bitmark-grammar/src/typescript-es6/antlr4es6/misc/Arrays.ts

A bitmark parser

/*!
 * Copyright 2016 The ANTLR Project. All rights reserved.
 * Licensed under the BSD-3-Clause license. See LICENSE file in the project root for license information.
 */

export namespace Arrays {
	/**
	 * Searches the specified array of numbers for the specified value using the binary search algorithm. The array must
	 * be sorted prior to making this call. If it is not sorted, the results are unspecified. If the array contains
	 * multiple elements with the specified value, there is no guarantee which one will be found.
	 *
	 * @returns index of the search key, if it is contained in the array; otherwise, (-(insertion point) - 1). The
	 * insertion point is defined as the point at which the key would be inserted into the array: the index of the first
	 * element greater than the key, or array.length if all elements in the array are less than the specified key. Note
	 * that this guarantees that the return value will be >= 0 if and only if the key is found.
	 */
	export function binarySearch(array: ArrayLike<number>, key: number, fromIndex?: number, toIndex?: number): number {
		return binarySearch0(array, fromIndex !== undefined ? fromIndex : 0, toIndex !== undefined ? toIndex : array.length, key);
	}

	function binarySearch0(array: ArrayLike<number>, fromIndex: number, toIndex: number, key: number): number {
		let low: number = fromIndex;
		let high: number = toIndex - 1;

		while (low <= high) {
			let mid: number = (low + high) >>> 1;
			let midVal: number = array[mid];

			if (midVal < key) {
				low = mid + 1;
			} else if (midVal > key) {
				high = mid - 1;
			} else {
				// key found
				return mid;
			}
		}

		// key not found.
		return -(low + 1);
	}

	export function toString<T>(array: Iterable<T>) {
		let result = "[";

		let first = true;
		for (let element of array) {
			if (first) {
				first = false;
			} else {
				result += ", ";
			}

			if (element === null) {
				result += "null";
			} else if (element === undefined) {
				result += "undefined";
			} else {
				result += element;
			}
		}

		result += "]";
		return result;
	}
}