1 /* $OpenBSD: engine.c,v 1.26 2020/12/28 21:41:55 millert Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
5 * Copyright (c) 1992, 1993, 1994
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Henry Spencer.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)engine.c 8.5 (Berkeley) 3/20/94
36 */
37
38 /*
39 * The matching engine and friends. This file is #included by regexec.c
40 * after suitable #defines of a variety of macros used herein, so that
41 * different state representations can be used without duplicating masses
42 * of code.
43 */
44
45 #ifdef SNAMES
46 #define matcher smatcher
47 #define fast sfast
48 #define slow sslow
49 #define dissect sdissect
50 #define backref sbackref
51 #define step sstep
52 #define print sprint
53 #define at sat
54 #define match smat
55 #define nope snope
56 #endif
57 #ifdef LNAMES
58 #define matcher lmatcher
59 #define fast lfast
60 #define slow lslow
61 #define dissect ldissect
62 #define backref lbackref
63 #define step lstep
64 #define print lprint
65 #define at lat
66 #define match lmat
67 #define nope lnope
68 #endif
69
70 /* another structure passed up and down to avoid zillions of parameters */
71 struct match {
72 struct re_guts *g;
73 int eflags;
74 regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
75 const char *offp; /* offsets work from here */
76 const char *beginp; /* start of string -- virtual NUL precedes */
77 const char *endp; /* end of string -- virtual NUL here */
78 const char *coldp; /* can be no match starting before here */
79 const char **lastpos; /* [nplus+1] */
80 STATEVARS;
81 states st; /* current states */
82 states fresh; /* states for a fresh start */
83 states tmp; /* temporary */
84 states empty; /* empty set of states */
85 };
86
87 static int matcher(struct re_guts *, const char *, size_t, regmatch_t[], int);
88 static const char *dissect(struct match *, const char *, const char *, sopno,
89 sopno);
90 static const char *backref(struct match *, const char *, const char *, sopno,
91 sopno, sopno, int);
92 static const char *fast(struct match *, const char *, const char *, sopno,
93 sopno);
94 static const char *slow(struct match *, const char *, const char *, sopno,
95 sopno);
96 static states step(struct re_guts *, sopno, sopno, states, int, states);
97 #define MAX_RECURSION 100
98 #define BOL (OUT+1)
99 #define EOL (BOL+1)
100 #define BOLEOL (BOL+2)
101 #define NOTHING (BOL+3)
102 #define BOW (BOL+4)
103 #define EOW (BOL+5)
104 /* update nonchars[] array below when adding fake chars here */
105 #define CODEMAX (BOL+5) /* highest code used */
106 #define NONCHAR(c) ((c) > CHAR_MAX)
107 #define NNONCHAR (CODEMAX-CHAR_MAX)
108 #ifdef REDEBUG
109 static void print(struct match *, const char *, states, int, FILE *);
110 #endif
111 #ifdef REDEBUG
112 static void at(struct match *, const char *, const char *, const char *,
113 sopno, sopno);
114 #endif
115 #ifdef REDEBUG
116 static const char *pchar(int);
117 #endif
118
119 #ifdef REDEBUG
120 #define SP(t, s, c) print(m, t, s, c, stdout)
121 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
122 #define NOTE(str) { if (m->eflags®_TRACE) (void)printf("=%s\n", (str)); }
123 static int nope = 0;
124 #else
125 #define SP(t, s, c) /* nothing */
126 #define AT(t, p1, p2, s1, s2) /* nothing */
127 #define NOTE(s) /* nothing */
128 #endif
129
130 /*
131 - matcher - the actual matching engine
132 */
133 static int /* 0 success, REG_NOMATCH failure */
matcher(struct re_guts * g,const char * string,size_t nmatch,regmatch_t pmatch[],int eflags)134 matcher(struct re_guts *g, const char *string, size_t nmatch,
