json3.js

/*! JSON v3.3.2 | https://bestiejs.github.io/json3 | Copyright 2012-2015, Kit Cambridge, Benjamin Tan | http://kit.mit-license.org */
;(function () {
  // Detect the `define` function exposed by asynchronous module loaders. The
  // strict `define` check is necessary for compatibility with `r.js`.
  var isLoader = typeof define === "function" && define.amd;

  // A set of types used to distinguish objects from primitives.
  var objectTypes = {
    "function": true,
    "object": true
  };

  // Detect the `exports` object exposed by CommonJS implementations.
  var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;

  // Use the `global` object exposed by Node (including Browserify via
  // `insert-module-globals`), Narwhal, and Ringo as the default context,
  // and the `window` object in browsers. Rhino exports a `global` function
  // instead.
  var root = objectTypes[typeof window] && window || this,
      freeGlobal = freeExports && objectTypes[typeof module] && module && !module.nodeType && typeof global == "object" && global;

  if (freeGlobal && (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal || freeGlobal.self === freeGlobal)) {
    root = freeGlobal;
  }

  // Public: Initializes JSON 3 using the given `context` object, attaching the
  // `stringify` and `parse` functions to the specified `exports` object.
  function runInContext(context, exports) {
    context || (context = root.Object());
    exports || (exports = root.Object());

    // Native constructor aliases.
    var Number = context.Number || root.Number,
        String = context.String || root.String,
        Object = context.Object || root.Object,
        Date = context.Date || root.Date,
        SyntaxError = context.SyntaxError || root.SyntaxError,
        TypeError = context.TypeError || root.TypeError,
        Math = context.Math || root.Math,
        nativeJSON = context.JSON || root.JSON;

    // Delegate to the native `stringify` and `parse` implementations.
    if (typeof nativeJSON == "object" && nativeJSON) {
      exports.stringify = nativeJSON.stringify;
      exports.parse = nativeJSON.parse;
    }

    // Convenience aliases.
    var objectProto = Object.prototype,
        getClass = objectProto.toString,
        isProperty = objectProto.hasOwnProperty,
        undefined;

    // Internal: Contains `try...catch` logic used by other functions.
    // This prevents other functions from being deoptimized.
    function attempt(func, errorFunc) {
      try {
        func();
      } catch (exception) {
        if (errorFunc) {
          errorFunc();
        }
      }
    }

    // Test the `Date#getUTC*` methods. Based on work by @Yaffle.
    var isExtended = new Date(-3509827334573292);
    attempt(function () {
      // The `getUTCFullYear`, `Month`, and `Date` methods return nonsensical
      // results for certain dates in Opera >= 10.53.
      isExtended = isExtended.getUTCFullYear() == -109252 && isExtended.getUTCMonth() === 0 && isExtended.getUTCDate() === 1 &&
        isExtended.getUTCHours() == 10 && isExtended.getUTCMinutes() == 37 && isExtended.getUTCSeconds() == 6 && isExtended.getUTCMilliseconds() == 708;
    });

