
// Copyright 2009-2012 by contributors, MIT License
// vim: ts=4 sts=4 sw=4 expandtab

//Add semicolon to prevent IIFE from being passed as argument to concated code.
;
// Module systems magic dance
(function (definition) {
    // RequireJS
    if (typeof define == "function") {
        define(definition);
        // YUI3
    } else if (typeof YUI == "function") {
        YUI.add("es5", definition);
        // CommonJS and <script>
    } else {
        definition();
    }
})(function () {

    /**
     * Brings an environment as close to ECMAScript 5 compliance
     * as is possible with the facilities of erstwhile engines.
     *
     * Annotated ES5: http://es5.github.com/ (specific links below)
     * ES5 Spec: http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf
     * Required reading: http://javascriptweblog.wordpress.com/2011/12/05/extending-javascript-natives/
     */

//
// Function
// ========
//

// ES-5 15.3.4.5
// http://es5.github.com/#x15.3.4.5

    function Empty() {}

    if (!Function.prototype.bind) {
        Function.prototype.bind = function bind(that) { // .length is 1
            // 1. Let Target be the this value.
            var target = this;
            // 2. If IsCallable(Target) is false, throw a TypeError exception.
            if (typeof target != "function") {
                throw new TypeError("Function.prototype.bind called on incompatible " + target);
            }
            // 3. Let A be a new (possibly empty) internal list of all of the
            //   argument values provided after thisArg (arg1, arg2 etc), in order.
            // XXX slicedArgs will stand in for "A" if used
            var args = _Array_slice_.call(arguments, 1); // for normal call
            // 4. Let F be a new native ECMAScript object.
            // 11. Set the [[Prototype]] internal property of F to the standard
            //   built-in Function prototype object as specified in 15.3.3.1.
            // 12. Set the [[Call]] internal property of F as described in
            //   15.3.4.5.1.
            // 13. Set the [[Construct]] internal property of F as described in
            //   15.3.4.5.2.
            // 14. Set the [[HasInstance]] internal property of F as described in
            //   15.3.4.5.3.
            var binder = function () {

                if (this instanceof bound) {
                    // 15.3.4.5.2 [[Construct]]
                    // When the [[Construct]] internal method of a function object,
                    // F that was created using the bind function is called with a
                    // list of arguments ExtraArgs, the following steps are taken:
                    // 1. Let target be the value of F's [[TargetFunction]]
                    //   internal property.
                    // 2. If target has no [[Construct]] internal method, a
                    //   TypeError exception is thrown.
                    // 3. Let boundArgs be the value of F's [[BoundArgs]] internal
                    //   property.
                    // 4. Let args be a new list containing the same values as the
                    //   list boundArgs in the same order followed by the same
                    //   values as the list ExtraArgs in the same order.
                    // 5. Return the result of calling the [[Construct]] internal
                    //   method of target providing args as the arguments.

                    var result = target.apply(
                        this,
                        args.concat(_Array_slice_.call(arguments))
                    );
                    if (Object(result) === result) {
                        return result;
                    }
                    return this;

                } else {
                    // 15.3.4.5.1 [[Call]]
                    // When the [[Call]] internal method of a function object, F,
                    // which was created using the bind function is called with a
                    // this value and a list of arguments ExtraArgs, the following
                    // steps are taken:
                    // 1. Let boundArgs be the value of F's [[BoundArgs]] internal
                    //   property.
                    // 2. Let boundThis be the value of F's [[BoundThis]] internal
                    //   property.
                    // 3. Let target be the value of F's [[TargetFunction]] internal
                    //   property.
                    // 4. Let args be a new list containing the same values as the
                    //   list boundArgs in the same order followed by the same
                    //   values as the list ExtraArgs in the same order.
                    // 5. Return the result of calling the [[Call]] internal method
                    //   of target providing boundThis as the this value and
                    //   providing args as the arguments.

                    // equiv: target.call(this, ...boundArgs, ...args)
                    return target.apply(
                        that,
                        args.concat(_Array_slice_.call(arguments))
                    );

                }

            };

            // 15. If the [[Class]] internal property of Target is "Function", then
            //     a. Let L be the length property of Target minus the length of A.
            //     b. Set the length own property of F to either 0 or L, whichever is
            //       larger.
            // 16. Else set the length own property of F to 0.

            var boundLength = Math.max(0, target.length - args.length);

            // 17. Set the attributes of the length own property of F to the values
            //   specified in 15.3.5.1.
            var boundArgs = [];
            for (var i = 0; i < boundLength; i++) {
                boundArgs.push("$" + i);
            }

            // XXX Build a dynamic function with desired amount of arguments is the only
            // way to set the length property of a function.
            // In environments where Content Security Policies enabled (Chrome extensions,
            // for ex.) all use of eval or Function costructor throws an exception.
            // However in all of these environments Function.prototype.bind exists
            // and so this code will never be executed.
            var bound = Function("binder", "return function(" + boundArgs.join(",") + "){return binder.apply(this,arguments)}")(binder);

            if (target.prototype) {
                Empty.prototype = target.prototype;
                bound.prototype = new Empty();
                // Clean up dangling references.
                Empty.prototype = null;
            }

            // TODO
            // 18. Set the [[Extensible]] internal property of F to true.

