1 #include <sys/types.h>
2 #include <stdio.h>
3 #include <string.h>
4 #include <ctype.h>
5 #include <limits.h>
6 #include <stdlib.h>
7 
8 /* local headers */
9 #include "regex.h"
10 #include "utils.h"
11 #include "regex2.h"
12 #include "cclass.h"
13 #include "cname.h"
14 
15 /*
16  * parse structure, passed up and down to avoid global variables and
17  * other clumsinesses
18  */
19 struct parse {
20 	char *next;		/* next character in RE */
21 	char *end;		/* end of string (-> NUL normally) */
22 	int error;		/* has an error been seen? */
23 	sop *strip;		/* malloced strip */
24 	sopno ssize;		/* malloced strip size (allocated) */
25 	sopno slen;		/* malloced strip length (used) */
26 	int ncsalloc;		/* number of csets allocated */
27 	struct re_guts *g;
28 #	define	NPAREN	10	/* we need to remember () 1-9 for back refs */
29 	sopno pbegin[NPAREN];	/* -> ( ([0] unused) */
30 	sopno pend[NPAREN];	/* -> ) ([0] unused) */
31 };
32 
33 /* #include "regcomp.ih" // why generate this */
34 /* forward references */
35 static void p_ere(register struct parse *p, int stop);
36 static void p_ere_exp(register struct parse *p);
37 static void p_str(register struct parse *p);
38 static void p_bre(register struct parse *p, register int end1, register int end2);
39 static int p_simp_re(register struct parse *p, int starordinary);
40 static int p_count(register struct parse *p);
41 static void p_bracket(register struct parse *p);
42 static void p_b_term(register struct parse *p, register cset *cs);
43 static void p_b_cclass(register struct parse *p, register cset *cs);
44 static void p_b_eclass(register struct parse *p, register cset *cs);
45 static char p_b_symbol(register struct parse *p);
46 static char p_b_coll_elem(register struct parse *p, int endc);
47 static char othercase(int ch);
48 static void bothcases(register struct parse *p, int ch);
49 static void ordinary(register struct parse *p, register int ch);
50 static void nonnewline(register struct parse *p);
51 static void repeat(register struct parse *p, sopno start, int from, int to);
52 static int seterr(register struct parse *p, int e);
53 static cset *allocset(register struct parse *p);
54 static void freeset(register struct parse *p, register cset *cs);
55 static int freezeset(register struct parse *p, register cset *cs);
56 static int firstch(register struct parse *p, register cset *cs);
57 static int nch(register struct parse *p, register cset *cs);
58 static void mcadd(register struct parse *p, register cset *cs, register char *cp);
59 static void mcsub(register cset *cs, register char *cp);
60 static int mcin(register cset *cs, register char *cp);
61 static char *mcfind(register cset *cs, register char *cp);
62 static void mcinvert(register struct parse *p, register cset *cs);
63 static void mccase(register struct parse *p, register cset *cs);
64 static int isinsets(register struct re_guts *g, int c);
65 static int samesets(register struct re_guts *g, int c1, int c2);
66 static void categorize(struct parse *p, register struct re_guts *g);
67 static sopno dupl(register struct parse *p, sopno start, sopno finish);
68 static void doemit(register struct parse *p, sop op, size_t opnd);
69 static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
70 static void dofwd(register struct parse *p, sopno pos, sop value);
71 static void enlarge(register struct parse *p, sopno size);
72 static void stripsnug(register struct parse *p, register struct re_guts *g);
73 static void findmust(register struct parse *p, register struct re_guts *g);
74 static sopno pluscount(register struct parse *p, register struct re_guts *g);
75 
76 static char nuls[10];		/* place to point scanner in event of error */
77 
78 /*
79  * macros for use with parse structure
80  * BEWARE:  these know that the parse structure is named `p' !!!
81  */
82 #define	PEEK()	(*p->next)
83 #define	PEEK2()	(*(p->next+1))
84 #define	MORE()	(p->next < p->end)
85 #define	MORE2()	(p->next+1 < p->end)
86 #define	SEE(c)	(MORE() && PEEK() == (c))
87 #define	SEETWO(a, b)	(MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
88 #define	EAT(c)	((SEE(c)) ? (NEXT(), 1) : 0)
89 #define	EATTWO(a, b)	((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
90 #define	NEXT()	(p->next++)
91 #define	NEXT2()	(p->next += 2)
92 #define	NEXTn(n)	(p->next += (n))
93 #define	GETNEXT()	(*p->next++)
94 #define	SETERROR(e)	seterr(p, (e))
95 #define	REQUIRE(co, e)	((co) || SETERROR(e))
96 #define	MUSTSEE(c, e)	(REQUIRE(MORE() && PEEK() == (c), e))
97 #define	MUSTEAT(c, e)	(REQUIRE(MORE() && GETNEXT() == (c), e))
98 #define	MUSTNOTSEE(c, e)	(REQUIRE(!MORE() || PEEK() != (c), e))
99 #define	EMIT(op, sopnd)	doemit(p, (sop)(op), (size_t)(sopnd))
100 #define	INSERT(op, pos)	doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
101 #define	AHEAD(pos)		dofwd(p, pos, HERE()-(pos))
102 #define	ASTERN(sop, pos)	EMIT(sop, HERE()-pos)
103 #define	HERE()		(p->slen)
104 #define	THERE()		(p->slen - 1)
105 #define	THERETHERE()	(p->slen - 2)
106 #define	DROP(n)	(p->slen -= (n))
107 
108 #ifndef NDEBUG
109 static int never = 0;		/* for use in asserts; shuts lint up */
110 #else
111 #define	never	0		/* some <assert.h>s have bugs too */
112 #endif
113 
114 /*
115  - regcomp - interface for parser and compilation
116  = extern int regcomp(regex_t *, const char *, int);
117  = #define	REG_BASIC	0000
118  = #define	REG_EXTENDED	0001
119  = #define	REG_ICASE	0002
120  = #define	REG_NOSUB	0004
121  = #define	REG_NEWLINE	0010
122  = #define	REG_NOSPEC	0020
