143 lines
3.3 KiB
Plaintext
143 lines
3.3 KiB
Plaintext
/*
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* Copyright (C) 2021 Huawei Device Co., Ltd.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http:// www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { CustomMap } from './CustomMap'
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export class LruCache<K, V> {
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maxsize: number = 0
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size: number = 0;
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map: CustomMap<K, V> = new CustomMap<K, V>();
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constructor(maxsize: number) {
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this.trimToSize(-1)
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this.maxsize = maxsize
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this.size = 0;
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}
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// 添加缓存键值对
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put(key: K, value: V) {
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if (key == null || value == null) {
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throw new Error('key or value is invalid ');
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}
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let pre = this.map.get(key)
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if (pre == null) {
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this.size++
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}
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this.entryRemoved(key, pre, value)
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this.trimToSize(this.maxsize)
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}
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// 移除键为key的缓存
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remove(key: K): V | undefined {
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if (key == null) {
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throw new Error('key is null,checking the parameter');
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}
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let preValue = this.map.get(key)
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if (this.map.remove(key)) {
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this.size--
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}
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return preValue
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}
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// 获取键为key的value
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get(key: K): V | undefined {
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if (key == null) {
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throw new Error('key is null,checking the parameter');
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}
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let preValue = this.map.get(key)
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if (preValue != null) {
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this.entryRemoved(key, preValue, preValue)
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}
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return preValue
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}
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// 是否存在key
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has(key: K): boolean {
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return this.map.hasKey(key);
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}
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/*
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* 替换或删除对应key键的数据
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* evicted：是否删除
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* key：对应的键值key
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* preValue 对应key键的旧value值
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* value 对应key键的新value值
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*/
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entryRemoved(key: K, preValue: V | undefined, value: V | undefined) {
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if (preValue != null) {
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this.map.remove(key)
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}
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if (value != null) {
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this.map.put(key, value)
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}
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}
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// 移除较少使用的缓存数据
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trimToSize(tempsize: number) {
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while (true) {
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if (tempsize < 0) {
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this.map.clear()
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this.size = 0
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break
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}
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if (this.size <= tempsize || this.map.isEmpty()) {
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break
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}
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let delkey = this.map.getFirstKey()
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this.map.remove(delkey)
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this.size--
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}
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}
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// 缓存数据数量
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sizeLength(): number {
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return this.size
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}
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// 缓存数据最大值
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maxSize(): number {
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return this.maxsize
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}
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// 设置缓存数据量最大值
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resize(maxsize: number) {
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if (maxsize < 0) {
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throw new Error('maxsize <0 & maxsize invalid');
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}
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this.maxsize = maxsize
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this.trimToSize(maxsize)
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}
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// 清除缓存
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evicAll() {
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this.trimToSize(-1)
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}
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print(): string {
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let printResult = '';
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if (this.map.isEmpty()) {
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return printResult;
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}
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this.map.each((value, key, index) => {
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printResult += 'LruCache:key=' + key + 'value= ' + value;
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})
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return printResult;
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}
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foreachLruCache(fn: (value: V, key: K, map: Map<K, V>) => void) {
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this.map.each(fn);
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}
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} |