            // TODO
            // 19. Let thrower be the [[ThrowTypeError]] function Object (13.2.3).
            // 20. Call the [[DefineOwnProperty]] internal method of F with
            //   arguments "caller", PropertyDescriptor {[[Get]]: thrower, [[Set]]:
            //   thrower, [[Enumerable]]: false, [[Configurable]]: false}, and
            //   false.
            // 21. Call the [[DefineOwnProperty]] internal method of F with
            //   arguments "arguments", PropertyDescriptor {[[Get]]: thrower,
            //   [[Set]]: thrower, [[Enumerable]]: false, [[Configurable]]: false},
            //   and false.

            // TODO
            // NOTE Function objects created using Function.prototype.bind do not
            // have a prototype property or the [[Code]], [[FormalParameters]], and
            // [[Scope]] internal properties.
            // XXX can't delete prototype in pure-js.

            // 22. Return F.
            return bound;
        };
    }

// Shortcut to an often accessed properties, in order to avoid multiple
// dereference that costs universally.
// _Please note: Shortcuts are defined after `Function.prototype.bind` as we
// us it in defining shortcuts.
    var call = Function.prototype.call;
    var prototypeOfArray = Array.prototype;
    var prototypeOfObject = Object.prototype;
    var _Array_slice_ = prototypeOfArray.slice;
// Having a toString local variable name breaks in Opera so use _toString.
    var _toString = call.bind(prototypeOfObject.toString);
    var owns = call.bind(prototypeOfObject.hasOwnProperty);

// If JS engine supports accessors creating shortcuts.
    var defineGetter;
    var defineSetter;
    var lookupGetter;
    var lookupSetter;
    var supportsAccessors;
    if ((supportsAccessors = owns(prototypeOfObject, "__defineGetter__"))) {
        defineGetter = call.bind(prototypeOfObject.__defineGetter__);
        defineSetter = call.bind(prototypeOfObject.__defineSetter__);
        lookupGetter = call.bind(prototypeOfObject.__lookupGetter__);
        lookupSetter = call.bind(prototypeOfObject.__lookupSetter__);
    }

//
// Array
// =====
//

// ES5 15.4.4.12
// http://es5.github.com/#x15.4.4.12
// Default value for second param
// [bugfix, ielt9, old browsers]
// IE < 9 bug: [1,2].splice(0).join("") == "" but should be "12"
    if ([1,2].splice(0).length != 2) {
        var array_splice = Array.prototype.splice;
        var array_push = Array.prototype.push;
        var array_unshift = Array.prototype.unshift;

        if (function() { // test IE < 9 to splice bug - see issue #138
                function makeArray(l) {
                    var a = [];
                    while (l--) {
                        a.unshift(l)
                    }
                    return a
                }

                var array = []
                    , lengthBefore
                    ;

                array.splice.bind(array, 0, 0).apply(null, makeArray(20));
                array.splice.bind(array, 0, 0).apply(null, makeArray(26));

                lengthBefore = array.length; //20
                array.splice(5, 0, "XXX"); // add one element

                if (lengthBefore + 1 == array.length) {
                    return true;// has right splice implementation without bugs
                }
                // else {
                //    IE8 bug
                // }
            }()) {//IE 6/7
            Array.prototype.splice = function(start, deleteCount) {
                if (!arguments.length) {
                    return [];
                } else {
                    return array_splice.apply(this, [
                        start === void 0 ? 0 : start,
                        deleteCount === void 0 ? (this.length - start) : deleteCount
                    ].concat(_Array_slice_.call(arguments, 2)))
                }
            };
        }
        else {//IE8
            Array.prototype.splice = function(start, deleteCount) {
                var result
                    , args = _Array_slice_.call(arguments, 2)
                    , addElementsCount = args.length
                    ;

                if (!arguments.length) {
                    return [];
                }

                if (start === void 0) { // default
                    start = 0;
                }
                if (deleteCount === void 0) { // default
                    deleteCount = this.length - start;
                }

                if (addElementsCount > 0) {
                    if (deleteCount <= 0) {
                        if (start == this.length) { // tiny optimisation #1
                            array_push.apply(this, args);
                            return [];
                        }

                        if (start == 0) { // tiny optimisation #2
                            array_unshift.apply(this, args);
                            return [];
                        }
                    }

                    // Array.prototype.splice implementation
                    result = _Array_slice_.call(this, start, start + deleteCount);// delete part
                    args.push.apply(args, _Array_slice_.call(this, start + deleteCount, this.length));// right part
                    args.unshift.apply(args, _Array_slice_.call(this, 0, start));// left part