123  = #define	REG_PEND	0040
124  = #define	REG_DUMP	0200
125  */
126 int				/* 0 success, otherwise REG_something */
regcomp(preg,pattern,cflags)127 regcomp(preg, pattern, cflags)
128 regex_t *preg;
129 const char *pattern;
130 int cflags;
131 {
132 	struct parse pa;
133 	register struct re_guts *g;
134 	register struct parse *p = &pa;
135 	register int i;
136 	register size_t len;
137 #ifdef REDEBUG
138 #	define	GOODFLAGS(f)	(f)
139 #else
140 #	define	GOODFLAGS(f)	((f)&~REG_DUMP)
141 #endif
142 
143 	cflags = GOODFLAGS(cflags);
144 	if ((cflags&REG_EXTENDED) && (cflags&REG_NOSPEC))
145 		return(REG_INVARG);
146 
147 	if (cflags&REG_PEND) {
148 		if (preg->re_endp < pattern)
149 			return(REG_INVARG);
150 		len = preg->re_endp - pattern;
151 	} else
152 		len = strlen((char *)pattern);
153 
154 	/* do the mallocs early so failure handling is easy */
155 	g = (struct re_guts *)malloc(sizeof(struct re_guts) +
156 							(NC-1)*sizeof(cat_t));
157 	if (g == NULL)
158 		return(REG_ESPACE);
159 	{
160 	  /* Patched for CERT Vulnerability Note VU#695940, Feb 2015. */
161 	  size_t new_ssize = len/(size_t)2*(size_t)3 + (size_t)1; /* ugh */
162 	  if (new_ssize < len || new_ssize > LONG_MAX / sizeof(sop)) {
163 	    free((char *) g);
164 	    return REG_INVARG;
165 	  }
166 	  p->ssize = new_ssize;
167 	}
168 	p->strip = (sop *)malloc(p->ssize * sizeof(sop));
169 	p->slen = 0;
170 	if (p->strip == NULL) {
171 		free((char *)g);
172 		return(REG_ESPACE);
173 	}
174 
175 	/* set things up */
176 	p->g = g;
177 	p->next = (char *)pattern;	/* convenience; we do not modify it */
178 	p->end = p->next + len;
179 	p->error = 0;
180 	p->ncsalloc = 0;
181 	for (i = 0; i < NPAREN; i++) {
182 		p->pbegin[i] = 0;
183 		p->pend[i] = 0;
184 	}
185 	g->csetsize = NC;
186 	g->sets = NULL;
187 	g->setbits = NULL;
188 	g->ncsets = 0;
189 	g->cflags = cflags;
190 	g->iflags = 0;
191 	g->nbol = 0;
192 	g->neol = 0;
193 	g->must = NULL;
194 	g->mlen = 0;
195 	g->nsub = 0;
196 	g->ncategories = 1;	/* category 0 is "everything else" */
197 	g->categories = &g->catspace[-(CHAR_MIN)];
198 	(void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
199 	g->backrefs = 0;
200 
201 	/* do it */
202 	EMIT(OEND, 0);
203 	g->firststate = THERE();
204 	if (cflags&REG_EXTENDED)
205 		p_ere(p, OUT);
206 	else if (cflags&REG_NOSPEC)
207 		p_str(p);
208 	else
209 		p_bre(p, OUT, OUT);
210 	EMIT(OEND, 0);
211 	g->laststate = THERE();
212 
213 	/* tidy up loose ends and fill things in */
214 	categorize(p, g);
215 	stripsnug(p, g);
216 	findmust(p, g);
217 	g->nplus = pluscount(p, g);
218 	g->magic = MAGIC2;
219 	preg->re_nsub = g->nsub;
220 	preg->re_g = g;
221 	preg->re_magic = MAGIC1;
222 #ifndef REDEBUG
223 	/* not debugging, so can't rely on the assert() in regexec() */
224 	if (g->iflags&BAD)
225 		SETERROR(REG_ASSERT);
226 #endif
227 
228 	/* win or lose, we're done */
229 	if (p->error != 0)	/* lose */
230 		regfree(preg);
231 	return(p->error);
232 }
233 
234 /*
235  - p_ere - ERE parser top level, concatenation and alternation
236  == static void p_ere(register struct parse *p, int stop);
237  */
238 static void
p_ere(p,stop)239 p_ere(p, stop)
240 register struct parse *p;
241 int stop;			/* character this ERE should end at */
242 {
243 	register char c;
244 	register sopno prevback;
245 	register sopno prevfwd;
246 	register sopno conc;
247 	register int first = 1;		/* is this the first alternative? */
248 
249 	for (;;) {
250 		/* do a bunch of concatenated expressions */
251 		conc = HERE();
252 		while (MORE() && (c = PEEK()) != '|' && c != stop)
253 			p_ere_exp(p);
254 		REQUIRE(HERE() != conc, REG_EMPTY);	/* require nonempty */
255 
256 		if (!EAT('|'))
257 			break;		/* NOTE BREAK OUT */
258 
259 		if (first) {
260 			INSERT(OCH_, conc);	/* offset is wrong */
261 			prevfwd = conc;
262 			prevback = conc;
263 			first = 0;
264 		}
265 		ASTERN(OOR1, prevback);
266 		prevback = THERE();
267 		AHEAD(prevfwd);			/* fix previous offset */
268 		prevfwd = HERE();
269 		EMIT(OOR2, 0);			/* offset is very wrong */
270 	}
271 
272 	if (!first) {		/* tail-end fixups */
273 		AHEAD(prevfwd);
274 		ASTERN(O_CH, prevback);
275 	}
276 
277 	assert(!MORE() || SEE(stop));
278 }
279 
280 /*
281  - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
282  == static void p_ere_exp(register struct parse *p);
283  */
284 static void
p_ere_exp(p)285 p_ere_exp(p)
286 register struct parse *p;
287 {
288 	register char c;
289 	register sopno pos;
290 	register int count;
291 	register int count2;
292 	register sopno subno;
293 	int wascaret = 0;
294 
295 	assert(MORE());		/* caller should have ensured this */
296 	c = GETNEXT();
297 
298 	pos = HERE();
299 	switch (c) {
300 	case '(':
301 		REQUIRE(MORE(), REG_EPAREN);
302 		p->g->nsub++;
303 		subno = p->g->nsub;
304 		if (subno < NPAREN)
305 			p->pbegin[subno] = HERE();
306 		EMIT(OLPAREN, subno);
307 		if (!SEE(')'))
308 			p_ere(p, ')');
309 		if (subno < NPAREN) {
310 			p->pend[subno] = HERE();
311 			assert(p->pend[subno] != 0);
312 		}
313 		EMIT(ORPAREN, subno);
314 		MUSTEAT(')', REG_EPAREN);
315 		break;
316 #ifndef POSIX_MISTAKE
317 	case ')':		/* happens only if no current unmatched ( */
318 		/*
319 		 * You may ask, why the ifndef?  Because I didn't notice
320 		 * this until slightly too late for 1003.2, and none of the
321 		 * other 1003.2 regular-expression reviewers noticed it at
322 		 * all.  So an unmatched ) is legal POSIX, at least until
323 		 * we can get it fixed.
