]> git.saurik.com Git - apple/libc.git/blobdiff - regex/engine.c
Libc-320.tar.gz
[apple/libc.git] / regex / engine.c
diff --git a/regex/engine.c b/regex/engine.c
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-/*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
- * 
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- * 
- * @APPLE_LICENSE_HEADER_END@
- */
-/*
- * 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.
- */
-
-/*
- * The matching engine and friends.  This file is #included by regexec.c
- * after suitable #defines of a variety of macros used herein, so that
- * different state representations can be used without duplicating masses
- * of code.
- */
-
-#ifdef SNAMES
-#define        matcher smatcher
-#define        fast    sfast
-#define        slow    sslow
-#define        dissect sdissect
-#define        backref sbackref
-#define        step    sstep
-#define        print   sprint
-#define        at      sat
-#define        match   smat
-#endif
-#ifdef LNAMES
-#define        matcher lmatcher
-#define        fast    lfast
-#define        slow    lslow
-#define        dissect ldissect
-#define        backref lbackref
-#define        step    lstep
-#define        print   lprint
-#define        at      lat
-#define        match   lmat
-#endif
-
-/* another structure passed up and down to avoid zillions of parameters */
-struct match {
-       struct re_guts *g;
-       int eflags;
-       regmatch_t *pmatch;     /* [nsub+1] (0 element unused) */
-       char *offp;             /* offsets work from here */
-       char *beginp;           /* start of string -- virtual NUL precedes */
-       char *endp;             /* end of string -- virtual NUL here */
-       char *coldp;            /* can be no match starting before here */
-       char **lastpos;         /* [nplus+1] */
-       STATEVARS;
-       states st;              /* current states */
-       states fresh;           /* states for a fresh start */
-       states tmp;             /* temporary */
-       states empty;           /* empty set of states */
-};
-
-/* ========= begin header generated by ./mkh ========= */
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* === engine.c === */
-static int matcher __P((struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags));
-static char *dissect __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
-static char *backref __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev));
-static char *fast __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
-static char *slow __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
-static states step __P((struct re_guts *g, sopno start, sopno stop, states bef, int ch, states aft));
-#define        BOL     (OUT+1)
-#define        EOL     (BOL+1)
-#define        BOLEOL  (BOL+2)
-#define        NOTHING (BOL+3)
-#define        BOW     (BOL+4)
-#define        EOW     (BOL+5)
-#define        CODEMAX (BOL+5)         /* highest code used */
-#define        NONCHAR(c)      ((c) > CHAR_MAX)
-#define        NNONCHAR        (CODEMAX-CHAR_MAX)
-#ifdef REDEBUG
-static void print __P((struct match *m, char *caption, states st, int ch, FILE *d));
-#endif
-#ifdef REDEBUG
-static void at __P((struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst));
-#endif
-#ifdef REDEBUG
-static char *pchar __P((int ch));
-#endif
-
-#ifdef __cplusplus
-}
-#endif
-/* ========= end header generated by ./mkh ========= */
-
-#ifdef REDEBUG
-#define        SP(t, s, c)     print(m, t, s, c, stdout)
-#define        AT(t, p1, p2, s1, s2)   at(m, t, p1, p2, s1, s2)
-#define        NOTE(str)       { if (m->eflags&REG_TRACE) printf("=%s\n", (str)); }
-#else
-#define        SP(t, s, c)     /* nothing */
-#define        AT(t, p1, p2, s1, s2)   /* nothing */
-#define        NOTE(s) /* nothing */
-#endif
-
-/*
- - matcher - the actual matching engine
- == static int matcher(register struct re_guts *g, char *string, \
- ==    size_t nmatch, regmatch_t pmatch[], int eflags);
- */
-static int                     /* 0 success, REG_NOMATCH failure */
-matcher(g, string, nmatch, pmatch, eflags)
-register struct re_guts *g;
-char *string;
-size_t nmatch;
-regmatch_t pmatch[];
-int eflags;
-{
-       register char *endp;
-       register int i;
-       struct match mv;
-       register struct match *m = &mv;
-       register char *dp;
-       const register sopno gf = g->firststate+1;      /* +1 for OEND */
-       const register sopno gl = g->laststate;
-       char *start;
-       char *stop;
-
-       /* simplify the situation where possible */
-       if (g->cflags&REG_NOSUB)
-               nmatch = 0;
-       if (eflags&REG_STARTEND) {
-               start = string + pmatch[0].rm_so;
-               stop = string + pmatch[0].rm_eo;
-       } else {
-               start = string;
-               stop = start + strlen(start);
-       }
-       if (stop < start)
-               return(REG_INVARG);
-
-       /* prescreening; this does wonders for this rather slow code */
-       if (g->must != NULL) {
-               for (dp = start; dp < stop; dp++)
-                       if (*dp == g->must[0] && stop - dp >= g->mlen &&
-                               memcmp(dp, g->must, (size_t)g->mlen) == 0)
