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[apple/libc.git] / regex / regcomp-fbsd.c
diff --git a/regex/regcomp-fbsd.c b/regex/regcomp-fbsd.c
new file mode 100644 (file)
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--- /dev/null
@@ -0,0 +1,1946 @@
+/*-
+ * 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/cdefs.h>
+__FBSDID("$FreeBSD: src/lib/libc/regex/regcomp.c,v 1.34 2004/10/03 15:42:59 stefanf Exp $");
+
+#include "xlocale_private.h"
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <regex.h>
+#include <runetype.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "collate.h"
+
+#include "utils.h"
+#include "regex2.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 */
+#if __DARWIN_UNIX03
+       int zerorepeats;
+#endif /* __DARWIN_UNIX03 */
+       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, wint_t stop);
+static void p_ere_exp(struct parse *p);
+static void p_str(struct parse *p);
+static void p_bre(struct parse *p, wint_t end1, wint_t 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 wint_t p_b_symbol(struct parse *p);
+static wint_t p_b_coll_elem(struct parse *p, wint_t endc);
+static wint_t othercase(wint_t ch, locale_t loc);
+static void bothcases(struct parse *p, wint_t ch);
+static void ordinary(struct parse *p, wint_t 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 void CHadd(struct parse *p, cset *cs, wint_t ch);
+static void CHaddrange(struct parse *p, cset *cs, wint_t min, wint_t max);
+static void CHaddtype(struct parse *p, cset *cs, wctype_t wct);
+static wint_t singleton(cset *cs, locale_t loc);
+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 int altoffset(sop *scan, int offset);
+static void computejumps(struct parse *p, struct re_guts *g);
+static void computematchjumps(struct parse *p, struct re_guts *g);
+static sopno pluscount(struct parse *p, struct re_guts *g);
+static wint_t wgetnext(struct parse *p);
+
+#ifdef __cplusplus
+}
+#endif
+/* ========= end header generated by ./mkh ========= */
+
+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        WGETNEXT()      wgetnext(p)
+#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
+
+/* Macro used by computejump()/computematchjump() */
+#define MIN(a,b)       ((a)<(b)?(a):(b))
+
+/*
+ - 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 */
+regcomp(preg, pattern, cflags)
+regex_t * __restrict preg;
+const char * __restrict pattern;
+int cflags;
+{
+       struct parse pa;
+       struct re_guts *g;
+       struct parse *p = &pa;
+       int i;
+       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));
+       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;
+#if __DARWIN_UNIX03
+       p->zerorepeats = 0;
+#endif /* __DARWIN_UNIX03 */
+       for (i = 0; i < NPAREN; i++) {
+               p->pbegin[i] = 0;
+               p->pend[i] = 0;
+       }
+       g->loc = __current_locale();
+       g->sets = NULL;
+       g->ncsets = 0;
+       g->cflags = cflags;
+       g->iflags = 0;
+       g->nbol = 0;
+       g->neol = 0;
+       g->must = NULL;
+       g->moffset = -1;
+       g->charjump = NULL;
+       g->matchjump = NULL;
+       g->mlen = 0;
+       g->nsub = 0;
+       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 */
+       stripsnug(p, g);
+       findmust(p, g);
+       /* only use Boyer-Moore algorithm if the pattern is bigger
+        * than three characters
+        */
+       if(g->mlen > 3) {
+               computejumps(p, g);
+               computematchjumps(p, g);
+               if(g->matchjump == NULL && g->charjump != NULL) {
+                       free(g->charjump);
+                       g->charjump = NULL;
+               }
+       }
+       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 */
+               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;
+       sopno prevfwd;
+       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);
+#if __DARWIN_UNIX03
+               if (!p->zerorepeats) REQUIRE(HERE() != conc, REG_EMPTY);        /* require nonempty */
+               else p->zerorepeats--;
+#else
+               (void)REQUIRE(HERE() != conc, REG_EMPTY);       /* require nonempty */
+#endif
+               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;
+{
+       char c;
+       wint_t wc;
+       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 '(':
+               (void)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);
+               (void)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 '\\':
+               (void)REQUIRE(MORE(), REG_EESCAPE);