324 		 */
325 		SETERROR(REG_EPAREN);
326 		break;
327 #endif
328 	case '^':
329 		EMIT(OBOL, 0);
330 		p->g->iflags |= USEBOL;
331 		p->g->nbol++;
332 		wascaret = 1;
333 		break;
334 	case '$':
335 		EMIT(OEOL, 0);
336 		p->g->iflags |= USEEOL;
337 		p->g->neol++;
338 		break;
339 	case '|':
340 		SETERROR(REG_EMPTY);
341 		break;
342 	case '*':
343 	case '+':
344 	case '?':
345 		SETERROR(REG_BADRPT);
346 		break;
347 	case '.':
348 		if (p->g->cflags&REG_NEWLINE)
349 			nonnewline(p);
350 		else
351 			EMIT(OANY, 0);
352 		break;
353 	case '[':
354 		p_bracket(p);
355 		break;
356 	case '\\':
357 		REQUIRE(MORE(), REG_EESCAPE);
358 		c = GETNEXT();
359 		ordinary(p, c);
360 		break;
361 	case '{':		/* okay as ordinary except if digit follows */
362 		REQUIRE(!MORE() || !isdigit(PEEK()), REG_BADRPT);
363 		/* FALLTHROUGH */
364 	default:
365 		ordinary(p, c);
366 		break;
367 	}
368 
369 	if (!MORE())
370 		return;
371 	c = PEEK();
372 	/* we call { a repetition if followed by a digit */
373 	if (!( c == '*' || c == '+' || c == '?' ||
374 				(c == '{' && MORE2() && isdigit(PEEK2())) ))
375 		return;		/* no repetition, we're done */
376 	NEXT();
377 
378 	REQUIRE(!wascaret, REG_BADRPT);
379 	switch (c) {
380 	case '*':	/* implemented as +? */
381 		/* this case does not require the (y|) trick, noKLUDGE */
382 		INSERT(OPLUS_, pos);
383 		ASTERN(O_PLUS, pos);
384 		INSERT(OQUEST_, pos);
385 		ASTERN(O_QUEST, pos);
386 		break;
387 	case '+':
388 		INSERT(OPLUS_, pos);
389 		ASTERN(O_PLUS, pos);
390 		break;
391 	case '?':
392 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
393 		INSERT(OCH_, pos);		/* offset slightly wrong */
394 		ASTERN(OOR1, pos);		/* this one's right */
395 		AHEAD(pos);			/* fix the OCH_ */
396 		EMIT(OOR2, 0);			/* offset very wrong... */
397 		AHEAD(THERE());			/* ...so fix it */
398 		ASTERN(O_CH, THERETHERE());
399 		break;
400 	case '{':
401 		count = p_count(p);
402 		if (EAT(',')) {
403 			if (isdigit(PEEK())) {
404 				count2 = p_count(p);
405 				REQUIRE(count <= count2, REG_BADBR);
406 			} else		/* single number with comma */
407 				count2 = INFINITY;
408 		} else		/* just a single number */
409 			count2 = count;
410 		repeat(p, pos, count, count2);
411 		if (!EAT('}')) {	/* error heuristics */
412 			while (MORE() && PEEK() != '}')
413 				NEXT();
414 			REQUIRE(MORE(), REG_EBRACE);
415 			SETERROR(REG_BADBR);
416 		}
417 		break;
418 	}
419 
420 	if (!MORE())
421 		return;
422 	c = PEEK();
423 	if (!( c == '*' || c == '+' || c == '?' ||
424 				(c == '{' && MORE2() && isdigit(PEEK2())) ) )
425 		return;
426 	SETERROR(REG_BADRPT);
427 }
428 
429 /*
430  - p_str - string (no metacharacters) "parser"
431  == static void p_str(register struct parse *p);
432  */
433 static void
p_str(p)434 p_str(p)
435 register struct parse *p;
436 {
437 	REQUIRE(MORE(), REG_EMPTY);
438 	while (MORE())
439 		ordinary(p, GETNEXT());
440 }
441 
442 /*
443  - p_bre - BRE parser top level, anchoring and concatenation
444  == static void p_bre(register struct parse *p, register int end1, \
445  ==	register int end2);
446  * Giving end1 as OUT essentially eliminates the end1/end2 check.
447  *
448  * This implementation is a bit of a kludge, in that a trailing $ is first
449  * taken as an ordinary character and then revised to be an anchor.  The
450  * only undesirable side effect is that '$' gets included as a character
451  * category in such cases.  This is fairly harmless; not worth fixing.
452  * The amount of lookahead needed to avoid this kludge is excessive.
453  */
454 static void
p_bre(p,end1,end2)455 p_bre(p, end1, end2)
456 register struct parse *p;
457 register int end1;		/* first terminating character */
458 register int end2;		/* second terminating character */
459 {
460 	register sopno start = HERE();
461 	register int first = 1;			/* first subexpression? */
462 	register int wasdollar = 0;
463 
464 	if (EAT('^')) {
465 		EMIT(OBOL, 0);
466 		p->g->iflags |= USEBOL;
467 		p->g->nbol++;
468 	}
469 	while (MORE() && !SEETWO(end1, end2)) {
470 		wasdollar = p_simp_re(p, first);
471 		first = 0;
472 	}
473 	if (wasdollar) {	/* oops, that was a trailing anchor */
474 		DROP(1);
475 		EMIT(OEOL, 0);
476 		p->g->iflags |= USEEOL;
477 		p->g->neol++;
478 	}
479 
480 	REQUIRE(HERE() != start, REG_EMPTY);	/* require nonempty */
481 }
482 
483 /*
484  - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
485  == static int p_simp_re(register struct parse *p, int starordinary);
486  */
487 static int			/* was the simple RE an unbackslashed $? */
p_simp_re(p,starordinary)488 p_simp_re(p, starordinary)
489 register struct parse *p;
490 int starordinary;		/* is a leading * an ordinary character? */
491 {
492 	register int c;
493 	register int count;
494 	register int count2;
495 	register sopno pos;
496 	register int i;
497 	register sopno subno;
498 #	define	BACKSL	(1<<CHAR_BIT)
499 
500 	pos = HERE();		/* repetion op, if any, covers from here */
501 
502 	assert(MORE());		/* caller should have ensured this */
503 	c = GETNEXT();
504 	if (c == '\\') {
505 		REQUIRE(MORE(), REG_EESCAPE);
506 		c = BACKSL | (unsigned char)GETNEXT();
507 	}
508 	switch (c) {
509 	case '.':
510 		if (p->g->cflags&REG_NEWLINE)
511 			nonnewline(p);
512 		else
513 			EMIT(OANY, 0);
514 		break;
515 	case '[':
516 		p_bracket(p);
517 		break;
518 	case BACKSL|'{':
519 		SETERROR(REG_BADRPT);
520 		break;
521 	case BACKSL|'(':
522 		p->g->nsub++;
523 		subno = p->g->nsub;
524 		if (subno < NPAREN)
525 			p->pbegin[subno] = HERE();
526 		EMIT(OLPAREN, subno);
527 		/* the MORE here is an error heuristic */
528 		if (MORE() && !SEETWO('\\', ')'))
529 			p_bre(p, '\\', ')');
530 		if (subno < NPAREN) {
531 			p->pend[subno] = HERE();
532 			assert(p->pend[subno] != 0);
533 		}
534 		EMIT(ORPAREN, subno);
535 		REQUIRE(EATTWO('\\', ')'), REG_EPAREN);
536 		break;
537 	case BACKSL|')':	/* should not get here -- must be user */
538 	case BACKSL|'}':
539 		SETERROR(REG_EPAREN);
540 		break;
541 	case BACKSL|'1':
542 	case BACKSL|'2':
543 	case BACKSL|'3':
544 	case BACKSL|'4':
545 	case BACKSL|'5':
546 	case BACKSL|'6':
547 	case BACKSL|'7':
548 	case BACKSL|'8':
549 	case BACKSL|'9':
550 		i = (c&~BACKSL) - '0';
551 		assert(i < NPAREN);
552 		if (p->pend[i] != 0) {
553 			assert(i <= p->g->nsub);
554 			EMIT(OBACK_, i);
555 			assert(p->pbegin[i] != 0);
556 			assert(OP(p->strip[p->pbegin[i]]) == OLPAREN);
557 			assert(OP(p->strip[p->pend[i]]) == ORPAREN);
558 			(void) dupl(p, p->pbegin[i]+1, p->pend[i]);
559 			EMIT(O_BACK, i);
560 		} else
561 			SETERROR(REG_ESUBREG);
562 		p->g->backrefs = 1;
563 		break;
564 	case '*':
565 		REQUIRE(starordinary, REG_BADRPT);
566 		/* FALLTHROUGH */
567 	default:
568 		ordinary(p, (char)c);	/* takes off BACKSL, if any */
569 		break;
570 	}
571 
572 	if (EAT('*')) {		/* implemented as +? */
573 		/* this case does not require the (y|) trick, noKLUDGE */
574 		INSERT(OPLUS_, pos);
575 		ASTERN(O_PLUS, pos);
576 		INSERT(OQUEST_, pos);
577 		ASTERN(O_QUEST, pos);
578 	} else if (EATTWO('\\', '{')) {
579 		count = p_count(p);
580 		if (EAT(',')) {
581 			if (MORE() && isdigit(PEEK())) {
582 				count2 = p_count(p);
583 				REQUIRE(count <= count2, REG_BADBR);
584 			} else		/* single number with comma */
585 				count2 = INFINITY;
586 		} else		/* just a single number */
587 			count2 = count;
588 		repeat(p, pos, count, count2);
589 		if (!EATTWO('\\', '}')) {	/* error heuristics */
590 			while (MORE() && !SEETWO('\\', '}'))
591 				NEXT();
592 			REQUIRE(MORE(), REG_EBRACE);
593 			SETERROR(REG_BADBR);
594 		}
595 	} else if (c == (unsigned char)'$')	/* $ (but not \$) ends it */
596 		return(1);
597 
598 	return(0);
599 }
600 
601 /*
602  - p_count - parse a repetition count
603  == static int p_count(register struct parse *p);
604  */
605 static int			/* the value */
p_count(p)606 p_count(p)
607 register struct parse *p;
608 {
609 	register int count = 0;
610 	register int ndigits = 0;
611 
612 	while (MORE() && isdigit(PEEK()) && count <= DUPMAX) {
613 		count = count*10 + (GETNEXT() - '0');
614 		ndigits++;
615 	}
616 
617 	REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
618 	return(count);
619 }
620 
621 /*
622  - p_bracket - parse a bracketed character list
623  == static void p_bracket(register struct parse *p);
624  *
625  * Note a significant property of this code:  if the allocset() did SETERROR,
626  * no set operations are done.
