snappymail/dev/Common/Base64.js

// Base64 encode / decode
// http://www.webtoolkit.info/

(function () {

	'use strict';

	/*jslint bitwise: true*/
	var Base64 = {

		// private property
		_keyStr : 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',

		// public method for urlsafe encoding
		urlsafe_encode : function (input) {
			return Base64.encode(input).replace(/[+]/g, '-').replace(/[\/]/g, '_').replace(/[=]/g, '.');
		},

		// public method for encoding
		encode : function (input) {
			var
				output = '',
				chr1, chr2, chr3, enc1, enc2, enc3, enc4,
				i = 0
			;

			input = Base64._utf8_encode(input);

			while (i < input.length)
			{
				chr1 = input.charCodeAt(i++);
				chr2 = input.charCodeAt(i++);
				chr3 = input.charCodeAt(i++);

				enc1 = chr1 >> 2;
				enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
				enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
				enc4 = chr3 & 63;

				if (isNaN(chr2))
				{
					enc3 = enc4 = 64;
				}
				else if (isNaN(chr3))
				{
					enc4 = 64;
				}

				output = output +
					this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
					this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
			}

			return output;
		},

		// public method for decoding
		decode : function (input) {
			var
				output = '',
				chr1, chr2, chr3, enc1, enc2, enc3, enc4,
				i = 0
			;

			input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '');

			while (i < input.length)
			{
				enc1 = this._keyStr.indexOf(input.charAt(i++));
				enc2 = this._keyStr.indexOf(input.charAt(i++));
				enc3 = this._keyStr.indexOf(input.charAt(i++));
				enc4 = this._keyStr.indexOf(input.charAt(i++));

				chr1 = (enc1 << 2) | (enc2 >> 4);
				chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
				chr3 = ((enc3 & 3) << 6) | enc4;

				output = output + String.fromCharCode(chr1);

				if (enc3 !== 64)
				{
					output = output + String.fromCharCode(chr2);
				}

				if (enc4 !== 64)
				{
					output = output + String.fromCharCode(chr3);
				}
			}

			return Base64._utf8_decode(output);
		},

		// private method for UTF-8 encoding
		_utf8_encode : function (string) {

			string = string.replace(/\r\n/g, "\n");

			var
				utftext = '',
				n = 0,
				l = string.length,
				c = 0
			;

			for (; n < l; n++) {

				c = string.charCodeAt(n);

				if (c < 128)
				{
					utftext += String.fromCharCode(c);
				}
				else if ((c > 127) && (c < 2048))
				{
					utftext += String.fromCharCode((c >> 6) | 192);
					utftext += String.fromCharCode((c & 63) | 128);
				}
				else
				{
					utftext += String.fromCharCode((c >> 12) | 224);
					utftext += String.fromCharCode(((c >> 6) & 63) | 128);
					utftext += String.fromCharCode((c & 63) | 128);
				}
			}

			return utftext;
		},

		// private method for UTF-8 decoding
		_utf8_decode : function (utftext) {
			var
				string = '',
				i = 0,
				c = 0,
				c2 = 0,
				c3 = 0
			;

			while ( i < utftext.length )
			{
				c = utftext.charCodeAt(i);

				if (c < 128)
				{
					string += String.fromCharCode(c);
					i++;
				}
				else if((c > 191) && (c < 224))
				{
					c2 = utftext.charCodeAt(i+1);
					string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
					i += 2;
				}
				else
				{
					c2 = utftext.charCodeAt(i+1);
					c3 = utftext.charCodeAt(i+2);
					string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
					i += 3;
				}
			}

			return string;
		}
	};

	module.exports = Base64;
	/*jslint bitwise: false*/

}());