+               wc = WGETNEXT();
+               ordinary(p, wc);
+               break;
+       case '{':               /* okay as ordinary except if digit follows */
+               (void)REQUIRE(!MORE() || !isdigit_l((uch)PEEK(), p->g->loc), REG_BADRPT);
+               /* FALLTHROUGH */
+       default:
+               p->next--;
+               wc = WGETNEXT();
+               ordinary(p, wc);
+               break;
+       }
+
+       if (!MORE())
+               return;
+       c = PEEK();
+       /* we call { a repetition if followed by a digit */
+       if (!( c == '*' || c == '+' || c == '?' ||
+                               (c == '{' && MORE2() && isdigit_l((uch)PEEK2(), p->g->loc)) ))
+               return;         /* no repetition, we're done */
+       NEXT();
+
+       (void)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_l((uch)PEEK(), p->g->loc)) {
+                               count2 = p_count(p);
+                               (void)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();
+                       (void)REQUIRE(MORE(), REG_EBRACE);
+                       SETERROR(REG_BADBR);
+               }
+               break;
+       }
+
+       if (!MORE())
+               return;
+       c = PEEK();
+       if (!( c == '*' || c == '+' || c == '?' ||
+                               (c == '{' && MORE2() && isdigit_l((uch)PEEK2(), p->g->loc)) ) )
+               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;
+{
+#if __DARWIN_UNIX03
+       if (!p->zerorepeats) REQUIRE(MORE(), REG_EMPTY);
+       else p->zerorepeats--;
+#else  /* !__DARWIN_UNIX03 */
+       (void)REQUIRE(MORE(), REG_EMPTY);
+#endif /* __DARWIN_UNIX03 */
+       while (MORE())
+               ordinary(p, WGETNEXT());
+}
+
+/*
+ - 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 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++;
+       }
+#if __DARWIN_UNIX03
+       if (!p->zerorepeats) REQUIRE(HERE() != start, REG_EMPTY);       /* require nonempty */
+       else p->zerorepeats--;
+#else  /* !__DARWIN_UNIX03 */
+       (void)REQUIRE(HERE() != start, REG_EMPTY);      /* require nonempty */
+#endif /* __DARWIN_UNIX03 */
+}
+
+/*
+ - 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;
+       wint_t wc;
+       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 == '\\') {
+               (void)REQUIRE(MORE(), REG_EESCAPE);
+               c = BACKSL | 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);
+               (void)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) {
+#if __DARWIN_UNIX03
+                       int skip = 1;
+#endif /* __DARWIN_UNIX03 */
+                       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);
+#if __DARWIN_UNIX03
+                       if (OP(p->strip[p->pbegin[i]+skip]) == OBOL) {
+                               skip++;         /* don't dup anchor in subexp */
+                       }
+                       (void) dupl(p, p->pbegin[i]+skip, p->pend[i]);
+#else  /* !__DARWIN_UNIX03 */
+                       (void) dupl(p, p->pbegin[i]+1, p->pend[i]);
+#endif /* __DARWIN_UNIX03 */
+                       EMIT(O_BACK, i);
+               } else
+                       SETERROR(REG_ESUBREG);
+               p->g->backrefs = 1;
+               break;
+       case '*':
+               (void)REQUIRE(starordinary, REG_BADRPT);
+               /* FALLTHROUGH */
+       default:
+               p->next--;
+               wc = WGETNEXT();
+               ordinary(p, wc);
+               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('\\', '{')) {
+               (void)REQUIRE(MORE(), REG_EBRACE);
+               count = p_count(p);
+               if (EAT(',')) {
+                       if (MORE() && isdigit_l((uch)PEEK(), p->g->loc)) {
+                               count2 = p_count(p);
+                               (void)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();
+                       (void)REQUIRE(MORE(), REG_EBRACE);
+                       SETERROR(REG_BADBR);
+               }
+       } else if (c == '$')     /* $ (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() && isdigit_l((uch)PEEK(), p->g->loc) && count <= DUPMAX) {
+               count = count*10 + (GETNEXT() - '0');
+               ndigits++;
+       }
+
+       (void)REQUIRE(ndigits > 0 && count <= DUPMAX, REG_BADBR);
+       return(count);
+}
+
+/*
+ - p_bracket - parse a bracketed character list
+ == static void p_bracket(struct parse *p);
+ */
+static void
+p_bracket(p)
+struct parse *p;
+{
+       cset *cs;
+       wint_t ch;
+
