/*-
 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
 * Copyright (c) 1992, 1993, 1994
 *		The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Henry Spencer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *		This product includes software developed by the University of
 *		California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *		@(#)regcomp.c	8.5 (Berkeley) 3/20/94
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)regcomp.c	8.5 (Berkeley) 3/20/94";

#endif	 /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <assert.h>

#include "regex/regex.h"
#include "regex/utils.h"
#include "regex/regex2.h"
#include "regex/cclass.h"
#include "regex/cname.h"

/*
 * parse structure, passed up and down to avoid global variables and
 * other clumsinesses
 */
struct parse
{
	pg_wchar   *next;			/* next character in RE */
	pg_wchar   *end;			/* end of string (-> NUL normally) */
	int			error;			/* has an error been seen? */
	sop		   *strip;			/* malloced strip */
	sopno		ssize;			/* malloced strip size (allocated) */
	sopno		slen;			/* malloced strip length (used) */
	int			ncsalloc;		/* number of csets allocated */
	struct re_guts *g;
#define  NPAREN  10				/* we need to remember () 1-9 for back
								 * refs */
	sopno		pbegin[NPAREN]; /* -> ( ([0] unused) */
	sopno		pend[NPAREN];	/* -> ) ([0] unused) */
};

/* ========= begin header generated by ./mkh ========= */
#ifdef __cplusplus
extern		"C"
{
#endif

/* === regcomp.c === */
	static void p_ere(struct parse * p, int stop);
	static void p_ere_exp(struct parse * p);
	static void p_str(struct parse * p);
	static void p_bre(struct parse * p, int end1, int end2);
	static int	p_simp_re(struct parse * p, int starordinary);
	static int	p_count(struct parse * p);
	static void p_bracket(struct parse * p);
	static void p_b_term(struct parse * p, cset *cs);
	static void p_b_cclass(struct parse * p, cset *cs);
	static void p_b_eclass(struct parse * p, cset *cs);
	static pg_wchar p_b_symbol(struct parse * p);
	static char p_b_coll_elem(struct parse * p, int endc);
#ifdef MULTIBYTE
	static unsigned char othercase(int ch);
#else
	static char othercase(int ch);
#endif
	static void bothcases(struct parse * p, int ch);
	static void ordinary(struct parse * p, int ch);
	static void nonnewline(struct parse * p);
	static void repeat(struct parse * p, sopno start, int from, int to);
	static int	seterr(struct parse * p, int e);
	static cset *allocset(struct parse * p);
	static void freeset(struct parse * p, cset *cs);
	static int	freezeset(struct parse * p, cset *cs);
	static int	firstch(struct parse * p, cset *cs);
	static int	nch(struct parse * p, cset *cs);
	static void mcadd(struct parse * p, cset *cs, char *cp);
	static void mcinvert(struct parse * p, cset *cs);
	static void mccase(struct parse * p, cset *cs);
	static int	isinsets(struct re_guts * g, int c);
	static int	samesets(struct re_guts * g, int c1, int c2);
	static void categorize(struct parse * p, struct re_guts * g);
	static sopno dupl(struct parse * p, sopno start, sopno finish);
	static void doemit(struct parse * p, sop op, size_t opnd);
	static void doinsert(struct parse * p, sop op, size_t opnd, sopno pos);
	static void dofwd(struct parse * p, sopno pos, sop value);
	static void enlarge(struct parse * p, sopno size);
	static void stripsnug(struct parse * p, struct re_guts * g);
	static void findmust(struct parse * p, struct re_guts * g);
	static sopno pluscount(struct parse * p, struct re_guts * g);
	static int	pg_isdigit(int c);
	static int	pg_isalpha(int c);
	static int	pg_isupper(int c);
	static int	pg_islower(int c);

#ifdef __cplusplus
}

#endif
/* ========= end header generated by ./mkh ========= */

static pg_wchar nuls[10];		/* place to point scanner in event of
								 * error */

/*
 * macros for use with parse structure
 * BEWARE:	these know that the parse structure is named `p' !!!
 */
#define PEEK()	(*p->next)
#define PEEK2() (*(p->next+1))
#define MORE()	(p->next < p->end)
#define MORE2() (p->next+1 < p->end)
#define SEE(c)	(MORE() && PEEK() == (c))
#define SEETWO(a, b)	(MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
#define EAT(c)	((SEE(c)) ? (NEXT(), 1) : 0)
#define EATTWO(a, b)	((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
#define NEXT()	(p->next++)
#define NEXT2() (p->next += 2)
#define NEXTn(n)		(p->next += (n))
#define GETNEXT()		(*p->next++)
#define SETERROR(e)		seterr(p, (e))
#define REQUIRE(co, e)	if (!(co)) SETERROR(e)
#define MUSTSEE(c, e)	REQUIRE(MORE() && PEEK() == (c), e)
#define MUSTEAT(c, e)	REQUIRE(MORE() && GETNEXT() == (c), e)
#define MUSTNOTSEE(c, e)		REQUIRE(!MORE() || PEEK() != (c), e)
#define EMIT(op, sopnd) doemit(p, (sop)(op), (size_t)(sopnd))
#define INSERT(op, pos) doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
#define AHEAD(pos)				dofwd(p, pos, HERE()-(pos))
#define ASTERN(sop, pos)		EMIT(sop, HERE()-pos)
#define HERE()			(p->slen)
#define THERE()			(p->slen - 1)
#define THERETHERE()	(p->slen - 2)
#define DROP(n) (p->slen -= (n))

#ifndef NDEBUG
static int	never = 0;			/* for use in asserts; shuts lint up */

#else
#define never	0				/* some <assert.h>s have bugs too */
#endif

/*
 - regcomp - interface for parser and compilation
 = extern int regcomp(regex_t *, const char *, int);
 = #define		REG_BASIC		0000
 = #define		REG_EXTENDED	0001
 = #define		REG_ICASE		0002
 = #define		REG_NOSUB		0004
 = #define		REG_NEWLINE		0010
 = #define		REG_NOSPEC		0020
 = #define		REG_PEND		0040
 = #define		REG_DUMP		0200
 */
int								/* 0 success, otherwise REG_something */
pg95_regcomp(preg, pattern, cflags)
regex_t    *preg;
const char *pattern;
int			cflags;
{
	struct parse pa;
	struct re_guts *g;
	struct parse *p = &pa;
	int			i;
	size_t		len;

#ifdef MULTIBYTE
	pg_wchar   *wcp;

