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+/* json11
+ *
+ * json11 is a tiny JSON library for C++11, providing JSON parsing and serialization.
+ *
+ * The core object provided by the library is json11::Json. A Json object represents any JSON
+ * value: null, bool, number (int or double), string (std::string), array (std::vector), or
+ * object (std::map).
+ *
+ * Json objects act like values: they can be assigned, copied, moved, compared for equality or
+ * order, etc. There are also helper methods Json::dump, to serialize a Json to a string, and
+ * Json::parse (static) to parse a std::string as a Json object.
+ *
+ * Internally, the various types of Json object are represented by the JsonValue class
+ * hierarchy.
+ *
+ * A note on numbers - JSON specifies the syntax of number formatting but not its semantics,
+ * so some JSON implementations distinguish between integers and floating-point numbers, while
+ * some don't. In json11, we choose the latter. Because some JSON implementations (namely
+ * JavaScript itself) treat all numbers as the same type, distinguishing the two leads
+ * to JSON that will be *silently* changed by a round-trip through those implementations.
+ * Dangerous! To avoid that risk, json11 stores all numbers as double internally, but also
+ * provides integer helpers.
+ *
+ * Fortunately, double-precision IEEE754 ('double') can precisely store any integer in the
+ * range +/-2^53, which includes every 'int' on most systems. (Timestamps often use int64
+ * or long long to avoid the Y2038K problem; a double storing microseconds since some epoch
+ * will be exact for +/- 275 years.)
+ */
+
+/* Copyright (c) 2013 Dropbox, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include <map>
+#include <memory>
+#include <initializer_list>
+
+#ifdef _MSC_VER
+ #if _MSC_VER <= 1800 // VS 2013
+ #ifndef noexcept
+ #define noexcept throw()
+ #endif
+
+ #ifndef snprintf
+ #define snprintf _snprintf_s
+ #endif
+ #endif
+#endif
+
+namespace json11 {
+
+enum JsonParse {
+ STANDARD, COMMENTS
+};
+
+class JsonValue;
+
+class Json final {
+public:
+ // Types
+ enum Type {
+ NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT
+ };
+
+ // Array and object typedefs
+ typedef std::vector<Json> array;
+ typedef std::map<std::string, Json> object;
+
+ // Constructors for the various types of JSON value.
+ Json() noexcept; // NUL
+ Json(std::nullptr_t) noexcept; // NUL
+ Json(double value); // NUMBER
+ Json(int value); // NUMBER
+ Json(bool value); // BOOL
+ Json(const std::string &value); // STRING
+ Json(std::string &&value); // STRING
+ Json(const char * value); // STRING
+ Json(const array &values); // ARRAY
+ Json(array &&values); // ARRAY
+ Json(const object &values); // OBJECT
+ Json(object &&values); // OBJECT
+
+ // Implicit constructor: anything with a to_json() function.
+ template <class T, class = decltype(&T::to_json)>
+ Json(const T & t) : Json(t.to_json()) {}
+
+ // Implicit constructor: map-like objects (std::map, std::unordered_map, etc)
+ template <class M, typename std::enable_if<
+ std::is_constructible<std::string, typename M::key_type>::value
+ && std::is_constructible<Json, typename M::mapped_type>::value,
+ int>::type = 0>
+ Json(const M & m) : Json(object(m.begin(), m.end())) {}
+
+ // Implicit constructor: vector-like objects (std::list, std::vector, std::set, etc)
+ template <class V, typename std::enable_if<
+ std::is_constructible<Json, typename V::value_type>::value,
+ int>::type = 0>
+ Json(const V & v) : Json(array(v.begin(), v.end())) {}
+
+ // This prevents Json(some_pointer) from accidentally producing a bool. Use
+ // Json(bool(some_pointer)) if that behavior is desired.