-                               break;
-               if (dp == stop)         /* we didn't find g->must */
-                       return(REG_NOMATCH);
-       }
-
-       /* match struct setup */
-       m->g = g;
-       m->eflags = eflags;
-       m->pmatch = NULL;
-       m->lastpos = NULL;
-       m->offp = string;
-       m->beginp = start;
-       m->endp = stop;
-       STATESETUP(m, 4);
-       SETUP(m->st);
-       SETUP(m->fresh);
-       SETUP(m->tmp);
-       SETUP(m->empty);
-       CLEAR(m->empty);
-
-       /* this loop does only one repetition except for backrefs */
-       for (;;) {
-               endp = fast(m, start, stop, gf, gl);
-               if (endp == NULL) {             /* a miss */
-                       STATETEARDOWN(m);
-                       return(REG_NOMATCH);
-               }
-               if (nmatch == 0 && !g->backrefs)
-                       break;          /* no further info needed */
-
-               /* where? */
-               assert(m->coldp != NULL);
-               for (;;) {
-                       NOTE("finding start");
-                       endp = slow(m, m->coldp, stop, gf, gl);
-                       if (endp != NULL)
-                               break;
-                       assert(m->coldp < m->endp);
-                       m->coldp++;
-               }
-               if (nmatch == 1 && !g->backrefs)
-                       break;          /* no further info needed */
-
-               /* oh my, he wants the subexpressions... */
-               if (m->pmatch == NULL)
-                       m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
-                                                       sizeof(regmatch_t));
-               if (m->pmatch == NULL) {
-                       STATETEARDOWN(m);
-                       return(REG_ESPACE);
-               }
-               for (i = 1; i <= m->g->nsub; i++)
-                       m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
-               if (!g->backrefs && !(m->eflags&REG_BACKR)) {
-                       NOTE("dissecting");
-                       dp = dissect(m, m->coldp, endp, gf, gl);
-               } else {
-                       if (g->nplus > 0 && m->lastpos == NULL)
-                               m->lastpos = (char **)malloc((g->nplus+1) *
-                                                       sizeof(char *));
-                       if (g->nplus > 0 && m->lastpos == NULL) {
-                               free(m->pmatch);
-                               STATETEARDOWN(m);
-                               return(REG_ESPACE);
-                       }
-                       NOTE("backref dissect");
-                       dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
-               }
-               if (dp != NULL)
-                       break;
-
-               /* uh-oh... we couldn't find a subexpression-level match */
-               assert(g->backrefs);    /* must be back references doing it */
-               assert(g->nplus == 0 || m->lastpos != NULL);
-               for (;;) {
-                       if (dp != NULL || endp <= m->coldp)
-                               break;          /* defeat */
-                       NOTE("backoff");
-                       endp = slow(m, m->coldp, endp-1, gf, gl);
-                       if (endp == NULL)
-                               break;          /* defeat */
-                       /* try it on a shorter possibility */
-#ifndef NDEBUG
-                       for (i = 1; i <= m->g->nsub; i++) {
-                               assert(m->pmatch[i].rm_so == -1);
-                               assert(m->pmatch[i].rm_eo == -1);
-                       }
-#endif
-                       NOTE("backoff dissect");
-                       dp = backref(m, m->coldp, endp, gf, gl, (sopno)0);
-               }
-               assert(dp == NULL || dp == endp);
-               if (dp != NULL)         /* found a shorter one */
-                       break;
-
-               /* despite initial appearances, there is no match here */
-               NOTE("false alarm");
-               start = m->coldp + 1;   /* recycle starting later */
-               assert(start <= stop);
-       }
-
-       /* fill in the details if requested */
-       if (nmatch > 0) {
-               pmatch[0].rm_so = m->coldp - m->offp;
-               pmatch[0].rm_eo = endp - m->offp;
-       }
-       if (nmatch > 1) {
-               assert(m->pmatch != NULL);
-               for (i = 1; i < nmatch; i++)
-                       if (i <= m->g->nsub)
-                               pmatch[i] = m->pmatch[i];
-                       else {
-                               pmatch[i].rm_so = -1;
-                               pmatch[i].rm_eo = -1;
-                       }
-       }
-
-       if (m->pmatch != NULL)
-               free((char *)m->pmatch);
-       if (m->lastpos != NULL)
-               free((char *)m->lastpos);
-       STATETEARDOWN(m);
-       return(0);
-}
-
-/*
- - dissect - figure out what matched what, no back references
- == static char *dissect(register struct match *m, char *start, \
- ==    char *stop, sopno startst, sopno stopst);
- */
