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search.c

/* String search routines for XEmacs.
   Copyright (C) 1985, 1986, 1987, 1992-1995 Free Software Foundation, Inc.
   Copyright (C) 1995 Sun Microsystems, Inc.

This file is part of XEmacs.

XEmacs 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.

XEmacs 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 XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Synched up with: FSF 19.29, except for region-cache stuff. */

/* Hacked on for Mule by Ben Wing, December 1994 and August 1995. */

/* This file has been Mule-ized except for the TRT stuff. */

#include <config.h>
#include "lisp.h"

#include "buffer.h"
#include "insdel.h"
#include "opaque.h"
#ifdef REGION_CACHE_NEEDS_WORK
#include "region-cache.h"
#endif
#include "syntax.h"

#include <sys/types.h>
#include "regex.h"
#include "casetab.h"
#include "chartab.h"

#define TRANSLATE(table, pos) \
 (!NILP (table) ? TRT_TABLE_OF (table, (Emchar) pos) : pos)

#define REGEXP_CACHE_SIZE 20

/* If the regexp is non-nil, then the buffer contains the compiled form
   of that regexp, suitable for searching.  */
struct regexp_cache
{
  struct regexp_cache *next;
  Lisp_Object regexp;
  struct re_pattern_buffer buf;
  char fastmap[0400];
  /* Nonzero means regexp was compiled to do full POSIX backtracking.  */
  char posix;
};

/* The instances of that struct.  */
static struct regexp_cache searchbufs[REGEXP_CACHE_SIZE];

/* The head of the linked list; points to the most recently used buffer.  */
static struct regexp_cache *searchbuf_head;


/* 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
   been allocated by checking search_regs.num_regs.

   The regex code keeps track of whether it has allocated the search
   buffer using bits in the re_pattern_buffer.  This means that whenever
   you compile a new pattern, it completely forgets whether it has
   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.  */

/* Note: things get trickier under Mule because the values returned from
   the regexp routines are in Bytinds but we need them to be in Bufpos's.
   We take the easy way out for the moment and just convert them immediately.
   We could be more clever by not converting them until necessary, but
   that gets real ugly real fast since the buffer might have changed and
   the positions might be out of sync or out of range.
   */
static struct re_registers search_regs;

/* 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;

/* error condition signalled when regexp compile_pattern fails */

Lisp_Object Qinvalid_regexp;

/* Regular expressions used in forward/backward-word */
Lisp_Object Vforward_word_regexp, Vbackward_word_regexp;

/* range table for use with skip_chars.  Only needed for Mule. */
Lisp_Object Vskip_chars_range_table;

static void set_search_regs (struct buffer *buf, Bufpos beg, Charcount len);
static void clear_unused_search_regs (struct re_registers *regp, int no_sub);
static void save_search_regs (void);
static Bufpos simple_search (struct buffer *buf, Bufbyte *base_pat,
                       Bytecount len, Bytind pos, Bytind lim,
                       EMACS_INT n, Lisp_Object trt);
static Bufpos boyer_moore (struct buffer *buf, Bufbyte *base_pat,
                     Bytecount len, Bytind pos, Bytind lim,
                     EMACS_INT n, Lisp_Object trt,
                     Lisp_Object inverse_trt, int charset_base);
static Bufpos search_buffer (struct buffer *buf, Lisp_Object str,
                       Bufpos bufpos, Bufpos buflim, EMACS_INT n, int RE,
                       Lisp_Object trt, Lisp_Object inverse_trt,
                       int posix);

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

/* 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)
   for this pattern.  0 means backtrack only enough to get a valid match.  */

static int
compile_pattern_1 (struct regexp_cache *cp, Lisp_Object pattern,
               Lisp_Object translate, struct re_registers *regp, int posix,
               Error_behavior errb)
{
  const char *val;
  reg_syntax_t old;

  cp->regexp = Qnil;
  cp->buf.translate = translate;
  cp->posix = posix;
  old = re_set_syntax (RE_SYNTAX_EMACS
                   | (posix ? 0 : RE_NO_POSIX_BACKTRACKING));
  val = (const char *)
    re_compile_pattern ((char *) XSTRING_DATA (pattern),
                  XSTRING_LENGTH (pattern), &cp->buf);
  re_set_syntax (old);
  if (val)
    {
      maybe_signal_error (Qinvalid_regexp, list1 (build_string (val)),
                    Qsearch, errb);
      return 0;
    }

  cp->regexp = Fcopy_sequence (pattern);
  return 1;
}

/* Compile a regexp if necessary, but first check to see if there's one in
   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.  */

struct re_pattern_buffer *
compile_pattern (Lisp_Object pattern, struct re_registers *regp,
             Lisp_Object translate, int posix, Error_behavior errb)
{
  struct regexp_cache *cp, **cpp;

  for (cpp = &searchbuf_head; ; cpp = &cp->next)
    {
      cp = *cpp;
      if (!NILP (Fstring_equal (cp->regexp, pattern))
        && EQ (cp->buf.translate, translate)
        && cp->posix == posix)
      break;

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

  /* 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);

  return &cp->buf;
}

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

static Lisp_Object
signal_failure (Lisp_Object arg)
{
  for (;;)
    Fsignal (Qsearch_failed, list1 (arg));
  return Qnil; /* Not reached. */
}

/* Convert the search registers from Bytinds to Bufpos's.  Needs to be
   done after each regexp match that uses the search regs.

   We could get a potential speedup by not converting the search registers
   until it's really necessary, e.g. when match-data or replace-match is
   called.  However, this complexifies the code a lot (e.g. the buffer
   could have changed and the Bytinds stored might be invalid) and is
   probably not a great time-saver. */

static void
fixup_search_regs_for_buffer (struct buffer *buf)
{
  int i;
  int num_regs = search_regs.num_regs;

  for (i = 0; i < num_regs; i++)
    {
      if (search_regs.start[i] >= 0)
      search_regs.start[i] = bytind_to_bufpos (buf, search_regs.start[i]);
      if (search_regs.end[i] >= 0)
      search_regs.end[i] = bytind_to_bufpos (buf, search_regs.end[i]);
    }
}

/* Similar but for strings. */
static void
fixup_search_regs_for_string (Lisp_Object string)
{
  int i;
  int num_regs = search_regs.num_regs;

  /* #### bytecount_to_charcount() is not that efficient.  This function
     could be faster if it did its own conversion (using INC_CHARPTR()
     and such), because the register ends are likely to be somewhat ordered.
     (Even if not, you could sort them.)

     Think about this if this function is a time hog, which it's probably
     not. */
  for (i = 0; i < num_regs; i++)
    {
      if (search_regs.start[i] > 0)
      {
        search_regs.start[i] =
          bytecount_to_charcount (XSTRING_DATA (string),
                            search_regs.start[i]);
      }
      if (search_regs.end[i] > 0)
      {
        search_regs.end[i] =
          bytecount_to_charcount (XSTRING_DATA (string),
                            search_regs.end[i]);
      }
    }
}


static Lisp_Object
looking_at_1 (Lisp_Object string, struct buffer *buf, int posix)
{
  /* This function has been Mule-ized, except for the trt table handling. */
  Lisp_Object val;
  Bytind p1, p2;
  Bytecount s1, s2;
  REGISTER int i;
  struct re_pattern_buffer *bufp;

  if (running_asynch_code)
    save_search_regs ();

  CHECK_STRING (string);
  bufp = compile_pattern (string, &search_regs,
                    (!NILP (buf->case_fold_search)
                     ? XCASE_TABLE_DOWNCASE (buf->case_table) : Qnil),
                    posix, ERROR_ME);

  QUIT;

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

  p1 = BI_BUF_BEGV (buf);
  p2 = BI_BUF_CEILING_OF (buf, p1);
  s1 = p2 - p1;
  s2 = BI_BUF_ZV (buf) - p2;

  regex_match_object = Qnil;
  regex_emacs_buffer = buf;
  i = re_match_2 (bufp, (char *) BI_BUF_BYTE_ADDRESS (buf, p1),
              s1, (char *) BI_BUF_BYTE_ADDRESS (buf, p2), s2,
              BI_BUF_PT (buf) - BI_BUF_BEGV (buf), &search_regs,
              BI_BUF_ZV (buf) - BI_BUF_BEGV (buf));

  if (i == -2)
    matcher_overflow ();

  val = (0 <= i ? Qt : Qnil);
  if (NILP (val))
    return Qnil;
  {
    int num_regs = search_regs.num_regs;
    for (i = 0; i < num_regs; i++)
      if (search_regs.start[i] >= 0)
      {
        search_regs.start[i] += BI_BUF_BEGV (buf);
        search_regs.end[i] += BI_BUF_BEGV (buf);
      }
  }
  XSETBUFFER (last_thing_searched, buf);
  fixup_search_regs_for_buffer (buf);
  return val;
}

DEFUN ("looking-at", Flooking_at, 1, 2, 0, /*
Return t if text after point matches regular expression REGEXP.
This function modifies the match data that `match-beginning',
`match-end' and `match-data' access; save and restore the match
data if you want to preserve them.

Optional argument BUFFER defaults to the current buffer.
*/
       (regexp, buffer))
{
  return looking_at_1 (regexp, decode_buffer (buffer, 0), 0);
}

DEFUN ("posix-looking-at", Fposix_looking_at, 1, 2, 0, /*
Return t if text after point matches regular expression REGEXP.
Find the longest match, in accord with Posix regular expression rules.
This function modifies the match data that `match-beginning',
`match-end' and `match-data' access; save and restore the match
data if you want to preserve them.

Optional argument BUFFER defaults to the current buffer.
*/
       (regexp, buffer))
{
  return looking_at_1 (regexp,  decode_buffer (buffer, 0), 1);
}

static Lisp_Object
string_match_1 (Lisp_Object regexp, Lisp_Object string, Lisp_Object start,
            struct buffer *buf, int posix)
{
  /* This function has been Mule-ized, except for the trt table handling. */
  Bytecount val;
  Charcount s;
  struct re_pattern_buffer *bufp;

  if (running_asynch_code)
    save_search_regs ();

  CHECK_STRING (regexp);
  CHECK_STRING (string);

  if (NILP (start))
    s = 0;
  else
    {
      Charcount len = XSTRING_CHAR_LENGTH (string);

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


  bufp = compile_pattern (regexp, &search_regs,
                    (!NILP (buf->case_fold_search)
                     ? XCASE_TABLE_DOWNCASE (buf->case_table) : Qnil),
                    0, ERROR_ME);
  QUIT;
  {
    Bytecount bis = charcount_to_bytecount (XSTRING_DATA (string), s);
    regex_match_object = string;
    regex_emacs_buffer = buf;
    val = re_search (bufp, (char *) XSTRING_DATA (string),
                 XSTRING_LENGTH (string), bis,
                 XSTRING_LENGTH (string) - bis,
                 &search_regs);
  }
  if (val == -2)
    matcher_overflow ();
  if (val < 0) return Qnil;
  last_thing_searched = Qt;
  fixup_search_regs_for_string (string);
  return make_int (bytecount_to_charcount (XSTRING_DATA (string), val));
}

DEFUN ("string-match", Fstring_match, 2, 4, 0, /*
Return index of start of first match for REGEXP in STRING, or nil.
If third arg START is non-nil, start search at that index in STRING.
For index of first char beyond the match, do (match-end 0).
`match-end' and `match-beginning' also give indices of substrings
matched by parenthesis constructs in the pattern.