    // Internal: Determines whether the native `JSON.stringify` and `parse`
    // implementations are spec-compliant. Based on work by Ken Snyder.
    function has(name) {
      if (has[name] != null) {
        // Return cached feature test result.
        return has[name];
      }
      var isSupported;
      if (name == "bug-string-char-index") {
        // IE <= 7 doesn't support accessing string characters using square
        // bracket notation. IE 8 only supports this for primitives.
        isSupported = "a"[0] != "a";
      } else if (name == "json") {
        // Indicates whether both `JSON.stringify` and `JSON.parse` are
        // supported.
        isSupported = has("json-stringify") && has("date-serialization") && has("json-parse");
      } else if (name == "date-serialization") {
        // Indicates whether `Date`s can be serialized accurately by `JSON.stringify`.
        isSupported = has("json-stringify") && isExtended;
        if (isSupported) {
          var stringify = exports.stringify;
          attempt(function () {
            isSupported =
              // JSON 2, Prototype <= 1.7, and older WebKit builds incorrectly
              // serialize extended years.
              stringify(new Date(-8.64e15)) == '"-271821-04-20T00:00:00.000Z"' &&
              // The milliseconds are optional in ES 5, but required in 5.1.
              stringify(new Date(8.64e15)) == '"+275760-09-13T00:00:00.000Z"' &&
              // Firefox <= 11.0 incorrectly serializes years prior to 0 as negative
              // four-digit years instead of six-digit years. Credits: @Yaffle.
              stringify(new Date(-621987552e5)) == '"-000001-01-01T00:00:00.000Z"' &&
              // Safari <= 5.1.5 and Opera >= 10.53 incorrectly serialize millisecond
              // values less than 1000. Credits: @Yaffle.
              stringify(new Date(-1)) == '"1969-12-31T23:59:59.999Z"';
          });
        }
      } else {
        var value, serialized = '{"a":[1,true,false,null,"\\u0000\\b\\n\\f\\r\\t"]}';
        // Test `JSON.stringify`.
        if (name == "json-stringify") {
          var stringify = exports.stringify, stringifySupported = typeof stringify == "function";
          if (stringifySupported) {
            // A test function object with a custom `toJSON` method.
            (value = function () {
              return 1;
            }).toJSON = value;
            attempt(function () {
              stringifySupported =
                // Firefox 3.1b1 and b2 serialize string, number, and boolean
                // primitives as object literals.
                stringify(0) === "0" &&
                // FF 3.1b1, b2, and JSON 2 serialize wrapped primitives as object
                // literals.
                stringify(new Number()) === "0" &&
                stringify(new String()) == '""' &&
                // FF 3.1b1, 2 throw an error if the value is `null`, `undefined`, or
                // does not define a canonical JSON representation (this applies to
                // objects with `toJSON` properties as well, *unless* they are nested
                // within an object or array).
                stringify(getClass) === undefined &&
                // IE 8 serializes `undefined` as `"undefined"`. Safari <= 5.1.7 and
                // FF 3.1b3 pass this test.
                stringify(undefined) === undefined &&
                // Safari <= 5.1.7 and FF 3.1b3 throw `Error`s and `TypeError`s,
                // respectively, if the value is omitted entirely.
                stringify() === undefined &&
                // FF 3.1b1, 2 throw an error if the given value is not a number,
                // string, array, object, Boolean, or `null` literal. This applies to
                // objects with custom `toJSON` methods as well, unless they are nested
                // inside object or array literals. YUI 3.0.0b1 ignores custom `toJSON`
                // methods entirely.
                stringify(value) === "1" &&
                stringify([value]) == "[1]" &&
                // Prototype <= 1.6.1 serializes `[undefined]` as `"[]"` instead of
                // `"[null]"`.
                stringify([undefined]) == "[null]" &&
                // YUI 3.0.0b1 fails to serialize `null` literals.
                stringify(null) == "null" &&
                // FF 3.1b1, 2 halts serialization if an array contains a function:
                // `[1, true, getClass, 1]` serializes as "[1,true,],". FF 3.1b3
                // elides non-JSON values from objects and arrays, unless they
                // define custom `toJSON` methods.
                stringify([undefined, getClass, null]) == "[null,null,null]" &&
                // Simple serialization test. FF 3.1b1 uses Unicode escape sequences
                // where character escape codes are expected (e.g., `\b` => `\u0008`).
                stringify({ "a": [value, true, false, null, "\x00\b\n\f\r\t"] }) == serialized &&
                // FF 3.1b1 and b2 ignore the `filter` and `width` arguments.
                stringify(null, value) === "1" &&
                stringify([1, 2], null, 1) == "[\n 1,\n 2\n]";
            }, function () {
              stringifySupported = false;
            });
          }
          isSupported = stringifySupported;
        }
        // Test `JSON.parse`.
        if (name == "json-parse") {
          var parse = exports.parse, parseSupported;
          if (typeof parse == "function") {
            attempt(function () {
              // FF 3.1b1, b2 will throw an exception if a bare literal is provided.
              // Conforming implementations should also coerce the initial argument to
              // a string prior to parsing.
              if (parse("0") === 0 && !parse(false)) {
                // Simple parsing test.
                value = parse(serialized);
                parseSupported = value["a"].length == 5 && value["a"][0] === 1;
                if (parseSupported) {
                  attempt(function () {
                    // Safari <= 5.1.2 and FF 3.1b1 allow unescaped tabs in strings.
                    parseSupported = !parse('"\t"');
                  });
                  if (parseSupported) {
                    attempt(function () {
                      // FF 4.0 and 4.0.1 allow leading `+` signs and leading
                      // decimal points. FF 4.0, 4.0.1, and IE 9-10 also allow
                      // certain octal literals.
                      parseSupported = parse("01") !== 1;
                    });
                  }
                  if (parseSupported) {
                    attempt(function () {
                      // FF 4.0, 4.0.1, and Rhino 1.7R3-R4 allow trailing decimal
                      // points. These environments, along with FF 3.1b1 and 2,
                      // also allow trailing commas in JSON objects and arrays.
                      parseSupported = parse("1.") !== 1;
                    });
                  }
                }
              }
            }, function () {
              parseSupported = false;
            });
          }
          isSupported = parseSupported;
        }
      }
      return has[name] = !!isSupported;
    }
    has["bug-string-char-index"] = has["date-serialization"] = has["json"] = has["json-stringify"] = has["json-parse"] = null;