627  */
628 static void
p_bracket(p)629 p_bracket(p)
630 register struct parse *p;
631 {
632 	register cset *cs = allocset(p);
633 	register int invert = 0;
634 
635 	/* Dept of Truly Sickening Special-Case Kludges */
636 	if (p->next + 5 < p->end && strncmp(p->next, "[:<:]]", 6) == 0) {
637 		EMIT(OBOW, 0);
638 		NEXTn(6);
639 		return;
640 	}
641 	if (p->next + 5 < p->end && strncmp(p->next, "[:>:]]", 6) == 0) {
642 		EMIT(OEOW, 0);
643 		NEXTn(6);
644 		return;
645 	}
646 
647 	if (EAT('^'))
648 		invert++;	/* make note to invert set at end */
649 	if (EAT(']'))
650 		CHadd(cs, ']');
651 	else if (EAT('-'))
652 		CHadd(cs, '-');
653 	while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
654 		p_b_term(p, cs);
655 	if (EAT('-'))
656 		CHadd(cs, '-');
657 	MUSTEAT(']', REG_EBRACK);
658 
659 	if (p->error != 0)	/* don't mess things up further */
660 		return;
661 
662 	if (p->g->cflags&REG_ICASE) {
663 		register int i;
664 		register int ci;
665 
666 		for (i = p->g->csetsize - 1; i >= 0; i--)
667 			if (CHIN(cs, i) && isalpha(i)) {
668 				ci = othercase(i);
669 				if (ci != i)
670 					CHadd(cs, ci);
671 			}
672 		if (cs->multis != NULL)
673 			mccase(p, cs);
674 	}
675 	if (invert) {
676 		register int i;
677 
678 		for (i = p->g->csetsize - 1; i >= 0; i--)
679 			if (CHIN(cs, i))
680 				CHsub(cs, i);
681 			else
682 				CHadd(cs, i);
683 		if (p->g->cflags&REG_NEWLINE)
684 			CHsub(cs, '\n');
685 		if (cs->multis != NULL)
686 			mcinvert(p, cs);
687 	}
688 
689 	assert(cs->multis == NULL);		/* xxx */
690 
691 	if (nch(p, cs) == 1) {		/* optimize singleton sets */
692 		ordinary(p, firstch(p, cs));
693 		freeset(p, cs);
694 	} else
695 		EMIT(OANYOF, freezeset(p, cs));
696 }
697 
698 /*
699  - p_b_term - parse one term of a bracketed character list
700  == static void p_b_term(register struct parse *p, register cset *cs);
701  */
702 static void
p_b_term(p,cs)703 p_b_term(p, cs)
704 register struct parse *p;
705 register cset *cs;
706 {
707 	register char c;
708 	register char start, finish;
709 	register int i;
710 
711 	/* classify what we've got */
712 	switch ((MORE()) ? PEEK() : '\0') {
713 	case '[':
714 		c = (MORE2()) ? PEEK2() : '\0';
715 		break;
716 	case '-':
717 		SETERROR(REG_ERANGE);
718 		return;			/* NOTE RETURN */
719 		break;
720 	default:
721 		c = '\0';
722 		break;
723 	}
724 
725 	switch (c) {
726 	case ':':		/* character class */
727 		NEXT2();
728 		REQUIRE(MORE(), REG_EBRACK);
729 		c = PEEK();
730 		REQUIRE(c != '-' && c != ']', REG_ECTYPE);
731 		p_b_cclass(p, cs);
732 		REQUIRE(MORE(), REG_EBRACK);
733 		REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
734 		break;
735 	case '=':		/* equivalence class */
736 		NEXT2();
737 		REQUIRE(MORE(), REG_EBRACK);
738 		c = PEEK();
739 		REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
740 		p_b_eclass(p, cs);
741 		REQUIRE(MORE(), REG_EBRACK);
742 		REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
743 		break;
744 	default:		/* symbol, ordinary character, or range */
745 /* xxx revision needed for multichar stuff */
746 		start = p_b_symbol(p);
747 		if (SEE('-') && MORE2() && PEEK2() != ']') {
748 			/* range */
749 			NEXT();
750 			if (EAT('-'))
751 				finish = '-';
752 			else
753 				finish = p_b_symbol(p);
754 		} else
755 			finish = start;
756 /* xxx what about signed chars here... */
757 		REQUIRE(start <= finish, REG_ERANGE);
758 		for (i = start; i <= finish; i++)
759 			CHadd(cs, i);
760 		break;
761 	}
762 }
763 
764 /*
765  - p_b_cclass - parse a character-class name and deal with it
766  == static void p_b_cclass(register struct parse *p, register cset *cs);
767  */
768 static void
p_b_cclass(p,cs)769 p_b_cclass(p, cs)
770 register struct parse *p;
771 register cset *cs;
772 {
773 	register char *sp = p->next;
774 	register struct cclass *cp;
775 	register size_t len;
776 	register char *u;
777 	register char c;
778 
779 	while (MORE() && isalpha(PEEK()))
780 		NEXT();
781 	len = p->next - sp;
782 	for (cp = cclasses; cp->name != NULL; cp++)
783 		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
784 			break;
785 	if (cp->name == NULL) {
786 		/* oops, didn't find it */
787 		SETERROR(REG_ECTYPE);
788 		return;
789 	}
790 
791 	u = cp->chars;
792 	while ((c = *u++) != '\0')
793 		CHadd(cs, c);
794 	for (u = cp->multis; *u != '\0'; u += strlen(u) + 1)
795 		MCadd(p, cs, u);
796 }
797 
798 /*
799  - p_b_eclass - parse an equivalence-class name and deal with it
800  == static void p_b_eclass(register struct parse *p, register cset *cs);
801  *
802  * This implementation is incomplete. xxx
803  */
804 static void
p_b_eclass(p,cs)805 p_b_eclass(p, cs)
806 register struct parse *p;
807 register cset *cs;
808 {
809 	register char c;
810 
811 	c = p_b_coll_elem(p, '=');
812 	CHadd(cs, c);
813 }
814 
815 /*
816  - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
817  == static char p_b_symbol(register struct parse *p);
818  */
819 static char			/* value of symbol */
p_b_symbol(p)820 p_b_symbol(p)
821 register struct parse *p;
822 {
823 	register char value;
824 
825 	REQUIRE(MORE(), REG_EBRACK);
826 	if (!EATTWO('[', '.'))
