || m->lastpos != NULL);
298 for (;;) {
299 if (dp != NULL || endp <= m->coldp)
300 break; /* defeat */
301 NOTE("backoff");
302 endp = slow(m, m->coldp, endp-1, gf, gl);
303 if (endp == NULL)
304 break; /* defeat */
305 /* try it on a shorter possibility */
306 #ifndef NDEBUG
307 for (i = 1; i <= m->g->nsub; i++) {
308 assert(m->pmatch[i].rm_so == -1);
309 assert(m->pmatch[i].rm_eo == -1);
310 }
311 #endif
312 NOTE("backoff dissect");
313 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
314 }
315 assert(dp == NULL || dp == endp);
316 if (dp != NULL) /* found a shorter one */
317 break;
318
319 /* despite initial appearances, there is no match here */
320 NOTE("false alarm");
321 start = m->coldp + 1; /* recycle starting later */
322 assert(start <= stop);
323 }
324
325 /* fill in the details if requested */
326 if (nmatch > 0) {
327 pmatch[0].rm_so = m->coldp - m->offp;
328 pmatch[0].rm_eo = endp - m->offp;
329 }
330 if (nmatch > 1) {
331 assert(m->pmatch != NULL);
332 for (i = 1; i < nmatch; i++)
333 if (i <= m->g->nsub)
334 pmatch[i] = m->pmatch[i];
335 else {
336 pmatch[i].rm_so = -1;
337 pmatch[i].rm_eo = -1;
338 }
339 }
340
341 if (m->pmatch != NULL)
342 free((char *)m->pmatch);
343 if (m->lastpos != NULL)
344 free((char *)m->lastpos);
345 STATETEARDOWN(m);
346 return(0);
347 }
348
349 /*
350 - dissect - figure out what matched what, no back references
351 == static char *dissect(struct match *m, char *start, \
352 == char *stop, sopno startst, sopno stopst);
353 */
354 static char * /* == stop (success) always */
355 dissect(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
356 {
357 int i;
358 sopno ss; /* start sop of current subRE */
359 sopno es; /* end sop of current subRE */
360 char *sp; /* start of string matched by it */
361 char *stp; /* string matched by it cannot pass here */
362 char *rest; /* start of rest of string */
363 char *tail; /* string unmatched by rest of RE */
364 sopno ssub; /* start sop of subsubRE */
365 sopno esub; /* end sop of subsubRE */
366 char *ssp; /* start of string matched by subsubRE */
367 char *sep; /* end of string matched by subsubRE */
368 char *oldssp; /* previous ssp */
369 char *dp;
370
371 AT("diss", start, stop, startst, stopst);
372 sp = start;
373 for (ss = startst; ss < stopst; ss = es) {
374 /* identify end of subRE */
375 es = ss;
376 switch (OP(m->g->strip[es])) {
377 case OPLUS_:
378 case OQUEST_:
379 es += OPND(m->g->strip[es]);
380 break;
381 case OCH_:
382 while (OP(m->g->strip[es]) != O_CH)
383 es += OPND(m->g->strip[es]);
384 break;
385 }
386 es++;
387
388 /* figure out what it matched */
389 switch (OP(m->g->strip[ss])) {
390 case OEND:
391 assert(nope);
392 break;
393 case OCHAR:
394 sp++;
395 break;
396 case OBOL:
397 case OEOL:
398 case OBOW:
399 case OEOW:
400 break;
401 case OANY:
402 case OANYOF:
403 sp++;
404 break;
405 case OBACK_:
406 case O_BACK:
407 assert(nope);
408 break;
409 /* cases where length of match is hard to find */
410 case OQUEST_:
411 stp = stop;
412 for (;;) {
413 /* how long could this one be? */
414 rest = slow(m, sp, stp, ss, es);
415 assert(rest != NULL); /* it did match */
416 /* could the rest match the rest? */
417 tail = slow(m, rest, stop, es, stopst);
418 if (tail == stop)
419 break; /* yes! */
420 /* no -- try a shorter match for this one */
421 stp = rest - 1;
422 assert(stp >= sp); /* it did work */
423 }
424 ssub = ss + 1;
425 esub = es - 1;
426 /* did innards match? */
427 if (slow(m, sp, rest, ssub, esub) != NULL) {
428 dp = dissect(m, sp, rest, ssub, esub);
429 assert(dp == rest);
430 } else /* no */
431 assert(sp == rest);
432 sp = rest;
433 break;