#endif

#ifdef REDEBUG
#define  GOODFLAGS(f)	 (f)
#else
#define  GOODFLAGS(f)	 ((f)&~REG_DUMP)
#endif

	cflags = GOODFLAGS(cflags);
	if ((cflags & REG_EXTENDED) && (cflags & REG_NOSPEC))
		return REG_INVARG;

	if (cflags & REG_PEND)
	{
#ifdef MULTIBYTE
		wcp = preg->patsave;
		if (preg->re_endp < wcp)
			return REG_INVARG;
		len = preg->re_endp - wcp;
#else
		if (preg->re_endp < pattern)
			return REG_INVARG;
		len = preg->re_endp - pattern;
#endif
	}
	else
	{
#ifdef MULTIBYTE
		wcp = (pg_wchar *) malloc((strlen(pattern) + 1) * sizeof(pg_wchar));
		if (wcp == NULL)
			return REG_ESPACE;
		preg->patsave = wcp;
		(void) pg_mb2wchar((unsigned char *) pattern, wcp);
		len = pg_wchar_strlen(wcp);
#else

		len = strlen((char *) pattern);
#endif
	}

	/* do the mallocs early so failure handling is easy */
	g = (struct re_guts *) malloc(sizeof(struct re_guts) +
								  (NC - 1) * sizeof(cat_t));
	if (g == NULL)
		return REG_ESPACE;
	p->ssize = len / (size_t) 2 *(size_t) 3 + (size_t) 1;		/* ugh */

	p->strip = (sop *) malloc(p->ssize * sizeof(sop));
	p->slen = 0;
	if (p->strip == NULL)
	{
		free((char *) g);
		return REG_ESPACE;
	}

	/* set things up */
	p->g = g;
#ifdef MULTIBYTE
	p->next = wcp;
#else
	p->next = (pg_wchar *) pattern;		/* convenience; we do not modify
										 * it */
#endif
	p->end = p->next + len;
	p->error = 0;
	p->ncsalloc = 0;
	for (i = 0; i < NPAREN; i++)
	{
		p->pbegin[i] = 0;
		p->pend[i] = 0;
	}
	g->csetsize = NC;
	g->sets = NULL;
	g->setbits = NULL;
	g->ncsets = 0;
	g->cflags = cflags;
	g->iflags = 0;
	g->nbol = 0;
	g->neol = 0;
	g->must = NULL;
	g->mlen = 0;
	g->nsub = 0;
	g->ncategories = 1;			/* category 0 is "everything else" */
	g->categories = &g->catspace[-(CHAR_MIN)];
	memset((char *) g->catspace, 0, NC * sizeof(cat_t));
	g->backrefs = 0;

	/* do it */
	EMIT(OEND, 0);
	g->firststate = THERE();
	if (cflags & REG_EXTENDED)
		p_ere(p, OUT);
	else if (cflags & REG_NOSPEC)
		p_str(p);
	else
		p_bre(p, OUT, OUT);
	EMIT(OEND, 0);
	g->laststate = THERE();

	/* tidy up loose ends and fill things in */
	categorize(p, g);
	stripsnug(p, g);
	findmust(p, g);
	g->nplus = pluscount(p, g);
	g->magic = MAGIC2;
	preg->re_nsub = g->nsub;
	preg->re_g = g;
	preg->re_magic = MAGIC1;
#ifndef REDEBUG
	/* not debugging, so can't rely on the assert() in regexec() */
	if (g->iflags & BAD)
		SETERROR(REG_ASSERT);
#endif

	/* win or lose, we're done */
	if (p->error != 0)			/* lose */
		pg95_regfree(preg);
	return p->error;
}

/*
 - p_ere - ERE parser top level, concatenation and alternation
 == static void p_ere(struct parse *p, int stop);
 */
static void
p_ere(p, stop)
struct parse *p;
int			stop;				/* character this ERE should end at */
{
	char		c;
	sopno		prevback = 0;
	sopno		prevfwd = 0;
	sopno		conc;
	int			first = 1;		/* is this the first alternative? */

	for (;;)
	{
		/* do a bunch of concatenated expressions */
		conc = HERE();
		while (MORE() && (c = PEEK()) != '|' && c != stop)
			p_ere_exp(p);
		REQUIRE(HERE() != conc, REG_EMPTY);		/* require nonempty */

		if (!EAT('|'))
			break;				/* NOTE BREAK OUT */

		if (first)
		{
			INSERT(OCH_, conc); /* offset is wrong */
			prevfwd = conc;
			prevback = conc;
			first = 0;
		}
		ASTERN(OOR1, prevback);
		prevback = THERE();
		AHEAD(prevfwd);			/* fix previous offset */
		prevfwd = HERE();
		EMIT(OOR2, 0);			/* offset is very wrong */
	}

	if (!first)
	{							/* tail-end fixups */
		AHEAD(prevfwd);
		ASTERN(O_CH, prevback);
	}

	assert(!MORE() || SEE(stop));
}

/*
 - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
 == static void p_ere_exp(struct parse *p);
 */
static void
p_ere_exp(p)
struct parse *p;
{
	pg_wchar	c;
	sopno		pos;
	int			count;
	int			count2;
	sopno		subno;
	int			wascaret = 0;

	assert(MORE());				/* caller should have ensured this */
	c = GETNEXT();

	pos = HERE();
	switch (c)
	{
		case '(':
			REQUIRE(MORE(), REG_EPAREN);
			p->g->nsub++;
			subno = p->g->nsub;
			if (subno < NPAREN)
				p->pbegin[subno] = HERE();
			EMIT(OLPAREN, subno);
			if (!SEE(')'))
				p_ere(p, ')');
			if (subno < NPAREN)
			{
				p->pend[subno] = HERE();
				assert(p->pend[subno] != 0);
			}
			EMIT(ORPAREN, subno);
			MUSTEAT(')', REG_EPAREN);
			break;
#ifndef POSIX_MISTAKE
		case ')':				/* happens only if no current unmatched ( */

