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r6831@lvps87-230-33-50: verhaegs | 2008-02-03 14:08:57 +0100
[tangerine.git] / compiler / clib / regex / engine.c
blob20327558768d39f6c3c31829ed80e5b3d5de4e9d
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 1.21 2007/05/25 12:44:58 delphij 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 /* this loop does only one repetition except for backrefs */
251 for (;;) {
252 endp = fast(m, start, stop, gf, gl);
253 if (endp == NULL) { /* a miss */
254 if (m->pmatch != NULL)
255 free((char *)m->pmatch);
256 if (m->lastpos != NULL)
257 free((char *)m->lastpos);
258 STATETEARDOWN(m);
259 return(REG_NOMATCH);
260 }
261 if (nmatch == 0 && !g->backrefs)
262 break; /* no further info needed */
263
264 /* where? */
265 assert(m->coldp != NULL);
266 for (;;) {
267 NOTE("finding start");
268 endp = slow(m, m->coldp, stop, gf, gl);
269 if (endp != NULL)
270 break;
271 assert(m->coldp < m->endp);
272 m->coldp += XMBRTOWC(NULL, m->coldp,
273 m->endp - m->coldp, &m->mbs, 0);
274 }
275 if (nmatch == 1 && !g->backrefs)
276 break; /* no further info needed */
277
278 /* oh my, he wants the subexpressions... */
279 if (m->pmatch == NULL)
280 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
281 sizeof(regmatch_t));
282 if (m->pmatch == NULL) {
283 STATETEARDOWN(m);
284 return(REG_ESPACE);
285 }
286 for (i = 1; i <= m->g->nsub; i++)
287 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
288 if (!g->backrefs && !(m->eflags&REG_BACKR)) {
289 NOTE("dissecting");
290 dp = dissect(m, m->coldp, endp, gf, gl);
291 } else {
292 if (g->nplus > 0 && m->lastpos == NULL)
293 m->lastpos = malloc((g->nplus+1) *
294 sizeof(const char *));
295 if (g->nplus > 0 && m->lastpos == NULL) {
296 free(m->pmatch);
297 STATETEARDOWN(m);
298 return(REG_ESPACE);
299 }
300 NOTE("backref dissect");
301 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
302 }
303 if (dp != NULL)
304 break;
305
306 /* uh-oh... we couldn't find a subexpression-level match */
307 assert(g->backrefs); /* must be back references doing it */
308 assert(g->nplus == 0 || m->lastpos != NULL);
309 for (;;) {
310 if (dp != NULL || endp <= m->coldp)
311 break; /* defeat */
312 NOTE("backoff");
313 endp = slow(m, m->coldp, endp-1, gf, gl);
314 if (endp == NULL)
315 break; /* defeat */
316 /* try it on a shorter possibility */
317 #ifndef NDEBUG
318 for (i = 1; i <= m->g->nsub; i++) {
319 assert(m->pmatch[i].rm_so == -1);
320 assert(m->pmatch[i].rm_eo == -1);
321 }
322 #endif
323 NOTE("backoff dissect");
324 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
325 }
326 assert(dp == NULL || dp == endp);
327 if (dp != NULL) /* found a shorter one */
328 break;
329
330 /* despite initial appearances, there is no match here */
331 NOTE("false alarm");
332 /* recycle starting later */
333 start = m->coldp + XMBRTOWC(NULL, m->coldp,
334 stop - m->coldp, &m->mbs, 0);
335 assert(start <= stop);
336 }
337
338 /* fill in the details if requested */
339 if (nmatch > 0) {
340 pmatch[0].rm_so = m->coldp - m->offp;
341 pmatch[0].rm_eo = endp - m->offp;
342 }
343 if (nmatch > 1) {
344 assert(m->pmatch != NULL);
345 for (i = 1; i < nmatch; i++)
346 if (i <= m->g->nsub)
347 pmatch[i] = m->pmatch[i];
348 else {
349 pmatch[i].rm_so = -1;
350 pmatch[i].rm_eo = -1;
351 }
352 }
353
354 if (m->pmatch != NULL)
355 free((char *)m->pmatch);
356 if (m->lastpos != NULL)
357 free((char *)m->lastpos);
358 STATETEARDOWN(m);
359 return(0);
360 }
361
362 /*
363 - dissect - figure out what matched what, no back references
364 == static const char *dissect(struct match *m, const char *start, \
365 == const char *stop, sopno startst, sopno stopst);
366 */
367 static const char * /* == stop (success) always */
368 dissect(struct match *m,
369 const char *start,
370 const char *stop,
371 sopno startst,
372 sopno stopst)
373 {
374 int i;
375 sopno ss; /* start sop of current subRE */
