json/include/nlohmann/detail/macro_scope.hpp
Watal M. Iwasaki 5ccdaf643f Remove C++17 extension warning from clang; #1535
- Switch off `nodiscard` for clang unless C++17 is detected.
- Detect C++ standard before the switch.
2019-03-28 14:38:58 +09:00

156 lines
6.9 KiB
C++

#pragma once
#include <utility> // pair
// This file contains all internal macro definitions
// You MUST include macro_unscope.hpp at the end of json.hpp to undef all of them
// exclude unsupported compilers
#if !defined(JSON_SKIP_UNSUPPORTED_COMPILER_CHECK)
#if defined(__clang__)
#if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
#error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
#endif
#elif defined(__GNUC__) && !(defined(__ICC) || defined(__INTEL_COMPILER))
#if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40800
#error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
#endif
#endif
#endif
// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
#define JSON_HAS_CPP_14
#endif
// disable float-equal warnings on GCC/clang
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wfloat-equal"
#endif
// disable documentation warnings on clang
#if defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdocumentation"
#endif
// allow for portable deprecation warnings
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#define JSON_DEPRECATED __attribute__((deprecated))
#elif defined(_MSC_VER)
#define JSON_DEPRECATED __declspec(deprecated)
#else
#define JSON_DEPRECATED
#endif
// allow for portable nodiscard warnings
#if defined(__has_cpp_attribute)
#if __has_cpp_attribute(nodiscard)
#if defined(__clang__) && !defined(JSON_HAS_CPP_17) // issue #1535
#define JSON_NODISCARD
#else
#define JSON_NODISCARD [[nodiscard]]
#endif
#elif __has_cpp_attribute(gnu::warn_unused_result)
#define JSON_NODISCARD [[gnu::warn_unused_result]]
#else
#define JSON_NODISCARD
#endif
#else
#define JSON_NODISCARD
#endif
// allow to disable exceptions
#if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND)) && !defined(JSON_NOEXCEPTION)
#define JSON_THROW(exception) throw exception
#define JSON_TRY try
#define JSON_CATCH(exception) catch(exception)
#define JSON_INTERNAL_CATCH(exception) catch(exception)
#else
#include <cstdlib>
#define JSON_THROW(exception) std::abort()
#define JSON_TRY if(true)
#define JSON_CATCH(exception) if(false)
#define JSON_INTERNAL_CATCH(exception) if(false)
#endif
// override exception macros
#if defined(JSON_THROW_USER)
#undef JSON_THROW
#define JSON_THROW JSON_THROW_USER
#endif
#if defined(JSON_TRY_USER)
#undef JSON_TRY
#define JSON_TRY JSON_TRY_USER
#endif
#if defined(JSON_CATCH_USER)
#undef JSON_CATCH
#define JSON_CATCH JSON_CATCH_USER
#undef JSON_INTERNAL_CATCH
#define JSON_INTERNAL_CATCH JSON_CATCH_USER
#endif
#if defined(JSON_INTERNAL_CATCH_USER)
#undef JSON_INTERNAL_CATCH
#define JSON_INTERNAL_CATCH JSON_INTERNAL_CATCH_USER
#endif
// manual branch prediction
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#define JSON_LIKELY(x) __builtin_expect(x, 1)
#define JSON_UNLIKELY(x) __builtin_expect(x, 0)
#else
#define JSON_LIKELY(x) x
#define JSON_UNLIKELY(x) x
#endif
/*!
@brief macro to briefly define a mapping between an enum and JSON
@def NLOHMANN_JSON_SERIALIZE_ENUM
@since version 3.4.0
*/
#define NLOHMANN_JSON_SERIALIZE_ENUM(ENUM_TYPE, ...) \
template<typename BasicJsonType> \
inline void to_json(BasicJsonType& j, const ENUM_TYPE& e) \
{ \
static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
auto it = std::find_if(std::begin(m), std::end(m), \
[e](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
{ \
return ej_pair.first == e; \
}); \
j = ((it != std::end(m)) ? it : std::begin(m))->second; \
} \
template<typename BasicJsonType> \
inline void from_json(const BasicJsonType& j, ENUM_TYPE& e) \
{ \
static_assert(std::is_enum<ENUM_TYPE>::value, #ENUM_TYPE " must be an enum!"); \
static const std::pair<ENUM_TYPE, BasicJsonType> m[] = __VA_ARGS__; \
auto it = std::find_if(std::begin(m), std::end(m), \
[j](const std::pair<ENUM_TYPE, BasicJsonType>& ej_pair) -> bool \
{ \
return ej_pair.second == j; \
}); \
e = ((it != std::end(m)) ? it : std::begin(m))->first; \
}
// Ugly macros to avoid uglier copy-paste when specializing basic_json. They
// may be removed in the future once the class is split.
#define NLOHMANN_BASIC_JSON_TPL_DECLARATION \
template<template<typename, typename, typename...> class ObjectType, \
template<typename, typename...> class ArrayType, \
class StringType, class BooleanType, class NumberIntegerType, \
class NumberUnsignedType, class NumberFloatType, \
template<typename> class AllocatorType, \
template<typename, typename = void> class JSONSerializer>
#define NLOHMANN_BASIC_JSON_TPL \
basic_json<ObjectType, ArrayType, StringType, BooleanType, \
NumberIntegerType, NumberUnsignedType, NumberFloatType, \
AllocatorType, JSONSerializer>