    if (!has("json")) {
      // Common `[[Class]]` name aliases.
      var functionClass = "[object Function]",
          dateClass = "[object Date]",
          numberClass = "[object Number]",
          stringClass = "[object String]",
          arrayClass = "[object Array]",
          booleanClass = "[object Boolean]";

      // Detect incomplete support for accessing string characters by index.
      var charIndexBuggy = has("bug-string-char-index");

      // Internal: Normalizes the `for...in` iteration algorithm across
      // environments. Each enumerated key is yielded to a `callback` function.
      var forOwn = function (object, callback) {
        var size = 0, Properties, dontEnums, property;

        // Tests for bugs in the current environment's `for...in` algorithm. The
        // `valueOf` property inherits the non-enumerable flag from
        // `Object.prototype` in older versions of IE, Netscape, and Mozilla.
        (Properties = function () {
          this.valueOf = 0;
        }).prototype.valueOf = 0;

        // Iterate over a new instance of the `Properties` class.
        dontEnums = new Properties();
        for (property in dontEnums) {
          // Ignore all properties inherited from `Object.prototype`.
          if (isProperty.call(dontEnums, property)) {
            size++;
          }
        }
        Properties = dontEnums = null;

        // Normalize the iteration algorithm.
        if (!size) {
          // A list of non-enumerable properties inherited from `Object.prototype`.
          dontEnums = ["valueOf", "toString", "toLocaleString", "propertyIsEnumerable", "isPrototypeOf", "hasOwnProperty", "constructor"];
          // IE <= 8, Mozilla 1.0, and Netscape 6.2 ignore shadowed non-enumerable
          // properties.
          forOwn = function (object, callback) {
            var isFunction = getClass.call(object) == functionClass, property, length;
            var hasProperty = !isFunction && typeof object.constructor != "function" && objectTypes[typeof object.hasOwnProperty] && object.hasOwnProperty || isProperty;
            for (property in object) {
              // Gecko <= 1.0 enumerates the `prototype` property of functions under
              // certain conditions; IE does not.
              if (!(isFunction && property == "prototype") && hasProperty.call(object, property)) {
                callback(property);
              }
            }
            // Manually invoke the callback for each non-enumerable property.
            for (length = dontEnums.length; property = dontEnums[--length];) {
              if (hasProperty.call(object, property)) {
                callback(property);
              }
            }
          };
        } else {
          // No bugs detected; use the standard `for...in` algorithm.
          forOwn = function (object, callback) {
            var isFunction = getClass.call(object) == functionClass, property, isConstructor;
            for (property in object) {
              if (!(isFunction && property == "prototype") && isProperty.call(object, property) && !(isConstructor = property === "constructor")) {
                callback(property);
              }
            }
            // Manually invoke the callback for the `constructor` property due to
            // cross-environment inconsistencies.
            if (isConstructor || isProperty.call(object, (property = "constructor"))) {
              callback(property);
            }
          };
        }
        return forOwn(object, callback);
      };

      // Public: Serializes a JavaScript `value` as a JSON string. The optional
      // `filter` argument may specify either a function that alters how object and
      // array members are serialized, or an array of strings and numbers that
      // indicates which properties should be serialized. The optional `width`
      // argument may be either a string or number that specifies the indentation
      // level of the output.
      if (!has("json-stringify") && !has("date-serialization")) {
        // Internal: A map of control characters and their escaped equivalents.
        var Escapes = {
          92: "\\\\",
          34: '\\"',
          8: "\\b",
          12: "\\f",
          10: "\\n",
          13: "\\r",
          9: "\\t"
        };

