/**
 * Roundcube common js library
 *
 * This file is part of the Roundcube Webmail client
 *
 * @licstart  The following is the entire license notice for the
 * JavaScript code in this file.
 *
 * Copyright (c) The Roundcube Dev Team
 *
 * The JavaScript code in this page is free software: you can
 * redistribute it and/or modify it under the terms of the GNU
 * General Public License (GNU GPL) as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.  The code is distributed WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute non-source (e.g., minimized or compacted) forms of
 * that code without the copy of the GNU GPL normally required by
 * section 4, provided you include this license notice and a URL
 * through which recipients can access the Corresponding Source.
 *
 * @licend  The above is the entire license notice
 * for the JavaScript code in this file.
 */

// Constants
var CONTROL_KEY = 1;
var SHIFT_KEY = 2;
var CONTROL_SHIFT_KEY = 3;

/**
 * Default browser check class
 * @constructor
 */
function roundcube_browser() {
    var n = navigator;

    this.agent = n.userAgent;
    this.agent_lc = n.userAgent.toLowerCase();
    this.name = n.appName;
    this.vendor = n.vendor ? n.vendor : '';
    this.vendver = n.vendorSub ? parseFloat(n.vendorSub) : 0;
    this.product = n.product ? n.product : '';
    this.platform = String(n.platform).toLowerCase();
    this.lang = n.language ? n.language.substring(0, 2)
        : n.browserLanguage ? n.browserLanguage.substring(0, 2)
            : n.systemLanguage ? n.systemLanguage.substring(0, 2) : 'en';

    this.win = this.platform.indexOf('win') >= 0;
    this.mac = this.platform.indexOf('mac') >= 0;
    this.linux = this.platform.indexOf('linux') >= 0;
    this.unix = this.platform.indexOf('unix') >= 0;

    this.dom = document.getElementById ? true : false;
    this.dom2 = document.addEventListener && document.removeEventListener;

    this.edge = this.agent_lc.indexOf(' edge/') > 0 || this.agent_lc.indexOf(' edg/') > 0; // "edg" in Chromium based Edge
    this.webkit = !this.edge && this.agent_lc.indexOf('applewebkit') > 0;
    this.ie = (document.all && !window.opera) || (this.win && this.agent_lc.indexOf('trident/') > 0);

    if (window.opera) {
        this.opera = true; // Opera < 15
        this.vendver = opera.version();
    } else if (!this.ie && !this.edge) {
        this.chrome = this.agent_lc.indexOf('chrome') > 0;
        this.opera = this.webkit && this.agent.indexOf(' OPR/') > 0; // Opera >= 15
        this.safari = !this.chrome && !this.opera && (this.webkit || this.agent_lc.indexOf('safari') > 0);
        this.konq = this.agent_lc.indexOf('konqueror') > 0;
        this.mz = this.dom && !this.chrome && !this.safari && !this.konq && !this.opera && this.agent.indexOf('Mozilla') >= 0;
        this.iphone = this.safari && (this.agent_lc.indexOf('iphone') > 0 || this.agent_lc.indexOf('ipod') > 0 || this.platform == 'ipod' || this.platform == 'iphone');
        this.ipad = this.safari && (this.agent_lc.indexOf('ipad') > 0 || this.platform == 'ipad');
    }

    if (!this.vendver) {
        if (this.ie) {
            pattern = /(msie|rv)(\s|:)([0-9\.]+)/;
        } else if (this.edge) {
            pattern = /(edge?)(\/)([0-9\.]+)/;
        } else if (this.opera) {
            pattern = /(opera|opr)(\/)([0-9\.]+)/;
        } else if (this.konq) {
            pattern = /(konqueror)(\/)([0-9\.]+)/;
        } else if (this.safari) {
            pattern = /(version)(\/)([0-9\.]+)/;
        } else if (this.chrome) {
            pattern = /(chrome)(\/)([0-9\.]+)/;
        } else if (this.mz) {
            pattern = /(firefox)(\/)([0-9\.]+)/;
        } else {
            pattern = /(khtml|safari|applewebkit|rv)(\s|\/|:)([0-9\.]+)/;
        }