376 sopno es; /* end sop of current subRE */
377 const char *sp; /* start of string matched by it */
378 const char *stp; /* string matched by it cannot pass here */
379 const char *rest; /* start of rest of string */
380 const char *tail; /* string unmatched by rest of RE */
381 sopno ssub; /* start sop of subsubRE */
382 sopno esub; /* end sop of subsubRE */
383 const char *ssp; /* start of string matched by subsubRE */
384 const char *sep; /* end of string matched by subsubRE */
385 const char *oldssp; /* previous ssp */
386 const char *dp;
387
388 AT("diss", start, stop, startst, stopst);
389 sp = start;
390 for (ss = startst; ss < stopst; ss = es) {
391 /* identify end of subRE */
392 es = ss;
393 switch (OP(m->g->strip[es])) {
394 case OPLUS_:
395 case OQUEST_:
396 es += OPND(m->g->strip[es]);
397 break;
398 case OCH_:
399 while (OP(m->g->strip[es]) != O_CH)
400 es += OPND(m->g->strip[es]);
401 break;
402 }
403 es++;
404
405 /* figure out what it matched */
406 switch (OP(m->g->strip[ss])) {
407 case OEND:
408 assert(nope);
409 break;
410 case OCHAR:
411 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
412 break;
413 case OBOL:
414 case OEOL:
415 case OBOW:
416 case OEOW:
417 break;
418 case OANY:
419 case OANYOF:
420 sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
421 break;
422 case OBACK_:
423 case O_BACK:
424 assert(nope);
425 break;
426 /* cases where length of match is hard to find */
427 case OQUEST_:
428 stp = stop;
429 for (;;) {
430 /* how long could this one be? */
431 rest = slow(m, sp, stp, ss, es);
432 assert(rest != NULL); /* it did match */
433 /* could the rest match the rest? */
434 tail = slow(m, rest, stop, es, stopst);
435 if (tail == stop)
436 break; /* yes! */
437 /* no -- try a shorter match for this one */
438 stp = rest - 1;
439 assert(stp >= sp); /* it did work */
440 }
441 ssub = ss + 1;
442 esub = es - 1;
443 /* did innards match? */
444 if (slow(m, sp, rest, ssub, esub) != NULL) {
445 dp = dissect(m, sp, rest, ssub, esub);
446 assert(dp == rest);
447 } else /* no */
448 assert(sp == rest);
449 sp = rest;
450 break;
451 case OPLUS_:
452 stp = stop;
453 for (;;) {
454 /* how long could this one be? */
455 rest = slow(m, sp, stp, ss, es);
456 assert(rest != NULL); /* it did match */
457 /* could the rest match the rest? */
458 tail = slow(m, rest, stop, es, stopst);
459 if (tail == stop)
460 break; /* yes! */
461 /* no -- try a shorter match for this one */
462 stp = rest - 1;
463 assert(stp >= sp); /* it did work */
464 }
465 ssub = ss + 1;
466 esub = es - 1;
467 ssp = sp;
468 oldssp = ssp;
469 for (;;) { /* find last match of innards */
470 sep = slow(m, ssp, rest, ssub, esub);
471 if (sep == NULL || sep == ssp)
472 break; /* failed or matched null */
473 oldssp = ssp; /* on to next try */
474 ssp = sep;
475 }
476 if (sep == NULL) {
477 /* last successful match */
478 sep = ssp;
479 ssp = oldssp;
480 }
481 assert(sep == rest); /* must exhaust substring */
482 assert(slow(m, ssp, sep, ssub, esub) == rest);
483 dp = dissect(m, ssp, sep, ssub, esub);
484 assert(dp == sep);
485 sp = rest;
486 break;
487 case OCH_:
488 stp = stop;
489 for (;;) {
490 /* how long could this one be? */
491 rest = slow(m, sp, stp, ss, es);
492 assert(rest != NULL); /* it did match */
493 /* could the rest match the rest? */
494 tail = slow(m, rest, stop, es, stopst);
495 if (tail == stop)
496 break; /* yes! */
497 /* no -- try a shorter match for this one */
498 stp = rest - 1;
499 assert(stp >= sp); /* it did work */
500 }
501 ssub = ss + 1;
502 esub = ss + OPND(m->g->strip[ss]) - 1;
503 assert(OP(m->g->strip[esub]) == OOR1);
504 for (;;) { /* find first matching branch */
505 if (slow(m, sp, rest, ssub, esub) == rest)
506 break; /* it matched all of it */
507 /* that one missed, try next one */
508 assert(OP(m->g->strip[esub]) == OOR1);
509 esub++;
