/*
    json.js

    Public Domain
    
    The global object JSON contains three methods.

    JSON.stringify(value) takes a JavaScript value and produces a JSON 
    text. The value must not be cyclical.

    JSON.parse(text) takes a JSON text and produces a JavaScript value. 
    It will throw SyntaxError if there is an error in parsing the JSON
    text. This method is fully JavaScript-based and therefore can be
    several magnitudes slower than JSON.eval. However, it is also more
    permissive than JSON.eval. For example, JSON.parse permits use of
    JavaScript-style comments in JSON text.

    JSON.eval(text) takes a JSON text and produces a JavaScript value.
    It will throw SyntaxError if there is an error in parsing the JSON
    text. JSON.eval is much faster (as it internally relies on the 
    JavaScript eval method after making safety checks) and stricter in 
    complaince to JSON text.
    
    NOTE: This implementation is hand-synchronized with the reference 
    implementation available over at http://www.json.org/json.js.
*/

/*jslint evil: true */

var JSON = function() {
    var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
        escapeable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
        meta = {   // table of character substitutions
            '\b': '\\b',
            '\t': '\\t',
            '\n': '\\n',
            '\f': '\\f',
            '\r': '\\r',
            '"' : '\\"',
            '\\': '\\\\'
        },
        s = {
            'boolean': function (x) {
                return String(x);
            },
            number: function (x) {
                return isFinite(x) ? String(x) : 'null';
            },
            string: function (x) {
                // If the string contains no control characters, no quote 
                // characters, and no backslash characters, then we can 
                // simply slap some quotes around it. Otherwise we must 
                // also replace the offending characters with safe
                // sequences.
                return escapeable.test(x) ?
                    '"' + x.replace(escapeable, function (a) {
                        var c = meta[a];
                        if (typeof c === 'string') {
                            return c;
                        }
                        return '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                    }) + '"' :
                    '"' + x + '"';
            },
            object: function (x) {
                function p(n) {
                    // Format integers to have at least two digits.
                    return n < 10 ? '0' + n : n;
                }
                if (x) {
                    var a = [], b, f, i, l, v;
                    if (x instanceof Array) {
                        a[0] = '[';
                        l = x.length;
                        for (i = 0; i < l; i += 1) {
                            v = x[i];
                            f = s[typeof v];
                            if (f) {
                                v = f(v);
                                if (typeof v === 'string') {
                                    if (b) {
                                        a[a.length] = ',';
                                    }
                                    a[a.length] = v;
                                    b = true;
                                }
                            }
                        }
                        a[a.length] = ']';
                    } else if (x instanceof Date) {
                        var tz = x.getTimezoneOffset();
                        if (tz !== 0) {
                            var tzh = Math.floor(Math.abs(tz) / 60);
                            var tzm = Math.abs(tz) % 60;
                            tz = (tz < 0 ? '+' : '-') + p(tzh) + ':' + p(tzm);
                        }
                        else {
                            tz = 'Z';
                        }
                        return '"' + 
                                x.getFullYear() + '-' +
                                p(x.getMonth() + 1) + '-' +
                                p(x.getDate()) + 'T' +
                                p(x.getHours()) + ':' +
                                p(x.getMinutes()) + ':' +
                                p(x.getSeconds()) + tz + '"';
                    } else if (x instanceof Object) {
                        a[0] = '{';
                        // Iterate through all of the keys in the 
                        // object, ignoring the proto chain and keys 
                        // that are not strings.
                        for (i in x) {
                            if (typeof i === 'string' && 
                                Object.prototype.hasOwnProperty.apply(x, [i])) {
                                v = x[i];
                                f = s[typeof v];
                                if (f) {
                                    v = f(v);
                                    if (typeof v === 'string') {
                                        if (b) {
                                            a[a.length] = ',';
                                        }
                                        a.push(s.string(i), ':', v);
                                        b = true;
                                    }
                                }
                            }
                        }
                        a[a.length] = '}';
                    } else {
                        return;
                    }
                    return a.join('');
                }
                return 'null';
            }
        };
    return {
        copyright: '(c)2005 JSON.org',
        license: 'http://www.crockford.com/JSON/license.html',
/*
    Stringify a JavaScript value, producing a JSON text.
*/
        stringify: function (v) {
            var f = s[typeof v];
            if (f) {
                v = f(v);
                if (typeof v === 'string') {
                    return v;
                }
            }
            return null;
        },
/*
    Parse a JSON text, producing a JavaScript value.
    If the text is not JSON parseable, then a SyntaxError is thrown.
*/
        'eval': function (text, reviver) {

            // The walk method is used to recursively walk the resulting structure so
            // that modifications can be made.

            function walk(holder, key) {
                var k, v, value = holder[key];
                if (value && typeof value === 'object') {
                    for (k in value) {
                        if (Object.hasOwnProperty.call(value, k)) {
                            v = walk(value, k);
                            if (v !== undefined) {
                                value[k] = v;
                            } else {
                                delete value[k];
                            }
                        }
                    }
                }
                return reviver.call(holder, key, value);
            }

            // Parsing happens in three stages. In the first stage, we replace certain
            // Unicode characters with escape sequences. JavaScript handles many characters
            // incorrectly, either silently deleting them, or treating them as line endings.

            if (cx.test(text)) {
                text = text.replace(cx, function (a) {
                    return '\\u' +
                            ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
                });
            }

            // In the second stage, we run the text against
            // regular expressions that look for non-JSON patterns. We are especially
            // concerned with '()' and 'new' because they can cause invocation, and '='
            // because it can cause mutation. But just to be safe, we want to reject all
            // unexpected forms.

