1 /* $OpenBSD: engine.c,v 1.15 2005/08/05 13:03:00 espie 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 char *offp; /* offsets work from here */
76 char *beginp; /* start of string -- virtual NUL precedes */
77 char *endp; /* end of string -- virtual NUL here */
78 char *coldp; /* can be no match starting before here */
79 char **lastpos; /* [nplus+1] */
80 STATEVARS;
81 states st; /* current states */
82 states fresh; /* states for a fresh start */
83 states tmp; /* temporary */
84 states empty; /* empty set of states */
85 };
86
87 static int matcher(struct re_guts *, char *, size_t, regmatch_t[], int);
88 static char *dissect(struct match *, char *, char *, sopno, sopno);
89 static char *backref(struct match *, char *, char *, sopno, sopno, sopno, int);
90 static char *fast(struct match *, char *, char *, sopno, sopno);
91 static char *slow(struct match *, char *, char *, sopno, sopno);
92 static states step(struct re_guts *, sopno, sopno, states, int, states);
93 #define MAX_RECURSION 100
94 #define BOL (OUT+1)
95 #define EOL (BOL+1)
96 #define BOLEOL (BOL+2)
97 #define NOTHING (BOL+3)
98 #define BOW (BOL+4)
99 #define EOW (BOL+5)
100 #define CODEMAX (BOL+5) /* highest code used */
101 #define NONCHAR(c) ((c) > CHAR_MAX)
102 #define NNONCHAR (CODEMAX-CHAR_MAX)
103 #ifdef REDEBUG
104 static void print(struct match *, char *, states, int, FILE *);
105 #endif
106 #ifdef REDEBUG
107 static void at(struct match *, char *, char *, char *, sopno, sopno);
108 #endif
109 #ifdef REDEBUG
110 static char *pchar(int);
111 #endif
112
113 #ifdef REDEBUG
114 #define SP(t, s, c) print(m, t, s, c, stdout)
115 #define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
116 #define NOTE(str) { if (m->eflags®_TRACE) (void)printf("=%s\n", (str)); }
117 static int nope = 0;
118 #else
119 #define SP(t, s, c) /* nothing */
120 #define AT(t, p1, p2, s1, s2) /* nothing */
121 #define NOTE(s) /* nothing */
122 #endif
123
124 /*
125 - matcher - the actual matching engine
126 */
127 static int /* 0 success, REG_NOMATCH failure */
matcher(struct re_guts * g,char * string,size_t nmatch,regmatch_t pmatch[],int eflags)128 matcher(struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[],
129 int eflags)
130 {
131 char *endp;
132 int i;
133 struct match mv;
134 struct match *m = &mv;
135 char *dp;
136 const sopno gf = g->firststate+1; /* +1 for OEND */
137 const sopno gl = g->laststate;
138 char *start;
139 char *stop;
140
141 /* simplify the situation where possible */
142 if (g->cflags®_NOSUB)
143 nmatch = 0;
144 if (eflags®_STARTEND) {
145 start = string + pmatch[0].rm_so;
146 stop = string + pmatch[0].rm_eo;
147 } else {
148 start = string;
149 stop = start + strlen(start);
150 }
151 if (stop < start)
152 return(REG_INVARG);
153
154 /* prescreening; this does wonders for this rather slow code */
155 if (g->must != NULL) {
156 for (dp = start; dp < stop; dp++)
157 if (*dp == g->must[0] && stop - dp >= g->mlen &&
158 memcmp(dp, g->must, (size_t)g->mlen) == 0)
159 break;
160 if (dp == stop) /* we didn't find g->must */
161 return(REG_NOMATCH);
162 }
163
164 /* match struct setup */
165 m->g = g;
166 m->eflags = eflags;
167 m->pmatch = NULL;
168 m->lastpos = NULL;
169 m->offp = string;