510 assert(OP(m->g->strip[esub]) == OOR2);
511 ssub = esub + 1;
512 esub += OPND(m->g->strip[esub]);
513 if (OP(m->g->strip[esub]) == OOR2)
514 esub--;
515 else
516 assert(OP(m->g->strip[esub]) == O_CH);
517 }
518 dp = dissect(m, sp, rest, ssub, esub);
519 assert(dp == rest);
520 sp = rest;
521 break;
522 case O_PLUS:
523 case O_QUEST:
524 case OOR1:
525 case OOR2:
526 case O_CH:
527 assert(nope);
528 break;
529 case OLPAREN:
530 i = OPND(m->g->strip[ss]);
531 assert(0 < i && i <= m->g->nsub);
532 m->pmatch[i].rm_so = sp - m->offp;
533 break;
534 case ORPAREN:
535 i = OPND(m->g->strip[ss]);
536 assert(0 < i && i <= m->g->nsub);
537 m->pmatch[i].rm_eo = sp - m->offp;
538 break;
539 default: /* uh oh */
540 assert(nope);
541 break;
542 }
543 }
544
545 assert(sp == stop);
546 return(sp);
547 }
548
549 /*
550 - backref - figure out what matched what, figuring in back references
551 == static const char *backref(struct match *m, const char *start, \
552 == const char *stop, sopno startst, sopno stopst, sopno lev);
553 */
554 static const char * /* == stop (success) or NULL (failure) */
555 backref(struct match *m,
556 const char *start,
557 const char *stop,
558 sopno startst,
559 sopno stopst,
560 sopno lev, /* PLUS nesting level */
561 int rec)
562 {
563 int i;
564 sopno ss; /* start sop of current subRE */
565 const char *sp; /* start of string matched by it */
566 sopno ssub; /* start sop of subsubRE */
567 sopno esub; /* end sop of subsubRE */
568 const char *ssp; /* start of string matched by subsubRE */
569 const char *dp;
570 size_t len;
571 int hard;
572 sop s;
573 regoff_t offsave;
574 cset *cs;
575 wint_t wc;
576
577 AT("back", start, stop, startst, stopst);
578 sp = start;
579
580 /* get as far as we can with easy stuff */
581 hard = 0;
582 for (ss = startst; !hard && ss < stopst; ss++)
583 switch (OP(s = m->g->strip[ss])) {
584 case OCHAR:
585 if (sp == stop)
586 return(NULL);
587 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
588 if (wc != OPND(s))
589 return(NULL);
590 break;
591 case OANY:
592 if (sp == stop)
593 return(NULL);
594 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
595 if (wc == BADCHAR)
596 return (NULL);
597 break;
598 case OANYOF:
599 if (sp == stop)
600 return (NULL);
601 cs = &m->g->sets[OPND(s)];
602 sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
603 if (wc == BADCHAR || !CHIN(cs, wc))
604 return(NULL);
605 break;
606 case OBOL:
607 if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
608 (sp < m->endp && *(sp-1) == '\n' &&
609 (m->g->cflags&REG_NEWLINE)) )
610 { /* yes */ }
611 else
612 return(NULL);
613 break;
614 case OEOL:
615 if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
616 (sp < m->endp && *sp == '\n' &&
617 (m->g->cflags&REG_NEWLINE)) )
618 { /* yes */ }
619 else
620 return(NULL);
621 break;
622 case OBOW:
623 if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
624 (sp < m->endp && *(sp-1) == '\n' &&
625 (m->g->cflags&REG_NEWLINE)) ||
626 (sp > m->beginp &&
627 !ISWORD(*(sp-1))) ) &&
628 (sp < m->endp && ISWORD(*sp)) )
629 { /* yes */ }
630 else
631 return(NULL);
632 break;
633 case OEOW:
634 if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
635 (sp < m->endp && *sp == '\n' &&
636 (m->g->cflags&REG_NEWLINE)) ||
637 (sp < m->endp && !ISWORD(*sp)) ) &&
638 (sp > m->beginp && ISWORD(*(sp-1))) )
639 { /* yes */ }
640 else
641 return(NULL);
642 break;
643 case O_QUEST:
644 break;
645 case OOR1: /* matches null but needs to skip */
646 ss++;
647 s = m->g->strip[ss];
648 do {
649 assert(OP(s) == OOR2);
650 ss += OPND(s);
651 } while (OP(s = m->g->strip[ss]) != O_CH);
652 /* note that the ss++ gets us past the O_CH */
653 break;
654 default: /* have to make a choice */
655 hard = 1;
656 break;
657 }
658 if (!hard) { /* that was it! */
659 if (sp != stop)
660 return(NULL);
661 return(sp);
662 }
663 ss--; /* adjust for the for's final increment */
664