135 regmatch_t pmatch[], int eflags)
136 {
137 const char *endp;
138 int i;
139 struct match mv;
140 struct match *m = &mv;
141 const char *dp;
142 const sopno gf = g->firststate+1; /* +1 for OEND */
143 const sopno gl = g->laststate;
144 const char *start;
145 const char *stop;
146
147 /* simplify the situation where possible */
148 if (g->cflags®_NOSUB)
149 nmatch = 0;
150 if (eflags®_STARTEND) {
151 start = string + pmatch[0].rm_so;
152 stop = string + pmatch[0].rm_eo;
153 } else {
154 start = string;
155 stop = start + strlen(start);
156 }
157 if (stop < start)
158 return(REG_INVARG);
159
160 /* prescreening; this does wonders for this rather slow code */
161 if (g->must != NULL) {
162 for (dp = start; dp < stop; dp++)
163 if (*dp == g->must[0] && stop - dp >= g->mlen &&
164 memcmp(dp, g->must, g->mlen) == 0)
165 break;
166 if (dp == stop) /* we didn't find g->must */
167 return(REG_NOMATCH);
168 }
169
170 /* match struct setup */
171 m->g = g;
172 m->eflags = eflags;
173 m->pmatch = NULL;
174 m->lastpos = NULL;
175 m->offp = string;
176 m->beginp = start;
177 m->endp = stop;
178 STATESETUP(m, 4);
179 SETUP(m->st);
180 SETUP(m->fresh);
181 SETUP(m->tmp);
182 SETUP(m->empty);
183 CLEAR(m->empty);
184
185 /* this loop does only one repetition except for backrefs */
186 for (;;) {
187 endp = fast(m, start, stop, gf, gl);
188 if (endp == NULL) { /* a miss */
189 free(m->pmatch);
190 free(m->lastpos);
191 STATETEARDOWN(m);
192 return(REG_NOMATCH);
193 }
194 if (nmatch == 0 && !g->backrefs)
195 break; /* no further info needed */
196
197 /* where? */
198 assert(m->coldp != NULL);
199 for (;;) {
200 NOTE("finding start");
201 endp = slow(m, m->coldp, stop, gf, gl);
202 if (endp != NULL)
203 break;
204 assert(m->coldp < m->endp);
205 m->coldp++;
206 }
207 if (nmatch == 1 && !g->backrefs)
208 break; /* no further info needed */
209
210 /* oh my, he wants the subexpressions... */
211 if (m->pmatch == NULL)
212 m->pmatch = reallocarray(NULL, m->g->nsub + 1,
213 sizeof(regmatch_t));
214 if (m->pmatch == NULL) {
215 STATETEARDOWN(m);
216 return(REG_ESPACE);
217 }
218 for (i = 1; i <= m->g->nsub; i++)
219 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
220 if (!g->backrefs && !(m->eflags®_BACKR)) {
221 NOTE("dissecting");
222 dp = dissect(m, m->coldp, endp, gf, gl);
223 } else {
224 if (g->nplus > 0 && m->lastpos == NULL)
225 m->lastpos = reallocarray(NULL,
226 g->nplus+1, sizeof(char *));
227 if (g->nplus > 0 && m->lastpos == NULL) {
228 free(m->pmatch);
229 STATETEARDOWN(m);
230 return(REG_ESPACE);
231 }
232 NOTE("backref dissect");
233 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
234 }
235 if (dp != NULL)
236 break;
237
238 /* uh-oh... we couldn't find a subexpression-level match */
239 assert(g->backrefs); /* must be back references doing it */
240 assert(g->nplus == 0 || m->lastpos != NULL);
241 for (;;) {
242 if (dp != NULL || endp <= m->coldp)
243 break; /* defeat */
244 NOTE("backoff");
245 endp = slow(m, m->coldp, endp-1, gf, gl);
246 if (endp == NULL)
247 break; /* defeat */
248 /* try it on a shorter possibility */
249 #ifndef NDEBUG
250 for (i = 1; i <= m->g->nsub; i++) {
251 assert(m->pmatch[i].rm_so == -1);
252 assert(m->pmatch[i].rm_eo == -1);
253 }
254 #endif
255 NOTE("backoff dissect");
256 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
257 }
258 assert(dp == NULL || dp == endp);
259 if (dp != NULL) /* found a shorter one */
260 break;
261
262 /* despite initial appearances, there is no match here */