+       /* 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 ((cs = allocset(p)) == NULL)
+               return;
+
+       if (p->g->cflags&REG_ICASE)
+               cs->icase = 1;
+       if (EAT('^'))
+               cs->invert = 1;
+#if __DARWIN_UNIX03
+       if (PEEK2() != '-' && PEEK2() != ']') { /* Don't eat '-' or ']' if they're part of ranges
+                                                * but do process [^-] */
+       if (EAT(']'))
+               CHadd(p, cs, ']');
+       else if (EAT('-'))
+               CHadd(p, cs, '-');
+       }
+       if (MORE() && !SEETWO('-',']')) /* Parse RE []-'] */
+               p_b_term(p, cs);
+#else /* !__DARWIN_UNIX03 */
+       if (EAT(']'))
+               CHadd(p, cs, ']');
+       else if (EAT('-'))
+               CHadd(p, cs, '-');
+#endif /* __DARWIN_UNIX03 */
+       while (MORE() && PEEK() != ']' && !SEETWO('-', ']'))
+               p_b_term(p, cs);
+       if (EAT('-'))
+               CHadd(p, cs, '-');
+       (void)MUSTEAT(']', REG_EBRACK);
+
+       if (p->error != 0)      /* don't mess things up further */
+               return;
+
+       if (cs->invert && p->g->cflags&REG_NEWLINE)
+               cs->bmp['\n' >> 3] |= 1 << ('\n' & 7);
+
+       if ((ch = singleton(cs, p->g->loc)) != OUT) {   /* optimize singleton sets */
+               ordinary(p, ch);
+               freeset(p, cs);
+       } else
+               EMIT(OANYOF, (int)(cs - p->g->sets));
+}
+
+/*
+ - 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;
+{
+       char c;
+       wint_t start, finish;
+       wint_t i;
+
+       /* classify what we've got */
+       switch ((MORE()) ? PEEK() : '\0') {
+       case '[':
+               c = (MORE2()) ? PEEK2() : '\0';
+               break;
+       case '-':
+#if __DARWIN_UNIX03
+               if (PEEK2() != '-') { /* Allow [---] */
+               SETERROR(REG_ERANGE);
+               return;                 /* NOTE RETURN */
+               } else
+                       c = '-';
+#else  /* !__DARWIN_UNIX03 */
+               SETERROR(REG_ERANGE);
+               return;                 /* NOTE RETURN */
+#endif /* __DARWIN_UNIX03 */
+               break;
+       default:
+               c = '\0';
+               break;
+       }
+
+       switch (c) {
+       case ':':               /* character class */
+               NEXT2();
+               (void)REQUIRE(MORE(), REG_EBRACK);
+               c = PEEK();
+               (void)REQUIRE(c != '-' && c != ']', REG_ECTYPE);
+               p_b_cclass(p, cs);
+               (void)REQUIRE(MORE(), REG_EBRACK);
+               (void)REQUIRE(EATTWO(':', ']'), REG_ECTYPE);
+               break;
+       case '=':               /* equivalence class */
+               NEXT2();
+               (void)REQUIRE(MORE(), REG_EBRACK);
+               c = PEEK();
+#if __DARWIN_UNIX03
+               REQUIRE(c != '-', REG_ECOLLATE); /* allow [=]=] */
+#else  /* !__DARWIN_UNIX03 */
+               (void)REQUIRE(c != '-' && c != ']', REG_ECOLLATE);
+#endif /* __DARWIN_UNIX03 */
+               p_b_eclass(p, cs);
+               (void)REQUIRE(MORE(), REG_EBRACK);
+               (void)REQUIRE(EATTWO('=', ']'), REG_ECOLLATE);
+               break;
+       default:                /* symbol, ordinary character, or range */
+               start = p_b_symbol(p);
+               if (SEE('-') && MORE2() && PEEK2() != ']') {
+                       /* range */
+                       NEXT();
+                       if (EAT('-'))
+                               finish = '-';
+                       else
+                               finish = p_b_symbol(p);
+               } else
+                       finish = start;
+               if (start == finish)
+                       CHadd(p, cs, start);
+               else {
+                       if (p->g->loc->__collate_load_error) {
+                               (void)REQUIRE((uch)start <= (uch)finish, REG_ERANGE);
+                               CHaddrange(p, cs, start, finish);
+                       } else {
+                               (void)REQUIRE(__collate_range_cmp(start, finish, p->g->loc) <= 0, REG_ERANGE);
+                               for (i = 0; i <= UCHAR_MAX; i++) {
+                                       if (   __collate_range_cmp(start, i, p->g->loc) <= 0
+                                           && __collate_range_cmp(i, finish, p->g->loc) <= 0
+                                          )
+                                               CHadd(p, 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;