			/*
			 * You may ask, why the ifndef?  Because I didn't notice this
			 * until slightly too late for 1003.2, and none of the other
			 * 1003.2 regular-expression reviewers noticed it at all.  So
			 * an unmatched ) is legal POSIX, at least until we can get it
			 * fixed.
			 */
			SETERROR(REG_EPAREN);
			break;
#endif
		case '^':
			EMIT(OBOL, 0);
			p->g->iflags |= USEBOL;
			p->g->nbol++;
			wascaret = 1;
			break;
		case '$':
			EMIT(OEOL, 0);
			p->g->iflags |= USEEOL;
			p->g->neol++;
			break;
		case '|':
			SETERROR(REG_EMPTY);
			break;
		case '*':
		case '+':
		case '?':
			SETERROR(REG_BADRPT);
			break;
		case '.':
			if (p->g->cflags & REG_NEWLINE)
				nonnewline(p);
			else
				EMIT(OANY, 0);
			break;
		case '[':
			p_bracket(p);
			break;
		case '\\':
			REQUIRE(MORE(), REG_EESCAPE);
			c = GETNEXT();
			ordinary(p, c);
			break;
		case '{':				/* okay as ordinary except if digit
								 * follows */
			REQUIRE(!MORE() || !pg_isdigit(PEEK()), REG_BADRPT);
			/* FALLTHROUGH */
		default:
			ordinary(p, c);
			break;
	}

	if (!MORE())
		return;
	c = PEEK();
	/* we call { a repetition if followed by a digit */
	if (!(c == '*' || c == '+' || c == '?' ||
		  (c == '{' && MORE2() && pg_isdigit(PEEK2()))))
		return;					/* no repetition, we're done */
	NEXT();

	REQUIRE(!wascaret, REG_BADRPT);
	switch (c)
	{
		case '*':				/* implemented as +? */
			/* this case does not require the (y|) trick, noKLUDGE */
			INSERT(OPLUS_, pos);
			ASTERN(O_PLUS, pos);
			INSERT(OQUEST_, pos);
			ASTERN(O_QUEST, pos);
			break;
		case '+':
			INSERT(OPLUS_, pos);
			ASTERN(O_PLUS, pos);
			break;
		case '?':
			/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
			INSERT(OCH_, pos);	/* offset slightly wrong */
			ASTERN(OOR1, pos);	/* this one's right */
			AHEAD(pos);			/* fix the OCH_ */
			EMIT(OOR2, 0);		/* offset very wrong... */
			AHEAD(THERE());		/* ...so fix it */
			ASTERN(O_CH, THERETHERE());
			break;
		case '{':
			count = p_count(p);
			if (EAT(','))
			{
				if (pg_isdigit(PEEK()))
				{
					count2 = p_count(p);
					REQUIRE(count <= count2, REG_BADBR);
				}
				else
/* single number with comma */
					count2 = INFINITY;
			}
			else
/* just a single number */
				count2 = count;
			repeat(p, pos, count, count2);
			if (!EAT('}'))
			{					/* error heuristics */
				while (MORE() && PEEK() != '}')
					NEXT();
				REQUIRE(MORE(), REG_EBRACE);
				SETERROR(REG_BADBR);
			}
			break;
	}

	if (!MORE())
		return;
	c = PEEK();
	if (!(c == '*' || c == '+' || c == '?' ||
		  (c == '{' && MORE2() && pg_isdigit(PEEK2()))))
		return;
	SETERROR(REG_BADRPT);
}

/*
 - p_str - string (no metacharacters) "parser"
 == static void p_str(struct parse *p);
 */
static void
p_str(p)
struct parse *p;
{
	REQUIRE(MORE(), REG_EMPTY);
	while (MORE())
		ordinary(p, GETNEXT());
}

/*
 - p_bre - BRE parser top level, anchoring and concatenation
 == static void p_bre(struct parse *p, int end1, \
 ==		int end2);
 * Giving end1 as OUT essentially eliminates the end1/end2 check.
 *
 * This implementation is a bit of a kludge, in that a trailing $ is first
 * taken as an ordinary character and then revised to be an anchor.  The
 * only undesirable side effect is that '$' gets included as a character
 * category in such cases.	This is fairly harmless; not worth fixing.
 * The amount of lookahead needed to avoid this kludge is excessive.
 */
static void
p_bre(p, end1, end2)
struct parse *p;
int			end1;				/* first terminating character */
int			end2;				/* second terminating character */
{
	sopno		start = HERE();
	int			first = 1;		/* first subexpression? */
	int			wasdollar = 0;

	if (EAT('^'))
	{
		EMIT(OBOL, 0);
		p->g->iflags |= USEBOL;
		p->g->nbol++;
	}
	while (MORE() && !SEETWO(end1, end2))
	{
		wasdollar = p_simp_re(p, first);
		first = 0;
	}
	if (wasdollar)
	{							/* oops, that was a trailing anchor */
		DROP(1);
		EMIT(OEOL, 0);
		p->g->iflags |= USEEOL;
		p->g->neol++;
	}

	REQUIRE(HERE() != start, REG_EMPTY);		/* require nonempty */
}

/*
 - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
 == static int p_simp_re(struct parse *p, int starordinary);
 */
static int						/* was the simple RE an unbackslashed $? */
p_simp_re(p, starordinary)
struct parse *p;
int			starordinary;		/* is a leading * an ordinary character? */
{
	int			c;
	int			count;
	int			count2;
	sopno		pos;
	int			i;
	sopno		subno;

#define  BACKSL  (1<<24)

	pos = HERE();				/* repetion op, if any, covers from here */

	assert(MORE());				/* caller should have ensured this */
	c = GETNEXT();
	if (c == '\\')
	{
		REQUIRE(MORE(), REG_EESCAPE);
#ifdef MULTIBYTE
		c = BACKSL | (pg_wchar) GETNEXT();
#else
		c = BACKSL | (unsigned char) GETNEXT();
#endif
	}
	switch (c)
	{
		case '.':
			if (p->g->cflags & REG_NEWLINE)
				nonnewline(p);
			else
				EMIT(OANY, 0);
			break;
		case '[':
			p_bracket(p);
			break;
		case BACKSL | '{':
			SETERROR(REG_BADRPT);
			break;
		case BACKSL | '(':
			p->g->nsub++;
			subno = p->g->nsub;
			if (subno < NPAREN)
				p->pbegin[subno] = HERE();
			EMIT(OLPAREN, subno);
			/* the MORE here is an error heuristic */
			if (MORE() && !SEETWO('\\', ')'))
				p_bre(p, '\\', ')');
			if (subno < NPAREN)
			{
				p->pend[subno] = HERE();
				assert(p->pend[subno] != 0);
			}
			EMIT(ORPAREN, subno);
			REQUIRE(EATTWO('\\', ')'), REG_EPAREN);
			break;
		case BACKSL | ')':		/* should not get here -- must be user */
		case BACKSL | '}':
			SETERROR(REG_EPAREN);
			break;
		case BACKSL | '1':
		case BACKSL | '2':
		case BACKSL | '3':
		case BACKSL | '4':
		case BACKSL | '5':
		case BACKSL | '6':
		case BACKSL | '7':
		case BACKSL | '8':
		case BACKSL | '9':
			i = (c & ~BACKSL) - '0';
			assert(i < NPAREN);
			if (p->pend[i] != 0)
			{
				assert(i <= p->g->nsub);
				EMIT(OBACK_, i);
				assert(p->pbegin[i] != 0);
				assert(OP(p->strip[p->pbegin[i]]) == OLPAREN);
				assert(OP(p->strip[p->pend[i]]) == ORPAREN);
				dupl(p, p->pbegin[i] + 1, p->pend[i]);
				EMIT(O_BACK, i);
			}
			else
				SETERROR(REG_ESUBREG);
			p->g->backrefs = 1;
			break;
		case '*':
			REQUIRE(starordinary, REG_BADRPT);
			/* FALLTHROUGH */
		default:
			ordinary(p, c & ~BACKSL);
			break;
	}

