1 /*
2 * Dropbear - a SSH2 server
3 *
4 * Copyright (c) 2002,2003 Matt Johnston
5 * All rights reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE. */
24
25 #include "includes.h"
26 #include "dbutil.h"
27 #include "queue.h"
28
initqueue(struct Queue * queue)29 void initqueue(struct Queue* queue) {
30
31 queue->head = NULL;
32 queue->tail = NULL;
33 queue->count = 0;
34 }
35
isempty(struct Queue * queue)36 int isempty(struct Queue* queue) {
37
38 return (queue->head == NULL);
39 }
40
dequeue(struct Queue * queue)41 void* dequeue(struct Queue* queue) {
42
43 void* ret;
44 struct Link* oldhead;
45 dropbear_assert(!isempty(queue));
46
47 ret = queue->head->item;
48 oldhead = queue->head;
49
50 if (oldhead->link != NULL) {
51 queue->head = oldhead->link;
52 } else {
53 queue->head = NULL;
54 queue->tail = NULL;
55 TRACE(("empty queue dequeing"))
56 }
57
58 m_free(oldhead);
59 queue->count--;
60 return ret;
61 }
62
examine(struct Queue * queue)63 void *examine(struct Queue* queue) {
64
65 dropbear_assert(!isempty(queue));
66 return queue->head->item;
67 }
68
enqueue(struct Queue * queue,void * item)69 void enqueue(struct Queue* queue, void* item) {
70
71 struct Link* newlink;
72
73 TRACE(("enter enqueue"))
74 newlink = (struct Link*)m_malloc(sizeof(struct Link));
75
76 newlink->item = item;
77 newlink->link = NULL;
78
79 if (queue->tail != NULL) {
80 queue->tail->link = newlink;
81 }
82 queue->tail = newlink;
83
84 if (queue->head == NULL) {
85 queue->head = newlink;
86 }
87 queue->count++;
88 TRACE(("leave enqueue"))
89 }
90