/*
This file is part of Ext JS 3.4

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-04-03 15:07:25
*/
/**
 * @class Ext.util.JSON
 * Modified version of Douglas Crockford"s json.js that doesn"t
 * mess with the Object prototype
 * http://www.json.org/js.html
 * @singleton
 */
Ext.util.JSON = new (function(){
    var useHasOwn = !!{}.hasOwnProperty,
        isNative = function() {
            var useNative = null;

            return function() {
                if (useNative === null) {
                    useNative = Ext.USE_NATIVE_JSON && window.JSON && JSON.toString() == '[object JSON]';
                }
        
                return useNative;
            };
        }(),
        pad = function(n) {
            return n < 10 ? "0" + n : n;
        },
        doDecode = function(json){
            return json ? eval("(" + json + ")") : "";    
        },
        doEncode = function(o){
            if(!Ext.isDefined(o) || o === null){
                return "null";
            }else if(Ext.isArray(o)){
                return encodeArray(o);
            }else if(Ext.isDate(o)){
                return Ext.util.JSON.encodeDate(o);
            }else if(Ext.isString(o)){
                return encodeString(o);
            }else if(typeof o == "number"){
                //don't use isNumber here, since finite checks happen inside isNumber
                return isFinite(o) ? String(o) : "null";
            }else if(Ext.isBoolean(o)){
                return String(o);
            }else {
                var a = ["{"], b, i, v;
                for (i in o) {
                    // don't encode DOM objects
                    if(!o.getElementsByTagName){
                        if(!useHasOwn || o.hasOwnProperty(i)) {
                            v = o[i];
                            switch (typeof v) {
                            case "undefined":
                            case "function":
                            case "unknown":
                                break;
                            default:
                                if(b){
                                    a.push(',');
                                }
                                a.push(doEncode(i), ":",
                                        v === null ? "null" : doEncode(v));
                                b = true;
                            }
                        }
                    }
                }
                a.push("}");
                return a.join("");
            }    
        },
        m = {
            "\b": '\\b',
            "\t": '\\t',
            "\n": '\\n',
            "\f": '\\f',
            "\r": '\\r',
            '"' : '\\"',
            "\\": '\\\\'
        },
        encodeString = function(s){
            if (/["\\\x00-\x1f]/.test(s)) {
                return '"' + s.replace(/([\x00-\x1f\\"])/g, function(a, b) {
                    var c = m[b];
                    if(c){
                        return c;
                    }
                    c = b.charCodeAt();
                    return "\\u00" +
                        Math.floor(c / 16).toString(16) +
                        (c % 16).toString(16);
                }) + '"';
            }
            return '"' + s + '"';
        },
        encodeArray = function(o){
            var a = ["["], b, i, l = o.length, v;
                for (i = 0; i < l; i += 1) {
                    v = o[i];
                    switch (typeof v) {
                        case "undefined":
                        case "function":
                        case "unknown":
                            break;
                        default:
                            if (b) {
                                a.push(',');
                            }
                            a.push(v === null ? "null" : Ext.util.JSON.encode(v));
                            b = true;
                    }
                }
                a.push("]");
                return a.join("");
        };

    /**
     * <p>Encodes a Date. This returns the actual string which is inserted into the JSON string as the literal expression.
     * <b>The returned value includes enclosing double quotation marks.</b></p>
     * <p>The default return format is "yyyy-mm-ddThh:mm:ss".</p>
     * <p>To override this:</p><pre><code>
Ext.util.JSON.encodeDate = function(d) {
    return d.format('"Y-m-d"');
};
</code></pre>
     * @param {Date} d The Date to encode
     * @return {String} The string literal to use in a JSON string.
     */
    this.encodeDate = function(o){
        return '"' + o.getFullYear() + "-" +
                pad(o.getMonth() + 1) + "-" +
                pad(o.getDate()) + "T" +
                pad(o.getHours()) + ":" +
                pad(o.getMinutes()) + ":" +
                pad(o.getSeconds()) + '"';
    };

    /**
     * Encodes an Object, Array or other value
     * @param {Mixed} o The variable to encode
     * @return {String} The JSON string
     */
    this.encode = function() {
        var ec;
        return function(o) {
            if (!ec) {
                // setup encoding function on first access
                ec = isNative() ? JSON.stringify : doEncode;
            }
            return ec(o);
        };
    }();


    /**
     * Decodes (parses) a JSON string to an object. If the JSON is invalid, this function throws a SyntaxError unless the safe option is set.
     * @param {String} json The JSON string
     * @return {Object} The resulting object
     */
    this.decode = function() {
        var dc;
        return function(json) {
            if (!dc) {
                // setup decoding function on first access
                dc = isNative() ? JSON.parse : doDecode;
            }
            return dc(json);
        };
    }();

})();
/**
 * Shorthand for {@link Ext.util.JSON#encode}
 * @param {Mixed} o The variable to encode
 * @return {String} The JSON string
 * @member Ext
 * @method encode
 */
Ext.encode = Ext.util.JSON.encode;
/**
 * Shorthand for {@link Ext.util.JSON#decode}
 * @param {String} json The JSON string
 * @param {Boolean} safe (optional) Whether to return null or throw an exception if the JSON is invalid.
 * @return {Object} The resulting object
 * @member Ext
 * @method decode
 */
Ext.decode = Ext.util.JSON.decode;
