Jon Staab
66 lines
1.0 KiB
TypeScript
66 lines
1.0 KiB
TypeScript
export class LRUCache<T, U> {
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map = new Map<T, U>()
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keys: T[] = []
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constructor(readonly maxSize: number = Infinity) {}
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has(k: T) {
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return this.map.has(k)
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}
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get(k: T) {
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const v = this.map.get(k)
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if (v !== undefined) {
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this.keys.push(k as T)
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if (this.keys.length > this.maxSize * 2) {
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this.keys.splice(-this.maxSize)
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}
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}
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return v
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}
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set(k: T, v: U) {
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this.map.set(k, v)
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this.keys.push(k)
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if (this.map.size > this.maxSize) {
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this.map.delete(this.keys.shift() as T)
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}
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}
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}
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export function cached<T, V, Args extends any[]>({
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maxSize,
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getKey,
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getValue,
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}: {
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maxSize: number
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getKey: (args: Args) => T
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getValue: (args: Args) => V
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}) {
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const cache = new LRUCache<T, V>(maxSize)
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const get = (...args: Args) => {
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const k = getKey(args)
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let v = cache.get(k)
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if (!v) {
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v = getValue(args)
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cache.set(k, v)
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}
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return v
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}
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get.cache = cache
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get.getKey = getKey
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get.getValue = getValue
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return get
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}
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