Merge from master

src/vs/base/common/range.ts

@@ -0,0 +1,60 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+export interface IRange {
+	start: number;
+	end: number;
+}
+
+export interface IRangedGroup {
+	range: IRange;
+	size: number;
+}
+
+export namespace Range {
+
+	/**
+	 * Returns the intersection between two ranges as a range itself.
+	 * Returns `{ start: 0, end: 0 }` if the intersection is empty.
+	 */
+	export function intersect(one: IRange, other: IRange): IRange {
+		if (one.start >= other.end || other.start >= one.end) {
+			return { start: 0, end: 0 };
+		}
+
+		const start = Math.max(one.start, other.start);
+		const end = Math.min(one.end, other.end);
+
+		if (end - start <= 0) {
+			return { start: 0, end: 0 };
+		}
+
+		return { start, end };
+	}
+
+	export function isEmpty(range: IRange): boolean {
+		return range.end - range.start <= 0;
+	}
+
+	export function intersects(one: IRange, other: IRange): boolean {
+		return !isEmpty(intersect(one, other));
+	}
+
+	export function relativeComplement(one: IRange, other: IRange): IRange[] {
+		const result: IRange[] = [];
+		const first = { start: one.start, end: Math.min(other.start, one.end) };
+		const second = { start: Math.max(other.end, one.start), end: one.end };
+
+		if (!isEmpty(first)) {
+			result.push(first);
+		}
+
+		if (!isEmpty(second)) {
+			result.push(second);
+		}
+
+		return result;
+	}
+}