/*!
 * @link https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch
 * @license MIT
 */
(function(win) {
    function convert_compat_string(e) {
        if (e === undefined || e === null || typeof e === 'boolean') {
            e = e ? '1' : '';
        }
        return String(e);
    }
    win.lzw = {
        compress: function (e) {
            e = convert_compat_string(e);
            if (e.length < 2) {
                return e;
            }
            e = e.split('');
            var currChar,
                dict = {},
                out = '',
                phrase = e[0],
                code = 256,
                i = 1;
            for (; i < e.length; i++) {
                currChar = e[i];
                if (dict[phrase + currChar] !== undefined) {
                    phrase += currChar;
                } else {
                    out += (phrase.length > 1 ? String.fromCharCode(dict[phrase]) : phrase[0]);
                    dict[phrase + currChar] = code;
                    code++;
                    phrase = currChar;
                }
            }
            e = null;
            dict = dict[phrase];
            out += (dict !== undefined && phrase.length > 1 ? String.fromCharCode(dict) : phrase);
            return out;
        },
        decompress: function (e) {
            e = convert_compat_string(e);
            if (e.length < 2) {
                return e;
            }
            var currCode,
                dict = {},
                currChar = e[0],
                oldPhrase = currChar,
                out = currChar,
                code = 256,
                phrase,
                i = 1;
            for (; i < e.length; i++) {
                currCode = e[i].charCodeAt(0);
                if (currCode < 256) {
                    phrase = e[i];
                } else {
                    phrase = dict[currCode] ? dict[currCode] : (oldPhrase + currChar);
                }
                out += phrase;
                currChar = phrase.charAt(0);
                dict[code] = oldPhrase + currChar;
                code++;
                oldPhrase = phrase;
            }

            e = dict = null;
            return out;
        }
    };
})(self);