-static char *                  /* == stop (success) always */
-dissect(m, start, stop, startst, stopst)
-register struct match *m;
-char *start;
-char *stop;
-sopno startst;
-sopno stopst;
-{
-       register int i;
-       register sopno ss;      /* start sop of current subRE */
-       register sopno es;      /* end sop of current subRE */
-       register char *sp;      /* start of string matched by it */
-       register char *stp;     /* string matched by it cannot pass here */
-       register char *rest;    /* start of rest of string */
-       register char *tail;    /* string unmatched by rest of RE */
-       register sopno ssub;    /* start sop of subsubRE */
-       register sopno esub;    /* end sop of subsubRE */
-       register char *ssp;     /* start of string matched by subsubRE */
-       register char *sep;     /* end of string matched by subsubRE */
-       register char *oldssp;  /* previous ssp */
-       register char *dp;
-
-       AT("diss", start, stop, startst, stopst);
-       sp = start;
-       for (ss = startst; ss < stopst; ss = es) {
-               /* identify end of subRE */
-               es = ss;
-               switch (OP(m->g->strip[es])) {
-               case OPLUS_:
-               case OQUEST_:
-                       es += OPND(m->g->strip[es]);
-                       break;
-               case OCH_:
-                       while (OP(m->g->strip[es]) != O_CH)
-                               es += OPND(m->g->strip[es]);
-                       break;
-               }
-               es++;
-
-               /* figure out what it matched */
-               switch (OP(m->g->strip[ss])) {
-               case OEND:
-                       assert(nope);
-                       break;
-               case OCHAR:
-                       sp++;
-                       break;
-               case OBOL:
-               case OEOL:
-               case OBOW:
-               case OEOW:
-                       break;
-               case OANY:
-               case OANYOF:
-                       sp++;
-                       break;
-               case OBACK_:
-               case O_BACK:
-                       assert(nope);
-                       break;
-               /* cases where length of match is hard to find */
-               case OQUEST_:
-                       stp = stop;
-                       for (;;) {
-                               /* how long could this one be? */
-                               rest = slow(m, sp, stp, ss, es);
-                               assert(rest != NULL);   /* it did match */
-                               /* could the rest match the rest? */
-                               tail = slow(m, rest, stop, es, stopst);
-                               if (tail == stop)
-                                       break;          /* yes! */
-                               /* no -- try a shorter match for this one */
-                               stp = rest - 1;
-                               assert(stp >= sp);      /* it did work */
-                       }
-                       ssub = ss + 1;
-                       esub = es - 1;
-                       /* did innards match? */
-                       if (slow(m, sp, rest, ssub, esub) != NULL) {
-                               dp = dissect(m, sp, rest, ssub, esub);
-                               assert(dp == rest);
-                       } else          /* no */
-                               assert(sp == rest);
-                       sp = rest;
-                       break;
-               case OPLUS_:
-                       stp = stop;
-                       for (;;) {
-                               /* how long could this one be? */
-                               rest = slow(m, sp, stp, ss, es);
-                               assert(rest != NULL);   /* it did match */
-                               /* could the rest match the rest? */
-                               tail = slow(m, rest, stop, es, stopst);
-                               if (tail == stop)
-                                       break;          /* yes! */
-                               /* no -- try a shorter match for this one */
-                               stp = rest - 1;
-                               assert(stp >= sp);      /* it did work */
-                       }
-                       ssub = ss + 1;
-                       esub = es - 1;
-                       ssp = sp;
-                       oldssp = ssp;
-                       for (;;) {      /* find last match of innards */
-                               sep = slow(m, ssp, rest, ssub, esub);
-                               if (sep == NULL || sep == ssp)
-                                       break;  /* failed or matched null */
-                               oldssp = ssp;   /* on to next try */
-                               ssp = sep;
-                       }
-                       if (sep == NULL) {
-                               /* last successful match */
-                               sep = ssp;
-                               ssp = oldssp;
-                       }
-                       assert(sep == rest);    /* must exhaust substring */
-                       assert(slow(m, ssp, sep, ssub, esub) == rest);
