/*
 * YUI Extensions 0.33 RC2
 * Copyright(c) 2006, Jack Slocum.
 */

/**
 * @class YAHOO.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
 */
YAHOO.ext.util.JSON = new function(){
    var useHasOwn = {}.hasOwnProperty ? true : false;
    var validRE = /^("(\\.|[^"\\\n\r])*?"|[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t])+?$/;
    
    var pad = function(n) {
        return n < 10 ? '0' + n : n;
    };
    
    var m = {
        '\b': '\\b',
        '\t': '\\t',
        '\n': '\\n',
        '\f': '\\f',
        '\r': '\\r',
        '"' : '\\"',
        '\\': '\\\\'
    };

    var 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 + '"';
    };
    
    var 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" : YAHOO.ext.util.JSON.encode(v));
                        b = true;
                }
            }
            a.push(']');
            return a.join('');
    };
    
    var 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(o){
        if(typeof o == 'undefined' || o === null){
            return 'null';
        }else if(o instanceof Array){
            return encodeArray(o);
        }else if(o instanceof Date){
            return encodeDate(o);
        }else if(typeof o == 'string'){
            return encodeString(o);
        }else if(typeof o == 'number'){
            return isFinite(o) ? String(o) : "null";
        }else if(typeof o == 'boolean'){
            return String(o);
        }else {
            var a = ['{'], b, i, v;
            for (var i in o) {
                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(this.encode(i), ':',
                                v === null ? "null" : this.encode(v));
                        b = true;
                    }
                }
            }
            a.push('}');
            return a.join('');
        }
    };
    
    /**
     * Decodes (parses) a JSON string to an object. If the JSON is invalid, this function throws a SyntaxError.
     * @param {String} json The JSON string
     * @return {Object} The resulting object
     */
    this.decode = function(json){
        try{
            if(validRE.test(json)) {
                return eval('(' + json + ')');
            }
        }catch(e){
        }
        throw new SyntaxError("parseJSON");
    };
}();