Optional arg BUFFER controls how case folding is done (according to
the value of `case-fold-search' in that buffer and that buffer's case
tables) and defaults to the current buffer.
*/
       (regexp, string, start, buffer))
{
  return string_match_1 (regexp, string, start, decode_buffer (buffer, 0), 0);
}

DEFUN ("posix-string-match", Fposix_string_match, 2, 4, 0, /*
Return index of start of first match for REGEXP in STRING, or nil.
Find the longest match, in accord with Posix regular expression rules.
If third arg START is non-nil, start search at that index in STRING.
For index of first char beyond the match, do (match-end 0).
`match-end' and `match-beginning' also give indices of substrings
matched by parenthesis constructs in the pattern.

Optional arg BUFFER controls how case folding is done (according to
the value of `case-fold-search' in that buffer and that buffer's case
tables) and defaults to the current buffer.
*/
       (regexp, string, start, buffer))
{
  return string_match_1 (regexp, string, start, decode_buffer (buffer, 0), 1);
}

/* 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. */

Bytecount
fast_string_match (Lisp_Object regexp,  const Bufbyte *nonreloc,
               Lisp_Object reloc, Bytecount offset,
               Bytecount length, int case_fold_search,
               Error_behavior errb, int no_quit)
{
  /* This function has been Mule-ized, except for the trt table handling. */
  Bytecount val;
  Bufbyte *newnonreloc = (Bufbyte *) nonreloc;
  struct re_pattern_buffer *bufp;

  bufp = compile_pattern (regexp, 0,
                    (case_fold_search
                     ? XCASE_TABLE_DOWNCASE (current_buffer->case_table)
                     : Qnil),
                    0, errb);
  if (!bufp)
    return -1; /* will only do this when errb != ERROR_ME */
  if (!no_quit)
    QUIT;
  else
    no_quit_in_re_search = 1;

  fixup_internal_substring (nonreloc, reloc, offset, &length);

  if (!NILP (reloc))
    {
      if (no_quit)
      newnonreloc = XSTRING_DATA (reloc);
      else
      {
        /* QUIT could relocate RELOC.  Therefore we must alloca()
           and copy.  No way around this except some serious
           rewriting of re_search(). */
        newnonreloc = (Bufbyte *) alloca (length);
        memcpy (newnonreloc, XSTRING_DATA (reloc), length);
      }
    }

  /* #### evil current-buffer dependency */
  regex_match_object = reloc;
  regex_emacs_buffer = current_buffer;
  val = re_search (bufp, (char *) newnonreloc + offset, length, 0,
               length, 0);

  no_quit_in_re_search = 0;
  return val;
}

Bytecount
fast_lisp_string_match (Lisp_Object regex, Lisp_Object string)
{
  return fast_string_match (regex, 0, string, 0, -1, 0, ERROR_ME, 0);
}


#ifdef REGION_CACHE_NEEDS_WORK
/* 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 (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 ();
    }
}
#endif

/* Search in BUF 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.

   If we find COUNT instances, set *SHORTAGE to zero, and return the
   position after the COUNTth match.  Note that for reverse motion
   this is not the same as the usual convention for Emacs motion commands.

   If we don't find COUNT instances before reaching END, set *SHORTAGE
   to the number of TARGETs left unfound, and return END.

   If ALLOW_QUIT is non-zero, call QUIT periodically. */

static Bytind
bi_scan_buffer (struct buffer *buf, Emchar target, Bytind st, Bytind en,
            EMACS_INT count, EMACS_INT *shortage, int allow_quit)
{
  /* This function has been Mule-ized. */
  Bytind lim = en > 0 ? en :
    ((count > 0) ? BI_BUF_ZV (buf) : BI_BUF_BEGV (buf));

  /* #### newline cache stuff in this function not yet ported */

  assert (count != 0);

  if (shortage)
    *shortage = 0;

  if (count > 0)
    {
#ifdef MULE
      /* Due to the Mule representation of characters in a buffer,
       we can simply search for characters in the range 0 - 127
       directly.  For other characters, we do it the "hard" way.
       Note that this way works for all characters but the other
       way is faster. */
      if (target >= 0200)
      {
        while (st < lim && count > 0)
          {
            if (BI_BUF_FETCH_CHAR (buf, st) == target)
            count--;
            INC_BYTIND (buf, st);
          }
      }
      else
#endif
      {
        while (st < lim && count > 0)
          {
            Bytind ceil;
            Bufbyte *bufptr;

            ceil = BI_BUF_CEILING_OF (buf, st);
            ceil = min (lim, ceil);
            bufptr = (Bufbyte *) memchr (BI_BUF_BYTE_ADDRESS (buf, st),
                                 (int) target, ceil - st);
            if (bufptr)
            {
              count--;
              st = BI_BUF_PTR_BYTE_POS (buf, bufptr) + 1;
            }
            else
            st = ceil;
          }
      }

      if (shortage)
      *shortage = count;
      if (allow_quit)
      QUIT;
      return st;
    }
  else
    {
#ifdef MULE
      if (target >= 0200)
      {
        while (st > lim && count < 0)
          {
            DEC_BYTIND (buf, st);
            if (BI_BUF_FETCH_CHAR (buf, st) == target)
            count++;
          }
      }
      else
#endif
      {
        while (st > lim && count < 0)
          {
            Bytind floor;
            Bufbyte *bufptr;
            Bufbyte *floorptr;

            floor = BI_BUF_FLOOR_OF (buf, st);
            floor = max (lim, floor);
            /* No memrchr() ... */
            bufptr = BI_BUF_BYTE_ADDRESS_BEFORE (buf, st);
            floorptr = BI_BUF_BYTE_ADDRESS (buf, floor);
            while (bufptr >= floorptr)
            {
              st--;
              /* At this point, both ST and BUFPTR refer to the same
                 character.  When the loop terminates, ST will
                 always point to the last character we tried. */
              if (* (unsigned char *) bufptr == (unsigned char) target)
                {
                  count++;
                  break;
                }
              bufptr--;
            }
          }
      }

      if (shortage)
      *shortage = -count;
      if (allow_quit)
      QUIT;
      if (count)
      return st;
      else
      {
      /* We found the character we were looking for; we have to return
         the position *after* it due to the strange way that the return
         value is defined. */
        INC_BYTIND (buf, st);
        return st;
      }
    }
}

Bufpos
scan_buffer (struct buffer *buf, Emchar target, Bufpos start, Bufpos end,
           EMACS_INT count, EMACS_INT *shortage, int allow_quit)
{
  Bytind bi_retval;
  Bytind bi_start, bi_end;

  bi_start = bufpos_to_bytind (buf, start);
  if (end)
    bi_end = bufpos_to_bytind (buf, end);
  else
    bi_end = 0;
  bi_retval = bi_scan_buffer (buf, target, bi_start, bi_end, count,
                        shortage, allow_quit);
  return bytind_to_bufpos (buf, bi_retval);
}

Bytind
bi_find_next_newline_no_quit (struct buffer *buf, Bytind from, int count)
{
  return bi_scan_buffer (buf, '\n', from, 0, count, 0, 0);
}

Bufpos
find_next_newline_no_quit (struct buffer *buf, Bufpos from, int count)
{
  return scan_buffer (buf, '\n', from, 0, count, 0, 0);
}

Bufpos
find_next_newline (struct buffer *buf, Bufpos from, int count)
{
  return scan_buffer (buf, '\n', from, 0, count, 0, 1);
}

Bytind
bi_find_next_emchar_in_string (Lisp_String* str, Emchar target, Bytind st,
                         EMACS_INT count)
{
  /* This function has been Mule-ized. */
  Bytind lim = string_length (str) -1;
  Bufbyte* s = string_data (str);

  assert (count >= 0);

#ifdef MULE
  /* Due to the Mule representation of characters in a buffer,
     we can simply search for characters in the range 0 - 127
     directly.  For other characters, we do it the "hard" way.
     Note that this way works for all characters but the other
     way is faster. */
  if (target >= 0200)
    {
      while (st < lim && count > 0)
      {
        if (string_char (str, st) == target)
          count--;
        INC_CHARBYTIND (s, st);
      }
    }
  else
#endif
    {
      while (st < lim && count > 0)
      {
        Bufbyte *bufptr = (Bufbyte *) memchr (charptr_n_addr (s, st),
                                    (int) target, lim - st);
        if (bufptr)
          {
            count--;
            st =  (Bytind)(bufptr - s) + 1;
          }
        else
          st = lim;
      }
    }
  return st;
}

/* 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.  */
Bufpos
find_before_next_newline (struct buffer *buf, Bufpos from, Bufpos to, int count)
{
  EMACS_INT shortage;
  Bufpos pos = scan_buffer (buf, '\n', from, to, count, &shortage, 1);

  if (shortage == 0)
    pos--;

  return pos;
}

/* This function synched with FSF 21.1 */
static Lisp_Object
skip_chars (struct buffer *buf, int forwardp, int syntaxp,
          Lisp_Object string, Lisp_Object lim)
{
  /* This function has been Mule-ized. */
  REGISTER Bufbyte *p, *pend;
  REGISTER Emchar c;
  /* We store the first 256 chars in an array here and the rest in
     a range table. */
  unsigned char fastmap[0400];
  int negate = 0;
  REGISTER int i;
#ifndef emacs
  Lisp_Char_Table *syntax_table = XCHAR_TABLE (buf->mirror_syntax_table);
#endif
  Bufpos limit;

  if (NILP (lim))
    limit = forwardp ? BUF_ZV (buf) : BUF_BEGV (buf);
  else
    {
      CHECK_INT_COERCE_MARKER (lim);
      limit = XINT (lim);

      /* In any case, don't allow scan outside bounds of buffer.  */
      if (limit > BUF_ZV   (buf)) limit = BUF_ZV   (buf);
      if (limit < BUF_BEGV (buf)) limit = BUF_BEGV (buf);
    }

  CHECK_STRING (string);
  p = XSTRING_DATA (string);
  pend = p + XSTRING_LENGTH (string);
  memset (fastmap, 0, sizeof (fastmap));

  Fclear_range_table (Vskip_chars_range_table);

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

  /* Find the characters specified and set their elements of fastmap.
     If syntaxp, each character counts as itself.
     Otherwise, handle backslashes and ranges specially  */

  while (p != pend)
    {
      c = charptr_emchar (p);
      INC_CHARPTR (p);
      if (syntaxp)
      {
        if (c < 0400 && syntax_spec_code[c] < (unsigned char) Smax)
          fastmap[c] = 1;
        else
          signal_simple_error ("Invalid syntax designator",
                         make_char (c));
      }
      else
      {
        if (c == '\\')
          {
            if (p == pend) break;
            c = charptr_emchar (p);
            INC_CHARPTR (p);
          }
        if (p != pend && *p == '-')
          {
            Emchar cend;

            /* Skip over the dash.  */
            p++;
            if (p == pend) break;
            cend = charptr_emchar (p);
            while (c <= cend && c < 0400)
            {
              fastmap[c] = 1;
              c++;
            }
            if (c <= cend)
            Fput_range_table (make_int (c), make_int (cend), Qt,
                          Vskip_chars_range_table);
            INC_CHARPTR (p);
          }
        else
          {
            if (c < 0400)
            fastmap[c] = 1;
            else
            Fput_range_table (make_int (c), make_int (c), Qt,
                          Vskip_chars_range_table);
          }
      }
    }

  /* #### Not in FSF 21.1 */
  if (syntaxp && fastmap['-'] != 0)
    fastmap[' '] = 1;

