Initial revision

1 files changed, 1603 insertions, 0 deletions

diff --git a/regex/regcomp.c b/regex/regcomp.c
new file mode 100644
index 0000000..27c5303
--- /dev/null
+++ b/regex/regcomp.c
@@ -0,0 +1,1603 @@
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "utils.h"
+#include "regex2.h"
+
+#include "cclass.h"
+#include "cname.h"
+
+/*
+ * parse structure, passed up and down to avoid global variables and
+ * other clumsinesses
+ */
+struct parse {
+	char *next;		/* next character in RE */
+	char *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) */
+};
+
+#include "regcomp.ih"
+
+static char 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)	((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 notbuiltin_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 */
+notbuiltin_regcomp(preg, pattern, cflags)
+regex_t *preg;
+const char *pattern;
+int cflags;
+{
+	struct parse pa;
+	register struct re_guts *g;
+	register struct parse *p = &pa;
+	register int i;
+	register size_t len;
+#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) {
+		if (preg->re_endp < pattern)
+			return(REG_INVARG);
+		len = preg->re_endp - pattern;
+	} else
+		len = strlen((char *)pattern);
+
+	/* 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;
+	p->next = (char *)pattern;	/* convenience; we do not modify it */
+	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)];
+	(void) 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 */
+		notbuiltin_regfree(preg);
+	return(p->error);
+}
+
+/*
+ - p_ere - ERE parser top level, concatenation and alternation
+ == static void p_ere(register struct parse *p, int stop);
+ */
+static void
+p_ere(p, stop)
+register struct parse *p;
+int stop;			/* character this ERE should end at */
+{
+	register char c;
+	register sopno prevback;
+	register sopno prevfwd;
+	register sopno conc;
+	register 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(register struct parse *p);
+ */
+static void
+p_ere_exp(p)
+register struct parse *p;
+{
+	register char c;
+	register sopno pos;
+	register int count;
+	register int count2;
+	register 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() || !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() && 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 (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() && isdigit(PEEK2())) ) )
+		return;
+	SETERROR(REG_BADRPT);
+}
+
+/*
+ - p_str - string (no metacharacters) "parser"
+ == static void p_str(register struct parse *p);
+ */
+static void
+p_str(p)
+register 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(register struct parse *p, register int end1, \
+ ==	register 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)
+register struct parse *p;
+register int end1;		/* first terminating character */
+register int end2;		/* second terminating character */
+{
+	register sopno start = HERE();
+	register int first = 1;			/* first subexpression? */
+	register 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(register struct parse *p, int starordinary);
+ */
+static int			/* was the simple RE an unbackslashed $? */
+p_simp_re(p, starordinary)
+register struct parse *p;
+int starordinary;		/* is a leading * an ordinary character? */
+{
+	register int c;
+	register int count;
+	register int count2;
+	register sopno pos;
+	register int i;
+	register sopno subno;
+#	define	BACKSL	(1<<CHAR_BIT)
+
+	pos = HERE();		/* repetion op, if any, covers from here */
+
+	assert(MORE());		/* caller should have ensured this */
+	c = GETNEXT();
+	if (c == '\\') {
+		REQUIRE(MORE(), REG_EESCAPE);
+		c = BACKSL | (unsigned char)GETNEXT();
+	}
+	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);
+			(void) 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, (char)c);	/* takes off BACKSL, if any */
+		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() && 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(register struct parse *p);
+ */
+static int			/* the value */
+p_count(p)
+register struct parse *p;
+{
+	register int count = 0;
+	register int ndigits = 0;
+
+	while (MORE() && 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(register 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)
+register struct parse *p;
+{
+	register cset *cs = allocset(p);
+	register int invert = 0;
+
+	/* Dept of Truly Sickening Special-Case Kludges */
+	if (p->next + 5 < p->end && strncmp(p->next, "[:<:]]", 6) == 0) {
+		EMIT(OBOW, 0);
+		NEXTn(6);
+		return;
+	}
+	if (p->next + 5 < p->end && strncmp(p->next, "[:>:]]", 6) == 0) {
+		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) {
+		register int i;
+		register int ci;
+
+		for (i = p->g->csetsize - 1; i >= 0; i--)
+			if (CHIN(cs, i) && isalpha(i)) {
+				ci = othercase(i);
+				if (ci != i)
+					CHadd(cs, ci);
+			}
+		if (cs->multis != NULL)
+			mccase(p, cs);
+	}
+	if (invert) {
+		register 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(register struct parse *p, register cset *cs);
+ */
+static void
+p_b_term(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register char c;
+	register char start, finish;
+	register 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);
+		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(register struct parse *p, register cset *cs);
+ */
+static void
+p_b_cclass(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register char *sp = p->next;
+	register struct cclass *cp;
+	register size_t len;
+	register char *u;
+	register char c;
+
+	while (MORE() && isalpha(PEEK()))
+		NEXT();
+	len = p->next - sp;
+	for (cp = cclasses; cp->name != NULL; cp++)
+		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
