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