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      1 /* Copyright (c) 2012, The Linux Foundation. All rights reserved.
      2  *
      3  * Redistribution and use in source and binary forms, with or without
      4  * modification, are permitted provided that the following conditions are
      5  * 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
      9  *       copyright notice, this list of conditions and the following
     10  *       disclaimer in the documentation and/or other materials provided
     11  *       with the distribution.
     12  *     * Neither the name of The Linux Foundation nor the names of its
     13  *       contributors may be used to endorse or promote products derived
     14  *       from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
     23  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     24  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     25  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
     26  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  *
     28  */
     29 
     30 #include "cam_list.h"
     31 
     32 typedef struct {
     33     struct cam_list list;
     34     void *data;
     35 } cam_node_t;
     36 
     37 typedef struct {
     38     cam_node_t head; /* dummy head */
     39     uint32_t size;
     40     pthread_mutex_t lock;
     41 } cam_queue_t;
     42 
     43 static inline int32_t cam_queue_init(cam_queue_t *queue)
     44 {
     45     pthread_mutex_init(&queue->lock, NULL);
     46     cam_list_init(&queue->head.list);
     47     queue->size = 0;
     48     return 0;
     49 }
     50 
     51 static inline int32_t cam_queue_enq(cam_queue_t *queue, void *data)
     52 {
     53     cam_node_t *node =
     54         (cam_node_t *)malloc(sizeof(cam_node_t));
     55     if (NULL == node) {
     56         return -1;
     57     }
     58 
     59     memset(node, 0, sizeof(cam_node_t));
     60     node->data = data;
     61 
     62     pthread_mutex_lock(&queue->lock);
     63     cam_list_add_tail_node(&node->list, &queue->head.list);
     64     queue->size++;
     65     pthread_mutex_unlock(&queue->lock);
     66 
     67     return 0;
     68 }
     69 
     70 static inline void *cam_queue_deq(cam_queue_t *queue)
     71 {
     72     cam_node_t *node = NULL;
     73     void *data = NULL;
     74     struct cam_list *head = NULL;
     75     struct cam_list *pos = NULL;
     76 
     77     pthread_mutex_lock(&queue->lock);
     78     head = &queue->head.list;
     79     pos = head->next;
     80     if (pos != head) {
     81         node = member_of(pos, cam_node_t, list);
     82         cam_list_del_node(&node->list);
     83         queue->size--;
     84     }
     85     pthread_mutex_unlock(&queue->lock);
     86 
     87     if (NULL != node) {
     88         data = node->data;
     89         free(node);
     90     }
     91 
     92     return data;
     93 }
     94 
     95 static inline int32_t cam_queue_flush(cam_queue_t *queue)
     96 {
     97     cam_node_t *node = NULL;
     98     struct cam_list *head = NULL;
     99     struct cam_list *pos = NULL;
    100 
    101     pthread_mutex_lock(&queue->lock);
    102     head = &queue->head.list;
    103     pos = head->next;
    104 
    105     while(pos != head) {
    106         node = member_of(pos, cam_node_t, list);
    107         pos = pos->next;
    108         cam_list_del_node(&node->list);
    109         queue->size--;
    110 
    111         /* TODO later to consider ptr inside data */
    112         /* for now we only assume there is no ptr inside data
    113          * so we free data directly */
    114         if (NULL != node->data) {
    115             free(node->data);
    116         }
    117         free(node);
    118 
    119     }
    120     queue->size = 0;
    121     pthread_mutex_unlock(&queue->lock);
    122     return 0;
    123 }
    124 
    125 static inline int32_t cam_queue_deinit(cam_queue_t *queue)
    126 {
    127     cam_queue_flush(queue);
    128     pthread_mutex_destroy(&queue->lock);
    129     return 0;
    130 }
    131