include/queue.h

   1 /*
   2  * Copyright (c) 2002-2004 MontaVista Software, Inc.
   3  *
   4  * All rights reserved.
   5  *
   6  * Author: Steven Dake (sdake@mvista.com)
   7  *
   8  * This software licensed under BSD license, the text of which follows:
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions are met:
  12  *
  13  * - Redistributions of source code must retain the above copyright notice,
  14  *   this list of conditions and the following disclaimer.
  15  * - Redistributions in binary form must reproduce the above copyright notice,
  16  *   this list of conditions and the following disclaimer in the documentation
  17  *   and/or other materials provided with the distribution.
  18  * - Neither the name of the MontaVista Software, Inc. nor the names of its
  19  *   contributors may be used to endorse or promote products derived from this
  20  *   software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  32  * THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34 #ifndef QUEUE_H_DEFINED
  35 #define QUEUE_H_DEFINED
  36
  37 #include <string.h>
  38 #include <pthread.h>
  39 #include "assert.h"
  40
  41 #ifdef OPENAIS_SOLARIS
  42 /* struct queue is already defined in sys/stream.h on Solaris */
  43 #define queue _queue
  44 #endif
  45 struct queue {
  46         int head;
  47         int tail;
  48         int used;
  49         int usedhw;
  50         int size;
  51         void *items;
  52         int size_per_item;
  53         int iterator;
  54         pthread_mutex_t mutex;
  55 };
  56
  57 static inline int queue_init (struct queue *queue, int queue_items, int size_per_item) {
  58         queue->head = 0;
  59         queue->tail = queue_items - 1;
  60         queue->used = 0;
  61         queue->usedhw = 0;
  62         queue->size = queue_items;
  63         queue->size_per_item = size_per_item;
  64
  65         queue->items = malloc (queue_items * size_per_item);
  66         if (queue->items == 0) {
  67                 return (-ENOMEM);
  68         }
  69         memset (queue->items, 0, queue_items * size_per_item);
  70         pthread_mutex_init (&queue->mutex, NULL);
  71         return (0);
  72 }
  73
  74 static inline int queue_reinit (struct queue *queue)
  75 {
  76         pthread_mutex_lock (&queue->mutex);
  77         queue->head = 0;
  78         queue->tail = queue->size - 1;
  79         queue->used = 0;
  80         queue->usedhw = 0;
  81
  82         memset (queue->items, 0, queue->size * queue->size_per_item);
  83         pthread_mutex_unlock (&queue->mutex);
  84         return (0);
  85 }
  86
  87 static inline void queue_free (struct queue *queue) {
  88         pthread_mutex_destroy (&queue->mutex);
  89         free (queue->items);
  90 }
  91
  92 static inline int queue_is_full (struct queue *queue) {
  93         int full;
  94
  95         pthread_mutex_lock (&queue->mutex);
  96         full = ((queue->size - 1) == queue->used);
  97         pthread_mutex_unlock (&queue->mutex);
  98         return (full);
  99 }
 100
 101 static inline int queue_is_empty (struct queue *queue) {
 102         int empty;
 103
 104         pthread_mutex_lock (&queue->mutex);
 105         empty = (queue->used == 0);
 106         pthread_mutex_unlock (&queue->mutex);
 107         return (empty);
 108 }
 109
 110 static inline void queue_item_add (struct queue *queue, void *item)
 111 {
 112         char *queue_item;
 113         int queue_position;
 114
 115         pthread_mutex_lock (&queue->mutex);
 116         queue_position = queue->head;
 117         queue_item = queue->items;
 118         queue_item += queue_position * queue->size_per_item;
 119         memcpy (queue_item, item, queue->size_per_item);
 120
 121         assert (queue->tail != queue->head);
 122
 123         queue->head = (queue->head + 1) % queue->size;
 124         queue->used++;
 125         if (queue->used > queue->usedhw) {
 126                 queue->usedhw = queue->used;
 127         }
 128         pthread_mutex_unlock (&queue->mutex);
 129 }
 130
 131 static inline void *queue_item_get (struct queue *queue)
 132 {
 133         char *queue_item;
 134         int queue_position;
 135
 136         pthread_mutex_lock (&queue->mutex);
 137         queue_position = (queue->tail + 1) % queue->size;
 138         queue_item = queue->items;
 139         queue_item += queue_position * queue->size_per_item;
 140         pthread_mutex_unlock (&queue->mutex);
 141         return ((void *)queue_item);
 142 }
 143
 144 static inline void queue_item_remove (struct queue *queue) {
 145         pthread_mutex_lock (&queue->mutex);
 146         queue->tail = (queue->tail + 1) % queue->size;
 147
 148         assert (queue->tail != queue->head);
 149
 150         queue->used--;
 151         assert (queue->used >= 0);
 152         pthread_mutex_unlock (&queue->mutex);
 153 }
 154
 155 static inline void queue_items_remove (struct queue *queue, int rel_count)
 156 {
 157         pthread_mutex_lock (&queue->mutex);
 158         queue->tail = (queue->tail + rel_count) % queue->size;
 159
 160         assert (queue->tail != queue->head);
 161
 162         queue->used -= rel_count;
 163         pthread_mutex_unlock (&queue->mutex);
 164 }
 165
 166
 167 static inline void queue_item_iterator_init (struct queue *queue)
 168 {
 169         pthread_mutex_lock (&queue->mutex);
 170         queue->iterator = (queue->tail + 1) % queue->size;
 171         pthread_mutex_unlock (&queue->mutex);
 172 }
 173
 174 static inline void *queue_item_iterator_get (struct queue *queue)
 175 {
 176         char *queue_item;
 177         int queue_position;
 178
 179         pthread_mutex_lock (&queue->mutex);
 180         queue_position = (queue->iterator) % queue->size;
 181         if (queue->iterator == queue->head) {
 182                 pthread_mutex_unlock (&queue->mutex);
 183                 return (0);
 184         }
 185         queue_item = queue->items;
 186         queue_item += queue_position * queue->size_per_item;
 187         pthread_mutex_unlock (&queue->mutex);
 188         return ((void *)queue_item);
 189 }
 190
 191 static inline int queue_item_iterator_next (struct queue *queue)
 192 {
 193         int next_res;
 194
 195         pthread_mutex_lock (&queue->mutex);
 196         queue->iterator = (queue->iterator + 1) % queue->size;
 197
 198         next_res = queue->iterator == queue->head;
 199         pthread_mutex_unlock (&queue->mutex);
 200         return (next_res);
 201 }
 202
 203 static inline void queue_avail (struct queue *queue, int *avail)
 204 {
 205         pthread_mutex_lock (&queue->mutex);
 206         *avail = queue->size - queue->used - 2;
 207         assert (*avail >= 0);
 208         pthread_mutex_unlock (&queue->mutex);
 209 }
 210
 211 static inline int queue_used (struct queue *queue) {
 212         int used;
 213
 214         pthread_mutex_lock (&queue->mutex);
 215         used = queue->used;
 216         pthread_mutex_unlock (&queue->mutex);
 217
 218         return (used);
 219 }
 220
 221 static inline int queue_usedhw (struct queue *queue) {
 222         int usedhw;
 223
 224         pthread_mutex_lock (&queue->mutex);
 225         usedhw = queue->usedhw;
 226         pthread_mutex_unlock (&queue->mutex);
 227
 228         return (usedhw);
 229 }
 230
 231 #endif /* QUEUE_H_DEFINED */