-                       dp = dissect(m, ssp, sep, ssub, esub);
-                       assert(dp == sep);
-                       sp = rest;
-                       break;
-               case OCH_:
-                       stp = stop;
-                       for (;;) {
-                               /* how long could this one be? */
-                               rest = slow(m, sp, stp, ss, es);
-                               assert(rest != NULL);   /* it did match */
-                               /* could the rest match the rest? */
-                               tail = slow(m, rest, stop, es, stopst);
-                               if (tail == stop)
-                                       break;          /* yes! */
-                               /* no -- try a shorter match for this one */
-                               stp = rest - 1;
-                               assert(stp >= sp);      /* it did work */
-                       }
-                       ssub = ss + 1;
-                       esub = ss + OPND(m->g->strip[ss]) - 1;
-                       assert(OP(m->g->strip[esub]) == OOR1);
-                       for (;;) {      /* find first matching branch */
-                               if (slow(m, sp, rest, ssub, esub) == rest)
-                                       break;  /* it matched all of it */
-                               /* that one missed, try next one */
-                               assert(OP(m->g->strip[esub]) == OOR1);
-                               esub++;
-                               assert(OP(m->g->strip[esub]) == OOR2);
-                               ssub = esub + 1;
-                               esub += OPND(m->g->strip[esub]);
-                               if (OP(m->g->strip[esub]) == OOR2)
-                                       esub--;
-                               else
-                                       assert(OP(m->g->strip[esub]) == O_CH);
-                       }
-                       dp = dissect(m, sp, rest, ssub, esub);
-                       assert(dp == rest);
-                       sp = rest;
-                       break;
-               case O_PLUS:
-               case O_QUEST:
-               case OOR1:
-               case OOR2:
-               case O_CH:
-                       assert(nope);
-                       break;
-               case OLPAREN:
-                       i = OPND(m->g->strip[ss]);
-                       assert(0 < i && i <= m->g->nsub);
-                       m->pmatch[i].rm_so = sp - m->offp;
-                       break;
-               case ORPAREN:
-                       i = OPND(m->g->strip[ss]);
-                       assert(0 < i && i <= m->g->nsub);
-                       m->pmatch[i].rm_eo = sp - m->offp;
-                       break;
-               default:                /* uh oh */
-                       assert(nope);
-                       break;
-               }
-       }
-
-       assert(sp == stop);
-       return(sp);
-}
-
-/*
- - backref - figure out what matched what, figuring in back references
- == static char *backref(register struct match *m, char *start, \
- ==    char *stop, sopno startst, sopno stopst, sopno lev);
- */
-static char *                  /* == stop (success) or NULL (failure) */
-backref(m, start, stop, startst, stopst, lev)
-register struct match *m;
-char *start;
-char *stop;
-sopno startst;
-sopno stopst;
-sopno lev;                     /* PLUS nesting level */
-{
-       register int i;
-       register sopno ss;      /* start sop of current subRE */
-       register char *sp;      /* start of string matched by it */
-       register sopno ssub;    /* start sop of subsubRE */
-       register sopno esub;    /* end sop of subsubRE */
-       register char *ssp;     /* start of string matched by subsubRE */
-       register char *dp;
-       register size_t len;
-       register int hard;
-       register sop s;
-       register regoff_t offsave;
-       register cset *cs;
-
-       AT("back", start, stop, startst, stopst);
-       sp = start;
-
-       /* get as far as we can with easy stuff */
-       hard = 0;
-       for (ss = startst; !hard && ss < stopst; ss++)
-               switch (OP(s = m->g->strip[ss])) {
-               case OCHAR:
-                       if (sp == stop || *sp++ != (char)OPND(s))
-                               return(NULL);
-                       break;
-               case OANY:
-                       if (sp == stop)
-                               return(NULL);
-                       sp++;
-                       break;
-               case OANYOF:
-                       cs = &m->g->sets[OPND(s)];
-                       if (sp == stop || !CHIN(cs, *sp++))
-                               return(NULL);
-                       break;
-               case OBOL:
-                       if ( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
-                                       (sp < m->endp && *(sp-1) == '\n' &&
-                                               (m->g->cflags&REG_NEWLINE)) )
-                               { /* yes */ }
-                       else
-                               return(NULL);
