mirror of
https://github.com/nlohmann/json.git
synced 2024-12-02 21:19:01 +08:00
119 lines
4.2 KiB
C++
119 lines
4.2 KiB
C++
// __ _____ _____ _____
|
|
// __| | __| | | | JSON for Modern C++
|
|
// | | |__ | | | | | | version 3.11.3
|
|
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
|
|
//
|
|
// SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
#pragma once
|
|
|
|
#include <array> // array
|
|
#include <cstddef> // size_t
|
|
#include <cstdint> // uint8_t
|
|
#include <string> // string
|
|
|
|
#include <nlohmann/detail/macro_scope.hpp>
|
|
#if JSON_HAS_THREE_WAY_COMPARISON
|
|
#include <compare> // partial_ordering
|
|
#endif
|
|
|
|
NLOHMANN_JSON_NAMESPACE_BEGIN
|
|
namespace detail
|
|
{
|
|
|
|
///////////////////////////
|
|
// JSON type enumeration //
|
|
///////////////////////////
|
|
|
|
/*!
|
|
@brief the JSON type enumeration
|
|
|
|
This enumeration collects the different JSON types. It is internally used to
|
|
distinguish the stored values, and the functions @ref basic_json::is_null(),
|
|
@ref basic_json::is_object(), @ref basic_json::is_array(),
|
|
@ref basic_json::is_string(), @ref basic_json::is_boolean(),
|
|
@ref basic_json::is_number() (with @ref basic_json::is_number_integer(),
|
|
@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()),
|
|
@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and
|
|
@ref basic_json::is_structured() rely on it.
|
|
|
|
@note There are three enumeration entries (number_integer, number_unsigned, and
|
|
number_float), because the library distinguishes these three types for numbers:
|
|
@ref basic_json::number_unsigned_t is used for unsigned integers,
|
|
@ref basic_json::number_integer_t is used for signed integers, and
|
|
@ref basic_json::number_float_t is used for floating-point numbers or to
|
|
approximate integers which do not fit in the limits of their respective type.
|
|
|
|
@sa see @ref basic_json::basic_json(const value_t value_type) -- create a JSON
|
|
value with the default value for a given type
|
|
|
|
@since version 1.0.0
|
|
*/
|
|
enum class value_t : std::uint8_t
|
|
{
|
|
null, ///< null value
|
|
object, ///< object (unordered set of name/value pairs)
|
|
array, ///< array (ordered collection of values)
|
|
string, ///< string value
|
|
boolean, ///< boolean value
|
|
number_integer, ///< number value (signed integer)
|
|
number_unsigned, ///< number value (unsigned integer)
|
|
number_float, ///< number value (floating-point)
|
|
binary, ///< binary array (ordered collection of bytes)
|
|
discarded ///< discarded by the parser callback function
|
|
};
|
|
|
|
/*!
|
|
@brief comparison operator for JSON types
|
|
|
|
Returns an ordering that is similar to Python:
|
|
- order: null < boolean < number < object < array < string < binary
|
|
- furthermore, each type is not smaller than itself
|
|
- discarded values are not comparable
|
|
- binary is represented as a b"" string in python and directly comparable to a
|
|
string; however, making a binary array directly comparable with a string would
|
|
be surprising behavior in a JSON file.
|
|
|
|
@since version 1.0.0
|
|
*/
|
|
#if JSON_HAS_THREE_WAY_COMPARISON
|
|
inline std::partial_ordering operator<=>(const value_t lhs, const value_t rhs) noexcept // *NOPAD*
|
|
#else
|
|
inline bool operator<(const value_t lhs, const value_t rhs) noexcept
|
|
#endif
|
|
{
|
|
static constexpr std::array<std::uint8_t, 9> order = {{
|
|
0 /* null */, 3 /* object */, 4 /* array */, 5 /* string */,
|
|
1 /* boolean */, 2 /* integer */, 2 /* unsigned */, 2 /* float */,
|
|
6 /* binary */
|
|
}
|
|
};
|
|
|
|
const auto l_index = static_cast<std::size_t>(lhs);
|
|
const auto r_index = static_cast<std::size_t>(rhs);
|
|
#if JSON_HAS_THREE_WAY_COMPARISON
|
|
if (l_index < order.size() && r_index < order.size())
|
|
{
|
|
return order[l_index] <=> order[r_index]; // *NOPAD*
|
|
}
|
|
return std::partial_ordering::unordered;
|
|
#else
|
|
return l_index < order.size() && r_index < order.size() && order[l_index] < order[r_index];
|
|
#endif
|
|
}
|
|
|
|
// GCC selects the built-in operator< over an operator rewritten from
|
|
// a user-defined spaceship operator
|
|
// Clang, MSVC, and ICC select the rewritten candidate
|
|
// (see GCC bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105200)
|
|
#if JSON_HAS_THREE_WAY_COMPARISON && defined(__GNUC__)
|
|
inline bool operator<(const value_t lhs, const value_t rhs) noexcept
|
|
{
|
|
return std::is_lt(lhs <=> rhs); // *NOPAD*
|
|
}
|
|
#endif
|
|
|
|
} // namespace detail
|
|
NLOHMANN_JSON_NAMESPACE_END
|