        // Internal: Converts `value` into a zero-padded string such that its
        // length is at least equal to `width`. The `width` must be <= 6.
        var leadingZeroes = "000000";
        var toPaddedString = function (width, value) {
          // The `|| 0` expression is necessary to work around a bug in
          // Opera <= 7.54u2 where `0 == -0`, but `String(-0) !== "0"`.
          return (leadingZeroes + (value || 0)).slice(-width);
        };

        // Internal: Serializes a date object.
        var serializeDate = function (value) {
          var getData, year, month, date, time, hours, minutes, seconds, milliseconds;
          // Define additional utility methods if the `Date` methods are buggy.
          if (!isExtended) {
            var floor = Math.floor;
            // A mapping between the months of the year and the number of days between
            // January 1st and the first of the respective month.
            var Months = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334];
            // Internal: Calculates the number of days between the Unix epoch and the
            // first day of the given month.
            var getDay = function (year, month) {
              return Months[month] + 365 * (year - 1970) + floor((year - 1969 + (month = +(month > 1))) / 4) - floor((year - 1901 + month) / 100) + floor((year - 1601 + month) / 400);
            };
            getData = function (value) {
              // Manually compute the year, month, date, hours, minutes,
              // seconds, and milliseconds if the `getUTC*` methods are
              // buggy. Adapted from @Yaffle's `date-shim` project.
              date = floor(value / 864e5);
              for (year = floor(date / 365.2425) + 1970 - 1; getDay(year + 1, 0) <= date; year++);
              for (month = floor((date - getDay(year, 0)) / 30.42); getDay(year, month + 1) <= date; month++);
              date = 1 + date - getDay(year, month);
              // The `time` value specifies the time within the day (see ES
              // 5.1 section 15.9.1.2). The formula `(A % B + B) % B` is used
              // to compute `A modulo B`, as the `%` operator does not
              // correspond to the `modulo` operation for negative numbers.
              time = (value % 864e5 + 864e5) % 864e5;
              // The hours, minutes, seconds, and milliseconds are obtained by
              // decomposing the time within the day. See section 15.9.1.10.
              hours = floor(time / 36e5) % 24;
              minutes = floor(time / 6e4) % 60;
              seconds = floor(time / 1e3) % 60;
              milliseconds = time % 1e3;
            };
          } else {
            getData = function (value) {
              year = value.getUTCFullYear();
              month = value.getUTCMonth();
              date = value.getUTCDate();
              hours = value.getUTCHours();
              minutes = value.getUTCMinutes();
              seconds = value.getUTCSeconds();
              milliseconds = value.getUTCMilliseconds();
            };
          }
          serializeDate = function (value) {
            if (value > -1 / 0 && value < 1 / 0) {
              // Dates are serialized according to the `Date#toJSON` method
              // specified in ES 5.1 section 15.9.5.44. See section 15.9.1.15
              // for the ISO 8601 date time string format.
              getData(value);
              // Serialize extended years correctly.
              value = (year <= 0 || year >= 1e4 ? (year < 0 ? "-" : "+") + toPaddedString(6, year < 0 ? -year : year) : toPaddedString(4, year)) +
              "-" + toPaddedString(2, month + 1) + "-" + toPaddedString(2, date) +
              // Months, dates, hours, minutes, and seconds should have two
              // digits; milliseconds should have three.
              "T" + toPaddedString(2, hours) + ":" + toPaddedString(2, minutes) + ":" + toPaddedString(2, seconds) +
              // Milliseconds are optional in ES 5.0, but required in 5.1.
              "." + toPaddedString(3, milliseconds) + "Z";
              year = month = date = hours = minutes = seconds = milliseconds = null;
            } else {
              value = null;
            }
            return value;
          };
          return serializeDate(value);
        };

        // For environments with `JSON.stringify` but buggy date serialization,
        // we override the native `Date#toJSON` implementation with a
        // spec-compliant one.
        if (has("json-stringify") && !has("date-serialization")) {
          // Internal: the `Date#toJSON` implementation used to override the native one.
          function dateToJSON (key) {
            return serializeDate(this);
          }

