UTF-8 - Base64

utf8-base64.js

/*
Copyright Vassilis Petroulias [DRDigit]
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
       http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
var B64 = {
    alphabet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
    lookup: null,
    ie: /MSIE /.test(navigator.userAgent),
    ieo: /MSIE [67]/.test(navigator.userAgent),
    encode: function (s) {
        /* jshint bitwise:false */
        var buffer = B64.toUtf8(s),
            position = -1,
            result,
            len = buffer.length,
            nan0, nan1, nan2, enc = [, , , ];
        
        if (B64.ie) {
            result = [];
            while (++position < len) {
                nan0 = buffer[position];
                nan1 = buffer[++position];
                enc[0] = nan0 >> 2;
                enc[1] = ((nan0 & 3) << 4) | (nan1 >> 4);
                if (isNaN(nan1))
                    enc[2] = enc[3] = 64;
                else {
                    nan2 = buffer[++position];
                    enc[2] = ((nan1 & 15) << 2) | (nan2 >> 6);
                    enc[3] = (isNaN(nan2)) ? 64 : nan2 & 63;
                }
                result.push(B64.alphabet.charAt(enc[0]), B64.alphabet.charAt(enc[1]), B64.alphabet.charAt(enc[2]), B64.alphabet.charAt(enc[3]));
            }
            return result.join('');
        } else {
            result = '';
            while (++position < len) {
                nan0 = buffer[position];
                nan1 = buffer[++position];
                enc[0] = nan0 >> 2;
                enc[1] = ((nan0 & 3) << 4) | (nan1 >> 4);
                if (isNaN(nan1))
                    enc[2] = enc[3] = 64;
                else {
                    nan2 = buffer[++position];
                    enc[2] = ((nan1 & 15) << 2) | (nan2 >> 6);
                    enc[3] = (isNaN(nan2)) ? 64 : nan2 & 63;
                }
                result += B64.alphabet[enc[0]] + B64.alphabet[enc[1]] + B64.alphabet[enc[2]] + B64.alphabet[enc[3]];
            }
            return result;
        }
    },
    decode: function (s) {
        /* jshint bitwise:false */
        s = s.replace(/\s/g, '');
        if (s.length % 4)
            throw new Error('InvalidLengthError: decode failed: The string to be decoded is not the correct length for a base64 encoded string.');
        if(/[^A-Za-z0-9+\/=\s]/g.test(s))
            throw new Error('InvalidCharacterError: decode failed: The string contains characters invalid in a base64 encoded string.');

        var buffer = B64.fromUtf8(s),
            position = 0,
            result,
            len = buffer.length;

        if (B64.ieo) {
            result = [];
            while (position < len) {
                if (buffer[position] < 128)
                    result.push(String.fromCharCode(buffer[position++]));
                else if (buffer[position] > 191 && buffer[position] < 224)
                    result.push(String.fromCharCode(((buffer[position++] & 31) << 6) | (buffer[position++] & 63)));
                else
                    result.push(String.fromCharCode(((buffer[position++] & 15) << 12) | ((buffer[position++] & 63) << 6) | (buffer[position++] & 63)));
            }
            return result.join('');
        } else {
            result = '';
            while (position < len) {
                if (buffer[position] < 128)
                    result += String.fromCharCode(buffer[position++]);
                else if (buffer[position] > 191 && buffer[position] < 224)
                    result += String.fromCharCode(((buffer[position++] & 31) << 6) | (buffer[position++] & 63));
                else
                    result += String.fromCharCode(((buffer[position++] & 15) << 12) | ((buffer[position++] & 63) << 6) | (buffer[position++] & 63));
            }
            return result;
        }
    },
    toUtf8: function (s) {
        /* jshint bitwise:false */
        var position = -1,
            len = s.length,
            chr, buffer = [];
        if (/^[\x00-\x7f]*$/.test(s)) while (++position < len)
            buffer.push(s.charCodeAt(position));
        else while (++position < len) {
            chr = s.charCodeAt(position);
            if (chr < 128)
                buffer.push(chr);
            else if (chr < 2048)
                buffer.push((chr >> 6) | 192, (chr & 63) | 128);
            else
                buffer.push((chr >> 12) | 224, ((chr >> 6) & 63) | 128, (chr & 63) | 128);
        }
        return buffer;
    },
    fromUtf8: function (s) {
        /* jshint bitwise:false */
        var position = -1,
            len, buffer = [],
            enc = [, , , ];
        if (!B64.lookup) {
            len = B64.alphabet.length;
            B64.lookup = {};
            while (++position < len)
                B64.lookup[B64.alphabet.charAt(position)] = position;
            position = -1;
        }
        len = s.length;
        while (++position < len) {
            enc[0] = B64.lookup[s.charAt(position)];
            enc[1] = B64.lookup[s.charAt(++position)];
            buffer.push((enc[0] << 2) | (enc[1] >> 4));
            enc[2] = B64.lookup[s.charAt(++position)];
            if (enc[2] === 64)
                break;
            buffer.push(((enc[1] & 15) << 4) | (enc[2] >> 2));
            enc[3] = B64.lookup[s.charAt(++position)];
            if (enc[3] === 64)
                break;
            buffer.push(((enc[2] & 3) << 6) | enc[3]);
        }
        return buffer;
    }
};

var B64url = {
    decode: function(input) {
        // Replace non-url compatible chars with base64 standard chars
        input = input
            .replace(/-/g, '+')
            .replace(/_/g, '/');

        // Pad out with standard base64 required padding characters
        var pad = input.length % 4;
        if(pad) {
          if(pad === 1) {
            throw new Error('InvalidLengthError: Input base64url string is the wrong length to determine padding');
          }
          input += new Array(5-pad).join('=');
        }

        return B64.decode(input);
    },

    encode: function(input) {
        var output = B64.encode(input);
        return output
            .replace(/\+/g, '-')
            .replace(/\//g, '_')
            .split('=', 1)[0];
    }
};