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/* String search routines for GNU Emacs.
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   Copyright (C) 1985, 1986, 1987, 1993, 1994 Free Software Foundation, Inc.
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This file is part of GNU Emacs.

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

GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
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#include <config.h>
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#include "lisp.h"
#include "syntax.h"
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#include "category.h"
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#include "buffer.h"
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#include "charset.h"
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#include "region-cache.h"
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#include "commands.h"
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#include "blockinput.h"
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#include <sys/types.h>
#include "regex.h"

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#define REGEXP_CACHE_SIZE 20
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/* If the regexp is non-nil, then the buffer contains the compiled form
   of that regexp, suitable for searching.  */
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struct regexp_cache
{
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  struct regexp_cache *next;
  Lisp_Object regexp;
  struct re_pattern_buffer buf;
  char fastmap[0400];
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  /* Nonzero means regexp was compiled to do full POSIX backtracking.  */
  char posix;
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};
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/* The instances of that struct.  */
struct regexp_cache searchbufs[REGEXP_CACHE_SIZE];
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/* The head of the linked list; points to the most recently used buffer.  */
struct regexp_cache *searchbuf_head;
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/* Every call to re_match, etc., must pass &search_regs as the regs
   argument unless you can show it is unnecessary (i.e., if re_match
   is certainly going to be called again before region-around-match
   can be called).

   Since the registers are now dynamically allocated, we need to make
   sure not to refer to the Nth register before checking that it has
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   been allocated by checking search_regs.num_regs.

   The regex code keeps track of whether it has allocated the search
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   buffer using bits in the re_pattern_buffer.  This means that whenever
   you compile a new pattern, it completely forgets whether it has
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   allocated any registers, and will allocate new registers the next
   time you call a searching or matching function.  Therefore, we need
   to call re_set_registers after compiling a new pattern or after
   setting the match registers, so that the regex functions will be
   able to free or re-allocate it properly.  */
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static struct re_registers search_regs;

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/* The buffer in which the last search was performed, or
   Qt if the last search was done in a string;
   Qnil if no searching has been done yet.  */
static Lisp_Object last_thing_searched;
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/* error condition signaled when regexp compile_pattern fails */
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Lisp_Object Qinvalid_regexp;

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static void set_search_regs ();
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static void save_search_regs ();
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static int search_buffer ();

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static void
matcher_overflow ()
{
  error ("Stack overflow in regexp matcher");
}

#ifdef __STDC__
#define CONST const
#else
#define CONST
#endif

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/* Compile a regexp and signal a Lisp error if anything goes wrong.
   PATTERN is the pattern to compile.
   CP is the place to put the result.
   TRANSLATE is a translation table for ignoring case, or NULL for none.
   REGP is the structure that says where to store the "register"
   values that will result from matching this pattern.
   If it is 0, we should compile the pattern not to record any
   subexpression bounds.
   POSIX is nonzero if we want full backtracking (POSIX style)
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   for this pattern.  0 means backtrack only enough to get a valid match.
   MULTIBYTE is nonzero if we want to handle multibyte characters in
   PATTERN.  0 means all multibyte characters are recognized just as
   sequences of binary data.  */
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static void
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compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte)
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     struct regexp_cache *cp;
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     Lisp_Object pattern;
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     Lisp_Object *translate;
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     struct re_registers *regp;
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     int posix;
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     int multibyte;
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{
  CONST char *val;
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  reg_syntax_t old;
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  cp->regexp = Qnil;
  cp->buf.translate = translate;
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  cp->posix = posix;
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  cp->buf.multibyte = multibyte;
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  BLOCK_INPUT;
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  old = re_set_syntax (RE_SYNTAX_EMACS
		       | (posix ? 0 : RE_NO_POSIX_BACKTRACKING));
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  val = (CONST char *) re_compile_pattern ((char *) XSTRING (pattern)->data,
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					   XSTRING (pattern)->size, &cp->buf);
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  re_set_syntax (old);
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  UNBLOCK_INPUT;
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  if (val)
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    Fsignal (Qinvalid_regexp, Fcons (build_string (val), Qnil));
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  cp->regexp = Fcopy_sequence (pattern);
}