          // Public: `JSON.stringify`. See ES 5.1 section 15.12.3.
          var nativeStringify = exports.stringify;
          exports.stringify = function (source, filter, width) {
            var nativeToJSON = Date.prototype.toJSON;
            Date.prototype.toJSON = dateToJSON;
            var result = nativeStringify(source, filter, width);
            Date.prototype.toJSON = nativeToJSON;
            return result;
          }
        } else {
          // Internal: Double-quotes a string `value`, replacing all ASCII control
          // characters (characters with code unit values between 0 and 31) with
          // their escaped equivalents. This is an implementation of the
          // `Quote(value)` operation defined in ES 5.1 section 15.12.3.
          var unicodePrefix = "\\u00";
          var escapeChar = function (character) {
            var charCode = character.charCodeAt(0), escaped = Escapes[charCode];
            if (escaped) {
              return escaped;
            }
            return unicodePrefix + toPaddedString(2, charCode.toString(16));
          };
          var reEscape = /[\x00-\x1f\x22\x5c]/g;
          var quote = function (value) {
            reEscape.lastIndex = 0;
            return '"' +
              (
                reEscape.test(value)
                  ? value.replace(reEscape, escapeChar)
                  : value
              ) +
              '"';
          };

          // Internal: Recursively serializes an object. Implements the
          // `Str(key, holder)`, `JO(value)`, and `JA(value)` operations.
          var serialize = function (property, object, callback, properties, whitespace, indentation, stack) {
            var value, type, className, results, element, index, length, prefix, result;
            attempt(function () {
              // Necessary for host object support.
              value = object[property];
            });
            if (typeof value == "object" && value) {
              if (value.getUTCFullYear && getClass.call(value) == dateClass && value.toJSON === Date.prototype.toJSON) {
                value = serializeDate(value);
              } else if (typeof value.toJSON == "function") {
                value = value.toJSON(property);
              }
            }
            if (callback) {
              // If a replacement function was provided, call it to obtain the value
              // for serialization.
              value = callback.call(object, property, value);
            }
            // Exit early if value is `undefined` or `null`.
            if (value == undefined) {
              return value === undefined ? value : "null";
            }
            type = typeof value;
            // Only call `getClass` if the value is an object.
            if (type == "object") {
              className = getClass.call(value);
            }
            switch (className || type) {
              case "boolean":
              case booleanClass:
                // Booleans are represented literally.
                return "" + value;
              case "number":
              case numberClass:
                // JSON numbers must be finite. `Infinity` and `NaN` are serialized as
                // `"null"`.
                return value > -1 / 0 && value < 1 / 0 ? "" + value : "null";
              case "string":
              case stringClass:
                // Strings are double-quoted and escaped.
                return quote("" + value);
            }
            // Recursively serialize objects and arrays.
            if (typeof value == "object") {
              // Check for cyclic structures. This is a linear search; performance
              // is inversely proportional to the number of unique nested objects.
              for (length = stack.length; length--;) {
                if (stack[length] === value) {
                  // Cyclic structures cannot be serialized by `JSON.stringify`.
                  throw TypeError();
                }
              }
              // Add the object to the stack of traversed objects.
              stack.push(value);
              results = [];
              // Save the current indentation level and indent one additional level.
              prefix = indentation;
              indentation += whitespace;
              if (className == arrayClass) {
                // Recursively serialize array elements.
                for (index = 0, length = value.length; index < length; index++) {
                  element = serialize(index, value, callback, properties, whitespace, indentation, stack);
                  results.push(element === undefined ? "null" : element);
                }
                result = results.length ? (whitespace ? "[\n" + indentation + results.join(",\n" + indentation) + "\n" + prefix + "]" : ("[" + results.join(",") + "]")) : "[]";
              } else {
                // Recursively serialize object members. Members are selected from
                // either a user-specified list of property names, or the object
                // itself.
                forOwn(properties || value, function (property) {
                  var element = serialize(property, value, callback, properties, whitespace, indentation, stack);
                  if (element !== undefined) {
                    // According to ES 5.1 section 15.12.3: "If `gap` {whitespace}
                    // is not the empty string, let `member` {quote(property) + ":"}
                    // be the concatenation of `member` and the `space` character."
                    // The "`space` character" refers to the literal space
                    // character, not the `space` {width} argument provided to
                    // `JSON.stringify`.
                    results.push(quote(property) + ":" + (whitespace ? " " : "") + element);
                  }
                });
                result = results.length ? (whitespace ? "{\n" + indentation + results.join(",\n" + indentation) + "\n" + prefix + "}" : ("{" + results.join(",") + "}")) : "{}";
              }
              // Remove the object from the traversed object stack.
              stack.pop();
              return result;
            }
          };

