xref: /freebsd/contrib/nvi/regex/regcomp.c (revision 7661de35d15f582ab33e3bd6b8d909601557e436)
1 /*	$NetBSD: regcomp.c,v 1.7 2011/11/19 17:45:11 tnozaki 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 of the University of Toronto.
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. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the University of
22  *	California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *	@(#)regcomp.c	8.4 (Berkeley) 3/19/94
40  */
41 
42 #if defined(LIBC_SCCS) && !defined(lint)
43 static char sccsid[] = "@(#)regcomp.c	8.4 (Berkeley) 3/19/94";
44 #endif /* LIBC_SCCS and not lint */
45 
46 #include <sys/types.h>
47 #include <stdio.h>
48 #include <string.h>
49 #include <ctype.h>
50 #include <limits.h>
51 #include <stdlib.h>
52 #include <regex.h>
53 
54 #include "utils.h"
55 #include "regex2.h"
56 
57 #include "cclass.h"
58 #include "cname.h"
59 
60 /*
61  * parse structure, passed up and down to avoid global variables and
62  * other clumsinesses
63  */
64 struct parse {
65 	RCHAR_T *next;		/* next character in RE */
66 	RCHAR_T *end;		/* end of string (-> NUL normally) */
67 	int error;		/* has an error been seen? */
68 	sop *strip;		/* malloced strip */
69 	RCHAR_T *stripdata;	/* malloced stripdata */
70 	sopno ssize;		/* malloced strip size (allocated) */
71 	sopno slen;		/* malloced strip length (used) */
72 	int ncsalloc;		/* number of csets allocated */
73 	struct re_guts *g;
74 #	define	NPAREN	10	/* we need to remember () 1-9 for back refs */
75 	sopno pbegin[NPAREN];	/* -> ( ([0] unused) */
76 	sopno pend[NPAREN];	/* -> ) ([0] unused) */
77 };
78 
79 /* ========= begin header generated by ./mkh ========= */
80 #ifdef __cplusplus
81 extern "C" {
82 #endif
83 
84 /* === regcomp.c === */
85 static void p_ere __P((struct parse *p, int stop, size_t reclimit));
86 static void p_ere_exp __P((struct parse *p, size_t reclimit));
87 static void p_str __P((struct parse *p));
88 static void p_bre __P((struct parse *p, int end1, int end2, size_t reclimit));
89 static int p_simp_re __P((struct parse *p, int starordinary, size_t reclimit));
90 static int p_count __P((struct parse *p));
91 static void p_bracket __P((struct parse *p));
92 static void p_b_term __P((struct parse *p, cset *cs));
93 static void p_b_cclass __P((struct parse *p, cset *cs));
94 static void p_b_eclass __P((struct parse *p, cset *cs));
95 static char p_b_symbol __P((struct parse *p));
96 static char p_b_coll_elem __P((struct parse *p, int endc));
97 static char othercase __P((int ch));
98 static void bothcases __P((struct parse *p, int ch));
99 static void ordinary __P((struct parse *p, int ch));
100 static void nonnewline __P((struct parse *p));
101 static void repeat __P((struct parse *p, sopno start, int from, int to, size_t reclimit));
102 static int seterr __P((struct parse *p, int e));
103 static cset *allocset __P((struct parse *p));
104 static void freeset __P((struct parse *p, cset *cs));
105 static int freezeset __P((struct parse *p, cset *cs));
106 static int firstch __P((struct parse *p, cset *cs));
107 static int nch __P((struct parse *p, cset *cs));
108 static void mcadd __P((struct parse *p, cset *cs, const char *cp));
109 #ifdef notdef
110 static void mcsub __P((cset *cs, char *cp));
111 static int mcin __P((cset *cs, char *cp));
112 static char *mcfind __P((cset *cs, char *cp));
113 #endif
114 static void mcinvert __P((struct parse *p, cset *cs));
115 static void mccase __P((struct parse *p, cset *cs));
116 #ifdef notdef
117 static int isinsets __P((struct re_guts *g, int c));
118 static int samesets __P((struct re_guts *g, int c1, int c2));
119 #endif
120 static void categorize __P((struct parse *p, struct re_guts *g));
121 static sopno dupl __P((struct parse *p, sopno start, sopno finish));
122 static void doemit __P((struct parse *p, sop op, size_t opnd));
123 static void doinsert __P((struct parse *p, sop op, size_t opnd, sopno pos));
124 static void dofwd __P((struct parse *p, sopno pos, sop value));
125 static int enlarge __P((struct parse *p, sopno size));
126 static void stripsnug __P((struct parse *p, struct re_guts *g));
127 static void findmust __P((struct parse *p, struct re_guts *g));
128 static sopno pluscount __P((struct parse *p, struct re_guts *g));
129 
130 #ifdef __cplusplus
131 }
132 #endif
133 /* ========= end header generated by ./mkh ========= */
134 
135 static RCHAR_T nuls[10];		/* place to point scanner in event of error */
136 
137 /*
138  * macros for use with parse structure
139  * BEWARE:  these know that the parse structure is named `p' !!!
140  */
141 #define	PEEK()	(*p->next)
142 #define	PEEK2()	(*(p->next+1))
143 #define	MORE()	(p->next < p->end)
144 #define	MORE2()	(p->next+1 < p->end)
145 #define	SEE(c)	(MORE() && PEEK() == (c))
146 #define	SEETWO(a, b)	(MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
147 #define	EAT(c)	((SEE(c)) ? (NEXT(), 1) : 0)
148 #define	EATTWO(a, b)	((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
149 #define	NEXT()	(p->next++)
150 #define	NEXT2()	(p->next += 2)
151 #define	NEXTn(n)	(p->next += (n))
152 #define	GETNEXT()	(*p->next++)
153 #define	SETERROR(e)	seterr(p, (e))
154 #define	REQUIRE(co, e)	((co) || SETERROR(e))
155 #define	MUSTSEE(c, e)	(REQUIRE(MORE() && PEEK() == (c), e))
156 #define	MUSTEAT(c, e)	(REQUIRE(MORE() && GETNEXT() == (c), e))
157 #define	MUSTNOTSEE(c, e)	(REQUIRE(!MORE() || PEEK() != (c), e))
158 #define	EMIT(op, sopnd)	doemit(p, (sop)(op), (size_t)(sopnd))
159 #define	INSERT(op, pos)	doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
160 #define	AHEAD(pos)		dofwd(p, pos, HERE()-(pos))
161 #define	ASTERN(sop, pos)	EMIT(sop, HERE()-pos)
162 #define	HERE()		(p->slen)
163 #define	THERE()		(p->slen - 1)
164 #define	THERETHERE()	(p->slen - 2)
165 #define	DROP(n)	(p->slen -= (n))
166 
167 #ifndef NDEBUG
168 static int never = 0;		/* for use in asserts; shuts lint up */
169 #else
170 #define	never	0		/* some <assert.h>s have bugs too */
171 #endif
172 
173 #define	MEMLIMIT	0x8000000
174 #define MEMSIZE(p) \