/* Compile a regexp if necessary, but first check to see if there's one in
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   the cache.
   PATTERN is the pattern to compile.
   TRANSLATE is a translation table for ignoring case, or NULL for none.
   REGP is the structure that says where to store the "register"
   values that will result from matching this pattern.
   If it is 0, we should compile the pattern not to record any
   subexpression bounds.
   POSIX is nonzero if we want full backtracking (POSIX style)
   for this pattern.  0 means backtrack only enough to get a valid match.  */
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struct re_pattern_buffer *
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compile_pattern (pattern, regp, translate, posix)
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     Lisp_Object pattern;
     struct re_registers *regp;
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     Lisp_Object *translate;
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     int posix;
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{
  struct regexp_cache *cp, **cpp;
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  /* Should we check it here, or add an argument `multibyte' to this
     function?  */
  int multibyte = !NILP (current_buffer->enable_multibyte_characters);
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  for (cpp = &searchbuf_head; ; cpp = &cp->next)
    {
      cp = *cpp;
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      if (XSTRING (cp->regexp)->size == XSTRING (pattern)->size
	  && !NILP (Fstring_equal (cp->regexp, pattern))
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	  && cp->buf.translate == translate
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	  && cp->posix == posix
	  && cp->buf.multibyte == multibyte)
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	break;

      /* If we're at the end of the cache, compile into the last cell.  */
      if (cp->next == 0)
	{
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	  compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte);
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	  break;
	}
    }

  /* When we get here, cp (aka *cpp) contains the compiled pattern,
     either because we found it in the cache or because we just compiled it.
     Move it to the front of the queue to mark it as most recently used.  */
  *cpp = cp->next;
  cp->next = searchbuf_head;
  searchbuf_head = cp;
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  /* Advise the searching functions about the space we have allocated
     for register data.  */
  if (regp)
    re_set_registers (&cp->buf, regp, regp->num_regs, regp->start, regp->end);

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  return &cp->buf;
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}

/* Error condition used for failing searches */
Lisp_Object Qsearch_failed;

Lisp_Object
signal_failure (arg)
     Lisp_Object arg;
{
  Fsignal (Qsearch_failed, Fcons (arg, Qnil));
  return Qnil;
}

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static Lisp_Object
looking_at_1 (string, posix)
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     Lisp_Object string;
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     int posix;
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{
  Lisp_Object val;
  unsigned char *p1, *p2;
  int s1, s2;
  register int i;
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  struct re_pattern_buffer *bufp;
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  if (running_asynch_code)
    save_search_regs ();

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  CHECK_STRING (string, 0);
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  bufp = compile_pattern (string, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
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			   ? DOWNCASE_TABLE : 0),
			  posix);
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  immediate_quit = 1;
  QUIT;			/* Do a pending quit right away, to avoid paradoxical behavior */

  /* Get pointers and sizes of the two strings
     that make up the visible portion of the buffer. */

  p1 = BEGV_ADDR;
  s1 = GPT - BEGV;
  p2 = GAP_END_ADDR;
  s2 = ZV - GPT;
  if (s1 < 0)
    {
      p2 = p1;
      s2 = ZV - BEGV;
      s1 = 0;
    }
  if (s2 < 0)
    {
      s1 = ZV - BEGV;
      s2 = 0;
    }
  
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  i = re_match_2 (bufp, (char *) p1, s1, (char *) p2, s2,
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		  PT - BEGV, &search_regs,
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		  ZV - BEGV);
  if (i == -2)
    matcher_overflow ();

  val = (0 <= i ? Qt : Qnil);
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  for (i = 0; i < search_regs.num_regs; i++)
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    if (search_regs.start[i] >= 0)
      {
	search_regs.start[i] += BEGV;
	search_regs.end[i] += BEGV;
      }
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  XSETBUFFER (last_thing_searched, current_buffer);
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  immediate_quit = 0;
  return val;
}

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DEFUN ("looking-at", Flooking_at, Slooking_at, 1, 1, 0,
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  "Return t if text after point matches regular expression REGEXP.\n\
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This function modifies the match data that `match-beginning',\n\
`match-end' and `match-data' access; save and restore the match\n\
data if you want to preserve them.")
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  (regexp)
     Lisp_Object regexp;
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{
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  return looking_at_1 (regexp, 0);
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}

