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♻️ overwork std specializations

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Niels Lohmann 2021-11-03 15:20:44 +01:00
parent ca5ecc2945
commit 42c37d9c01
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3 changed files with 71 additions and 23 deletions
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21
include/nlohmann/json.hpp
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@ -4707,20 +4707,16 @@ std::string to_string(const NLOHMANN_BASIC_JSON_TPL& j)
// nonmember support //
///////////////////////
// specialization of std::swap, and std::hash
namespace std
{
/// hash value for JSON objects
template<>
struct hash<nlohmann::json>
template<typename BasicJsonType>
struct std::hash
{
/*!
@brief return a hash value for a JSON object
@since version 1.0.0
@since version 1.0.0, extended for arbitrary basic_json types in 3.10.5.
*/
std::size_t operator()(const nlohmann::json& j) const
std::size_t operator()(const BasicJsonType& j) const
{
return nlohmann::detail::hash(j);
}
@ -4730,7 +4726,7 @@ struct hash<nlohmann::json>
/// @note: do not remove the space after '<',
/// see https://github.com/nlohmann/json/pull/679
template<>
struct less<::nlohmann::detail::value_t>
struct std::less< ::nlohmann::detail::value_t>
{
/*!
@brief compare two value_t enum values
@ -4746,6 +4742,9 @@ struct less<::nlohmann::detail::value_t>
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
namespace std
{
/*!
@brief exchanges the values of two JSON objects
@ -4760,9 +4759,9 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
// namespace std
} // namespace std
#endif
/// @brief user-defined string literal for JSON values
/// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/

21
single_include/nlohmann/json.hpp
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@ -22208,20 +22208,16 @@ std::string to_string(const NLOHMANN_BASIC_JSON_TPL& j)
// nonmember support //
///////////////////////
// specialization of std::swap, and std::hash
namespace std
{
/// hash value for JSON objects
template<>
struct hash<nlohmann::json>
template<typename BasicJsonType>
struct std::hash
{
/*!
@brief return a hash value for a JSON object
@since version 1.0.0
@since version 1.0.0, extended for arbitrary basic_json types in 3.10.5.
*/
std::size_t operator()(const nlohmann::json& j) const
std::size_t operator()(const BasicJsonType& j) const
{
return nlohmann::detail::hash(j);
}
@ -22231,7 +22227,7 @@ struct hash<nlohmann::json>
/// @note: do not remove the space after '<',
/// see https://github.com/nlohmann/json/pull/679
template<>
struct less<::nlohmann::detail::value_t>
struct std::less< ::nlohmann::detail::value_t>
{
/*!
@brief compare two value_t enum values
@ -22247,6 +22243,9 @@ struct less<::nlohmann::detail::value_t>
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
namespace std
{
/*!
@brief exchanges the values of two JSON objects
@ -22261,9 +22260,9 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
// namespace std
} // namespace std
#endif
/// @brief user-defined string literal for JSON values
/// @sa https://json.nlohmann.me/api/basic_json/operator_literal_json/

52
test/src/unit-hash.cpp
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@ -31,10 +31,11 @@ SOFTWARE.
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using ordered_json = nlohmann::ordered_json;
#include <set>
TEST_CASE("hash")
TEST_CASE("hash<nlohmann::json>")
{
// Collect hashes for different JSON values and make sure that they are distinct
// We cannot compare against fixed values, because the implementation of
@ -82,3 +83,52 @@ TEST_CASE("hash")
CHECK(hashes.size() == 21);
}
TEST_CASE("hash<nlohmann::ordered_json>")
{
// Collect hashes for different JSON values and make sure that they are distinct
// We cannot compare against fixed values, because the implementation of
// std::hash may differ between compilers.
std::set<std::size_t> hashes;
// null
hashes.insert(std::hash<ordered_json> {}(ordered_json(nullptr)));
// boolean
hashes.insert(std::hash<ordered_json> {}(ordered_json(true)));
hashes.insert(std::hash<ordered_json> {}(ordered_json(false)));
// string
hashes.insert(std::hash<ordered_json> {}(ordered_json("")));
hashes.insert(std::hash<ordered_json> {}(ordered_json("foo")));
// number
hashes.insert(std::hash<ordered_json> {}(ordered_json(0)));
hashes.insert(std::hash<ordered_json> {}(ordered_json(unsigned(0))));
hashes.insert(std::hash<ordered_json> {}(ordered_json(-1)));
hashes.insert(std::hash<ordered_json> {}(ordered_json(0.0)));
hashes.insert(std::hash<ordered_json> {}(ordered_json(42.23)));
// array
hashes.insert(std::hash<ordered_json> {}(ordered_json::array()));
hashes.insert(std::hash<ordered_json> {}(ordered_json::array({1, 2, 3})));
// object
hashes.insert(std::hash<ordered_json> {}(ordered_json::object()));
hashes.insert(std::hash<ordered_json> {}(ordered_json::object({{"foo", "bar"}})));
// binary
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({})));
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({}, 0)));
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({}, 42)));
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({1, 2, 3})));
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({1, 2, 3}, 0)));
hashes.insert(std::hash<ordered_json> {}(ordered_json::binary({1, 2, 3}, 42)));
// discarded
hashes.insert(std::hash<ordered_json> {}(ordered_json(ordered_json::value_t::discarded)));
CHECK(hashes.size() == 21);
}