434 case OPLUS_:
435 stp = stop;
436 for (;;) {
437 /* how long could this one be? */
438 rest = slow(m, sp, stp, ss, es);
439 assert(rest != NULL); /* it did match */
440 /* could the rest match the rest? */
441 tail = slow(m, rest, stop, es, stopst);
442 if (tail == stop)
443 break; /* yes! */
444 /* no -- try a shorter match for this one */
445 stp = rest - 1;
446 assert(stp >= sp); /* it did work */
447 }
448 ssub = ss + 1;
449 esub = es - 1;
450 ssp = sp;
451 oldssp = ssp;
452 for (;;) { /* find last match of innards */
453 sep = slow(m, ssp, rest, ssub, esub);
454 if (sep == NULL || sep == ssp)
455 break; /* failed or matched null */
456 oldssp = ssp; /* on to next try */
457 ssp = sep;
458 }
459 if (sep == NULL) {
460 /* last successful match */
461 sep = ssp;
462 ssp = oldssp;
463 }
464 assert(sep == rest); /* must exhaust substring */
465 assert(slow(m, ssp, sep, ssub, esub) == rest);
466 dp = dissect(m, ssp, sep, ssub, esub);
467 assert(dp == sep);
468 sp = rest;
469 break;
470 case OCH_:
471 stp = stop;
472 for (;;) {
473 /* how long could this one be? */
474 rest = slow(m, sp, stp, ss, es);
475 assert(rest != NULL); /* it did match */
476 /* could the rest match the rest? */
477 tail = slow(m, rest, stop, es, stopst);
478 if (tail == stop)
479 break; /* yes! */
480 /* no -- try a shorter match for this one */
481 stp = rest - 1;
482 assert(stp >= sp); /* it did work */
483 }
484 ssub = ss + 1;
485 esub = ss + OPND(m->g->strip[ss]) - 1;
486 assert(OP(m->g->strip[esub]) == OOR1);
487 for (;;) { /* find first matching branch */
488 if (slow(m, sp, rest, ssub, esub) == rest)
489 break; /* it matched all of it */
490 /* that one missed, try next one */
491 assert(OP(m->g->strip[esub]) == OOR1);
492 esub++;
493 assert(OP(m->g->strip[esub]) == OOR2);
494 ssub = esub + 1;
495 esub += OPND(m->g->strip[esub]);
496 if (OP(m->g->strip[esub]) == OOR2)
497 esub--;
498 else
499 assert(OP(m->g->strip[esub]) == O_CH);
500 }
501 dp = dissect(m, sp, rest, ssub, esub);
502 assert(dp == rest);
503 sp = rest;
504 break;
505 case O_PLUS:
506 case O_QUEST:
507 case OOR1:
508 case OOR2:
509 case O_CH:
510 assert(nope);
511 break;
512 case OLPAREN:
513 i = OPND(m->g->strip[ss]);
514 assert(0 < i && i <= m->g->nsub);
515 m->pmatch[i].rm_so = sp - m->offp;
516 break;
517 case ORPAREN:
518 i = OPND(m->g->strip[ss]);
519 assert(0 < i && i <= m->g->nsub);
520 m->pmatch[i].rm_eo = sp - m->offp;
521 break;
522 default: /* uh oh */
523 assert(nope);
524 break;
525 }
526 }
527
528 assert(sp == stop);
529 return(sp);
530 }
531
532 /*
533 - backref - figure out what matched what, figuring in back references
534 == static char *backref(struct match *m, char *start, \
535 == char *stop, sopno startst, sopno stopst, sopno lev);
536 */
537 static char * /* == stop (success) or NULL (failure) */
538 backref(struct match *m, char *start, char *stop, sopno startst, sopno stopst,
539 sopno lev) /* PLUS nesting level */
540 {
541 int i;
542 sopno ss; /* start sop of current subRE */
543 char *sp; /* start of string matched by it */
544 sopno ssub; /* start sop of subsubRE */
545 sopno esub; /* end sop of subsubRE */
546 char *ssp; /* start of string matched by subsubRE */
547 char *dp;
548 size_t len;
549 int hard;
550 sop s;
551 regoff_t offsave;
552 cset *cs;
553
554 AT("back", start, stop, startst, stopst);
555 sp = start;
556
557 /* get as far as we can with easy stuff */
558 hard = 0;
559 for (ss = startst; !hard && ss < stopst; ss++)
560 switch (OP(s = m->g->strip[ss])) {
561 case OCHAR:
562 if (sp == stop || *sp++ != (char)OPND(s))
563 return(NULL);
564 break;
565 case OANY:
566 if (sp == stop)
567 return(NULL);