          // Public: `JSON.stringify`. See ES 5.1 section 15.12.3.
          exports.stringify = function (source, filter, width) {
            var whitespace, callback, properties, className;
            if (objectTypes[typeof filter] && filter) {
              className = getClass.call(filter);
              if (className == functionClass) {
                callback = filter;
              } else if (className == arrayClass) {
                // Convert the property names array into a makeshift set.
                properties = {};
                for (var index = 0, length = filter.length, value; index < length;) {
                  value = filter[index++];
                  className = getClass.call(value);
                  if (className == "[object String]" || className == "[object Number]") {
                    properties[value] = 1;
                  }
                }
              }
            }
            if (width) {
              className = getClass.call(width);
              if (className == numberClass) {
                // Convert the `width` to an integer and create a string containing
                // `width` number of space characters.
                if ((width -= width % 1) > 0) {
                  if (width > 10) {
                    width = 10;
                  }
                  for (whitespace = ""; whitespace.length < width;) {
                    whitespace += " ";
                  }
                }
              } else if (className == stringClass) {
                whitespace = width.length <= 10 ? width : width.slice(0, 10);
              }
            }
            // Opera <= 7.54u2 discards the values associated with empty string keys
            // (`""`) only if they are used directly within an object member list
            // (e.g., `!("" in { "": 1})`).
            return serialize("", (value = {}, value[""] = source, value), callback, properties, whitespace, "", []);
          };
        }
      }

      // Public: Parses a JSON source string.
      if (!has("json-parse")) {
        var fromCharCode = String.fromCharCode;

        // Internal: A map of escaped control characters and their unescaped
        // equivalents.
        var Unescapes = {
          92: "\\",
          34: '"',
          47: "/",
          98: "\b",
          116: "\t",
          110: "\n",
          102: "\f",
          114: "\r"
        };

        // Internal: Stores the parser state.
        var Index, Source;

        // Internal: Resets the parser state and throws a `SyntaxError`.
        var abort = function () {
          Index = Source = null;
          throw SyntaxError();
        };