                    // delete all items from this array and replace it to 'left part' + _Array_slice_.call(arguments, 2) + 'right part'
                    args.unshift(0, this.length);

                    array_splice.apply(this, args);

                    return result;
                }

                return array_splice.call(this, start, deleteCount);
            }

        }
    }

// ES5 15.4.4.12
// http://es5.github.com/#x15.4.4.13
// Return len+argCount.
// [bugfix, ielt8]
// IE < 8 bug: [].unshift(0) == undefined but should be "1"
    if ([].unshift(0) != 1) {
        var array_unshift = Array.prototype.unshift;
        Array.prototype.unshift = function() {
            array_unshift.apply(this, arguments);
            return this.length;
        };
    }

// ES5 15.4.3.2
// http://es5.github.com/#x15.4.3.2
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/isArray
    if (!Array.isArray) {
        Array.isArray = function isArray(obj) {
            return _toString(obj) == "[object Array]";
        };
    }

// The IsCallable() check in the Array functions
// has been replaced with a strict check on the
// internal class of the object to trap cases where
// the provided function was actually a regular
// expression literal, which in V8 and
// JavaScriptCore is a typeof "function".  Only in
// V8 are regular expression literals permitted as
// reduce parameters, so it is desirable in the
// general case for the shim to match the more
// strict and common behavior of rejecting regular
// expressions.

// ES5 15.4.4.18
// http://es5.github.com/#x15.4.4.18
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/array/forEach

// Check failure of by-index access of string characters (IE < 9)
// and failure of `0 in boxedString` (Rhino)
    var boxedString = Object("a"),
        splitString = boxedString[0] != "a" || !(0 in boxedString);
// Check node 0.6.21 bug where third parameter is not boxed
    var boxedForEach = true;
    if (Array.prototype.forEach) {
        Array.prototype.forEach.call("foo", function(item, i, obj) {
            if (typeof obj !== 'object') boxedForEach = false;
        });
    }

    if (!Array.prototype.forEach || !boxedForEach) {
        Array.prototype.forEach = function forEach(fun /*, thisp*/) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                thisp = arguments[1],
                i = -1,
                length = self.length >>> 0;

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(); // TODO message
            }

            while (++i < length) {
                if (i in self) {
                    // Invoke the callback function with call, passing arguments:
                    // context, property value, property key, thisArg object
                    // context
                    fun.call(thisp, self[i], i, object);
                }
            }
        };
    }

// ES5 15.4.4.19
// http://es5.github.com/#x15.4.4.19
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/map
    if (!Array.prototype.map) {
        Array.prototype.map = function map(fun /*, thisp*/) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0,
                result = Array(length),
                thisp = arguments[1];

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            for (var i = 0; i < length; i++) {
                if (i in self)
                    result[i] = fun.call(thisp, self[i], i, object);
            }
            return result;
        };
    }

// ES5 15.4.4.20
// http://es5.github.com/#x15.4.4.20
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/filter
    if (!Array.prototype.filter) {
        Array.prototype.filter = function filter(fun /*, thisp */) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0,
                result = [],
                value,
                thisp = arguments[1];

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            for (var i = 0; i < length; i++) {
                if (i in self) {
                    value = self[i];
                    if (fun.call(thisp, value, i, object)) {
                        result.push(value);
                    }
                }
            }
            return result;
        };
    }

// ES5 15.4.4.16
// http://es5.github.com/#x15.4.4.16
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/every
    if (!Array.prototype.every) {
        Array.prototype.every = function every(fun /*, thisp */) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0,
                thisp = arguments[1];

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            for (var i = 0; i < length; i++) {
                if (i in self && !fun.call(thisp, self[i], i, object)) {
                    return false;
                }
            }
            return true;
        };
    }

// ES5 15.4.4.17
// http://es5.github.com/#x15.4.4.17
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/some
    if (!Array.prototype.some) {
        Array.prototype.some = function some(fun /*, thisp */) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0,
                thisp = arguments[1];

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            for (var i = 0; i < length; i++) {
                if (i in self && fun.call(thisp, self[i], i, object)) {
                    return true;
                }
            }
            return false;
        };
    }

// ES5 15.4.4.21
// http://es5.github.com/#x15.4.4.21
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/reduce
    if (!Array.prototype.reduce) {
        Array.prototype.reduce = function reduce(fun /*, initial*/) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0;

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            // no value to return if no initial value and an empty array
            if (!length && arguments.length == 1) {
                throw new TypeError("reduce of empty array with no initial value");
            }

            var i = 0;
            var result;
            if (arguments.length >= 2) {
                result = arguments[1];
            } else {
                do {
                    if (i in self) {
                        result = self[i++];
                        break;
                    }

