source: mainline/uspace/srv/net/structures/dynamic_fifo.h@ 21580dd

/*
 * Copyright (c) 2009 Lukas Mejdrech
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup net
 *  @{
 */

/** @file
 *  Dynamic first in first out positive integer queue.
 *  Possitive integer values only.
 */

#ifndef __NET_DYNAMIC_FIFO_H__
#define __NET_DYNAMIC_FIFO_H__

/** Type definition of the dynamic fifo queue.
 *  @see dyn_fifo
 */
typedef struct dyn_fifo dyn_fifo_t;

/** Type definition of the dynamic fifo queue pointer.
 *  @see dyn_fifo
 */
typedef dyn_fifo_t *    dyn_fifo_ref;

/** Dynamic first in first out positive integer queue.
 *  Possitive integer values only.
 *  The queue automatically resizes if needed.
 */
struct dyn_fifo{
        /** Stored item field.
         */
        int     *       items;
        /** Actual field size.
         */
        int             size;
        /** First item in the queue index.
         */
        int             head;
        /** Last item in the queue index.
         */
        int             tail;
        /** Consistency check magic value.
         */
        int             magic_value;
};

/** Initializes the dynamic queue.
 *  @param[in,out] fifo The dynamic queue.
 *  @param[in] size The initial queue size.
 *  @returns EOK on success.
 *  @returns EINVAL if the queue is not valid.
 *  @returns EBADMEM if the fifo parameter is NULL.
 *  @returns ENOMEM if there is not enough memory left.
 */
int     dyn_fifo_initialize( dyn_fifo_ref fifo, int size );

/** Appends a new item to the queue end.
 *  @param[in,out] fifo The dynamic queue.
 *  @param[in] value The new item value. Should be positive.
 *  @param[in] max_size The maximum queue size. The queue is not resized beyound this limit. May be zero or negative (<=0) to indicate no limit.
 *  @returns EOK on success.
 *  @returns EINVAL if the queue is not valid.
 *  @returns ENOMEM if there is not enough memory left.
 */
int     dyn_fifo_push( dyn_fifo_ref fifo, int value, int max_size );

/** Returns and excludes the first item in the queue.
 *  @param[in,out] fifo The dynamic queue.
 *  @returns Value of the first item in the queue.
 *  @returns EINVAL if the queue is not valid.
 *  @returns ENOENT if the queue is empty.
 */
int     dyn_fifo_pop( dyn_fifo_ref fifo );

/** Returns and keeps the first item in the queue.
 *  @param[in,out] fifo The dynamic queue.
 *  @returns Value of the first item in the queue.
 *  @returns EINVAL if the queue is not valid.
 *  @returns ENOENT if the queue is empty.
 */
int     dyn_fifo_value( dyn_fifo_ref fifo );

/** Clears and destroys the queue.
 *  @param[in,out] fifo The dynamic queue.
 *  @returns EOK on success.
 *  @returns EINVAL if the queue is not valid.
 */
int dyn_fifo_destroy( dyn_fifo_ref fifo );

#endif

/** @}
 */