oldXMenu/insque.c

   1 /* Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 2001, 2002, 2003,
   2                  2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   3
   4 This program is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 3, or (at your option)
   7 any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; see the file COPYING.  If not, write to
  16 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17 Boston, MA 02110-1301, USA.  */
  18
  19 /* This file implements the emacs_insque and emacs_remque functions,
  20    clones of the insque and remque functions of BSD.  They and all
  21    their callers have been renamed to emacs_mumble to allow us to
  22    include this file in the menu library on all systems.  */
  23
  24
  25 struct qelem {
  26   struct    qelem *q_forw;
  27   struct    qelem *q_back;
  28   char q_data[1];
  29 };
  30
  31 /* Insert ELEM into a doubly-linked list, after PREV.  */
  32
  33 void
  34 emacs_insque (elem, prev)
  35      struct qelem *elem, *prev;
  36 {
  37   struct qelem *next = prev->q_forw;
  38   prev->q_forw = elem;
  39   if (next)
  40     next->q_back = elem;
  41   elem->q_forw = next;
  42   elem->q_back = prev;
  43 }
  44
  45 /* Unlink ELEM from the doubly-linked list that it is in.  */
  46
  47 emacs_remque (elem)
  48      struct qelem *elem;
  49 {
  50   struct qelem *next = elem->q_forw;
  51   struct qelem *prev = elem->q_back;
  52   if (next)
  53     next->q_back = prev;
  54   if (prev)
  55     prev->q_forw = next;
  56 }
  57
  58 /* arch-tag: a8719d1a-5c3f-4bce-b36b-173106d36165
  59    (do not change this comment) */