	if (EAT('*'))
	{							/* implemented as +? */
		/* this case does not require the (y|) trick, noKLUDGE */
		INSERT(OPLUS_, pos);
		ASTERN(O_PLUS, pos);
		INSERT(OQUEST_, pos);
		ASTERN(O_QUEST, pos);
	}
	else if (EATTWO('\\', '{'))
	{
		count = p_count(p);
		if (EAT(','))
		{
			if (MORE() && pg_isdigit(PEEK()))
			{
				count2 = p_count(p);
				REQUIRE(count <= count2, REG_BADBR);
			}
			else
/* single number with comma */
				count2 = INFINITY;
		}
		else
/* just a single number */
			count2 = count;
		repeat(p, pos, count, count2);
		if (!EATTWO('\\', '}'))
		{						/* error heuristics */
			while (MORE() && !SEETWO('\\', '}'))
				NEXT();
			REQUIRE(MORE(), REG_EBRACE);
			SETERROR(REG_BADBR);
		}
	}
	else if (c == (unsigned char) '$')	/* $ (but not \$) ends it */
		return 1;

	return 0;
}

/*
 - p_count - parse a repetition count
 == static int p_count(struct parse *p);
 */
static int						/* the value */
p_count(p)
struct parse *p;
{
	int			count = 0;
	int			ndigits = 0;

	while (MORE() && pg_isdigit(PEEK()) && count <= DUPMAX)
	{
		count = count * 10 + (GETNEXT() - '0');
		ndigits++;
	}

	REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
	return count;
}

/*
 - p_bracket - parse a bracketed character list
 == static void p_bracket(struct parse *p);
 *
 * Note a significant property of this code:  if the allocset() did SETERROR,
 * no set operations are done.
 */
static void
p_bracket(p)
struct parse *p;
{
	cset	   *cs = allocset(p);
	int			invert = 0;

#ifdef MULTIBYTE
	pg_wchar	sp1[] = {'[', ':', '<', ':', ']', ']'};
	pg_wchar	sp2[] = {'[', ':', '>', ':', ']', ']'};

#endif

	/* Dept of Truly Sickening Special-Case Kludges */
#ifdef MULTIBYTE
	if (p->next + 5 < p->end && pg_wchar_strncmp(p->next, sp1, 6) == 0)
#else
	if (p->next + 5 < p->end && strncmp(p->next, "[:<:]]", 6) == 0)
#endif
	{
		EMIT(OBOW, 0);
		NEXTn(6);
		return;
	}
#ifdef MULTIBYTE
	if (p->next + 5 < p->end && pg_wchar_strncmp(p->next, sp2, 6) == 0)
#else
	if (p->next + 5 < p->end && strncmp(p->next, "[:>:]]", 6) == 0)
#endif
	{
		EMIT(OEOW, 0);
		NEXTn(6);
		return;
	}

	if (EAT('^'))
		invert++;				/* make note to invert set at end */
	if (EAT(']'))
		CHadd(cs, ']');
	else if (EAT('-'))
		CHadd(cs, '-');
	while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
		p_b_term(p, cs);
	if (EAT('-'))
		CHadd(cs, '-');
	MUSTEAT(']', REG_EBRACK);

	if (p->error != 0)			/* don't mess things up further */
		return;

	if (p->g->cflags & REG_ICASE)
	{
		int			i;
		int			ci;

		for (i = p->g->csetsize - 1; i >= 0; i--)
			if (CHIN(cs, i) && pg_isalpha(i))
			{
				ci = othercase(i);
				if (ci != i)
					CHadd(cs, ci);
			}
		if (cs->multis != NULL)
			mccase(p, cs);
	}
	if (invert)
	{
		int			i;

		for (i = p->g->csetsize - 1; i >= 0; i--)
			if (CHIN(cs, i))
				CHsub(cs, i);
			else
				CHadd(cs, i);
		if (p->g->cflags & REG_NEWLINE)
			CHsub(cs, '\n');
		if (cs->multis != NULL)
			mcinvert(p, cs);
	}

	assert(cs->multis == NULL); /* xxx */

	if (nch(p, cs) == 1)
	{							/* optimize singleton sets */
		ordinary(p, firstch(p, cs));
		freeset(p, cs);
	}
	else
		EMIT(OANYOF, freezeset(p, cs));
}

/*
 - p_b_term - parse one term of a bracketed character list
 == static void p_b_term(struct parse *p, cset *cs);
 */
static void
p_b_term(p, cs)
struct parse *p;
cset	   *cs;
{
	pg_wchar	c;
	pg_wchar	start,
				finish;
	int			i;

	/* classify what we've got */
	switch ((MORE()) ? PEEK() : '\0')
	{
		case '[':
			c = (MORE2()) ? PEEK2() : '\0';
			break;
		case '-':
			SETERROR(REG_ERANGE);
			return;				/* NOTE RETURN */
			break;
		default:
			c = '\0';
			break;
	}

	switch (c)
	{
		case ':':				/* character class */
			NEXT2();
			REQUIRE(MORE(), REG_EBRACK);
			c = PEEK();
			REQUIRE(c != '-' && c != ']', REG_ECTYPE);
			p_b_cclass(p, cs);
			REQUIRE(MORE(), REG_EBRACK);
			REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
			break;
		case '=':				/* equivalence class */
			NEXT2();
			REQUIRE(MORE(), REG_EBRACK);
			c = PEEK();
			REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
			p_b_eclass(p, cs);
			REQUIRE(MORE(), REG_EBRACK);
			REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
			break;
		default:				/* symbol, ordinary character, or range */
/* xxx revision needed for multichar stuff */
			start = p_b_symbol(p);
			if (SEE('-') && MORE2() && PEEK2() != ']')
			{
				/* range */
				NEXT();
				if (EAT('-'))
					finish = '-';
				else
					finish = p_b_symbol(p);
			}
			else
				finish = start;
/* xxx what about signed chars here... */
			REQUIRE(start <= finish, REG_ERANGE);
#ifdef MULTIBYTE
			if (CHlc(start) != CHlc(finish))
				SETERROR(REG_ERANGE);
#endif
			for (i = start; i <= finish; i++)
				CHadd(cs, i);
			break;
	}
}