DEFUN ("posix-looking-at", Fposix_looking_at, Sposix_looking_at, 1, 1, 0,
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  "Return t if text after point matches regular expression REGEXP.\n\
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Find the longest match, in accord with Posix regular expression rules.\n\
This function modifies the match data that `match-beginning',\n\
`match-end' and `match-data' access; save and restore the match\n\
data if you want to preserve them.")
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  (regexp)
     Lisp_Object regexp;
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{
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  return looking_at_1 (regexp, 1);
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}

static Lisp_Object
string_match_1 (regexp, string, start, posix)
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     Lisp_Object regexp, string, start;
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     int posix;
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{
  int val;
  int s;
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  struct re_pattern_buffer *bufp;
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  if (running_asynch_code)
    save_search_regs ();

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  CHECK_STRING (regexp, 0);
  CHECK_STRING (string, 1);

  if (NILP (start))
    s = 0;
  else
    {
      int len = XSTRING (string)->size;

      CHECK_NUMBER (start, 2);
      s = XINT (start);
      if (s < 0 && -s <= len)
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	s = len + s;
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      else if (0 > s || s > len)
	args_out_of_range (string, start);
    }

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  bufp = compile_pattern (regexp, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
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			   ? DOWNCASE_TABLE : 0),
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			  posix);
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  immediate_quit = 1;
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  val = re_search (bufp, (char *) XSTRING (string)->data,
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		   XSTRING (string)->size, s, XSTRING (string)->size - s,
		   &search_regs);
  immediate_quit = 0;
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  last_thing_searched = Qt;
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  if (val == -2)
    matcher_overflow ();
  if (val < 0) return Qnil;
  return make_number (val);
}
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DEFUN ("string-match", Fstring_match, Sstring_match, 2, 3, 0,
  "Return index of start of first match for REGEXP in STRING, or nil.\n\
If third arg START is non-nil, start search at that index in STRING.\n\
For index of first char beyond the match, do (match-end 0).\n\
`match-end' and `match-beginning' also give indices of substrings\n\
matched by parenthesis constructs in the pattern.")
  (regexp, string, start)
     Lisp_Object regexp, string, start;
{
  return string_match_1 (regexp, string, start, 0);
}

DEFUN ("posix-string-match", Fposix_string_match, Sposix_string_match, 2, 3, 0,
  "Return index of start of first match for REGEXP in STRING, or nil.\n\
Find the longest match, in accord with Posix regular expression rules.\n\
If third arg START is non-nil, start search at that index in STRING.\n\
For index of first char beyond the match, do (match-end 0).\n\
`match-end' and `match-beginning' also give indices of substrings\n\
matched by parenthesis constructs in the pattern.")
  (regexp, string, start)
     Lisp_Object regexp, string, start;
{
  return string_match_1 (regexp, string, start, 1);
}

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/* Match REGEXP against STRING, searching all of STRING,
   and return the index of the match, or negative on failure.
   This does not clobber the match data.  */

int
fast_string_match (regexp, string)
     Lisp_Object regexp, string;
{
  int val;
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  struct re_pattern_buffer *bufp;
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  bufp = compile_pattern (regexp, 0, 0, 0);
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  immediate_quit = 1;
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  val = re_search (bufp, (char *) XSTRING (string)->data,
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		   XSTRING (string)->size, 0, XSTRING (string)->size,
		   0);
  immediate_quit = 0;
  return val;
}
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/* Match REGEXP against STRING, searching all of STRING ignoring case,
   and return the index of the match, or negative on failure.
   This does not clobber the match data.  */

extern Lisp_Object Vascii_downcase_table;

int
fast_string_match_ignore_case (regexp, string)
     Lisp_Object regexp;
     char *string;
{
  int val;
  struct re_pattern_buffer *bufp;
  int len = strlen (string);

  bufp = compile_pattern (regexp, 0,
			  XCHAR_TABLE (Vascii_downcase_table)->contents, 0);
  immediate_quit = 1;
  val = re_search (bufp, string, len, 0, len, 0);
  immediate_quit = 0;
  return val;
}
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/* max and min.  */

static int
max (a, b)
     int a, b;
{
  return ((a > b) ? a : b);
}

static int
min (a, b)
     int a, b;
{
  return ((a < b) ? a : b);
}


/* The newline cache: remembering which sections of text have no newlines.  */

/* If the user has requested newline caching, make sure it's on.
   Otherwise, make sure it's off.
   This is our cheezy way of associating an action with the change of
   state of a buffer-local variable.  */
static void
newline_cache_on_off (buf)
     struct buffer *buf;
{
  if (NILP (buf->cache_long_line_scans))
    {
      /* It should be off.  */
      if (buf->newline_cache)
        {
          free_region_cache (buf->newline_cache);
          buf->newline_cache = 0;
        }
    }
  else
    {
      /* It should be on.  */
      if (buf->newline_cache == 0)
        buf->newline_cache = new_region_cache ();
    }
}


/* Search for COUNT instances of the character TARGET between START and END.

