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"use strict";

/*jslint bitwise: false */

function encode64(s) {
	// the result/encrypted string, the padding string, and the pad count
	var r = "", p = "", c = s.length % 3, n,
	chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'.split("");

	// add a right zero pad to make this string a multiple of 3 characters
	if (c > 0) {
		for (; c < 3; c++) {
			p += '=';
			s += String.fromCharCode(0);
		}
	}

	// increment over the length of the string, three characters at a time
	for (c = 0; c < s.length; c += 3) {

		// we add newlines after every 76 output characters, according to
		// the MIME specs
		if (c > 0 && (c / 3 * 4) % 76 === 0) {
			r += "\r\n";
		}

		// these three 8-bit (ASCII) characters become one 24-bit number
		n =
			(s.charCodeAt(c) << 16) +
			(s.charCodeAt(c + 1) << 8) +
			s.charCodeAt(c + 2);

		// this 24-bit number gets separated into four 6-bit numbers
		n = [(n >>> 18) & 63, (n >>> 12) & 63, (n >>> 6) & 63, n & 63];

		// those four 6-bit numbers are used as indices into the
		// base64 character list
		r +=
			chars[n[0]] +
			chars[n[1]] +
			chars[n[2]] +
			chars[n[3]];
	}

	// add the actual padding string, after removing the zero pad
	return r.substring(0, r.length - p.length) + p;
}