57 lines
1.4 KiB
JavaScript
57 lines
1.4 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.lruQueue = lruQueue;
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// (c) 2018, Mariusz Nowak
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// SPDX-License-Identifier: ISC
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// Derived from https://github.com/medikoo/lru-queue
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function lruQueue(limit) {
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let size = 0;
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let base = 1;
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let queue = Object.create(null);
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let map = Object.create(null);
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let index = 0;
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const del = function (id) {
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const oldIndex = map[id];
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if (!oldIndex) return;
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delete queue[oldIndex];
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delete map[id];
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--size;
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if (base !== oldIndex) return;
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if (!size) {
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index = 0;
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base = 1;
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return;
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}
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while (!Object.prototype.hasOwnProperty.call(queue, ++base)) {/* empty */}
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};
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limit = Math.abs(limit);
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return {
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hit: function (id) {
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const oldIndex = map[id];
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const nuIndex = ++index;
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queue[nuIndex] = id;
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map[id] = nuIndex;
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if (!oldIndex) {
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++size;
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if (size <= limit) return undefined;
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id = queue[base];
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del(id);
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return id;
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}
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delete queue[oldIndex];
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if (base !== oldIndex) return undefined;
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while (!Object.prototype.hasOwnProperty.call(queue, ++base)) {/* empty */}
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return undefined;
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},
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delete: del,
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clear: function () {
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size = index = 0;
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base = 1;
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queue = Object.create(null);
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map = Object.create(null);
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}
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};
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} |