-                       break;
-               case OEOL:
-                       if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
-                                       (sp < m->endp && *sp == '\n' &&
-                                               (m->g->cflags&REG_NEWLINE)) )
-                               { /* yes */ }
-                       else
-                               return(NULL);
-                       break;
-               case OBOW:
-                       if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
-                                       (sp < m->endp && *(sp-1) == '\n' &&
-                                               (m->g->cflags&REG_NEWLINE)) ||
-                                       (sp > m->beginp &&
-                                                       !ISWORD(*(sp-1))) ) &&
-                                       (sp < m->endp && ISWORD(*sp)) )
-                               { /* yes */ }
-                       else
-                               return(NULL);
-                       break;
-               case OEOW:
-                       if (( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
-                                       (sp < m->endp && *sp == '\n' &&
-                                               (m->g->cflags&REG_NEWLINE)) ||
-                                       (sp < m->endp && !ISWORD(*sp)) ) &&
-                                       (sp > m->beginp && ISWORD(*(sp-1))) )
-                               { /* yes */ }
-                       else
-                               return(NULL);
-                       break;
-               case O_QUEST:
-                       break;
-               case OOR1:      /* matches null but needs to skip */
-                       ss++;
-                       s = m->g->strip[ss];
-                       do {
-                               assert(OP(s) == OOR2);
-                               ss += OPND(s);
-                       } while (OP(s = m->g->strip[ss]) != O_CH);
-                       /* note that the ss++ gets us past the O_CH */
-                       break;
-               default:        /* have to make a choice */
-                       hard = 1;
-                       break;
-               }
-       if (!hard) {            /* that was it! */
-               if (sp != stop)
-                       return(NULL);
-               return(sp);
-       }
-       ss--;                   /* adjust for the for's final increment */
-
-       /* the hard stuff */
-       AT("hard", sp, stop, ss, stopst);
-       s = m->g->strip[ss];
-       switch (OP(s)) {
-       case OBACK_:            /* the vilest depths */
-               i = OPND(s);
-               assert(0 < i && i <= m->g->nsub);
-               if (m->pmatch[i].rm_eo == -1)
-                       return(NULL);
-               assert(m->pmatch[i].rm_so != -1);
-               len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
-               assert(stop - m->beginp >= len);
-               if (sp > stop - len)
-                       return(NULL);   /* not enough left to match */
-               ssp = m->offp + m->pmatch[i].rm_so;
-               if (memcmp(sp, ssp, len) != 0)
-                       return(NULL);
-               while (m->g->strip[ss] != SOP(O_BACK, i))
-                       ss++;
-               return(backref(m, sp+len, stop, ss+1, stopst, lev));
-               break;
-       case OQUEST_:           /* to null or not */
-               dp = backref(m, sp, stop, ss+1, stopst, lev);
-               if (dp != NULL)
-                       return(dp);     /* not */
-               return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev));
-               break;
-       case OPLUS_:
-               assert(m->lastpos != NULL);
-               assert(lev+1 <= m->g->nplus);
-               m->lastpos[lev+1] = sp;
-               return(backref(m, sp, stop, ss+1, stopst, lev+1));
-               break;
-       case O_PLUS:
-               if (sp == m->lastpos[lev])      /* last pass matched null */
-                       return(backref(m, sp, stop, ss+1, stopst, lev-1));
-               /* try another pass */
-               m->lastpos[lev] = sp;
-               dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev);
-               if (dp == NULL)
-                       return(backref(m, sp, stop, ss+1, stopst, lev-1));
-               else
-                       return(dp);
-               break;
-       case OCH_:              /* find the right one, if any */
-               ssub = ss + 1;
-               esub = ss + OPND(s) - 1;
-               assert(OP(m->g->strip[esub]) == OOR1);
-               for (;;) {      /* find first matching branch */
-                       dp = backref(m, sp, stop, ssub, esub, lev);
-                       if (dp != NULL)
-                               return(dp);
-                       /* that one missed, try next one */
-                       if (OP(m->g->strip[esub]) == O_CH)
-                               return(NULL);   /* there is none */
-                       esub++;
-                       assert(OP(m->g->strip[esub]) == OOR2);
-                       ssub = esub + 1;