   If COUNT is positive, search forwards; END must be >= START.
   If COUNT is negative, search backwards for the -COUNTth instance;
      END must be <= START.
   If COUNT is zero, do anything you please; run rogue, for all I care.

   If END is zero, use BEGV or ZV instead, as appropriate for the
   direction indicated by COUNT.
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   If we find COUNT instances, set *SHORTAGE to zero, and return the
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   position after the COUNTth match.  Note that for reverse motion
   this is not the same as the usual convention for Emacs motion commands.
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   If we don't find COUNT instances before reaching END, set *SHORTAGE
   to the number of TARGETs left unfound, and return END.
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   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
   except when inside redisplay.  */

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scan_buffer (target, start, end, count, shortage, allow_quit)
     register int target;
     int start, end;
     int count;
     int *shortage;
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     int allow_quit;
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{
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  struct region_cache *newline_cache;
  int direction; 
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  if (count > 0)
    {
      direction = 1;
      if (! end) end = ZV;
    }
  else
    {
      direction = -1;
      if (! end) end = BEGV;
    }
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  newline_cache_on_off (current_buffer);
  newline_cache = current_buffer->newline_cache;
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  if (shortage != 0)
    *shortage = 0;

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  immediate_quit = allow_quit;
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  if (count > 0)
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    while (start != end)
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      {
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        /* Our innermost scanning loop is very simple; it doesn't know
           about gaps, buffer ends, or the newline cache.  ceiling is
           the position of the last character before the next such
           obstacle --- the last character the dumb search loop should
           examine.  */
        register int ceiling = end - 1;

        /* If we're looking for a newline, consult the newline cache
           to see where we can avoid some scanning.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_forward
                   (current_buffer, newline_cache, start, &next_change))
              start = next_change;
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            immediate_quit = allow_quit;
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            /* start should never be after end.  */
            if (start >= end)
              start = end - 1;

            /* Now the text after start is an unknown region, and
               next_change is the position of the next known region. */
            ceiling = min (next_change - 1, ceiling);
          }

        /* The dumb loop can only scan text stored in contiguous
           bytes. BUFFER_CEILING_OF returns the last character
           position that is contiguous, so the ceiling is the
           position after that.  */
        ceiling = min (BUFFER_CEILING_OF (start), ceiling);

        {
          /* The termination address of the dumb loop.  */ 
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          register unsigned char *ceiling_addr = POS_ADDR (ceiling) + 1;
          register unsigned char *cursor = POS_ADDR (start);
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          unsigned char *base = cursor;

          while (cursor < ceiling_addr)
            {
              unsigned char *scan_start = cursor;

              /* The dumb loop.  */
              while (*cursor != target && ++cursor < ceiling_addr)
                ;

              /* If we're looking for newlines, cache the fact that
                 the region from start to cursor is free of them. */
              if (target == '\n' && newline_cache)
                know_region_cache (current_buffer, newline_cache,
                                   start + scan_start - base,
                                   start + cursor - base);

              /* Did we find the target character?  */
              if (cursor < ceiling_addr)
                {
                  if (--count == 0)
                    {
                      immediate_quit = 0;
                      return (start + cursor - base + 1);
                    }
                  cursor++;
                }
            }

          start += cursor - base;
        }
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      }
  else
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    while (start > end)
      {
        /* The last character to check before the next obstacle.  */
        register int ceiling = end;

        /* Consult the newline cache, if appropriate.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_backward
                   (current_buffer, newline_cache, start, &next_change))
              start = next_change;
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            immediate_quit = allow_quit;
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            /* Start should never be at or before end.  */
            if (start <= end)
              start = end + 1;

            /* Now the text before start is an unknown region, and
               next_change is the position of the next known region. */
            ceiling = max (next_change, ceiling);
          }

        /* Stop scanning before the gap.  */
        ceiling = max (BUFFER_FLOOR_OF (start - 1), ceiling);

        {
          /* The termination address of the dumb loop.  */
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          register unsigned char *ceiling_addr = POS_ADDR (ceiling);
          register unsigned char *cursor = POS_ADDR (start - 1);
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          unsigned char *base = cursor;

          while (cursor >= ceiling_addr)
            {
              unsigned char *scan_start = cursor;

              while (*cursor != target && --cursor >= ceiling_addr)
                ;