263 NOTE("false alarm");
264 if (m->coldp == stop)
265 break;
266 start = m->coldp + 1; /* recycle starting later */
267 }
268
269 /* fill in the details if requested */
270 if (nmatch > 0) {
271 pmatch[0].rm_so = m->coldp - m->offp;
272 pmatch[0].rm_eo = endp - m->offp;
273 }
274 if (nmatch > 1) {
275 assert(m->pmatch != NULL);
276 for (i = 1; i < nmatch; i++)
277 if (i <= m->g->nsub)
278 pmatch[i] = m->pmatch[i];
279 else {
280 pmatch[i].rm_so = -1;
281 pmatch[i].rm_eo = -1;
282 }
283 }
284
285 free(m->pmatch);
286 free(m->lastpos);
287 STATETEARDOWN(m);
288 return(0);
289 }
290
291 /*
292 - dissect - figure out what matched what, no back references
293 */
294 static const char * /* == stop (success) always */
dissect(struct match * m,const char * start,const char * stop,sopno startst,sopno stopst)295 dissect(struct match *m, const char *start, const char *stop, sopno startst,
296 sopno stopst)
297 {
298 int i;
299 sopno ss; /* start sop of current subRE */
300 sopno es; /* end sop of current subRE */
301 const char *sp; /* start of string matched by it */
302 const char *stp; /* string matched by it cannot pass here */
303 const char *rest; /* start of rest of string */
304 const char *tail; /* string unmatched by rest of RE */
305 sopno ssub; /* start sop of subsubRE */
306 sopno esub; /* end sop of subsubRE */
307 const char *ssp; /* start of string matched by subsubRE */
308 const char *sep; /* end of string matched by subsubRE */
309 const char *oldssp; /* previous ssp */
310 const char *dp;
311
312 AT("diss", start, stop, startst, stopst);
313 sp = start;
314 for (ss = startst; ss < stopst; ss = es) {
315 /* identify end of subRE */
316 es = ss;
317 switch (OP(m->g->strip[es])) {
318 case OPLUS_:
319 case OQUEST_:
320 es += OPND(m->g->strip[es]);
321 break;
322 case OCH_:
323 while (OP(m->g->strip[es]) != O_CH)
324 es += OPND(m->g->strip[es]);
325 break;
326 }
327 es++;
328
329 /* figure out what it matched */
330 switch (OP(m->g->strip[ss])) {
331 case OEND:
332 assert(nope);
333 break;
334 case OCHAR:
335 sp++;
336 break;
337 case OBOL:
338 case OEOL:
339 case OBOW:
340 case OEOW:
341 break;
342 case OANY:
343 case OANYOF:
344 sp++;
345 break;
346 case OBACK_:
347 case O_BACK:
348 assert(nope);
349 break;
350 /* cases where length of match is hard to find */
351 case OQUEST_:
352 stp = stop;
353 for (;;) {
354 /* how long could this one be? */
355 rest = slow(m, sp, stp, ss, es);
356 assert(rest != NULL); /* it did match */
357 /* could the rest match the rest? */
358 tail = slow(m, rest, stop, es, stopst);
359 if (tail == stop)
360 break; /* yes! */
361 /* no -- try a shorter match for this one */
362 stp = rest - 1;
363 assert(stp >= sp); /* it did work */
364 }
365 ssub = ss + 1;
366 esub = es - 1;
367 /* did innards match? */
368 if (slow(m, sp, rest, ssub, esub) != NULL) {
369 dp = dissect(m, sp, rest, ssub, esub);
370 assert(dp == rest);
371 } else /* no */
372 assert(sp == rest);
373 sp = rest;
374 break;
375 case OPLUS_:
376 stp = stop;
377 for (;;) {
378 /* how long could this one be? */
379 rest = slow(m, sp, stp, ss, es);
380 assert(rest != NULL); /* it did match */
381 /* could the rest match the rest? */
382 tail = slow(m, rest, stop, es, stopst);
383 if (tail == stop)
384 break; /* yes! */
385 /* no -- try a shorter match for this one */
386 stp = rest - 1;
387 assert(stp >= sp); /* it did work */
388 }
389 ssub = ss + 1;
390 esub = es - 1;
391 ssp = sp;
392 oldssp = ssp;
393 for (;;) { /* find last match of innards */