+{
+       char *sp = p->next;
+       size_t len;
+       wctype_t wct;
+       char clname[16];
+
+       while (MORE() && isalpha_l((uch)PEEK(), p->g->loc))
+               NEXT();
+       len = p->next - sp;
+       if (len >= sizeof(clname) - 1) {
+               SETERROR(REG_ECTYPE);
+               return;
+       }
+       memcpy(clname, sp, len);
+       clname[len] = '\0';
+       if ((wct = wctype_l(clname, p->g->loc)) == 0) {
+               SETERROR(REG_ECTYPE);
+               return;
+       }
+       CHaddtype(p, cs, wct);
+}
+
+/*
+ - p_b_eclass - parse an equivalence-class name and deal with it
+ == static void p_b_eclass(struct parse *p, cset *cs);
+ */
+static void
+p_b_eclass(p, cs)
+struct parse *p;
+cset *cs;
+{
+       char *sp = p->next;
+       int len, ec;
+       mbstate_t mbs;
+       int *newequiv_classes;
+       wint_t c;
+       while (MORE() && !SEETWO('=', ']'))
+               NEXT();
+       if (!MORE()) {
+               SETERROR(REG_EBRACK);
+               return;
+       }
+       len = p->next - sp;
+       memset(&mbs, 0, sizeof(mbs));
+       ec = __collate_equiv_class(sp, len, &mbs, p->g->loc);
+       if (ec > 0) {
+               newequiv_classes = realloc(cs->equiv_classes,
+                   (cs->nequiv_classes + 1) * sizeof(*cs->equiv_classes));
+               if (newequiv_classes == NULL) {
+                       SETERROR(REG_ESPACE);
+                       return;
+               }
+               cs->equiv_classes = newequiv_classes;
+               cs->equiv_classes[cs->nequiv_classes++] = ec;
+               return;
+       }
+       /* not an equivalence class, so fallback to a collating element */
+       p->next = sp;
+       c = p_b_coll_elem(p, '=');
+       CHadd(p, cs, c);
+}
+
+/*
+ - p_b_symbol - parse a character or [..]ed multicharacter collating symbol
+ == static char p_b_symbol(struct parse *p);
+ */
+static wint_t                  /* value of symbol */
+p_b_symbol(p)
+struct parse *p;
+{
+       wint_t value;
+
+       (void)REQUIRE(MORE(), REG_EBRACK);
+       if (!EATTWO('[', '.'))
+               return(WGETNEXT());
+
+       /* collating symbol */
+       value = p_b_coll_elem(p, '.');
+       (void)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 wint_t                  /* value of collating element */
+p_b_coll_elem(p, endc)
+struct parse *p;
+wint_t endc;                   /* name ended by endc,']' */
+{
+       char *sp = p->next;
+       struct cname *cp;
+       int len;
+       mbstate_t mbs;
+       wchar_t wbuf[16];
+       size_t clen;
+
+       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 */
+       memset(&mbs, 0, sizeof(mbs));
+       clen = __collate_collating_symbol(wbuf, 16, sp, len, &mbs, p->g->loc);
+       if (clen == 1)
+               return (*wbuf);                 /* single character */
+       else if (clen == (size_t)-1)
+               SETERROR(REG_ILLSEQ);
+       else
+               SETERROR(REG_ECOLLATE);         /* neither */
+       return(0);
+}
+
+/*
+ - othercase - return the case counterpart of an alphabetic
+ == static char othercase(int ch, locale_t loc);
+ */
+static wint_t                  /* if no counterpart, return ch */
+othercase(ch, loc)
+wint_t ch;
+locale_t loc;
+{
+       assert(iswalpha_l(ch, loc));
+       if (iswupper_l(ch, loc))
+               return(towlower_l(ch, loc));
+       else if (iswlower_l(ch, loc))
+               return(towupper_l(ch, loc));
+       else                    /* peculiar, but could happen */
+               return(ch);
+}
+
+/*
+ - 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;
+wint_t ch;
+{
+       char *oldnext = p->next;
+       char *oldend = p->end;
+       char bracket[3 + MB_LEN_MAX];
+       size_t n;
+       mbstate_t mbs;
+
+       assert(othercase(ch, p->g->loc) != ch); /* p_bracket() would recurse */
+       p->next = bracket;
+       memset(&mbs, 0, sizeof(mbs));
+       n = wcrtomb_l(bracket, ch, &mbs, p->g->loc);
+       assert(n != (size_t)-1);
+       bracket[n] = ']';
+       bracket[n + 1] = '\0';
+       p->end = bracket+n+1;
+       p_bracket(p);
+       assert(p->next == p->end);
+       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;
+wint_t ch;
+{
+       cset *cs;
+
+       if ((p->g->cflags&REG_ICASE) && iswalpha_l(ch, p->g->loc) && othercase(ch, p->g->loc) != ch)
+               bothcases(p, ch);
+       else if ((ch & OPDMASK) == ch)
+               EMIT(OCHAR, ch);
+       else {
+               /*
+                * Kludge: character is too big to fit into an OCHAR operand.