568 sp++;
569 break;
570 case OANYOF:
571 cs = &m->g->sets[OPND(s)];
572 if (sp == stop || !CHIN(cs, *sp++))
573 return(NULL);
574 break;
575 case OBOL:
576 if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
577 (sp < m->endp && *(sp-1) == '\n' &&
578 (m->g->cflags&REG_NEWLINE)) )
579 { /* yes */ }
580 else
581 return(NULL);
582 break;
583 case OEOL:
584 if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
585 (sp < m->endp && *sp == '\n' &&
586 (m->g->cflags&REG_NEWLINE)) )
587 { /* yes */ }
588 else
589 return(NULL);
590 break;
591 case OBOW:
592 if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
593 (sp < m->endp && *(sp-1) == '\n' &&
594 (m->g->cflags&REG_NEWLINE)) ||
595 (sp > m->beginp &&
596 !ISWORD(*(sp-1))) ) &&
597 (sp < m->endp && ISWORD(*sp)) )
598 { /* yes */ }
599 else
600 return(NULL);
601 break;
602 case OEOW:
603 if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
604 (sp < m->endp && *sp == '\n' &&
605 (m->g->cflags&REG_NEWLINE)) ||
606 (sp < m->endp && !ISWORD(*sp)) ) &&
607 (sp > m->beginp && ISWORD(*(sp-1))) )
608 { /* yes */ }
609 else
610 return(NULL);
611 break;
612 case O_QUEST:
613 break;
614 case OOR1: /* matches null but needs to skip */
615 ss++;
616 s = m->g->strip[ss];
617 do {
618 assert(OP(s) == OOR2);
619 ss += OPND(s);
620 } while (OP(s = m->g->strip[ss]) != O_CH);
621 /* note that the ss++ gets us past the O_CH */
622 break;
623 default: /* have to make a choice */
624 hard = 1;
625 break;
626 }
627 if (!hard) { /* that was it! */
628 if (sp != stop)
629 return(NULL);
630 return(sp);
631 }
632 ss--; /* adjust for the for's final increment */
633
634 /* the hard stuff */
635 AT("hard", sp, stop, ss, stopst);
636 s = m->g->strip[ss];
637 switch (OP(s)) {
638 case OBACK_: /* the vilest depths */
639 i = OPND(s);
640 assert(0 < i && i <= m->g->nsub);
641 if (m->pmatch[i].rm_eo == -1)
642 return(NULL);
643 assert(m->pmatch[i].rm_so != -1);
644 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
645 assert(stop - m->beginp >= len);
646 if (sp > stop - len)
647 return(NULL); /* not enough left to match */
648 ssp = m->offp + m->pmatch[i].rm_so;
649 if (memcmp(sp, ssp, len) != 0)
650 return(NULL);
651 while (m->g->strip[ss] != SOP(O_BACK, i))
652 ss++;
653 return(backref(m, sp+len, stop, ss+1, stopst, lev));
654 break;
655 case OQUEST_: /* to null or not */
656 dp = backref(m, sp, stop, ss+1, stopst, lev);
657 if (dp != NULL)
658 return(dp); /* not */
659 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev));
660 break;
661 case OPLUS_:
662 assert(m->lastpos != NULL);
663 assert(lev+1 <= m->g->nplus);
664 m->lastpos[lev+1] = sp;
665 return(backref(m, sp, stop, ss+1, stopst, lev+1));
666 break;
667 case O_PLUS:
668 if (sp == m->lastpos[lev]) /* last pass matched null */
669 return(backref(m, sp, stop, ss+1, stopst, lev-1));
670 /* try another pass */
671 m->lastpos[lev] = sp;
672 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev);
673 if (dp == NULL)
674 return(backref(m, sp, stop, ss+1, stopst, lev-1));
675 else
676 return(dp);
677 break;
678 case OCH_: /* find the right one, if any */
679 ssub = ss + 1;
680 esub = ss + OPND(s) - 1;
681 assert(OP(m->g->strip[esub]) == OOR1);
682 for (;;) { /* find first matching branch */
683 dp = backref(m, sp, stop, ssub, esub, lev);
684 if (dp != NULL)
685 return(dp);
686 /* that one missed, try next one */
687 if (OP(m->g->strip[esub]) == O_CH)
688 return(NULL); /* there is none */
689 esub++;
690 assert(OP(m->g->strip[esub]) == OOR2);
691 ssub = esub + 1;
692 esub += OPND(m->g->strip[esub]);
693 if (OP(m->g->strip[esub]) == OOR2)
694 esub--;
695 else
696 assert(OP(m->g->strip[esub]) == O_CH);
