| /* | |
| * 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 | |
| */ | |
| /** | |
| * 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); | |