| /* |
| * 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 |
| */ |
| |
| #ifndef AVFILTER_DNN_SAFE_QUEUE_H |
| #define AVFILTER_DNN_SAFE_QUEUE_H |
| |
| /** |
| * Double-ended queue with mutex locks ensuring |
| * data consistency while multithreading. |
| */ |
| typedef struct SafeQueue SafeQueue; |
| |
| /** |
| * @brief Create and initialize a SafeQueue instance. |
| * |
| * @return Pointer to the SafeQueue |
| * @retval NULL if initialization fails |
| */ |
| SafeQueue *ff_safe_queue_create(void); |
| |
| /** |
| * @brief Destroy the SafeQueue instance. |
| * It also frees all elements of the queue, |
| * destroys the mutex and condition variable. |
| */ |
| void ff_safe_queue_destroy(SafeQueue *sq); |
| |
| /** |
| * @brief Return the length of the SafeQueue |
| */ |
| size_t ff_safe_queue_size(SafeQueue *sq); |
| |
| /** |
| * @brief Add data to the head of queue in the |
| * SafeQueue after locking mutex. After adding |
| * the data, it signals the condition variable |
| * and unlocks the mutex. It increases the length |
| * of queue in the SafeQueue by one. |
| * |
| * @param sq pointer to the SafeQueue |
| * @param v data to be added |
| * @return The length of the queue |
| * @retval 0 if the queue is not initialized |
| * @retval -1 if new entry cannot be created |
| */ |
| int ff_safe_queue_push_front(SafeQueue *sq, void *v); |
| |
| /** |
| * @brief Add data to the tail of queue in the |
| * SafeQueue after locking mutex. After adding |
| * the data, it signals the condition variable |
| * and unlocks the mutex. It increases the length |
| * of queue in the SafeQueue by one. |
| * |
| * @param sq pointer to the SafeQueue |
| * @param v data to be added |
| * @return The length of the queue |
| * @retval 0 if the queue is not initialized |
| * @retval -1 if new entry cannot be created |
| */ |
| int ff_safe_queue_push_back(SafeQueue *sq, void *v); |
| |
| /** |
| * @brief Remove and free first element from |
| * the queue in SafeQueue. Before removing, it |
| * waits for the condition variable to signal and |
| * acquires the mutex. Finally, it signals the |
| * condition and unlocks the mutex. |
| * It shrinks the length of queue in the SafeQueue |
| * by one. |
| * |
| * @param sq pointer to the SafeQueue. |
| * @return The value of first element as void. |
| * If a null pointer or empty queue is passed, |
| * it returns NULL |
| */ |
| void *ff_safe_queue_pop_front(SafeQueue *sq); |
| |
| #endif |