/*
 - p_b_cclass - parse a character-class name and deal with it
 == static void p_b_cclass(struct parse *p, cset *cs);
 */
static void
p_b_cclass(p, cs)
struct parse *p;
cset	   *cs;
{
	pg_wchar   *sp = p->next;
	struct cclass *cp;
	size_t		len;
	char	   *u;
	char		c;

	while (MORE() && pg_isalpha(PEEK()))
		NEXT();
	len = p->next - sp;
	for (cp = cclasses; cp->name != NULL; cp++)
#ifdef MULTIBYTE
		if (pg_char_and_wchar_strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
#else
		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
#endif
			break;
	if (cp->name == NULL)
	{
		/* oops, didn't find it */
		SETERROR(REG_ECTYPE);
		return;
	}

	u = cp->chars;
	while ((c = *u++) != '\0')
		CHadd(cs, c);
	for (u = cp->multis; *u != '\0'; u += strlen(u) + 1)
		MCadd(p, cs, u);
}

/*
 - p_b_eclass - parse an equivalence-class name and deal with it
 == static void p_b_eclass(struct parse *p, cset *cs);
 *
 * This implementation is incomplete. xxx
 */
static void
p_b_eclass(p, cs)
struct parse *p;
cset	   *cs;
{
	char		c;

	c = p_b_coll_elem(p, '=');
	CHadd(cs, c);
}

/*
 - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
 == static char p_b_symbol(struct parse *p);
 */
static pg_wchar			/* value of symbol */
p_b_symbol(p)
struct parse *p;
{
	pg_wchar	value;

	REQUIRE(MORE(), REG_EBRACK);
	if (!EATTWO('[', '.'))
		return GETNEXT();

	/* collating symbol */
	value = p_b_coll_elem(p, '.');
	REQUIRE(EATTWO('.', ']'), REG_ECOLLATE);
	return value;
}

/*
 - p_b_coll_elem - parse a collating-element name and look it up
 == static char p_b_coll_elem(struct parse *p, int endc);
 */
static char						/* value of collating element */
p_b_coll_elem(p, endc)
struct parse *p;
int			endc;				/* name ended by endc,']' */
{
	pg_wchar   *sp = p->next;
	struct cname *cp;
	int			len;

	while (MORE() && !SEETWO(endc, ']'))
		NEXT();
	if (!MORE())
	{
		SETERROR(REG_EBRACK);
		return 0;
	}
	len = p->next - sp;
	for (cp = cnames; cp->name != NULL; cp++)
#ifdef MULTIBYTE
		if (pg_char_and_wchar_strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
#else
		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
#endif
			return cp->code;	/* known name */
	if (len == 1)
		return *sp;				/* single character */
	SETERROR(REG_ECOLLATE);		/* neither */
	return 0;
}

/*
 - othercase - return the case counterpart of an alphabetic
 == static char othercase(int ch);
 */
#ifdef MULTIBYTE
static unsigned char			/* if no counterpart, return ch */
#else
static char						/* if no counterpart, return ch */
#endif
othercase(ch)
int			ch;
{
	assert(pg_isalpha(ch));
	if (pg_isupper(ch))
#ifdef MULTIBYTE
		return (unsigned char) tolower(ch);
#else
		return tolower(ch);
#endif
	else if (pg_islower(ch))
#ifdef MULTIBYTE
		return (unsigned char) toupper(ch);
#else
		return toupper(ch);
#endif
	else
/* peculiar, but could happen */
#ifdef MULTIBYTE
		return (unsigned char) ch;
#else
		return ch;
#endif
}

/*
 - bothcases - emit a dualcase version of a two-case character
 == static void bothcases(struct parse *p, int ch);
 *
 * Boy, is this implementation ever a kludge...
 */
static void
bothcases(p, ch)
struct parse *p;
int			ch;
{
	pg_wchar   *oldnext = p->next;
	pg_wchar   *oldend = p->end;
	pg_wchar	bracket[3];

	assert(othercase(ch) != ch);/* p_bracket() would recurse */
	p->next = bracket;
	p->end = bracket + 2;
	bracket[0] = ch;
	bracket[1] = ']';
	bracket[2] = '\0';
	p_bracket(p);
	assert(p->next == bracket + 2);
	p->next = oldnext;
	p->end = oldend;
}

/*
 - ordinary - emit an ordinary character
 == static void ordinary(struct parse *p, int ch);
 */
static void
ordinary(p, ch)
struct parse *p;
int			ch;
{
	cat_t	   *cap = p->g->categories;

	if ((p->g->cflags & REG_ICASE) && pg_isalpha(ch) && othercase(ch) != ch)
		bothcases(p, ch);
	else
	{
#ifdef MULTIBYTE
		EMIT(OCHAR, (pg_wchar) ch);
#else
		EMIT(OCHAR, (unsigned char) ch);
#endif
		if (ch >= CHAR_MIN && ch <= CHAR_MAX && cap[ch] == 0)
			cap[ch] = p->g->ncategories++;
	}
}

/*
 - nonnewline - emit REG_NEWLINE version of OANY
 == static void nonnewline(struct parse *p);
 *
 * Boy, is this implementation ever a kludge...
 */
static void
nonnewline(p)
struct parse *p;
{
	pg_wchar   *oldnext = p->next;
	pg_wchar   *oldend = p->end;
	pg_wchar	bracket[4];

	p->next = bracket;
	p->end = bracket + 3;
	bracket[0] = '^';
	bracket[1] = '\n';
	bracket[2] = ']';
	bracket[3] = '\0';
	p_bracket(p);
	assert(p->next == bracket + 3);
	p->next = oldnext;
	p->end = oldend;
}

/*
 - repeat - generate code for a bounded repetition, recursively if needed
 == static void repeat(struct parse *p, sopno start, int from, int to);
 */
static void
repeat(p, start, from, to)
struct parse *p;
sopno		start;				/* operand from here to end of strip */
int			from;				/* repeated from this number */
int			to;					/* to this number of times (maybe
								 * INFINITY) */
{
	sopno		finish = HERE();