827 		return(GETNEXT());
828 
829 	/* collating symbol */
830 	value = p_b_coll_elem(p, '.');
831 	REQUIRE(EATTWO('.', ']'), REG_ECOLLATE);
832 	return(value);
833 }
834 
835 /*
836  - p_b_coll_elem - parse a collating-element name and look it up
837  == static char p_b_coll_elem(register struct parse *p, int endc);
838  */
839 static char			/* value of collating element */
p_b_coll_elem(p,endc)840 p_b_coll_elem(p, endc)
841 register struct parse *p;
842 int endc;			/* name ended by endc,']' */
843 {
844 	register char *sp = p->next;
845 	register struct cname *cp;
846 	register int len;
847 
848 	while (MORE() && !SEETWO(endc, ']'))
849 		NEXT();
850 	if (!MORE()) {
851 		SETERROR(REG_EBRACK);
852 		return(0);
853 	}
854 	len = p->next - sp;
855 	for (cp = cnames; cp->name != NULL; cp++)
856 		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
857 			return(cp->code);	/* known name */
858 	if (len == 1)
859 		return(*sp);	/* single character */
860 	SETERROR(REG_ECOLLATE);			/* neither */
861 	return(0);
862 }
863 
864 /*
865  - othercase - return the case counterpart of an alphabetic
866  == static char othercase(int ch);
867  */
868 static char			/* if no counterpart, return ch */
othercase(ch)869 othercase(ch)
870 int ch;
871 {
872 	assert(isalpha(ch));
873 	if (isupper(ch))
874 		return(tolower(ch));
875 	else if (islower(ch))
876 		return(toupper(ch));
877 	else			/* peculiar, but could happen */
878 		return(ch);
879 }
880 
881 /*
882  - bothcases - emit a dualcase version of a two-case character
883  == static void bothcases(register struct parse *p, int ch);
884  *
885  * Boy, is this implementation ever a kludge...
886  */
887 static void
bothcases(p,ch)888 bothcases(p, ch)
889 register struct parse *p;
890 int ch;
891 {
892 	register char *oldnext = p->next;
893 	register char *oldend = p->end;
894 	char bracket[3];
895 
896 	assert(othercase(ch) != ch);	/* p_bracket() would recurse */
897 	p->next = bracket;
898 	p->end = bracket+2;
899 	bracket[0] = ch;
900 	bracket[1] = ']';
901 	bracket[2] = '\0';
902 	p_bracket(p);
903 	assert(p->next == bracket+2);
904 	p->next = oldnext;
905 	p->end = oldend;
906 }
907 
908 /*
909  - ordinary - emit an ordinary character
910  == static void ordinary(register struct parse *p, register int ch);
911  */
912 static void
ordinary(p,ch)913 ordinary(p, ch)
914 register struct parse *p;
915 register int ch;
916 {
917 	register cat_t *cap = p->g->categories;
918 
919 	if ((p->g->cflags&REG_ICASE) && isalpha(ch) && othercase(ch) != ch)
920 		bothcases(p, ch);
921 	else {
922 		EMIT(OCHAR, (unsigned char)ch);
923 		if (cap[ch] == 0)
924 			cap[ch] = p->g->ncategories++;
925 	}
926 }
927 
928 /*
929  - nonnewline - emit REG_NEWLINE version of OANY
930  == static void nonnewline(register struct parse *p);
931  *
932  * Boy, is this implementation ever a kludge...
933  */
934 static void
nonnewline(p)935 nonnewline(p)
936 register struct parse *p;
937 {
938 	register char *oldnext = p->next;
939 	register char *oldend = p->end;
940 	char bracket[4];
941 
942 	p->next = bracket;
943 	p->end = bracket+3;
944 	bracket[0] = '^';
945 	bracket[1] = '\n';
946 	bracket[2] = ']';
947 	bracket[3] = '\0';
948 	p_bracket(p);
949 	assert(p->next == bracket+3);
950 	p->next = oldnext;
951 	p->end = oldend;
952 }
953 
954 /*
955  - repeat - generate code for a bounded repetition, recursively if needed
956  == static void repeat(register struct parse *p, sopno start, int from, int to);
957  */
958 static void
repeat(p,start,from,to)959 repeat(p, start, from, to)
960 register struct parse *p;
961 sopno start;			/* operand from here to end of strip */
962 int from;			/* repeated from this number */
963 int to;				/* to this number of times (maybe INFINITY) */
964 {
965 	register sopno finish = HERE();
966 #	define	N	2
967 #	define	INF	3
968 #	define	REP(f, t)	((f)*8 + (t))
969 #	define	MAP(n)	(((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N)
970 	register sopno copy;
971 
972 	if (p->error != 0)	/* head off possible runaway recursion */
973 		return;
974 
975 	assert(from <= to);
976 
977 	switch (REP(MAP(from), MAP(to))) {
978 	case REP(0, 0):			/* must be user doing this */
979 		DROP(finish-start);	/* drop the operand */
980 		break;
981 	case REP(0, 1):			/* as x{1,1}? */
982 	case REP(0, N):			/* as x{1,n}? */
983 	case REP(0, INF):		/* as x{1,}? */
984 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
985 		INSERT(OCH_, start);		/* offset is wrong... */
986 		repeat(p, start+1, 1, to);
987 		ASTERN(OOR1, start);
988 		AHEAD(start);			/* ... fix it */
989 		EMIT(OOR2, 0);
990 		AHEAD(THERE());
991 		ASTERN(O_CH, THERETHERE());
992 		break;
993 	case REP(1, 1):			/* trivial case */
994 		/* done */
995 		break;
996 	case REP(1, N):			/* as x?x{1,n-1} */
997 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
998 		INSERT(OCH_, start);
999 		ASTERN(OOR1, start);
1000 		AHEAD(start);
1001 		EMIT(OOR2, 0);			/* offset very wrong... */
1002 		AHEAD(THERE());			/* ...so fix it */
1003 		ASTERN(O_CH, THERETHERE());
1004 		copy = dupl(p, start+1, finish+1);
1005 		assert(copy == finish+4);
1006 		repeat(p, copy, 1, to-1);
1007 		break;
1008 	case REP(1, INF):		/* as x+ */
1009 		INSERT(OPLUS_, start);
1010 		ASTERN(O_PLUS, start);
1011 		break;
1012 	case REP(N, N):			/* as xx{m-1,n-1} */
1013 		copy = dupl(p, start, finish);
1014 		repeat(p, copy, from-1, to-1);
1015 		break;
1016 	case REP(N, INF):		/* as xx{n-1,INF} */
1017 		copy = dupl(p, start, finish);
1018 		repeat(p, copy, from-1, to);
1019 		break;
1020 	default:			/* "can't happen" */
1021 		SETERROR(REG_ASSERT);	/* just in case */
1022 		break;
1023 	}
1024 }
1025 
1026 /*
1027  - seterr - set an error condition
1028  == static int seterr(register struct parse *p, int e);
1029  */
1030 static int			/* useless but makes type checking happy */
seterr(p,e)1031 seterr(p, e)
1032 register struct parse *p;
1033 int e;
1034 {
1035 	if (p->error == 0)	/* keep earliest error condition */
1036 		p->error = e;
1037 	p->next = nuls;		/* try to bring things to a halt */
1038 	p->end = nuls;
