Disable std::swap specialization in C++20 and added a friend swap function

This commit is contained in:
Guillaume Racicot 2020-06-06 11:36:39 -04:00
parent 7444c7fa25
commit 225c8f150a
3 changed files with 76 additions and 2 deletions

View file

@ -20,7 +20,11 @@
#endif
// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#if (defined(__cplusplus) && __cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
#define JSON_HAS_CPP_20
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (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)

View file

@ -5865,6 +5865,34 @@ class basic_json
/*!
@brief exchanges the values
Exchanges the contents of the JSON value from @a left with those of @a right. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
invalidated. implemented as a friend function callable via ADL.
@param[in,out] left JSON value to exchange the contents with
@param[in,out] right JSON value to exchange the contents with
@complexity Constant.
@liveexample{The example below shows how JSON values can be swapped with
`swap()`.,swap__reference}
@since version 1.0.0
*/
friend void swap(reference left, reference right) noexcept (
std::is_nothrow_move_constructible<value_t>::value and
std::is_nothrow_move_assignable<value_t>::value and
std::is_nothrow_move_constructible<json_value>::value and
std::is_nothrow_move_assignable<json_value>::value
)
{
left.swap(right);
}
/*!
@brief exchanges the values
Exchanges the contents of a JSON array with those of @a other. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
@ -8635,6 +8663,9 @@ struct less<::nlohmann::detail::value_t>
}
};
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
/*!
@brief exchanges the values of two JSON objects
@ -8649,6 +8680,8 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
} // namespace std
/*!

View file

@ -2048,7 +2048,11 @@ JSON_HEDLEY_DIAGNOSTIC_POP
#endif
// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#if (defined(__cplusplus) && __cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
#define JSON_HAS_CPP_20
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (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)
@ -21628,6 +21632,34 @@ class basic_json
/*!
@brief exchanges the values
Exchanges the contents of the JSON value from @a left with those of @a right. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
invalidated. implemented as a friend function callable via ADL.
@param[in,out] left JSON value to exchange the contents with
@param[in,out] right JSON value to exchange the contents with
@complexity Constant.
@liveexample{The example below shows how JSON values can be swapped with
`swap()`.,swap__reference}
@since version 1.0.0
*/
friend void swap(reference left, reference right) noexcept (
std::is_nothrow_move_constructible<value_t>::value and
std::is_nothrow_move_assignable<value_t>::value and
std::is_nothrow_move_constructible<json_value>::value and
std::is_nothrow_move_assignable<json_value>::value
)
{
left.swap(right);
}
/*!
@brief exchanges the values
Exchanges the contents of a JSON array with those of @a other. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
@ -24398,6 +24430,9 @@ struct less<::nlohmann::detail::value_t>
}
};
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
/*!
@brief exchanges the values of two JSON objects
@ -24412,6 +24447,8 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
} // namespace std
/*!