175 	((p)->ncsalloc / CHAR_BIT * (p)->g->csetsize + \
176 	(p)->ncsalloc * sizeof(cset) + \
177 	(p)->ssize * sizeof(sop))
178 #define	RECLIMIT	256
179 
180 /*
181  - regcomp - interface for parser and compilation
182  = extern int regcomp(regex_t *, const RCHAR_T *, int);
183  = #define	REG_BASIC	0000
184  = #define	REG_EXTENDED	0001
185  = #define	REG_ICASE	0002
186  = #define	REG_NOSUB	0004
187  = #define	REG_NEWLINE	0010
188  = #define	REG_NOSPEC	0020
189  = #define	REG_PEND	0040
190  = #define	REG_DUMP	0200
191  */
192 int				/* 0 success, otherwise REG_something */
193 regcomp(regex_t *preg, const RCHAR_T *pattern, int cflags)
194 {
195 	struct parse pa;
196 	register struct re_guts *g;
197 	register struct parse *p = &pa;
198 	register int i;
199 	register size_t len;
200 #ifdef REDEBUG
201 #	define	GOODFLAGS(f)	(f)
202 #else
203 #	define	GOODFLAGS(f)	((f)&~REG_DUMP)
204 #endif
205 
206 	cflags = GOODFLAGS(cflags);
207 	if ((cflags&REG_EXTENDED) && (cflags&REG_NOSPEC))
208 		return(REG_INVARG);
209 
210 	if (cflags&REG_PEND) {
211 		if (preg->re_endp < pattern)
212 			return(REG_INVARG);
213 		len = preg->re_endp - pattern;
214 	} else
215 		len = STRLEN(pattern);
216 
217 	/* do the mallocs early so failure handling is easy */
218 	g = (struct re_guts *)malloc(sizeof(struct re_guts) +
219 							(NC-1)*sizeof(cat_t));
220 	if (g == NULL)
221 		return(REG_ESPACE);
222 	p->ssize = len/(size_t)2*(size_t)3 + (size_t)1;	/* ugh */
223 	p->strip = (sop *)malloc(p->ssize * sizeof(sop));
224 	if (p->strip == NULL) {
225 		free((char *)g);
226 		return(REG_ESPACE);
227 	}
228 	p->stripdata = (RCHAR_T *)malloc(p->ssize * sizeof(RCHAR_T));
229 	if (p->stripdata == NULL) {
230 		free((char *)p->strip);
231 		free((char *)g);
232 		return(REG_ESPACE);
233 	}
234 	p->slen = 0;
235 
236 	/* set things up */
237 	p->g = g;
238 	p->next = (RCHAR_T *)pattern;	/* convenience; we do not modify it */
239 	p->end = p->next + len;
240 	p->error = 0;
241 	p->ncsalloc = 0;
242 	for (i = 0; i < NPAREN; i++) {
243 		p->pbegin[i] = 0;
244 		p->pend[i] = 0;
245 	}
246 	g->csetsize = NC;
247 	g->sets = NULL;
248 	g->setbits = NULL;
249 	g->ncsets = 0;
250 	g->cflags = cflags;
251 	g->iflags = 0;
252 	g->nbol = 0;
253 	g->neol = 0;
254 	g->must = NULL;
255 	g->mlen = 0;
256 	g->nsub = 0;
257 #if 0
258 	g->ncategories = 1;	/* category 0 is "everything else" */
259 	g->categories = &g->catspace[-(CHAR_MIN)];
260 	(void) memset((char *)g->catspace, 0, NC*sizeof(cat_t));
261 #endif
262 	g->backrefs = 0;
263 
264 	/* do it */
265 	EMIT(OEND, 0);
266 	g->firststate = THERE();
267 	if (cflags&REG_EXTENDED)
268 		p_ere(p, OUT, 0);
269 	else if (cflags&REG_NOSPEC)
270 		p_str(p);
271 	else
272 		p_bre(p, OUT, OUT, 0);
273 	EMIT(OEND, 0);
274 	g->laststate = THERE();
275 
276 	/* tidy up loose ends and fill things in */
277 	categorize(p, g);
278 	stripsnug(p, g);
279 	findmust(p, g);
280 	g->nplus = pluscount(p, g);
281 	g->magic = MAGIC2;
282 	preg->re_nsub = g->nsub;
283 	preg->re_g = g;
284 	preg->re_magic = MAGIC1;
285 #ifndef REDEBUG
286 	/* not debugging, so can't rely on the assert() in regexec() */
287 	if (g->iflags&BAD)
288 		SETERROR(REG_ASSERT);
289 #endif
290 
291 	/* win or lose, we're done */
292 	if (p->error != 0)	/* lose */
293 		regfree(preg);
294 	return(p->error);
295 }
296 
297 /*
298  - p_ere - ERE parser top level, concatenation and alternation
299  == static void p_ere(register struct parse *p, int stop, size_t reclimit);
300  */
301 static void
302 p_ere(register struct parse *p, int stop, size_t reclimit)
303 
304          			/* character this ERE should end at */
305 {
306 	register char c;
307 	register sopno prevback = 0;
308 	register sopno prevfwd = 0;
309 	register sopno conc;
310 	register int first = 1;		/* is this the first alternative? */
311 
312 	if (reclimit++ > RECLIMIT || p->error == REG_ESPACE) {
313 		p->error = REG_ESPACE;
314 		return;
315 	}
316 
317 	for (;;) {
318 		/* do a bunch of concatenated expressions */
319 		conc = HERE();
320 		while (MORE() && (c = PEEK()) != '|' && c != stop)
321 			p_ere_exp(p, reclimit);
322 		(void)REQUIRE(HERE() != conc, REG_EMPTY);	/* require nonempty */
323 
324 		if (!EAT('|'))
325 			break;		/* NOTE BREAK OUT */
326 
327 		if (first) {
328 			INSERT(OCH_, conc);	/* offset is wrong */
329 			prevfwd = conc;
330 			prevback = conc;
331 			first = 0;
332 		}
333 		ASTERN(OOR1, prevback);
334 		prevback = THERE();
335 		AHEAD(prevfwd);			/* fix previous offset */
336 		prevfwd = HERE();
337 		EMIT(OOR2, 0);			/* offset is very wrong */
338 	}
339 
340 	if (!first) {		/* tail-end fixups */
341 		AHEAD(prevfwd);
342 		ASTERN(O_CH, prevback);
343 	}
344 
345 	assert(!MORE() || SEE(stop));
346 }
347 
348 /*
349  - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
350  == static void p_ere_exp(register struct parse *p);
351  */
352 static void
353 p_ere_exp(register struct parse *p, size_t reclimit)
354 {
355 	register char c;
356 	register sopno pos;
357 	register int count;
358 	register int count2;
359 	register sopno subno;
360 	int wascaret = 0;
361 
362 	assert(MORE());		/* caller should have ensured this */
363 	c = GETNEXT();
364 
365 	pos = HERE();
366 	switch (c) {
367 	case '(':
368 		(void)REQUIRE(MORE(), REG_EPAREN);
369 		p->g->nsub++;
370 		subno = p->g->nsub;
371 		if (subno < NPAREN)
372 			p->pbegin[subno] = HERE();
373 		EMIT(OLPAREN, subno);
374 		if (!SEE(')'))
375 			p_ere(p, ')', reclimit);
376 		if (subno < NPAREN) {
377 			p->pend[subno] = HERE();
378 			assert(p->pend[subno] != 0);
379 		}
380 		EMIT(ORPAREN, subno);
381 		(void)MUSTEAT(')', REG_EPAREN);
382 		break;
383 #ifndef POSIX_MISTAKE
384 	case ')':		/* happens only if no current unmatched ( */
385 		/*
386 		 * You may ask, why the ifndef?  Because I didn't notice
387 		 * this until slightly too late for 1003.2, and none of the
388 		 * other 1003.2 regular-expression reviewers noticed it at
389 		 * all.  So an unmatched ) is legal POSIX, at least until
390 		 * we can get it fixed.
