LinkedListBase.cpp

00001 /*
00002  * Copyright (c) 2018-2019, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #include "LinkedList.h"
00019 #include "LinkEntry.h"
00020 #include "mbed_assert.h"
00021 
00022 LinkedListBase::LinkedListBase(): _head(0), _tail(0)
00023 {
00024 
00025 }
00026 
00027 LinkedListBase::~LinkedListBase()
00028 {
00029 
00030 }
00031 
00032 LinkEntry *LinkedListBase::head()
00033 {
00034     return _head;
00035 }
00036 
00037 void LinkedListBase::enqueue(LinkEntry *entry)
00038 {
00039     entry->_next = NULL;
00040     if (_tail == NULL) {
00041         _head = entry;
00042     } else {
00043         _tail->_next = entry;
00044     }
00045     _tail = entry;
00046 }
00047 
00048 LinkEntry *LinkedListBase::dequeue()
00049 {
00050     if (_head == NULL) {
00051         return NULL;
00052     }
00053     if (_head->_next == NULL) {
00054         _tail = NULL;
00055     }
00056     LinkEntry *entry = _head;
00057     _head = _head->_next;
00058     entry->_next = NULL;
00059     return entry;
00060 }
00061 
00062 void LinkedListBase::remove(LinkEntry *entry)
00063 {
00064     LinkEntry *prev = NULL;
00065     LinkEntry *cur = _head;
00066     while (cur != entry) {
00067         if (cur == NULL) {
00068             // Element is not in the list
00069             return;
00070         }
00071         prev = cur;
00072         cur = cur->_next;
00073     }
00074 
00075     if (prev != NULL) {
00076         prev->_next = entry->_next;
00077     }
00078     if (entry == _head) {
00079         _head = entry->_next;
00080     }
00081     if (entry == _tail) {
00082         _tail = prev;
00083     }
00084     entry->_next = NULL;
00085 }