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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, decltype(std::declval<M>().begin()->first)>::value
- && std::is_constructible<Json, decltype(std::declval<M>().begin()->second)>::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, decltype(*std::declval<V>().begin())>::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
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