+                * Emit a singleton set.
+                */
+               if ((cs = allocset(p)) == NULL)
+                       return;
+               CHadd(p, cs, ch);
+               EMIT(OANYOF, (int)(cs - p->g->sets));
+       }
+}
+
+/*
+ - 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;
+{
+       char *oldnext = p->next;
+       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(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 */
+#if __DARWIN_UNIX03
+               p->zerorepeats++;
+#endif /* __DARWIN_UNIX03 */
+               break;
+       case REP(0, INF):               /* as x{1,}? */
+#if __DARWIN_UNIX03
+               /* this case does not require the (y|) trick, noKLUDGE */
+               /* Just like * =+?  */
+               INSERT(OPLUS_, start);
+               ASTERN(O_PLUS, start);
+               INSERT(OQUEST_, start);
+               ASTERN(O_QUEST, start);
+               break;
+#endif /* __DARWIN_UNIX03 */
+       case REP(0, 1):                 /* as x{1,1}? */
+       case REP(0, N):                 /* as x{1,n}? */
+               /* 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} */
+#if __DARWIN_UNIX03
+               INSERT(OQUEST_, start);
+               ASTERN(O_QUEST, start);
+#else /* !__DARWIN_UNIX03 */
+               /* 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());
+#endif /* __DARWIN_UNIX03 */
+               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;
+       }
+}
+
+/*
+ - wgetnext - helper function for WGETNEXT() macro. Gets the next wide
+ - character from the parse struct, signals a REG_ILLSEQ error if the
+ - character can't be converted. Returns the number of bytes consumed.
+ */
+static wint_t
+wgetnext(p)
+struct parse *p;
+{
+       mbstate_t mbs;
+       wchar_t wc;
+       size_t n;
+
+       memset(&mbs, 0, sizeof(mbs));
+       n = mbrtowc_l(&wc, p->next, p->end - p->next, &mbs, p->g->loc);
+       if (n == (size_t)-1 || n == (size_t)-2) {
+               SETERROR(REG_ILLSEQ);
+               return (0);
+       }
+       if (n == 0)
+               n = 1;
+       p->next += n;
+       return (wc);
+}
+
+/*
+ - 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;
+{
+       cset *cs, *ncs;
+
+       ncs = realloc(p->g->sets, (p->g->ncsets + 1) * sizeof(*ncs));
+       if (ncs == NULL) {
+               SETERROR(REG_ESPACE);
+               return (NULL);
+       }
+       p->g->sets = ncs;
+       cs = &p->g->sets[p->g->ncsets++];
+       memset(cs, 0, sizeof(*cs));
+
+       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;
+{
+       cset *top = &p->g->sets[p->g->ncsets];
+
+       free(cs->wides);
+       free(cs->ranges);
+       free(cs->types);
+       memset(cs, 0, sizeof(*cs));
+       if (cs == top-1)        /* recover only the easy case */
+               p->g->ncsets--;
+}
+
+/*
+ - singleton - Determine whether a set contains only one character,
+ - returning it if so, otherwise returning OUT.
+ */
+static wint_t
+singleton(cs, loc)
+cset *cs;
+locale_t loc;
+{
+       wint_t i, s, n;
+
+       for (i = n = 0; i < NC; i++)
+               if (CHIN(cs, i, loc)) {
+                       n++;
+                       s = i;
+               }
+       if (n == 1)
+               return (s);
+       if (cs->nwides == 1 && cs->nranges == 0 && cs->ntypes == 0 &&
+           cs->icase == 0)
+               return (cs->wides[0]);
+       /* Don't bother handling the other cases. */
+       return (OUT);
+}
+
+/*
+ - CHadd - add character to character set.
