@phensley/cldr-utils/lib-es/lru.js

Utilities for cldr-engine packages

var DEFAULT_CAPACITY = 100;
/**
 * Cache evicts the least-recently-used key when capacity is exceeded.
 */
var LRU = /** @class */ (function () {
    function LRU(capacity) {
        if (capacity === void 0) { capacity = DEFAULT_CAPACITY; }
        this.storage = new Map();
        this.capacity = capacity;
        var root = {};
        root.next = root;
        root.prev = root;
        this.root = root;
    }
    LRU.prototype.size = function () {
        return this.storage.size;
    };
    LRU.prototype.get = function (key) {
        var n = this.storage.get(key);
        if (!n) {
            return undefined;
        }
        this.moveFront(n);
        return n.val;
    };
    LRU.prototype.set = function (key, val) {
        if (this.capacity === 0) {
            return;
        }
        var n = this.storage.get(key);
        // Key already exists, so replace its value and bump it
        // to the front. Size does not change.
        if (n) {
            n.val = val;
            this.moveFront(n);
            return;
        }
        // The lru is full, so reuse the oldest node to keep the
        // total node allocation stable.
        if (this.storage.size === this.capacity) {
            var old = this.root.prev;
            if (old !== undefined) {
                this.storage.delete(old.key);
                this.storage.set(key, old);
                old.key = key;
                old.val = val;
                this.moveFront(old);
            }
            return;
        }
        // The lru is not full, so allocate a new node.
        n = { key: key, val: val };
        this.storage.set(key, n);
        this.insert(n, this.root);
    };
    LRU.prototype.toString = function () {
        var res = '';
        var n = this.root.next;
        while (n && n !== this.root) {
            if (res.length > 0) {
                res += ' ';
            }
            res += n.key + "=" + n.val;
            n = n.next;
        }
        return res;
    };
    LRU.prototype.moveFront = function (n) {
        this.insert(this.remove(n), this.root);
    };
    LRU.prototype.insert = function (e, at) {
        var n = at.next;
        at.next = e;
        e.prev = at;
        e.next = n;
        if (n) {
            n.prev = e;
        }
        return e;
    };
    LRU.prototype.remove = function (n) {
        if (n.prev) {
            n.prev.next = n.next;
        }
        if (n.next) {
            n.next.prev = n.prev;
        }
        n.prev = undefined;
        n.next = undefined;
        return n;
    };
    return LRU;
}());
export { LRU };
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