697 }
698 break;
699 case OLPAREN: /* must undo assignment if rest fails */
700 i = OPND(s);
701 assert(0 < i && i <= m->g->nsub);
702 offsave = m->pmatch[i].rm_so;
703 m->pmatch[i].rm_so = sp - m->offp;
704 dp = backref(m, sp, stop, ss+1, stopst, lev);
705 if (dp != NULL)
706 return(dp);
707 m->pmatch[i].rm_so = offsave;
708 return(NULL);
709 break;
710 case ORPAREN: /* must undo assignment if rest fails */
711 i = OPND(s);
712 assert(0 < i && i <= m->g->nsub);
713 offsave = m->pmatch[i].rm_eo;
714 m->pmatch[i].rm_eo = sp - m->offp;
715 dp = backref(m, sp, stop, ss+1, stopst, lev);
716 if (dp != NULL)
717 return(dp);
718 m->pmatch[i].rm_eo = offsave;
719 return(NULL);
720 break;
721 default: /* uh oh */
722 assert(nope);
723 break;
724 }
725
726 /* "can't happen" */
727 assert(nope);
728 /* NOTREACHED */
729 return "shut up gcc";
730 }
731
732 /*
733 - fast - step through the string at top speed
734 == static char *fast(struct match *m, char *start, \
735 == char *stop, sopno startst, sopno stopst);
736 */
737 static char * /* where tentative match ended, or NULL */
738 fast(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
739 {
740 states st = m->st;
741 states fresh = m->fresh;
742 states tmp = m->tmp;
743 char *p = start;
744 int c = (start == m->beginp) ? OUT : *(start-1);
745 int lastc; /* previous c */
746 int flagch;
747 int i;
748 char *coldp; /* last p after which no match was underway */
749
750 CLEAR(st);
751 SET1(st, startst);
752 st = step(m->g, startst, stopst, st, NOTHING, st);
753 ASSIGN(fresh, st);
754 SP("start", st, *p);
755 coldp = NULL;
756 for (;;) {
757 /* next character */
758 lastc = c;
759 c = (p == m->endp) ? OUT : *p;
760 if (EQ(st, fresh))
761 coldp = p;
762
763 /* is there an EOL and/or BOL between lastc and c? */
764 flagch = '\0';
765 i = 0;
766 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
767 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
768 flagch = BOL;
769 i = m->g->nbol;
770 }
771 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
772 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
773 flagch = (flagch == BOL) ? BOLEOL : EOL;
774 i += m->g->neol;
775 }
776 if (i != 0) {
777 for (; i > 0; i--)
778 st = step(m->g, startst, stopst, st, flagch, st);
779 SP("boleol", st, c);
780 }
781
782 /* how about a word boundary? */
783 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
784 (c != OUT && ISWORD(c)) ) {
785 flagch = BOW;
786 }
787 if ( (lastc != OUT && ISWORD(lastc)) &&
788 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
789 flagch = EOW;
790 }
791 if (flagch == BOW || flagch == EOW) {
792 st = step(m->g, startst, stopst, st, flagch, st);
793 SP("boweow", st, c);
794 }
795
796 /* are we done? */
797 if (ISSET(st, stopst) || p == stop)
798 break; /* NOTE BREAK OUT */
799
800 /* no, we must deal with this character */
801 ASSIGN(tmp, st);
802 ASSIGN(st, fresh);
803 assert(c != OUT);
804 st = step(m->g, startst, stopst, tmp, c, st);
805 SP("aft", st, c);
806 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
807 p++;
808 }
809
810 assert(coldp != NULL);
811 m->coldp = coldp;
812 if (ISSET(st, stopst))
813 return(p+1);
814 else
815 return(NULL);
816 }
817
818 /*
819 - slow - step through the string more deliberately
820 == static char *slow(struct match *m, char *start, \
821 == char *stop, sopno startst, sopno stopst);
822 */
823 static char * /* where it ended */
824 slow(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
825 {
826 states st = m->st;
827 states empty = m->empty;
828 states tmp = m->tmp;
829 char *p = start;
830 int c = (start == m->beginp) ? OUT : *(start-1);