170 m->beginp = start;
171 m->endp = (char*)stop;
172 STATESETUP(m, 4);
173 SETUP(m->st);
174 SETUP(m->fresh);
175 SETUP(m->tmp);
176 SETUP(m->empty);
177 CLEAR(m->empty);
178
179 /* this loop does only one repetition except for backrefs */
180 for (;;) {
181 endp = fast(m, start, stop, gf, gl);
182 if (endp == NULL) { /* a miss */
183 free(m->pmatch);
184 free(m->lastpos);
185 STATETEARDOWN(m);
186 return(REG_NOMATCH);
187 }
188 if (nmatch == 0 && !g->backrefs)
189 break; /* no further info needed */
190
191 /* where? */
192 assert(m->coldp != NULL);
193 for (;;) {
194 NOTE("finding start");
195 endp = slow(m, m->coldp, stop, gf, gl);
196 if (endp != NULL)
197 break;
198 assert(m->coldp < m->endp);
199 m->coldp++;
200 }
201 if (nmatch == 1 && !g->backrefs)
202 break; /* no further info needed */
203
204 /* oh my, he wants the subexpressions... */
205 if (m->pmatch == NULL)
206 m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
207 sizeof(regmatch_t));
208 if (m->pmatch == NULL) {
209 STATETEARDOWN(m);
210 return(REG_ESPACE);
211 }
212 for (i = 1; i <= (int)m->g->nsub; i++)
213 m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
214 if (!g->backrefs && !(m->eflags®_BACKR)) {
215 NOTE("dissecting");
216 dp = dissect(m, m->coldp, endp, gf, gl);
217 } else {
218 if (g->nplus > 0 && m->lastpos == NULL)
219 m->lastpos = (char **)malloc((g->nplus+1) *
220 sizeof(char *));
221 if (g->nplus > 0 && m->lastpos == NULL) {
222 free(m->pmatch);
223 STATETEARDOWN(m);
224 return(REG_ESPACE);
225 }
226 NOTE("backref dissect");
227 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
228 }
229 if (dp != NULL)
230 break;
231
232 /* uh-oh... we couldn't find a subexpression-level match */
233 assert(g->backrefs); /* must be back references doing it */
234 assert(g->nplus == 0 || m->lastpos != NULL);
235 for (;;) {
236 if (dp != NULL || endp <= m->coldp)
237 break; /* defeat */
238 NOTE("backoff");
239 endp = slow(m, m->coldp, endp-1, gf, gl);
240 if (endp == NULL)
241 break; /* defeat */
242 /* try it on a shorter possibility */
243 #ifndef NDEBUG
244 for (i = 1; i <= m->g->nsub; i++) {
245 assert(m->pmatch[i].rm_so == -1);
246 assert(m->pmatch[i].rm_eo == -1);
247 }
248 #endif
249 NOTE("backoff dissect");
250 dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
251 }
252 assert(dp == NULL || dp == endp);
253 if (dp != NULL) /* found a shorter one */
254 break;
255
256 /* despite initial appearances, there is no match here */
257 NOTE("false alarm");
258 if (m->coldp == stop)
259 break;
260 start = m->coldp + 1; /* recycle starting later */
261 }
262
263 /* fill in the details if requested */
264 if (nmatch > 0) {
265 pmatch[0].rm_so = m->coldp - m->offp;
266 pmatch[0].rm_eo = endp - m->offp;
267 }
268 if (nmatch > 1) {
269 assert(m->pmatch != NULL);
270 for (i = 1; i < (ssize_t)nmatch; i++)
271 if (i <= (int)m->g->nsub)
272 pmatch[i] = m->pmatch[i];
273 else {
274 pmatch[i].rm_so = -1;
275 pmatch[i].rm_eo = -1;
276 }
277 }
278
279 if (m->pmatch != NULL)
280 free((char *)m->pmatch);
281 if (m->lastpos != NULL)
282 free((char *)m->lastpos);
283 STATETEARDOWN(m);
284 return(0);
285 }
286
287 /*
288 - dissect - figure out what matched what, no back references
289 */