665 /* the hard stuff */
666 AT("hard", sp, stop, ss, stopst);
667 s = m->g->strip[ss];
668 switch (OP(s)) {
669 case OBACK_: /* the vilest depths */
670 i = OPND(s);
671 assert(0 < i && i <= m->g->nsub);
672 if (m->pmatch[i].rm_eo == -1)
673 return(NULL);
674 assert(m->pmatch[i].rm_so != -1);
675 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
676 if (len == 0 && rec++ > MAX_RECURSION)
677 return(NULL);
678 assert(stop - m->beginp >= len);
679 if (sp > stop - len)
680 return(NULL); /* not enough left to match */
681 ssp = m->offp + m->pmatch[i].rm_so;
682 if (memcmp(sp, ssp, len) != 0)
683 return(NULL);
684 while (m->g->strip[ss] != SOP(O_BACK, i))
685 ss++;
686 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
687 break;
688 case OQUEST_: /* to null or not */
689 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
690 if (dp != NULL)
691 return(dp); /* not */
692 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
693 break;
694 case OPLUS_:
695 assert(m->lastpos != NULL);
696 assert(lev+1 <= m->g->nplus);
697 m->lastpos[lev+1] = sp;
698 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
699 break;
700 case O_PLUS:
701 if (sp == m->lastpos[lev]) /* last pass matched null */
702 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
703 /* try another pass */
704 m->lastpos[lev] = sp;
705 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
706 if (dp == NULL)
707 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
708 else
709 return(dp);
710 break;
711 case OCH_: /* find the right one, if any */
712 ssub = ss + 1;
713 esub = ss + OPND(s) - 1;
714 assert(OP(m->g->strip[esub]) == OOR1);
715 for (;;) { /* find first matching branch */
716 dp = backref(m, sp, stop, ssub, esub, lev, rec);
717 if (dp != NULL)
718 return(dp);
719 /* that one missed, try next one */
720 if (OP(m->g->strip[esub]) == O_CH)
721 return(NULL); /* there is none */
722 esub++;
723 assert(OP(m->g->strip[esub]) == OOR2);
724 ssub = esub + 1;
725 esub += OPND(m->g->strip[esub]);
726 if (OP(m->g->strip[esub]) == OOR2)
727 esub--;
728 else
729 assert(OP(m->g->strip[esub]) == O_CH);
730 }
731 break;
732 case OLPAREN: /* must undo assignment if rest fails */
733 i = OPND(s);
734 assert(0 < i && i <= m->g->nsub);
735 offsave = m->pmatch[i].rm_so;
736 m->pmatch[i].rm_so = sp - m->offp;
737 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
738 if (dp != NULL)
739 return(dp);
740 m->pmatch[i].rm_so = offsave;
741 return(NULL);
742 break;
743 case ORPAREN: /* must undo assignment if rest fails */
744 i = OPND(s);
745 assert(0 < i && i <= m->g->nsub);
746 offsave = m->pmatch[i].rm_eo;
747 m->pmatch[i].rm_eo = sp - m->offp;
748 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
749 if (dp != NULL)
750 return(dp);
751 m->pmatch[i].rm_eo = offsave;
752 return(NULL);
753 break;
754 default: /* uh oh */
755 assert(nope);
756 break;
757 }
758
759 /* "can't happen" */
760 assert(nope);
761 /* NOTREACHED */
762 return "shut up gcc";
763 }
764
765 /*
766 - fast - step through the string at top speed
767 == static const char *fast(struct match *m, const char *start, \
768 == const char *stop, sopno startst, sopno stopst);
769 */
770 static const char * /* where tentative match ended, or NULL */
771 fast( struct match *m,
772 const char *start,
773 const char *stop,
774 sopno startst,
775 sopno stopst)
776 {
777 states st = m->st;
778 states fresh = m->fresh;
779 states tmp = m->tmp;
780 const char *p = start;
781 wint_t c;
782 wint_t lastc; /* previous c */
783 wint_t flagch;
784 int i;
785 const char *coldp; /* last p after which no match was underway */
786 size_t clen;
787
788 CLEAR(st);
789 SET1(st, startst);
790 st = step(m->g, startst, stopst, st, NOTHING, st);
791 ASSIGN(fresh, st);
792 SP("start", st, *p);
793 coldp = NULL;
794 if (start == m->beginp)
795 c = OUT;
796 else {
797 /*
798 * XXX Wrong if the previous character was multi-byte.