394 sep = slow(m, ssp, rest, ssub, esub);
395 if (sep == NULL || sep == ssp)
396 break; /* failed or matched null */
397 oldssp = ssp; /* on to next try */
398 ssp = sep;
399 }
400 if (sep == NULL) {
401 /* last successful match */
402 sep = ssp;
403 ssp = oldssp;
404 }
405 assert(sep == rest); /* must exhaust substring */
406 assert(slow(m, ssp, sep, ssub, esub) == rest);
407 dp = dissect(m, ssp, sep, ssub, esub);
408 assert(dp == sep);
409 sp = rest;
410 break;
411 case OCH_:
412 stp = stop;
413 for (;;) {
414 /* how long could this one be? */
415 rest = slow(m, sp, stp, ss, es);
416 assert(rest != NULL); /* it did match */
417 /* could the rest match the rest? */
418 tail = slow(m, rest, stop, es, stopst);
419 if (tail == stop)
420 break; /* yes! */
421 /* no -- try a shorter match for this one */
422 stp = rest - 1;
423 assert(stp >= sp); /* it did work */
424 }
425 ssub = ss + 1;
426 esub = ss + OPND(m->g->strip[ss]) - 1;
427 assert(OP(m->g->strip[esub]) == OOR1);
428 for (;;) { /* find first matching branch */
429 if (slow(m, sp, rest, ssub, esub) == rest)
430 break; /* it matched all of it */
431 /* that one missed, try next one */
432 assert(OP(m->g->strip[esub]) == OOR1);
433 esub++;
434 assert(OP(m->g->strip[esub]) == OOR2);
435 ssub = esub + 1;
436 esub += OPND(m->g->strip[esub]);
437 if (OP(m->g->strip[esub]) == OOR2)
438 esub--;
439 else
440 assert(OP(m->g->strip[esub]) == O_CH);
441 }
442 dp = dissect(m, sp, rest, ssub, esub);
443 assert(dp == rest);
444 sp = rest;
445 break;
446 case O_PLUS:
447 case O_QUEST:
448 case OOR1:
449 case OOR2:
450 case O_CH:
451 assert(nope);
452 break;
453 case OLPAREN:
454 i = OPND(m->g->strip[ss]);
455 assert(0 < i && i <= m->g->nsub);
456 m->pmatch[i].rm_so = sp - m->offp;
457 break;
458 case ORPAREN:
459 i = OPND(m->g->strip[ss]);
460 assert(0 < i && i <= m->g->nsub);
461 m->pmatch[i].rm_eo = sp - m->offp;
462 break;
463 default: /* uh oh */
464 assert(nope);
465 break;
466 }
467 }
468
469 assert(sp == stop);
470 return(sp);
471 }
472
473 /*
474 - backref - figure out what matched what, figuring in back references
475 */
476 static const char * /* == stop (success) or NULL (failure) */
backref(struct match * m,const char * start,const char * stop,sopno startst,sopno stopst,sopno lev,int rec)477 backref(struct match *m, const char *start, const char *stop, sopno startst,
478 sopno stopst, sopno lev, int rec) /* PLUS nesting level */
479 {
480 int i;
481 sopno ss; /* start sop of current subRE */
482 const char *sp; /* start of string matched by it */
483 sopno ssub; /* start sop of subsubRE */
484 sopno esub; /* end sop of subsubRE */
485 const char *ssp;/* start of string matched by subsubRE */
486 const char *dp;
487 size_t len;
488 int hard;
489 sop s;
490 regoff_t offsave;
491 cset *cs;
492
493 AT("back", start, stop, startst, stopst);
494 sp = start;
495
496 /* get as far as we can with easy stuff */
497 hard = 0;
498 for (ss = startst; !hard && ss < stopst; ss++)
499 switch (OP(s = m->g->strip[ss])) {
500 case OCHAR:
501 if (sp == stop || *sp++ != (char)OPND(s))
502 return(NULL);
503 break;
504 case OANY:
505 if (sp == stop)
506 return(NULL);
507 sp++;
508 break;
509 case OANYOF:
510 cs = &m->g->sets[OPND(s)];
511 if (sp == stop || !CHIN(cs, *sp++))
512 return(NULL);
513 break;
514 case OBOL:
515 if ((sp == m->beginp && !(m->eflags®_NOTBOL)) ||
516 (sp > m->offp && sp < m->endp &&
517 *(sp-1) == '\n' && (m->g->cflags®_NEWLINE)))
518 { /* yes */ }
519 else
520 return(NULL);
521 break;
522 case OEOL:
523 if ( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