        // Internal: Returns the next token, or `"$"` if the parser has reached
        // the end of the source string. A token may be a string, number, `null`
        // literal, or Boolean literal.
        var lex = function () {
          var source = Source, length = source.length, value, begin, position, isSigned, charCode;
          while (Index < length) {
            charCode = source.charCodeAt(Index);
            switch (charCode) {
              case 9: case 10: case 13: case 32:
                // Skip whitespace tokens, including tabs, carriage returns, line
                // feeds, and space characters.
                Index++;
                break;
              case 123: case 125: case 91: case 93: case 58: case 44:
                // Parse a punctuator token (`{`, `}`, `[`, `]`, `:`, or `,`) at
                // the current position.
                value = charIndexBuggy ? source.charAt(Index) : source[Index];
                Index++;
                return value;
              case 34:
                // `"` delimits a JSON string; advance to the next character and
                // begin parsing the string. String tokens are prefixed with the
                // sentinel `@` character to distinguish them from punctuators and
                // end-of-string tokens.
                for (value = "@", Index++; Index < length;) {
                  charCode = source.charCodeAt(Index);
                  if (charCode < 32) {
                    // Unescaped ASCII control characters (those with a code unit
                    // less than the space character) are not permitted.
                    abort();
                  } else if (charCode == 92) {
                    // A reverse solidus (`\`) marks the beginning of an escaped
                    // control character (including `"`, `\`, and `/`) or Unicode
                    // escape sequence.
                    charCode = source.charCodeAt(++Index);
                    switch (charCode) {
                      case 92: case 34: case 47: case 98: case 116: case 110: case 102: case 114:
                        // Revive escaped control characters.
                        value += Unescapes[charCode];
                        Index++;
                        break;
                      case 117:
                        // `\u` marks the beginning of a Unicode escape sequence.
                        // Advance to the first character and validate the
                        // four-digit code point.
                        begin = ++Index;
                        for (position = Index + 4; Index < position; Index++) {
                          charCode = source.charCodeAt(Index);
                          // A valid sequence comprises four hexdigits (case-
                          // insensitive) that form a single hexadecimal value.
                          if (!(charCode >= 48 && charCode <= 57 || charCode >= 97 && charCode <= 102 || charCode >= 65 && charCode <= 70)) {
                            // Invalid Unicode escape sequence.
                            abort();
                          }
                        }
                        // Revive the escaped character.
                        value += fromCharCode("0x" + source.slice(begin, Index));
                        break;
                      default:
                        // Invalid escape sequence.
                        abort();
                    }
                  } else {
                    if (charCode == 34) {
                      // An unescaped double-quote character marks the end of the
                      // string.
                      break;
                    }
                    charCode = source.charCodeAt(Index);
                    begin = Index;
                    // Optimize for the common case where a string is valid.
                    while (charCode >= 32 && charCode != 92 && charCode != 34) {
                      charCode = source.charCodeAt(++Index);
                    }
                    // Append the string as-is.
                    value += source.slice(begin, Index);
                  }
                }
                if (source.charCodeAt(Index) == 34) {
                  // Advance to the next character and return the revived string.
                  Index++;
                  return value;
                }
                // Unterminated string.
                abort();
              default:
                // Parse numbers and literals.
                begin = Index;
                // Advance past the negative sign, if one is specified.
                if (charCode == 45) {
                  isSigned = true;
                  charCode = source.charCodeAt(++Index);
                }
                // Parse an integer or floating-point value.
                if (charCode >= 48 && charCode <= 57) {
                  // Leading zeroes are interpreted as octal literals.
                  if (charCode == 48 && ((charCode = source.charCodeAt(Index + 1)), charCode >= 48 && charCode <= 57)) {
                    // Illegal octal literal.
                    abort();
                  }
                  isSigned = false;
                  // Parse the integer component.
                  for (; Index < length && ((charCode = source.charCodeAt(Index)), charCode >= 48 && charCode <= 57); Index++);
                  // Floats cannot contain a leading decimal point; however, this
                  // case is already accounted for by the parser.
                  if (source.charCodeAt(Index) == 46) {
                    position = ++Index;
                    // Parse the decimal component.
                    for (; position < length; position++) {
                      charCode = source.charCodeAt(position);
                      if (charCode < 48 || charCode > 57) {
                        break;
                      }
                    }
                    if (position == Index) {
                      // Illegal trailing decimal.
                      abort();
                    }
                    Index = position;
                  }
                  // Parse exponents. The `e` denoting the exponent is
                  // case-insensitive.
                  charCode = source.charCodeAt(Index);
                  if (charCode == 101 || charCode == 69) {
                    charCode = source.charCodeAt(++Index);
                    // Skip past the sign following the exponent, if one is
                    // specified.
                    if (charCode == 43 || charCode == 45) {
                      Index++;
                    }
                    // Parse the exponential component.
                    for (position = Index; position < length; position++) {
                      charCode = source.charCodeAt(position);
                      if (charCode < 48 || charCode > 57) {
                        break;
                      }
                    }
                    if (position == Index) {
                      // Illegal empty exponent.
                      abort();
                    }
                    Index = position;
                  }
                  // Coerce the parsed value to a JavaScript number.
                  return +source.slice(begin, Index);
                }
                // A negative sign may only precede numbers.
                if (isSigned) {
                  abort();
                }
                // `true`, `false`, and `null` literals.
                var temp = source.slice(Index, Index + 4);
                if (temp == "true") {
                  Index += 4;
                  return true;
                } else if (temp == "fals" && source.charCodeAt(Index + 4 ) == 101) {
                  Index += 5;
                  return false;
                } else if (temp == "null") {
                  Index += 4;
                  return null;
                }
                // Unrecognized token.
                abort();
            }
          }
          // Return the sentinel `$` character if the parser has reached the end
          // of the source string.
          return "$";
        };