                    // if array contains no values, no initial value to return
                    if (++i >= length) {
                        throw new TypeError("reduce of empty array with no initial value");
                    }
                } while (true);
            }

            for (; i < length; i++) {
                if (i in self) {
                    result = fun.call(void 0, result, self[i], i, object);
                }
            }

            return result;
        };
    }

// ES5 15.4.4.22
// http://es5.github.com/#x15.4.4.22
// https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/reduceRight
    if (!Array.prototype.reduceRight) {
        Array.prototype.reduceRight = function reduceRight(fun /*, initial*/) {
            var object = toObject(this),
                self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    object,
                length = self.length >>> 0;

            // If no callback function or if callback is not a callable function
            if (_toString(fun) != "[object Function]") {
                throw new TypeError(fun + " is not a function");
            }

            // no value to return if no initial value, empty array
            if (!length && arguments.length == 1) {
                throw new TypeError("reduceRight of empty array with no initial value");
            }

            var result, i = length - 1;
            if (arguments.length >= 2) {
                result = arguments[1];
            } else {
                do {
                    if (i in self) {
                        result = self[i--];
                        break;
                    }

                    // if array contains no values, no initial value to return
                    if (--i < 0) {
                        throw new TypeError("reduceRight of empty array with no initial value");
                    }
                } while (true);
            }

            if (i < 0) {
                return result;
            }

            do {
                if (i in this) {
                    result = fun.call(void 0, result, self[i], i, object);
                }
            } while (i--);

            return result;
        };
    }

// ES5 15.4.4.14
// http://es5.github.com/#x15.4.4.14
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/indexOf
    if (!Array.prototype.indexOf || ([0, 1].indexOf(1, 2) != -1)) {
        Array.prototype.indexOf = function indexOf(sought /*, fromIndex */ ) {
            var self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    toObject(this),
                length = self.length >>> 0;

            if (!length) {
                return -1;
            }

            var i = 0;
            if (arguments.length > 1) {
                i = toInteger(arguments[1]);
            }

            // handle negative indices
            i = i >= 0 ? i : Math.max(0, length + i);
            for (; i < length; i++) {
                if (i in self && self[i] === sought) {
                    return i;
                }
            }
            return -1;
        };
    }

// ES5 15.4.4.15
// http://es5.github.com/#x15.4.4.15
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/lastIndexOf
    if (!Array.prototype.lastIndexOf || ([0, 1].lastIndexOf(0, -3) != -1)) {
        Array.prototype.lastIndexOf = function lastIndexOf(sought /*, fromIndex */) {
            var self = splitString && _toString(this) == "[object String]" ?
                    this.split("") :
                    toObject(this),
                length = self.length >>> 0;

            if (!length) {
                return -1;
            }
            var i = length - 1;
            if (arguments.length > 1) {
                i = Math.min(i, toInteger(arguments[1]));
            }
            // handle negative indices
            i = i >= 0 ? i : length - Math.abs(i);
            for (; i >= 0; i--) {
                if (i in self && sought === self[i]) {
                    return i;
                }
            }
            return -1;
        };
    }

//
// Object
// ======
//

// ES5 15.2.3.14
// http://es5.github.com/#x15.2.3.14
    if (!Object.keys) {
        // http://whattheheadsaid.com/2010/10/a-safer-object-keys-compatibility-implementation
        var hasDontEnumBug = true,
            dontEnums = [
                "toString",
                "toLocaleString",
                "valueOf",
                "hasOwnProperty",
                "isPrototypeOf",
                "propertyIsEnumerable",
                "constructor"
            ],
            dontEnumsLength = dontEnums.length;

        for (var key in {"toString": null}) {
            hasDontEnumBug = false;
        }

        Object.keys = function keys(object) {

            if (
                (typeof object != "object" && typeof object != "function") ||
                object === null
            ) {
                throw new TypeError("Object.keys called on a non-object");
            }

            var keys = [];
            for (var name in object) {
                if (owns(object, name)) {
                    keys.push(name);
                }
            }

            if (hasDontEnumBug) {
                for (var i = 0, ii = dontEnumsLength; i < ii; i++) {
                    var dontEnum = dontEnums[i];
                    if (owns(object, dontEnum)) {
                        keys.push(dontEnum);
                    }
                }
            }
            return keys;
        };

    }

//
// Date
// ====
//

// ES5 15.9.5.43
// http://es5.github.com/#x15.9.5.43
// This function returns a String value represent the instance in time
// represented by this Date object. The format of the String is the Date Time
// string format defined in 15.9.1.15. All fields are present in the String.
// The time zone is always UTC, denoted by the suffix Z. If the time value of
// this object is not a finite Number a RangeError exception is thrown.
    var negativeDate = -62198755200000,
        negativeYearString = "-000001";
    if (
        !Date.prototype.toISOString ||
        (new Date(negativeDate).toISOString().indexOf(negativeYearString) === -1)
    ) {
        Date.prototype.toISOString = function toISOString() {
            var result, length, value, year, month;
            if (!isFinite(this)) {
                throw new RangeError("Date.prototype.toISOString called on non-finite value.");
            }

            year = this.getUTCFullYear();

            month = this.getUTCMonth();
            // see https://github.com/kriskowal/es5-shim/issues/111
            year += Math.floor(month / 12);
            month = (month % 12 + 12) % 12;

