michael@0: /*
michael@0:     http://www.JSON.org/json2.js
michael@0:     2008-05-25
michael@0: 
michael@0:     Public Domain.
michael@0: 
michael@0:     NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
michael@0: 
michael@0:     See http://www.JSON.org/js.html
michael@0: 
michael@0:     This file creates a global JSON object containing two methods: stringify
michael@0:     and parse.
michael@0: 
michael@0:         JSON.stringify(value, replacer, space)
michael@0:             value       any JavaScript value, usually an object or array.
michael@0: 
michael@0:             replacer    an optional parameter that determines how object
michael@0:                         values are stringified for objects without a toJSON
michael@0:                         method. It can be a function or an array.
michael@0: 
michael@0:             space       an optional parameter that specifies the indentation
michael@0:                         of nested structures. If it is omitted, the text will
michael@0:                         be packed without extra whitespace. If it is a number,
michael@0:                         it will specify the number of spaces to indent at each
michael@0:                         level. If it is a string (such as '\t' or ' '),
michael@0:                         it contains the characters used to indent at each level.
michael@0: 
michael@0:             This method produces a JSON text from a JavaScript value.
michael@0: 
michael@0:             When an object value is found, if the object contains a toJSON
michael@0:             method, its toJSON method will be called and the result will be
michael@0:             stringified. A toJSON method does not serialize: it returns the
michael@0:             value represented by the name/value pair that should be serialized,
michael@0:             or undefined if nothing should be serialized. The toJSON method
michael@0:             will be passed the key associated with the value, and this will be
michael@0:             bound to the object holding the key.
michael@0: 
michael@0:             For example, this would serialize Dates as ISO strings.
michael@0: 
michael@0:                 Date.prototype.toJSON = function (key) {
michael@0:                     function f(n) {
michael@0:                         // Format integers to have at least two digits.
michael@0:                         return n < 10 ? '0' + n : n;
michael@0:                     }
michael@0: 
michael@0:                     return this.getUTCFullYear()   + '-' +
michael@0:                          f(this.getUTCMonth() + 1) + '-' +
michael@0:                          f(this.getUTCDate())      + 'T' +
michael@0:                          f(this.getUTCHours())     + ':' +
michael@0:                          f(this.getUTCMinutes())   + ':' +
michael@0:                          f(this.getUTCSeconds())   + 'Z';
michael@0:                 };
michael@0: 
michael@0:             You can provide an optional replacer method. It will be passed the
michael@0:             key and value of each member, with this bound to the containing
michael@0:             object. The value that is returned from your method will be
michael@0:             serialized. If your method returns undefined, then the member will
michael@0:             be excluded from the serialization.
michael@0: 
michael@0:             If the replacer parameter is an array, then it will be used to
michael@0:             select the members to be serialized. It filters the results such
michael@0:             that only members with keys listed in the replacer array are
michael@0:             stringified.
michael@0: 
michael@0:             Values that do not have JSON representations, such as undefined or
michael@0:             functions, will not be serialized. Such values in objects will be
michael@0:             dropped; in arrays they will be replaced with null. You can use
michael@0:             a replacer function to replace those with JSON values.
michael@0:             JSON.stringify(undefined) returns undefined.
michael@0: 
michael@0:             The optional space parameter produces a stringification of the
michael@0:             value that is filled with line breaks and indentation to make it
michael@0:             easier to read.
michael@0: 
michael@0:             If the space parameter is a non-empty string, then that string will
michael@0:             be used for indentation. If the space parameter is a number, then
michael@0:             the indentation will be that many spaces.
michael@0: 
michael@0:             Example:
michael@0: 
michael@0:             text = JSON.stringify(['e', {pluribus: 'unum'}]);
michael@0:             // text is '["e",{"pluribus":"unum"}]'
michael@0: 
michael@0: 
michael@0:             text = JSON.stringify(['e', {pluribus: 'unum'}], null, '\t');
michael@0:             // text is '[\n\t"e",\n\t{\n\t\t"pluribus": "unum"\n\t}\n]'
michael@0: 
michael@0:             text = JSON.stringify([new Date()], function (key, value) {
michael@0:                 return this[key] instanceof Date ?