+ */
+static void
+CHadd(p, cs, ch)
+struct parse *p;
+cset *cs;
+wint_t ch;
+{
+       wint_t nch, *newwides;
+       assert(ch >= 0);
+       if (ch < NC)
+               cs->bmp[ch >> 3] |= 1 << (ch & 7);
+       else {
+               newwides = realloc(cs->wides, (cs->nwides + 1) *
+                   sizeof(*cs->wides));
+               if (newwides == NULL) {
+                       SETERROR(REG_ESPACE);
+                       return;
+               }
+               cs->wides = newwides;
+               cs->wides[cs->nwides++] = ch;
+       }
+       if (cs->icase) {
+               if ((nch = towlower_l(ch, p->g->loc)) < NC)
+                       cs->bmp[nch >> 3] |= 1 << (nch & 7);
+               if ((nch = towupper_l(ch, p->g->loc)) < NC)
+                       cs->bmp[nch >> 3] |= 1 << (nch & 7);
+       }
+}
+
+/*
+ - CHaddrange - add all characters in the range [min,max] to a character set.
+ */
+static void
+CHaddrange(p, cs, min, max)
+struct parse *p;
+cset *cs;
+wint_t min, max;
+{
+       crange *newranges;
+
+       for (; min < NC && min <= max; min++)
+               CHadd(p, cs, min);
+       if (min >= max)
+               return;
+       newranges = realloc(cs->ranges, (cs->nranges + 1) *
+           sizeof(*cs->ranges));
+       if (newranges == NULL) {
+               SETERROR(REG_ESPACE);
+               return;
+       }
+       cs->ranges = newranges;
+       cs->ranges[cs->nranges].min = min;
+       cs->ranges[cs->nranges].min = max;
+       cs->nranges++;
+}
+
+/*
+ - CHaddtype - add all characters of a certain type to a character set.
+ */
+static void
+CHaddtype(p, cs, wct)
+struct parse *p;
+cset *cs;
+wctype_t wct;
+{
+       wint_t i;
+       wctype_t *newtypes;
+
+       for (i = 0; i < NC; i++)
+               if (iswctype_l(i, wct, p->g->loc))
+                       CHadd(p, cs, i);
+       newtypes = realloc(cs->types, (cs->ntypes + 1) *
+           sizeof(*cs->types));
+       if (newtypes == NULL) {
+               SETERROR(REG_ESPACE);
+               return;
+       }
+       cs->types = newtypes;
+       cs->types[cs->ntypes++] = wct;
+}
+
+/*
+ - 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);
+       (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(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;
+       sop *newstart;
+       sopno newlen;
+       sop s;
+       char *cp;
+       int offset;
+       char buf[MB_LEN_MAX];
+       size_t clen;
+       mbstate_t mbs;
+       struct __xlocale_st_runelocale *rl = p->g->loc->__lc_ctype;
+
+       /* avoid making error situations worse */
+       if (p->error != 0)
+               return;
+
+       /*
+        * It's not generally safe to do a ``char'' substring search on
+        * multibyte character strings, but it's safe for at least
+        * UTF-8 (see RFC 3629).
+        */
+       if (rl->__mb_cur_max > 1 &&
+           strcmp(rl->_CurrentRuneLocale.__encoding, "UTF-8") != 0)
+               return;
+
+       /* find the longest OCHAR sequence in strip */
+       newlen = 0;
+       offset = 0;
+       g->moffset = 0;
+       scan = g->strip + 1;
+       do {
+               s = *scan++;
+               switch (OP(s)) {
+               case OCHAR:             /* sequence member */
+                       if (newlen == 0) {              /* new sequence */
+                               memset(&mbs, 0, sizeof(mbs));
+                               newstart = scan - 1;
+                       }
+                       clen = wcrtomb_l(buf, OPND(s), &mbs, p->g->loc);
+                       if (clen == (size_t)-1)
+                               goto toohard;
+                       newlen += clen;
+                       break;
+               case OPLUS_:            /* things that don't break one */
+               case OLPAREN:
+               case ORPAREN:
+                       break;
+               case OQUEST_:           /* things that must be skipped */
+               case OCH_:
+                       offset = altoffset(scan, offset);
+                       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 */
+               case OBOW:              /* things that break a sequence */
+               case OEOW:
+               case OBOL:
+               case OEOL:
+               case O_QUEST:
+               case O_CH:
+               case OEND:
+                       if (newlen > g->mlen) {         /* ends one */
+                               start = newstart;
+                               g->mlen = newlen;
+                               if (offset > -1) {
+                                       g->moffset += offset;
+                                       offset = newlen;
+                               } else
+                                       g->moffset = offset;
+                       } else {
+                               if (offset > -1)
+                                       offset += newlen;
+                       }
+                       newlen = 0;
+                       break;
+               case OANY:
+                       if (newlen > g->mlen) {         /* ends one */
+                               start = newstart;
+                               g->mlen = newlen;
+                               if (offset > -1) {
+                                       g->moffset += offset;
+                                       offset = newlen;