            // the date time string format is specified in 15.9.1.15.
            result = [month + 1, this.getUTCDate(),
                this.getUTCHours(), this.getUTCMinutes(), this.getUTCSeconds()];
            year = (
            (year < 0 ? "-" : (year > 9999 ? "+" : "")) +
            ("00000" + Math.abs(year))
                .slice(0 <= year && year <= 9999 ? -4 : -6)
            );

            length = result.length;
            while (length--) {
                value = result[length];
                // pad months, days, hours, minutes, and seconds to have two
                // digits.
                if (value < 10) {
                    result[length] = "0" + value;
                }
            }
            // pad milliseconds to have three digits.
            return (
            year + "-" + result.slice(0, 2).join("-") +
            "T" + result.slice(2).join(":") + "." +
            ("000" + this.getUTCMilliseconds()).slice(-3) + "Z"
            );
        };
    }


// ES5 15.9.5.44
// http://es5.github.com/#x15.9.5.44
// This function provides a String representation of a Date object for use by
// JSON.stringify (15.12.3).
    var dateToJSONIsSupported = false;
    try {
        dateToJSONIsSupported = (
        Date.prototype.toJSON &&
        new Date(NaN).toJSON() === null &&
        new Date(negativeDate).toJSON().indexOf(negativeYearString) !== -1 &&
        Date.prototype.toJSON.call({ // generic
            toISOString: function () {
                return true;
            }
        })
        );
    } catch (e) {
    }
    if (!dateToJSONIsSupported) {
        Date.prototype.toJSON = function toJSON(key) {
            // When the toJSON method is called with argument key, the following
            // steps are taken:

            // 1.  Let O be the result of calling ToObject, giving it the this
            // value as its argument.
            // 2. Let tv be toPrimitive(O, hint Number).
            var o = Object(this),
                tv = toPrimitive(o),
                toISO;
            // 3. If tv is a Number and is not finite, return null.
            if (typeof tv === "number" && !isFinite(tv)) {
                return null;
            }
            // 4. Let toISO be the result of calling the [[Get]] internal method of
            // O with argument "toISOString".
            toISO = o.toISOString;
            // 5. If IsCallable(toISO) is false, throw a TypeError exception.
            if (typeof toISO != "function") {
                throw new TypeError("toISOString property is not callable");
            }
            // 6. Return the result of calling the [[Call]] internal method of
            //  toISO with O as the this value and an empty argument list.
            return toISO.call(o);

            // NOTE 1 The argument is ignored.

            // NOTE 2 The toJSON function is intentionally generic; it does not
            // require that its this value be a Date object. Therefore, it can be
            // transferred to other kinds of objects for use as a method. However,
            // it does require that any such object have a toISOString method. An
            // object is free to use the argument key to filter its
            // stringification.
        };
    }

// ES5 15.9.4.2
// http://es5.github.com/#x15.9.4.2
// based on work shared by Daniel Friesen (dantman)
// http://gist.github.com/303249
    if (!Date.parse || "Date.parse is buggy") {
        // XXX global assignment won't work in embeddings that use
        // an alternate object for the context.
        Date = (function(NativeDate) {

            // Date.length === 7
            function Date(Y, M, D, h, m, s, ms) {
                var length = arguments.length;
                if (this instanceof NativeDate) {
                    var date = length == 1 && String(Y) === Y ? // isString(Y)
                        // We explicitly pass it through parse:
                        new NativeDate(Date.parse(Y)) :
                        // We have to manually make calls depending on argument
                        // length here
                        length >= 7 ? new NativeDate(Y, M, D, h, m, s, ms) :
                            length >= 6 ? new NativeDate(Y, M, D, h, m, s) :
                                length >= 5 ? new NativeDate(Y, M, D, h, m) :
                                    length >= 4 ? new NativeDate(Y, M, D, h) :
                                        length >= 3 ? new NativeDate(Y, M, D) :
                                            length >= 2 ? new NativeDate(Y, M) :
                                                length >= 1 ? new NativeDate(Y) :
                                                    new NativeDate();
                    // Prevent mixups with unfixed Date object
                    date.constructor = Date;
                    return date;
                }
                return NativeDate.apply(this, arguments);
            };