290 static char * /* == stop (success) always */
dissect(struct match * m,char * start,char * stop,sopno startst,sopno stopst)291 dissect(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
292 {
293 int i;
294 sopno ss; /* start sop of current subRE */
295 sopno es; /* end sop of current subRE */
296 char *sp; /* start of string matched by it */
297 char *stp; /* string matched by it cannot pass here */
298 char *rest; /* start of rest of string */
299 char *tail; /* string unmatched by rest of RE */
300 sopno ssub; /* start sop of subsubRE */
301 sopno esub; /* end sop of subsubRE */
302 char *ssp; /* start of string matched by subsubRE */
303 char *sep; /* end of string matched by subsubRE */
304 char *oldssp; /* previous ssp */
305
306 AT("diss", start, stop, startst, stopst);
307 sp = start;
308 for (ss = startst; ss < stopst; ss = es) {
309 /* identify end of subRE */
310 es = ss;
311 switch (OP(m->g->strip[es])) {
312 case OPLUS_:
313 case OQUEST_:
314 es += OPND(m->g->strip[es]);
315 break;
316 case OCH_:
317 while (OP(m->g->strip[es]) != O_CH)
318 es += OPND(m->g->strip[es]);
319 break;
320 }
321 es++;
322
323 /* figure out what it matched */
324 switch (OP(m->g->strip[ss])) {
325 case OEND:
326 assert(nope);
327 break;
328 case OCHAR:
329 sp++;
330 break;
331 case OBOL:
332 case OEOL:
333 case OBOW:
334 case OEOW:
335 break;
336 case OANY:
337 case OANYOF:
338 sp++;
339 break;
340 case OBACK_:
341 case O_BACK:
342 assert(nope);
343 break;
344 /* cases where length of match is hard to find */
345 case OQUEST_:
346 stp = stop;
347 for (;;) {
348 /* how long could this one be? */
349 rest = slow(m, sp, stp, ss, es);
350 assert(rest != NULL); /* it did match */
351 /* could the rest match the rest? */
352 tail = slow(m, rest, stop, es, stopst);
353 if (tail == stop)
354 break; /* yes! */
355 /* no -- try a shorter match for this one */
356 stp = rest - 1;
357 assert(stp >= sp); /* it did work */
358 }
359 ssub = ss + 1;
360 esub = es - 1;
361 /* did innards match? */
362 if (slow(m, sp, rest, ssub, esub) != NULL) {
363 if (dissect(m, sp, rest, ssub, esub) != rest) {
364 assert(0 && "dissect(...) should return rest");
365 }
366 } else /* no */
367 assert(sp == rest);
368 sp = rest;
369 break;
370 case OPLUS_:
371 stp = stop;
372 for (;;) {
373 /* how long could this one be? */
374 rest = slow(m, sp, stp, ss, es);
375 assert(rest != NULL); /* it did match */
376 /* could the rest match the rest? */
377 tail = slow(m, rest, stop, es, stopst);
378 if (tail == stop)
379 break; /* yes! */
380 /* no -- try a shorter match for this one */
381 stp = rest - 1;
382 assert(stp >= sp); /* it did work */
383 }
384 ssub = ss + 1;
385 esub = es - 1;
386 ssp = sp;
387 oldssp = ssp;
388 for (;;) { /* find last match of innards */
389 sep = slow(m, ssp, rest, ssub, esub);
390 if (sep == NULL || sep == ssp)
391 break; /* failed or matched null */
392 oldssp = ssp; /* on to next try */
393 ssp = sep;
394 }
395 if (sep == NULL) {
396 /* last successful match */
397 sep = ssp;
398 ssp = oldssp;
399 }
400 assert(sep == rest); /* must exhaust substring */
401 assert(slow(m, ssp, sep, ssub, esub) == rest);
402 if (dissect(m, ssp, sep, ssub, esub) != sep) {
403 assert(0 && "dissect(...) should return sep");
