doushio/lib/es5-shim.js

/*!
 * https://github.com/es-shims/es5-shim
 * @license es5-shim Copyright 2009-2014 by contributors, MIT License
 * see https://github.com/es-shims/es5-shim/blob/master/LICENSE
 */

// vim: ts=4 sts=4 sw=4 expandtab

//Add semicolon to prevent IIFE from being passed as argument to concated code.
;

// UMD (Universal Module Definition)
// see https://github.com/umdjs/umd/blob/master/returnExports.js
(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(factory);
    } else if (typeof exports === 'object') {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like enviroments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.returnExports = factory();
  }
}(this, 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");
var splitString = boxedString[0] != "a" || !(0 in boxedString);

var properlyBoxesContext = function properlyBoxed(method) {
    // Check node 0.6.21 bug where third parameter is not boxed
    var properlyBoxes = true;
    if (method) {
        method.call('foo', function (item, index, context) {
            if (typeof context !== 'object') { properlyBoxes = false; }
        });
    }
    return !!method && properlyBoxes;
};

if (!Array.prototype.forEach || !properlyBoxesContext(Array.prototype.forEach)) {
    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 || !properlyBoxesContext(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 || !properlyBoxesContext(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 || !properlyBoxesContext(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 || !properlyBoxesContext(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 = !({'toString': null}).propertyIsEnumerable('toString'),
        hasProtoEnumBug = (function () {}).propertyIsEnumerable('prototype'),
        dontEnums = [
            "toString",
            "toLocaleString",
            "valueOf",
            "hasOwnProperty",
            "isPrototypeOf",
            "propertyIsEnumerable",
            "constructor"
        ],
        dontEnumsLength = dontEnums.length,
        isFunction = function isFunction(value) {
            return _toString(value) === '[object Function]';
        },
        isArguments = function isArguments(value) {
            var str = _toString(value);
            var isArgs = str === '[object Arguments]';
            if (!isArgs) {
                isArgs = !Array.isArray(str)
                    && value !== null
                    && typeof value === 'object'
                    && typeof value.length === 'number'
                    && value.length >= 0
                    && isFunction(value.callee);
            }
            return isArgs;
        };

    Object.keys = function keys(object) {
        var isFn = isFunction(object),
            isArgs = isArguments(object),
            isObject = object !== null && typeof object === 'object',
            isString = isObject && _toString(object) === '[object String]';

        if (!isObject && !isFn && !isArgs) {
            throw new TypeError("Object.keys called on a non-object");
        }

        var keys = [];
        var skipProto = hasProtoEnumBug && isFn;
        if (isString || isArgs) {
            for (var i = 0; i < object.length; ++i) {
                keys.push(String(i));
            }
        } else {
            for (var name in object) {
                if (!(skipProto && name === 'prototype') && owns(object, name)) {
                    keys.push(String(name));
                }
            }
        }

        if (hasDontEnumBug) {
            var ctor = object.constructor,
                skipConstructor = ctor && ctor.prototype === object;
            for (var i = 0; i < dontEnumsLength; i++) {
                var dontEnum = dontEnums[i];
                if (!(skipConstructor && dontEnum === 'constructor') && 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/es-shims/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 || isNaN(Date.parse("2000-01-01T00:00:00.000Z"))) {
    // 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
// whitespace from: http://es5.github.io/#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, "");
    };
}

// ES-5 15.1.2.2
if (parseInt(ws + '08') !== 8 || parseInt(ws + '0x16') !== 22) {
    parseInt = (function (origParseInt) {
        var hexRegex = /^0[xX]/;
        return function parseIntES5(str, radix) {
            str = String(str).trim();
            if (!+radix) {
                radix = hexRegex.test(str) ? 16 : 10;
            }
            return origParseInt(str, radix);
        };
    }(parseInt));
}

//
// 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);
};

}));