              /* If we're looking for newlines, cache the fact that
                 the region from after the cursor to start is free of them.  */
              if (target == '\n' && newline_cache)
                know_region_cache (current_buffer, newline_cache,
                                   start + cursor - base,
                                   start + scan_start - base);

              /* Did we find the target character?  */
              if (cursor >= ceiling_addr)
                {
                  if (++count >= 0)
                    {
                      immediate_quit = 0;
                      return (start + cursor - base);
                    }
                  cursor--;
                }
            }

          start += cursor - base;
        }
      }

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  immediate_quit = 0;
  if (shortage != 0)
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    *shortage = count * direction;
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  return start;
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}

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int
find_next_newline_no_quit (from, cnt)
     register int from, cnt;
{
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  return scan_buffer ('\n', from, 0, cnt, (int *) 0, 0);
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}

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int
find_next_newline (from, cnt)
     register int from, cnt;
{
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  return scan_buffer ('\n', from, 0, cnt, (int *) 0, 1);
}


/* Like find_next_newline, but returns position before the newline,
   not after, and only search up to TO.  This isn't just
   find_next_newline (...)-1, because you might hit TO.  */
int
find_before_next_newline (from, to, cnt)
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     int from, to, cnt;
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{
  int shortage;
  int pos = scan_buffer ('\n', from, to, cnt, &shortage, 1);

  if (shortage == 0)
    pos--;
  
  return pos;
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}

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Lisp_Object skip_chars ();

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DEFUN ("skip-chars-forward", Fskip_chars_forward, Sskip_chars_forward, 1, 2, 0,
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  "Move point forward, stopping before a char not in STRING, or at pos LIM.\n\
STRING is like the inside of a `[...]' in a regular expression\n\
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except that `]' is never special and `\\' quotes `^', `-' or `\\'.\n\
Thus, with arg \"a-zA-Z\", this skips letters stopping before first nonletter.\n\
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With arg \"^a-zA-Z\", skips nonletters stopping before first letter.\n\
Returns the distance traveled, either zero or positive.")
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  (string, lim)
     Lisp_Object string, lim;
{
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  return skip_chars (1, 0, string, lim);
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}

DEFUN ("skip-chars-backward", Fskip_chars_backward, Sskip_chars_backward, 1, 2, 0,
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  "Move point backward, stopping after a char not in STRING, or at pos LIM.\n\
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See `skip-chars-forward' for details.\n\
Returns the distance traveled, either zero or negative.")
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  (string, lim)
     Lisp_Object string, lim;
{
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  return skip_chars (0, 0, string, lim);
}

DEFUN ("skip-syntax-forward", Fskip_syntax_forward, Sskip_syntax_forward, 1, 2, 0,
  "Move point forward across chars in specified syntax classes.\n\
SYNTAX is a string of syntax code characters.\n\
Stop before a char whose syntax is not in SYNTAX, or at position LIM.\n\
If SYNTAX starts with ^, skip characters whose syntax is NOT in SYNTAX.\n\
This function returns the distance traveled, either zero or positive.")
  (syntax, lim)
     Lisp_Object syntax, lim;
{
  return skip_chars (1, 1, syntax, lim);
}

DEFUN ("skip-syntax-backward", Fskip_syntax_backward, Sskip_syntax_backward, 1, 2, 0,
  "Move point backward across chars in specified syntax classes.\n\
SYNTAX is a string of syntax code characters.\n\
Stop on reaching a char whose syntax is not in SYNTAX, or at position LIM.\n\
If SYNTAX starts with ^, skip characters whose syntax is NOT in SYNTAX.\n\
This function returns the distance traveled, either zero or negative.")
  (syntax, lim)
     Lisp_Object syntax, lim;
{
  return skip_chars (0, 1, syntax, lim);
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}