+                               } else
+                                       g->moffset = offset;
+                       } else {
+                               if (offset > -1)
+                                       offset += newlen;
+                       }
+                       if (offset > -1)
+                               offset++;
+                       newlen = 0;
+                       break;
+               case OANYOF:            /* may or may not invalidate offset */
+                       /* First, everything as OANY */
+                       if (newlen > g->mlen) {         /* ends one */
+                               start = newstart;
+                               g->mlen = newlen;
+                               if (offset > -1) {
+                                       g->moffset += offset;
+                                       offset = newlen;
+                               } else
+                                       g->moffset = offset;
+                       } else {
+                               if (offset > -1)
+                                       offset += newlen;
+                       }
+                       if (offset > -1)
+                               offset++;
+                       newlen = 0;
+                       break;
+               toohard:
+               default:
+                       /* Anything here makes it impossible or too hard
+                        * to calculate the offset -- so we give up;
+                        * save the last known good offset, in case the
+                        * must sequence doesn't occur later.
+                        */
+                       if (newlen > g->mlen) {         /* ends one */
+                               start = newstart;
+                               g->mlen = newlen;
+                               if (offset > -1)
+                                       g->moffset += offset;
+                               else
+                                       g->moffset = offset;
+                       }
+                       offset = -1;
+                       newlen = 0;
+                       break;
+               }
+       } while (OP(s) != OEND);
+
+       if (g->mlen == 0) {             /* there isn't one */
+               g->moffset = -1;
+               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;
+               g->moffset = -1;
+               return;
+       }
+       cp = g->must;
+       scan = start;
+       memset(&mbs, 0, sizeof(mbs));
+       while (cp < g->must + g->mlen) {
+               while (OP(s = *scan++) != OCHAR)
+                       continue;
+               clen = wcrtomb_l(cp, OPND(s), &mbs, p->g->loc);
+               assert(clen != (size_t)-1);
+               cp += clen;
+       }
+       assert(cp == g->must + g->mlen);
+       *cp++ = '\0';           /* just on general principles */
+}
+
+/*
+ - altoffset - choose biggest offset among multiple choices
+ == static int altoffset(sop *scan, int offset);
+ *
+ * Compute, recursively if necessary, the largest offset among multiple
+ * re paths.
+ */
+static int
+altoffset(scan, offset)
+sop *scan;
+int offset;
+{
+       int largest;
+       int try;
+       sop s;
+
+       /* If we gave up already on offsets, return */
+       if (offset == -1)
+               return -1;
+
+       largest = 0;
+       try = 0;
+       s = *scan++;
+       while (OP(s) != O_QUEST && OP(s) != O_CH) {
+               switch (OP(s)) {
+               case OOR1:
+                       if (try > largest)
+                               largest = try;
+                       try = 0;
+                       break;
+               case OQUEST_:
+               case OCH_:
+                       try = altoffset(scan, try);
+                       if (try == -1)
+                               return -1;
+                       scan--;
+                       do {
+                               scan += OPND(s);
+                               s = *scan;
+                               if (OP(s) != O_QUEST && OP(s) != O_CH &&
+                                                       OP(s) != OOR2)
+                                       return -1;
+                       } while (OP(s) != O_QUEST && OP(s) != O_CH);
+                       /* We must skip to the next position, or we'll
+                        * leave altoffset() too early.
+                        */
+                       scan++;
+                       break;
+               case OANYOF:
+               case OCHAR:
+               case OANY:
+                       try++;
+               case OBOW:
+               case OEOW:
+               case OLPAREN:
+               case ORPAREN:
+               case OOR2:
+                       break;
+               default:
+                       try = -1;
+                       break;
+               }
+               if (try == -1)
+                       return -1;
+               s = *scan++;
+       }
+
+       if (try > largest)
+               largest = try;
+
+       return largest+offset;
+}
+
+/*
+ - computejumps - compute char jumps for BM scan
+ == static void computejumps(struct parse *p, struct re_guts *g);
+ *
+ * This algorithm assumes g->must exists and is has size greater than
+ * zero. It's based on the algorithm found on Computer Algorithms by
+ * Sara Baase.
