/* search.c - searching subroutines using dfa, kwset and regex for grep.
   Copyright 1992, 1998, 2000 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
   02111-1307, USA.  */

/* Written August 1992 by Mike Haertel. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/types.h>
#if defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H && defined HAVE_MBRTOWC
/* We can handle multibyte string.  */
# define MBS_SUPPORT
# include <wchar.h>
# include <wctype.h>
#endif

#include "system.h"
#include "grep.h"
#include "regex.h"
#include "dfa.h"
#include "kwset.h"
#include "error.h"
#include "xalloc.h"
#ifdef HAVE_LIBPCRE
# include <pcre.h>
#endif

#define NCHAR (UCHAR_MAX + 1)

/* For -w, we also consider _ to be word constituent.  */
#define WCHAR(C) (ISALNUM(C) || (C) == '_')

/* DFA compiled regexp. */
static struct dfa dfa;

/* The Regex compiled patterns.  */
static struct patterns
{
  /* Regex compiled regexp. */
  struct re_pattern_buffer regexbuf;
  struct re_registers regs; /* This is here on account of a BRAIN-DEAD
			       Q@#%!# library interface in regex.c.  */
} patterns0;

struct patterns *patterns;
size_t pcount;

/* KWset compiled pattern.  For Ecompile and Gcompile, we compile
   a list of strings, at least one of which is known to occur in
   any string matching the regexp. */
static kwset_t kwset;

/* Number of compiled fixed strings known to exactly match the regexp.
   If kwsexec returns < kwset_exact_matches, then we don't need to
   call the regexp matcher at all. */
static int kwset_exact_matches;

#if defined(MBS_SUPPORT)
static char* check_multibyte_string PARAMS ((char const *buf, size_t size));
#endif
static void kwsinit PARAMS ((void));
static void kwsmusts PARAMS ((void));
static void Gcompile PARAMS ((char const *, size_t));
static void Ecompile PARAMS ((char const *, size_t));
static size_t EGexecute PARAMS ((char const *, size_t, size_t *, int ));
static void Fcompile PARAMS ((char const *, size_t));
static size_t Fexecute PARAMS ((char const *, size_t, size_t *, int));
static void Pcompile PARAMS ((char const *, size_t ));
static size_t Pexecute PARAMS ((char const *, size_t, size_t *, int));

void
dfaerror (char const *mesg)
{
  error (2, 0, mesg);
}

static void
kwsinit (void)
{
  static char trans[NCHAR];
  int i;

  if (match_icase)
    for (i = 0; i < NCHAR; ++i)
      trans[i] = TOLOWER (i);