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Lisp_Object
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skip_chars (forwardp, syntaxp, string, lim)
     int forwardp, syntaxp;
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     Lisp_Object string, lim;
{
  register unsigned char *p, *pend;
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  register unsigned int c;
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  register int ch;
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  unsigned char fastmap[0400];
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  /* If SYNTAXP is 0, STRING may contain multi-byte form of characters
     of which codes don't fit in FASTMAP.  In that case, we set the
     first byte of multibyte form (i.e. base leading-code) in FASTMAP
     and set the actual ranges of characters in CHAR_RANGES.  In the
     form "X-Y" of STRING, both X and Y must belong to the same
     character set because a range striding across character sets is
     meaningless.  */
  int *char_ranges
    = (int *) alloca (XSTRING (string)->size * (sizeof (int)) * 2);
  int n_char_ranges = 0;
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  int negate = 0;
  register int i;
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  int multibyte = !NILP (current_buffer->enable_multibyte_characters);
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  CHECK_STRING (string, 0);

  if (NILP (lim))
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    XSETINT (lim, forwardp ? ZV : BEGV);
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  else
    CHECK_NUMBER_COERCE_MARKER (lim, 1);

  /* In any case, don't allow scan outside bounds of buffer.  */
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  /* jla turned this off, for no known reason.
     bfox turned the ZV part on, and rms turned the
     BEGV part back on.  */
  if (XINT (lim) > ZV)
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    XSETFASTINT (lim, ZV);
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  if (XINT (lim) < BEGV)
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    XSETFASTINT (lim, BEGV);
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  p = XSTRING (string)->data;
  pend = p + XSTRING (string)->size;
  bzero (fastmap, sizeof fastmap);

  if (p != pend && *p == '^')
    {
      negate = 1; p++;
    }

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  /* Find the characters specified and set their elements of fastmap.
     If syntaxp, each character counts as itself.
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     Otherwise, handle backslashes and ranges specially.  */
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  while (p != pend)
    {
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      c = *p;
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      if (multibyte)
	{
	  ch = STRING_CHAR (p, pend - p);
	  p += BYTES_BY_CHAR_HEAD (*p);
	}
      else
	{
	  ch = c;
	  p++;
	}
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      if (syntaxp)
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	fastmap[syntax_spec_code[c]] = 1;
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      else
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	{
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	  if (c == '\\')
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	    {
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	      if (p == pend) break;
	      c = *p++;
	    }
	  if (p != pend && *p == '-')
	    {
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	      unsigned int ch2;

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	      p++;
	      if (p == pend) break;
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	      if (SINGLE_BYTE_CHAR_P (ch))
		while (c <= *p)
		  {
		    fastmap[c] = 1;
		    c++;
		  }
	      else
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		{
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		  fastmap[c] = 1; /* C is the base leading-code.  */
		  ch2 = STRING_CHAR (p, pend - p);
		  if (ch <= ch2)
		    char_ranges[n_char_ranges++] = ch,
		    char_ranges[n_char_ranges++] = ch2;
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		}
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	      p += multibyte ? BYTES_BY_CHAR_HEAD (*p) : 1;
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	    }
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	  else
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	    {
	      fastmap[c] = 1;
	      if (!SINGLE_BYTE_CHAR_P (ch))
		char_ranges[n_char_ranges++] = ch,
		char_ranges[n_char_ranges++] = ch;
	    }
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	}
    }

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  /* If ^ was the first character, complement the fastmap.  In
     addition, as all multibyte characters have possibility of
     matching, set all entries for base leading codes, which is
     harmless even if SYNTAXP is 1.  */
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  if (negate)
    for (i = 0; i < sizeof fastmap; i++)
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      {
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	if (!multibyte || !BASE_LEADING_CODE_P (i))
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	  fastmap[i] ^= 1;
	else
	  fastmap[i] = 1;
      }
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  {
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    int start_point = PT;
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    int pos = PT;
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    immediate_quit = 1;
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    if (syntaxp)
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      {
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	if (forwardp)
	  {
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	    if (multibyte)
	      while (pos < XINT (lim)
		     && fastmap[(int) SYNTAX (FETCH_CHAR (pos))])
		INC_POS (pos);
	    else
	      while (pos < XINT (lim)
		     && fastmap[(int) SYNTAX (FETCH_BYTE (pos))])
		pos++;
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	  }
	else
	  {
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	    if (multibyte)
	      while (pos > XINT (lim))
		{
		  int savepos = pos;
		  DEC_POS (pos);
		  if (!fastmap[(int) SYNTAX (FETCH_CHAR (pos))])
		    {
		      pos = savepos;
		      break;
		    }
		}
	    else
	      while (pos > XINT (lim)
		     && fastmap[(int) SYNTAX (FETCH_BYTE (pos - 1))])
		pos--;
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	  }
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      }
    else
      {
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	if (forwardp)
	  {
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	    if (multibyte)
	      while (pos < XINT (lim) && fastmap[(c = FETCH_BYTE (pos))])
		{
		  if (!BASE_LEADING_CODE_P (c))
		    pos++;
		  else if (n_char_ranges)
		    {
		      /* We much check CHAR_RANGES for a multibyte
			 character.  */
		      ch = FETCH_MULTIBYTE_CHAR (pos);
		      for (i = 0; i < n_char_ranges; i += 2)
			if ((ch >= char_ranges[i] && ch <= char_ranges[i + 1]))
			  break;
		      if (!(negate ^ (i < n_char_ranges)))
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			break;