+ *
+ * A char jump is the number of characters one needs to jump based on
+ * the value of the character from the text that was mismatched.
+ */
+static void
+computejumps(p, g)
+struct parse *p;
+struct re_guts *g;
+{
+       int ch;
+       int mindex;
+
+       /* Avoid making errors worse */
+       if (p->error != 0)
+               return;
+
+       g->charjump = (int*) malloc((NC + 1) * sizeof(int));
+       if (g->charjump == NULL)        /* Not a fatal error */
+               return;
+       /* Adjust for signed chars, if necessary */
+       g->charjump = &g->charjump[-(CHAR_MIN)];
+
+       /* If the character does not exist in the pattern, the jump
+        * is equal to the number of characters in the pattern.
+        */
+       for (ch = CHAR_MIN; ch < (CHAR_MAX + 1); ch++)
+               g->charjump[ch] = g->mlen;
+
+       /* If the character does exist, compute the jump that would
+        * take us to the last character in the pattern equal to it
+        * (notice that we match right to left, so that last character
+        * is the first one that would be matched).
+        */
+       for (mindex = 0; mindex < g->mlen; mindex++)
+               g->charjump[(int)g->must[mindex]] = g->mlen - mindex - 1;
+}
+
+/*
+ - computematchjumps - compute match jumps for BM scan
+ == static void computematchjumps(struct parse *p, struct re_guts *g);
+ *
+ * This algorithm assumes g->must exists and is has size greater than
+ * zero. It's based on the algorithm found on Computer Algorithms by
+ * Sara Baase.
+ *
+ * A match jump is the number of characters one needs to advance based
+ * on the already-matched suffix.
+ * Notice that all values here are minus (g->mlen-1), because of the way
+ * the search algorithm works.
+ */
+static void
+computematchjumps(p, g)
+struct parse *p;
+struct re_guts *g;
+{
+       int mindex;             /* General "must" iterator */
+       int suffix;             /* Keeps track of matching suffix */
+       int ssuffix;            /* Keeps track of suffixes' suffix */
+       int* pmatches;          /* pmatches[k] points to the next i
+                                * such that i+1...mlen is a substring
+                                * of k+1...k+mlen-i-1
+                                */
+
+       /* Avoid making errors worse */
+       if (p->error != 0)
+               return;
+
+       pmatches = (int*) malloc(g->mlen * sizeof(unsigned int));
+       if (pmatches == NULL) {
+               g->matchjump = NULL;
+               return;
+       }
+
+       g->matchjump = (int*) malloc(g->mlen * sizeof(unsigned int));
+       if (g->matchjump == NULL)       /* Not a fatal error */
+               return;
+
+       /* Set maximum possible jump for each character in the pattern */
+       for (mindex = 0; mindex < g->mlen; mindex++)
+               g->matchjump[mindex] = 2*g->mlen - mindex - 1;
+
+       /* Compute pmatches[] */
+       for (mindex = g->mlen - 1, suffix = g->mlen; mindex >= 0;
+           mindex--, suffix--) {
+               pmatches[mindex] = suffix;
+
+               /* If a mismatch is found, interrupting the substring,
+                * compute the matchjump for that position. If no
+                * mismatch is found, then a text substring mismatched
+                * against the suffix will also mismatch against the
+                * substring.
+                */
+               while (suffix < g->mlen
+                   && g->must[mindex] != g->must[suffix]) {
+                       g->matchjump[suffix] = MIN(g->matchjump[suffix],
+                           g->mlen - mindex - 1);
+                       suffix = pmatches[suffix];
+               }
+       }
+
+       /* Compute the matchjump up to the last substring found to jump
+        * to the beginning of the largest must pattern prefix matching
+        * it's own suffix.
+        */
+       for (mindex = 0; mindex <= suffix; mindex++)
+               g->matchjump[mindex] = MIN(g->matchjump[mindex],
+                   g->mlen + suffix - mindex);
+
+        ssuffix = pmatches[suffix];
+        while (suffix < g->mlen) {
+                while (suffix <= ssuffix && suffix < g->mlen) {
+                        g->matchjump[suffix] = MIN(g->matchjump[suffix],
+                           g->mlen + ssuffix - suffix);
+                        suffix++;
+                }
+               if (suffix < g->mlen)
+                       ssuffix = pmatches[ssuffix];
+        }
+
+       free(pmatches);
+}
+
+/*
+ - 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);
+}