391 		 */
392 		SETERROR(REG_EPAREN);
393 		break;
394 #endif
395 	case '^':
396 		EMIT(OBOL, 0);
397 		p->g->iflags |= USEBOL;
398 		p->g->nbol++;
399 		wascaret = 1;
400 		break;
401 	case '$':
402 		EMIT(OEOL, 0);
403 		p->g->iflags |= USEEOL;
404 		p->g->neol++;
405 		break;
406 	case '|':
407 		SETERROR(REG_EMPTY);
408 		break;
409 	case '*':
410 	case '+':
411 	case '?':
412 		SETERROR(REG_BADRPT);
413 		break;
414 	case '.':
415 		if (p->g->cflags&REG_NEWLINE)
416 			nonnewline(p);
417 		else
418 			EMIT(OANY, 0);
419 		break;
420 	case '[':
421 		p_bracket(p);
422 		break;
423 	case '\\':
424 		(void)REQUIRE(MORE(), REG_EESCAPE);
425 		c = GETNEXT();
426 		ordinary(p, c);
427 		break;
428 	case '{':		/* okay as ordinary except if digit follows */
429 		(void)REQUIRE(!MORE() || !ISDIGIT((UCHAR_T)PEEK()), REG_BADRPT);
430 		/* FALLTHROUGH */
431 	default:
432 		ordinary(p, c);
433 		break;
434 	}
435 
436 	if (!MORE())
437 		return;
438 	c = PEEK();
439 	/* we call { a repetition if followed by a digit */
440 	if (!( c == '*' || c == '+' || c == '?' ||
441 				(c == '{' && MORE2() && ISDIGIT((UCHAR_T)PEEK2())) ))
442 		return;		/* no repetition, we're done */
443 	NEXT();
444 
445 	(void)REQUIRE(!wascaret, REG_BADRPT);
446 	switch (c) {
447 	case '*':	/* implemented as +? */
448 		/* this case does not require the (y|) trick, noKLUDGE */
449 		INSERT(OPLUS_, pos);
450 		ASTERN(O_PLUS, pos);
451 		INSERT(OQUEST_, pos);
452 		ASTERN(O_QUEST, pos);
453 		break;
454 	case '+':
455 		INSERT(OPLUS_, pos);
456 		ASTERN(O_PLUS, pos);
457 		break;
458 	case '?':
459 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
460 		INSERT(OCH_, pos);		/* offset slightly wrong */
461 		ASTERN(OOR1, pos);		/* this one's right */
462 		AHEAD(pos);			/* fix the OCH_ */
463 		EMIT(OOR2, 0);			/* offset very wrong... */
464 		AHEAD(THERE());			/* ...so fix it */
465 		ASTERN(O_CH, THERETHERE());
466 		break;
467 	case '{':
468 		count = p_count(p);
469 		if (EAT(',')) {
470 			if (ISDIGIT((UCHAR_T)PEEK())) {
471 				count2 = p_count(p);
472 				(void)REQUIRE(count <= count2, REG_BADBR);
473 			} else		/* single number with comma */
474 				count2 = INFINITY;
475 		} else		/* just a single number */
476 			count2 = count;
477 		repeat(p, pos, count, count2, 0);
478 		if (!EAT('}')) {	/* error heuristics */
479 			while (MORE() && PEEK() != '}')
480 				NEXT();
481 			(void)REQUIRE(MORE(), REG_EBRACE);
482 			SETERROR(REG_BADBR);
483 		}
484 		break;
485 	}
486 
487 	if (!MORE())
488 		return;
489 	c = PEEK();
490 	if (!( c == '*' || c == '+' || c == '?' ||
491 				(c == '{' && MORE2() && ISDIGIT((UCHAR_T)PEEK2())) ) )
492 		return;
493 	SETERROR(REG_BADRPT);
494 }
495 
496 /*
497  - p_str - string (no metacharacters) "parser"
498  == static void p_str(register struct parse *p);
499  */
500 static void
501 p_str(register struct parse *p)
502 {
503 	(void)REQUIRE(MORE(), REG_EMPTY);
504 	while (MORE())
505 		ordinary(p, GETNEXT());
506 }
507 
508 /*
509  - p_bre - BRE parser top level, anchoring and concatenation
510  == static void p_bre(register struct parse *p, register int end1, \
511  ==	register int end2, size_t reclimit);
512  * Giving end1 as OUT essentially eliminates the end1/end2 check.
513  *
514  * This implementation is a bit of a kludge, in that a trailing $ is first
515  * taken as an ordinary character and then revised to be an anchor.  The
516  * only undesirable side effect is that '$' gets included as a character
517  * category in such cases.  This is fairly harmless; not worth fixing.
518  * The amount of lookahead needed to avoid this kludge is excessive.
519  */
520 static void
521 p_bre(register struct parse *p, register int end1, register int end2, size_t reclimit)
522 
523                   		/* first terminating character */
524                   		/* second terminating character */
525 {
526 	register sopno start;
527 	register int first = 1;			/* first subexpression? */
528 	register int wasdollar = 0;
529 
530 	if (reclimit++ > RECLIMIT || p->error == REG_ESPACE) {
531 		p->error = REG_ESPACE;
532 		return;
533 	}
534 
535 	start = HERE();
536 
537 	if (EAT('^')) {
538 		EMIT(OBOL, 0);
539 		p->g->iflags |= USEBOL;
540 		p->g->nbol++;
541 	}
542 	while (MORE() && !SEETWO(end1, end2)) {
543 		wasdollar = p_simp_re(p, first, reclimit);
544 		first = 0;
545 	}
546 	if (wasdollar) {	/* oops, that was a trailing anchor */
547 		DROP(1);
548 		EMIT(OEOL, 0);
549 		p->g->iflags |= USEEOL;
550 		p->g->neol++;
551 	}
552 
553 	(void)REQUIRE(HERE() != start, REG_EMPTY);	/* require nonempty */
554 }
555 
556 /*
557  - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
558  == static int p_simp_re(register struct parse *p, int starordinary, size_t reclimit);
559  */
560 static int			/* was the simple RE an unbackslashed $? */
561 p_simp_re(register struct parse *p, int starordinary, size_t reclimit)
562 
563                  		/* is a leading * an ordinary character? */
564 {
565 	register int c;
566 	register int count;
567 	register int count2;
568 	register sopno pos;
569 	register int i;
570 	register sopno subno;
571 	int backsl;
572 
573 	pos = HERE();		/* repetion op, if any, covers from here */
574 
575 	assert(MORE());		/* caller should have ensured this */
576 	c = GETNEXT();
577 	backsl = c == '\\';
578 	if (backsl) {
579 		(void)REQUIRE(MORE(), REG_EESCAPE);
580 		c = (unsigned char)GETNEXT();
581 		switch (c) {
582 		case '{':
583 			SETERROR(REG_BADRPT);
584 			break;
585 		case '(':
586 			p->g->nsub++;
587 			subno = p->g->nsub;
588 			if (subno < NPAREN)
589 				p->pbegin[subno] = HERE();
590 			EMIT(OLPAREN, subno);
591 			/* the MORE here is an error heuristic */
592 			if (MORE() && !SEETWO('\\', ')'))
593 				p_bre(p, '\\', ')', reclimit);
594 			if (subno < NPAREN) {
595 				p->pend[subno] = HERE();
596 				assert(p->pend[subno] != 0);
597 			}
598 			EMIT(ORPAREN, subno);
599 			(void)REQUIRE(EATTWO('\\', ')'), REG_EPAREN);
600 			break;
601 		case ')':	/* should not get here -- must be user */
602 		case '}':
603 			SETERROR(REG_EPAREN);
604 			break;
605 		case '1':
606 		case '2':
607 		case '3':
608 		case '4':
609 		case '5':
610 		case '6':
611 		case '7':
612 		case '8':
613 		case '9':
614 			i = c - '0';
615 			assert(i < NPAREN);
616 			if (p->pend[i] != 0) {
617 				assert(i <= p->g->nsub);
618 				EMIT(OBACK_, i);
619 				assert(p->pbegin[i] != 0);
620 				assert(p->strip[p->pbegin[i]] == OLPAREN);
621 				assert(p->strip[p->pend[i]] == ORPAREN);
622 				(void) dupl(p, p->pbegin[i]+1, p->pend[i]);
623 				EMIT(O_BACK, i);
624 			} else
625 				SETERROR(REG_ESUBREG);
626 			p->g->backrefs = 1;
627 			break;
628 		default:
629 			ordinary(p, c);
630 			break;
631 		}
632 	} else {
633 		switch (c) {
634 		case '.':
635 			if (p->g->cflags&REG_NEWLINE)
636 				nonnewline(p);
637 			else
638 				EMIT(OANY, 0);
639 			break;
640 		case '[':
641 			p_bracket(p);
642 			break;
643 		case '*':
644 			(void)REQUIRE(starordinary, REG_BADRPT);