-                       esub += OPND(m->g->strip[esub]);
-                       if (OP(m->g->strip[esub]) == OOR2)
-                               esub--;
-                       else
-                               assert(OP(m->g->strip[esub]) == O_CH);
-               }
-               break;
-       case OLPAREN:           /* must undo assignment if rest fails */
-               i = OPND(s);
-               assert(0 < i && i <= m->g->nsub);
-               offsave = m->pmatch[i].rm_so;
-               m->pmatch[i].rm_so = sp - m->offp;
-               dp = backref(m, sp, stop, ss+1, stopst, lev);
-               if (dp != NULL)
-                       return(dp);
-               m->pmatch[i].rm_so = offsave;
-               return(NULL);
-               break;
-       case ORPAREN:           /* must undo assignment if rest fails */
-               i = OPND(s);
-               assert(0 < i && i <= m->g->nsub);
-               offsave = m->pmatch[i].rm_eo;
-               m->pmatch[i].rm_eo = sp - m->offp;
-               dp = backref(m, sp, stop, ss+1, stopst, lev);
-               if (dp != NULL)
-                       return(dp);
-               m->pmatch[i].rm_eo = offsave;
-               return(NULL);
-               break;
-       default:                /* uh oh */
-               assert(nope);
-               break;
-       }
-
-       /* "can't happen" */
-       assert(nope);
-       /* NOTREACHED */
-}
-
-/*
- - fast - step through the string at top speed
- == static char *fast(register struct match *m, char *start, \
- ==    char *stop, sopno startst, sopno stopst);
- */
-static char *                  /* where tentative match ended, or NULL */
-fast(m, start, stop, startst, stopst)
-register struct match *m;
-char *start;
-char *stop;
-sopno startst;
-sopno stopst;
-{
-       register states st = m->st;
-       register states fresh = m->fresh;
-       register states tmp = m->tmp;
-       register char *p = start;
-       register int c = (start == m->beginp) ? OUT : *(start-1);
-       register int lastc;     /* previous c */
-       register int flagch;
-       register int i;
-       register char *coldp;   /* last p after which no match was underway */
-
-       CLEAR(st);
-       SET1(st, startst);
-       st = step(m->g, startst, stopst, st, NOTHING, st);
-       ASSIGN(fresh, st);
-       SP("start", st, *p);
-       coldp = NULL;
-       for (;;) {
-               /* next character */
-               lastc = c;
-               c = (p == m->endp) ? OUT : *p;
-               if (EQ(st, fresh))
-                       coldp = p;
-
-               /* is there an EOL and/or BOL between lastc and c? */
-               flagch = '\0';
-               i = 0;
-               if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
-                               (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
-                       flagch = BOL;
-                       i = m->g->nbol;
-               }
-               if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
-                               (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
-                       flagch = (flagch == BOL) ? BOLEOL : EOL;
-                       i += m->g->neol;
-               }
-               if (i != 0) {
-                       for (; i > 0; i--)
-                               st = step(m->g, startst, stopst, st, flagch, st);
-                       SP("boleol", st, c);
-               }
-
-               /* how about a word boundary? */
-               if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
-                                       (c != OUT && ISWORD(c)) ) {
-                       flagch = BOW;
-               }
-               if ( (lastc != OUT && ISWORD(lastc)) &&
-                               (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
-                       flagch = EOW;
-               }
-               if (flagch == BOW || flagch == EOW) {
-                       st = step(m->g, startst, stopst, st, flagch, st);
-                       SP("boweow", st, c);
-               }
-
-               /* are we done? */
-               if (ISSET(st, stopst) || p == stop)
-                       break;          /* NOTE BREAK OUT */
-
-               /* no, we must deal with this character */
-               ASSIGN(tmp, st);
-               ASSIGN(st, fresh);
-               assert(c != OUT);
-               st = step(m->g, startst, stopst, tmp, c, st);
-               SP("aft", st, c);
-               assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
-               p++;
-       }
-
-       assert(coldp != NULL);
-       m->coldp = coldp;
-       if (ISSET(st, stopst))
-               return(p+1);
-       else
-               return(NULL);
-}
-
-/*
- - slow - step through the string more deliberately
- == static char *slow(register struct match *m, char *start, \
- ==    char *stop, sopno startst, sopno stopst);
- */
-static char *                  /* where it ended */
-slow(m, start, stop, startst, stopst)
-register struct match *m;
-char *start;
-char *stop;
-sopno startst;
-sopno stopst;
-{
-       register states st = m->st;
-       register states empty = m->empty;