        // common version strings
        this.vendver = pattern.test(this.agent_lc) ? parseFloat(RegExp.$3) : 0;
    }

    // get real language out of safari's user agent
    if (this.safari && (/;\s+([a-z]{2})-[a-z]{2}\)/.test(this.agent_lc))) {
        this.lang = RegExp.$1;
    }

    this.mobile = /iphone|ipod|blackberry|iemobile|opera mini|opera mobi|mobile/i.test(this.agent_lc);
    this.tablet = !this.mobile && /ipad|android|xoom|sch-i800|playbook|tablet|kindle/i.test(this.agent_lc);
    this.touch = this.mobile || this.tablet;
    this.pointer = typeof window.PointerEvent === 'function';
    this.cookies = n.cookieEnabled;

    // set class names to html tag according to the current user agent detection
    // this allows browser-specific css selectors like "html.chrome .someclass"
    this.set_html_class = function () {
        var classname = ' js';

        if (this.ie) {
            classname += ' ms ie ie' + parseInt(this.vendver, 10);
        } else if (this.edge && this.vendver > 74) {
            classname += ' chrome';
        } else if (this.edge) {
            classname += ' ms edge';
        } else if (this.opera) {
            classname += ' opera';
        } else if (this.konq) {
            classname += ' konqueror';
        } else if (this.safari) {
            classname += ' chrome';
        } else if (this.chrome) {
            classname += ' chrome';
        } else if (this.mz) {
            classname += ' mozilla';
        }

        if (this.iphone) {
            classname += ' iphone';
        } else if (this.ipad) {
            classname += ' ipad';
        } else if (this.webkit) {
            classname += ' webkit';
        }

        if (this.mobile) {
            classname += ' mobile';
        }
        if (this.tablet) {
            classname += ' tablet';
        }

        if (document.documentElement) {
            document.documentElement.className += classname;
        }
    };
}


// static functions for DOM event handling
var rcube_event = {

    /**
     * returns the event target element
     */
    get_target: function (e) {
        e = e || window.event;
        return e && e.target ? e.target : e.srcElement || document;
    },

    /**
     * returns the event key code
     */
    get_keycode: function (e) {
        e = e || window.event;
        return e && e.keyCode ? e.keyCode : (e && e.which ? e.which : 0);
    },

    /**
     * returns the event key code
     */
    get_button: function (e) {
        e = e || window.event;
        return e && e.button !== undefined ? e.button : (e && e.which ? e.which : 0);
    },

    /**
     * returns modifier key (constants defined at top of file)
     */
    get_modifier: function (e) {
        var opcode = 0;
        e = e || window.event;

        if (bw.mac && e) {
            opcode += (e.metaKey && CONTROL_KEY) + (e.shiftKey && SHIFT_KEY);
        } else if (e) {
            opcode += (e.ctrlKey && CONTROL_KEY) + (e.shiftKey && SHIFT_KEY);
        }

        return opcode;
    },

    /**
     * Return absolute mouse position of an event
     */
    get_mouse_pos: function (e) {
        if (!e) {
            e = window.event;
        }
        var mX = (e.pageX) ? e.pageX : e.clientX,
            mY = (e.pageY) ? e.pageY : e.clientY;

        if (document.body && document.all) {
            mX += document.body.scrollLeft;
            mY += document.body.scrollTop;
        }

        if (e._offset) {
            mX += e._offset.left;
            mY += e._offset.top;
        }

        return { x: mX, y: mY };
    },

    /**
     * Add an object method as event listener to a certain element
     */
    add_listener: function (p) {
        if (!p.object || !p.method) { // not enough arguments
            return;
        }
        if (!p.element) {
            p.element = document;
        }

