utf8 safe base64 module for YUI3

/**
*
*  Base64 encode / decode
*  http://www.webtoolkit.info/
*
*  Wrapped into YUI3 module by Zaar Hai haizaar at haizaar dot com
*
**/

YUI.add("webtoolkit-base64", function(Y){


        // private property
        var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

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

                input = _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 +
                        _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
                        _keyStr.charAt(enc3) + _keyStr.charAt(enc4);

                }

                return output;
        }

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

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

                while (i < input.length) {

                        enc1 = _keyStr.indexOf(input.charAt(i++));
                        enc2 = _keyStr.indexOf(input.charAt(i++));
                        enc3 = _keyStr.indexOf(input.charAt(i++));
                        enc4 = _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);
                        }

                }

                output = _utf8_decode(output);

                return output;

        }

        // private method for UTF-8 encoding
        function _utf8_encode(string) {
                string = string.replace(/\r\n/g,"\n");
                var utftext = "";

                for (var n = 0; n < string.length; n++) {

                        var 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
        function _utf8_decode(utftext) {
                var string = "";
                var i = 0;
                var c = c1 = c2 = 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;
        }

        Y.namespace("Base64");
        Y.Base64.encode = encode;
        Y.Base64.decode = decode;

}, "1.0", {requires: ['base']});