/*-
 * 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.
 */

/*
 * 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.
 */
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include <regex.h>
#include <wchar.h>
#include <wctype.h>

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

static int nope __unused = 0;   /* for use in asserts; shuts lint up */

static __inline size_t
xmbrtowc(wint_t *wi, const char *s, size_t n, mbstate_t *mbs, wint_t dummy)
{
        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);
}

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 states1 long            /* for later use in regexec() decision */
#define states  states1
#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

        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));
}