  /* If ^ was the first character, complement the fastmap.
     We don't complement the range table, however; we just use negate
     in the comparisons below. */

  if (negate)
    for (i = 0; i < (int) (sizeof fastmap); i++)
      fastmap[i] ^= 1;

  {
    Bufpos start_point = BUF_PT (buf);
    Bufpos pos = start_point;
    Bytind pos_byte = BI_BUF_PT (buf);

    if (syntaxp)
      {
      SETUP_SYNTAX_CACHE_FOR_BUFFER (buf, pos, forwardp ? 1 : -1);
      /* All syntax designators are normal chars so nothing strange
         to worry about */
      if (forwardp)
        {
          if (pos < limit)
            while (fastmap[(unsigned char)
                       syntax_code_spec
                       [(int) SYNTAX_FROM_CACHE
                        (syntax_table,
                         BI_BUF_FETCH_CHAR (buf, pos_byte))]])
            {
              pos++;
              INC_BYTIND (buf, pos_byte);
              if (pos >= limit)
                break;
              UPDATE_SYNTAX_CACHE_FORWARD (pos);
            }
        }
      else
        {
          while (pos > limit)
            {
            Bufpos savepos = pos_byte;
            pos--;
            DEC_BYTIND (buf, pos_byte);
            UPDATE_SYNTAX_CACHE_BACKWARD (pos);
            if (!fastmap[(unsigned char)
                       syntax_code_spec
                       [(int) SYNTAX_FROM_CACHE
                        (syntax_table,
                         BI_BUF_FETCH_CHAR (buf, pos_byte))]])
              {
                pos++;
                pos_byte = savepos;
                break;
              }
            }
        }
      }
    else
      {
      if (forwardp)
        {
          while (pos < limit)
            {
            Emchar ch = BI_BUF_FETCH_CHAR (buf, pos_byte);
            if ((ch < 0400) ? fastmap[ch] :
                (NILP (Fget_range_table (make_int (ch),
                                   Vskip_chars_range_table,
                                   Qnil))
                 == negate))
              {
                pos++;
                INC_BYTIND (buf, pos_byte);
              }
            else
              break;
            }
        }
      else
        {
          while (pos > limit)
            {
            Bufpos prev_pos_byte = pos_byte;
            Emchar ch;

            DEC_BYTIND (buf, prev_pos_byte);
            ch = BI_BUF_FETCH_CHAR (buf, prev_pos_byte);
            if ((ch < 0400) ? fastmap[ch] :
                  (NILP (Fget_range_table (make_int (ch),
                                     Vskip_chars_range_table,
                                     Qnil))
                   == negate))
              {
                pos--;
                pos_byte = prev_pos_byte;
              }
            else
              break;
            }
        }
      }
    QUIT;
    BOTH_BUF_SET_PT (buf, pos, pos_byte);
    return make_int (BUF_PT (buf) - start_point);
  }
}

DEFUN ("skip-chars-forward", Fskip_chars_forward, 1, 3, 0, /*
Move point forward, stopping before a char not in STRING, or at pos LIMIT.
STRING is like the inside of a `[...]' in a regular expression
except that `]' is never special and `\\' quotes `^', `-' or `\\'.
Thus, with arg "a-zA-Z", this skips letters stopping before first nonletter.
With arg "^a-zA-Z", skips nonletters stopping before first letter.
Returns the distance traveled, either zero or positive.

Optional argument BUFFER defaults to the current buffer.
*/
       (string, limit, buffer))
{
  return skip_chars (decode_buffer (buffer, 0), 1, 0, string, limit);
}

DEFUN ("skip-chars-backward", Fskip_chars_backward, 1, 3, 0, /*
Move point backward, stopping after a char not in STRING, or at pos LIMIT.
See `skip-chars-forward' for details.
Returns the distance traveled, either zero or negative.

Optional argument BUFFER defaults to the current buffer.
*/
       (string, limit, buffer))
{
  return skip_chars (decode_buffer (buffer, 0), 0, 0, string, limit);
}


DEFUN ("skip-syntax-forward", Fskip_syntax_forward, 1, 3, 0, /*
Move point forward across chars in specified syntax classes.
SYNTAX is a string of syntax code characters.
Stop before a char whose syntax is not in SYNTAX, or at position LIMIT.
If SYNTAX starts with ^, skip characters whose syntax is NOT in SYNTAX.
This function returns the distance traveled, either zero or positive.

Optional argument BUFFER defaults to the current buffer.
*/
       (syntax, limit, buffer))
{
  return skip_chars (decode_buffer (buffer, 0), 1, 1, syntax, limit);
}

DEFUN ("skip-syntax-backward", Fskip_syntax_backward, 1, 3, 0, /*
Move point backward across chars in specified syntax classes.
SYNTAX is a string of syntax code characters.
Stop on reaching a char whose syntax is not in SYNTAX, or at position LIMIT.
If SYNTAX starts with ^, skip characters whose syntax is NOT in SYNTAX.
This function returns the distance traveled, either zero or negative.

Optional argument BUFFER defaults to the current buffer.
*/
       (syntax, limit, buffer))
{
  return skip_chars (decode_buffer (buffer, 0), 0, 1, syntax, limit);
}


/* Subroutines of Lisp buffer search functions. */

static Lisp_Object
search_command (Lisp_Object string, Lisp_Object limit, Lisp_Object noerror,
            Lisp_Object count, Lisp_Object buffer, int direction,
            int RE, int posix)
{
  /* This function has been Mule-ized, except for the trt table handling. */
  REGISTER Bufpos np;
  Bufpos lim;
  EMACS_INT n = direction;
  struct buffer *buf;

  if (!NILP (count))
    {
      CHECK_INT (count);
      n *= XINT (count);
    }

  buf = decode_buffer (buffer, 0);
  CHECK_STRING (string);
  if (NILP (limit))
    lim = n > 0 ? BUF_ZV (buf) : BUF_BEGV (buf);
  else
    {
      CHECK_INT_COERCE_MARKER (limit);
      lim = XINT (limit);
      if (n > 0 ? lim < BUF_PT (buf) : lim > BUF_PT (buf))
      error ("Invalid search limit (wrong side of point)");
      if (lim > BUF_ZV (buf))
      lim = BUF_ZV (buf);
      if (lim < BUF_BEGV (buf))
      lim = BUF_BEGV (buf);
    }

  np = search_buffer (buf, string, BUF_PT (buf), lim, n, RE,
                  (!NILP (buf->case_fold_search)
                   ? XCASE_TABLE_CANON (buf->case_table)
                       : Qnil),
                  (!NILP (buf->case_fold_search)
                   ? XCASE_TABLE_EQV (buf->case_table)
                       : Qnil), posix);

  if (np <= 0)
    {
      if (NILP (noerror))
      return signal_failure (string);
      if (!EQ (noerror, Qt))
      {
        if (lim < BUF_BEGV (buf) || lim > BUF_ZV (buf))
          ABORT ();
        BUF_SET_PT (buf, lim);
        return Qnil;
#if 0 /* This would be clean, but maybe programs depend on
       a value of nil here.  */
        np = lim;
#endif
      }
      else
        return Qnil;
    }

  if (np < BUF_BEGV (buf) || np > BUF_ZV (buf))
    ABORT ();

  BUF_SET_PT (buf, np);

  return make_int (np);
}

static int
trivial_regexp_p (Lisp_Object regexp)
{
  /* This function has been Mule-ized. */
  Bytecount len = XSTRING_LENGTH (regexp);
  Bufbyte *s = XSTRING_DATA (regexp);
  while (--len >= 0)
    {
      switch (*s++)
      {
      /* ']' doesn't appear here because it's only special after ] */
      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':
          case 'S': case '=': case '{': case '}':
#ifdef MULE
          /* 97/2/25 jhod Added for category matches */
          case 'c': case 'C':
#endif /* MULE */
          case '1': case '2': case '3': case '4': case '5':
          case '6': case '7': case '8': case '9':
            return 0;
          }
      }
    }
  return 1;
}

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

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

   Returns -x if only N-x occurrences found (x > 0),
   or else the position at the beginning of the Nth occurrence
   (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.  */
static Bufpos
search_buffer (struct buffer *buf, Lisp_Object string, Bufpos bufpos,
             Bufpos buflim, EMACS_INT n, int RE, Lisp_Object trt,
             Lisp_Object inverse_trt, int posix)
{
  /* This function has been Mule-ized, except for the trt table handling. */
  Bytecount len = XSTRING_LENGTH (string);
  Bufbyte *base_pat = XSTRING_DATA (string);
  REGISTER EMACS_INT i, j;
  Bytind p1, p2;
  Bytecount s1, s2;
  Bytind pos, lim;

  if (running_asynch_code)
    save_search_regs ();

  /* Null string is found at starting position.  */
  if (len == 0)
    {
      set_search_regs (buf, bufpos, 0);
      clear_unused_search_regs (&search_regs, 0);
      return bufpos;
    }

  /* Searching 0 times means noop---don't move, don't touch registers.  */
  if (n == 0)
    return bufpos;

  pos = bufpos_to_bytind (buf, bufpos);
  lim = bufpos_to_bytind (buf, buflim);
  if (RE && !trivial_regexp_p (string))
    {
      struct re_pattern_buffer *bufp;

      bufp = compile_pattern (string, &search_regs, trt, posix,
                        ERROR_ME);

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

      p1 = BI_BUF_BEGV (buf);
      p2 = BI_BUF_CEILING_OF (buf, p1);
      s1 = p2 - p1;
      s2 = BI_BUF_ZV (buf) - p2;
      regex_match_object = Qnil;

      while (n < 0)
      {
        Bytecount val;
        QUIT;
          regex_emacs_buffer = buf;
        val = re_search_2 (bufp,
                       (char *) BI_BUF_BYTE_ADDRESS (buf, p1), s1,
                       (char *) BI_BUF_BYTE_ADDRESS (buf, p2), s2,
                             pos - BI_BUF_BEGV (buf), lim - pos, &search_regs,
                       pos - BI_BUF_BEGV (buf));

        if (val == -2)
          {
            matcher_overflow ();
          }
        if (val >= 0)
          {
            int num_regs = search_regs.num_regs;
            j = BI_BUF_BEGV (buf);
            for (i = 0; i < num_regs; i++)
            if (search_regs.start[i] >= 0)
              {
                search_regs.start[i] += j;
                search_regs.end[i] += j;
              }
            /* re_match (called from re_search et al) does this for us */
            /* clear_unused_search_regs (search_regs, bufp->no_sub);   */
            XSETBUFFER (last_thing_searched, buf);
            /* Set pos to the new position. */
            pos = search_regs.start[0];
            fixup_search_regs_for_buffer (buf);
            /* And bufpos too. */
            bufpos = search_regs.start[0];
          }
        else
          {
            return n;
          }
        n++;
      }
      while (n > 0)
      {
        Bytecount val;
        QUIT;
          regex_emacs_buffer = buf;
          val = re_search_2 (bufp,
                       (char *) BI_BUF_BYTE_ADDRESS (buf, p1), s1,
                       (char *) BI_BUF_BYTE_ADDRESS (buf, p2), s2,
                             pos - BI_BUF_BEGV (buf), lim - pos, &search_regs,
                             lim - BI_BUF_BEGV (buf));
        if (val == -2)
          {
            matcher_overflow ();
          }
        if (val >= 0)
          {
            int num_regs = search_regs.num_regs;
            j = BI_BUF_BEGV (buf);
            for (i = 0; i < num_regs; i++)
            if (search_regs.start[i] >= 0)
              {
                search_regs.start[i] += j;
                search_regs.end[i] += j;
              }
            /* re_match (called from re_search et al) does this for us */
            /* clear_unused_search_regs (search_regs, bufp->no_sub);   */
            XSETBUFFER (last_thing_searched, buf);
            /* Set pos to the new position. */
            pos = search_regs.end[0];
            fixup_search_regs_for_buffer (buf);
            /* And bufpos too. */
            bufpos = search_regs.end[0];
          }
        else
          {
            return 0 - n;
          }
        n--;
      }
      return bufpos;
    }
  else                        /* non-RE case */
    {
      int charset_base = -1;
      int boyer_moore_ok = 1;
      Bufbyte *pat = 0;
      Bufbyte *patbuf = alloca_array (Bufbyte, len * MAX_EMCHAR_LEN);
      pat = patbuf;
#ifdef MULE
      while (len > 0)
      {
        Bufbyte tmp_str[MAX_EMCHAR_LEN];
        Emchar c, translated, inverse;
        Bytecount orig_bytelen, new_bytelen, inv_bytelen;