831 int lastc; /* previous c */
832 int flagch;
833 int i;
834 char *matchp; /* last p at which a match ended */
835
836 AT("slow", start, stop, startst, stopst);
837 CLEAR(st);
838 SET1(st, startst);
839 SP("sstart", st, *p);
840 st = step(m->g, startst, stopst, st, NOTHING, st);
841 matchp = NULL;
842 for (;;) {
843 /* next character */
844 lastc = c;
845 c = (p == m->endp) ? OUT : *p;
846
847 /* is there an EOL and/or BOL between lastc and c? */
848 flagch = '\0';
849 i = 0;
850 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
851 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
852 flagch = BOL;
853 i = m->g->nbol;
854 }
855 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
856 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
857 flagch = (flagch == BOL) ? BOLEOL : EOL;
858 i += m->g->neol;
859 }
860 if (i != 0) {
861 for (; i > 0; i--)
862 st = step(m->g, startst, stopst, st, flagch, st);
863 SP("sboleol", st, c);
864 }
865
866 /* how about a word boundary? */
867 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
868 (c != OUT && ISWORD(c)) ) {
869 flagch = BOW;
870 }
871 if ( (lastc != OUT && ISWORD(lastc)) &&
872 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
873 flagch = EOW;
874 }
875 if (flagch == BOW || flagch == EOW) {
876 st = step(m->g, startst, stopst, st, flagch, st);
877 SP("sboweow", st, c);
878 }
879
880 /* are we done? */
881 if (ISSET(st, stopst))
882 matchp = p;
883 if (EQ(st, empty) || p == stop)
884 break; /* NOTE BREAK OUT */
885
886 /* no, we must deal with this character */
887 ASSIGN(tmp, st);
888 ASSIGN(st, empty);
889 assert(c != OUT);
890 st = step(m->g, startst, stopst, tmp, c, st);
891 SP("saft", st, c);
892 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
893 p++;
894 }
895
896 return(matchp);
897 }
898
899
900 /*
901 - step - map set of states reachable before char to set reachable after
902 == static states step(struct re_guts *g, sopno start, sopno stop, \
903 == states bef, int ch, states aft);
904 == #define BOL (OUT+1)
905 == #define EOL (BOL+1)
906 == #define BOLEOL (BOL+2)
907 == #define NOTHING (BOL+3)
908 == #define BOW (BOL+4)
909 == #define EOW (BOL+5)
910 == #define CODEMAX (BOL+5) // highest code used
911 == #define NONCHAR(c) ((c) > CHAR_MAX)
912 == #define NNONCHAR (CODEMAX-CHAR_MAX)
913 */
914 static states
915 step(struct re_guts *g,
916 sopno start, /* start state within strip */
917 sopno stop, /* state after stop state within strip */
918 states bef, /* states reachable before */
919 int ch, /* character or NONCHAR code */
920 states aft) /* states already known reachable after */
921 {
922 cset *cs;
923 sop s;
924 sopno pc;
925 onestate here; /* note, macros know this name */
926 sopno look;
927 int i;
928
929 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
930 s = g->strip[pc];
931 switch (OP(s)) {
932 case OEND:
933 assert(pc == stop-1);
934 break;
935 case OCHAR:
936 /* only characters can match */
937 assert(!NONCHAR(ch) || ch != (char)OPND(s));
938 if (ch == (char)OPND(s))
939 FWD(aft, bef, 1);
940 break;
941 case OBOL:
942 if (ch == BOL || ch == BOLEOL)
943 FWD(aft, bef, 1);
944 break;
945 case OEOL:
946 if (ch == EOL || ch == BOLEOL)
947 FWD(aft, bef, 1);
948 break;
949 case OBOW:
950 if (ch == BOW)
951 FWD(aft, bef, 1);
952 break;
953 case OEOW:
954 if (ch == EOW)
955 FWD(aft, bef, 1);
956 break;
957 case OANY:
958 if (!NONCHAR(ch))
959 FWD(aft, bef, 1);
960 break;
961 case OANYOF:
962 cs = &g->sets[OPND(s)];
963 if (!NONCHAR(ch) && CHIN(cs, ch))
964 FWD(aft, bef, 1);
965 break;
966 case OBACK_: /* ignored here */
967 case O_BACK:
968 FWD(aft, aft, 1);
969 break;