524 (sp < m->endp && *sp == '\n' &&
525 (m->g->cflags®_NEWLINE)) )
526 { /* yes */ }
527 else
528 return(NULL);
529 break;
530 case OBOW:
531 if (sp < m->endp && ISWORD(*sp) &&
532 ((sp == m->beginp && !(m->eflags®_NOTBOL)) ||
533 (sp > m->offp && !ISWORD(*(sp-1)))))
534 { /* yes */ }
535 else
536 return(NULL);
537 break;
538 case OEOW:
539 if (( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
540 (sp < m->endp && *sp == '\n' &&
541 (m->g->cflags®_NEWLINE)) ||
542 (sp < m->endp && !ISWORD(*sp)) ) &&
543 (sp > m->beginp && ISWORD(*(sp-1))) )
544 { /* yes */ }
545 else
546 return(NULL);
547 break;
548 case O_QUEST:
549 break;
550 case OOR1: /* matches null but needs to skip */
551 ss++;
552 s = m->g->strip[ss];
553 do {
554 assert(OP(s) == OOR2);
555 ss += OPND(s);
556 } while (OP(s = m->g->strip[ss]) != O_CH);
557 /* note that the ss++ gets us past the O_CH */
558 break;
559 default: /* have to make a choice */
560 hard = 1;
561 break;
562 }
563 if (!hard) { /* that was it! */
564 if (sp != stop)
565 return(NULL);
566 return(sp);
567 }
568 ss--; /* adjust for the for's final increment */
569
570 /* the hard stuff */
571 AT("hard", sp, stop, ss, stopst);
572 s = m->g->strip[ss];
573 switch (OP(s)) {
574 case OBACK_: /* the vilest depths */
575 i = OPND(s);
576 assert(0 < i && i <= m->g->nsub);
577 if (m->pmatch[i].rm_eo == -1)
578 return(NULL);
579 assert(m->pmatch[i].rm_so != -1);
580 len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
581 if (len == 0 && rec++ > MAX_RECURSION)
582 return(NULL);
583 assert(stop - m->beginp >= len);
584 if (sp > stop - len)
585 return(NULL); /* not enough left to match */
586 ssp = m->offp + m->pmatch[i].rm_so;
587 if (memcmp(sp, ssp, len) != 0)
588 return(NULL);
589 while (m->g->strip[ss] != SOP(O_BACK, i))
590 ss++;
591 return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
592 break;
593 case OQUEST_: /* to null or not */
594 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
595 if (dp != NULL)
596 return(dp); /* not */
597 return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
598 break;
599 case OPLUS_:
600 assert(m->lastpos != NULL);
601 assert(lev+1 <= m->g->nplus);
602 m->lastpos[lev+1] = sp;
603 return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
604 break;
605 case O_PLUS:
606 if (sp == m->lastpos[lev]) /* last pass matched null */
607 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
608 /* try another pass */
609 m->lastpos[lev] = sp;
610 dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
611 if (dp == NULL)
612 return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
613 else
614 return(dp);
615 break;
616 case OCH_: /* find the right one, if any */
617 ssub = ss + 1;
618 esub = ss + OPND(s) - 1;
619 assert(OP(m->g->strip[esub]) == OOR1);
620 for (;;) { /* find first matching branch */
621 dp = backref(m, sp, stop, ssub, esub, lev, rec);
622 if (dp != NULL)
623 return(dp);
624 /* that one missed, try next one */
625 if (OP(m->g->strip[esub]) == O_CH)
626 return(NULL); /* there is none */
627 esub++;
628 assert(OP(m->g->strip[esub]) == OOR2);
629 ssub = esub + 1;
630 esub += OPND(m->g->strip[esub]);
631 if (OP(m->g->strip[esub]) == OOR2)
632 esub--;
633 else
634 assert(OP(m->g->strip[esub]) == O_CH);
635 }
636 break;
637 case OLPAREN: /* must undo assignment if rest fails */
638 i = OPND(s);
639 assert(0 < i && i <= m->g->nsub);
640 offsave = m->pmatch[i].rm_so;
641 m->pmatch[i].rm_so = sp - m->offp;
642 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