        // Internal: Parses a JSON `value` token.
        var get = function (value) {
          var results, hasMembers;
          if (value == "$") {
            // Unexpected end of input.
            abort();
          }
          if (typeof value == "string") {
            if ((charIndexBuggy ? value.charAt(0) : value[0]) == "@") {
              // Remove the sentinel `@` character.
              return value.slice(1);
            }
            // Parse object and array literals.
            if (value == "[") {
              // Parses a JSON array, returning a new JavaScript array.
              results = [];
              for (;;) {
                value = lex();
                // A closing square bracket marks the end of the array literal.
                if (value == "]") {
                  break;
                }
                // If the array literal contains elements, the current token
                // should be a comma separating the previous element from the
                // next.
                if (hasMembers) {
                  if (value == ",") {
                    value = lex();
                    if (value == "]") {
                      // Unexpected trailing `,` in array literal.
                      abort();
                    }
                  } else {
                    // A `,` must separate each array element.
                    abort();
                  }
                } else {
                  hasMembers = true;
                }
                // Elisions and leading commas are not permitted.
                if (value == ",") {
                  abort();
                }
                results.push(get(value));
              }
              return results;
            } else if (value == "{") {
              // Parses a JSON object, returning a new JavaScript object.
              results = {};
              for (;;) {
                value = lex();
                // A closing curly brace marks the end of the object literal.
                if (value == "}") {
                  break;
                }
                // If the object literal contains members, the current token
                // should be a comma separator.
                if (hasMembers) {
                  if (value == ",") {
                    value = lex();
                    if (value == "}") {
                      // Unexpected trailing `,` in object literal.
                      abort();
                    }
                  } else {
                    // A `,` must separate each object member.
                    abort();
                  }
                } else {
                  hasMembers = true;
                }
                // Leading commas are not permitted, object property names must be
                // double-quoted strings, and a `:` must separate each property
                // name and value.
                if (value == "," || typeof value != "string" || (charIndexBuggy ? value.charAt(0) : value[0]) != "@" || lex() != ":") {
                  abort();
                }
                results[value.slice(1)] = get(lex());
              }
              return results;
            }
            // Unexpected token encountered.
            abort();
          }
          return value;
        };

        // Internal: Updates a traversed object member.
        var update = function (source, property, callback) {
          var element = walk(source, property, callback);
          if (element === undefined) {
            delete source[property];
          } else {
            source[property] = element;
          }
        };

        // Internal: Recursively traverses a parsed JSON object, invoking the
        // `callback` function for each value. This is an implementation of the
        // `Walk(holder, name)` operation defined in ES 5.1 section 15.12.2.
        var walk = function (source, property, callback) {
          var value = source[property], length;
          if (typeof value == "object" && value) {
            // `forOwn` can't be used to traverse an array in Opera <= 8.54
            // because its `Object#hasOwnProperty` implementation returns `false`
            // for array indices (e.g., `![1, 2, 3].hasOwnProperty("0")`).
            if (getClass.call(value) == arrayClass) {
              for (length = value.length; length--;) {
                update(getClass, forOwn, value, length, callback);
              }
            } else {
              forOwn(value, function (property) {
                update(value, property, callback);
              });
            }
          }
          return callback.call(source, property, value);
        };

        // Public: `JSON.parse`. See ES 5.1 section 15.12.2.
        exports.parse = function (source, callback) {
          var result, value;
          Index = 0;
          Source = "" + source;
          result = get(lex());
          // If a JSON string contains multiple tokens, it is invalid.
          if (lex() != "$") {
            abort();
          }
          // Reset the parser state.
          Index = Source = null;
          return callback && getClass.call(callback) == functionClass ? walk((value = {}, value[""] = result, value), "", callback) : result;
        };
      }
    }

    exports.runInContext = runInContext;
    return exports;
  }

  if (freeExports && !isLoader) {
    // Export for CommonJS environments.
    runInContext(root, freeExports);
  } else {
    // Export for web browsers and JavaScript engines.
    var nativeJSON = root.JSON,
        previousJSON = root.JSON3,
        isRestored = false;

    var JSON3 = runInContext(root, (root.JSON3 = {
      // Public: Restores the original value of the global `JSON` object and
      // returns a reference to the `JSON3` object.
      "noConflict": function () {
        if (!isRestored) {
          isRestored = true;
          root.JSON = nativeJSON;
          root.JSON3 = previousJSON;
          nativeJSON = previousJSON = null;
        }
        return JSON3;
      }
    }));

    root.JSON = {
      "parse": JSON3.parse,
      "stringify": JSON3.stringify
    };
  }

  // Export for asynchronous module loaders.
  if (isLoader) {
    define(function () {
      return JSON3;
    });
  }
}).call(this);