970 case OPLUS_: /* forward, this is just an empty */
971 FWD(aft, aft, 1);
972 break;
973 case O_PLUS: /* both forward and back */
974 FWD(aft, aft, 1);
975 i = ISSETBACK(aft, OPND(s));
976 BACK(aft, aft, OPND(s));
977 if (!i && ISSETBACK(aft, OPND(s))) {
978 /* oho, must reconsider loop body */
979 pc -= OPND(s) + 1;
980 INIT(here, pc);
981 }
982 break;
983 case OQUEST_: /* two branches, both forward */
984 FWD(aft, aft, 1);
985 FWD(aft, aft, OPND(s));
986 break;
987 case O_QUEST: /* just an empty */
988 FWD(aft, aft, 1);
989 break;
990 case OLPAREN: /* not significant here */
991 case ORPAREN:
992 FWD(aft, aft, 1);
993 break;
994 case OCH_: /* mark the first two branches */
995 FWD(aft, aft, 1);
996 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
997 FWD(aft, aft, OPND(s));
998 break;
999 case OOR1: /* done a branch, find the O_CH */
1000 if (ISSTATEIN(aft, here)) {
1001 for (look = 1;
1002 OP(s = g->strip[pc+look]) != O_CH;
1003 look += OPND(s))
1004 assert(OP(s) == OOR2);
1005 FWD(aft, aft, look);
1006 }
1007 break;
1008 case OOR2: /* propagate OCH_'s marking */
1009 FWD(aft, aft, 1);
1010 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
1011 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1012 FWD(aft, aft, OPND(s));
1013 }
1014 break;
1015 case O_CH: /* just empty */
1016 FWD(aft, aft, 1);
1017 break;
1018 default: /* ooooops... */
1019 assert(nope);
1020 break;
1021 }
1022 }
1023
1024 return(aft);
1025 }
1026
1027 #ifdef REDEBUG
1028 /*
1029 - print - print a set of states
1030 == #ifdef REDEBUG
1031 == static void print(struct match *m, char *caption, states st, \
1032 == int ch, FILE *d);
1033 == #endif
1034 */
1035 static void
1036 print(struct match *m, char *caption, states st, int ch, FILE *d)
1037 {
1038 struct re_guts *g = m->g;
1039 int i;
1040 int first = 1;
1041
1042 if (!(m->eflags&REG_TRACE))
1043 return;
1044
1045 fprintf(d, "%s", caption);
1046 if (ch != '\0')
1047 fprintf(d, " %s", pchar(ch));
1048 for (i = 0; i < g->nstates; i++)
1049 if (ISSET(st, i)) {
1050 fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
1051 first = 0;
1052 }
1053 fprintf(d, "\n");
1054 }
1055
1056 /*
1057 - at - print current situation
1058 == #ifdef REDEBUG
1059 == static void at(struct match *m, char *title, char *start, char *stop, \
1060 == sopno startst, sopno stopst);
1061 == #endif
1062 */
1063 static void
1064 at(struct match *m, char *title, char *start, char *stop, sopno startst,
1065 sopno stopst)
1066 {
1067 if (!(m->eflags&REG_TRACE))
1068 return;
1069
1070 printf("%s %s-", title, pchar(*start));
1071 printf("%s ", pchar(*stop));
1072 printf("%ld-%ld\n", (long)startst, (long)stopst);
1073 }
1074
1075 #ifndef PCHARDONE
1076 #define PCHARDONE /* never again */
1077 /*
1078 - pchar - make a character printable
1079 == #ifdef REDEBUG
1080 == static char *pchar(int ch);
1081 == #endif
1082 *
1083 * Is this identical to regchar() over in debug.c? Well, yes. But a
1084 * duplicate here avoids having a debugging-capable regexec.o tied to
1085 * a matching debug.o, and this is convenient. It all disappears in
1086 * the non-debug compilation anyway, so it doesn't matter much.
1087 */
1088 static char * /* -> representation */
1089 pchar(int ch)
1090 {
1091 static char pbuf[10];
1092
1093 if (isprint((uch)ch) || ch == ' ')
1094 sprintf(pbuf, "%c", ch);
1095 else
1096 sprintf(pbuf, "\\%o", ch);
1097 return(pbuf);
1098 }
1099 #endif
1100 #endif
1101
1102 #undef matcher
1103 #undef fast
1104 #undef slow
1105 #undef dissect
1106 #undef backref
1107 #undef step
1108 #undef print
1109 #undef at
1110 #undef match
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