/* * Copyright (c) 2020 * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <stddef.h> #ifndef AVFILTER_DNN_QUEUE_H#define AVFILTER_DNN_QUEUE_H /** * Linear double-ended data structure */typedef struct Queue Queue; /** * @brief Create a Queue instance. * It initializes the length of the Queue as 0. * * @return Pointer to the Queue * @retval NULL if allocation fails */Queue *ff_queue_create(void); /** * @brief Destroy the Queue instance. * It also frees all elements of the Queue. */void ff_queue_destroy(Queue *q); /** * @brief Return the length of the Queue */size_t ff_queue_size(Queue *q); /** * @brief Return a pointer to the data * at the head of the queue. * * @retval NULL if null pointer was passed * or queue is empty */void *ff_queue_peek_front(Queue *q); /** * @brief Return a pointer to the data at * the tail of the queue. * * @retval NULL if null pointer was passed * or queue is empty */void *ff_queue_peek_back(Queue *q); /** * @brief Add data to the head of the queue. * It increases the length of Queue by one. * * @param q pointer to the Queue. * @param v data to be added * @return The length of the Queue * @retval 0 if the pointer to queue is NULL * @retval -1 if new entry cannot be created */int ff_queue_push_front(Queue *q, void *v); /** * @brief Add data to the tail of the queue. * It increases the length of Queue by one. * * @param q pointer to the Queue * @param v data to be added * @return The length of the Queue * @retval 0 if the pointer to queue is NULL * @retval -1 if new entry cannot be created */int ff_queue_push_back(Queue *q, void *v); /** * @brief Remove and free first element from * the Queue. It shrinks the length of Queue * by one. * * @param q pointer to the Queue. * @return The value of first element as void. * If a null pointer or empty queue is passed, * it returns NULL */void *ff_queue_pop_front(Queue *q); /** * @brief Remove and free last element from * the Queue. It shrinks the length of Queue * by one. * * @param q pointer to the Queue. * @return The value of last element as void. * If a null pointer or empty queue is passed, * it returns NULL */void *ff_queue_pop_back(Queue *q); #endif