-       register states tmp = m->tmp;
-       register char *p = start;
-       register int c = (start == m->beginp) ? OUT : *(start-1);
-       register int lastc;     /* previous c */
-       register int flagch;
-       register int i;
-       register char *matchp;  /* last p at which a match ended */
-
-       AT("slow", start, stop, startst, stopst);
-       CLEAR(st);
-       SET1(st, startst);
-       SP("sstart", st, *p);
-       st = step(m->g, startst, stopst, st, NOTHING, st);
-       matchp = NULL;
-       for (;;) {
-               /* next character */
-               lastc = c;
-               c = (p == m->endp) ? OUT : *p;
-
-               /* is there an EOL and/or BOL between lastc and c? */
-               flagch = '\0';
-               i = 0;
-               if ( (lastc == '\n' && m->g->cflags&REG_NEWLINE) ||
-                               (lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
-                       flagch = BOL;
-                       i = m->g->nbol;
-               }
-               if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
-                               (c == OUT && !(m->eflags&REG_NOTEOL)) ) {
-                       flagch = (flagch == BOL) ? BOLEOL : EOL;
-                       i += m->g->neol;
-               }
-               if (i != 0) {
-                       for (; i > 0; i--)
-                               st = step(m->g, startst, stopst, st, flagch, st);
-                       SP("sboleol", st, c);
-               }
-
-               /* how about a word boundary? */
-               if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
-                                       (c != OUT && ISWORD(c)) ) {
-                       flagch = BOW;
-               }
-               if ( (lastc != OUT && ISWORD(lastc)) &&
-                               (flagch == EOL || (c != OUT && !ISWORD(c))) ) {
-                       flagch = EOW;
-               }
-               if (flagch == BOW || flagch == EOW) {
-                       st = step(m->g, startst, stopst, st, flagch, st);
-                       SP("sboweow", st, c);
-               }
-
-               /* are we done? */
-               if (ISSET(st, stopst))
-                       matchp = p;
-               if (EQ(st, empty) || p == stop)
-                       break;          /* NOTE BREAK OUT */
-
-               /* no, we must deal with this character */
-               ASSIGN(tmp, st);
-               ASSIGN(st, empty);
-               assert(c != OUT);
-               st = step(m->g, startst, stopst, tmp, c, st);
-               SP("saft", st, c);
-               assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
-               p++;
-       }
-
-       return(matchp);
-}
-
-
-/*
- - step - map set of states reachable before char to set reachable after
- == static states step(register struct re_guts *g, sopno start, sopno stop, \
- ==    register states bef, int ch, register states aft);
- == #define    BOL     (OUT+1)
- == #define    EOL     (BOL+1)
- == #define    BOLEOL  (BOL+2)
- == #define    NOTHING (BOL+3)
- == #define    BOW     (BOL+4)
- == #define    EOW     (BOL+5)
- == #define    CODEMAX (BOL+5)         // highest code used
- == #define    NONCHAR(c)      ((c) > CHAR_MAX)
- == #define    NNONCHAR        (CODEMAX-CHAR_MAX)
- */
-static states
-step(g, start, stop, bef, ch, aft)
-register struct re_guts *g;
-sopno start;                   /* start state within strip */
-sopno stop;                    /* state after stop state within strip */
-register states bef;           /* states reachable before */
-int ch;                                /* character or NONCHAR code */
-register states aft;           /* states already known reachable after */
-{
-       register cset *cs;
-       register sop s;
-       register sopno pc;
-       register onestate here;         /* note, macros know this name */
-       register sopno look;
-       register int i;
-
-       for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
-               s = g->strip[pc];
-               switch (OP(s)) {
-               case OEND:
-                       assert(pc == stop-1);
-                       break;
-               case OCHAR:
-                       /* only characters can match */
-                       assert(!NONCHAR(ch) || ch != (char)OPND(s));
-                       if (ch == (char)OPND(s))
-                               FWD(aft, bef, 1);
-                       break;
-               case OBOL:
-                       if (ch == BOL || ch == BOLEOL)
-                               FWD(aft, bef, 1);
-                       break;
-               case OEOL:
-                       if (ch == EOL || ch == BOLEOL)
-                               FWD(aft, bef, 1);
-                       break;
-               case OBOW:
-                       if (ch == BOW)
-                               FWD(aft, bef, 1);
-                       break;
-               case OEOW:
-                       if (ch == EOW)
-                               FWD(aft, bef, 1);
-                       break;
-               case OANY:
-                       if (!NONCHAR(ch))
-                               FWD(aft, bef, 1);
-                       break;