        /* If we got here and the RE flag is set, it's because
           we're dealing with a regexp known to be trivial, so the
           backslash just quotes the next character.  */
        if (RE && *base_pat == '\\')
          {
            len--;
            base_pat++;
          }
        c = charptr_emchar (base_pat);
        translated = TRANSLATE (trt, c);
        inverse = TRANSLATE (inverse_trt, c);

        orig_bytelen = charcount_to_bytecount (base_pat, 1);
        inv_bytelen = set_charptr_emchar (tmp_str, inverse);
        new_bytelen = set_charptr_emchar (tmp_str, translated);


        if (new_bytelen != orig_bytelen || inv_bytelen != orig_bytelen)
          boyer_moore_ok = 0;
        if (translated != c || inverse != c)
          {
            /* Keep track of which character set row
             contains the characters that need translation.  */
            int charset_base_code = c & ~CHAR_FIELD3_MASK;
            if (charset_base == -1)
            charset_base = charset_base_code;
            else if (charset_base != charset_base_code)
            /* If two different rows appear, needing translation,
               then we cannot use boyer_moore search.  */
            boyer_moore_ok = 0;
          }
        memcpy (pat, tmp_str, new_bytelen);
        pat += new_bytelen;
        base_pat += orig_bytelen;
        len -= orig_bytelen;
      }
#else /* not MULE */
      while (--len >= 0)
      {
        /* If we got here and the RE flag is set, it's because
           we're dealing with a regexp known to be trivial, so the
           backslash just quotes the next character.  */
        if (RE && *base_pat == '\\')
          {
            len--;
            base_pat++;
          }
        *pat++ = TRANSLATE (trt, *base_pat++);
      }
#endif /* MULE */
      len = pat - patbuf;
      pat = base_pat = patbuf;
      if (boyer_moore_ok)
      return boyer_moore (buf, base_pat, len, pos, lim, n,
                      trt, inverse_trt, charset_base);
      else
      return simple_search (buf, base_pat, len, pos, lim, n, trt);
    }
}

/* Do a simple string search N times for the string PAT,
   whose length is LEN/LEN_BYTE,
   from buffer position POS/POS_BYTE until LIM/LIM_BYTE.
   TRT is the translation table.

   Return the character position where the match is found.
   Otherwise, if M matches remained to be found, return -M.

   This kind of search works regardless of what is in PAT and
   regardless of what is in TRT.  It is used in cases where
   boyer_moore cannot work.  */

static Bufpos
simple_search (struct buffer *buf, Bufbyte *base_pat, Bytecount len_byte,
             Bytind idx, Bytind lim, EMACS_INT n, Lisp_Object trt)
{
  int forward = n > 0;
  Bytecount buf_len = 0; /* Shut up compiler. */

  if (lim > idx)
    while (n > 0)
      {
      while (1)
        {
          Bytecount this_len = len_byte;
          Bytind this_idx = idx;
          Bufbyte *p = base_pat;
          if (idx >= lim)
            goto stop;

          while (this_len > 0)
            {
            Emchar pat_ch, buf_ch;
            Bytecount pat_len;

            pat_ch = charptr_emchar (p);
            buf_ch = BI_BUF_FETCH_CHAR (buf, this_idx);

            buf_ch = TRANSLATE (trt, buf_ch);

            if (buf_ch != pat_ch)
              break;

            pat_len = charcount_to_bytecount (p, 1);
            p += pat_len;
            this_len -= pat_len;
            INC_BYTIND (buf, this_idx);
            }
          if (this_len == 0)
            {
            buf_len = this_idx - idx;
            idx = this_idx;
            break;
            }
          INC_BYTIND (buf, idx);
        }
      n--;
      }
  else
    while (n < 0)
      {
      while (1)
        {
          Bytecount this_len = len_byte;
          Bytind this_idx = idx;
          Bufbyte *p;
          if (idx <= lim)
            goto stop;
          p = base_pat + len_byte;

          while (this_len > 0)
            {
            Emchar pat_ch, buf_ch;

            DEC_CHARPTR (p);
            DEC_BYTIND (buf, this_idx);
            pat_ch = charptr_emchar (p);
            buf_ch = BI_BUF_FETCH_CHAR (buf, this_idx);

            buf_ch = TRANSLATE (trt, buf_ch);

            if (buf_ch != pat_ch)
              break;

            this_len -= charcount_to_bytecount (p, 1);
            }
          if (this_len == 0)
            {
            buf_len = idx - this_idx;
            idx = this_idx;
            break;
            }
          DEC_BYTIND (buf, idx);
        }
      n++;
      }
 stop:
  if (n == 0)
    {
      Bufpos beg, end, retval;
      if (forward)
      {
        beg = bytind_to_bufpos (buf, idx - buf_len);
        retval = end = bytind_to_bufpos (buf, idx);
      }
      else
      {
        retval = beg = bytind_to_bufpos (buf, idx);
        end = bytind_to_bufpos (buf, idx + buf_len);
      }
      set_search_regs (buf, beg, end - beg);
      clear_unused_search_regs (&search_regs, 0);

      return retval;
    }
  else if (n > 0)
    return -n;
  else
    return n;
}

/* Do Boyer-Moore search N times for the string PAT,
   whose length is LEN/LEN_BYTE,
   from buffer position POS/POS_BYTE until LIM/LIM_BYTE.
   DIRECTION says which direction we search in.
   TRT and INVERSE_TRT are translation tables.

   This kind of search works if all the characters in PAT that have
   nontrivial translation are the same aside from the last byte.  This
   makes it possible to translate just the last byte of a character,
   and do so after just a simple test of the context.

   If that criterion is not satisfied, do not call this function.  */
          
static Bufpos
boyer_moore (struct buffer *buf, Bufbyte *base_pat, Bytecount len,
           Bytind pos, Bytind lim, EMACS_INT n, Lisp_Object trt,
           Lisp_Object inverse_trt, int charset_base)
{
  /* #### Someone really really really needs to comment the workings
     of this junk somewhat better.

     BTW "BM" stands for Boyer-Moore, which is one of the standard
     string-searching algorithms.  It's the best string-searching
     algorithm out there, provided that:

     a) You're not fazed by algorithm complexity. (Rabin-Karp, which
     uses hashing, is much much easier to code but not as fast.)
     b) You can freely move backwards in the string that you're
     searching through.

     As the comment below tries to explain (but garbles in typical
     programmer-ese), the idea is that you don't have to do a
     string match at every successive position in the text.  For
     example, let's say the pattern is "a very long string".  We
     compare the last character in the string (`g') with the
     corresponding character in the text.  If it mismatches, and
     it is, say, `z', then we can skip forward by the entire
     length of the pattern because `z' does not occur anywhere
     in the pattern.  If the mismatching character does occur
     in the pattern, we can usually still skip forward by more
     than one: e.g. if it is `l', then we can skip forward
     by the length of the substring "ong string" -- i.e. the
     largest end section of the pattern that does not contain
     the mismatched character.  So what we do is compute, for
     each possible character, the distance we can skip forward
     (the "stride") and use it in the string matching.  This
     is what the BM_tab holds. */
  REGISTER EMACS_INT *BM_tab;
  EMACS_INT *BM_tab_base;
  REGISTER Bytecount dirlen;
  EMACS_INT infinity;
  Bytind limit;
  Bytecount stride_for_teases = 0;
  REGISTER EMACS_INT i, j;
  Bufbyte *pat, *pat_end;
  REGISTER Bufbyte *cursor, *p_limit, *ptr2;
  Bufbyte simple_translate[0400];
  REGISTER int direction = ((n > 0) ? 1 : -1);
#ifdef MULE
  Bufbyte translate_prev_byte = 0;
  Bufbyte translate_anteprev_byte = 0;
#endif
#ifdef C_ALLOCA
  EMACS_INT BM_tab_space[0400];
  BM_tab = &BM_tab_space[0];
#else
  BM_tab = alloca_array (EMACS_INT, 256);
#endif
  
  /* The general approach is that we are going to maintain that we
     know the first (closest to the present position, in whatever
     direction we're searching) character that could possibly be
     the last (furthest from present position) character of a
     valid match.  We advance the state of our knowledge by
     looking at that character and seeing whether it indeed
     matches the last character of the pattern.  If it does, we
     take a closer look.  If it does not, we move our pointer (to
     putative last characters) as far as is logically possible.
     This amount of movement, which I call a stride, will be the
     length of the pattern if the actual character appears nowhere
     in the pattern, otherwise it will be the distance from the
     last occurrence of that character to the end of the pattern.
     As a coding trick, an enormous stride is coded into the table
     for characters that match the last character.  This allows
     use of only a single test, a test for having gone past the
     end of the permissible match region, to test for both
     possible matches (when the stride goes past the end
     immediately) and failure to match (where you get nudged past
     the end one stride at a time).