643 if (dp != NULL)
644 return(dp);
645 m->pmatch[i].rm_so = offsave;
646 return(NULL);
647 break;
648 case ORPAREN: /* must undo assignment if rest fails */
649 i = OPND(s);
650 assert(0 < i && i <= m->g->nsub);
651 offsave = m->pmatch[i].rm_eo;
652 m->pmatch[i].rm_eo = sp - m->offp;
653 dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
654 if (dp != NULL)
655 return(dp);
656 m->pmatch[i].rm_eo = offsave;
657 return(NULL);
658 break;
659 default: /* uh oh */
660 assert(nope);
661 break;
662 }
663
664 /* "can't happen" */
665 assert(nope);
666 /* NOTREACHED */
667 return NULL;
668 }
669
670 /*
671 - fast - step through the string at top speed
672 */
673 static const char * /* where tentative match ended, or NULL */
fast(struct match * m,const char * start,const char * stop,sopno startst,sopno stopst)674 fast(struct match *m, const char *start, const char *stop, sopno startst,
675 sopno stopst)
676 {
677 states st = m->st;
678 states fresh = m->fresh;
679 states tmp = m->tmp;
680 const char *p = start;
681 int c;
682 int lastc; /* previous c */
683 int flagch;
684 int i;
685 const char *coldp; /* last p after which no match was underway */
686
687 if (start == m->offp || (start == m->beginp && !(m->eflags®_NOTBOL)))
688 c = OUT;
689 else
690 c = *(start-1);
691
692 CLEAR(st);
693 SET1(st, startst);
694 st = step(m->g, startst, stopst, st, NOTHING, st);
695 ASSIGN(fresh, st);
696 SP("start", st, *p);
697 coldp = NULL;
698 for (;;) {
699 /* next character */
700 lastc = c;
701 c = (p == m->endp) ? OUT : *p;
702 if (EQ(st, fresh))
703 coldp = p;
704
705 /* is there an EOL and/or BOL between lastc and c? */
706 flagch = '\0';
707 i = 0;
708 if ((lastc == '\n' && m->g->cflags®_NEWLINE) ||
709 (lastc == OUT && !(m->eflags®_NOTBOL))) {
710 flagch = BOL;
711 i = m->g->nbol;
712 }
713 if ((c == '\n' && m->g->cflags®_NEWLINE) ||
714 (c == OUT && !(m->eflags®_NOTEOL)) ) {
715 flagch = (flagch == BOL) ? BOLEOL : EOL;
716 i += m->g->neol;
717 }
718 if (i != 0) {
719 for (; i > 0; i--)
720 st = step(m->g, startst, stopst,
721 st, flagch, st);
722 SP("boleol", st, c);
723 }
724
725 /* how about a word boundary? */
726 if ((flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
727 (c != OUT && ISWORD(c)))
728 flagch = BOW;
729 if ((lastc != OUT && ISWORD(lastc)) &&
730 (flagch == EOL || (c != OUT && !ISWORD(c))))
731 flagch = EOW;
732 if (flagch == BOW || flagch == EOW) {
733 st = step(m->g, startst, stopst, st, flagch, st);
734 SP("boweow", st, c);
735 }
736
737 /* are we done? */
738 if (ISSET(st, stopst) || p == stop)
739 break; /* NOTE BREAK OUT */
740
741 /* no, we must deal with this character */
742 ASSIGN(tmp, st);
743 ASSIGN(st, fresh);
744 assert(c != OUT);
745 st = step(m->g, startst, stopst, tmp, c, st);
746 SP("aft", st, c);
747 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
748 p++;
749 }
750
751 assert(coldp != NULL);
752 m->coldp = coldp;
753 if (ISSET(st, stopst))
754 return(p+1);
755 else
756 return(NULL);
757 }
758
759 /*
760 - slow - step through the string more deliberately
761 */
762 static const char * /* where it ended */
slow(struct match * m,const char * start,const char * stop,sopno startst,sopno stopst)763 slow(struct match *m, const char *start, const char *stop, sopno startst,
764 sopno stopst)
765 {
766 states st = m->st;
767 states empty = m->empty;
768 states tmp = m->tmp;
769 const char *p = start;
770 int c;
771 int lastc; /* previous c */
772 int flagch;
773 int i;
774 const char *matchp; /* last p at which a match ended */
775