            // 15.9.1.15 Date Time String Format.
            var isoDateExpression = new RegExp("^" +
            "(\\d{4}|[\+\-]\\d{6})" + // four-digit year capture or sign +
                                      // 6-digit extended year
            "(?:-(\\d{2})" + // optional month capture
            "(?:-(\\d{2})" + // optional day capture
            "(?:" + // capture hours:minutes:seconds.milliseconds
            "T(\\d{2})" + // hours capture
            ":(\\d{2})" + // minutes capture
            "(?:" + // optional :seconds.milliseconds
            ":(\\d{2})" + // seconds capture
            "(?:(\\.\\d{1,}))?" + // milliseconds capture
            ")?" +
            "(" + // capture UTC offset component
            "Z|" + // UTC capture
            "(?:" + // offset specifier +/-hours:minutes
            "([-+])" + // sign capture
            "(\\d{2})" + // hours offset capture
            ":(\\d{2})" + // minutes offset capture
            ")" +
            ")?)?)?)?" +
            "$");

            var months = [
                0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
            ];

            function dayFromMonth(year, month) {
                var t = month > 1 ? 1 : 0;
                return (
                months[month] +
                Math.floor((year - 1969 + t) / 4) -
                Math.floor((year - 1901 + t) / 100) +
                Math.floor((year - 1601 + t) / 400) +
                365 * (year - 1970)
                );
            }

            function toUTC(t) {
                return Number(new NativeDate(1970, 0, 1, 0, 0, 0, t));
            }

            // Copy any custom methods a 3rd party library may have added
            for (var key in NativeDate) {
                Date[key] = NativeDate[key];
            }

            // Copy "native" methods explicitly; they may be non-enumerable
            Date.now = NativeDate.now;
            Date.UTC = NativeDate.UTC;
            Date.prototype = NativeDate.prototype;
            Date.prototype.constructor = Date;

            // Upgrade Date.parse to handle simplified ISO 8601 strings
            Date.parse = function parse(string) {
                var match = isoDateExpression.exec(string);
                if (match) {
                    // parse months, days, hours, minutes, seconds, and milliseconds
                    // provide default values if necessary
                    // parse the UTC offset component
                    var year = Number(match[1]),
                        month = Number(match[2] || 1) - 1,
                        day = Number(match[3] || 1) - 1,
                        hour = Number(match[4] || 0),
                        minute = Number(match[5] || 0),
                        second = Number(match[6] || 0),
                        millisecond = Math.floor(Number(match[7] || 0) * 1000),
                    // When time zone is missed, local offset should be used
                    // (ES 5.1 bug)
                    // see https://bugs.ecmascript.org/show_bug.cgi?id=112
                        isLocalTime = Boolean(match[4] && !match[8]),
                        signOffset = match[9] === "-" ? 1 : -1,
                        hourOffset = Number(match[10] || 0),
                        minuteOffset = Number(match[11] || 0),
                        result;
                    if (
                        hour < (
                            minute > 0 || second > 0 || millisecond > 0 ?
                                24 : 25
                        ) &&
                        minute < 60 && second < 60 && millisecond < 1000 &&
                        month > -1 && month < 12 && hourOffset < 24 &&
                        minuteOffset < 60 && // detect invalid offsets
                        day > -1 &&
                        day < (
                        dayFromMonth(year, month + 1) -
                        dayFromMonth(year, month)
                        )
                    ) {
                        result = (
                        (dayFromMonth(year, month) + day) * 24 +
                        hour +
                        hourOffset * signOffset
                        ) * 60;
                        result = (
                        (result + minute + minuteOffset * signOffset) * 60 +
                        second
                        ) * 1000 + millisecond;
                        if (isLocalTime) {
                            result = toUTC(result);
                        }
                        if (-8.64e15 <= result && result <= 8.64e15) {
                            return result;
                        }
                    }
                    return NaN;
                }
                return NativeDate.parse.apply(this, arguments);
            };

            return Date;
        })(Date);
    }

// ES5 15.9.4.4
// http://es5.github.com/#x15.9.4.4
    if (!Date.now) {
        Date.now = function now() {
            return new Date().getTime();
        };
    }


//
// Number
// ======
//

// ES5.1 15.7.4.5
// http://es5.github.com/#x15.7.4.5
    if (!Number.prototype.toFixed || (0.00008).toFixed(3) !== '0.000' || (0.9).toFixed(0) === '0' || (1.255).toFixed(2) !== '1.25' || (1000000000000000128).toFixed(0) !== "1000000000000000128") {
        // Hide these variables and functions
        (function () {
            var base, size, data, i;

            base = 1e7;
            size = 6;
            data = [0, 0, 0, 0, 0, 0];

            function multiply(n, c) {
                var i = -1;
                while (++i < size) {
                    c += n * data[i];
                    data[i] = c % base;
                    c = Math.floor(c / base);
                }
            }

            function divide(n) {
                var i = size, c = 0;
                while (--i >= 0) {
                    c += data[i];
                    data[i] = Math.floor(c / n);
                    c = (c % n) * base;
                }
            }

            function toString() {
                var i = size;
                var s = '';
                while (--i >= 0) {
                    if (s !== '' || i === 0 || data[i] !== 0) {
                        var t = String(data[i]);
                        if (s === '') {
                            s = t;
                        } else {
                            s += '0000000'.slice(0, 7 - t.length) + t;
                        }
                    }
                }
                return s;
            }

            function pow(x, n, acc) {
                return (n === 0 ? acc : (n % 2 === 1 ? pow(x, n - 1, acc * x) : pow(x * x, n / 2, acc)));
            }

            function log(x) {
                var n = 0;
                while (x >= 4096) {
                    n += 12;
                    x /= 4096;
                }
                while (x >= 2) {
                    n += 1;
                    x /= 2;
                }
                return n;
            }