michael@0:                     'Date(' + this[key] + ')' : value;
michael@0:             });
michael@0:             // text is '["Date(---current time---)"]'
michael@0: 
michael@0: 
michael@0:         JSON.parse(text, reviver)
michael@0:             This method parses a JSON text to produce an object or array.
michael@0:             It can throw a SyntaxError exception.
michael@0: 
michael@0:             The optional reviver parameter is a function that can filter and
michael@0:             transform the results. It receives each of the keys and values,
michael@0:             and its return value is used instead of the original value.
michael@0:             If it returns what it received, then the structure is not modified.
michael@0:             If it returns undefined then the member is deleted.
michael@0: 
michael@0:             Example:
michael@0: 
michael@0:             // Parse the text. Values that look like ISO date strings will
michael@0:             // be converted to Date objects.
michael@0: 
michael@0:             myData = JSON.parse(text, function (key, value) {
michael@0:                 var a;
michael@0:                 if (typeof value === 'string') {
michael@0:                     a =
michael@0: /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);
michael@0:                     if (a) {
michael@0:                         return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],
michael@0:                             +a[5], +a[6]));
michael@0:                     }
michael@0:                 }
michael@0:                 return value;
michael@0:             });
michael@0: 
michael@0:             myData = JSON.parse('["Date(09/09/2001)"]', function (key, value) {
michael@0:                 var d;
michael@0:                 if (typeof value === 'string' &&
michael@0:                         value.slice(0, 5) === 'Date(' &&
michael@0:                         value.slice(-1) === ')') {
michael@0:                     d = new Date(value.slice(5, -1));
michael@0:                     if (d) {
michael@0:                         return d;
michael@0:                     }
michael@0:                 }
michael@0:                 return value;
michael@0:             });
michael@0: 
michael@0: 
michael@0:     This is a reference implementation. You are free to copy, modify, or
michael@0:     redistribute.
michael@0: 
michael@0:     This code should be minified before deployment.
michael@0:     See http://javascript.crockford.com/jsmin.html
michael@0: 
michael@0:     USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO
michael@0:     NOT CONTROL.
michael@0: */
michael@0: 
michael@0: /*jslint evil: true */
michael@0: 
michael@0: /*global JSON */
michael@0: 
michael@0: /*members "", "\b", "\t", "\n", "\f", "\r", "\"", JSON, "\\", call,
michael@0:     charCodeAt, getUTCDate, getUTCFullYear, getUTCHours, getUTCMinutes,
michael@0:     getUTCMonth, getUTCSeconds, hasOwnProperty, join, lastIndex, length,
michael@0:     parse, propertyIsEnumerable, prototype, push, replace, slice, stringify,
michael@0:     test, toJSON, toString
michael@0: */
michael@0: 
michael@0: var EXPORTED_SYMBOLS = ["JSON"];
michael@0: 
michael@0: // Create a JSON object only if one does not already exist. We create the
michael@0: // object in a closure to avoid creating global variables.
michael@0: 
michael@0:     JSON = function () {
michael@0: 
michael@0:         function f(n) {
michael@0:             // Format integers to have at least two digits.