        if (!p.object._rc_events) {
            p.object._rc_events = {};
        }

        var key = p.event + '*' + p.method;
        if (!p.object._rc_events[key]) {
            p.object._rc_events[key] = function (e) {
                return p.object[p.method](e);
            };
        }

        if (p.element.addEventListener) {
            p.element.addEventListener(p.event, p.object._rc_events[key], false);
        } else if (p.element.attachEvent) {
            // IE allows multiple events with the same function to be applied to the same object
            // forcibly detach the event, then attach
            p.element.detachEvent('on' + p.event, p.object._rc_events[key]);
            p.element.attachEvent('on' + p.event, p.object._rc_events[key]);
        } else {
            p.element['on' + p.event] = p.object._rc_events[key];
        }
    },

    /**
     * Remove event listener
     */
    remove_listener: function (p) {
        if (!p.element) {
            p.element = document;
        }

        var key = p.event + '*' + p.method;
        if (p.object && p.object._rc_events && p.object._rc_events[key]) {
            if (p.element.removeEventListener) {
                p.element.removeEventListener(p.event, p.object._rc_events[key], false);
            } else if (p.element.detachEvent) {
                p.element.detachEvent('on' + p.event, p.object._rc_events[key]);
            } else {
                p.element['on' + p.event] = null;
            }
        }
    },

    /**
     * Prevent event propagation and bubbling
     */
    cancel: function (evt) {
        var e = evt ? evt : window.event;

        if (e.preventDefault) {
            e.preventDefault();
        } else {
            e.returnValue = false;
        }

        if (e.stopPropagation) {
            e.stopPropagation();
        }

        e.cancelBubble = true;

        return false;
    },

    /**
     * Determine whether the given event was triggered from keyboard
     */
    is_keyboard: function (e) {
        if (!e) {
            return false;
        }

        // DOM3-compatible
        // An event invoked by pressing Enter on a link will produce a 'click' event,
        // so we have to extend the check, e.g. with use of e.clientX.
        if (e.type) {
            return !!e.type.match(/^key/) || (e.type == 'click' && !e.clientX);
        }

        // Old browsers
        return !e.pageX && (e.pageY || 0) <= 0 && !e.clientX && (e.clientY || 0) <= 0;
    },

    /**
     * Accept event if triggered from keyboard action (e.g. <Enter>)
     */
    keyboard_only: function (e) {
        return rcube_event.is_keyboard(e) ? true : rcube_event.cancel(e);
    },

    touchevent: function (e) {
        return {
            pageX: e.pageX, pageY: e.pageY, offsetX: e.pageX - e.target.offsetLeft, offsetY: e.pageY - e.target.offsetTop, target: e.target, istouch: true,
        };
    },

};


/**
 * rcmail objects event interface
 */
function rcube_event_engine() {
    this._events = {};
}

rcube_event_engine.prototype = {

    /**
     * Setter for object event handlers
     *
     * @param {String}   Event name
     * @param {Function} Handler function
     */
    addEventListener: function (evt, func, obj) {
        if (!this._events) {
            this._events = {};
        }
        if (!this._events[evt]) {
            this._events[evt] = [];
        }

        this._events[evt].push({ func: func, obj: obj ? obj : window });

        return this; // chainable
    },

    /**
     * Removes a specific event listener
     *
     * @param {String} Event name
     * @param {Int}    Listener ID to remove
     */
    removeEventListener: function (evt, func, obj) {
        if (obj === undefined) {
            obj = window;
        }

        for (var h, i = 0; this._events && this._events[evt] && i < this._events[evt].length; i++) {
            if ((h = this._events[evt][i]) && h.func == func && h.obj == obj) {
                this._events[evt][i] = null;
            }
        }
    },

