/* 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