summaryrefslogtreecommitdiff
path: root/oldXMenu/insque.c
blob: 2395e4ea2d3b365b2d2af6d8520bc31746a9ee87 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
/* Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.  */

/* This file implements the emacs_insque and emacs_remque functions,
   copies of the insque and remque functions of BSD.  They and all
   their callers have been renamed to emacs_mumble to allow us to
   include this file in the menu library on all systems.  */


struct qelem {
  struct    qelem *q_forw;
  struct    qelem *q_back;
  char q_data[1];
};

/* Insert ELEM into a doubly-linked list, after PREV.  */

void
emacs_insque (elem, prev)
     struct qelem *elem, *prev;
{
  struct qelem *next = prev->q_forw;
  prev->q_forw = elem;
  if (next)
    next->q_back = elem;
  elem->q_forw = next;
  elem->q_back = prev;
}

/* Unlink ELEM from the doubly-linked list that it is in.  */

emacs_remque (elem)
     struct qelem *elem;
{
  struct qelem *next = elem->q_forw;
  struct qelem *prev = elem->q_back;
  if (next)
    next->q_back = prev;
  if (prev)
    prev->q_forw = next;
}

/* arch-tag: a8719d1a-5c3f-4bce-b36b-173106d36165
   (do not change this comment) */