michael@0:             return n < 10 ? '0' + n : n;
michael@0:         }
michael@0: 
michael@0:         Date.prototype.toJSON = function (key) {
michael@0: 
michael@0:             return this.getUTCFullYear()   + '-' +
michael@0:                  f(this.getUTCMonth() + 1) + '-' +
michael@0:                  f(this.getUTCDate())      + 'T' +
michael@0:                  f(this.getUTCHours())     + ':' +
michael@0:                  f(this.getUTCMinutes())   + ':' +
michael@0:                  f(this.getUTCSeconds())   + 'Z';
michael@0:         };
michael@0: 
michael@0:         var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
michael@0:             escapeable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
michael@0:             gap,
michael@0:             indent,
michael@0:             meta = {    // table of character substitutions
michael@0:                 '\b': '\\b',
michael@0:                 '\t': '\\t',
michael@0:                 '\n': '\\n',
michael@0:                 '\f': '\\f',
michael@0:                 '\r': '\\r',
michael@0:                 '"' : '\\"',
michael@0:                 '\\': '\\\\'
michael@0:             },
michael@0:             rep;
michael@0: 
michael@0: 
michael@0:         function quote(string) {
michael@0: 
michael@0: // If the string contains no control characters, no quote characters, and no
michael@0: // backslash characters, then we can safely slap some quotes around it.
michael@0: // Otherwise we must also replace the offending characters with safe escape
michael@0: // sequences.
michael@0: 
michael@0:             escapeable.lastIndex = 0;
michael@0:             return escapeable.test(string) ?
michael@0:                 '"' + string.replace(escapeable, function (a) {
michael@0:                     var c = meta[a];
michael@0:                     if (typeof c === 'string') {
michael@0:                         return c;
michael@0:                     }
michael@0:                     return '\\u' + ('0000' +
michael@0:                             (+(a.charCodeAt(0))).toString(16)).slice(-4);
michael@0:                 }) + '"' :
michael@0:                 '"' + string + '"';
michael@0:         }
michael@0: 
michael@0: 
michael@0:         function str(key, holder) {
michael@0: 
michael@0: // Produce a string from holder[key].
michael@0: 
michael@0:             var i,          // The loop counter.
michael@0:                 k,          // The member key.
michael@0:                 v,          // The member value.
michael@0:                 length,
michael@0:                 mind = gap,
michael@0:                 partial,
michael@0:                 value = holder[key];
michael@0: 
michael@0: // If the value has a toJSON method, call it to obtain a replacement value.
michael@0: 
michael@0:             if (value && typeof value === 'object' &&
michael@0:                     typeof value.toJSON === 'function') {
michael@0:                 value = value.toJSON(key);
michael@0:             }
michael@0: 
michael@0: // If we were called with a replacer function, then call the replacer to
michael@0: // obtain a replacement value.
michael@0: 
michael@0:             if (typeof rep === 'function') {
michael@0:                 value = rep.call(holder, key, value);
michael@0:             }
michael@0: 
michael@0: // What happens next depends on the value's type.
michael@0: 
michael@0:             switch (typeof value) {
michael@0:             case 'string':
michael@0:                 return quote(value);
michael@0: 
michael@0:             case 'number':
michael@0: 
michael@0: // JSON numbers must be finite. Encode non-finite numbers as null.
michael@0: 
michael@0:                 return isFinite(value) ? String(value) : 'null';
michael@0: 
michael@0:             case 'boolean':
michael@0:             case 'null':
michael@0: 
michael@0: // If the value is a boolean or null, convert it to a string. Note:
michael@0: // typeof null does not produce 'null'. The case is included here in
michael@0: // the remote chance that this gets fixed someday.
michael@0: 
michael@0:                 return String(value);
michael@0: 
michael@0: // If the type is 'object', we might be dealing with an object or an array or
michael@0: // null.
michael@0: 
michael@0:             case 'object':
michael@0: 
michael@0: // Due to a specification blunder in ECMAScript, typeof null is 'object',
michael@0: // so watch out for that case.
michael@0: 
michael@0:                 if (!value) {
michael@0:                     return 'null';
michael@0:                 }
michael@0: 
michael@0: // Make an array to hold the partial results of stringifying this object value.
michael@0: 
michael@0:                 gap += indent;
michael@0:                 partial = [];
michael@0: 
michael@0: // If the object has a dontEnum length property, we'll treat it as an array.