776 if (start == m->offp || (start == m->beginp && !(m->eflags®_NOTBOL)))
777 c = OUT;
778 else
779 c = *(start-1);
780
781 AT("slow", start, stop, startst, stopst);
782 CLEAR(st);
783 SET1(st, startst);
784 SP("sstart", st, *p);
785 st = step(m->g, startst, stopst, st, NOTHING, st);
786 matchp = NULL;
787 for (;;) {
788 /* next character */
789 lastc = c;
790 c = (p == m->endp) ? OUT : *p;
791
792 /* is there an EOL and/or BOL between lastc and c? */
793 flagch = '\0';
794 i = 0;
795 if ((lastc == '\n' && m->g->cflags®_NEWLINE) ||
796 (lastc == OUT && !(m->eflags®_NOTBOL))) {
797 flagch = BOL;
798 i = m->g->nbol;
799 }
800 if ((c == '\n' && m->g->cflags®_NEWLINE) ||
801 (c == OUT && !(m->eflags®_NOTEOL))) {
802 flagch = (flagch == BOL) ? BOLEOL : EOL;
803 i += m->g->neol;
804 }
805 if (i != 0) {
806 for (; i > 0; i--)
807 st = step(m->g, startst, stopst,
808 st, flagch, st);
809 SP("sboleol", st, c);
810 }
811
812 /* how about a word boundary? */
813 if ((flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
814 (c != OUT && ISWORD(c)))
815 flagch = BOW;
816 if ((lastc != OUT && ISWORD(lastc)) &&
817 (flagch == EOL || (c != OUT && !ISWORD(c))))
818 flagch = EOW;
819 if (flagch == BOW || flagch == EOW) {
820 st = step(m->g, startst, stopst, st, flagch, st);
821 SP("sboweow", st, c);
822 }
823
824 /* are we done? */
825 if (ISSET(st, stopst))
826 matchp = p;
827 if (EQ(st, empty) || p == stop)
828 break; /* NOTE BREAK OUT */
829
830 /* no, we must deal with this character */
831 ASSIGN(tmp, st);
832 ASSIGN(st, empty);
833 assert(c != OUT);
834 st = step(m->g, startst, stopst, tmp, c, st);
835 SP("saft", st, c);
836 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
837 p++;
838 }
839
840 return(matchp);
841 }
842
843
844 /*
845 - step - map set of states reachable before char to set reachable after
846 */
847 static states
step(struct re_guts * g,sopno start,sopno stop,states bef,int ch,states aft)848 step(struct re_guts *g,
849 sopno start, /* start state within strip */
850 sopno stop, /* state after stop state within strip */
851 states bef, /* states reachable before */
852 int ch, /* character or NONCHAR code */
853 states aft) /* states already known reachable after */
854 {
855 cset *cs;
856 sop s;
857 sopno pc;
858 onestate here; /* note, macros know this name */
859 sopno look;
860 int i;
861
862 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
863 s = g->strip[pc];
864 switch (OP(s)) {
865 case OEND:
866 assert(pc == stop-1);
867 break;
868 case OCHAR:
869 /* only characters can match */
870 assert(!NONCHAR(ch) || ch != (char)OPND(s));
871 if (ch == (char)OPND(s))
872 FWD(aft, bef, 1);
873 break;
874 case OBOL:
875 if (ch == BOL || ch == BOLEOL)
876 FWD(aft, bef, 1);
877 break;
878 case OEOL:
879 if (ch == EOL || ch == BOLEOL)
880 FWD(aft, bef, 1);
881 break;
882 case OBOW:
883 if (ch == BOW)
884 FWD(aft, bef, 1);
885 break;
886 case OEOW:
887 if (ch == EOW)
888 FWD(aft, bef, 1);
889 break;
890 case OANY:
891 if (!NONCHAR(ch))
892 FWD(aft, bef, 1);
893 break;
894 case OANYOF:
895 cs = &g->sets[OPND(s)];
896 if (!NONCHAR(ch) && CHIN(cs, ch))
897 FWD(aft, bef, 1);
898 break;
899 case OBACK_: /* ignored here */
900 case O_BACK:
901 FWD(aft, aft, 1);
902 break;
903 case OPLUS_: /* forward, this is just an empty */
904 FWD(aft, aft, 1);
905 break;
906 case O_PLUS: /* both forward and back */
907 FWD(aft, aft, 1);
908 i = ISSETBACK(aft, OPND(s));
909 BACK(aft, aft, OPND(s));
910 if (!i && ISSETBACK(aft, OPND(s))) {
911 /* oho, must reconsider loop body */
912 pc -= OPND(s) + 1;