404 }
405 sp = rest;
406 break;
407 case OCH_:
408 stp = stop;
409 for (;;) {
410 /* how long could this one be? */
411 rest = slow(m, sp, stp, ss, es);
412 assert(rest != NULL); /* it did match */
413 /* could the rest match the rest? */
414 tail = slow(m, rest, stop, es, stopst);
415 if (tail == stop)
416 break; /* yes! */
417 /* no -- try a shorter match for this one */
418 stp = rest - 1;
419 assert(stp >= sp); /* it did work */
420 }
421 ssub = ss + 1;
422 esub = ss + OPND(m->g->strip[ss]) - 1;
423 assert(OP(m->g->strip[esub]) == OOR1);
424 for (;;) { /* find first matching branch */
425 if (slow(m, sp, rest, ssub, esub) == rest)
426 break; /* it matched all of it */
427 /* that one missed, try next one */
428 assert(OP(m->g->strip[esub]) == OOR1);
429 esub++;
430 assert(OP(m->g->strip[esub]) == OOR2);
431 ssub = esub + 1;
432 esub += OPND(m->g->strip[esub]);
433 if (OP(m->g->strip[esub]) == OOR2)
434 esub--;
435 else
436 assert(OP(m->g->strip[esub]) == O_CH);
437 }
438 if (dissect(m, sp, rest, ssub, esub) != rest) {
439 assert(0 && "dissect(...) should return rest");
440 }
441 sp = rest;
442 break;
443 case O_PLUS:
444 case O_QUEST:
445 case OOR1:
446 case OOR2:
447 case O_CH:
448 assert(nope);
449 break;
450 case OLPAREN:
451 i = OPND(m->g->strip[ss]);
452 assert(0 < i && i <= m->g->nsub);
453 m->pmatch[i].rm_so = sp - m->offp;
454 break;
455 case ORPAREN:
456 i = OPND(m->g->strip[ss]);
457 assert(0 < i && i <= m->g->nsub);
458 m->pmatch[i].rm_eo = sp - m->offp;
459 break;
460 default: /* uh oh */
461 assert(nope);
462 break;
463 }
464 }
465
466 assert(sp == stop);
467 return(sp);
468 }
469
470 /*
471 - backref - figure out what matched what, figuring in back references
472 */
473 static char * /* == stop (success) or NULL (failure) */
backref(struct match * m,char * start,char * stop,sopno startst,sopno stopst,sopno lev,int rec)474 backref(struct match *m, char *start, char *stop, sopno startst, sopno stopst,
475 sopno lev, int rec) /* PLUS nesting level */
476 {
477 int i;
478 sopno ss; /* start sop of current subRE */
479 char *sp; /* start of string matched by it */
480 sopno ssub; /* start sop of subsubRE */
481 sopno esub; /* end sop of subsubRE */
482 char *ssp; /* start of string matched by subsubRE */
483 char *dp;
484 size_t len;
485 int hard;
486 sop s;
487 regoff_t offsave;
488 cset *cs;
489
490 AT("back", start, stop, startst, stopst);
491 sp = start;
492
493 /* get as far as we can with easy stuff */
494 hard = 0;
495 for (ss = startst; !hard && ss < stopst; ss++)
496 switch (OP(s = m->g->strip[ss])) {
497 case OCHAR:
498 if (sp == stop || *sp++ != (char)OPND(s))
499 return(NULL);
500 break;
501 case OANY:
502 if (sp == stop)
503 return(NULL);
504 sp++;
505 break;
506 case OANYOF:
507 cs = &m->g->sets[OPND(s)];
508 if (sp == stop || !CHIN(cs, *sp++))
509 return(NULL);
510 break;
511 case OBOL:
512 if ( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
513 (sp < m->endp && *(sp-1) == '\n' &&
514 (m->g->cflags®_NEWLINE)) )
515 { /* yes */ }
516 else
517 return(NULL);
518 break;
519 case OEOL:
520 if ( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
521 (sp < m->endp && *sp == '\n' &&
522 (m->g->cflags®_NEWLINE)) )
523 { /* yes */ }
524 else