799 * Newline never is (in encodings supported by FreeBSD),
800 * so this only breaks the ISWORD tests below.
801 */
802 c = (uch)*(start - 1);
803 }
804 for (;;) {
805 /* next character */
806 lastc = c;
807 if (p == m->endp) {
808 clen = 0;
809 c = OUT;
810 } else
811 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
812 if (EQ(st, fresh))
813 coldp = p;
814
815 /* is there an EOL and/or BOL between lastc and c? */
816 flagch = '\0';
817 i = 0;
818 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
819 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
820 flagch = BOL;
821 i = m->g->nbol;
822 }
823 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
824 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
825 flagch = (flagch == BOL) ? BOLEOL : EOL;
826 i += m->g->neol;
827 }
828 if (i != 0) {
829 for (; i > 0; i--)
830 st = step(m->g, startst, stopst, st, flagch, st);
831 SP("boleol", st, c);
832 }
833
834 /* how about a word boundary? */
835 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
836 (c != OUT && ISWORD(c)) ) {
837 flagch = BOW;
838 }
839 if ( (lastc != OUT && ISWORD(lastc)) &&
840 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
841 flagch = EOW;
842 }
843 if (flagch == BOW || flagch == EOW) {
844 st = step(m->g, startst, stopst, st, flagch, st);
845 SP("boweow", st, c);
846 }
847
848 /* are we done? */
849 if (ISSET(st, stopst) || p == stop || clen > stop - p)
850 break; /* NOTE BREAK OUT */
851
852 /* no, we must deal with this character */
853 ASSIGN(tmp, st);
854 ASSIGN(st, fresh);
855 assert(c != OUT);
856 st = step(m->g, startst, stopst, tmp, c, st);
857 SP("aft", st, c);
858 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
859 p += clen;
860 }
861
862 assert(coldp != NULL);
863 m->coldp = coldp;
864 if (ISSET(st, stopst))
865 return(p+XMBRTOWC(NULL, p, stop - p, &m->mbs, 0));
866 else
867 return(NULL);
868 }
869
870 /*
871 - slow - step through the string more deliberately
872 == static const char *slow(struct match *m, const char *start, \
873 == const char *stop, sopno startst, sopno stopst);
874 */
875 static const char * /* where it ended */
876 slow( struct match *m,
877 const char *start,
878 const char *stop,
879 sopno startst,
880 sopno stopst)
881 {
882 states st = m->st;
883 states empty = m->empty;
884 states tmp = m->tmp;
885 const char *p = start;
886 wint_t c;
887 wint_t lastc; /* previous c */
888 wint_t flagch;
889 int i;
890 const char *matchp; /* last p at which a match ended */
891 size_t clen;
892
893 AT("slow", start, stop, startst, stopst);
894 CLEAR(st);
895 SET1(st, startst);
896 SP("sstart", st, *p);
897 st = step(m->g, startst, stopst, st, NOTHING, st);
898 matchp = NULL;
899 if (start == m->beginp)
900 c = OUT;
901 else {
902 /*
903 * XXX Wrong if the previous character was multi-byte.
904 * Newline never is (in encodings supported by FreeBSD),
905 * so this only breaks the ISWORD tests below.