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		      INC_POS (pos);
		    }
		  else
		    {
		      if (!negate) break;
		      INC_POS (pos);
		    }
		}
	    else
	      while (pos < XINT (lim) && fastmap[FETCH_BYTE (pos)])
		pos++;
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	  }
	else
	  {
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	    if (multibyte)
	      while (pos > XINT (lim))
		{
		  int savepos = pos;
		  DEC_POS (pos);
		  if (fastmap[(c = FETCH_BYTE (pos))])
		    {
		      if (!BASE_LEADING_CODE_P (c))
			;
		      else if (n_char_ranges)
			{
			  /* We much check CHAR_RANGES for a multibyte
			     character.  */
			  ch = FETCH_MULTIBYTE_CHAR (pos);
			  for (i = 0; i < n_char_ranges; i += 2)
			    if (ch >= char_ranges[i] && ch <= char_ranges[i + 1])
			      break;
			  if (!(negate ^ (i < n_char_ranges)))
			    {
			      pos = savepos;
			      break;
			    }
			}
		      else
			if (!negate)
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			  {
			    pos = savepos;
			    break;
			  }
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		    }
		  else
		    {
		      pos = savepos;
		      break;
		    }
		}
	    else
	      while (pos > XINT (lim) && fastmap[FETCH_BYTE (pos - 1)])
		pos--;
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	  }
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      }
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    if (multibyte
	/* INC_POS or DEC_POS might have moved POS over LIM.  */
	&& (forwardp ? (pos > XINT (lim)) : (pos < XINT (lim))))
      pos = XINT (lim);

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    SET_PT (pos);
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    immediate_quit = 0;

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    return make_number (PT - start_point);
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  }
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}

/* Subroutines of Lisp buffer search functions. */

static Lisp_Object
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search_command (string, bound, noerror, count, direction, RE, posix)
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     Lisp_Object string, bound, noerror, count;
     int direction;
     int RE;
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     int posix;
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{
  register int np;
  int lim;
  int n = direction;

  if (!NILP (count))
    {
      CHECK_NUMBER (count, 3);
      n *= XINT (count);
    }

  CHECK_STRING (string, 0);
  if (NILP (bound))
    lim = n > 0 ? ZV : BEGV;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (bound, 1);
      lim = XINT (bound);
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      if (n > 0 ? lim < PT : lim > PT)
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	error ("Invalid search bound (wrong side of point)");
      if (lim > ZV)
	lim = ZV;
      if (lim < BEGV)
	lim = BEGV;
    }

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  np = search_buffer (string, PT, lim, n, RE,
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		      (!NILP (current_buffer->case_fold_search)
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		       ? XCHAR_TABLE (current_buffer->case_canon_table)->contents
		       : 0),
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		      (!NILP (current_buffer->case_fold_search)
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		       ? XCHAR_TABLE (current_buffer->case_eqv_table)->contents
		       : 0),
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		      posix);
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  if (np <= 0)
    {
      if (NILP (noerror))
	return signal_failure (string);
      if (!EQ (noerror, Qt))
	{
	  if (lim < BEGV || lim > ZV)
	    abort ();
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	  SET_PT (lim);
	  return Qnil;
#if 0 /* This would be clean, but maybe programs depend on
	 a value of nil here.  */
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	  np = lim;
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#endif
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	}
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      else
	return Qnil;
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    }

  if (np < BEGV || np > ZV)
    abort ();

  SET_PT (np);

  return make_number (np);
}

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static int
trivial_regexp_p (regexp)
     Lisp_Object regexp;
{
  int len = XSTRING (regexp)->size;
  unsigned char *s = XSTRING (regexp)->data;
  unsigned char c;
  while (--len >= 0)
    {
      switch (*s++)
	{
	case '.': case '*': case '+': case '?': case '[': case '^': case '$':
	  return 0;
	case '\\':
	  if (--len < 0)
	    return 0;
	  switch (*s++)
	    {
	    case '|': case '(': case ')': case '`': case '\'': case 'b':
	    case 'B': case '<': case '>': case 'w': case 'W': case 's':
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	    case 'S': case '=':
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	    case 'c': case 'C':	/* for categoryspec and notcategoryspec */
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	    case '1': case '2': case '3': case '4': case '5':
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	    case '6': case '7': case '8': case '9':
	      return 0;
	    }
	}
    }
  return 1;
}

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/* Search for the n'th occurrence of STRING in the current buffer,
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   starting at position POS and stopping at position LIM,
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   treating STRING as a literal string if RE is false or as
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   a regular expression if RE is true.