-               case OANYOF:
-                       cs = &g->sets[OPND(s)];
-                       if (!NONCHAR(ch) && CHIN(cs, ch))
-                               FWD(aft, bef, 1);
-                       break;
-               case OBACK_:            /* ignored here */
-               case O_BACK:
-                       FWD(aft, aft, 1);
-                       break;
-               case OPLUS_:            /* forward, this is just an empty */
-                       FWD(aft, aft, 1);
-                       break;
-               case O_PLUS:            /* both forward and back */
-                       FWD(aft, aft, 1);
-                       i = ISSETBACK(aft, OPND(s));
-                       BACK(aft, aft, OPND(s));
-                       if (!i && ISSETBACK(aft, OPND(s))) {
-                               /* oho, must reconsider loop body */
-                               pc -= OPND(s) + 1;
-                               INIT(here, pc);
-                       }
-                       break;
-               case OQUEST_:           /* two branches, both forward */
-                       FWD(aft, aft, 1);
-                       FWD(aft, aft, OPND(s));
-                       break;
-               case O_QUEST:           /* just an empty */
-                       FWD(aft, aft, 1);
-                       break;
-               case OLPAREN:           /* not significant here */
-               case ORPAREN:
-                       FWD(aft, aft, 1);
-                       break;
-               case OCH_:              /* mark the first two branches */
-                       FWD(aft, aft, 1);
-                       assert(OP(g->strip[pc+OPND(s)]) == OOR2);
-                       FWD(aft, aft, OPND(s));
-                       break;
-               case OOR1:              /* done a branch, find the O_CH */
-                       if (ISSTATEIN(aft, here)) {
-                               for (look = 1;
-                                               OP(s = g->strip[pc+look]) != O_CH;
-                                               look += OPND(s))
-                                       assert(OP(s) == OOR2);
-                               FWD(aft, aft, look);
-                       }
-                       break;
-               case OOR2:              /* propagate OCH_'s marking */
-                       FWD(aft, aft, 1);
-                       if (OP(g->strip[pc+OPND(s)]) != O_CH) {
-                               assert(OP(g->strip[pc+OPND(s)]) == OOR2);
-                               FWD(aft, aft, OPND(s));
-                       }
-                       break;
-               case O_CH:              /* just empty */
-                       FWD(aft, aft, 1);
-                       break;
-               default:                /* ooooops... */
-                       assert(nope);
-                       break;
-               }
-       }
-
-       return(aft);
-}
-
-#ifdef REDEBUG
-/*
- - print - print a set of states
- == #ifdef REDEBUG
- == static void print(struct match *m, char *caption, states st, \
- ==    int ch, FILE *d);
- == #endif
- */
-static void
-print(m, caption, st, ch, d)
-struct match *m;
-char *caption;
-states st;
-int ch;
-FILE *d;
-{
-       register struct re_guts *g = m->g;
-       register int i;
-       register int first = 1;
-
-       if (!(m->eflags&REG_TRACE))
-               return;
-
-       fprintf(d, "%s", caption);
-       if (ch != '\0')
-               fprintf(d, " %s", pchar(ch));
-       for (i = 0; i < g->nstates; i++)
-               if (ISSET(st, i)) {
-                       fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
-                       first = 0;
-               }
-       fprintf(d, "\n");
-}
-
-/* 
- - at - print current situation
- == #ifdef REDEBUG
- == static void at(struct match *m, char *title, char *start, char *stop, \
- ==                                            sopno startst, sopno stopst);
- == #endif
- */
-static void
-at(m, title, start, stop, startst, stopst)
-struct match *m;
-char *title;
-char *start;
-char *stop;
-sopno startst;
-sopno stopst;
-{
-       if (!(m->eflags&REG_TRACE))
-               return;
-
-       printf("%s %s-", title, pchar(*start));
-       printf("%s ", pchar(*stop));
-       printf("%ld-%ld\n", (long)startst, (long)stopst);
-}
-
-#ifndef PCHARDONE
-#define        PCHARDONE       /* never again */
-/*
- - pchar - make a character printable
- == #ifdef REDEBUG
- == static char *pchar(int ch);
- == #endif
- *
- * Is this identical to regchar() over in debug.c?  Well, yes.  But a
- * duplicate here avoids having a debugging-capable regexec.o tied to
- * a matching debug.o, and this is convenient.  It all disappears in
- * the non-debug compilation anyway, so it doesn't matter much.
- */
-static char *                  /* -> representation */
-pchar(ch)
-int ch;
-{
-       static char pbuf[10];
-
-       if (isprint(ch) || ch == ' ')
-               sprintf(pbuf, "%c", ch);
-       else
-               sprintf(pbuf, "\\%o", ch);
-       return(pbuf);
-}
-#endif
-#endif
-
-#undef matcher
-#undef fast
-#undef slow
-#undef dissect
-#undef backref
-#undef step
-#undef print
-#undef at
-#undef match