645 			/* FALLTHROUGH */
646 		default:
647 			ordinary(p, c);
648 			break;
649 		}
650 	}
651 
652 	if (EAT('*')) {		/* implemented as +? */
653 		/* this case does not require the (y|) trick, noKLUDGE */
654 		INSERT(OPLUS_, pos);
655 		ASTERN(O_PLUS, pos);
656 		INSERT(OQUEST_, pos);
657 		ASTERN(O_QUEST, pos);
658 	} else if (EATTWO('\\', '{')) {
659 		count = p_count(p);
660 		if (EAT(',')) {
661 			if (MORE() && ISDIGIT((UCHAR_T)PEEK())) {
662 				count2 = p_count(p);
663 				(void)REQUIRE(count <= count2, REG_BADBR);
664 			} else		/* single number with comma */
665 				count2 = INFINITY;
666 		} else		/* just a single number */
667 			count2 = count;
668 		repeat(p, pos, count, count2, reclimit);
669 		if (!EATTWO('\\', '}')) {	/* error heuristics */
670 			while (MORE() && !SEETWO('\\', '}'))
671 				NEXT();
672 			(void)REQUIRE(MORE(), REG_EBRACE);
673 			SETERROR(REG_BADBR);
674 		}
675 	} else if (!backsl && c == (unsigned char)'$')	/* $ (but not \$) ends it */
676 		return(1);
677 
678 	return(0);
679 }
680 
681 /*
682  - p_count - parse a repetition count
683  == static int p_count(register struct parse *p);
684  */
685 static int			/* the value */
686 p_count(register struct parse *p)
687 {
688 	register int count = 0;
689 	register int ndigits = 0;
690 
691 	while (MORE() && ISDIGIT((UCHAR_T)PEEK()) && count <= DUPMAX) {
692 		count = count*10 + (GETNEXT() - '0');
693 		ndigits++;
694 	}
695 
696 	(void)REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
697 	return(count);
698 }
699 
700 /*
701  - p_bracket - parse a bracketed character list
702  == static void p_bracket(register struct parse *p);
703  *
704  * Note a significant property of this code:  if the allocset() did SETERROR,
705  * no set operations are done.
706  */
707 static void
708 p_bracket(register struct parse *p)
709 {
710 	register cset *cs;
711 	register int invert = 0;
712 	static RCHAR_T bow[] = { '[', ':', '<', ':', ']', ']' };
713 	static RCHAR_T eow[] = { '[', ':', '>', ':', ']', ']' };
714 
715 	cs = allocset(p);
716 	if (cs == NULL)
717 		return;
718 
719 	/* Dept of Truly Sickening Special-Case Kludges */
720 	if (p->next + 5 < p->end && MEMCMP(p->next, bow, 6) == 0) {
721 		EMIT(OBOW, 0);
722 		NEXTn(6);
723 		return;
724 	}
725 	if (p->next + 5 < p->end && MEMCMP(p->next, eow, 6) == 0) {
726 		EMIT(OEOW, 0);
727 		NEXTn(6);
728 		return;
729 	}
730 
731 	if (EAT('^'))
732 		invert++;	/* make note to invert set at end */
733 	if (EAT(']'))
734 		CHadd(cs, ']');
735 	else if (EAT('-'))
736 		CHadd(cs, '-');
737 	while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
738 		p_b_term(p, cs);
739 	if (EAT('-'))
740 		CHadd(cs, '-');
741 	(void)MUSTEAT(']', REG_EBRACK);
742 
743 	if (p->error != 0)	/* don't mess things up further */
744 		return;
745 
746 	if (p->g->cflags&REG_ICASE) {
747 		register int i;
748 		register int ci;
749 
750 		for (i = p->g->csetsize - 1; i >= 0; i--)
751 			if (CHIN(cs, i) && isalpha(i)) {
752 				ci = othercase(i);
753 				if (ci != i)
754 					CHadd(cs, ci);
755 			}
756 		if (cs->multis != NULL)
757 			mccase(p, cs);
758 	}
759 	if (invert) {
760 		register int i;
761 
762 		for (i = p->g->csetsize - 1; i >= 0; i--)
763 			if (CHIN(cs, i))
764 				CHsub(cs, i);
765 			else
766 				CHadd(cs, i);
767 		if (p->g->cflags&REG_NEWLINE)
768 			CHsub(cs, '\n');
769 		if (cs->multis != NULL)
770 			mcinvert(p, cs);
771 	}
772 
773 	assert(cs->multis == NULL);		/* xxx */
774 
775 	if (nch(p, cs) == 1) {		/* optimize singleton sets */
776 		ordinary(p, firstch(p, cs));
777 		freeset(p, cs);
778 	} else
779 		EMIT(OANYOF, freezeset(p, cs));
780 }
781 
782 /*
783  - p_b_term - parse one term of a bracketed character list
784  == static void p_b_term(register struct parse *p, register cset *cs);
785  */
786 static void
787 p_b_term(register struct parse *p, register cset *cs)
788 {
789 	register char c;
790 	register char start, finish;
791 	register int i;
792 
793 	/* classify what we've got */
794 	switch ((MORE()) ? PEEK() : '\0') {
795 	case '[':
796 		c = (MORE2()) ? PEEK2() : '\0';
797 		break;
798 	case '-':
799 		SETERROR(REG_ERANGE);
800 		return;			/* NOTE RETURN */
801 		break;
802 	default:
803 		c = '\0';
804 		break;
805 	}
806 
807 	switch (c) {
808 	case ':':		/* character class */
809 		NEXT2();
810 		(void)REQUIRE(MORE(), REG_EBRACK);
811 		c = PEEK();
812 		(void)REQUIRE(c != '-' && c != ']', REG_ECTYPE);
813 		p_b_cclass(p, cs);
814 		(void)REQUIRE(MORE(), REG_EBRACK);
815 		(void)REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
816 		break;
817 	case '=':		/* equivalence class */
818 		NEXT2();
819 		(void)REQUIRE(MORE(), REG_EBRACK);
820 		c = PEEK();
821 		(void)REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
822 		p_b_eclass(p, cs);
823 		(void)REQUIRE(MORE(), REG_EBRACK);
824 		(void)REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
825 		break;
826 	default:		/* symbol, ordinary character, or range */
827 /* xxx revision needed for multichar stuff */
828 		start = p_b_symbol(p);
829 		if (SEE('-') && MORE2() && PEEK2() != ']') {
830 			/* range */
831 			NEXT();
832 			if (EAT('-'))
833 				finish = '-';
834 			else
835 				finish = p_b_symbol(p);
836 		} else
837 			finish = start;
838 /* xxx what about signed chars here... */
839 		(void)REQUIRE(start <= finish, REG_ERANGE);
840 		for (i = start; i <= finish; i++)
841 			CHadd(cs, i);
842 		break;
843 	}
844 }
845 
846 /*
847  - p_b_cclass - parse a character-class name and deal with it
848  == static void p_b_cclass(register struct parse *p, register cset *cs);
849  */
850 static void
851 p_b_cclass(register struct parse *p, register cset *cs)
852 {
853 	register RCHAR_T *sp = p->next;
854 	register struct cclass *cp;
855 	register size_t len;
856 	register const char *u;
857 	register char c;
858 
859 	while (MORE() && isalpha(PEEK()))
860 		NEXT();
861 	len = p->next - sp;
862 	for (cp = cclasses; cp->name != NULL; cp++)
863 		if (STRLEN(cp->name) == len && !MEMCMP(cp->name, sp, len))
864 			break;
865 	if (cp->name == NULL) {
866 		/* oops, didn't find it */
867 		SETERROR(REG_ECTYPE);
868 		return;
869 	}
870 
871 	u = cp->chars;
872 	while ((c = *u++) != '\0')
873 		CHadd(cs, c);
874 	for (u = cp->multis; *u != '\0'; u += strlen(u) + 1)
875 		MCadd(p, cs, u);
876 }
877 
878 /*
879  - p_b_eclass - parse an equivalence-class name and deal with it
880  == static void p_b_eclass(register struct parse *p, register cset *cs);
881  *
882  * This implementation is incomplete. xxx
883  */
884 static void
885 p_b_eclass(register struct parse *p, register cset *cs)
886 {
887 	register char c;
888 
889 	c = p_b_coll_elem(p, '=');
890 	CHadd(cs, c);
891 }
892 
893 /*
894  - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
895  == static char p_b_symbol(register struct parse *p);
896  */
897 static char			/* value of symbol */
898 p_b_symbol(register struct parse *p)
899 {
900 	register char value;
901 
902 	(void)REQUIRE(MORE(), REG_EBRACK);
903 	if (!EATTWO('[', '.'))
