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97 lines
3.1 KiB
C
97 lines
3.1 KiB
C
/*
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* Copyright (C) 2019 BlueKitchen GmbH
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holders nor the names of
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* 4. Any redistribution, use, or modification is done solely for
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* personal benefit and not for any commercial purpose or for
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* monetary gain.
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*
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* THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
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* GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Please inquire about commercial licensing options at
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* contact@bluekitchen-gmbh.com
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*
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*/
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#define BTSTACK_FILE__ "btstack_linked_queue.c"
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#include "btstack_linked_queue.h"
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#include "btstack_debug.h"
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#include <stdlib.h>
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/**
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* @brief Tests if queue is empty
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* @return true if emtpy
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*/
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bool btstack_linked_queue_empty(btstack_linked_queue_t * queue){
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return queue->head == NULL;
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}
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/**
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* @brief Append item to queue
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* @param queue
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* @param item
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*/
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void btstack_linked_queue_enqueue(btstack_linked_queue_t * queue, btstack_linked_item_t * item){
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if (queue->head == NULL){
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// empty queue
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item->next = NULL;
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queue->head = item;
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queue->tail = item;
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} else {
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// non-empty
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item->next = NULL;
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queue->tail->next = item;
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queue->tail = item;
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}
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}
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/**
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* @brief Get first item from queue
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* @param queue
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* @return item or NULL if queue empty
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*/
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btstack_linked_item_t * btstack_linked_queue_first(btstack_linked_queue_t * queue){
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return queue->head;
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}
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/**
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* @brief Pop next item from queue
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* @param queue
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* @return item or NULL if queue empty
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*/
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btstack_linked_item_t * btstack_linked_queue_dequeue(btstack_linked_queue_t * queue){
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if (queue->head == NULL){
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return NULL;
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}
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btstack_linked_item_t * item = queue->head;
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queue->head = item->next;
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// reset tail if head becomes NULL
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if (queue->head == NULL){
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queue->tail = NULL;
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}
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return item;
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}
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