#define  N		 2
#define  INF	 3
#define  REP(f, t)		 ((f)*8 + (t))
#define  MAP(n)  (((n) <= 1) ? (n) : ((n) == INFINITY) ? INF : N)
	sopno		copy;

	if (p->error != 0)			/* head off possible runaway recursion */
		return;

	assert(from <= to);

	switch (REP(MAP(from), MAP(to)))
	{
		case REP(0, 0): /* must be user doing this */
			DROP(finish - start);		/* drop the operand */
			break;
		case REP(0, 1): /* as x{1,1}? */
		case REP(0, N): /* as x{1,n}? */
		case REP(0, INF):		/* as x{1,}? */
			/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
			INSERT(OCH_, start);/* offset is wrong... */
			repeat(p, start + 1, 1, to);
			ASTERN(OOR1, start);
			AHEAD(start);		/* ... fix it */
			EMIT(OOR2, 0);
			AHEAD(THERE());
			ASTERN(O_CH, THERETHERE());
			break;
		case REP(1, 1): /* trivial case */
			/* done */
			break;
		case REP(1, N): /* as x?x{1,n-1} */
			/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
			INSERT(OCH_, start);
			ASTERN(OOR1, start);
			AHEAD(start);
			EMIT(OOR2, 0);		/* offset very wrong... */
			AHEAD(THERE());		/* ...so fix it */
			ASTERN(O_CH, THERETHERE());
			copy = dupl(p, start + 1, finish + 1);
			assert(copy == finish + 4);
			repeat(p, copy, 1, to - 1);
			break;
		case REP(1, INF):		/* as x+ */
			INSERT(OPLUS_, start);
			ASTERN(O_PLUS, start);
			break;
		case REP(N, N): /* as xx{m-1,n-1} */
			copy = dupl(p, start, finish);
			repeat(p, copy, from - 1, to - 1);
			break;
		case REP(N, INF):		/* as xx{n-1,INF} */
			copy = dupl(p, start, finish);
			repeat(p, copy, from - 1, to);
			break;
		default:				/* "can't happen" */
			SETERROR(REG_ASSERT);		/* just in case */
			break;
	}
}

/*
 - seterr - set an error condition
 == static int seterr(struct parse *p, int e);
 */
static int						/* useless but makes type checking happy */
seterr(p, e)
struct parse *p;
int			e;
{
	if (p->error == 0)			/* keep earliest error condition */
		p->error = e;
	p->next = nuls;				/* try to bring things to a halt */
	p->end = nuls;
	return 0;					/* make the return value well-defined */
}

/*
 - allocset - allocate a set of characters for []
 == static cset *allocset(struct parse *p);
 */
static cset *
allocset(p)
struct parse *p;
{
	int			no = p->g->ncsets++;
	size_t		nc;
	size_t		nbytes;
	cset	   *cs;
	size_t		css = (size_t) p->g->csetsize;
	int			i;

	if (no >= p->ncsalloc)
	{							/* need another column of space */
		p->ncsalloc += CHAR_BIT;
		nc = p->ncsalloc;
		assert(nc % CHAR_BIT == 0);
		nbytes = nc / CHAR_BIT * css;
		if (p->g->sets == NULL)
			p->g->sets = (cset *) malloc(nc * sizeof(cset));
		else
			p->g->sets = (cset *) realloc((char *) p->g->sets,
										  nc * sizeof(cset));
		if (p->g->setbits == NULL)
			p->g->setbits = (uch *) malloc(nbytes);
		else
		{
			p->g->setbits = (uch *) realloc((char *) p->g->setbits,
											nbytes);
			/* xxx this isn't right if setbits is now NULL */
			for (i = 0; i < no; i++)
				p->g->sets[i].ptr = p->g->setbits + css * (i / CHAR_BIT);
		}
		if (p->g->sets != NULL && p->g->setbits != NULL)
			memset((char *) p->g->setbits + (nbytes - css),
				   0, css);
		else
		{
			no = 0;
			SETERROR(REG_ESPACE);
			/* caller's responsibility not to do set ops */
		}
	}

	assert(p->g->sets != NULL); /* xxx */
	cs = &p->g->sets[no];
	cs->ptr = p->g->setbits + css * ((no) / CHAR_BIT);
	cs->mask = 1 << ((no) % CHAR_BIT);
	cs->hash = 0;
	cs->smultis = 0;
	cs->multis = NULL;

	return cs;
}

/*
 - freeset - free a now-unused set
 == static void freeset(struct parse *p, cset *cs);
 */
static void
freeset(p, cs)
struct parse *p;
cset	   *cs;
{
	int			i;
	cset	   *top = &p->g->sets[p->g->ncsets];
	size_t		css = (size_t) p->g->csetsize;

	for (i = 0; i < css; i++)
		CHsub(cs, i);
	if (cs == top - 1)			/* recover only the easy case */
		p->g->ncsets--;
}

/*
 - freezeset - final processing on a set of characters
 == static int freezeset(struct parse *p, cset *cs);
 *
 * The main task here is merging identical sets.  This is usually a waste
 * of time (although the hash code minimizes the overhead), but can win
 * big if REG_ICASE is being used.	REG_ICASE, by the way, is why the hash
 * is done using addition rather than xor -- all ASCII [aA] sets xor to
 * the same value!
 */
static int						/* set number */
freezeset(p, cs)
struct parse *p;
cset	   *cs;
{
	uch			h = cs->hash;
	int			i;
	cset	   *top = &p->g->sets[p->g->ncsets];
	cset	   *cs2;
	size_t		css = (size_t) p->g->csetsize;

	/* look for an earlier one which is the same */
	for (cs2 = &p->g->sets[0]; cs2 < top; cs2++)
		if (cs2->hash == h && cs2 != cs)
		{
			/* maybe */
			for (i = 0; i < css; i++)
				if (!!CHIN(cs2, i) != !!CHIN(cs, i))
					break;		/* no */
			if (i == css)
				break;			/* yes */
		}

	if (cs2 < top)
	{							/* found one */
		freeset(p, cs);
		cs = cs2;
	}

	return (int) (cs - p->g->sets);
}

/*
 - firstch - return first character in a set (which must have at least one)
 == static int firstch(struct parse *p, cset *cs);
 */
static int						/* character; there is no "none" value */
firstch(p, cs)
struct parse *p;
cset	   *cs;
{
	int			i;
	size_t		css = (size_t) p->g->csetsize;

	for (i = 0; i < css; i++)
		if (CHIN(cs, i))
			return i;
	assert(never);
	return 0;					/* arbitrary */
}

