1/*--------------------------------------------------------------------------
2Copyright (c) 2010-2011, 2013, The Linux Foundation. All rights reserved.
3
4Redistribution and use in source and binary forms, with or without
5modification, are permitted provided that the following conditions are met:
6    * Redistributions of source code must retain the above copyright
7      notice, this list of conditions and the following disclaimer.
8    * Redistributions in binary form must reproduce the above copyright
9      notice, this list of conditions and the following disclaimer in the
10      documentation and/or other materials provided with the distribution.
11    * Neither the name of The Linux Foundation nor
12      the names of its contributors may be used to endorse or promote
13      products derived from this software without specific prior written
14      permission.
15
16THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19NON-INFRINGEMENT ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
20CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
25OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
26ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27--------------------------------------------------------------------------*/
28/*
29   Queue with Linked list
30 */
31
32#include "queue.h"
33#include <stdio.h>
34#include <stdlib.h>
35
36
37typedef struct Node {
38    void *element;
39    struct Node *next;
40} Node;
41
42struct Queue {
43    Node *head;
44    Node *tail;
45    int  current_size;
46};
47
48Queue *alloc_queue()
49{
50    Queue *q = (Queue *) malloc(sizeof(Queue));
51
52    if (q) {
53        q->head = q->tail = NULL;
54        q->current_size = 0;
55    }
56
57    return q;
58}
59
60void free_queue(Queue *q)
61{
62    while (q->current_size) {
63        pop(q);
64    }
65}
66
67void free_queue_and_qelement(Queue *q)
68{
69    while (q->current_size) {
70        void *element = pop(q);
71
72        if (element)
73            free(element);
74    }
75}
76
77int push(Queue *q, void * element)
78{
79    Node *new_node = (Node *) malloc(sizeof(Node));
80
81    if (new_node == NULL)
82        return -1;
83
84    new_node->element = element;
85    new_node->next = NULL;
86
87    if (q->current_size == 0) {
88        q->head = new_node;
89    } else {
90        q->tail->next = new_node;
91    }
92
93    q->tail = new_node;
94    q->current_size++;
95
96    return 0;
97}
98
99void *pop(Queue *q)
100{
101    Node *temp;
102    void *element;
103
104    if (q->current_size == 0)
105        return NULL;
106
107    temp = q->head;
108    element = temp->element;
109
110    if (q->current_size == 1) {
111        q->head = q->tail = NULL;
112    } else {
113        q->head = q->head->next;
114    }
115
116    free(temp);
117    q->current_size--;
118    return element;
119}
120
121