     Here we make a "mickey mouse" BM table.  The stride of the
     search is determined only by the last character of the
     putative match.  If that character does not match, we will
     stride the proper distance to propose a match that
     superimposes it on the last instance of a character that
     matches it (per trt), or misses it entirely if there is
     none. */

  dirlen = len * direction;
  infinity = dirlen - (lim + pos + len + len) * direction;
  /* Record position after the end of the pattern.  */
  pat_end = base_pat + len;
  if (direction < 0)
    base_pat = pat_end - 1;
  BM_tab_base = BM_tab;
  BM_tab += 0400;
  j = dirlen;           /* to get it in a register */
  /* A character that does not appear in the pattern induces a
     stride equal to the pattern length. */
  while (BM_tab_base != BM_tab)
    {
      *--BM_tab = j;
      *--BM_tab = j;
      *--BM_tab = j;
      *--BM_tab = j;
    }
  /* We use this for translation, instead of TRT itself.  We
     fill this in to handle the characters that actually occur
     in the pattern.  Others don't matter anyway!  */
  xzero (simple_translate);
  for (i = 0; i < 0400; i++)
    simple_translate[i] = (Bufbyte) i;
  i = 0;
  while (i != infinity)
    {
      Bufbyte *ptr = base_pat + i;
      i += direction;
      if (i == dirlen)
      i = infinity;
      if (!NILP (trt))
      {
#ifdef MULE
        Emchar ch, untranslated;
        int this_translated = 1;

        /* Is *PTR the last byte of a character?  */
        if (pat_end - ptr == 1 || BUFBYTE_FIRST_BYTE_P (ptr[1]))
          {
            Bufbyte *charstart = ptr;
            while (!BUFBYTE_FIRST_BYTE_P (*charstart))
            charstart--;
            untranslated = charptr_emchar (charstart);
            if (charset_base == (untranslated & ~CHAR_FIELD3_MASK))
            {
              ch = TRANSLATE (trt, untranslated);
              if (!BUFBYTE_FIRST_BYTE_P (*ptr))
                {
                  translate_prev_byte = ptr[-1];
                  if (!BUFBYTE_FIRST_BYTE_P (translate_prev_byte))
                  translate_anteprev_byte = ptr[-2];
                }
            }
            else
            {
              this_translated = 0;
              ch = *ptr;
            }
          }
        else
          {
            ch = *ptr;
            this_translated = 0;
          }
        if (ch > 0400)
          j = ((unsigned char) ch | 0200);
        else
          j = (unsigned char) ch;
            
        if (i == infinity)
          stride_for_teases = BM_tab[j];
        BM_tab[j] = dirlen - i;
        /* A translation table is accompanied by its inverse --
           see comment following downcase_table for details */
        if (this_translated)
          {
            Emchar starting_ch = ch;
            EMACS_INT starting_j = j;
            while (1)
            {
              ch = TRANSLATE (inverse_trt, ch);
              if (ch > 0400)
                j = ((unsigned char) ch | 0200);
              else
                j = (unsigned char) ch;

              /* For all the characters that map into CH,
                 set up simple_translate to map the last byte
                 into STARTING_J.  */
              simple_translate[j] = starting_j;
              if (ch == starting_ch)
                break;
              BM_tab[j] = dirlen - i;
            }
          }
#else
        EMACS_INT k;
        j = *ptr;
        k = (j = TRANSLATE (trt, j));
        if (i == infinity)
          stride_for_teases = BM_tab[j];
        BM_tab[j] = dirlen - i;
        /* A translation table is accompanied by its inverse --
           see comment following downcase_table for details */

        while ((j = TRANSLATE (inverse_trt, j)) != k)
          {
            simple_translate[j] = (Bufbyte) k;
            BM_tab[j] = dirlen - i;
          }
#endif
      }
      else
      {
        j = *ptr;

        if (i == infinity)
          stride_for_teases = BM_tab[j];
        BM_tab[j] = dirlen - i;
      }
      /* stride_for_teases tells how much to stride if we get a
       match on the far character but are subsequently
       disappointed, by recording what the stride would have been
       for that character if the last character had been
       different. */
    }
  infinity = dirlen - infinity;
  pos += dirlen - ((direction > 0) ? direction : 0);
  /* loop invariant - pos points at where last char (first char if
     reverse) of pattern would align in a possible match.  */
  while (n != 0)
    {
      Bytind tail_end;
      Bufbyte *tail_end_ptr;
      /* It's been reported that some (broken) compiler thinks
       that Boolean expressions in an arithmetic context are
       unsigned.  Using an explicit ?1:0 prevents this.  */
      if ((lim - pos - ((direction > 0) ? 1 : 0)) * direction < 0)
      return n * (0 - direction);
      /* First we do the part we can by pointers (maybe
       nothing) */
      QUIT;
      pat = base_pat;
      limit = pos - dirlen + direction;
      /* XEmacs change: definitions of CEILING_OF and FLOOR_OF
       have changed.  See buffer.h. */
      limit = ((direction > 0)
             ? BI_BUF_CEILING_OF (buf, limit) - 1
             : BI_BUF_FLOOR_OF (buf, limit + 1));
      /* LIMIT is now the last (not beyond-last!) value POS can
       take on without hitting edge of buffer or the gap.  */
      limit = ((direction > 0)
             ? min (lim - 1, min (limit, pos + 20000))
             : max (lim, max (limit, pos - 20000)));
      tail_end = BI_BUF_CEILING_OF (buf, pos);
      tail_end_ptr = BI_BUF_BYTE_ADDRESS (buf, tail_end);

      if ((limit - pos) * direction > 20)
      {
        p_limit = BI_BUF_BYTE_ADDRESS (buf, limit);
        ptr2 = (cursor = BI_BUF_BYTE_ADDRESS (buf, pos));
        /* In this loop, pos + cursor - ptr2 is the surrogate
           for pos */
        while (1) /* use one cursor setting as long as i can */
          {
            if (direction > 0) /* worth duplicating */
            {
              /* Use signed comparison if appropriate to make
                 cursor+infinity sure to be > p_limit.
                 Assuming that the buffer lies in a range of
                 addresses that are all "positive" (as ints)
                 or all "negative", either kind of comparison
                 will work as long as we don't step by
                 infinity.  So pick the kind that works when
                 we do step by infinity.  */
              if ((EMACS_INT) (p_limit + infinity) >
                  (EMACS_INT) p_limit)
                while ((EMACS_INT) cursor <=
                     (EMACS_INT) p_limit)
                  cursor += BM_tab[*cursor];
              else
                while ((EMACS_UINT) cursor <=
                     (EMACS_UINT) p_limit)
                  cursor += BM_tab[*cursor];
            }
            else
            {
              if ((EMACS_INT) (p_limit + infinity) <
                  (EMACS_INT) p_limit)
                while ((EMACS_INT) cursor >=
                     (EMACS_INT) p_limit)
                  cursor += BM_tab[*cursor];
              else
                while ((EMACS_UINT) cursor >=
                     (EMACS_UINT) p_limit)
                  cursor += BM_tab[*cursor];
            }
            /* If you are here, cursor is beyond the end of the
             searched region.  This can happen if you match on
             the far character of the pattern, because the
             "stride" of that character is infinity, a number
             able to throw you well beyond the end of the
             search.  It can also happen if you fail to match
             within the permitted region and would otherwise
             try a character beyond that region */
            if ((cursor - p_limit) * direction <= len)
            break;      /* a small overrun is genuine */
            cursor -= infinity; /* large overrun = hit */
            i = dirlen - direction;
            if (!NILP (trt))
            {
              while ((i -= direction) + direction != 0)
                {
#ifdef MULE
                  Emchar ch;
                  cursor -= direction;
                  /* Translate only the last byte of a character.  */
                  if ((cursor == tail_end_ptr
                     || BUFBYTE_FIRST_BYTE_P (cursor[1]))
                    && (BUFBYTE_FIRST_BYTE_P (cursor[0])
                        || (translate_prev_byte == cursor[-1]
                          && (BUFBYTE_FIRST_BYTE_P (translate_prev_byte)
                              || translate_anteprev_byte == cursor[-2]))))
                  ch = simple_translate[*cursor];
                  else
                  ch = *cursor;
                  if (pat[i] != ch)
                  break;
#else
                  if (pat[i] != TRANSLATE (trt, *(cursor -= direction)))
                  break;
#endif
                }
            }
            else
            {
              while ((i -= direction) + direction != 0)
                if (pat[i] != *(cursor -= direction))
                  break;
            }
            cursor += dirlen - i - direction;   /* fix cursor */
            if (i + direction == 0)
            {
              cursor -= direction;

              {
                Bytind bytstart = (pos + cursor - ptr2 +
                               ((direction > 0)
                              ? 1 - len : 0));
                Bufpos bufstart = bytind_to_bufpos (buf, bytstart);
                Bufpos bufend = bytind_to_bufpos (buf, bytstart + len);

                set_search_regs (buf, bufstart, bufend - bufstart);
                clear_unused_search_regs (&search_regs, 0);
              }

              if ((n -= direction) != 0)
                cursor += dirlen; /* to resume search */
              else
                return ((direction > 0)
                      ? search_regs.end[0] : search_regs.start[0]);
            }
            else
            cursor += stride_for_teases; /* <sigh> we lose -  */
          }
        pos += cursor - ptr2;
      }
      else
      /* Now we'll pick up a clump that has to be done the hard
         way because it covers a discontinuity */
      {
        /* XEmacs change: definitions of CEILING_OF and FLOOR_OF
           have changed.  See buffer.h. */
        limit = ((direction > 0)
               ? BI_BUF_CEILING_OF (buf, pos - dirlen + 1) - 1
               : BI_BUF_FLOOR_OF (buf, pos - dirlen));
        limit = ((direction > 0)
               ? min (limit + len, lim - 1)
               : max (limit - len, lim));
        /* LIMIT is now the last value POS can have
           and still be valid for a possible match.  */
        while (1)
          {
            /* This loop can be coded for space rather than
             speed because it will usually run only once.
             (the reach is at most len + 21, and typically
             does not exceed len) */
            while ((limit - pos) * direction >= 0)
            /* *not* BI_BUF_FETCH_CHAR.  We are working here
               with bytes, not characters. */
            pos += BM_tab[*BI_BUF_BYTE_ADDRESS (buf, pos)];
            /* now run the same tests to distinguish going off
             the end, a match or a phony match. */
            if ((pos - limit) * direction <= len)
            break;      /* ran off the end */
            /* Found what might be a match.
             Set POS back to last (first if reverse) char pos.  */
            pos -= infinity;
            i = dirlen - direction;
            while ((i -= direction) + direction != 0)
            {
#ifdef MULE
              Emchar ch;
              Bufbyte *ptr;
#endif
              pos -= direction;
#ifdef MULE
              ptr = BI_BUF_BYTE_ADDRESS (buf, pos);
              if ((ptr == tail_end_ptr
                   || BUFBYTE_FIRST_BYTE_P (ptr[1]))
                  && (BUFBYTE_FIRST_BYTE_P (ptr[0])
                    || (translate_prev_byte == ptr[-1]
                        && (BUFBYTE_FIRST_BYTE_P (translate_prev_byte)
                          || translate_anteprev_byte == ptr[-2]))))
                ch = simple_translate[*ptr];
              else
                ch = *ptr;
              if (pat[i] != ch)
                break;
                  
#else
              if (pat[i] != TRANSLATE (trt,
                                 *BI_BUF_BYTE_ADDRESS (buf, pos)))
                break;
#endif
            }
            /* Above loop has moved POS part or all the way back
             to the first char pos (last char pos if reverse).
             Set it once again at the last (first if reverse)
             char.  */
            pos += dirlen - i- direction;
            if (i + direction == 0)
            {
              pos -= direction;

              {
                Bytind bytstart = (pos +
                               ((direction > 0)
                              ? 1 - len : 0));
                Bufpos bufstart = bytind_to_bufpos (buf, bytstart);
                Bufpos bufend = bytind_to_bufpos (buf, bytstart + len);

                set_search_regs (buf, bufstart, bufend - bufstart);
                clear_unused_search_regs (&search_regs, 0);
              }

              if ((n -= direction) != 0)
                pos += dirlen; /* to resume search */
              else
                return ((direction > 0)
                      ? search_regs.end[0] : search_regs.start[0]);
            }
            else
            pos += stride_for_teases;
          }
      }
      /* We have done one clump.  Can we continue? */
      if ((lim - pos) * direction < 0)
      return (0 - n) * direction;
    }
  return bytind_to_bufpos (buf, pos);
}

/* Record the whole-match data (beginning BEG and end BEG + LEN) and the
   buffer for a match just found.  */

static void
set_search_regs (struct buffer *buf, Bufpos beg, Charcount len)
{
  /* This function has been Mule-ized. */
  /* Make sure we have registers in which to store
     the match position.  */
  if (search_regs.num_regs == 0)
    {
      search_regs.start = xnew (regoff_t);
      search_regs.end   = xnew (regoff_t);
      search_regs.num_regs = 1;
    }

  search_regs.start[0] = beg;
  search_regs.end[0] = beg + len;
  XSETBUFFER (last_thing_searched, buf);
}

