1 files changed, 69 insertions, 0 deletions
diff --git a/node_modules/webpack/lib/util/ParallelismFactorCalculator.js b/node_modules/webpack/lib/util/ParallelismFactorCalculator.js
new file mode 100644
index 00000000..415ff368
--- /dev/null
+++ b/node_modules/webpack/lib/util/ParallelismFactorCalculator.js
@@ -0,0 +1,69 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const binarySearchBounds = require("../util/binarySearchBounds");
+
+/** @typedef {function(number): void} Callback */
+
+class ParallelismFactorCalculator {
+	constructor() {
+		/** @type {number[]} */
+		this._rangePoints = [];
+		/** @type {Callback[]} */
+		this._rangeCallbacks = [];
+	}
+
+	/**
+	 * @param {number} start range start
+	 * @param {number} end range end
+	 * @param {Callback} callback callback
+	 * @returns {void}
+	 */
+	range(start, end, callback) {
+		if (start === end) return callback(1);
+		this._rangePoints.push(start);
+		this._rangePoints.push(end);
+		this._rangeCallbacks.push(callback);
+	}
+
+	calculate() {
+		const segments = Array.from(new Set(this._rangePoints)).sort((a, b) =>
+			a < b ? -1 : 1
+		);
+		const parallelism = segments.map(() => 0);
+		const rangeStartIndices = [];
+		for (let i = 0; i < this._rangePoints.length; i += 2) {
+			const start = this._rangePoints[i];
+			const end = this._rangePoints[i + 1];
+			let idx = binarySearchBounds.eq(segments, start);
+			rangeStartIndices.push(idx);
+			do {
+				parallelism[idx]++;
+				idx++;
+			} while (segments[idx] < end);
+		}
+		for (let i = 0; i < this._rangeCallbacks.length; i++) {
+			const start = this._rangePoints[i * 2];
+			const end = this._rangePoints[i * 2 + 1];
+			let idx = rangeStartIndices[i];
+			let sum = 0;
+			let totalDuration = 0;
+			let current = start;
+			do {
+				const p = parallelism[idx];
+				idx++;
+				const duration = segments[idx] - current;
+				totalDuration += duration;
+				current = segments[idx];
+				sum += p * duration;
+			} while (current < end);
+			this._rangeCallbacks[i](sum / totalDuration);
+		}
+	}
+}
+
+module.exports = ParallelismFactorCalculator;