904 		return(GETNEXT());
905 
906 	/* collating symbol */
907 	value = p_b_coll_elem(p, '.');
908 	(void)REQUIRE(EATTWO('.', ']'), REG_ECOLLATE);
909 	return(value);
910 }
911 
912 /*
913  - p_b_coll_elem - parse a collating-element name and look it up
914  == static char p_b_coll_elem(register struct parse *p, int endc);
915  */
916 static char			/* value of collating element */
917 p_b_coll_elem(register struct parse *p, int endc)
918 
919          			/* name ended by endc,']' */
920 {
921 	register RCHAR_T *sp = p->next;
922 	register struct cname *cp;
923 	register size_t len;
924 
925 	while (MORE() && !SEETWO(endc, ']'))
926 		NEXT();
927 	if (!MORE()) {
928 		SETERROR(REG_EBRACK);
929 		return(0);
930 	}
931 	len = p->next - sp;
932 	for (cp = cnames; cp->name != NULL; cp++)
933 		if (STRLEN(cp->name) == len && MEMCMP(cp->name, sp, len))
934 			return(cp->code);	/* known name */
935 	if (len == 1)
936 		return(*sp);	/* single character */
937 	SETERROR(REG_ECOLLATE);			/* neither */
938 	return(0);
939 }
940 
941 /*
942  - othercase - return the case counterpart of an alphabetic
943  == static char othercase(int ch);
944  */
945 static char			/* if no counterpart, return ch */
946 othercase(int ch)
947 {
948 	assert(isalpha(ch));
949 	if (isupper(ch))
950 		return(tolower(ch));
951 	else if (islower(ch))
952 		return(toupper(ch));
953 	else			/* peculiar, but could happen */
954 		return(ch);
955 }
956 
957 /*
958  - bothcases - emit a dualcase version of a two-case character
959  == static void bothcases(register struct parse *p, int ch);
960  *
961  * Boy, is this implementation ever a kludge...
962  */
963 static void
964 bothcases(register struct parse *p, int ch)
965 {
966 	register RCHAR_T *oldnext = p->next;
967 	register RCHAR_T *oldend = p->end;
968 	RCHAR_T bracket[3];
969 
970 	assert(othercase(ch) != ch);	/* p_bracket() would recurse */
971 	p->next = bracket;
972 	p->end = bracket+2;
973 	bracket[0] = ch;
974 	bracket[1] = ']';
975 	bracket[2] = '\0';
976 	p_bracket(p);
977 	assert(p->next == bracket+2);
978 	p->next = oldnext;
979 	p->end = oldend;
980 }
981 
982 /*
983  - ordinary - emit an ordinary character
984  == static void ordinary(register struct parse *p, register int ch);
985  */
986 static void
987 ordinary(register struct parse *p, register int ch)
988 {
989 /*
990 	register cat_t *cap = p->g->categories;
991 */
992 
993 	if ((p->g->cflags&REG_ICASE) && isalpha(ch) && othercase(ch) != ch)
994 		bothcases(p, ch);
995 	else {
996 		EMIT(OCHAR, (UCHAR_T)ch);
997 /*
998 		if (cap[ch] == 0)
999 			cap[ch] = p->g->ncategories++;
1000 */
1001 	}
1002 }
1003 
1004 /*
1005  - nonnewline - emit REG_NEWLINE version of OANY
1006  == static void nonnewline(register struct parse *p);
1007  *
1008  * Boy, is this implementation ever a kludge...
1009  */
1010 static void
1011 nonnewline(register struct parse *p)
1012 {
1013 	register RCHAR_T *oldnext = p->next;
1014 	register RCHAR_T *oldend = p->end;
1015 	RCHAR_T bracket[4];
1016 
1017 	p->next = bracket;
1018 	p->end = bracket+3;
1019 	bracket[0] = '^';
1020 	bracket[1] = '\n';
1021 	bracket[2] = ']';
1022 	bracket[3] = '\0';
1023 	p_bracket(p);
1024 	assert(p->next == bracket+3);
1025 	p->next = oldnext;
1026 	p->end = oldend;
1027 }
1028 
1029 /*
1030  - repeat - generate code for a bounded repetition, recursively if needed
1031  == static void repeat(register struct parse *p, sopno start, int from, int to, size_t reclimit);
1032  */
1033 static void
1034 repeat(register struct parse *p, sopno start, int from, int to, size_t reclimit)
1035 
1036             			/* operand from here to end of strip */
1037          			/* repeated from this number */
1038        				/* to this number of times (maybe INFINITY) */
1039 {
1040 	register sopno finish;
1041 #	define	N	2
1042 #	define	INF	3
1043 #	define	REP(f, t)	((f)*8 + (t))
1044 #	define	MAP(n)	(((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N)
1045 	register sopno copy;
1046 
1047 	if (reclimit++ > RECLIMIT)
1048 		p->error = REG_ESPACE;
1049 	if (p->error)
1050 		return;
1051 
1052 	finish = HERE();
1053 
1054 	assert(from <= to);
1055 
1056 	switch (REP(MAP(from), MAP(to))) {
1057 	case REP(0, 0):			/* must be user doing this */
1058 		DROP(finish-start);	/* drop the operand */
1059 		break;
1060 	case REP(0, 1):			/* as x{1,1}? */
1061 	case REP(0, N):			/* as x{1,n}? */
1062 	case REP(0, INF):		/* as x{1,}? */
1063 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
1064 		INSERT(OCH_, start);		/* offset is wrong... */
1065 		repeat(p, start+1, 1, to, reclimit);
1066 		ASTERN(OOR1, start);
1067 		AHEAD(start);			/* ... fix it */
1068 		EMIT(OOR2, 0);
1069 		AHEAD(THERE());
1070 		ASTERN(O_CH, THERETHERE());
1071 		break;
1072 	case REP(1, 1):			/* trivial case */
1073 		/* done */
1074 		break;
1075 	case REP(1, N):			/* as x?x{1,n-1} */
1076 		/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
1077 		INSERT(OCH_, start);
1078 		ASTERN(OOR1, start);
1079 		AHEAD(start);
1080 		EMIT(OOR2, 0);			/* offset very wrong... */
1081 		AHEAD(THERE());			/* ...so fix it */
1082 		ASTERN(O_CH, THERETHERE());
1083 		copy = dupl(p, start+1, finish+1);
1084 		assert(copy == finish+4);
1085 		repeat(p, copy, 1, to-1, reclimit);
1086 		break;
1087 	case REP(1, INF):		/* as x+ */
1088 		INSERT(OPLUS_, start);
1089 		ASTERN(O_PLUS, start);
1090 		break;
1091 	case REP(N, N):			/* as xx{m-1,n-1} */
1092 		copy = dupl(p, start, finish);
1093 		repeat(p, copy, from-1, to-1, reclimit);
1094 		break;
1095 	case REP(N, INF):		/* as xx{n-1,INF} */
1096 		copy = dupl(p, start, finish);
1097 		repeat(p, copy, from-1, to, reclimit);
1098 		break;
1099 	default:			/* "can't happen" */
1100 		SETERROR(REG_ASSERT);	/* just in case */
1101 		break;
1102 	}
1103 }
1104 
1105 /*
1106  - seterr - set an error condition
1107  == static int seterr(register struct parse *p, int e);
1108  */
1109 static int			/* useless but makes type checking happy */
1110 seterr(register struct parse *p, int e)
1111 {
1112 	if (p->error == 0)	/* keep earliest error condition */