            Number.prototype.toFixed = function (fractionDigits) {
                var f, x, s, m, e, z, j, k;

                // Test for NaN and round fractionDigits down
                f = Number(fractionDigits);
                f = f !== f ? 0 : Math.floor(f);

                if (f < 0 || f > 20) {
                    throw new RangeError("Number.toFixed called with invalid number of decimals");
                }

                x = Number(this);

                // Test for NaN
                if (x !== x) {
                    return "NaN";
                }

                // If it is too big or small, return the string value of the number
                if (x <= -1e21 || x >= 1e21) {
                    return String(x);
                }

                s = "";

                if (x < 0) {
                    s = "-";
                    x = -x;
                }

                m = "0";

                if (x > 1e-21) {
                    // 1e-21 < x < 1e21
                    // -70 < log2(x) < 70
                    e = log(x * pow(2, 69, 1)) - 69;
                    z = (e < 0 ? x * pow(2, -e, 1) : x / pow(2, e, 1));
                    z *= 0x10000000000000; // Math.pow(2, 52);
                    e = 52 - e;

                    // -18 < e < 122
                    // x = z / 2 ^ e
                    if (e > 0) {
                        multiply(0, z);
                        j = f;

                        while (j >= 7) {
                            multiply(1e7, 0);
                            j -= 7;
                        }

                        multiply(pow(10, j, 1), 0);
                        j = e - 1;

                        while (j >= 23) {
                            divide(1 << 23);
                            j -= 23;
                        }

                        divide(1 << j);
                        multiply(1, 1);
                        divide(2);
                        m = toString();
                    } else {
                        multiply(0, z);
                        multiply(1 << (-e), 0);
                        m = toString() + '0.00000000000000000000'.slice(2, 2 + f);
                    }
                }

                if (f > 0) {
                    k = m.length;

                    if (k <= f) {
                        m = s + '0.0000000000000000000'.slice(0, f - k + 2) + m;
                    } else {
                        m = s + m.slice(0, k - f) + '.' + m.slice(k - f);
                    }
                } else {
                    m = s + m;
                }

                return m;
            }
        }());
    }


//
// String
// ======
//


// ES5 15.5.4.14
// http://es5.github.com/#x15.5.4.14

// [bugfix, IE lt 9, firefox 4, Konqueror, Opera, obscure browsers]
// Many browsers do not split properly with regular expressions or they
// do not perform the split correctly under obscure conditions.
// See http://blog.stevenlevithan.com/archives/cross-browser-split
// I've tested in many browsers and this seems to cover the deviant ones:
//    'ab'.split(/(?:ab)*/) should be ["", ""], not [""]
//    '.'.split(/(.?)(.?)/) should be ["", ".", "", ""], not ["", ""]
//    'tesst'.split(/(s)*/) should be ["t", undefined, "e", "s", "t"], not
//       [undefined, "t", undefined, "e", ...]
//    ''.split(/.?/) should be [], not [""]
//    '.'.split(/()()/) should be ["."], not ["", "", "."]

    var string_split = String.prototype.split;
    if (
        'ab'.split(/(?:ab)*/).length !== 2 ||
        '.'.split(/(.?)(.?)/).length !== 4 ||
        'tesst'.split(/(s)*/)[1] === "t" ||
        ''.split(/.?/).length ||
        '.'.split(/()()/).length > 1
    ) {
        (function () {
            var compliantExecNpcg = /()??/.exec("")[1] === void 0; // NPCG: nonparticipating capturing group

            String.prototype.split = function (separator, limit) {
                var string = this;
                if (separator === void 0 && limit === 0)
                    return [];

                // If `separator` is not a regex, use native split
                if (Object.prototype.toString.call(separator) !== "[object RegExp]") {
                    return string_split.apply(this, arguments);
                }