/*
 - nch - number of characters in a set
 == static int nch(struct parse *p, cset *cs);
 */
static int
nch(p, cs)
struct parse *p;
cset	   *cs;
{
	int			i;
	size_t		css = (size_t) p->g->csetsize;
	int			n = 0;

	for (i = 0; i < css; i++)
		if (CHIN(cs, i))
			n++;
	return n;
}

/*
 - mcadd - add a collating element to a cset
 == static void mcadd(struct parse *p, cset *cs, \
 ==		char *cp);
 */
static void
mcadd(p, cs, cp)
struct parse *p;
cset	   *cs;
char	   *cp;
{
	size_t		oldend = cs->smultis;

	cs->smultis += strlen(cp) + 1;
	if (cs->multis == NULL)
		cs->multis = malloc(cs->smultis);
	else
		cs->multis = realloc(cs->multis, cs->smultis);
	if (cs->multis == NULL)
	{
		SETERROR(REG_ESPACE);
		return;
	}

	strcpy(cs->multis + oldend - 1, cp);
	cs->multis[cs->smultis - 1] = '\0';
}

/*
 - mcsub - subtract a collating element from a cset
 == static void mcsub(cset *cs, char *cp);
 */
/*
static void
mcsub(cs, cp)
cset *cs;
char *cp;
{
		char *fp = mcfind(cs, cp);
		size_t len = strlen(fp);

		assert(fp != NULL);
		memmove(fp, fp + len + 1,
								cs->smultis - (fp + len + 1 - cs->multis));
		cs->smultis -= len;

		if (cs->smultis == 0) {
				free(cs->multis);
				cs->multis = NULL;
				return;
		}

		cs->multis = realloc(cs->multis, cs->smultis);
		assert(cs->multis != NULL);
}
*/

/*
 - mcin - is a collating element in a cset?
 == static int mcin(cset *cs, char *cp);
 */
/*
static int
mcin(cs, cp)
cset *cs;
char *cp;
{
		return(mcfind(cs, cp) != NULL);
}
*/

/*
 - mcfind - find a collating element in a cset
 == static char *mcfind(cset *cs, char *cp);
 */
/*
static char *
mcfind(cs, cp)
cset *cs;
char *cp;
{
		char *p;

		if (cs->multis == NULL)
				return(NULL);
		for (p = cs->multis; *p != '\0'; p += strlen(p) + 1)
				if (strcmp(cp, p) == 0)
						return(p);
		return(NULL);
}
*/
/*
 - mcinvert - invert the list of collating elements in a cset
 == static void mcinvert(struct parse *p, cset *cs);
 *
 * This would have to know the set of possibilities.  Implementation
 * is deferred.
 */
static void
mcinvert(p, cs)
struct parse *p;
cset	   *cs;
{
	assert(cs->multis == NULL); /* xxx */
}

/*
 - mccase - add case counterparts of the list of collating elements in a cset
 == static void mccase(struct parse *p, cset *cs);
 *
 * This would have to know the set of possibilities.  Implementation
 * is deferred.
 */
static void
mccase(p, cs)
struct parse *p;
cset	   *cs;
{
	assert(cs->multis == NULL); /* xxx */
}

/*
 - isinsets - is this character in any sets?
 == static int isinsets(struct re_guts *g, int c);
 */
static int						/* predicate */
isinsets(g, c)
struct re_guts *g;
int			c;
{
	uch		   *col;
	int			i;
	int			ncols = (g->ncsets + (CHAR_BIT - 1)) / CHAR_BIT;
	unsigned	uc = (unsigned char) c;

	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
		if (col[uc] != 0)
			return 1;
	return 0;
}

/*
 - samesets - are these two characters in exactly the same sets?
 == static int samesets(struct re_guts *g, int c1, int c2);
 */
static int						/* predicate */
samesets(g, c1, c2)
struct re_guts *g;
int			c1;
int			c2;
{
	uch		   *col;
	int			i;
	int			ncols = (g->ncsets + (CHAR_BIT - 1)) / CHAR_BIT;
	unsigned	uc1 = (unsigned char) c1;
	unsigned	uc2 = (unsigned char) c2;

	for (i = 0, col = g->setbits; i < ncols; i++, col += g->csetsize)
		if (col[uc1] != col[uc2])
			return 0;
	return 1;
}

/*
 - categorize - sort out character categories
 == static void categorize(struct parse *p, struct re_guts *g);
 */
static void
categorize(p, g)
struct parse *p;
struct re_guts *g;
{
	cat_t	   *cats = g->categories;
	int			c;
	int			c2;
	cat_t		cat;

	/* avoid making error situations worse */
	if (p->error != 0)
		return;

	for (c = CHAR_MIN; c <= CHAR_MAX; c++)
		if (cats[c] == 0 && isinsets(g, c))
		{
			cat = g->ncategories++;
			cats[c] = cat;
			for (c2 = c + 1; c2 <= CHAR_MAX; c2++)
				if (cats[c2] == 0 && samesets(g, c, c2))
					cats[c2] = cat;
		}
}

/*
 - dupl - emit a duplicate of a bunch of sops
 == static sopno dupl(struct parse *p, sopno start, sopno finish);
 */
static sopno					/* start of duplicate */
dupl(p, start, finish)
struct parse *p;
sopno		start;				/* from here */
sopno		finish;				/* to this less one */
{
	sopno		ret = HERE();
	sopno		len = finish - start;

	assert(finish >= start);
	if (len == 0)
		return ret;
	enlarge(p, p->ssize + len); /* this many unexpected additions */
	assert(p->ssize >= p->slen + len);
	memcpy((char *) (p->strip + p->slen),
		   (char *) (p->strip + start), (size_t) len * sizeof(sop));
	p->slen += len;
	return ret;
}

/*
 - doemit - emit a strip operator
 == static void doemit(struct parse *p, sop op, size_t opnd);
 *
 * It might seem better to implement this as a macro with a function as
 * hard-case backup, but it's just too big and messy unless there are
 * some changes to the data structures.  Maybe later.
 */
static void
doemit(p, op, opnd)
struct parse *p;
sop			op;
size_t		opnd;
{
	/* avoid making error situations worse */
	if (p->error != 0)
		return;

	/* deal with oversize operands ("can't happen", more or less) */
	assert(opnd < 1 << OPSHIFT);

	/* deal with undersized strip */
	if (p->slen >= p->ssize)
		enlarge(p, (p->ssize + 1) / 2 * 3);		/* +50% */
	assert(p->slen < p->ssize);

	/* finally, it's all reduced to the easy case */
	p->strip[p->slen++] = SOP(op, opnd);
}

