/* * SPDX-FileCopyrightText: 2015-2022 The Apache Software Foundation (ASF) * * SPDX-License-Identifier: Apache-2.0 * * SPDX-FileContributor: 2019-2022 Espressif Systems (Shanghai) CO LTD */ /* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ #ifndef _QUEUE_H_ #define _QUEUE_H_ /* The common BSD linked list queue macros are already defined here for ESP-IDF */ #include #ifdef __cplusplus extern "C" { #endif /* * This file defines circular queues. The other types of data structures: * singly-linked lists, singly-linked tail queues, lists and tail queues * are used from sys/queue.h * * A singly-linked list is headed by a single forward pointer. The elements * are singly linked for minimum space and pointer manipulation overhead at * the expense of O(n) removal for arbitrary elements. New elements can be * added to the list after an existing element or at the head of the list. * Elements being removed from the head of the list should use the explicit * macro for this purpose for optimum efficiency. A singly-linked list may * only be traversed in the forward direction. Singly-linked lists are ideal * for applications with large datasets and few or no removals or for * implementing a LIFO queue. * * A singly-linked tail queue is headed by a pair of pointers, one to the * head of the list and the other to the tail of the list. The elements are * singly linked for minimum space and pointer manipulation overhead at the * expense of O(n) removal for arbitrary elements. New elements can be added * to the list after an existing element, at the head of the list, or at the * end of the list. Elements being removed from the head of the tail queue * should use the explicit macro for this purpose for optimum efficiency. * A singly-linked tail queue may only be traversed in the forward direction. * Singly-linked tail queues are ideal for applications with large datasets * and few or no removals or for implementing a FIFO queue. * * A list is headed by a single forward pointer (or an array of forward * pointers for a hash table header). The elements are doubly linked * so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before * or after an existing element or at the head of the list. A list * may only be traversed in the forward direction. * * A tail queue is headed by a pair of pointers, one to the head of the * list and the other to the tail of the list. The elements are doubly * linked so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before or * after an existing element, at the head of the list, or at the end of * the list. A tail queue may be traversed in either direction. * * A circle queue is headed by a pair of pointers, one to the head of the * list and the other to the tail of the list. The elements are doubly * linked so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before or after * an existing element, at the head of the list, or at the end of the list. * A circle queue may be traversed in either direction, but has a more * complex end of list detection. * * For details on the use of these macros, see the queue(3) manual page. * * * SLIST LIST STAILQ TAILQ CIRCLEQ * _HEAD + + + + + * _HEAD_INITIALIZER + + + + + * _ENTRY + + + + + * _INIT + + + + + * _EMPTY + + + + + * _FIRST + + + + + * _NEXT + + + + + * _PREV - - - + + * _LAST - - + + + * _FOREACH + + + + + * _FOREACH_REVERSE - - - + + * _INSERT_HEAD + + + + + * _INSERT_BEFORE - + - + + * _INSERT_AFTER + + + + + * _INSERT_TAIL - - + + + * _REMOVE_HEAD + - + - - * _REMOVE + + + + + * */ /* * Circular queue declarations. */ #define CIRCLEQ_HEAD(name, type) \ struct name { \ struct type *cqh_first; /* first element */ \ struct type *cqh_last; /* last element */ \ } #define CIRCLEQ_HEAD_INITIALIZER(head) \ { (void *)&(head), (void *)&(head) } #define CIRCLEQ_ENTRY(type) \ struct { \ struct type *cqe_next; /* next element */ \ struct type *cqe_prev; /* previous element */ \ } /* * Circular queue functions. */ #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) #define CIRCLEQ_FIRST(head) ((head)->cqh_first) #define CIRCLEQ_FOREACH(var, head, field) \ for ((var) = CIRCLEQ_FIRST((head)); \ (var) != (void *)(head) || ((var) = NULL); \ (var) = CIRCLEQ_NEXT((var), field)) #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ for ((var) = CIRCLEQ_LAST((head)); \ (var) != (void *)(head) || ((var) = NULL); \ (var) = CIRCLEQ_PREV((var), field)) #define CIRCLEQ_INIT(head) do { \ CIRCLEQ_FIRST((head)) = (void *)(head); \ CIRCLEQ_LAST((head)) = (void *)(head); \ } while (0) #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \ CIRCLEQ_PREV((elm), field) = (listelm); \ if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \ CIRCLEQ_LAST((head)) = (elm); \ else \ CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\ CIRCLEQ_NEXT((listelm), field) = (elm); \ } while (0) #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ CIRCLEQ_NEXT((elm), field) = (listelm); \ CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \ if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \ CIRCLEQ_FIRST((head)) = (elm); \ else \ CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\ CIRCLEQ_PREV((listelm), field) = (elm); \ } while (0) #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \ CIRCLEQ_PREV((elm), field) = (void *)(head); \ if (CIRCLEQ_LAST((head)) == (void *)(head)) \ CIRCLEQ_LAST((head)) = (elm); \ else \ CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \ CIRCLEQ_FIRST((head)) = (elm); \ } while (0) #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ CIRCLEQ_NEXT((elm), field) = (void *)(head); \ CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \ if (CIRCLEQ_FIRST((head)) == (void *)(head)) \ CIRCLEQ_FIRST((head)) = (elm); \ else \ CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \ CIRCLEQ_LAST((head)) = (elm); \ } while (0) #define CIRCLEQ_LAST(head) ((head)->cqh_last) #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) #define CIRCLEQ_REMOVE(head, elm, field) do { \ if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \ CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \ else \ CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \ CIRCLEQ_PREV((elm), field); \ if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \ CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \ else \ CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \ CIRCLEQ_NEXT((elm), field); \ } while (0) #ifdef __cplusplus } #endif #endif /* !_SYS_QUEUE_H_ */