/*      $NetBSD: regexec.c,v 1.26 2021/02/26 19:24:47 christos Exp $    */

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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.
*
*      @(#)regexec.c   8.3 (Berkeley) 3/20/94
*/

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if 0
static char sccsid[] = "@(#)regexec.c   8.3 (Berkeley) 3/20/94";
__FBSDID("$FreeBSD: head/lib/libc/regex/regexec.c 326025 2017-11-20 19:49:47Z pfg $");
#endif
__RCSID("$NetBSD: regexec.c,v 1.26 2021/02/26 19:24:47 christos Exp $");

/*
* the outer shell of regexec()
*
* This file includes engine.c three times, after muchos fiddling with the
* macros that code uses.  This lets the same code operate on two different
* representations for state sets and characters.
*/

#ifndef LIBHACK
#include "namespace.h"
#endif
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include <regex.h>

#if defined(__weak_alias) && !defined(LIBHACK)
__weak_alias(regexec,_regexec)
#endif

#include "utils.h"
#include "regex2.h"

static __inline size_t
xmbrtowc(wint_t *wi, const char *s, size_t n, mbstate_t *mbs, wint_t dummy)
{
#ifdef NLS
       size_t nr;
       wchar_t wc;

       nr = mbrtowc(&wc, s, n, mbs);
       if (wi != NULL)
               *wi = wc;
       if (nr == 0)
               return (1);
       else if (nr == (size_t)-1 || nr == (size_t)-2) {
               memset(mbs, 0, sizeof(*mbs));
               if (wi != NULL)
                       *wi = dummy;
               return (1);
       } else
               return (nr);
#else
       if (wi)
               *wi = *s;
       return 1;
#endif
}

static __inline size_t
xmbrtowc_dummy(wint_t *wi,
               const char *s,
               size_t n __unused,
               mbstate_t *mbs __unused,
               wint_t dummy __unused)
{

       if (wi != NULL)
               *wi = (unsigned char)*s;
       return (1);
}

/* macros for manipulating states, small version */
#define states  long
#define states1 states          /* for later use in regexec() decision */
#define CLEAR(v)        ((v) = 0)
#define SET0(v, n)      ((v) &= ~((unsigned long)1 << (n)))
#define SET1(v, n)      ((v) |= (unsigned long)1 << (n))
#define ISSET(v, n)     (((v) & ((unsigned long)1 << (n))) != 0)
#define ASSIGN(d, s)    ((d) = (s))
#define EQ(a, b)        ((a) == (b))
#define STATEVARS       long dummy      /* dummy version */
#define STATESETUP(m, n)        /* nothing */
#define STATETEARDOWN(m)        /* nothing */
#define SETUP(v)        ((v) = 0)
#define onestate        long
#define INIT(o, n)      ((o) = (unsigned long)1 << (n))
#define INC(o)  ((o) <<= 1)
#define ISSTATEIN(v, o) (((v) & (o)) != 0)
/* some abbreviations; note that some of these know variable names! */
/* do "if I'm here, I can also be there" etc without branches */
#define FWD(dst, src, n)        ((dst) |= ((unsigned long)(src)&(here)) << (n))
#define BACK(dst, src, n)       ((dst) |= ((unsigned long)(src)&(here)) >> (n))
#define ISSETBACK(v, n) (((v) & ((unsigned long)here >> (n))) != 0)
/* no multibyte support */
#define XMBRTOWC        xmbrtowc_dummy
#define ZAPSTATE(mbs)   ((void)(mbs))
/* function names */
#define SNAMES                  /* engine.c looks after details */

#include "engine.c"

/* now undo things */
#undef  states
#undef  CLEAR
#undef  SET0
#undef  SET1
#undef  ISSET
#undef  ASSIGN
#undef  EQ
#undef  STATEVARS
#undef  STATESETUP
#undef  STATETEARDOWN
#undef  SETUP
#undef  onestate
#undef  INIT
#undef  INC
#undef  ISSTATEIN
#undef  FWD
#undef  BACK
#undef  ISSETBACK
#undef  SNAMES
#undef  XMBRTOWC
#undef  ZAPSTATE

/* macros for manipulating states, large version */
#define states  char *
#define CLEAR(v)        memset(v, 0, m->g->nstates)
#define SET0(v, n)      ((v)[n] = 0)
#define SET1(v, n)      ((v)[n] = 1)
#define ISSET(v, n)     ((v)[n])
#define ASSIGN(d, s)    memcpy(d, s, m->g->nstates)
#define EQ(a, b)        (memcmp(a, b, m->g->nstates) == 0)
#define STATEVARS       long vn; char *space
#define STATESETUP(m, nv)       { (m)->space = malloc((nv)*(m)->g->nstates); \
                               if ((m)->space == NULL) return(REG_ESPACE); \
                               (m)->vn = 0; }
#define STATETEARDOWN(m)        { free((m)->space); }
#define SETUP(v)        ((v) = &m->space[m->vn++ * m->g->nstates])
#define onestate        long
#define INIT(o, n)      ((o) = (n))
#define INC(o)  ((o)++)
#define ISSTATEIN(v, o) ((v)[o])
/* some abbreviations; note that some of these know variable names! */
/* do "if I'm here, I can also be there" etc without branches */
#define FWD(dst, src, n)        ((dst)[here+(n)] |= (src)[here])
#define BACK(dst, src, n)       ((dst)[here-(n)] |= (src)[here])
#define ISSETBACK(v, n) ((v)[here - (n)])
/* no multibyte support */
#define XMBRTOWC        xmbrtowc_dummy
#define ZAPSTATE(mbs)   ((void)(mbs))
/* function names */
#define LNAMES                  /* flag */

#include "engine.c"

/* multibyte character & large states version */
#undef  LNAMES
#undef  XMBRTOWC
#undef  ZAPSTATE
#define XMBRTOWC        xmbrtowc
#define ZAPSTATE(mbs)   memset((mbs), 0, sizeof(*(mbs)))
#define MNAMES

#include "engine.c"

/*
- regexec - interface for matching
= extern int regexec(const regex_t *, const char *, size_t, \
=                                      regmatch_t [], int);
= #define      REG_NOTBOL      00001
= #define      REG_NOTEOL      00002
= #define      REG_STARTEND    00004
= #define      REG_TRACE       00400   // tracing of execution
= #define      REG_LARGE       01000   // force large representation
= #define      REG_BACKR       02000   // force use of backref code
*
* We put this here so we can exploit knowledge of the state representation
* when choosing which matcher to call.  Also, by this point the matchers
* have been prototyped.
*/
int                             /* 0 success, REG_NOMATCH failure */
regexec(const regex_t * __restrict preg,
       const char * __restrict string,
       size_t nmatch,
       regmatch_t pmatch[__restrict],
       int eflags)
{
       struct re_guts *g = preg->re_g;
#ifdef REDEBUG
#       define  GOODFLAGS(f)    (f)
#else
#       define  GOODFLAGS(f)    ((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
#endif
       _DIAGASSERT(preg != NULL);
       _DIAGASSERT(string != NULL);

       if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
               return(REG_BADPAT);
       assert(!(g->iflags&BAD));
       if (g->iflags&BAD)              /* backstop for no-debug case */
               return(REG_BADPAT);
       eflags = GOODFLAGS(eflags);

       if (MB_CUR_MAX > 1)
               return(mmatcher(g, string, nmatch, pmatch, eflags));
       else if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
               return(smatcher(g, string, nmatch, pmatch, eflags));
       else
               return(lmatcher(g, string, nmatch, pmatch, eflags));
}