525 return(NULL);
526 break;
527 case OBOW:
528 if (( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
529 (sp < m->endp && *(sp-1) == '\n' &&
530 (m->g->cflags®_NEWLINE)) ||
531 (sp > m->beginp &&
532 !ISWORD(*(sp-1))) ) &&
533 (sp < m->endp && ISWORD(*sp)) )
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 0;
668 }
669
670 /*
671 - fast - step through the string at top speed
672 */
673 static char * /* where tentative match ended, or NULL */
fast(struct match * m,char * start,char * stop,sopno startst,sopno stopst)674 fast(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
675 {
676 states st = m->st;
677 states fresh = m->fresh;
678 states tmp = m->tmp;
679 char *p = start;
680 int c = (start == m->beginp) ? OUT : *(start-1);
681 int lastc; /* previous c */
682 int flagch;
683 int i;
684 char *coldp; /* last p after which no match was underway */
685
686 CLEAR(st);
687 SET1(st, startst);
688 st = step(m->g, startst, stopst, st, NOTHING, st);
689 ASSIGN(fresh, st);
690 SP("start", st, *p);
691 coldp = NULL;
692 for (;;) {
693 /* next character */
694 lastc = c;
695 c = (p == m->endp) ? OUT : *p;
696 if (EQ(st, fresh))
697 coldp = p;
698
699 /* is there an EOL and/or BOL between lastc and c? */
700 flagch = '\0';
701 i = 0;
702 if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
703 (lastc == OUT && !(m->eflags®_NOTBOL)) ) {
704 flagch = BOL;
705 i = m->g->nbol;
706 }
707 if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
708 (c == OUT && !(m->eflags®_NOTEOL)) ) {
709 flagch = (flagch == BOL) ? BOLEOL : EOL;
710 i += m->g->neol;
711 }
712 if (i != 0) {
713 for (; i > 0; i--)
714 st = step(m->g, startst, stopst, st, flagch, st);
715 SP("boleol", st, c);
716 }
717
718 /* how about a word boundary? */
719 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
720 (c != OUT && ISWORD(c)) ) {
721 flagch = BOW;
722 }
723 if ( (lastc != OUT && ISWORD(lastc)) &&
724 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
725 flagch = EOW;
726 }
727 if (flagch == BOW || flagch == EOW) {
728 st = step(m->g, startst, stopst, st, flagch, st);
729 SP("boweow", st, c);
730 }
731
732 /* are we done? */
733 if (ISSET(st, stopst) || p == stop)
734 break; /* NOTE BREAK OUT */
735
736 /* no, we must deal with this character */
737 ASSIGN(tmp, st);
738 ASSIGN(st, fresh);
739 assert(c != OUT);
740 st = step(m->g, startst, stopst, tmp, c, st);
741 SP("aft", st, c);
742 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
743 p++;
744 }
745
746 assert(coldp != NULL);
747 m->coldp = coldp;
748 if (ISSET(st, stopst))
749 return(p+1);
750 else
751 return(NULL);
752 }
753
754 /*
755 - slow - step through the string more deliberately
756 */
757 static char * /* where it ended */
slow(struct match * m,char * start,char * stop,sopno startst,sopno stopst)758 slow(struct match *m, char *start, char *stop, sopno startst, sopno stopst)
759 {
760 states st = m->st;
761 states empty = m->empty;
762 states tmp = m->tmp;
763 char *p = start;
764 int c = (start == m->beginp) ? OUT : *(start-1);
765 int lastc; /* previous c */
766 int flagch;
767 int i;
768 char *matchp; /* last p at which a match ended */
769
770 AT("slow", start, stop, startst, stopst);
771 CLEAR(st);
772 SET1(st, startst);