1113 		p->error = e;
1114 	p->next = nuls;		/* try to bring things to a halt */
1115 	p->end = nuls;
1116 	return(0);		/* make the return value well-defined */
1117 }
1118 
1119 /*
1120  - allocset - allocate a set of characters for []
1121  == static cset *allocset(register struct parse *p);
1122  */
1123 static cset *
1124 allocset(register struct parse *p)
1125 {
1126 	register int no = p->g->ncsets++;
1127 	register size_t nc;
1128 	register size_t nbytes;
1129 	register cset *cs;
1130 	register size_t css = (size_t)p->g->csetsize;
1131 	register int i;
1132 
1133 	if (no >= p->ncsalloc) {	/* need another column of space */
1134 		p->ncsalloc += CHAR_BIT;
1135 		nc = p->ncsalloc;
1136 		assert(nc % CHAR_BIT == 0);
1137 		nbytes = nc / CHAR_BIT * css;
1138 		if (MEMSIZE(p) > MEMLIMIT)
1139 			goto oomem;
1140 		if (p->g->sets == NULL)
1141 			p->g->sets = (cset *)malloc(nc * sizeof(cset));
1142 		else
1143 			p->g->sets = (cset *)realloc((char *)p->g->sets,
1144 							nc * sizeof(cset));
1145 		if (p->g->setbits == NULL)
1146 			p->g->setbits = (uch *)malloc(nbytes);
1147 		else {
1148 			p->g->setbits = (uch *)realloc((char *)p->g->setbits,
1149 								nbytes);
1150 			/* xxx this isn't right if setbits is now NULL */
1151 			for (i = 0; i < no; i++)
1152 				p->g->sets[i].ptr = p->g->setbits + css*(i/CHAR_BIT);
1153 		}
1154 		if (p->g->sets != NULL && p->g->setbits != NULL)
1155 			(void) memset((char *)p->g->setbits + (nbytes - css),
1156 								0, css);
1157 		else {
1158 oomem:
1159 			no = 0;
1160 			SETERROR(REG_ESPACE);
1161 			/* caller's responsibility not to do set ops */
1162 			return NULL;
1163 		}
1164 	}
1165 
1166 	cs = &p->g->sets[no];
1167 	cs->ptr = p->g->setbits + css*((no)/CHAR_BIT);
1168 	cs->mask = 1 << ((no) % CHAR_BIT);
1169 	cs->hash = 0;
1170 	cs->smultis = 0;
1171 	cs->multis = NULL;
1172 
1173 	return(cs);
1174 }
1175 
1176 /*
1177  - freeset - free a now-unused set
1178  == static void freeset(register struct parse *p, register cset *cs);
1179  */
1180 static void
1181 freeset(register struct parse *p, register cset *cs)
1182 {
1183 	register size_t i;
1184 	register cset *top = &p->g->sets[p->g->ncsets];
1185 	register size_t css = (size_t)p->g->csetsize;
1186 
1187 	for (i = 0; i < css; i++)
1188 		CHsub(cs, i);
1189 	if (cs == top-1)	/* recover only the easy case */
1190 		p->g->ncsets--;
1191 }
1192 
1193 /*
1194  - freezeset - final processing on a set of characters
1195  == static int freezeset(register struct parse *p, register cset *cs);
1196  *
1197  * The main task here is merging identical sets.  This is usually a waste
1198  * of time (although the hash code minimizes the overhead), but can win
1199  * big if REG_ICASE is being used.  REG_ICASE, by the way, is why the hash
1200  * is done using addition rather than xor -- all ASCII [aA] sets xor to
1201  * the same value!
1202  */
1203 static int			/* set number */
1204 freezeset(register struct parse *p, register cset *cs)
1205 {
1206 	register uch h = cs->hash;
1207 	register size_t i;
1208 	register cset *top = &p->g->sets[p->g->ncsets];
1209 	register cset *cs2;
1210 	register size_t css = (size_t)p->g->csetsize;
1211 
1212 	/* look for an earlier one which is the same */
1213 	for (cs2 = &p->g->sets[0]; cs2 < top; cs2++)
1214 		if (cs2->hash == h && cs2 != cs) {
1215 			/* maybe */
1216 			for (i = 0; i < css; i++)
1217 				if (!!CHIN(cs2, i) != !!CHIN(cs, i))
1218 					break;		/* no */
1219 			if (i == css)
1220 				break;			/* yes */
1221 		}
1222 
1223 	if (cs2 < top) {	/* found one */
1224 		freeset(p, cs);
1225 		cs = cs2;
1226 	}
1227 
1228 	return((int)(cs - p->g->sets));
1229 }
1230 
1231 /*
1232  - firstch - return first character in a set (which must have at least one)
1233  == static int firstch(register struct parse *p, register cset *cs);
1234  */
1235 static int			/* character; there is no "none" value */
1236 firstch(register struct parse *p, register cset *cs)
1237 {
1238 	register size_t i;
1239 	register size_t css = (size_t)p->g->csetsize;
1240 
1241 	for (i = 0; i < css; i++)
1242 		if (CHIN(cs, i))
1243 			return((char)i);
1244 	assert(never);
1245 	return(0);		/* arbitrary */
1246 }
1247 
1248 /*
1249  - nch - number of characters in a set
1250  == static int nch(register struct parse *p, register cset *cs);
1251  */
1252 static int
1253 nch(register struct parse *p, register cset *cs)
1254 {
1255 	register size_t i;
1256 	register size_t css = (size_t)p->g->csetsize;
1257 	register int n = 0;
1258 
1259 	for (i = 0; i < css; i++)
1260 		if (CHIN(cs, i))
1261 			n++;
1262 	return(n);
1263 }
1264 
1265 /*
1266  - mcadd - add a collating element to a cset
1267  == static void mcadd(register struct parse *p, register cset *cs, \
1268  ==	register char *cp);
1269  */
1270 static void
1271 mcadd(register struct parse *p, register cset *cs, register const char *cp)
1272 {
1273 	register size_t oldend = cs->smultis;
1274 	void *np;
1275 
1276 	cs->smultis += strlen(cp) + 1;
1277 	np = realloc(cs->multis, cs->smultis);
1278 	if (np == NULL) {
1279 		if (cs->multis)
1280 			free(cs->multis);
1281 		cs->multis = NULL;
1282 		SETERROR(REG_ESPACE);
1283 		return;
1284 	}
1285 	cs->multis = np;
1286 
1287 	(void) strlcpy(cs->multis + oldend - 1, cp, cs->smultis - oldend + 1);
1288 }
1289 
1290 #ifdef notdef
1291 /*
1292  - mcsub - subtract a collating element from a cset
1293  == static void mcsub(register cset *cs, register char *cp);
1294  */
1295 static void
1296 mcsub(register cset *cs, register char *cp)
1297 {
1298 	register char *fp = mcfind(cs, cp);
1299 	register size_t len = strlen(fp);
1300 
1301 	assert(fp != NULL);
1302 	(void) memmove(fp, fp + len + 1,
1303 				cs->smultis - (fp + len + 1 - cs->multis));
1304 	cs->smultis -= len;
1305 
1306 	if (cs->smultis == 0) {
1307 		free(cs->multis);
1308 		cs->multis = NULL;
1309 		return;
1310 	}
1311 
1312 	cs->multis = realloc(cs->multis, cs->smultis);
1313 	assert(cs->multis != NULL);
1314 }
1315 
1316 /*
1317  - mcin - is a collating element in a cset?