+			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(register struct parse *p, register cset *cs);
+ *
+ * This implementation is incomplete. xxx
+ */
+static void
+p_b_eclass(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register 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(register struct parse *p);
+ */
+static char			/* value of symbol */
+p_b_symbol(p)
+register struct parse *p;
+{
+	register char 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(register struct parse *p, int endc);
+ */
+static char			/* value of collating element */
+p_b_coll_elem(p, endc)
+register struct parse *p;
+int endc;			/* name ended by endc,']' */
+{
+	register char *sp = p->next;
+	register struct cname *cp;
+	register 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++)
+		if (strncmp(cp->name, sp, len) == 0 && cp->name[len] == '\0')
+			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);
+ */
+static char			/* if no counterpart, return ch */
+othercase(ch)
+int ch;
+{
+	assert(isalpha(ch));
+	if (isupper(ch))
+		return(tolower(ch));
+	else if (islower(ch))
+		return(toupper(ch));
+	else			/* peculiar, but could happen */
+		return(ch);
+}
+
+/*
+ - bothcases - emit a dualcase version of a two-case character
+ == static void bothcases(register struct parse *p, int ch);
+ *
+ * Boy, is this implementation ever a kludge...
+ */
+static void
+bothcases(p, ch)
+register struct parse *p;
+int ch;
+{
+	register char *oldnext = p->next;
+	register char *oldend = p->end;
+	char 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(register struct parse *p, register int ch);
+ */
+static void
+ordinary(p, ch)
+register struct parse *p;
+register int ch;
+{
+	register cat_t *cap = p->g->categories;
+
+	if ((p->g->cflags&REG_ICASE) && isalpha(ch) && othercase(ch) != ch)
+		bothcases(p, ch);
+	else {
+		EMIT(OCHAR, (unsigned char)ch);
+		if (cap[ch] == 0)
+			cap[ch] = p->g->ncategories++;
+	}
+}
+
+/*
+ - nonnewline - emit REG_NEWLINE version of OANY
+ == static void nonnewline(register struct parse *p);
+ *
+ * Boy, is this implementation ever a kludge...
+ */
+static void
+nonnewline(p)
+register struct parse *p;
+{
+	register char *oldnext = p->next;
+	register char *oldend = p->end;
+	char 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(register struct parse *p, sopno start, int from, int to);
+ */
+static void
+repeat(p, start, from, to)
+register 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) */
+{
+	register 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)
+	register 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(register struct parse *p, int e);
+ */
+static int			/* useless but makes type checking happy */
+seterr(p, e)
+register 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(register struct parse *p);
+ */
+static cset *
+allocset(p)
+register struct parse *p;
+{
+	register int no = p->g->ncsets++;
+	register size_t nc;
+	register size_t nbytes;
+	register cset *cs;
+	register size_t css = (size_t)p->g->csetsize;
+	register 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)
+			(void) 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(register struct parse *p, register cset *cs);
+ */
+static void
+freeset(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register cset *top = &p->g->sets[p->g->ncsets];
+	register 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(register struct parse *p, register 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)
+register struct parse *p;
+register cset *cs;
+{
+	register uch h = cs->hash;
+	register int i;
+	register cset *top = &p->g->sets[p->g->ncsets];
+	register cset *cs2;
+	register 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(register struct parse *p, register cset *cs);
+ */
+static int			/* character; there is no "none" value */
+firstch(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register size_t css = (size_t)p->g->csetsize;
+
+	for (i = 0; i < css; i++)
+		if (CHIN(cs, i))
+			return((char)i);
+	assert(never);
+	return(0);		/* arbitrary */
+}
+
+/*
+ - nch - number of characters in a set
+ == static int nch(register struct parse *p, register cset *cs);
+ */
+static int
+nch(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	register int i;
+	register size_t css = (size_t)p->g->csetsize;
+	register 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(register struct parse *p, register cset *cs, \
+ ==	register char *cp);
+ */
+static void
+mcadd(p, cs, cp)
+register struct parse *p;
+register cset *cs;
+register char *cp;
+{
+	register 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;
+	}
+
+	(void) strcpy(cs->multis + oldend - 1, cp);
+	cs->multis[cs->smultis - 1] = '\0';
+}
+
+/*
+ - mcsub - subtract a collating element from a cset
+ == static void mcsub(register cset *cs, register char *cp);
+ */
+static void
+mcsub(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	register char *fp = mcfind(cs, cp);
+	register size_t len = strlen(fp);
+
+	assert(fp != NULL);
+	(void) 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(register cset *cs, register char *cp);
+ */
+static int
+mcin(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	return(mcfind(cs, cp) != NULL);
+}
+
+/*
+ - mcfind - find a collating element in a cset
+ == static char *mcfind(register cset *cs, register char *cp);
+ */
+static char *
+mcfind(cs, cp)
+register cset *cs;
+register char *cp;
+{
+	register 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(register struct parse *p, register cset *cs);
+ *
+ * This would have to know the set of possibilities.  Implementation
+ * is deferred.
