base64.ts

/*
 * Copyright (c) 2013 Kevin van Zonneveld (http://kvz.io)
 * and Contributors (http://phpjs.org/authors)
 * 
 * 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.
 */

// Deprecated and removed in TypeScript
declare function unescape(s: string): string;

/**
 * Encode string as base64.
 * Any type can be passed, but will be stringified
 *
 * @param data string to encode
 * @returns base64-encoded string
 */
export function base64encode(data: string): string {
	// discuss at: http://phpjs.org/functions/base64_encode/
	// original by: Tyler Akins (http://rumkin.com)
	// improved by: Bayron Guevara
	// improved by: Thunder.m
	// improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
	// improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
	// improved by: Rafał Kukawski (http://kukawski.pl)
	// bugfixed by: Pellentesque Malesuada
	// example 1: base64_encode('Kevin van Zonneveld');
	// returns 1: 'S2V2aW4gdmFuIFpvbm5ldmVsZA=='
	// example 2: base64_encode('a');
	// returns 2: 'YQ=='
	// example 3: base64_encode('✓ à la mode');
	// returns 3: '4pyTIMOgIGxhIG1vZGU='

	var b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
	var o1, o2, o3, h1, h2, h3, h4, bits, i = 0,
		ac = 0,
		enc: string,
		tmp_arr: Array<string> = [];

	if (!data) {
		return data;
	}

	data = unescape(encodeURIComponent(data));

	do {
		// pack three octets into four hexets
		o1 = data.charCodeAt(i++);
		o2 = data.charCodeAt(i++);
		o3 = data.charCodeAt(i++);

		bits = o1 << 16 | o2 << 8 | o3;

		h1 = bits >> 18 & 0x3f;
		h2 = bits >> 12 & 0x3f;
		h3 = bits >> 6 & 0x3f;
		h4 = bits & 0x3f;

		// use hexets to index into b64, and append result to encoded string
		tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
	} while (i < data.length);

	enc = tmp_arr.join('');

	var r = data.length % 3;

	return (r ? enc.slice(0, r - 3) : enc) + '==='.slice(r || 3);
}