    /**
     * This will execute all registered event handlers
     *
     * @param {String} Event to trigger
     * @param {Object} Event object/arguments
     */
    triggerEvent: function (evt, e) {
        var ret, h,
            reset_fn = function (o) {
                try {
                    if (o && o.event) {
                        delete o.event;
                    }
                } catch (err) {}
            };

        if (e === undefined) {
            e = this;
        } else if (typeof e === 'object') {
            e.event = evt;
        }

        if (!this._event_exec) {
            this._event_exec = {};
        }

        if (this._events && this._events[evt] && !this._event_exec[evt]) {
            this._event_exec[evt] = true;
            for (var i = 0; i < this._events[evt].length; i++) {
                if ((h = this._events[evt][i])) {
                    if (typeof h.func === 'function') {
                        ret = h.func.call ? h.func.call(h.obj, e) : h.func(e);
                    } else if (typeof h.obj[h.func] === 'function') {
                        ret = h.obj[h.func](e);
                    }

                    // cancel event execution
                    if (ret !== undefined && !ret) {
                        break;
                    }
                }
            }
            reset_fn(ret);
        }

        delete this._event_exec[evt];
        reset_fn(e);

        return ret;
    },

}; // end rcube_event_engine.prototype


// check if input is a valid email address
// By Cal Henderson <cal@iamcal.com>
// https://code.iamcal.com/php/rfc822/
function rcube_check_email(input, inline, count, strict) {
    if (!input) {
        return count ? 0 : false;
    }

    if (count) {
        inline = true;
    }

    var qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]',
        dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]',
        atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+',
        quoted_pair = '\\x5c[\\x00-\\x7f]',
        quoted_string = '\\x22(' + qtext + '|' + quoted_pair + ')*\\x22',
        ipv4 = '\\[(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(\\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])){3}\\]',
        ipv6 = '\\[IPv6:[0-9a-f:.]+\\]',
        ip_addr = '(' + ipv4 + ')|(' + ipv6 + ')',
        // Use simplified domain matching, because we need to allow Unicode characters here
        // So, e-mail address should be validated also on server side after idn_to_ascii()
        // Allow punycode/unicode top-level domains, allow extended domains (#5588)
        // Allow a domain ending with .s (#8854)
        domain = '((' + ip_addr + ')|(([^@.]+\\.)+([^\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\x7f]{2,}|s|xn--[a-z0-9]{2,})))',
        // ICANN e-mail test (http://idn.icann.org/E-mail_test)
        icann_domains = [
            '\\u0645\\u062b\\u0627\\u0644\\x2e\\u0625\\u062e\\u062a\\u0628\\u0627\\u0631',
            '\\u4f8b\\u5b50\\x2e\\u6d4b\\u8bd5',
            '\\u4f8b\\u5b50\\x2e\\u6e2c\\u8a66',
            '\\u03c0\\u03b1\\u03c1\\u03ac\\u03b4\\u03b5\\u03b9\\u03b3\\u03bc\\u03b1\\x2e\\u03b4\\u03bf\\u03ba\\u03b9\\u03bc\\u03ae',
            '\\u0909\\u0926\\u093e\\u0939\\u0930\\u0923\\x2e\\u092a\\u0930\\u0940\\u0915\\u094d\\u0937\\u093e',
            '\\u4f8b\\u3048\\x2e\\u30c6\\u30b9\\u30c8',
            '\\uc2e4\\ub840\\x2e\\ud14c\\uc2a4\\ud2b8',
            '\\u0645\\u062b\\u0627\\u0644\\x2e\\u0622\\u0632\\u0645\\u0627\\u06cc\\u0634\\u06cc',
            '\\u043f\\u0440\\u0438\\u043c\\u0435\\u0440\\x2e\\u0438\\u0441\\u043f\\u044b\\u0442\\u0430\\u043d\\u0438\\u0435',
            '\\u0b89\\u0ba4\\u0bbe\\u0bb0\\u0ba3\\u0bae\\u0bcd\\x2e\\u0baa\\u0bb0\\u0bbf\\u0b9f\\u0bcd\\u0b9a\\u0bc8',
            '\\u05d1\\u05f2\\u05b7\\u05e9\\u05e4\\u05bc\\u05d9\\u05dc\\x2e\\u05d8\\u05e2\\u05e1\\u05d8',
        ],
        icann_addr = 'mailtest\\x40(' + icann_domains.join('|') + ')',
        word = strict ? '(' + atom + '|' + quoted_string + ')' : '[^\\u0000-\\u0020\\u002e\\u00a0\\u0040\\u007f\\u2028\\u2029]+',
        delim = '[,;\\s\\n]',
        local_part = word + '(\\x2e' + word + ')*',
        addr_spec = '((' + local_part + '\\x40' + domain + ')|(' + icann_addr + '))',
        rx_flag = count ? 'ig' : 'i',
        rx = inline ? new RegExp('(^|<|' + delim + ')' + addr_spec + '($|>|' + delim + ')', rx_flag) : new RegExp('^' + addr_spec + '$', 'i');