   If N is positive, searching is forward and LIM must be greater than POS.
   If N is negative, searching is backward and LIM must be less than POS.

   Returns -x if only N-x occurrences found (x > 0),
   or else the position at the beginning of the Nth occurrence
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   (if searching backward) or the end (if searching forward).

   POSIX is nonzero if we want full backtracking (POSIX style)
   for this pattern.  0 means backtrack only enough to get a valid match.  */
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static int
search_buffer (string, pos, lim, n, RE, trt, inverse_trt, posix)
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     Lisp_Object string;
     int pos;
     int lim;
     int n;
     int RE;
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     Lisp_Object *trt;
     Lisp_Object *inverse_trt;
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     int posix;
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{
  int len = XSTRING (string)->size;
  unsigned char *base_pat = XSTRING (string)->data;
  register int *BM_tab;
  int *BM_tab_base;
  register int direction = ((n > 0) ? 1 : -1);
  register int dirlen;
  int infinity, limit, k, stride_for_teases;
  register unsigned char *pat, *cursor, *p_limit;  
  register int i, j;
  unsigned char *p1, *p2;
  int s1, s2;

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  if (running_asynch_code)
    save_search_regs ();

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  /* Null string is found at starting position.  */
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  if (len == 0)
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    {
      set_search_regs (pos, 0);
      return pos;
    }
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  /* Searching 0 times means don't move.  */
  if (n == 0)
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    return pos;

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  if (RE && !trivial_regexp_p (string))
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    {
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      struct re_pattern_buffer *bufp;

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      bufp = compile_pattern (string, &search_regs, trt, posix);
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      immediate_quit = 1;	/* Quit immediately if user types ^G,
				   because letting this function finish
				   can take too long. */
      QUIT;			/* Do a pending quit right away,
				   to avoid paradoxical behavior */
      /* Get pointers and sizes of the two strings
	 that make up the visible portion of the buffer. */

      p1 = BEGV_ADDR;
      s1 = GPT - BEGV;
      p2 = GAP_END_ADDR;
      s2 = ZV - GPT;
      if (s1 < 0)
	{
	  p2 = p1;
	  s2 = ZV - BEGV;
	  s1 = 0;
	}
      if (s2 < 0)
	{
	  s1 = ZV - BEGV;
	  s2 = 0;
	}
      while (n < 0)
	{
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	  int val;
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	  val = re_search_2 (bufp, (char *) p1, s1, (char *) p2, s2,
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			     pos - BEGV, lim - pos, &search_regs,
			     /* Don't allow match past current point */
			     pos - BEGV);
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	  if (val == -2)
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	    {
	      matcher_overflow ();
	    }
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	  if (val >= 0)
	    {
	      j = BEGV;
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	      for (i = 0; i < search_regs.num_regs; i++)
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		if (search_regs.start[i] >= 0)
		  {
		    search_regs.start[i] += j;
		    search_regs.end[i] += j;
		  }
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	      XSETBUFFER (last_thing_searched, current_buffer);
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	      /* Set pos to the new position. */
	      pos = search_regs.start[0];
	    }
	  else
	    {
	      immediate_quit = 0;
	      return (n);
	    }
	  n++;
	}
      while (n > 0)
	{
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	  int val;
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	  val = re_search_2 (bufp, (char *) p1, s1, (char *) p2, s2,
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			     pos - BEGV, lim - pos, &search_regs,
			     lim - BEGV);
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	  if (val == -2)
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	    {
	      matcher_overflow ();
	    }
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	  if (val >= 0)
	    {
	      j = BEGV;
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	      for (i = 0; i < search_regs.num_regs; i++)
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		if (search_regs.start[i] >= 0)
		  {
		    search_regs.start[i] += j;
		    search_regs.end[i] += j;
		  }
1198 </