+ */
+static void
+mcinvert(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	assert(cs->multis == NULL);	/* xxx */
+}
+
+/*
+ - mccase - add case counterparts of the list of collating elements in a cset
+ == static void mccase(register struct parse *p, register cset *cs);
+ *
+ * This would have to know the set of possibilities.  Implementation
+ * is deferred.
+ */
+static void
+mccase(p, cs)
+register struct parse *p;
+register cset *cs;
+{
+	assert(cs->multis == NULL);	/* xxx */
+}
+
+/*
+ - isinsets - is this character in any sets?
+ == static int isinsets(register struct re_guts *g, int c);
+ */
+static int			/* predicate */
+isinsets(g, c)
+register struct re_guts *g;
+int c;
+{
+	register uch *col;
+	register int i;
+	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
+	register 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(register struct re_guts *g, int c1, int c2);
+ */
+static int			/* predicate */
+samesets(g, c1, c2)
+register struct re_guts *g;
+int c1;
+int c2;
+{
+	register uch *col;
+	register int i;
+	register int ncols = (g->ncsets+(CHAR_BIT-1)) / CHAR_BIT;
+	register unsigned uc1 = (unsigned char)c1;
+	register 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, register struct re_guts *g);
+ */
+static void
+categorize(p, g)
+struct parse *p;
+register struct re_guts *g;
+{
+	register cat_t *cats = g->categories;
+	register int c;
+	register int c2;
+	register 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(register struct parse *p, sopno start, sopno finish);
+ */
+static sopno			/* start of duplicate */
+dupl(p, start, finish)
+register struct parse *p;
+sopno start;			/* from here */
+sopno finish;			/* to this less one */
+{
+	register sopno ret = HERE();
+	register 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);
+	(void) 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(register 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)
+register 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(register struct parse *p, sop op, size_t opnd, sopno pos);
+ */
+static void
+doinsert(p, op, opnd, pos)
+register struct parse *p;
+sop op;
+size_t opnd;
+sopno pos;
+{
+	register sopno sn;
+	register sop s;
+	register 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(register struct parse *p, sopno pos, sop value);
+ */
+static void
+dofwd(p, pos, value)
+register struct parse *p;
+register 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(register struct parse *p, sopno size);
+ */
+static void
+enlarge(p, size)
+register struct parse *p;
+register sopno size;
+{
+	register 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(register struct parse *p, register struct re_guts *g);
+ */
+static void
+stripsnug(p, g)
+register struct parse *p;
+register 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(register struct parse *p, register 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;
+register struct re_guts *g;
+{
+	register sop *scan;
+	sop *start;
+	register sop *newstart;
+	register sopno newlen;
+	register sop s;
+	register char *cp;
+	register 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 */
+	g->must = malloc((size_t)g->mlen + 1);
+	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++ = (char)OPND(s);
+	}
+	assert(cp == g->must + g->mlen);
+	*cp++ = '\0';		/* just on general principles */
+}
+
+/*
+ - pluscount - count + nesting
+ == static sopno pluscount(register struct parse *p, register struct re_guts *g);
+ */
+static sopno			/* nesting depth */
+pluscount(p, g)
+struct parse *p;
+register struct re_guts *g;
+{
+	register sop *scan;
+	register sop s;
+	register sopno plusnest = 0;
+	register 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);
+}