+ Json(void *) = delete;
+
+ // Accessors
+ Type type() const;
+
+ bool is_null() const { return type() == NUL; }
+ bool is_number() const { return type() == NUMBER; }
+ bool is_bool() const { return type() == BOOL; }
+ bool is_string() const { return type() == STRING; }
+ bool is_array() const { return type() == ARRAY; }
+ bool is_object() const { return type() == OBJECT; }
+
+ // Return the enclosed value if this is a number, 0 otherwise. Note that json11 does not
+ // distinguish between integer and non-integer numbers - number_value() and int_value()
+ // can both be applied to a NUMBER-typed object.
+ double number_value() const;
+ int int_value() const;
+
+ // Return the enclosed value if this is a boolean, false otherwise.
+ bool bool_value() const;
+ // Return the enclosed string if this is a string, "" otherwise.
+ const std::string &string_value() const;
+ // Return the enclosed std::vector if this is an array, or an empty vector otherwise.
+ const array &array_items() const;
+ // Return the enclosed std::map if this is an object, or an empty map otherwise.
+ const object &object_items() const;
+
+ // Return a reference to arr[i] if this is an array, Json() otherwise.
+ const Json & operator[](size_t i) const;
+ // Return a reference to obj[key] if this is an object, Json() otherwise.
+ const Json & operator[](const std::string &key) const;
+
+ // Serialize.
+ void dump(std::string &out) const;
+ std::string dump() const {
+ std::string out;
+ dump(out);
+ return out;
+ }
+
+ // Parse. If parse fails, return Json() and assign an error message to err.
+ static Json parse(const std::string & in,
+ std::string & err,
+ JsonParse strategy = JsonParse::STANDARD);
+ static Json parse(const char * in,
+ std::string & err,
+ JsonParse strategy = JsonParse::STANDARD) {
+ if (in) {
+ return parse(std::string(in), err, strategy);
+ } else {
+ err = "null input";
+ return nullptr;
+ }
+ }
+ // Parse multiple objects, concatenated or separated by whitespace
+ static std::vector<Json> parse_multi(
+ const std::string & in,
+ std::string::size_type & parser_stop_pos,
+ std::string & err,
+ JsonParse strategy = JsonParse::STANDARD);
+
+ static inline std::vector<Json> parse_multi(
+ const std::string & in,
+ std::string & err,
+ JsonParse strategy = JsonParse::STANDARD) {
+ std::string::size_type parser_stop_pos;
+ return parse_multi(in, parser_stop_pos, err, strategy);
+ }
+
+ bool operator== (const Json &rhs) const;
+ bool operator< (const Json &rhs) const;
+ bool operator!= (const Json &rhs) const { return !(*this == rhs); }
+ bool operator<= (const Json &rhs) const { return !(rhs < *this); }
+ bool operator> (const Json &rhs) const { return (rhs < *this); }
+ bool operator>= (const Json &rhs) const { return !(*this < rhs); }
+
+ /* has_shape(types, err)
+ *
+ * Return true if this is a JSON object and, for each item in types, has a field of
+ * the given type. If not, return false and set err to a descriptive message.
+ */
+ typedef std::initializer_list<std::pair<std::string, Type>> shape;
+ bool has_shape(const shape & types, std::string & err) const;
+
+private:
+ std::shared_ptr<JsonValue> m_ptr;
+};
+
+// Internal class hierarchy - JsonValue objects are not exposed to users of this API.
+class JsonValue {
+protected:
+ friend class Json;
+ friend class JsonInt;
+ friend class JsonDouble;
+ virtual Json::Type type() const = 0;
+ virtual bool equals(const JsonValue * other) const = 0;
+ virtual bool less(const JsonValue * other) const = 0;
+ virtual void dump(std::string &out) const = 0;
+ virtual double number_value() const;
+ virtual int int_value() const;
+ virtual bool bool_value() const;
+ virtual const std::string &string_value() const;
+ virtual const Json::array &array_items() const;
+ virtual const Json &operator[](size_t i) const;
+ virtual const Json::object &object_items() const;
+ virtual const Json &operator[](const std::string &key) const;
+ virtual ~JsonValue() {}
+};
+
+} // namespace json11