1039 	return(0);		/* make the return value well-defined */
1040 }
1041 
1042 /*
1043  - allocset - allocate a set of characters for []
1044  == static cset *allocset(register struct parse *p);
1045  */
1046 static cset *
allocset(p)1047 allocset(p)
1048 register struct parse *p;
1049 {
1050 	register int no = p->g->ncsets++;
1051 	register size_t nc;
1052 	register size_t nbytes;
1053 	register cset *cs;
1054 	register size_t css = (size_t)p->g->csetsize;
1055 	register int i;
1056 
1057 	if (no >= p->ncsalloc) {	/* need another column of space */
1058 		p->ncsalloc += CHAR_BIT;
1059 		nc = p->ncsalloc;
1060 		assert(nc % CHAR_BIT == 0);
1061 		nbytes = nc / CHAR_BIT * css;
1062 		if (p->g->sets == NULL)
1063 			p->g->sets = (cset *)malloc(nc * sizeof(cset));
1064 		else
1065 			p->g->sets = (cset *)realloc((char *)p->g->sets,
1066 							nc * sizeof(cset));
1067 		if (p->g->setbits == NULL)
1068 			p->g->setbits = (uch *)malloc(nbytes);
1069 		else {
1070 			p->g->setbits = (uch *)realloc((char *)p->g->setbits,
1071 								nbytes);
1072 			/* xxx this isn't right if setbits is now NULL */
1073 			for (i = 0; i < no; i++)
1074 				p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT);
1075 		}
1076 		if (p->g->sets != NULL && p->g->setbits != NULL)
1077 			(void) memset((char *)p->g->setbits + (nbytes - css),
1078 								0, css);
1079 		else {
1080 			no = 0;
1081 			SETERROR(REG_ESPACE);
1082 			/* caller's responsibility not to do set ops */
1083 		}
1084 	}
1085 
1086 	assert(p->g->sets != NULL);	/* xxx */
1087 	cs = &p->g->sets[no];
1088 	cs->ptr = p->g->setbits + css*((no)/CHAR_BIT);
1089 	cs->mask = 1 << ((no) % CHAR_BIT);
1090 	cs->hash = 0;
1091 	cs->smultis = 0;
1092 	cs->multis = NULL;
1093 
1094 	return(cs);
1095 }
1096 
1097 /*
1098  - freeset - free a now-unused set
1099  == static void freeset(register struct parse *p, register cset *cs);
1100  */
1101 static void
freeset(p,cs)1102 freeset(p, cs)
1103 register struct parse *p;
1104 register cset *cs;
1105 {
1106 	register int i;
1107 	register cset *top = &p->g->sets[p->g->ncsets];
1108 	register size_t css = (size_t)p->g->csetsize;
1109 
1110 	for (i = 0; (size_t)i < css; i++)
1111 		CHsub(cs, i);
1112 	if (cs == top-1)	/* recover only the easy case */
1113 		p->g->ncsets--;
1114 }
1115 
1116 /*
1117  - freezeset - final processing on a set of characters
1118  == static int freezeset(register struct parse *p, register cset *cs);
1119  *
1120  * The main task here is merging identical sets.  This is usually a waste
1121  * of time (although the hash code minimizes the overhead), but can win
1122  * big if REG_ICASE is being used.  REG_ICASE, by the way, is why the hash
1123  * is done using addition rather than xor -- all ASCII [aA] sets xor to
1124  * the same value!
1125  */
1126 static int			/* set number */
freezeset(p,cs)1127 freezeset(p, cs)
1128 register struct parse *p;
1129 register cset *cs;
1130 {
1131 	register uch h = cs->hash;
1132 	register int i;
1133 	register cset *top = &p->g->sets[p->g->ncsets];
1134 	register cset *cs2;
1135 	register size_t css = (size_t)p->g->csetsize;
1136 
1137 	/* look for an earlier one which is the same */
1138 	for (cs2 = &p->g->sets[0]; cs2 < top; cs2++)
1139 		if (cs2->hash == h && cs2 != cs) {
1140 			/* maybe */
1141 			for (i = 0; (size_t)i < css; i++)
1142 				if (!!CHIN(cs2, i) != !!CHIN(cs, i))
1143 					break;		/* no */
1144 			if (i == css)
1145 				break;			/* yes */
1146 		}
1147 
1148 	if (cs2 < top) {	/* found one */
1149 		freeset(p, cs);
1150 		cs = cs2;
1151 	}
1152 
1153 	return((int)(cs - p->g->sets));
1154 }
1155 
1156 /*
1157  - firstch - return first character in a set (which must have at least one)
1158  == static int firstch(register struct parse *p, register cset *cs);
1159  */
1160 static int			/* character; there is no "none" value */
firstch(p,cs)1161 firstch(p, cs)
1162 register struct parse *p;
1163 register cset *cs;
1164 {
1165 	register int i;
1166 	register size_t css = (size_t)p->g->csetsize;
1167 
1168 	for (i = 0; (size_t)i < css; i++)
1169 		if (CHIN(cs, i))
1170 			return((char)i);
1171 	assert(never);
1172 	return(0);		/* arbitrary */
1173 }
1174 
1175 /*
1176  - nch - number of characters in a set
1177  == static int nch(register struct parse *p, register cset *cs);
1178  */
1179 static int
nch(p,cs)1180 nch(p, cs)
1181 register struct parse *p;
1182 register cset *cs;
1183 {
1184 	register int i;
1185 	register size_t css = (size_t)p->g->csetsize;
1186 	register int n = 0;
1187 
1188 	for (i = 0; (size_t)i < css; i++)
1189 		if (CHIN(cs, i))
1190 			n++;
1191 	return(n);
1192 }
1193 
1194 /*
1195  - mcadd - add a collating element to a cset
1196  == static void mcadd(register struct parse *p, register cset *cs, \
1197  ==	register char *cp);
1198  */
1199 static void
mcadd(p,cs,cp)1200 mcadd(p, cs, cp)
1201 register struct parse *p;
1202 register cset *cs;
1203 register char *cp;
1204 {
1205 	register size_t oldend = cs->smultis;
1206 
1207 	cs->smultis += strlen(cp) + 1;
1208 	if (cs->multis == NULL)
1209 		cs->multis = malloc(cs->smultis);
1210 	else
1211 		cs->multis = realloc(cs->multis, cs->smultis);
1212 	if (cs->multis == NULL) {
1213 		SETERROR(REG_ESPACE);
1214 		return;
1215 	}
1216 
1217 	(void) strcpy(cs->multis + oldend - 1, cp);
1218 	cs->multis[cs->smultis - 1] = '\0';
1219 }
1220 
1221 /*
1222  - mcsub - subtract a collating element from a cset
1223  == static void mcsub(register cset *cs, register char *cp);
1224  */
1225 static void
mcsub(cs,cp)1226 mcsub(cs, cp)
1227 register cset *cs;
1228 register char *cp;
1229 {
1230 	register char *fp = mcfind(cs, cp);
1231 	register size_t len = strlen(fp);
1232 
1233 	assert(fp != NULL);
1234 	(void) memmove(fp, fp + len + 1,
1235 				cs->smultis - (fp + len + 1 - cs->multis));
1236 	cs->smultis -= len;
1237 
1238 	if (cs->smultis == 0) {
1239 		free(cs->multis);
1240 		cs->multis = NULL;
1241 		return;
1242 	}
1243 
1244 	cs->multis = realloc(cs->multis, cs->smultis);
1245 	assert(cs->multis != NULL);
1246 }
1247 
1248 /*
1249  - mcin - is a collating element in a cset?