                var output = [],
                    flags = (separator.ignoreCase ? "i" : "") +
                        (separator.multiline  ? "m" : "") +
                        (separator.extended   ? "x" : "") + // Proposed for ES6
                        (separator.sticky     ? "y" : ""), // Firefox 3+
                    lastLastIndex = 0,
                // Make `global` and avoid `lastIndex` issues by working with a copy
                    separator = new RegExp(separator.source, flags + "g"),
                    separator2, match, lastIndex, lastLength;
                string += ""; // Type-convert
                if (!compliantExecNpcg) {
                    // Doesn't need flags gy, but they don't hurt
                    separator2 = new RegExp("^" + separator.source + "$(?!\\s)", flags);
                }
                /* Values for `limit`, per the spec:
                 * If undefined: 4294967295 // Math.pow(2, 32) - 1
                 * If 0, Infinity, or NaN: 0
                 * If positive number: limit = Math.floor(limit); if (limit > 4294967295) limit -= 4294967296;
                 * If negative number: 4294967296 - Math.floor(Math.abs(limit))
                 * If other: Type-convert, then use the above rules
                 */
                limit = limit === void 0 ?
                -1 >>> 0 : // Math.pow(2, 32) - 1
                limit >>> 0; // ToUint32(limit)
                while (match = separator.exec(string)) {
                    // `separator.lastIndex` is not reliable cross-browser
                    lastIndex = match.index + match[0].length;
                    if (lastIndex > lastLastIndex) {
                        output.push(string.slice(lastLastIndex, match.index));
                        // Fix browsers whose `exec` methods don't consistently return `undefined` for
                        // nonparticipating capturing groups
                        if (!compliantExecNpcg && match.length > 1) {
                            match[0].replace(separator2, function () {
                                for (var i = 1; i < arguments.length - 2; i++) {
                                    if (arguments[i] === void 0) {
                                        match[i] = void 0;
                                    }
                                }
                            });
                        }
                        if (match.length > 1 && match.index < string.length) {
                            Array.prototype.push.apply(output, match.slice(1));
                        }
                        lastLength = match[0].length;
                        lastLastIndex = lastIndex;
                        if (output.length >= limit) {
                            break;
                        }
                    }
                    if (separator.lastIndex === match.index) {
                        separator.lastIndex++; // Avoid an infinite loop
                    }
                }
                if (lastLastIndex === string.length) {
                    if (lastLength || !separator.test("")) {
                        output.push("");
                    }
                } else {
                    output.push(string.slice(lastLastIndex));
                }
                return output.length > limit ? output.slice(0, limit) : output;
            };
        }());

// [bugfix, chrome]
// If separator is undefined, then the result array contains just one String,
// which is the this value (converted to a String). If limit is not undefined,
// then the output array is truncated so that it contains no more than limit
// elements.
// "0".split(undefined, 0) -> []
    } else if ("0".split(void 0, 0).length) {
        String.prototype.split = function(separator, limit) {
            if (separator === void 0 && limit === 0) return [];
            return string_split.apply(this, arguments);
        }
    }


// ECMA-262, 3rd B.2.3
// Note an ECMAScript standart, although ECMAScript 3rd Edition has a
// non-normative section suggesting uniform semantics and it should be
// normalized across all browsers
// [bugfix, IE lt 9] IE < 9 substr() with negative value not working in IE
    if ("".substr && "0b".substr(-1) !== "b") {
        var string_substr = String.prototype.substr;
        /**
         *  Get the substring of a string
         *  @param  {integer}  start   where to start the substring
         *  @param  {integer}  length  how many characters to return
         *  @return {string}
         */
        String.prototype.substr = function(start, length) {
            return string_substr.call(
                this,
                start < 0 ? ((start = this.length + start) < 0 ? 0 : start) : start,
                length
            );
        }
    }

// ES5 15.5.4.20
// http://es5.github.com/#x15.5.4.20
    var ws = "\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003" +
        "\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028" +
        "\u2029\uFEFF";
    if (!String.prototype.trim || ws.trim()) {
        // http://blog.stevenlevithan.com/archives/faster-trim-javascript
        // http://perfectionkills.com/whitespace-deviations/
        ws = "[" + ws + "]";
        var trimBeginRegexp = new RegExp("^" + ws + ws + "*"),
            trimEndRegexp = new RegExp(ws + ws + "*$");
        String.prototype.trim = function trim() {
            if (this === void 0 || this === null) {
                throw new TypeError("can't convert "+this+" to object");
            }
            return String(this)
                .replace(trimBeginRegexp, "")
                .replace(trimEndRegexp, "");
        };
    }

//
// Util
// ======
//

// ES5 9.4
// http://es5.github.com/#x9.4
// http://jsperf.com/to-integer

    function toInteger(n) {
        n = +n;
        if (n !== n) { // isNaN
            n = 0;
        } else if (n !== 0 && n !== (1/0) && n !== -(1/0)) {
            n = (n > 0 || -1) * Math.floor(Math.abs(n));
        }
        return n;
    }

    function isPrimitive(input) {
        var type = typeof input;
        return (
        input === null ||
        type === "undefined" ||
        type === "boolean" ||
        type === "number" ||
        type === "string"
        );
    }

    function toPrimitive(input) {
        var val, valueOf, toString;
        if (isPrimitive(input)) {
            return input;
        }
        valueOf = input.valueOf;
        if (typeof valueOf === "function") {
            val = valueOf.call(input);
            if (isPrimitive(val)) {
                return val;
            }
        }
        toString = input.toString;
        if (typeof toString === "function") {
            val = toString.call(input);
            if (isPrimitive(val)) {
                return val;
            }
        }
        throw new TypeError();
    }

// ES5 9.9
// http://es5.github.com/#x9.9
    var toObject = function (o) {
        if (o == null) { // this matches both null and undefined
            throw new TypeError("can't convert "+o+" to object");
        }
        return Object(o);
    };

});