773 SP("sstart", st, *p);
774 st = step(m->g, startst, stopst, st, NOTHING, st);
775 matchp = NULL;
776 for (;;) {
777 /* next character */
778 lastc = c;
779 c = (p == m->endp) ? OUT : *p;
780
781 /* is there an EOL and/or BOL between lastc and c? */
782 flagch = '\0';
783 i = 0;
784 if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
785 (lastc == OUT && !(m->eflags®_NOTBOL)) ) {
786 flagch = BOL;
787 i = m->g->nbol;
788 }
789 if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
790 (c == OUT && !(m->eflags®_NOTEOL)) ) {
791 flagch = (flagch == BOL) ? BOLEOL : EOL;
792 i += m->g->neol;
793 }
794 if (i != 0) {
795 for (; i > 0; i--)
796 st = step(m->g, startst, stopst, st, flagch, st);
797 SP("sboleol", st, c);
798 }
799
800 /* how about a word boundary? */
801 if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
802 (c != OUT && ISWORD(c)) ) {
803 flagch = BOW;
804 }
805 if ( (lastc != OUT && ISWORD(lastc)) &&
806 (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
807 flagch = EOW;
808 }
809 if (flagch == BOW || flagch == EOW) {
810 st = step(m->g, startst, stopst, st, flagch, st);
811 SP("sboweow", st, c);
812 }
813
814 /* are we done? */
815 if (ISSET(st, stopst))
816 matchp = p;
817 if (EQ(st, empty) || p == stop)
818 break; /* NOTE BREAK OUT */
819
820 /* no, we must deal with this character */
821 ASSIGN(tmp, st);
822 ASSIGN(st, empty);
823 assert(c != OUT);
824 st = step(m->g, startst, stopst, tmp, c, st);
825 SP("saft", st, c);
826 assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
827 p++;
828 }
829
830 return(matchp);
831 }
832
833
834 /*
835 - step - map set of states reachable before char to set reachable after
836 */
837 static states
step(struct re_guts * g,sopno start,sopno stop,states bef,int ch,states aft)838 step(struct re_guts *g,
839 sopno start, /* start state within strip */
840 sopno stop, /* state after stop state within strip */
841 states bef, /* states reachable before */
842 int ch, /* character or NONCHAR code */
843 states aft) /* states already known reachable after */
844 {
845 cset *cs;
846 sop s;
847 sopno pc;
848 onestate here; /* note, macros know this name */
849 sopno look;
850 int i;
851
852 for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
853 s = g->strip[pc];
854 switch (OP(s)) {
855 case OEND:
856 assert(pc == stop-1);
857 break;
858 case OCHAR:
859 /* only characters can match */
860 assert(!NONCHAR(ch) || ch != (char)OPND(s));
861 if (ch == (char)OPND(s))
862 FWD(aft, bef, 1);
863 break;
864 case OBOL:
865 if (ch == BOL || ch == BOLEOL)
866 FWD(aft, bef, 1);
867 break;
868 case OEOL:
869 if (ch == EOL || ch == BOLEOL)
870 FWD(aft, bef, 1);
871 break;
872 case OBOW:
873 if (ch == BOW)
874 FWD(aft, bef, 1);
875 break;
876 case OEOW:
877 if (ch == EOW)
878 FWD(aft, bef, 1);
879 break;
880 case OANY:
881 if (!NONCHAR(ch))
882 FWD(aft, bef, 1);
883 break;
884 case OANYOF:
885 cs = &g->sets[OPND(s)];
886 if (!NONCHAR(ch) && CHIN(cs, ch))
887 FWD(aft, bef, 1);
888 break;
889 case OBACK_: /* ignored here */
890 case O_BACK:
891 FWD(aft, aft, 1);
892 break;
893 case OPLUS_: /* forward, this is just an empty */
894 FWD(aft, aft, 1);
895 break;
896 case O_PLUS: /* both forward and back */
897 FWD(aft, aft, 1);