1250  == static int mcin(register cset *cs, register char *cp);
1251  */
1252 static int
mcin(cs,cp)1253 mcin(cs, cp)
1254 register cset *cs;
1255 register char *cp;
1256 {
1257 	return(mcfind(cs, cp) != NULL);
1258 }
1259 
1260 /*
1261  - mcfind - find a collating element in a cset
1262  == static char *mcfind(register cset *cs, register char *cp);
1263  */
1264 static char *
mcfind(cs,cp)1265 mcfind(cs, cp)
1266 register cset *cs;
1267 register char *cp;
1268 {
1269 	register char *p;
1270 
1271 	if (cs->multis == NULL)
1272 		return(NULL);
1273 	for (p = cs->multis; *p != '\0'; p += strlen(p) + 1)
1274 		if (strcmp(cp, p) == 0)
1275 			return(p);
1276 	return(NULL);
1277 }
1278 
1279 /*
1280  - mcinvert - invert the list of collating elements in a cset
1281  == static void mcinvert(register struct parse *p, register cset *cs);
1282  *
1283  * This would have to know the set of possibilities.  Implementation
1284  * is deferred.
1285  */
1286 static void
mcinvert(p,cs)1287 mcinvert(p, cs)
1288 register struct parse *p;
1289 register cset *cs;
1290 {
1291 	assert(cs->multis == NULL);	/* xxx */
1292 }
1293 
1294 /*
1295  - mccase - add case counterparts of the list of collating elements in a cset
1296  == static void mccase(register struct parse *p, register cset *cs);
1297  *
1298  * This would have to know the set of possibilities.  Implementation
1299  * is deferred.
1300  */
1301 static void
mccase(p,cs)1302 mccase(p, cs)
1303 register struct parse *p;
1304 register cset *cs;
1305 {
1306 	assert(cs->multis == NULL);	/* xxx */
1307 }
1308 
1309 /*
1310  - isinsets - is this character in any sets?
1311  == static int isinsets(register struct re_guts *g, int c);
1312  */
1313 static int			/* predicate */
isinsets(g,c)1314 isinsets(g, c)
1315 register struct re_guts *g;
1316 int c;
1317 {
1318 	register uch *col;
1319 	register int i;
1320 	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
1321 	register unsigned uc = (unsigned char)c;
1322 
1323 	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1324 		if (col[uc] != 0)
1325 			return(1);
1326 	return(0);
1327 }
1328 
1329 /*
1330  - samesets - are these two characters in exactly the same sets?
1331  == static int samesets(register struct re_guts *g, int c1, int c2);
1332  */
1333 static int			/* predicate */
samesets(g,c1,c2)1334 samesets(g, c1, c2)
1335 register struct re_guts *g;
1336 int c1;
1337 int c2;
1338 {
1339 	register uch *col;
1340 	register int i;
1341 	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
1342 	register unsigned uc1 = (unsigned char)c1;
1343 	register unsigned uc2 = (unsigned char)c2;
1344 
1345 	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1346 		if (col[uc1] != col[uc2])
1347 			return(0);
1348 	return(1);
1349 }
1350 
1351 /*
1352  - categorize - sort out character categories
1353  == static void categorize(struct parse *p, register struct re_guts *g);
1354  */
1355 static void
categorize(p,g)1356 categorize(p, g)
1357 struct parse *p;
1358 register struct re_guts *g;
1359 {
1360 	register cat_t *cats = g->categories;
1361 	register int c;
1362 	register int c2;
1363 	register cat_t cat;
1364 
1365 	/* avoid making error situations worse */
1366 	if (p->error != 0)
1367 		return;
1368 
1369 	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
1370 		if (cats[c] == 0 && isinsets(g, c)) {
1371 			cat = g->ncategories++;
1372 			cats[c] = cat;
1373 			for (c2 = c+1; c2 <= CHAR_MAX; c2++)
1374 				if (cats[c2] == 0 && samesets(g, c, c2))
1375 					cats[c2] = cat;
1376 		}
1377 }
1378 
1379 /*
1380  - dupl - emit a duplicate of a bunch of sops
1381  == static sopno dupl(register struct parse *p, sopno start, sopno finish);
1382  */
1383 static sopno			/* start of duplicate */
dupl(p,start,finish)1384 dupl(p, start, finish)
1385 register struct parse *p;
1386 sopno start;			/* from here */
1387 sopno finish;			/* to this less one */
1388 {
1389 	register sopno ret = HERE();
1390 	register sopno len = finish - start;
1391 
1392 	assert(finish >= start);
1393 	if (len == 0)
1394 		return(ret);
1395 	enlarge(p, p->ssize + len);	/* this many unexpected additions */
1396 	assert(p->ssize >= p->slen + len);
1397 	(void) memcpy((char *)(p->strip + p->slen),
1398 		(char *)(p->strip + start), (size_t)len*sizeof(sop));
1399 	p->slen += len;
1400 	return(ret);
1401 }
1402 
1403 /*
1404  - doemit - emit a strip operator
1405  == static void doemit(register struct parse *p, sop op, size_t opnd);
1406  *
1407  * It might seem better to implement this as a macro with a function as
1408  * hard-case backup, but it's just too big and messy unless there are
1409  * some changes to the data structures.  Maybe later.
