1 /* 2 * Copyright (c) 2020 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 #include <stddef.h> 22 23 #ifndef AVFILTER_DNN_QUEUE_H 24 #define AVFILTER_DNN_QUEUE_H 25 26 /** 27 * Linear double-ended data structure 28 */ 29 typedef struct Queue Queue; 30 31 /** 32 * @brief Create a Queue instance. 33 * It initializes the length of the Queue as 0. 34 * 35 * @return Pointer to the Queue 36 * @retval NULL if allocation fails 37 */ 38 Queue *ff_queue_create(void); 39 40 /** 41 * @brief Destroy the Queue instance. 42 * It also frees all elements of the Queue. 43 */ 44 void ff_queue_destroy(Queue *q); 45 46 /** 47 * @brief Return the length of the Queue 48 */ 49 size_t ff_queue_size(Queue *q); 50 51 /** 52 * @brief Return a pointer to the data 53 * at the head of the queue. 54 * 55 * @retval NULL if null pointer was passed 56 * or queue is empty 57 */ 58 void *ff_queue_peek_front(Queue *q); 59 60 /** 61 * @brief Return a pointer to the data at 62 * the tail of the queue. 63 * 64 * @retval NULL if null pointer was passed 65 * or queue is empty 66 */ 67 void *ff_queue_peek_back(Queue *q); 68 69 /** 70 * @brief Add data to the head of the queue. 71 * It increases the length of Queue by one. 72 * 73 * @param q pointer to the Queue. 74 * @param v data to be added 75 * @return The length of the Queue 76 * @retval 0 if the pointer to queue is NULL 77 * @retval -1 if new entry cannot be created 78 */ 79 int ff_queue_push_front(Queue *q, void *v); 80 81 /** 82 * @brief Add data to the tail of the queue. 83 * It increases the length of Queue by one. 84 * 85 * @param q pointer to the Queue 86 * @param v data to be added 87 * @return The length of the Queue 88 * @retval 0 if the pointer to queue is NULL 89 * @retval -1 if new entry cannot be created 90 */ 91 int ff_queue_push_back(Queue *q, void *v); 92 93 /** 94 * @brief Remove and free first element from 95 * the Queue. It shrinks the length of Queue 96 * by one. 97 * 98 * @param q pointer to the Queue. 99 * @return The value of first element as void. 100 * If a null pointer or empty queue is passed, 101 * it returns NULL 102 */ 103 void *ff_queue_pop_front(Queue *q); 104 105 /** 106 * @brief Remove and free last element from 107 * the Queue. It shrinks the length of Queue 108 * by one. 109 * 110 * @param q pointer to the Queue. 111 * @return The value of last element as void. 112 * If a null pointer or empty queue is passed, 113 * it returns NULL 114 */ 115 void *ff_queue_pop_back(Queue *q); 116 117 #endif 118