    if (count) {
        var re = input.match(rx);
        return re ? re.length : 0;
    }

    return rx.test(input);
}

// recursively copy an object
function rcube_clone_object(obj) {
    var out = {};

    for (var key in obj) {
        if (obj[key] && typeof obj[key] === 'object') {
            out[key] = rcube_clone_object(obj[key]);
        } else {
            out[key] = obj[key];
        }
    }

    return out;
}

// make a string URL safe (and compatible with PHP's rawurlencode())
function urlencode(str) {
    return encodeURIComponent(str)
        .replace('*', '%2A')
        .replace('(', '%28')
        .replace(')', '%29')
        .replace('!', '%21')
        .replace("'", '%27');
}


// get any type of html objects by id/name
function rcube_find_object(id, d) {
    var n, f, obj, e;

    if (!d) {
        d = document;
    }

    if (d.getElementById) {
        if (obj = d.getElementById(id)) {
            return obj;
        }
    }

    if (!obj && d.getElementsByName && (e = d.getElementsByName(id))) {
        obj = e[0];
    }

    if (!obj && d.all) {
        obj = d.all[id];
    }

    if (!obj && d.images.length) {
        obj = d.images[id];
    }

    if (!obj && d.forms.length) {
        for (f = 0; f < d.forms.length; f++) {
            if (d.forms[f].name == id) {
                obj = d.forms[f];
            } else if (d.forms[f].elements[id]) {
                obj = d.forms[f].elements[id];
            }
        }
    }

    if (!obj && d.layers) {
        if (d.layers[id]) {
            obj = d.layers[id];
        }
        for (n = 0; !obj && n < d.layers.length; n++) {
            obj = rcube_find_object(id, d.layers[n].document);
        }
    }

    return obj;
}

// determine whether the mouse is over the given object or not
function rcube_mouse_is_over(ev, obj) {
    var mouse = rcube_event.get_mouse_pos(ev),
        pos = $(obj).offset();

    return (mouse.x >= pos.left) && (mouse.x < (pos.left + obj.offsetWidth))
    && (mouse.y >= pos.top) && (mouse.y < (pos.top + obj.offsetHeight));
}


// cookie functions by GoogieSpell
function setCookie(name, value, expires, path, domain, secure) {
    var curCookie = name + '=' + escape(value)
      + (expires ? '; expires=' + expires.toGMTString() : '')
      + (path ? '; path=' + path : '')
      + (domain ? '; domain=' + domain : '')
      + (secure ? '; secure' : '') + '; SameSite=Lax';

    document.cookie = curCookie;
}

function getCookie(name) {
    var dc = document.cookie,
        prefix = name + '=',
        begin = dc.indexOf('; ' + prefix);

    if (begin == -1) {
        begin = dc.indexOf(prefix);
        if (begin != 0) {
            return null;
        }
    } else {
        begin += 2;
    }

    var end = dc.indexOf(';', begin);
    if (end == -1) {
        end = dc.length;
    }

    return unescape(dc.substring(begin + prefix.length, end));
}

// deprecated aliases, to be removed, use rcmail.set_cookie/rcmail.get_cookie
roundcube_browser.prototype.set_cookie = setCookie;
roundcube_browser.prototype.get_cookie = getCookie;

var bw = new roundcube_browser();
bw.set_html_class();