906 */
907 c = (uch)*(start - 1);
908 }
909 for (;;) {
910 /* next character */
911 lastc = c;
912 if (p == m->endp) {
913 c = OUT;
914 clen = 0;
915 } else
916 clen = XMBRTOWC(&c, p, m->endp - p, &m->mbs, BADCHAR);
917
918 /* is there an EOL and/or BOL between lastc and c? */
919 flagch = '\0';
920 i = 0;
921 if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
922 (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
923 flagch = BOL;
924 i = m->g->nbol;
925 }
926 if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
927 (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
928 flagch = (flagch == BOL) ? BOLEOL : EOL;
929 i += m->g->neol;
930 }
931 if (i != 0) {
932 for (; i > 0; i--)
933 st = step(m->g, startst, stopst, st, flagch, st);
934 SP("sboleol", st, c);
935 }
936
937 /* how about a word boundary? */
938 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
939 (c != OUT && ISWORD(c)) ) {
940 flagch = BOW;
941 }
942 if ( (lastc != OUT && ISWORD(lastc)) &&
943 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
944 flagch = EOW;
945 }
946 if (flagch == BOW || flagch == EOW) {
947 st = step(m->g, startst, stopst, st, flagch, st);
948 SP("sboweow", st, c);
949 }
950
951 /* are we done? */
952 if (ISSET(st, stopst))
953 matchp = p;
954 if (EQ(st, empty) || p == stop || clen > stop - p)
955 break; /* NOTE BREAK OUT */
956
957 /* no, we must deal with this character */
958 ASSIGN(tmp, st);
959 ASSIGN(st, empty);
960 assert(c != OUT);
961 st = step(m->g, startst, stopst, tmp, c, st);
962 SP("saft", st, c);
963 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
964 p += clen;
965 }
966
967 return(matchp);
968 }
969
970
971 /*
972 - step - map set of states reachable before char to set reachable after
973 == static states step(struct re_guts *g, sopno start, sopno stop, \
974 == states bef, int ch, states aft);
975 == #define BOL (OUT-1)
976 == #define EOL (BOL-1)
977 == #define BOLEOL (BOL-2)
978 == #define NOTHING (BOL-3)
979 == #define BOW (BOL-4)
980 == #define EOW (BOL-5)
981 == #define BADCHAR (BOL-6)
982 == #define NONCHAR(c) ((c) <= OUT)
983 */
984 static states
985 step(struct re_guts *g,
986 sopno start, /* start state within strip */
987 sopno stop, /* state after stop state within strip */
988 states bef, /* states reachable before */
989 wint_t ch, /* character or NONCHAR code */
990 states aft) /* states already known reachable after */
991 {
992 cset *cs;
993 sop s;
994 sopno pc;
995 onestate here; /* note, macros know this name */
996 sopno look;
997 int i;
998
999 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
1000 s = g->strip[pc];
1001 switch (OP(s)) {
1002 case OEND:
1003 assert(pc == stop-1);
1004 break;
1005 case OCHAR:
1006 /* only characters can match */
1007 assert(!NONCHAR(ch) || ch != OPND(s));
1008 if (ch == OPND(s))
1009 FWD(aft, bef, 1);
1010 break;
1011 case OBOL:
1012 if (ch == BOL || ch == BOLEOL)
1013 FWD(aft, bef, 1);
1014 break;
1015 case OEOL:
1016 if (ch == EOL || ch == BOLEOL)
1017 FWD(aft, bef, 1);
1018 break;
1019 case OBOW:
1020 if (ch == BOW)
1021 FWD(aft, bef, 1);
1022 break;
1023 case OEOW:
1024 if (ch == EOW)
1025 FWD(aft, bef, 1);
1026 break;
1027 case OANY:
1028 if (!NONCHAR(ch))
1029 FWD(aft, bef, 1);
1030 break;
1031 case OANYOF:
1032 cs = &g->sets[OPND(s)];
1033 if (!NONCHAR(ch) && CHIN(cs, ch))
1034 FWD(aft, bef, 1);
1035 break;
1036 case OBACK_: /* ignored here */
1037 case O_BACK:
1038 FWD(aft, aft, 1);
1039 break;
1040 case OPLUS_: /* forward, this is just an empty */
1041 FWD(aft, aft, 1);
1042 break;
1043 case O_PLUS: /* both forward and back */
1044 FWD(aft, aft, 1);