1318  == static int mcin(register cset *cs, register char *cp);
1319  */
1320 static int
1321 mcin(register cset *cs, register char *cp)
1322 {
1323 	return(mcfind(cs, cp) != NULL);
1324 }
1325 
1326 /*
1327  - mcfind - find a collating element in a cset
1328  == static char *mcfind(register cset *cs, register char *cp);
1329  */
1330 static char *
1331 mcfind(register cset *cs, register char *cp)
1332 {
1333 	register char *p;
1334 
1335 	if (cs->multis == NULL)
1336 		return(NULL);
1337 	for (p = cs->multis; *p != '\0'; p += strlen(p) + 1)
1338 		if (strcmp(cp, p) == 0)
1339 			return(p);
1340 	return(NULL);
1341 }
1342 #endif
1343 
1344 /*
1345  - mcinvert - invert the list of collating elements in a cset
1346  == static void mcinvert(register struct parse *p, register cset *cs);
1347  *
1348  * This would have to know the set of possibilities.  Implementation
1349  * is deferred.
1350  */
1351 static void
1352 mcinvert(register struct parse *p, register cset *cs)
1353 {
1354 	assert(cs->multis == NULL);	/* xxx */
1355 }
1356 
1357 /*
1358  - mccase - add case counterparts of the list of collating elements in a cset
1359  == static void mccase(register struct parse *p, register cset *cs);
1360  *
1361  * This would have to know the set of possibilities.  Implementation
1362  * is deferred.
1363  */
1364 static void
1365 mccase(register struct parse *p, register cset *cs)
1366 {
1367 	assert(cs->multis == NULL);	/* xxx */
1368 }
1369 
1370 #ifdef notdef
1371 /*
1372  - isinsets - is this character in any sets?
1373  == static int isinsets(register struct re_guts *g, int c);
1374  */
1375 static int			/* predicate */
1376 isinsets(register struct re_guts *g, int c)
1377 {
1378 	register uch *col;
1379 	register int i;
1380 	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
1381 	register unsigned uc = (unsigned char)c;
1382 
1383 	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1384 		if (col[uc] != 0)
1385 			return(1);
1386 	return(0);
1387 }
1388 
1389 /*
1390  - samesets - are these two characters in exactly the same sets?
1391  == static int samesets(register struct re_guts *g, int c1, int c2);
1392  */
1393 static int			/* predicate */
1394 samesets(register struct re_guts *g, int c1, int c2)
1395 {
1396 	register uch *col;
1397 	register int i;
1398 	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
1399 	register unsigned uc1 = (unsigned char)c1;
1400 	register unsigned uc2 = (unsigned char)c2;
1401 
1402 	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
1403 		if (col[uc1] != col[uc2])
1404 			return(0);
1405 	return(1);
1406 }
1407 #endif
1408 
1409 /*
1410  - categorize - sort out character categories
1411  == static void categorize(struct parse *p, register struct re_guts *g);
1412  */
1413 static void
1414 categorize(struct parse *p, register struct re_guts *g)
1415 {
1416 #ifdef notdef
1417 	register cat_t *cats = g->categories;
1418 	register int c;
1419 	register int c2;
1420 	register cat_t cat;
1421 
1422 	/* avoid making error situations worse */
1423 	if (p->error != 0)
1424 		return;
1425 
1426 	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
1427 		if (cats[c] == 0 && isinsets(g, c)) {
1428 			cat = g->ncategories++;
1429 			cats[c] = cat;
1430 			for (c2 = c+1; c2 <= CHAR_MAX; c2++)
1431 				if (cats[c2] == 0 && samesets(g, c, c2))
1432 					cats[c2] = cat;
1433 		}
1434 #endif
1435 }
1436 
1437 /*
1438  - dupl - emit a duplicate of a bunch of sops
1439  == static sopno dupl(register struct parse *p, sopno start, sopno finish);
1440  */
1441 static sopno			/* start of duplicate */
1442 dupl(register struct parse *p, sopno start, sopno finish)
1443 
1444             			/* from here */
1445              			/* to this less one */
1446 {
1447 	register sopno ret = HERE();
1448 	register sopno len = finish - start;
1449 
1450 	assert(finish >= start);
1451 	if (len == 0)
1452 		return(ret);
1453 	if (!enlarge(p, p->ssize + len))	/* this many unexpected additions */
1454 		return ret;
1455 	assert(p->ssize >= p->slen + len);
1456 	(void) memcpy((char *)(p->strip + p->slen),
1457 		(char *)(p->strip + start), (size_t)len*sizeof(sop));
1458 	(void) memcpy((char *)(p->stripdata + p->slen),
1459 		(char *)(p->stripdata + start), (size_t)len*sizeof(RCHAR_T));
1460 	p->slen += len;
1461 	return(ret);
1462 }
1463 
1464 /*
1465  - doemit - emit a strip operator
1466  == static void doemit(register struct parse *p, sop op, size_t opnd);
1467  *
1468  * It might seem better to implement this as a macro with a function as
1469  * hard-case backup, but it's just too big and messy unless there are
1470  * some changes to the data structures.  Maybe later.
