;
(function() {

    var object = typeof exports != 'undefined' ? exports : this; // #8: web workers
    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

    function InvalidCharacterError(message) {
        this.message = message;
    }
    InvalidCharacterError.prototype = new Error;
    InvalidCharacterError.prototype.name = 'InvalidCharacterError';

    // encoder
    // [https://gist.github.com/999166] by [https://github.com/nignag]
    object.btoa || (
        object.btoa = function(input) {
            var str = String(input);
            for (
                // initialize result and counter
                var block, charCode, idx = 0, map = chars, output = '';
                // if the next str index does not exist:
                //   change the mapping table to "="
                //   check if d has no fractional digits
                str.charAt(idx | 0) || (map = '=', idx % 1);
                // "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
                output += map.charAt(63 & block >> 8 - idx % 1 * 8)
            ) {
                charCode = str.charCodeAt(idx += 3 / 4);
                if (charCode > 0xFF) {
                    throw new InvalidCharacterError("'btoa' failed: The string to be encoded contains characters outside of the Latin1 range.");
                }
                block = block << 8 | charCode;
            }
            return output;
        });

    // decoder
    // [https://gist.github.com/1020396] by [https://github.com/atk]
    object.atob || (
        object.atob = function(input) {
            var str = String(input).replace(/=+$/, '');
            if (str.length % 4 == 1) {
                throw new InvalidCharacterError("'atob' failed: The string to be decoded is not correctly encoded.");
            }
            for (
                // initialize result and counters
                var bc = 0, bs, buffer, idx = 0, output = '';
                // get next character
                buffer = str.charAt(idx++);
                // character found in table? initialize bit storage and add its ascii value;
                ~ buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
                    // and if not first of each 4 characters,
                    // convert the first 8 bits to one ascii character
                    bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
            ) {
                // try to find character in table (0-63, not found => -1)
                buffer = chars.indexOf(buffer);
            }
            return output;
        });

}());