1410  */
1411 static void
doemit(p,op,opnd)1412 doemit(p, op, opnd)
1413 register struct parse *p;
1414 sop op;
1415 size_t opnd;
1416 {
1417 	/* avoid making error situations worse */
1418 	if (p->error != 0)
1419 		return;
1420 
1421 	/* deal with oversize operands ("can't happen", more or less) */
1422 	assert(opnd < 1<<OPSHIFT);
1423 
1424 	/* deal with undersized strip */
1425 	if (p->slen >= p->ssize)
1426 		enlarge(p, (p->ssize+1) / 2 * 3);	/* +50% */
1427 	assert(p->slen < p->ssize);
1428 
1429 	/* finally, it's all reduced to the easy case */
1430 	p->strip[p->slen++] = SOP(op, opnd);
1431 }
1432 
1433 /*
1434  - doinsert - insert a sop into the strip
1435  == static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
1436  */
1437 static void
doinsert(p,op,opnd,pos)1438 doinsert(p, op, opnd, pos)
1439 register struct parse *p;
1440 sop op;
1441 size_t opnd;
1442 sopno pos;
1443 {
1444 	register sopno sn;
1445 	register sop s;
1446 	register int i;
1447 
1448 	/* avoid making error situations worse */
1449 	if (p->error != 0)
1450 		return;
1451 
1452 	sn = HERE();
1453 	EMIT(op, opnd);		/* do checks, ensure space */
1454 	assert(HERE() == sn+1);
1455 	s = p->strip[sn];
1456 
1457 	/* adjust paren pointers */
1458 	assert(pos > 0);
1459 	for (i = 1; i < NPAREN; i++) {
1460 		if (p->pbegin[i] >= pos) {
1461 			p->pbegin[i]++;
1462 		}
1463 		if (p->pend[i] >= pos) {
1464 			p->pend[i]++;
1465 		}
1466 	}
1467 
1468 	memmove((char *)&p->strip[pos+1], (char *)&p->strip[pos],
1469 						(HERE()-pos-1)*sizeof(sop));
1470 	p->strip[pos] = s;
1471 }
1472 
1473 /*
1474  - dofwd - complete a forward reference
1475  == static void dofwd(register struct parse *p, sopno pos, sop value);
1476  */
1477 static void
dofwd(p,pos,value)1478 dofwd(p, pos, value)
1479 register struct parse *p;
1480 register sopno pos;
1481 sop value;
1482 {
1483 	/* avoid making error situations worse */
1484 	if (p->error != 0)
1485 		return;
1486 
1487 	assert(value < 1<<OPSHIFT);
1488 	p->strip[pos] = OP(p->strip[pos]) | value;
1489 }
1490 
1491 /*
1492  - enlarge - enlarge the strip
1493  == static void enlarge(register struct parse *p, sopno size);
1494  */
1495 static void
enlarge(p,size)1496 enlarge(p, size)
1497 register struct parse *p;
1498 register sopno size;
1499 {
1500 	register sop *sp;
1501 
1502 	if (p->ssize >= size)
1503 		return;
1504 
1505 	sp = (sop *)realloc(p->strip, size*sizeof(sop));
1506 	if (sp == NULL) {
1507 		SETERROR(REG_ESPACE);
1508 		return;
1509 	}
1510 	p->strip = sp;
1511 	p->ssize = size;
1512 }
1513 
1514 /*
1515  - stripsnug - compact the strip
1516  == static void stripsnug(register struct parse *p, register struct re_guts *g);
1517  */
1518 static void
stripsnug(p,g)1519 stripsnug(p, g)
1520 register struct parse *p;
1521 register struct re_guts *g;
1522 {
1523 	g->nstates = p->slen;
1524 	g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
1525 	if (g->strip == NULL) {
1526 		SETERROR(REG_ESPACE);
1527 		g->strip = p->strip;
1528 	}
1529 }
1530 
1531 /*
1532  - findmust - fill in must and mlen with longest mandatory literal string
1533  == static void findmust(register struct parse *p, register struct re_guts *g);
1534  *
1535  * This algorithm could do fancy things like analyzing the operands of |
1536  * for common subsequences.  Someday.  This code is simple and finds most
1537  * of the interesting cases.
1538  *
1539  * Note that must and mlen got initialized during setup.
1540  */
1541 static void
findmust(p,g)1542 findmust(p, g)
1543 struct parse *p;
1544 register struct re_guts *g;
1545 {
1546 	register sop *scan;
1547 	sop *start = NULL;
1548 	register sop *newstart = NULL;
1549 	register sopno newlen;
1550 	register sop s;
1551 	register char *cp;
1552 	register sopno i;
1553 
1554 	/* avoid making error situations worse */
1555 	if (p->error != 0)
1556 		return;
1557 
1558 	/* find the longest OCHAR sequence in strip */
1559 	newlen = 0;
1560 	scan = g->strip + 1;
1561 	do {
1562 		s = *scan++;
1563 		switch (OP(s)) {
1564 		case OCHAR:		/* sequence member */
1565 			if (newlen == 0)		/* new sequence */
1566 				newstart = scan - 1;
1567 			newlen++;
1568 			break;
1569 		case OPLUS_:		/* things that don't break one */
1570 		case OLPAREN:
1571 		case ORPAREN:
1572 			break;
1573 		case OQUEST_:		/* things that must be skipped */
1574 		case OCH_:
1575 			scan--;
1576 			do {
1577 				scan += OPND(s);
1578 				s = *scan;
1579 				/* assert() interferes w debug printouts */
1580 				if (OP(s) != O_QUEST && OP(s) != O_CH &&
1581 							OP(s) != OOR2) {
1582 					g->iflags |= BAD;
1583 					return;
1584 				}
1585 			} while (OP(s) != O_QUEST && OP(s) != O_CH);
1586 			/* fallthrough */
1587 		default:		/* things that break a sequence */
1588 			if (newlen > g->mlen) {		/* ends one */
1589 				start = newstart;
1590 				g->mlen = newlen;
1591 			}
1592 			newlen = 0;
1593 			break;
1594 		}
1595 	} while (OP(s) != OEND);
1596 
1597 	if (g->mlen == 0)		/* there isn't one */
1598 		return;
1599 
1600 	/* turn it into a character string */
1601 	g->must = malloc((size_t)g->mlen + 1);
1602 	if (g->must == NULL) {		/* argh; just forget it */
1603 		g->mlen = 0;
1604 		return;
1605 	}
1606 	cp = g->must;
1607 	scan = start;
1608 	for (i = g->mlen; i > 0; i--) {
1609 		while (OP(s = *scan++) != OCHAR)
1610 			continue;
1611 		assert(cp < g->must + g->mlen);
1612 		*cp++ = (char)OPND(s);
1613 	}
1614 	assert(cp == g->must + g->mlen);
1615 	*cp++ = '\0';		/* just on general principles */
1616 }
1617 
1618 /*
1619  - pluscount - count + nesting
1620  == static sopno pluscount(register struct parse *p, register struct re_guts *g);
1621  */
1622 static sopno			/* nesting depth */
pluscount(p,g)1623 pluscount(p, g)
1624 struct parse *p;
1625 register struct re_guts *g;
1626 {
1627 	register sop *scan;
1628 	register sop s;
1629 	register sopno plusnest = 0;
1630 	register sopno maxnest = 0;
1631 
1632 	if (p->error != 0)
1633 		return(0);	/* there may not be an OEND */
1634 
1635 	scan = g->strip + 1;
1636 	do {
1637 		s = *scan++;
1638 		switch (OP(s)) {
1639 		case OPLUS_:
1640 			plusnest++;
1641 			break;
1642 		case O_PLUS:
1643 			if (plusnest > maxnest)
1644 				maxnest = plusnest;
1645 			plusnest--;
1646 			break;
1647 		}
1648 	} while (OP(s) != OEND);
1649 	if (plusnest != 0)
1650 		g->iflags |= BAD;
1651 	return(maxnest);
1652 }
1653