913 INIT(here, pc);
914 }
915 break;
916 case OQUEST_: /* two branches, both forward */
917 FWD(aft, aft, 1);
918 FWD(aft, aft, OPND(s));
919 break;
920 case O_QUEST: /* just an empty */
921 FWD(aft, aft, 1);
922 break;
923 case OLPAREN: /* not significant here */
924 case ORPAREN:
925 FWD(aft, aft, 1);
926 break;
927 case OCH_: /* mark the first two branches */
928 FWD(aft, aft, 1);
929 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
930 FWD(aft, aft, OPND(s));
931 break;
932 case OOR1: /* done a branch, find the O_CH */
933 if (ISSTATEIN(aft, here)) {
934 for (look = 1;
935 OP(s = g->strip[pc+look]) != O_CH;
936 look += OPND(s))
937 assert(OP(s) == OOR2);
938 FWD(aft, aft, look + 1);
939 }
940 break;
941 case OOR2: /* propagate OCH_'s marking */
942 FWD(aft, aft, 1);
943 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
944 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
945 FWD(aft, aft, OPND(s));
946 }
947 break;
948 case O_CH: /* just empty */
949 FWD(aft, aft, 1);
950 break;
951 default: /* ooooops... */
952 assert(nope);
953 break;
954 }
955 }
956
957 return(aft);
958 }
959
960 #ifdef REDEBUG
961 /*
962 - print - print a set of states
963 */
964 static void
print(struct match * m,const char * caption,states st,int ch,FILE * d)965 print(struct match *m, const char *caption, states st, int ch, FILE *d)
966 {
967 struct re_guts *g = m->g;
968 int i;
969 int first = 1;
970
971 if (!(m->eflags®_TRACE))
972 return;
973
974 (void)fprintf(d, "%s", caption);
975 (void)fprintf(d, " %s", pchar(ch));
976 for (i = 0; i < g->nstates; i++) {
977 if (ISSET(st, i)) {
978 (void)fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
979 first = 0;
980 }
981 }
982 (void)fprintf(d, "\n");
983 }
984
985 /*
986 - at - print current situation
987 */
988 static void
at(struct match * m,const char * title,const char * start,const char * stop,sopno startst,sopno stopst)989 at(struct match *m, const char *title, const char *start, const char *stop,
990 sopno startst, sopno stopst)
991 {
992 if (!(m->eflags®_TRACE))
993 return;
994
995 (void)printf("%s %s-", title, pchar(*start));
996 (void)printf("%s ", pchar(*stop));
997 (void)printf("%ld-%ld\n", (long)startst, (long)stopst);
998 }
999
1000 #ifndef PCHARDONE
1001 #define PCHARDONE /* never again */
1002 static const char *nonchars[] =
1003 { "OUT", "BOL", "EOL", "BOLEOL", "NOTHING", "BOW", "EOW" };
1004 #define PNONCHAR(c) \
1005 ((c) - OUT < (sizeof(nonchars)/sizeof(nonchars[0])) \
1006 ? nonchars[(c) - OUT] : "invalid")
1007
1008 /*
1009 - pchar - make a character printable
1010 *
1011 * Is this identical to regchar() over in debug.c? Well, yes. But a
1012 * duplicate here avoids having a debugging-capable regexec.o tied to
1013 * a matching debug.o, and this is convenient. It all disappears in
1014 * the non-debug compilation anyway, so it doesn't matter much.
1015 */
1016 static const char * /* -> representation */
pchar(int ch)1017 pchar(int ch)
1018 {
1019 static char pbuf[10];
1020
1021 if (NONCHAR(ch)) {
1022 if (ch - OUT < (sizeof(nonchars)/sizeof(nonchars[0])))
1023 return nonchars[ch - OUT];
1024 return "invalid";
1025 }
1026 if (isprint((unsigned char)ch) || ch == ' ')
1027 (void)snprintf(pbuf, sizeof pbuf, "%c", ch);
1028 else
1029 (void)snprintf(pbuf, sizeof pbuf, "\\%o", ch);
1030 return(pbuf);
1031 }
1032 #endif
1033 #endif
1034
1035 #undef matcher
1036 #undef fast
1037 #undef slow
1038 #undef dissect
1039 #undef backref
1040 #undef step
1041 #undef print
1042 #undef at
1043 #undef match
1044 #undef nope
1045