/* Clear unused search registers so match data will be null.
   REGP is a pointer to the register structure to clear, usually the global
   search_regs.
   NO_SUB is the number of subexpressions to allow for.  (Does not count
   the whole match, ie, for a string search NO_SUB == 0.)
   It is an error if NO_SUB > REGP.num_regs - 1. */

static void
clear_unused_search_regs (struct re_registers *regp, int no_sub)
{
  /* This function has been Mule-ized. */
  int i;

  assert (no_sub >= 0 && no_sub < regp->num_regs);
  for (i = no_sub + 1; i < regp->num_regs; i++)
    regp->start[i] = regp->end[i] = -1;
}


/* Given a string of words separated by word delimiters,
   compute a regexp that matches those exact words
   separated by arbitrary punctuation.  */

static Lisp_Object
wordify (Lisp_Object buffer, Lisp_Object string)
{
  Charcount i, len;
  EMACS_INT punct_count = 0, word_count = 0;
  struct buffer *buf = decode_buffer (buffer, 0);
  Lisp_Char_Table *syntax_table = XCHAR_TABLE (buf->mirror_syntax_table);

  CHECK_STRING (string);
  len = XSTRING_CHAR_LENGTH (string);

  for (i = 0; i < len; i++)
    if (!WORD_SYNTAX_P (syntax_table, string_char (XSTRING (string), i)))
      {
      punct_count++;
      if (i > 0 && WORD_SYNTAX_P (syntax_table,
                            string_char (XSTRING (string), i - 1)))
          word_count++;
      }
  if (WORD_SYNTAX_P (syntax_table, string_char (XSTRING (string), len - 1)))
    word_count++;
  if (!word_count) return build_string ("");

  {
    /* The following value is an upper bound on the amount of storage we
       need.  In non-Mule, it is exact. */
    Bufbyte *storage =
      (Bufbyte *) alloca (XSTRING_LENGTH (string) - punct_count +
                          5 * (word_count - 1) + 4);
    Bufbyte *o = storage;

    *o++ = '\\';
    *o++ = 'b';

    for (i = 0; i < len; i++)
      {
      Emchar ch = string_char (XSTRING (string), i);

      if (WORD_SYNTAX_P (syntax_table, ch))
        o += set_charptr_emchar (o, ch);
      else if (i > 0
             && WORD_SYNTAX_P (syntax_table,
                           string_char (XSTRING (string), i - 1))
             && --word_count)
        {
          *o++ = '\\';
          *o++ = 'W';
          *o++ = '\\';
          *o++ = 'W';
          *o++ = '*';
        }
      }

    *o++ = '\\';
    *o++ = 'b';

    return make_string (storage, o - storage);
  }
}

DEFUN ("search-backward", Fsearch_backward, 1, 5, "sSearch backward: ", /*
Search backward from point for STRING.
Set point to the beginning of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend before that position.
The value nil is equivalent to (point-min).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (string, limit, noerror, count, buffer))
{
  return search_command (string, limit, noerror, count, buffer, -1, 0, 0);
}

DEFUN ("search-forward", Fsearch_forward, 1, 5, "sSearch: ", /*
Search forward from point for STRING.
Set point to the end of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend after that position.  The
value nil is equivalent to (point-max).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (string, limit, noerror, count, buffer))
{
  return search_command (string, limit, noerror, count, buffer, 1, 0, 0);
}

DEFUN ("word-search-backward", Fword_search_backward, 1, 5,
       "sWord search backward: ", /*
Search backward from point for STRING, ignoring differences in punctuation.
Set point to the beginning of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend before that position.
The value nil is equivalent to (point-min).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (string, limit, noerror, count, buffer))
{
  return search_command (wordify (buffer, string), limit, noerror, count,
                   buffer, -1, 1, 0);
}

DEFUN ("word-search-forward", Fword_search_forward, 1, 5, "sWord search: ", /*
Search forward from point for STRING, ignoring differences in punctuation.
Set point to the end of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend after that position.  The
value nil is equivalent to (point-max).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (string, limit, noerror, count, buffer))
{
  return search_command (wordify (buffer, string), limit, noerror, count,
                   buffer, 1, 1, 0);
}

DEFUN ("re-search-backward", Fre_search_backward, 1, 5,
       "sRE search backward: ", /*
Search backward from point for match for regular expression REGEXP.
Set point to the beginning of the match, and return point.
The match found is the one starting last in the buffer
and yet ending before the origin of the search.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend before that position.
The value nil is equivalent to (point-min).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (regexp, limit, noerror, count, buffer))
{
  return search_command (regexp, limit, noerror, count, buffer, -1, 1, 0);
}

DEFUN ("re-search-forward", Fre_search_forward, 1, 5, "sRE search: ", /*
Search forward from point for regular expression REGEXP.
Set point to the end of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend after that position.  The
value nil is equivalent to (point-max).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (regexp, limit, noerror, count, buffer))
{
  return search_command (regexp, limit, noerror, count, buffer, 1, 1, 0);
}

DEFUN ("posix-search-backward", Fposix_search_backward, 1, 5,
       "sPosix search backward: ", /*
Search backward from point for match for regular expression REGEXP.
Find the longest match in accord with Posix regular expression rules.
Set point to the beginning of the match, and return point.
The match found is the one starting last in the buffer
and yet ending before the origin of the search.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend before that position.
The value nil is equivalent to (point-min).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (regexp, limit, noerror, count, buffer))
{
  return search_command (regexp, limit, noerror, count, buffer, -1, 1, 1);
}

DEFUN ("posix-search-forward", Fposix_search_forward, 1, 5, "sPosix search: ", /*
Search forward from point for regular expression REGEXP.
Find the longest match in accord with Posix regular expression rules.
Set point to the end of the occurrence found, and return point.

Optional second argument LIMIT bounds the search; it is a buffer
position.  The match found must not extend after that position.  The
value nil is equivalent to (point-max).

Optional third argument NOERROR, if t, means just return nil (no
error) if the search fails.  If neither nil nor t, set point to LIMIT
and return nil.

Optional fourth argument COUNT is a repeat count--search for
successive occurrences.

Optional fifth argument BUFFER specifies the buffer to search in and
defaults to the current buffer.

See also the functions `match-beginning', `match-end' and `replace-match'.
*/
       (regexp, limit, noerror, count, buffer))
{
  return search_command (regexp, limit, noerror, count, buffer, 1, 1, 1);
}


static Lisp_Object
free_created_dynarrs (Lisp_Object cons)
{
  Dynarr_free (get_opaque_ptr (XCAR (cons)));
  Dynarr_free (get_opaque_ptr (XCDR (cons)));
  free_opaque_ptr (XCAR (cons));
  free_opaque_ptr (XCDR (cons));
  free_cons (XCONS (cons));
  return Qnil;
}

DEFUN ("replace-match", Freplace_match, 1, 5, 0, /*
Replace text matched by last search with REPLACEMENT.
If second arg FIXEDCASE is non-nil, do not alter case of replacement text.
Otherwise maybe capitalize the whole text, or maybe just word initials,
based on the replaced text.
If the replaced text has only capital letters
and has at least one multiletter word, convert REPLACEMENT to all caps.
If the replaced text has at least one word starting with a capital letter,
then capitalize each word in REPLACEMENT.

If third arg LITERAL is non-nil, insert REPLACEMENT literally.
Otherwise treat `\\' as special:
  `\\&' in REPLACEMENT means substitute original matched text.
  `\\N' means substitute what matched the Nth `\\(...\\)'.
       If Nth parens didn't match, substitute nothing.
  `\\\\' means insert one `\\'.
  `\\u' means upcase the next character.
  `\\l' means downcase the next character.
  `\\U' means begin upcasing all following characters.
  `\\L' means begin downcasing all following characters.
  `\\E' means terminate the effect of any `\\U' or `\\L'.
  Case changes made with `\\u', `\\l', `\\U', and `\\L' override
  all other case changes that may be made in the replaced text.
FIXEDCASE and LITERAL are optional arguments.
Leaves point at end of replacement text.

The optional fourth argument STRING can be a string to modify.
In that case, this function creates and returns a new string
which is made by replacing the part of STRING that was matched.
When fourth argument is a string, fifth argument STRBUFFER specifies
the buffer to be used for syntax-table and case-table lookup and
defaults to the current buffer.  When fourth argument is not a string,
the buffer that the match occurred in has automatically been remembered
and you do not need to specify it.

When fourth argument is nil, STRBUFFER specifies a subexpression of
the match.  It says to replace just that subexpression instead of the
whole match.  This is useful only after a regular expression search or
match since only regular expressions have distinguished subexpressions.
*/
       (replacement, fixedcase, literal, string, strbuffer))
{
  /* This function has been Mule-ized. */
  /* This function can GC */
  enum { nochange, all_caps, cap_initial } case_action;
  Bufpos pos, last;
  int some_multiletter_word;
  int some_lowercase;
  int some_uppercase;
  int some_nonuppercase_initial;
  Emchar c, prevc;
  Charcount inslen;
  struct buffer *buf;
  Lisp_Char_Table *syntax_table;
  int mc_count;
  Lisp_Object buffer;
  int_dynarr *ul_action_dynarr = 0;
  int_dynarr *ul_pos_dynarr = 0;
  int sub = 0;
  int speccount;

  CHECK_STRING (replacement);

  if (! NILP (string))
    {
      CHECK_STRING (string);
      if (!EQ (last_thing_searched, Qt))
      error ("last thing matched was not a string");
      /* If the match data
       were abstracted into a special "match data" type instead
       of the typical half-assed "let the implementation be
       visible" form it's in, we could extend it to include
       the last string matched and the buffer used for that
       matching.  But of course we can't change it as it is. */
      buf = decode_buffer (strbuffer, 0);
      XSETBUFFER (buffer, buf);
    }
  else
    {
      if (!NILP (strbuffer))
      {
        CHECK_INT (strbuffer);
        sub = XINT (strbuffer);
        if (sub < 0 || sub >= (int) search_regs.num_regs)
          args_out_of_range (strbuffer, make_int (search_regs.num_regs));
      }
      if (!BUFFERP (last_thing_searched))
      error ("last thing matched was not a buffer");
      buffer = last_thing_searched;
      buf = XBUFFER (buffer);
    }

  syntax_table = XCHAR_TABLE (buf->mirror_syntax_table);

  case_action = nochange;     /* We tried an initialization */
                        /* but some C compilers blew it */

  if (search_regs.num_regs == 0)
    error ("replace-match called before any match found");

  if (NILP (string))
    {
      if (search_regs.start[sub] < BUF_BEGV (buf)
        || search_regs.start[sub] > search_regs.end[sub]
        || search_regs.end[sub] > BUF_ZV (buf))
      args_out_of_range (make_int (search_regs.start[sub]),
                     make_int (search_regs.end[sub]));
    }
  else
    {
      if (search_regs.start[0] < 0
        || search_regs.start[0] > search_regs.end[0]
        || search_regs.end[0] > XSTRING_CHAR_LENGTH (string))
      args_out_of_range (make_int (search_regs.start[0]),
                     make_int (search_regs.end[0]));
    }

  if (NILP (fixedcase))
    {
      /* Decide how to casify by examining the matched text. */

      last = search_regs.end[sub];
      prevc = '\n';
      case_action = all_caps;

