(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.base64 = factory());
})(this, (function () { 'use strict';

	/* ------------------------------------------------------------------------------------

	  base64 - MIT License - Hexagon <hexagon@56k.guru>

	  ------------------------------------------------------------------------------------

	  License:

		Copyright (c) 2021 Hexagon <hexagon@56k.guru>

		Permission is hereby granted, free of charge, to any person obtaining a copy
		of this software and associated documentation files (the "Software"), to deal
		in the Software without restriction, including without limitation the rights
		to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
		copies of the Software, and to permit persons to whom the Software is
		furnished to do so, subject to the following conditions:
		The above copyright notice and this permission notice shall be included in
		all copies or substantial portions of the Software.
		THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
		IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
		FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
		AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
		LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
		OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
		THE SOFTWARE.

	  ------------------------------------------------------------------------------------  */

	const 
		// Regular base64 characters
		chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",

		// Base64url characters
		charsUrl = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_",

		genLookup = (target) => {
			const lookupTemp = typeof Uint8Array === "undefined" ? [] : new Uint8Array(256);
			const len = chars.length;
			for (let i = 0; i < len; i++) {
				lookupTemp[target.charCodeAt(i)] = i;
			}
			return lookupTemp;
		},
	  
		// Use a lookup table to find the index.
		lookup = genLookup(chars),
		lookupUrl = genLookup(charsUrl); 

	/**
	 * Pre-calculated regexes for validating base64 and base64url
	 */
	const base64UrlPattern = /^[-A-Za-z0-9\-_]*$/;
	const base64Pattern = /^[-A-Za-z0-9+/]*={0,3}$/;

	/**
	 * @namespace base64
	 */
	const base64 = {};

	/**
	 * Convenience function for converting a base64 encoded string to an ArrayBuffer instance
	 * @public
	 * 
	 * @param {string} data - Base64 representation of data
	 * @param {boolean} [urlMode] - If set to true, URL mode string will be expected
	 * @returns {ArrayBuffer} - Decoded data
	 */
	base64.toArrayBuffer = (data, urlMode) => {
		const 
			len = data.length;
		let bufferLength = data.length * 0.75,
			i,
			p = 0,
			encoded1,
			encoded2,
			encoded3,
			encoded4;

		if (data[data.length - 1] === "=") {
			bufferLength--;
			if (data[data.length - 2] === "=") {
				bufferLength--;
			}
		}

		const 
			arraybuffer = new ArrayBuffer(bufferLength),
			bytes = new Uint8Array(arraybuffer),
			target = urlMode ? lookupUrl : lookup;

		for (i = 0; i < len; i += 4) {
			encoded1 = target[data.charCodeAt(i)];
			encoded2 = target[data.charCodeAt(i + 1)];
			encoded3 = target[data.charCodeAt(i + 2)];
			encoded4 = target[data.charCodeAt(i + 3)];

			bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
			bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
			bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
		}

		return arraybuffer;

	};

	/**
	 * Convenience function for creating a base64 encoded string from an ArrayBuffer instance
	 * @public
	 * 
	 * @param {ArrayBuffer} arrBuf - ArrayBuffer to be encoded
	 * @param {boolean} [urlMode] - If set to true, URL mode string will be returned
	 * @returns {string} - Base64 representation of data
	 */
	base64.fromArrayBuffer = (arrBuf, urlMode) => {
		const bytes = new Uint8Array(arrBuf);
		let
			i,
			result = "";

		const
			len = bytes.length,
			target = urlMode ? charsUrl : chars;

		for (i = 0; i < len; i += 3) {
			result += target[bytes[i] >> 2];
			result += target[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
			result += target[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
			result += target[bytes[i + 2] & 63];
		}

		const remainder = len % 3;
		if (remainder === 2) {
			result = result.substring(0, result.length - 1) + (urlMode ? "" : "=");
		} else if (remainder === 1) {
			result = result.substring(0, result.length - 2) + (urlMode ? "" : "==");
		}

		return result;

	};

	/**
	 * Convenience function for converting base64 to string
	 * @public
	 * 
	 * @param {string} str - Base64 encoded string to be decoded
	 * @param {boolean} [urlMode] - If set to true, URL mode string will be expected
	 * @returns {string} - Decoded string
	 */
	base64.toString = (str, urlMode) => {
		return new TextDecoder().decode(base64.toArrayBuffer(str, urlMode));
	};

	/**
	 * Convenience function for converting a javascript string to base64
	 * @public
	 * 
	 * @param {string} str - String to be converted to base64
	 * @param {boolean} [urlMode] - If set to true, URL mode string will be returned
	 * @returns {string} - Base64 encoded string
	 */
	base64.fromString = (str, urlMode) => {
		return base64.fromArrayBuffer(new TextEncoder().encode(str), urlMode);
	};

	/**
	 * Function to validate base64
	 * @public
	 * @param {string} encoded - Base64 or Base64url encoded data
	 * @param {boolean} [urlMode] - If set to true, base64url will be expected
	 * @returns {boolean} - Valid base64/base64url?
	 */
	base64.validate = (encoded, urlMode) => {

		// Bail out if not string
		if (!(typeof encoded === "string" || encoded instanceof String)) {
			return false;
		}

		// Go on validate
		try {
			return urlMode ? base64UrlPattern.test(encoded) : base64Pattern.test(encoded);
		} catch (_e) {
			return false;
		}
	};

	base64.base64 = base64;

	return base64;

}));
