mirror of
https://github.com/nlohmann/json.git
synced 2026-10-18 12:08:12 +00:00
Niels Lohmann
7b755737b4
From gregmarr's review of #5622: - count() counts every member with the key, so count(key) > 1 detects duplicate keys; it was contains() as 0/1 before. - get_to() passes types that get<T>() does not convert directly to from_json with the existing value, as basic_json::get_to() does, so that a from_json which sets only the fields present keeps the others. - array_index() checks the empty token and "-" first; the results are unchanged. - Docs: no "if an exception is thrown" where a view never changes anything; the borrowed source must also stay unmodified; items() on a temporary view is safe; back()/front() notes shortened; the basic_json see-also entries say how the view's results can differ. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
131 lines
4.7 KiB
C++
131 lines
4.7 KiB
C++
// __ _____ _____ _____
|
|
// __| | __| | | | JSON for Modern C++
|
|
// | | |__ | | | | | | version 3.12.0
|
|
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
|
|
//
|
|
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
|
|
// SPDX-License-Identifier: MIT
|
|
|
|
#pragma once
|
|
|
|
#include <cstddef> // nullptr_t, size_t
|
|
#include <cstdint> // int64_t
|
|
#include <map> // map
|
|
#include <string> // basic_string
|
|
#include <type_traits> // enable_if, is_constructible
|
|
#include <unordered_map> // unordered_map
|
|
#include <vector> // vector
|
|
|
|
#include <nlohmann/json.hpp>
|
|
#include <nlohmann/detail/view/document_data.hpp>
|
|
#include <nlohmann/detail/view/errors.hpp>
|
|
#include <nlohmann/detail/view/macro_scope.hpp>
|
|
#include <nlohmann/detail/view/node.hpp>
|
|
#include <nlohmann/detail/view/number.hpp>
|
|
|
|
NLOHMANN_JSON_NAMESPACE_BEGIN
|
|
namespace detail
|
|
{
|
|
namespace view
|
|
{
|
|
|
|
/// selects a conversion by its target type
|
|
template<typename T>
|
|
struct value_tag {};
|
|
|
|
/*!
|
|
@brief the number or boolean of a node converted to an arithmetic type
|
|
|
|
As basic_json's get<T>() for arithmetic types: integers and floats are
|
|
converted with static_cast, booleans give 0 or 1, and other types throw
|
|
type_error.302.
|
|
*/
|
|
template<typename T, typename BasicJsonType>
|
|
NLOHMANN_VIEW_ALWAYS_INLINE T arithmetic_value(const document_data& d, const node& n)
|
|
{
|
|
switch (static_cast<value_t>(n.kind))
|
|
{
|
|
case value_t::number_unsigned:
|
|
return static_cast<T>(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(n)));
|
|
case value_t::number_integer:
|
|
return static_cast<T>(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(n))));
|
|
case value_t::number_float:
|
|
return static_cast<T>(float_value<typename BasicJsonType::number_float_t>(d.str(n), n));
|
|
case value_t::boolean:
|
|
return static_cast<T>((n.flags & node_flags::is_true) != 0);
|
|
case value_t::null:
|
|
case value_t::object:
|
|
case value_t::array:
|
|
case value_t::string:
|
|
case value_t::binary:
|
|
case value_t::discarded:
|
|
default:
|
|
throw_type_error(302, "type must be number, but is ", value_type_name(static_cast<value_t>(n.kind)));
|
|
}
|
|
}
|
|
|
|
/// std::vector from an array, element by element (type_error.302 otherwise)
|
|
template<typename View, typename U, typename A>
|
|
std::vector<U, A> vector_value(const View& v)
|
|
{
|
|
if (NLOHMANN_VIEW_UNLIKELY(!v.is_array()))
|
|
{
|
|
throw_type_error(302, "type must be array, but is ", v.type_name());
|
|
}
|
|
std::vector<U, A> r;
|
|
r.reserve(v.size());
|
|
for (const View e : v)
|
|
{
|
|
r.push_back(e.template get<U>());
|
|
}
|
|
return r;
|
|
}
|
|
|
|
/// a map with string keys from an object; with duplicate keys, the last
|
|
/// value is kept, as parse() does (type_error.302 for other types)
|
|
template<typename Map, typename View>
|
|
Map map_value(const View& v)
|
|
{
|
|
if (NLOHMANN_VIEW_UNLIKELY(!v.is_object()))
|
|
{
|
|
throw_type_error(302, "type must be object, but is ", v.type_name());
|
|
}
|
|
Map r;
|
|
for (auto it = v.begin(); it != v.end(); ++it)
|
|
{
|
|
const auto key = it.key();
|
|
r[typename Map::key_type(key.data(), key.size())] = it.value().template get<typename Map::mapped_type>();
|
|
}
|
|
return r;
|
|
}
|
|
|
|
/// whether a map type is read member by member (its keys are made from
|
|
/// characters and a length); other maps go through basic_json
|
|
template<typename Key>
|
|
struct is_string_key : std::is_constructible<Key, const char*, std::size_t> {};
|
|
|
|
/// whether View::get<T>() converts to T without materialize(); get_to()
|
|
/// assigns these, and passes the others to from_json
|
|
template<typename T, typename BasicJsonType, typename View>
|
|
struct is_direct_value : std::integral_constant < bool,
|
|
std::is_arithmetic<T>::value || std::is_same<T, std::nullptr_t>::value
|
|
|| std::is_same<T, typename View::string_view_t>::value
|
|
|| std::is_same<T, BasicJsonType>::value || std::is_same<T, View>::value >
|
|
{};
|
|
|
|
template<typename Traits, typename Alloc, typename BasicJsonType, typename View>
|
|
struct is_direct_value<std::basic_string<char, Traits, Alloc>, BasicJsonType, View> : std::true_type {};
|
|
|
|
template<typename U, typename A, typename BasicJsonType, typename View>
|
|
struct is_direct_value<std::vector<U, A>, BasicJsonType, View> : std::true_type {};
|
|
|
|
template<typename K, typename V, typename C, typename A, typename BasicJsonType, typename View>
|
|
struct is_direct_value<std::map<K, V, C, A>, BasicJsonType, View> : is_string_key<K> {};
|
|
|
|
template<typename K, typename V, typename H, typename E, typename A, typename BasicJsonType, typename View>
|
|
struct is_direct_value<std::unordered_map<K, V, H, E, A>, BasicJsonType, View> : is_string_key<K> {};
|
|
|
|
} // namespace view
|
|
} // namespace detail
|
|
NLOHMANN_JSON_NAMESPACE_END
|