      /* some_multiletter_word is set nonzero if any original word
       is more than one letter long. */
      some_multiletter_word = 0;
      some_lowercase = 0;
      some_nonuppercase_initial = 0;
      some_uppercase = 0;

      for (pos = search_regs.start[sub]; pos < last; pos++)
      {
        if (NILP (string))
          c = BUF_FETCH_CHAR (buf, pos);
        else
          c = string_char (XSTRING (string), pos);

        if (LOWERCASEP (buf, c))
          {
            /* Cannot be all caps if any original char is lower case */

            some_lowercase = 1;
            if (!WORD_SYNTAX_P (syntax_table, prevc))
            some_nonuppercase_initial = 1;
            else
            some_multiletter_word = 1;
          }
        else if (!NOCASEP (buf, c))
          {
            some_uppercase = 1;
            if (!WORD_SYNTAX_P (syntax_table, prevc))
            ;
            else
            some_multiletter_word = 1;
          }
        else
          {
            /* If the initial is a caseless word constituent,
             treat that like a lowercase initial.  */
            if (!WORD_SYNTAX_P (syntax_table, prevc))
            some_nonuppercase_initial = 1;
          }

        prevc = c;
      }

      /* Convert to all caps if the old text is all caps
       and has at least one multiletter word.  */
      if (! some_lowercase && some_multiletter_word)
      case_action = all_caps;
      /* Capitalize each word, if the old text has all capitalized words.  */
      else if (!some_nonuppercase_initial && some_multiletter_word)
      case_action = cap_initial;
      else if (!some_nonuppercase_initial && some_uppercase)
      /* Should x -> yz, operating on X, give Yz or YZ?
         We'll assume the latter.  */
      case_action = all_caps;
      else
      case_action = nochange;
    }

  /* Do replacement in a string.  */
  if (!NILP (string))
    {
      Lisp_Object before, after;

      speccount = specpdl_depth ();
      before = Fsubstring (string, Qzero, make_int (search_regs.start[0]));
      after = Fsubstring (string, make_int (search_regs.end[0]), Qnil);

      /* Do case substitution into REPLACEMENT if desired.  */
      if (NILP (literal))
      {
        Charcount stlen = XSTRING_CHAR_LENGTH (replacement);
        Charcount strpos;
        /* XEmacs change: rewrote this loop somewhat to make it
           cleaner.  Also added \U, \E, etc. */
        Charcount literal_start = 0;
        /* We build up the substituted string in ACCUM.  */
        Lisp_Object accum;

        accum = Qnil;

        /* OK, the basic idea here is that we scan through the
           replacement string until we find a backslash, which
           represents a substring of the original string to be
           substituted.  We then append onto ACCUM the literal
           text before the backslash (LASTPOS marks the
           beginning of this) followed by the substring of the
           original string that needs to be inserted. */
        for (strpos = 0; strpos < stlen; strpos++)
          {
            /* If LITERAL_END is set, we've encountered a backslash
             (the end of literal text to be inserted). */
            Charcount literal_end = -1;
            /* If SUBSTART is set, we need to also insert the
             text from SUBSTART to SUBEND in the original string. */
            Charcount substart = -1;
            Charcount subend   = -1;

            c = string_char (XSTRING (replacement), strpos);
            if (c == '\\' && strpos < stlen - 1)
            {
              c = string_char (XSTRING (replacement), ++strpos);
              if (c == '&')
                {
                  literal_end = strpos - 1;
                  substart = search_regs.start[0];
                  subend = search_regs.end[0];
                }
              else if (c >= '1' && c <= '9' &&
                     c <= search_regs.num_regs + '0')
                {
                  if (search_regs.start[c - '0'] >= 0)
                  {
                    literal_end = strpos - 1;
                    substart = search_regs.start[c - '0'];
                    subend = search_regs.end[c - '0'];
                  }
                }
              else if (c == 'U' || c == 'u' || c == 'L' || c == 'l' ||
                     c == 'E')
                {
                  /* Keep track of all case changes requested, but don't
                   make them now.  Do them later so we override
                   everything else. */
                  if (!ul_pos_dynarr)
                  {
                    ul_pos_dynarr = Dynarr_new (int);
                    ul_action_dynarr = Dynarr_new (int);
                    record_unwind_protect
                      (free_created_dynarrs,
                       noseeum_cons
                       (make_opaque_ptr (ul_pos_dynarr),
                        make_opaque_ptr (ul_action_dynarr)));
                  }
                  literal_end = strpos - 1;
                  Dynarr_add (ul_pos_dynarr,
                          (!NILP (accum)
                          ? XSTRING_CHAR_LENGTH (accum)
                          : 0) + (literal_end - literal_start));
                  Dynarr_add (ul_action_dynarr, c);
                }
              else if (c == '\\')
                /* So we get just one backslash. */
                literal_end = strpos;
            }
            if (literal_end >= 0)
            {
              Lisp_Object literal_text = Qnil;
              Lisp_Object substring = Qnil;
              if (literal_end != literal_start)
                literal_text = Fsubstring (replacement,
                                     make_int (literal_start),
                                     make_int (literal_end));
              if (substart >= 0 && subend != substart)
                substring = Fsubstring (string,
                                  make_int (substart),
                                  make_int (subend));
              if (!NILP (literal_text) || !NILP (substring))
                accum = concat3 (accum, literal_text, substring);
              literal_start = strpos + 1;
            }
          }

        if (strpos != literal_start)
          /* some literal text at end to be inserted */
          replacement = concat2 (accum, Fsubstring (replacement,
                                          make_int (literal_start),
                                          make_int (strpos)));
        else
          replacement = accum;
      }

      /* replacement can be nil. */
      if (NILP (replacement))
      replacement = build_string ("");

      if (case_action == all_caps)
      replacement = Fupcase (replacement, buffer);
      else if (case_action == cap_initial)
      replacement = Fupcase_initials (replacement, buffer);

      /* Now finally, we need to process the \U's, \E's, etc. */
      if (ul_pos_dynarr)
      {
        int i = 0;
        int cur_action = 'E';
        Charcount stlen = XSTRING_CHAR_LENGTH (replacement);
        Charcount strpos;

        for (strpos = 0; strpos < stlen; strpos++)
          {
            Emchar curchar = string_char (XSTRING (replacement), strpos);
            Emchar newchar = -1;
            if (i < Dynarr_length (ul_pos_dynarr) &&
              strpos == Dynarr_at (ul_pos_dynarr, i))
            {
              int new_action = Dynarr_at (ul_action_dynarr, i);
              i++;
              if (new_action == 'u')
                newchar = UPCASE (buf, curchar);
              else if (new_action == 'l')
                newchar = DOWNCASE (buf, curchar);
              else
                cur_action = new_action;
            }
            if (newchar == -1)
            {
              if (cur_action == 'U')
                newchar = UPCASE (buf, curchar);
              else if (cur_action == 'L')
                newchar = DOWNCASE (buf, curchar);
              else
                newchar = curchar;
            }
            if (newchar != curchar)
            set_string_char (XSTRING (replacement), strpos, newchar);
          }
      }

      /* frees the Dynarrs if necessary. */
      unbind_to (speccount, Qnil);
      return concat3 (before, replacement, after);
    }

  mc_count = begin_multiple_change (buf, search_regs.start[sub],
                            search_regs.end[sub]);

  /* begin_multiple_change() records an unwind-protect, so we need to
     record this value now. */
  speccount = specpdl_depth ();

  /* We insert the replacement text before the old text, and then
     delete the original text.  This means that markers at the
     beginning or end of the original will float to the corresponding
     position in the replacement.  */
  BUF_SET_PT (buf, search_regs.start[sub]);
  if (!NILP (literal))
    Finsert (1, &replacement);
  else
    {
      Charcount stlen = XSTRING_CHAR_LENGTH (replacement);
      Charcount strpos;
      struct gcpro gcpro1;
      GCPRO1 (replacement);
      for (strpos = 0; strpos < stlen; strpos++)
      {
        /* on the first iteration assert(offset==0),
           exactly complementing BUF_SET_PT() above.
           During the loop, it keeps track of the amount inserted.
         */
        Charcount offset = BUF_PT (buf) - search_regs.start[sub];

        c = string_char (XSTRING (replacement), strpos);
        if (c == '\\' && strpos < stlen - 1)
          {
            /* XXX FIXME: replacing just a substring non-literally
             using backslash refs to the match looks dangerous.  But
             <15366.18513.698042.156573@ns.caldera.de> from Torsten Duwe
             <duwe@caldera.de> claims Finsert_buffer_substring already
             handles this correctly.
            */
            c = string_char (XSTRING (replacement), ++strpos);
            if (c == '&')
            Finsert_buffer_substring
                  (buffer,
                   make_int (search_regs.start[0] + offset),
                   make_int (search_regs.end[0] + offset));
            else if (c >= '1' && c <= '9' &&
                   c <= search_regs.num_regs + '0')
            {
              if (search_regs.start[c - '0'] >= 1)
                Finsert_buffer_substring
                      (buffer,
                       make_int (search_regs.start[c - '0'] + offset),
                       make_int (search_regs.end[c - '0'] + offset));
            }
            else if (c == 'U' || c == 'u' || c == 'L' || c == 'l' ||
                   c == 'E')
            {
              /* Keep track of all case changes requested, but don't
                 make them now.  Do them later so we override
                 everything else. */
              if (!ul_pos_dynarr)
                {
                  ul_pos_dynarr = Dynarr_new (int);
                  ul_action_dynarr = Dynarr_new (int);
                  record_unwind_protect
                  (free_created_dynarrs,
                   Fcons (make_opaque_ptr (ul_pos_dynarr),
                        make_opaque_ptr (ul_action_dynarr)));
                }
              Dynarr_add (ul_pos_dynarr, BUF_PT (buf));
              Dynarr_add (ul_action_dynarr, c);
            }
            else
            buffer_insert_emacs_char (buf, c);
          }
        else
          buffer_insert_emacs_char (buf, c);
      }
      UNGCPRO;
    }

  inslen = BUF_PT (buf) - (search_regs.start[sub]);
  buffer_delete_range (buf, search_regs.start[sub] + inslen,
                   search_regs.end[sub] +  inslen, 0);

  if (case_action == all_caps)
    Fupcase_region (make_int (BUF_PT (buf) - inslen),
                make_int (BUF_PT (buf)),  buffer);
  else if (case_action == cap_initial)
    Fupcase_initials_region (make_int (BUF_PT (buf) - inslen),
                       make_int (BUF_PT (buf)), buffer);

  /* Now go through and make all the case changes that were requested
     in the replacement string. */
  if (ul_pos_dynarr)
    {
      Bufpos eend = BUF_PT (buf);
      int i = 0;
      int cur_action = 'E';

      for (pos = BUF_PT (buf) - inslen; pos < eend; pos++)
      {
        Emchar curchar = BUF_FETCH_CHAR (buf, pos);
        Emchar newchar = -1;
        if (i < Dynarr_length (ul_pos_dynarr) &&
            pos == Dynarr_at (ul_pos_dynarr, i))
          {
            int new_action = Dynarr_at (ul_action_dynarr, i);
            i++;
            if (new_action == 'u')
            newchar = UPCASE (buf, curchar);
            else if (new_action == 'l')
            newchar = DOWNCASE (buf, curchar);
            else
            cur_action = new_action;
          }
        if (newchar == -1)
          {
            if (cur_action == 'U')
            newchar = UPCASE (buf, curchar);
            else if (cur_action == 'L')
            newchar = DOWNCASE (buf, curchar);
            else
            newchar = curchar;
          }
        if (newchar != curchar)
          buffer_replace_char (buf, pos, newchar, 0, 0);
      }
    }