michael@0: 
michael@0:                 if (typeof value.length === 'number' &&
michael@0:                         !(value.propertyIsEnumerable('length'))) {
michael@0: 
michael@0: // The object is an array. Stringify every element. Use null as a placeholder
michael@0: // for non-JSON values.
michael@0: 
michael@0:                     length = value.length;
michael@0:                     for (i = 0; i < length; i += 1) {
michael@0:                         partial[i] = str(i, value) || 'null';
michael@0:                     }
michael@0: 
michael@0: // Join all of the elements together, separated with commas, and wrap them in
michael@0: // brackets.
michael@0: 
michael@0:                     v = partial.length === 0 ? '[]' :
michael@0:                         gap ? '[\n' + gap +
michael@0:                                 partial.join(',\n' + gap) + '\n' +
michael@0:                                     mind + ']' :
michael@0:                               '[' + partial.join(',') + ']';
michael@0:                     gap = mind;
michael@0:                     return v;
michael@0:                 }
michael@0: 
michael@0: // If the replacer is an array, use it to select the members to be stringified.
michael@0: 
michael@0:                 if (rep && typeof rep === 'object') {
michael@0:                     length = rep.length;
michael@0:                     for (i = 0; i < length; i += 1) {
michael@0:                         k = rep[i];
michael@0:                         if (typeof k === 'string') {
michael@0:                             v = str(k, value, rep);
michael@0:                             if (v) {
michael@0:                                 partial.push(quote(k) + (gap ? ': ' : ':') + v);
michael@0:                             }
michael@0:                         }
michael@0:                     }
michael@0:                 } else {
michael@0: 
michael@0: // Otherwise, iterate through all of the keys in the object.
michael@0: 
michael@0:                     for (k in value) {
michael@0:                         if (Object.hasOwnProperty.call(value, k)) {
michael@0:                             v = str(k, value, rep);
michael@0:                             if (v) {
michael@0:                                 partial.push(quote(k) + (gap ? ': ' : ':') + v);
michael@0:                             }
michael@0:                         }
michael@0:                     }
michael@0:                 }
michael@0: 
michael@0: // Join all of the member texts together, separated with commas,
michael@0: // and wrap them in braces.
michael@0: 
michael@0:                 v = partial.length === 0 ? '{}' :
michael@0:                     gap ? '{\n' + gap + partial.join(',\n' + gap) + '\n' +
michael@0:                             mind + '}' : '{' + partial.join(',') + '}';
michael@0:                 gap = mind;
michael@0:                 return v;
michael@0:             }
michael@0:         }
michael@0: 
michael@0: // Return the JSON object containing the stringify and parse methods.
michael@0: 
michael@0:         return {
michael@0:             stringify: function (value, replacer, space) {
michael@0: 
michael@0: // The stringify method takes a value and an optional replacer, and an optional
michael@0: // space parameter, and returns a JSON text. The replacer can be a function
michael@0: // that can replace values, or an array of strings that will select the keys.
michael@0: // A default replacer method can be provided. Use of the space parameter can
michael@0: // produce text that is more easily readable.
michael@0: 
michael@0:                 var i;
michael@0:                 gap = '';
michael@0:                 indent = '';
michael@0: 
michael@0: // If the space parameter is a number, make an indent string containing that
michael@0: // many spaces.
michael@0: 
michael@0:                 if (typeof space === 'number') {
michael@0:                     for (i = 0; i < space; i += 1) {
michael@0:                         indent += ' ';
michael@0:                     }
michael@0: 
michael@0: // If the space parameter is a string, it will be used as the indent string.
michael@0: 
michael@0:                 } else if (typeof space === 'string') {
michael@0:                     indent = space;
michael@0:                 }
michael@0: 
michael@0: // If there is a replacer, it must be a function or an array.
michael@0: // Otherwise, throw an error.
michael@0: 
michael@0:                 rep = replacer;
michael@0:                 if (replacer && typeof replacer !== 'function' &&
michael@0:                         (typeof replacer !== 'object' ||
michael@0:                          typeof replacer.length !== 'number')) {
michael@0:                     throw new Error('JSON.stringify');
michael@0:                 }
michael@0: 
michael@0: // Make a fake root object containing our value under the key of ''.
