| 1 | /* |
| 2 | Copyright (C) 1993-1998, 2001-2014 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 of the License, or |
| 7 | (at your option) 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. If not, see <http://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | /* This file implements the emacs_insque and emacs_remque functions, |
| 18 | clones of the insque and remque functions of BSD. They and all |
| 19 | their callers have been renamed to emacs_mumble to allow us to |
| 20 | include this file in the menu library on all systems. */ |
| 21 | |
| 22 | #include "XMenuInt.h" |
| 23 | |
| 24 | struct qelem { |
| 25 | struct qelem *q_forw; |
| 26 | struct qelem *q_back; |
| 27 | char q_data[1]; |
| 28 | }; |
| 29 | |
| 30 | /* Insert ELEM into a doubly-linked list, after PREV. */ |
| 31 | |
| 32 | void |
| 33 | emacs_insque (void *velem, void *vprev) |
| 34 | { |
| 35 | struct qelem *elem = velem; |
| 36 | struct qelem *prev = vprev; |
| 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 | void |
| 48 | emacs_remque (void *velem) |
| 49 | { |
| 50 | struct qelem *elem = velem; |
| 51 | struct qelem *next = elem->q_forw; |
| 52 | struct qelem *prev = elem->q_back; |
| 53 | if (next) |
| 54 | next->q_back = prev; |
| 55 | if (prev) |
| 56 | prev->q_forw = next; |
| 57 | } |