text: /* parens.c -- Implementation of matching parentheses feature. */
  
  /* Copyright (C) 1987, 1989, 1992 Free Software Foundation, Inc.
  
     This file is part of the GNU Readline Library, a library for
     reading lines of text with interactive input and history editing.
  
     The GNU Readline Library 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.
  
     The GNU Readline Library 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.
  
     The GNU General Public License is often shipped with GNU software, and
     is generally kept in a file called COPYING or LICENSE.  If you do not
     have a copy of the license, write to the Free Software Foundation,
     59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  #define READLINE_LIBRARY
  
  #include "rlconf.h"
  
  #if defined (HAVE_CONFIG_H)
  #  include <config.h>
  #endif
  
  #include <stdio.h>
  #include <sys/types.h>
  
  #if defined (FD_SET) && !defined (HAVE_SELECT)
  #  define HAVE_SELECT
  #endif
  
  #if defined (HAVE_SELECT)
  #  include <sys/time.h>
  #endif /* HAVE_SELECT */
  #if defined (HAVE_SYS_SELECT_H)
  #  include <sys/select.h>
  #endif
  
  #if defined (HAVE_STRING_H)
  #  include <string.h>
  #else /* !HAVE_STRING_H */
  #  include <strings.h>
  #endif /* !HAVE_STRING_H */
  
  #if !defined (strchr) && !defined (__STDC__)
  extern char *strchr (), *strrchr ();
  #endif /* !strchr && !__STDC__ */
  
  #include "readline.h"
  #include "rlprivate.h"
  
  static int find_matching_open __P((char *, int, int));
  
  /* Non-zero means try to blink the matching open parenthesis when the
     close parenthesis is inserted. */
  #if defined (HAVE_SELECT)
  int rl_blink_matching_paren = 1;
  #else /* !HAVE_SELECT */
  int rl_blink_matching_paren = 0;
  #endif /* !HAVE_SELECT */
  
  static int _paren_blink_usec = 500000;
  
  /* Change emacs_standard_keymap to have bindings for paren matching when
     ON_OR_OFF is 1, change them back to self_insert when ON_OR_OFF == 0. */
  void
  _rl_enable_paren_matching (on_or_off)
       int on_or_off;
  {
    if (on_or_off)
      {	/* ([{ */
        rl_bind_key_in_map (')', rl_insert_close, emacs_standard_keymap);
        rl_bind_key_in_map (']', rl_insert_close, emacs_standard_keymap);
        rl_bind_key_in_map ('}', rl_insert_close, emacs_standard_keymap);
      }
    else
      {	/* ([{ */
        rl_bind_key_in_map (')', rl_insert, emacs_standard_keymap);
        rl_bind_key_in_map (']', rl_insert, emacs_standard_keymap);
        rl_bind_key_in_map ('}', rl_insert, emacs_standard_keymap);
      }
  }
  
  int
  rl_set_paren_blink_timeout (u)
       int u;
  {
    int o;
  
    o = _paren_blink_usec;
    if (u > 0)
      _paren_blink_usec = u;
    return (o);
  }
  
  int
  rl_insert_close (count, invoking_key)
       int count, invoking_key;
  {
    if (rl_explicit_arg || !rl_blink_matching_paren)
      rl_insert (count, invoking_key);
    else
      {
  #if defined (HAVE_SELECT)
        int orig_point, match_point, ready;
        struct timeval timer;
        fd_set readfds;
  
        rl_insert (1, invoking_key);
        (*rl_redisplay_function) ();
        match_point =
  	find_matching_open (rl_line_buffer, rl_point - 2, invoking_key);
  
        /* Emacs might message or ring the bell here, but I don't. */
        if (match_point < 0)
  	return -1;
  
        FD_ZERO (&readfds);
        FD_SET (fileno (rl_instream), &readfds);
        timer.tv_sec = 0;
        timer.tv_usec = _paren_blink_usec;
  
        orig_point = rl_point;
        rl_point = match_point;
        (*rl_redisplay_function) ();
        ready = select (1, &readfds, (fd_set *)NULL, (fd_set *)NULL, &timer);
        rl_point = orig_point;
  #else /* !HAVE_SELECT */
        rl_insert (count, invoking_key);
  #endif /* !HAVE_SELECT */
      }
    return 0;
  }
  
  static int
  find_matching_open (string, from, closer)
       char *string;
       int from, closer;
  {
    register int i;
    int opener, level, delimiter;
  
    switch (closer)
      {
      case ']': opener = '['; break;
      case '}': opener = '{'; break;
      case ')': opener = '('; break;
      default:
        return (-1);
      }
  
    level = 1;			/* The closer passed in counts as 1. */
    delimiter = 0;		/* Delimited state unknown. */
  
    for (i = from; i > -1; i--)
      {
        if (delimiter && (string[i] == delimiter))
  	delimiter = 0;
        else if (rl_basic_quote_characters && strchr (rl_basic_quote_characters, string[i]))
  	delimiter = string[i];
        else if (!delimiter && (string[i] == closer))
  	level++;
        else if (!delimiter && (string[i] == opener))
  	level--;
  
        if (!level)
  	break;
      }
    return (i);
  }
  