michael@0: // Return the result of stringifying the value.
michael@0: 
michael@0:                 return str('', {'': value});
michael@0:             },
michael@0: 
michael@0: 
michael@0:             parse: function (text, reviver) {
michael@0: 
michael@0: // The parse method takes a text and an optional reviver function, and returns
michael@0: // a JavaScript value if the text is a valid JSON text.
michael@0: 
michael@0:                 var j;
michael@0: 
michael@0:                 function walk(holder, key) {
michael@0: 
michael@0: // The walk method is used to recursively walk the resulting structure so
michael@0: // that modifications can be made.
michael@0: 
michael@0:                     var k, v, value = holder[key];
michael@0:                     if (value && typeof value === 'object') {
michael@0:                         for (k in value) {
michael@0:                             if (Object.hasOwnProperty.call(value, k)) {
michael@0:                                 v = walk(value, k);
michael@0:                                 if (v !== undefined) {
michael@0:                                     value[k] = v;
michael@0:                                 } else {
michael@0:                                     delete value[k];
michael@0:                                 }
michael@0:                             }
michael@0:                         }
michael@0:                     }
michael@0:                     return reviver.call(holder, key, value);
michael@0:                 }
michael@0: 
michael@0: 
michael@0: // Parsing happens in four stages. In the first stage, we replace certain
michael@0: // Unicode characters with escape sequences. JavaScript handles many characters
michael@0: // incorrectly, either silently deleting them, or treating them as line endings.
michael@0: 
michael@0:                 cx.lastIndex = 0;
michael@0:                 if (cx.test(text)) {
michael@0:                     text = text.replace(cx, function (a) {
michael@0:                         return '\\u' + ('0000' +
michael@0:                                 (+(a.charCodeAt(0))).toString(16)).slice(-4);
michael@0:                     });
michael@0:                 }
michael@0: 
michael@0: // In the second stage, we run the text against regular expressions that look
michael@0: // for non-JSON patterns. We are especially concerned with '()' and 'new'
michael@0: // because they can cause invocation, and '=' because it can cause mutation.
michael@0: // But just to be safe, we want to reject all unexpected forms.
michael@0: 
michael@0: // We split the second stage into 4 regexp operations in order to work around
michael@0: // crippling inefficiencies in IE's and Safari's regexp engines. First we
michael@0: // replace the JSON backslash pairs with '@' (a non-JSON character). Second, we
michael@0: // replace all simple value tokens with ']' characters. Third, we delete all
michael@0: // open brackets that follow a colon or comma or that begin the text. Finally,
michael@0: // we look to see that the remaining characters are only whitespace or ']' or
michael@0: // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.
michael@0: 
michael@0:                 if (/^[\],:{}\s]*$/.
michael@0: test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@').
michael@0: replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
michael@0: replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
michael@0: 
michael@0: // In the third stage we use the eval function to compile the text into a
michael@0: // JavaScript structure. The '{' operator is subject to a syntactic ambiguity
michael@0: // in JavaScript: it can begin a block or an object literal. We wrap the text
michael@0: // in parens to eliminate the ambiguity.
michael@0: 
michael@0:                     j = eval('(' + text + ')');
michael@0: 
michael@0: // In the optional fourth stage, we recursively walk the new structure, passing
michael@0: // each name/value pair to a reviver function for possible transformation.
michael@0: 
michael@0:                     return typeof reviver === 'function' ?
michael@0:                         walk({'': j}, '') : j;
michael@0:                 }
michael@0: 
michael@0: // If the text is not JSON parseable, then a SyntaxError is thrown.
michael@0: 
michael@0:                 throw new SyntaxError('JSON.parse');
michael@0:             }
michael@0:         };
michael@0:     }();
michael@0: