1: /* Copyright (C) 1992, 1995, 1996, 2006 Free Software Foundation, Inc.
    2:    This file is part of the GNU C Library.
    3: 
    4:    The GNU C Library is free software; you can redistribute it and/or
    5:    modify it under the terms of the GNU Lesser General Public
    6:    License as published by the Free Software Foundation; either
    7:    version 2.1 of the License, or (at your option) any later version.
    8: 
    9:    The GNU C Library 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 GNU
   12:    Lesser General Public License for more details.
   13: 
   14:    You should have received a copy of the GNU Lesser General Public
   15:    License along with the GNU C Library; if not, write to the Free
   16:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   17:    02111-1307 USA.  */
   18: 
   19: #include <stddef.h>
   20: #include <search.h>
   21: 
   22: /* Insert ELEM into a doubly-linked list, after PREV.  */
   23: 
   24: void
   25: insque (void *elem, void *prev)
   26: {
   27:   if (prev == NULL)
   28:     {
   29:       ((struct qelem *) elem)->q_forw = NULL;
   30:       ((struct qelem *) elem)->q_back = NULL;
   31:     }
   32:   else
   33:     {
   34:       struct qelem *next = ((struct qelem *) prev)->q_forw;
   35:       ((struct qelem *) prev)->q_forw = (struct qelem *) elem;
   36:       if (next != NULL)
   37:         next->q_back = (struct qelem *) elem;
   38:       ((struct qelem *) elem)->q_forw = next;
   39:       ((struct qelem *) elem)->q_back = (struct qelem *) prev;
   40:     }
   41: }
   42: 
   43: /* Unlink ELEM from the doubly-linked list that it is in.  */
   44: 
   45: void
   46: remque (void *elem)
   47: {
   48:   struct qelem *next = ((struct qelem *) elem)->q_forw;
   49:   struct qelem *prev = ((struct qelem *) elem)->q_back;
   50:   if (next != NULL)
   51:     next->q_back = prev;
   52:   if (prev != NULL)
   53:     prev->q_forw = (struct qelem *) next;
   54: }