  /* frees the Dynarrs if necessary. */
  unbind_to (speccount, Qnil);
  end_multiple_change (buf, mc_count);

  return Qnil;
}

static Lisp_Object
match_limit (Lisp_Object num, int beginningp)
{
  /* This function has been Mule-ized. */
  int n;

  CHECK_INT (num);
  n = XINT (num);
  if (n < 0 || search_regs.num_regs <= 0)
    args_out_of_range (num, make_int (search_regs.num_regs));
  if (n >= search_regs.num_regs ||
      search_regs.start[n] < 0)
    return Qnil;
  return make_int (beginningp ? search_regs.start[n] : search_regs.end[n]);
}

DEFUN ("match-beginning", Fmatch_beginning, 1, 1, 0, /*
Return position of start of text matched by last regexp search.
NUM, specifies which parenthesized expression in the last regexp.
 Value is nil if NUMth pair didn't match, or there were less than NUM pairs.
Zero means the entire text matched by the whole regexp or whole string.
*/
       (num))
{
  return match_limit (num, 1);
}

DEFUN ("match-end", Fmatch_end, 1, 1, 0, /*
Return position of end of text matched by last regexp search.
NUM specifies which parenthesized expression in the last regexp.
 Value is nil if NUMth pair didn't match, or there were less than NUM pairs.
Zero means the entire text matched by the whole regexp or whole string.
*/
       (num))
{
  return match_limit (num, 0);
}

DEFUN ("match-data", Fmatch_data, 0, 2, 0, /*
Return a list containing all info on what the last regexp search matched.
Element 2N is `(match-beginning N)'; element 2N + 1 is `(match-end N)'.
All the elements are markers or nil (nil if the Nth pair didn't match)
if the last match was on a buffer; integers or nil if a string was matched.
Use `store-match-data' to reinstate the data in this list.

If INTEGERS (the optional first argument) is non-nil, always use integers
\(rather than markers) to represent buffer positions.
If REUSE is a list, reuse it as part of the value.  If REUSE is long enough
to hold all the values, and if INTEGERS is non-nil, no consing is done.
*/
       (integers, reuse))
{
  /* This function has been Mule-ized. */
  Lisp_Object tail, prev;
  Lisp_Object *data;
  int i;
  Charcount len;

  if (NILP (last_thing_searched))
    /*error ("match-data called before any match found");*/
    return Qnil;

  data = alloca_array (Lisp_Object, 2 * search_regs.num_regs);

  len = -1;
  for (i = 0; i < search_regs.num_regs; i++)
    {
      Bufpos start = search_regs.start[i];
      if (start >= 0)
      {
        if (EQ (last_thing_searched, Qt)
            || !NILP (integers))
          {
            data[2 * i] = make_int (start);
            data[2 * i + 1] = make_int (search_regs.end[i]);
          }
        else if (BUFFERP (last_thing_searched))
          {
            data[2 * i] = Fmake_marker ();
            Fset_marker (data[2 * i],
                     make_int (start),
                     last_thing_searched);
            data[2 * i + 1] = Fmake_marker ();
            Fset_marker (data[2 * i + 1],
                     make_int (search_regs.end[i]),
                     last_thing_searched);
          }
        else
          /* last_thing_searched must always be Qt, a buffer, or Qnil.  */
          ABORT ();

        len = i;
      }
      else
      data[2 * i] = data [2 * i + 1] = Qnil;
    }
  if (!CONSP (reuse))
    return Flist (2 * len + 2, data);

  /* If REUSE is a list, store as many value elements as will fit
     into the elements of REUSE.  */
  for (prev = Qnil, i = 0, tail = reuse; CONSP (tail); i++, tail = XCDR (tail))
    {
      if (i < 2 * len + 2)
      XCAR (tail) = data[i];
      else
      XCAR (tail) = Qnil;
      prev = tail;
    }

  /* If we couldn't fit all value elements into REUSE,
     cons up the rest of them and add them to the end of REUSE.  */
  if (i < 2 * len + 2)
    XCDR (prev) = Flist (2 * len + 2 - i, data + i);

  return reuse;
}


DEFUN ("store-match-data", Fstore_match_data, 1, 1, 0, /*
Set internal data on last search match from elements of LIST.
LIST should have been created by calling `match-data' previously.
*/
       (list))
{
  /* This function has been Mule-ized. */
  REGISTER int i;
  REGISTER Lisp_Object marker;
  int num_regs;
  int length;

  if (running_asynch_code)
    save_search_regs ();

  CONCHECK_LIST (list);

  /* Unless we find a marker with a buffer in LIST, assume that this
     match data came from a string.  */
  last_thing_searched = Qt;

  /* Allocate registers if they don't already exist.  */
  length = XINT (Flength (list)) / 2;
  num_regs = search_regs.num_regs;

  if (length > num_regs)
    {
      if (search_regs.num_regs == 0)
      {
        search_regs.start = xnew_array (regoff_t, length);
        search_regs.end   = xnew_array (regoff_t, length);
      }
      else
      {
        XREALLOC_ARRAY (search_regs.start, regoff_t, length);
        XREALLOC_ARRAY (search_regs.end,   regoff_t, length);
      }

      search_regs.num_regs = length;
    }

  for (i = 0; i < num_regs; i++)
    {
      marker = Fcar (list);
      if (NILP (marker))
      {
        search_regs.start[i] = -1;
        list = Fcdr (list);
      }
      else
      {
        if (MARKERP (marker))
          {
            if (XMARKER (marker)->buffer == 0)
            marker = Qzero;
            else
            XSETBUFFER (last_thing_searched, XMARKER (marker)->buffer);
          }

        CHECK_INT_COERCE_MARKER (marker);
        search_regs.start[i] = XINT (marker);
        list = Fcdr (list);

        marker = Fcar (list);
        if (MARKERP (marker) && XMARKER (marker)->buffer == 0)
          marker = Qzero;

        CHECK_INT_COERCE_MARKER (marker);
        search_regs.end[i] = XINT (marker);
      }
      list = Fcdr (list);
    }

  return Qnil;
}

/* If non-zero the match data have been saved in saved_search_regs
   during the execution of a sentinel or filter. */
static int search_regs_saved;
static struct re_registers saved_search_regs;

/* Called from Flooking_at, Fstring_match, search_buffer, Fstore_match_data
   if asynchronous code (filter or sentinel) is running. */
static void
save_search_regs (void)
{
  if (!search_regs_saved)
    {
      saved_search_regs.num_regs = search_regs.num_regs;
      saved_search_regs.start = search_regs.start;
      saved_search_regs.end = search_regs.end;
      search_regs.num_regs = 0;
      search_regs.start = 0;
      search_regs.end = 0;

      search_regs_saved = 1;
    }
}

/* Called upon exit from filters and sentinels. */
void
restore_match_data (void)
{
  if (search_regs_saved)
    {
      if (search_regs.num_regs > 0)
      {
        xfree (search_regs.start);
        xfree (search_regs.end);
      }
      search_regs.num_regs = saved_search_regs.num_regs;
      search_regs.start = saved_search_regs.start;
      search_regs.end = saved_search_regs.end;

      search_regs_saved = 0;
    }
}

/* Quote a string to inactivate reg-expr chars */

DEFUN ("regexp-quote", Fregexp_quote, 1, 1, 0, /*
Return a regexp string which matches exactly STRING and nothing else.
*/
       (string))
{
  REGISTER Bufbyte *in, *out, *end;
  REGISTER Bufbyte *temp;

  CHECK_STRING (string);

  temp = (Bufbyte *) alloca (XSTRING_LENGTH (string) * 2);

  /* Now copy the data into the new string, inserting escapes. */

  in = XSTRING_DATA (string);
  end = in + XSTRING_LENGTH (string);
  out = temp;

  while (in < end)
    {
      Emchar c = charptr_emchar (in);

      if (c == '[' || c == ']'
        || c == '*' || c == '.' || c == '\\'
        || c == '?' || c == '+'
        || c == '^' || c == '$')
      *out++ = '\\';
      out += set_charptr_emchar (out, c);
      INC_CHARPTR (in);
    }

  return make_string (temp, out - temp);
}

DEFUN ("set-word-regexp", Fset_word_regexp, 1, 1, 0, /*
Set the regexp to be used to match a word in regular-expression searching.
#### Not yet implemented.  Currently does nothing.
#### Do not use this yet.  Its calling interface is likely to change.
*/
       (regexp))
{
  return Qnil;
}


/************************************************************************/
/*                            initialization                            */
/************************************************************************/

void
syms_of_search (void)
{

  DEFERROR_STANDARD (Qsearch_failed, Qinvalid_operation);
  DEFERROR_STANDARD (Qinvalid_regexp, Qsyntax_error);

  DEFSUBR (Flooking_at);
  DEFSUBR (Fposix_looking_at);
  DEFSUBR (Fstring_match);
  DEFSUBR (Fposix_string_match);
  DEFSUBR (Fskip_chars_forward);
  DEFSUBR (Fskip_chars_backward);
  DEFSUBR (Fskip_syntax_forward);
  DEFSUBR (Fskip_syntax_backward);
  DEFSUBR (Fsearch_forward);
  DEFSUBR (Fsearch_backward);
  DEFSUBR (Fword_search_forward);
  DEFSUBR (Fword_search_backward);
  DEFSUBR (Fre_search_forward);
  DEFSUBR (Fre_search_backward);
  DEFSUBR (Fposix_search_forward);
  DEFSUBR (Fposix_search_backward);
  DEFSUBR (Freplace_match);
  DEFSUBR (Fmatch_beginning);
  DEFSUBR (Fmatch_end);
  DEFSUBR (Fmatch_data);
  DEFSUBR (Fstore_match_data);
  DEFSUBR (Fregexp_quote);
  DEFSUBR (Fset_word_regexp);
}

void
reinit_vars_of_search (void)
{
  int i;

  last_thing_searched = Qnil;
  staticpro_nodump (&last_thing_searched);

  for (i = 0; i < REGEXP_CACHE_SIZE; ++i)
    {
      searchbufs[i].buf.allocated = 100;
      searchbufs[i].buf.buffer = (unsigned char *) xmalloc (100);
      searchbufs[i].buf.fastmap = searchbufs[i].fastmap;
      searchbufs[i].regexp = Qnil;
      staticpro_nodump (&searchbufs[i].regexp);
      searchbufs[i].next = (i == REGEXP_CACHE_SIZE-1 ? 0 : &searchbufs[i+1]);
    }
  searchbuf_head = &searchbufs[0];
}

void
vars_of_search (void)
{
  reinit_vars_of_search ();

  DEFVAR_LISP ("forward-word-regexp", &Vforward_word_regexp /*
*Regular expression to be used in `forward-word'.
#### Not yet implemented.
*/ );
  Vforward_word_regexp = Qnil;

  DEFVAR_LISP ("backward-word-regexp", &Vbackward_word_regexp /*
*Regular expression to be used in `backward-word'.
#### Not yet implemented.
*/ );
  Vbackward_word_regexp = Qnil;
}

void
complex_vars_of_search (void)
{
  Vskip_chars_range_table = Fmake_range_table ();
  staticpro (&Vskip_chars_range_table);
}

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