1471  */
1472 static void
1473 doemit(register struct parse *p, sop op, size_t opnd)
1474 {
1475 	/* avoid making error situations worse */
1476 	if (p->error != 0)
1477 		return;
1478 
1479 	/* deal with oversize operands ("can't happen", more or less) */
1480 	assert(opnd < 1);
1481 
1482 	/* deal with undersized strip */
1483 	if (p->slen >= p->ssize)
1484 		if (!enlarge(p, (p->ssize+1) / 2 * 3))	/* +50% */
1485 			return;
1486 
1487 	/* finally, it's all reduced to the easy case */
1488 	p->strip[p->slen] = op;
1489 	p->stripdata[p->slen] = opnd;
1490 	p->slen++;
1491 }
1492 
1493 /*
1494  - doinsert - insert a sop into the strip
1495  == static void doinsert(register struct parse *p, sop op, size_t opnd, sopno pos);
1496  */
1497 static void
1498 doinsert(register struct parse *p, sop op, size_t opnd, sopno pos)
1499 {
1500 	register sopno sn;
1501 	register sop s;
1502 	register RCHAR_T d;
1503 	register int i;
1504 
1505 	/* avoid making error situations worse */
1506 	if (p->error != 0)
1507 		return;
1508 
1509 	sn = HERE();
1510 	EMIT(op, opnd);		/* do checks, ensure space */
1511 	assert(HERE() == sn+1);
1512 	s = p->strip[sn];
1513 	d = p->stripdata[sn];
1514 
1515 	/* adjust paren pointers */
1516 	assert(pos > 0);
1517 	for (i = 1; i < NPAREN; i++) {
1518 		if (p->pbegin[i] >= pos) {
1519 			p->pbegin[i]++;
1520 		}
1521 		if (p->pend[i] >= pos) {
1522 			p->pend[i]++;
1523 		}
1524 	}
1525 
1526 	memmove((char *)&p->strip[pos+1], (char *)&p->strip[pos],
1527 						(HERE()-pos-1)*sizeof(sop));
1528 	memmove((char *)&p->stripdata[pos+1], (char *)&p->stripdata[pos],
1529 						(HERE()-pos-1)*sizeof(RCHAR_T));
1530 	p->strip[pos] = s;
1531 	p->stripdata[pos] = d;
1532 }
1533 
1534 /*
1535  - dofwd - complete a forward reference
1536  == static void dofwd(register struct parse *p, sopno pos, sop value);
1537  */
1538 static void
1539 dofwd(register struct parse *p, register sopno pos, sop value)
1540 {
1541 	/* avoid making error situations worse */
1542 	if (p->error != 0)
1543 		return;
1544 
1545 	assert(value < 1);
1546 	p->stripdata[pos] = value;
1547 }
1548 
1549 /*
1550  - enlarge - enlarge the strip
1551  == static int enlarge(register struct parse *p, sopno size);
1552  */
1553 static int
1554 enlarge(register struct parse *p, register sopno size)
1555 {
1556 	register sop *sp;
1557 	register RCHAR_T *dp;
1558 	sopno osize;
1559 
1560 	if (p->ssize >= size)
1561 		return 1;
1562 
1563 	osize = p->ssize;
1564 	p->ssize = size;
1565 	if (MEMSIZE(p) > MEMLIMIT)
1566 		goto oomem;
1567 	sp = realloc(p->strip, p->ssize * sizeof(sop));
1568 	if (sp == NULL)
1569 		goto oomem;
1570 	p->strip = sp;
1571 	dp = realloc(p->stripdata, p->ssize * sizeof(RCHAR_T));
1572 	if (dp == NULL) {
1573 oomem:
1574 		p->ssize = osize;
1575 		SETERROR(REG_ESPACE);
1576 		return 0;
1577 	}
1578 	p->stripdata = dp;
1579 	return 1;
1580 }
1581 
1582 /*
1583  - stripsnug - compact the strip
1584  == static void stripsnug(register struct parse *p, register struct re_guts *g);
1585  */
1586 static void
1587 stripsnug(register struct parse *p, register struct re_guts *g)
1588 {
1589 	g->nstates = p->slen;
1590 	g->strip = (sop *)realloc((char *)p->strip,
1591 	    p->slen * sizeof(sop));
1592 	if (g->strip == NULL) {
1593 		SETERROR(REG_ESPACE);
1594 		g->strip = p->strip;
1595 	}
1596 	g->stripdata = (RCHAR_T *)realloc((char *)p->stripdata,
1597 	    p->slen * sizeof(RCHAR_T));
1598 	if (g->stripdata == NULL) {
1599 		SETERROR(REG_ESPACE);
1600 		g->stripdata = p->stripdata;
1601 	}
1602 }
1603 
1604 /*
1605  - findmust - fill in must and mlen with longest mandatory literal string
1606  == static void findmust(register struct parse *p, register struct re_guts *g);
1607  *
1608  * This algorithm could do fancy things like analyzing the operands of |
1609  * for common subsequences.  Someday.  This code is simple and finds most
1610  * of the interesting cases.
1611  *
1612  * Note that must and mlen got initialized during setup.
1613  */
1614 static void
1615 findmust(struct parse *p, register struct re_guts *g)
1616 {
1617 	register sop *scans;
1618 	register RCHAR_T *scand;
1619 	sop *starts = 0;
1620 	RCHAR_T *startd = NULL;
1621 	register sop *newstarts = 0;
1622 	register RCHAR_T *newstartd = NULL;
1623 	register sopno newlen;
1624 	register sop s;
1625 	register RCHAR_T d;
1626 	register RCHAR_T *cp;
1627 	register sopno i;
1628 
1629 	/* avoid making error situations worse */
1630 	if (p->error != 0)
1631 		return;
1632 
1633 	/* find the longest OCHAR sequence in strip */
1634 	newlen = 0;
1635 	scans = g->strip + 1;
1636 	scand = g->stripdata + 1;
1637 	do {
1638 		s = *scans++;
1639 		d = *scand++;
1640 		switch (s) {
1641 		case OCHAR:		/* sequence member */
1642 			if (newlen == 0) {		/* new sequence */
1643 				newstarts = scans - 1;
1644 				newstartd = scand - 1;
1645 			}
1646 			newlen++;
1647 			break;
1648 		case OPLUS_:		/* things that don't break one */
1649 		case OLPAREN:
1650 		case ORPAREN:
1651 			break;
1652 		case OQUEST_:		/* things that must be skipped */
1653 		case OCH_:
1654 			scans--;
1655 			scand--;
1656 			do {
1657 				scans += d;
1658 				scand += d;
1659 				s = *scans;
1660 				d = *scand;
1661 				/* assert() interferes w debug printouts */
1662 				if (s != O_QUEST && s != O_CH && s != OOR2) {
1663 					g->iflags |= BAD;
1664 					return;
1665 				}
1666 			} while (s != O_QUEST && s != O_CH);
1667 			/* fallthrough */
1668 		default:		/* things that break a sequence */
1669 			if (newlen > g->mlen) {		/* ends one */
1670 				starts = newstarts;
1671 				startd = newstartd;
1672 				g->mlen = newlen;
1673 			}
1674 			newlen = 0;
1675 			break;
1676 		}
1677 	} while (s != OEND);
1678 
1679 	if (g->mlen == 0)		/* there isn't one */
1680 		return;
1681 
1682 	/* turn it into a character string */
1683 	g->must = malloc(((size_t)g->mlen + 1) * sizeof(RCHAR_T));
1684 	if (g->must == NULL) {		/* argh; just forget it */
1685 		g->mlen = 0;
1686 		return;
1687 	}
1688 	cp = g->must;
1689 	scans = starts;
1690 	scand = startd;
1691 	for (i = g->mlen; i > 0; i--) {
1692 		for (;;) {
1693 			s = *scans++;
1694 			d = *scand++;
1695 			if (s == OCHAR)
1696 				break;
1697 		}
1698 		assert(cp < g->must + g->mlen);
1699 		*cp++ = d;
1700 	}
1701 	assert(cp == g->must + g->mlen);
1702 	*cp++ = '\0';		/* just on general principles */
1703 }
1704 
1705 /*
1706  - pluscount - count + nesting
1707  == static sopno pluscount(register struct parse *p, register struct re_guts *g);
1708  */
1709 static sopno			/* nesting depth */
1710 pluscount(struct parse *p, register struct re_guts *g)
1711 {
1712 	register sop *scan;
1713 	register sop s;
1714 	register sopno plusnest = 0;
1715 	register sopno maxnest = 0;
1716 
1717 	if (p->error != 0)
1718 		return(0);	/* there may not be an OEND */
1719 
1720 	scan = g->strip + 1;
1721 	do {
1722 		s = *scan++;
1723 		switch (s) {
1724 		case OPLUS_:
1725 			plusnest++;
1726 			break;
1727 		case O_PLUS:
1728 			if (plusnest > maxnest)
1729 				maxnest = plusnest;
1730 			plusnest--;
1731 			break;
1732 		}
1733 	} while (s != OEND);
1734 	if (plusnest != 0)
1735 		g->iflags |= BAD;
1736 	return(maxnest);
1737 }
1738