/*
 - doinsert - insert a sop into the strip
 == static void doinsert(struct parse *p, sop op, size_t opnd, sopno pos);
 */
static void
doinsert(p, op, opnd, pos)
struct parse *p;
sop			op;
size_t		opnd;
sopno		pos;
{
	sopno		sn;
	sop			s;
	int			i;

	/* avoid making error situations worse */
	if (p->error != 0)
		return;

	sn = HERE();
	EMIT(op, opnd);				/* do checks, ensure space */
	assert(HERE() == sn + 1);
	s = p->strip[sn];

	/* adjust paren pointers */
	assert(pos > 0);
	for (i = 1; i < NPAREN; i++)
	{
		if (p->pbegin[i] >= pos)
			p->pbegin[i]++;
		if (p->pend[i] >= pos)
			p->pend[i]++;
	}

	memmove((char *) &p->strip[pos + 1], (char *) &p->strip[pos],
			(HERE() - pos - 1) * sizeof(sop));
	p->strip[pos] = s;
}

/*
 - dofwd - complete a forward reference
 == static void dofwd(struct parse *p, sopno pos, sop value);
 */
static void
dofwd(p, pos, value)
struct parse *p;
sopno		pos;
sop			value;
{
	/* avoid making error situations worse */
	if (p->error != 0)
		return;

	assert(value < 1 << OPSHIFT);
	p->strip[pos] = OP(p->strip[pos]) | value;
}

/*
 - enlarge - enlarge the strip
 == static void enlarge(struct parse *p, sopno size);
 */
static void
enlarge(p, size)
struct parse *p;
sopno		size;
{
	sop		   *sp;

	if (p->ssize >= size)
		return;

	sp = (sop *) realloc(p->strip, size * sizeof(sop));
	if (sp == NULL)
	{
		SETERROR(REG_ESPACE);
		return;
	}
	p->strip = sp;
	p->ssize = size;
}

/*
 - stripsnug - compact the strip
 == static void stripsnug(struct parse *p, struct re_guts *g);
 */
static void
stripsnug(p, g)
struct parse *p;
struct re_guts *g;
{
	g->nstates = p->slen;
	g->strip = (sop *) realloc((char *) p->strip, p->slen * sizeof(sop));
	if (g->strip == NULL)
	{
		SETERROR(REG_ESPACE);
		g->strip = p->strip;
	}
}

/*
 - findmust - fill in must and mlen with longest mandatory literal string
 == static void findmust(struct parse *p, struct re_guts *g);
 *
 * This algorithm could do fancy things like analyzing the operands of |
 * for common subsequences.  Someday.  This code is simple and finds most
 * of the interesting cases.
 *
 * Note that must and mlen got initialized during setup.
 */
static void
findmust(p, g)
struct parse *p;
struct re_guts *g;
{
	sop		   *scan;
	sop		   *start = 0;
	sop		   *newstart = 0;
	sopno		newlen;
	sop			s;
	pg_wchar   *cp;
	sopno		i;

	/* avoid making error situations worse */
	if (p->error != 0)
		return;

	/* find the longest OCHAR sequence in strip */
	newlen = 0;
	scan = g->strip + 1;
	do
	{
		s = *scan++;
		switch (OP(s))
		{
			case OCHAR: /* sequence member */
				if (newlen == 0)/* new sequence */
					newstart = scan - 1;
				newlen++;
				break;
			case OPLUS_:		/* things that don't break one */
			case OLPAREN:
			case ORPAREN:
				break;
			case OQUEST_:		/* things that must be skipped */
			case OCH_:
				scan--;
				do
				{
					scan += OPND(s);
					s = *scan;
					/* assert() interferes w debug printouts */
					if (OP(s) != O_QUEST && OP(s) != O_CH &&
						OP(s) != OOR2)
					{
						g->iflags |= BAD;
						return;
					}
				} while (OP(s) != O_QUEST && OP(s) != O_CH);
				/* fallthrough */
			default:			/* things that break a sequence */
				if (newlen > g->mlen)
				{				/* ends one */
					start = newstart;
					g->mlen = newlen;
				}
				newlen = 0;
				break;
		}
	} while (OP(s) != OEND);

	if (g->mlen == 0)			/* there isn't one */
		return;

	/* turn it into a character string */
#ifdef MULTIBYTE
	g->must = (pg_wchar *) malloc((size_t) (g->mlen + 1) * sizeof(pg_wchar));
#else
	g->must = malloc((size_t) g->mlen + 1);
#endif
	if (g->must == NULL)
	{							/* argh; just forget it */
		g->mlen = 0;
		return;
	}
	cp = g->must;
	scan = start;
	for (i = g->mlen; i > 0; i--)
	{
		while (OP(s = *scan++) != OCHAR)
			continue;
		assert(cp < g->must + g->mlen);
		*cp++ = (pg_wchar) OPND(s);
	}
	assert(cp == g->must + g->mlen);
	*cp++ = '\0';				/* just on general principles */
}

/*
 - pluscount - count + nesting
 == static sopno pluscount(struct parse *p, struct re_guts *g);
 */
static sopno					/* nesting depth */
pluscount(p, g)
struct parse *p;
struct re_guts *g;
{
	sop		   *scan;
	sop			s;
	sopno		plusnest = 0;
	sopno		maxnest = 0;

	if (p->error != 0)
		return 0;				/* there may not be an OEND */

	scan = g->strip + 1;
	do
	{
		s = *scan++;
		switch (OP(s))
		{
			case OPLUS_:
				plusnest++;
				break;
			case O_PLUS:
				if (plusnest > maxnest)
					maxnest = plusnest;
				plusnest--;
				break;
		}
	} while (OP(s) != OEND);
	if (plusnest != 0)
		g->iflags |= BAD;
	return maxnest;
}

/*
 * some ctype functions with none-ascii-char guard
 */
static int
pg_isdigit(int c)
{
#ifdef MULTIBYTE
	return (c >= 0 && c <= UCHAR_MAX && isdigit(c));
#else
	return (isdigit(c));
#endif
}

static int
pg_isalpha(int c)
{
#ifdef MULTIBYTE
	return (c >= 0 && c <= UCHAR_MAX && isalpha(c));
#else
	return (isalpha(c));
#endif
}

static int
pg_isupper(int c)
{
#ifdef MULTIBYTE
	return (c >= 0 && c <= UCHAR_MAX && isupper(c));
#else
	return (isupper(c));
#endif
}

static int
pg_islower(int c)
{
#ifdef MULTIBYTE
	return (c >= 0 && c <= UCHAR_MAX && islower(c));
#else
	return (islower(c));
#endif
}
