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-rw-r--r-- | ext/json11/json11.hpp | 232 |
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diff --git a/ext/json11/json11.hpp b/ext/json11/json11.hpp new file mode 100644 index 0000000..a68394b --- /dev/null +++ b/ext/json11/json11.hpp @@ -0,0 +1,232 @@ +/* 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 |