1045 i = ISSETBACK(aft, OPND(s));
1046 BACK(aft, aft, OPND(s));
1047 if (!i && ISSETBACK(aft, OPND(s))) {
1048 /* oho, must reconsider loop body */
1049 pc -= OPND(s) + 1;
1050 INIT(here, pc);
1051 }
1052 break;
1053 case OQUEST_: /* two branches, both forward */
1054 FWD(aft, aft, 1);
1055 FWD(aft, aft, OPND(s));
1056 break;
1057 case O_QUEST: /* just an empty */
1058 FWD(aft, aft, 1);
1059 break;
1060 case OLPAREN: /* not significant here */
1061 case ORPAREN:
1062 FWD(aft, aft, 1);
1063 break;
1064 case OCH_: /* mark the first two branches */
1065 FWD(aft, aft, 1);
1066 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1067 FWD(aft, aft, OPND(s));
1068 break;
1069 case OOR1: /* done a branch, find the O_CH */
1070 if (ISSTATEIN(aft, here)) {
1071 for (look = 1;
1072 OP(s = g->strip[pc+look]) != O_CH;
1073 look += OPND(s))
1074 assert(OP(s) == OOR2);
1075 FWD(aft, aft, look);
1076 }
1077 break;
1078 case OOR2: /* propagate OCH_'s marking */
1079 FWD(aft, aft, 1);
1080 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
1081 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
1082 FWD(aft, aft, OPND(s));
1083 }
1084 break;
1085 case O_CH: /* just empty */
1086 FWD(aft, aft, 1);
1087 break;
1088 default: /* ooooops... */
1089 assert(nope);
1090 break;
1091 }
1092 }
1093
1094 return(aft);
1095 }
1096
1097 #ifdef REDEBUG
1098 /*
1099 - print - print a set of states
1100 == #ifdef REDEBUG
1101 == static void print(struct match *m, const char *caption, states st, \
1102 == int ch, FILE *d);
1103 == #endif
1104 */
1105 static void
1106 print(struct match *m,
1107 const char *caption,
1108 states st,
1109 int ch,
1110 FILE *d)
1111 {
1112 struct re_guts *g = m->g;
1113 int i;
1114 int first = 1;
1115
1116 if (!(m->eflags&REG_TRACE))
1117 return;
1118
1119 fprintf(d, "%s", caption);
1120 if (ch != '\0')
1121 fprintf(d, " %s", pchar(ch));
1122 for (i = 0; i < g->nstates; i++)
1123 if (ISSET(st, i)) {
1124 fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
1125 first = 0;
1126 }
1127 fprintf(d, "\n");
1128 }
1129
1130 /*
1131 - at - print current situation
1132 == #ifdef REDEBUG
1133 == static void at(struct match *m, const char *title, const char *start, \
1134 == const char *stop, sopno startst, sopno stopst);
1135 == #endif
1136 */
1137 static void
1138 at( struct match *m,
1139 const char *title,
1140 const char *start,
1141 const char *stop,
1142 sopno startst,
1143 sopno stopst)
1144 {
1145 if (!(m->eflags&REG_TRACE))
1146 return;
1147
1148 printf("%s %s-", title, pchar(*start));
1149 printf("%s ", pchar(*stop));
1150 printf("%ld-%ld\n", (long)startst, (long)stopst);
1151 }
1152
1153 #ifndef PCHARDONE
1154 #define PCHARDONE /* never again */
1155 /*
1156 - pchar - make a character printable
1157 == #ifdef REDEBUG
1158 == static const char *pchar(int ch);
1159 == #endif
1160 *
1161 * Is this identical to regchar() over in debug.c? Well, yes. But a
1162 * duplicate here avoids having a debugging-capable regexec.o tied to
1163 * a matching debug.o, and this is convenient. It all disappears in
1164 * the non-debug compilation anyway, so it doesn't matter much.
1165 */
1166 static const char * /* -> representation */
1167 pchar(int ch)
1168 {
1169 static char pbuf[10];
1170
1171 if (isprint((uch)ch) || ch == ' ')
1172 sprintf(pbuf, "%c", ch);
1173 else
1174 sprintf(pbuf, "\\%o", ch);
1175 return(pbuf);
1176 }
1177 #endif
1178 #endif
1179
1180 #undef matcher
1181 #undef fast
1182 #undef slow
1183 #undef dissect
1184 #undef backref
1185 #undef step
1186 #undef print
1187 #undef at
1188 #undef match
A totally sweet operating system