898 i = ISSETBACK(aft, OPND(s));
899 BACK(aft, aft, OPND(s));
900 if (!i && ISSETBACK(aft, OPND(s))) {
901 /* oho, must reconsider loop body */
902 pc -= OPND(s) + 1;
903 INIT(here, pc);
904 }
905 break;
906 case OQUEST_: /* two branches, both forward */
907 FWD(aft, aft, 1);
908 FWD(aft, aft, OPND(s));
909 break;
910 case O_QUEST: /* just an empty */
911 FWD(aft, aft, 1);
912 break;
913 case OLPAREN: /* not significant here */
914 case ORPAREN:
915 FWD(aft, aft, 1);
916 break;
917 case OCH_: /* mark the first two branches */
918 FWD(aft, aft, 1);
919 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
920 FWD(aft, aft, OPND(s));
921 break;
922 case OOR1: /* done a branch, find the O_CH */
923 if (ISSTATEIN(aft, here)) {
924 for (look = 1;
925 OP(s = g->strip[pc+look]) != O_CH;
926 look += OPND(s))
927 assert(OP(s) == OOR2);
928 FWD(aft, aft, look);
929 }
930 break;
931 case OOR2: /* propagate OCH_'s marking */
932 FWD(aft, aft, 1);
933 if (OP(g->strip[pc+OPND(s)]) != O_CH) {
934 assert(OP(g->strip[pc+OPND(s)]) == OOR2);
935 FWD(aft, aft, OPND(s));
936 }
937 break;
938 case O_CH: /* just empty */
939 FWD(aft, aft, 1);
940 break;
941 default: /* ooooops... */
942 assert(nope);
943 break;
944 }
945 }
946
947 return(aft);
948 }
949
950 #ifdef REDEBUG
951 /*
952 - print - print a set of states
953 */
954 static void
print(struct match * m,char * caption,states st,int ch,FILE * d)955 print(struct match *m, char *caption, states st, int ch, FILE *d)
956 {
957 struct re_guts *g = m->g;
958 int i;
959 int first = 1;
960
961 if (!(m->eflags®_TRACE))
962 return;
963
964 (void)fprintf(d, "%s", caption);
965 if (ch != '\0')
966 (void)fprintf(d, " %s", pchar(ch));
967 for (i = 0; i < g->nstates; i++)
968 if (ISSET(st, i)) {
969 (void)fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
970 first = 0;
971 }
972 (void)fprintf(d, "\n");
973 }
974
975 /*
976 - at - print current situation
977 */
978 static void
at(struct match * m,char * title,char * start,char * stop,sopno startst,sopno stopst)979 at(struct match *m, char *title, char *start, char *stop, sopno startst,
980 sopno stopst)
981 {
982 if (!(m->eflags®_TRACE))
983 return;
984
985 (void)printf("%s %s-", title, pchar(*start));
986 (void)printf("%s ", pchar(*stop));
987 (void)printf("%ld-%ld\n", (long)startst, (long)stopst);
988 }
989
990 #ifndef PCHARDONE
991 #define PCHARDONE /* never again */
992 /*
993 - pchar - make a character printable
994 *
995 * Is this identical to regchar() over in debug.c? Well, yes. But a
996 * duplicate here avoids having a debugging-capable regexec.o tied to
997 * a matching debug.o, and this is convenient. It all disappears in
998 * the non-debug compilation anyway, so it doesn't matter much.
999 */
1000 static char * /* -> representation */
pchar(int ch)1001 pchar(int ch)
1002 {
1003 static char pbuf[10];
1004
1005 if (isprint(ch) || ch == ' ')
1006 (void)_snprintf(pbuf, sizeof pbuf, "%c", ch);
1007 else
1008 (void)_snprintf(pbuf, sizeof pbuf, "\\%o", ch);
1009 return(pbuf);
1010 }
1011 #endif
1012 #endif
1013
1014 #undef matcher
1015 #undef fast
1016 #undef slow
1017 #undef dissect
1018 #undef backref
1019 #undef step
1020 #undef print
1021 #undef at
1022 #undef match
1023 #undef nope
1024