[utils] add class PriorityQueue

utils/index.mjs

@@ -4,3 +4,4 @@ export { readJsonFile, writeJsonFile, parseLogin, waitEvent,
 export { Queue, QueueEmptyError } from './queue.mjs';
 export { AsyncLock } from './async-lock.mjs';
 export { Task, TaskInteruptedError } from './task.mjs';
+export { PriorityQueue } from './priority-queue.mjs';

utils/priority-queue.mjs

@@ -0,0 +1,52 @@
+
+export class PriorityQueue {
+	constructor() {
+		this.val = [null];
+	}
+
+	push(value, priority) {
+		if (priority == null) {
+			priority = value;
+		}
+
+		this.val.push([value, priority]);
+		let id = this.val.length - 1;
+		while (id > 1 && this.val[id][1] > this.val[id >>> 1][1]) {
+			const kid = id >>> 1;
+			[this.val[id], this.val[kid]] = [this.val[kid], this.val[id]];
+			id = kid;
+		}
+		return this;
+	}
+
+	pop() {
+		let lv = this.val.pop();
+		if (this.val.length == 1) { return lv; }
+
+		let res = this.val[1];
+		this.val[1] = lv;
+		let id = 1;
+		while (id * 2 < this.val.length) {
+			if (this.val[id][1] > this.val[id * 2][1] && (id * 2 + 1 >= this.val.length || this.val[id][1] > this.val[id * 2 + 1][1])) {
+				break;
+			}
+
+			let kid = (id * 2 + 1 >= this.val.length || this.val[id * 2][1] > this.val[id * 2 + 1][1]) ? id * 2 : id * 2 + 1;
+			[this.val[id], this.val[kid]] = [this.val[kid], this.val[id]];
+			id = kid;
+		}
+		return res;
+	}
+
+	top() {
+		return this.val[1];
+	}
+
+	size() {
+		return this.val.length - 1;
+	}
+
+	empty() {
+		return this.size() == 0;
+	}
+};