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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const SortableSet = require("./SortableSet");
/**
* @template T
* @template K
* Multi layer bucket sorted set
* Supports adding non-existing items (DO NOT ADD ITEM TWICE)
* Supports removing exiting items (DO NOT REMOVE ITEM NOT IN SET)
* Supports popping the first items according to defined order
* Supports iterating all items without order
* Supports updating an item in an efficient way
* Supports size property, which is the number of items
* Items are lazy partially sorted when needed
*/
class LazyBucketSortedSet {
/**
* @param {function(T): K} getKey function to get key from item
* @param {function(K, K): number} comparator comparator to sort keys
* @param {...((function(T): any) | (function(any, any): number))} args more pairs of getKey and comparator plus optional final comparator for the last layer
*/
constructor(getKey, comparator, ...args) {
this._getKey = getKey;
this._innerArgs = args;
this._leaf = args.length <= 1;
this._keys = new SortableSet(undefined, comparator);
/** @type {Map<K, LazyBucketSortedSet<T, any> | SortableSet<T>>} */
this._map = new Map();
this._unsortedItems = new Set();
this.size = 0;
}
/**
* @param {T} item an item
* @returns {void}
*/
add(item) {
this.size++;
this._unsortedItems.add(item);
}
/**
* @param {K} key key of item
* @param {T} item the item
* @returns {void}
*/
_addInternal(key, item) {
let entry = this._map.get(key);
if (entry === undefined) {
entry = this._leaf
? new SortableSet(undefined, this._innerArgs[0])
: new /** @type {any} */ (LazyBucketSortedSet)(...this._innerArgs);
this._keys.add(key);
this._map.set(key, entry);
}
entry.add(item);
}
/**
* @param {T} item an item
* @returns {void}
*/
delete(item) {
this.size--;
if (this._unsortedItems.has(item)) {
this._unsortedItems.delete(item);
return;
}
const key = this._getKey(item);
const entry = this._map.get(key);
entry.delete(item);
if (entry.size === 0) {
this._deleteKey(key);
}
}
/**
* @param {K} key key to be removed
* @returns {void}
*/
_deleteKey(key) {
this._keys.delete(key);
this._map.delete(key);
}
/**
* @returns {T | undefined} an item
*/
popFirst() {
if (this.size === 0) return undefined;
this.size--;
if (this._unsortedItems.size > 0) {
for (const item of this._unsortedItems) {
const key = this._getKey(item);
this._addInternal(key, item);
}
this._unsortedItems.clear();
}
this._keys.sort();
const key = this._keys.values().next().value;
const entry = this._map.get(key);
if (this._leaf) {
const leafEntry = /** @type {SortableSet<T>} */ (entry);
leafEntry.sort();
const item = leafEntry.values().next().value;
leafEntry.delete(item);
if (leafEntry.size === 0) {
this._deleteKey(key);
}
return item;
} else {
const nodeEntry = /** @type {LazyBucketSortedSet<T, any>} */ (entry);
const item = nodeEntry.popFirst();
if (nodeEntry.size === 0) {
this._deleteKey(key);
}
return item;
}
}
/**
* @param {T} item to be updated item
* @returns {function(true=): void} finish update
*/
startUpdate(item) {
if (this._unsortedItems.has(item)) {
return remove => {
if (remove) {
this._unsortedItems.delete(item);
this.size--;
return;
}
};
}
const key = this._getKey(item);
if (this._leaf) {
const oldEntry = /** @type {SortableSet<T>} */ (this._map.get(key));
return remove => {
if (remove) {
this.size--;
oldEntry.delete(item);
if (oldEntry.size === 0) {
this._deleteKey(key);
}
return;
}
const newKey = this._getKey(item);
if (key === newKey) {
// This flags the sortable set as unordered
oldEntry.add(item);
} else {
oldEntry.delete(item);
if (oldEntry.size === 0) {
this._deleteKey(key);
}
this._addInternal(newKey, item);
}
};
} else {
const oldEntry = /** @type {LazyBucketSortedSet<T, any>} */ (this._map.get(
key
));
const finishUpdate = oldEntry.startUpdate(item);
return remove => {
if (remove) {
this.size--;
finishUpdate(true);
if (oldEntry.size === 0) {
this._deleteKey(key);
}
return;
}
const newKey = this._getKey(item);
if (key === newKey) {
finishUpdate();
} else {
finishUpdate(true);
if (oldEntry.size === 0) {
this._deleteKey(key);
}
this._addInternal(newKey, item);
}
};
}
}
/**
* @param {Iterator<T>[]} iterators list of iterators to append to
* @returns {void}
*/
_appendIterators(iterators) {
if (this._unsortedItems.size > 0)
iterators.push(this._unsortedItems[Symbol.iterator]());
for (const key of this._keys) {
const entry = this._map.get(key);
if (this._leaf) {
const leafEntry = /** @type {SortableSet<T>} */ (entry);
const iterator = leafEntry[Symbol.iterator]();
iterators.push(iterator);
} else {
const nodeEntry = /** @type {LazyBucketSortedSet<T, any>} */ (entry);
nodeEntry._appendIterators(iterators);
}
}
}
/**
* @returns {Iterator<T>} the iterator
*/
[Symbol.iterator]() {
const iterators = [];
this._appendIterators(iterators);
iterators.reverse();
let currentIterator = iterators.pop();
return {
next: () => {
const res = currentIterator.next();
if (res.done) {
if (iterators.length === 0) return res;
currentIterator = iterators.pop();
return currentIterator.next();
}
return res;
}
};
}
}
module.exports = LazyBucketSortedSet;