// Add escape() method to RegExp object
// http://dev.rubyonrails.org/changeset/7271
RegExp.escape = function (str) {
    return String(str).replace(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1');
};

// Extend Date prototype to detect Standard timezone without DST
// from http://www.michaelapproved.com/articles/timezone-detect-and-ignore-daylight-saving-time-dst/
Date.prototype.getStdTimezoneOffset = function () {
    var m = 12,
        d = new Date(null, m, 1),
        tzo = d.getTimezoneOffset();

    while (--m) {
        d.setUTCMonth(m);
        if (tzo != d.getTimezoneOffset()) {
            return Math.max(tzo, d.getTimezoneOffset());
        }
    }

    return tzo;
};

// define String's startsWith() method for old browsers
if (!String.prototype.startsWith) {
    String.prototype.startsWith = function (search, position) {
        position = position || 0;
        return this.slice(position, search.length) === search;
    };
}

if (!String.prototype.endsWith) {
    String.prototype.endsWith = function (searchString, position) {
        var subjectString = this.toString();
        if (typeof position !== 'number' || !isFinite(position) || Math.floor(position) !== position || position > subjectString.length) {
            position = subjectString.length;
        }
        position -= searchString.length;
        var lastIndex = subjectString.lastIndexOf(searchString, position);
        return lastIndex !== -1 && lastIndex === position;
    };
}

// array utility function
jQuery.last = function (arr) {
    return arr && arr.length ? arr[arr.length - 1] : undefined;
};

// jQuery plugin to set HTML5 placeholder and title attributes on input elements
jQuery.fn.placeholder = function (text) {
    return this.each(function () {
        $(this).prop({ title: text, placeholder: text });
    });
};

// function to parse query string into an object
var rcube_parse_query = function (query) {
    if (!query) {
        return {};
    }

    var params = {}, e, k, v,
        re = /([^&=]+)=?([^&]*)/g,
        decodeRE = /\+/g, // Regex for replacing addition symbol with a space
        decode = function (str) {
            return decodeURIComponent(str.replace(decodeRE, ' '));
        };

    query = query.replace(/\?/, '');

    while (e = re.exec(query)) {
        k = decode(e[1]);
        v = decode(e[2]);

        if (k.substring(k.length - 2) === '[]') {
            k = k.substring(0, k.length - 2);
            (params[k] || (params[k] = [])).push(v);
        } else {
            params[k] = v;
        }
    }

    return params;
};


// Base64 code from Tyler Akins -- https://rumkin.com
var Base64 = (function () {
    var keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

    // private method for UTF-8 encoding
    var utf8_encode = function (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
    var utf8_decode = function (utftext) {
        var i = 0, string = '', 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;
    };

    var obj = {
    /**
     * Encodes a string in base64
     * @param {String} input The string to encode in base64.
     */
        encode: function (input) {
            // encode UTF8 as btoa() may fail on some characters
            input = utf8_encode(input);

            if (typeof (window.btoa) === 'function') {
                try {
                    return btoa(input);
                } catch (e) {}
            }

            var chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0, output = '', len = input.length;

            while (i < len) {
                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;
        },

        /**
         * Decodes a base64 string.
         * @param {String} input The string to decode.
         */
        decode: function (input) {
            if (typeof (window.atob) === 'function') {
                try {
                    return utf8_decode(atob(input));
                } catch (e) {}
            }

            var chr1, chr2, chr3, enc1, enc2, enc3, enc4, len, i = 0, output = '';

            // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
            input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '');
            len = input.length;

            while (i < len) {
                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);
                }
            }

            return utf8_decode(output);
        },
    };

    return obj;
})();