            // We split the second stage into 4 regexp operations in order to work around
            // crippling inefficiencies in IE's and Safari's regexp engines. First we
            // replace all backslash pairs with '@' (a non-JSON character). Second, we
            // replace all simple value tokens with ']' characters. Third, we delete all
            // open brackets that follow a colon or comma or that begin the text. Finally,
            // we look to see that the remaining characters are only whitespace or ']' or
            // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.

            if (!/^[\],:{}\s]*$/.test(text.replace(/\\["\\\/bfnrtu]/g, '@').
                replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
                replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
                throw new SyntaxError("eval");
            }

            // In the third stage we use the eval function to compile the text into a
            // JavaScript structure. The '{' operator is subject to a syntactic ambiguity
            // in JavaScript: it can begin a block or an object literal. We wrap the text
            // in parens to eliminate the ambiguity.

            var result = eval('(' + text + ')');

            // In the optional fourth stage, we recursively walk the new structure, passing
            // each name/value pair to a reviver function for possible transformation.

            return typeof reviver === 'function' ?
                walk({'': result}, '') : result;
        },

        parse: function (text) {
            var at = 0,     // The index of the current character
                ch = ' ',   // The current character
                result,     // The final result
                value;      // The value function

            function error(m) {
                var e = new SyntaxError(m);
                e.at = at - 1;
                e.text = text;
                throw e;
            }

            function next() {
                ch = text.charAt(at);
                at += 1;
                return ch;
            }

            function white() {
                while (ch) {
                    if (ch <= ' ') {
                        next();
                    } else if (ch === '/') {
                        switch (next()) {
                            case '/':
                                while (next() && ch !== '\n' && ch !== '\r') { }
                                break;
                            case '*':
                                next();
                                for (;;) {
                                    if (ch) {
                                        if (ch === '*') {
                                            if (next() === '/') {
                                                next();
                                                break;
                                            }
                                        } else {
                                            next();
                                        }
                                    } else {
                                        error("Unterminated comment");
                                    }
                                }
                                break;
                            default:
                                error("Syntax error");
                        }
                    } else {
                        break;
                    }
                }
            }

            function string() {
                var i, s = '', t, u;

                if (ch === '"') {
    outer:          while (next()) {
                        if (ch === '"') {
                            next();
                            return s;
                        } else if (ch === '\\') {
                            switch (next()) {
                            case 'b':
                                s += '\b';
                                break;
                            case 'f':
                                s += '\f';
                                break;
                            case 'n':
                                s += '\n';
                                break;
                            case 'r':
                                s += '\r';
                                break;
                            case 't':
                                s += '\t';
                                break;
                            case 'u':
                                u = 0;
                                for (i = 0; i < 4; i += 1) {
                                    t = parseInt(next(), 16);
                                    if (!isFinite(t)) {
                                        break outer;
                                    }
                                    u = u * 16 + t;
                                }
                                s += String.fromCharCode(u);
                                break;
                            default:
                                s += ch;
                            }
                        } else {
                            s += ch;
                        }
                    }
                }
                error("Bad string");
            }

            function array() {
                var a = [];

                if (ch === '[') {
                    next();
                    white();
                    if (ch === ']') {
                        next();
                        return a;
                    }
                    while (ch) {
                        a.push(value());
                        white();
                        if (ch === ']') {
                            next();
                            return a;
                        } else if (ch !== ',') {
                            break;
                        }
                        next();
                        white();
                    }
                }
                error("Bad array");
            }

            function object() {
                var k, o = {};

                if (ch === '{') {
                    next();
                    white();
                    if (ch === '}') {
                        next();
                        return o;
                    }
                    while (ch) {
                        k = string();
                        white();
                        if (ch !== ':') {
                            break;
                        }
                        next();
                        o[k] = value();
                        white();
                        if (ch === '}') {
                            next();
                            return o;
                        } else if (ch !== ',') {
                            break;
                        }
                        next();
                        white();
                    }
                }
                error("Bad object");
            }

            function number() {
                var n = '', v;
                if (ch === '-') {
                    n = '-';
                    next();
                }
                while (ch >= '0' && ch <= '9') {
                    n += ch;
                    next();
                }
                if (ch === '.') {
                    n += '.';
                    while (next() && ch >= '0' && ch <= '9') {
                        n += ch;
                    }
                }
                if (ch === 'e' || ch === 'E') {
                    n += 'e';
                    next();
                    if (ch === '-' || ch === '+') {
                        n += ch;
                        next();
                    }
                    while (ch >= '0' && ch <= '9') {
                        n += ch;
                        next();
                    }
                }
                v = +n;
                if (!isFinite(v)) {
                    ////error("Bad number");
                } else {
                    return v;
                }
            }

            function word() {
                switch (ch) {
                    case 't':
                        if (next() === 'r' && next() === 'u' && next() === 'e') {
                            next();
                            return true;
                        }
                        break;
                    case 'f':
                        if (next() === 'a' && next() === 'l' && next() === 's' &&
                                next() === 'e') {
                            next();
                            return false;
                        }
                        break;
                    case 'n':
                        if (next() === 'u' && next() === 'l' && next() === 'l') {
                            next();
                            return null;
                        }
                        break;
                }
                error("Syntax error");
            }

            value = function() {
                white();
                switch (ch) {
                    case '{':
                        return object();
                    case '[':
                        return array();
                    case '"':
                        return string();
                    case '-':
                        return number();
                    default:
                        return ch >= '0' && ch <= '9' ? number() : word();
                }
            };

            result = value();
            white();
            if (ch) {
                error("Syntax error");
            }
            return result;
        }
    };
}();