mirror of
https://github.com/nlohmann/json.git
synced 2026-11-02 19:05:35 +00:00
Niels Lohmann
57428501b5
basic_json::get<T>() of a boolean throws type_error.302 for exactly number_integer_t, number_unsigned_t and number_float_t (dedicated from_json() overloads) and gives 0/1 for every other arithmetic type. The view returned 0/1 for all of them, contradicting its documentation. The view now throws the same exception (same message, with path/bytes decoration) for these three types. basic_json is unchanged; its behavior is documented and pinned by a test. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
172 lines
6.9 KiB
C++
172 lines
6.9 KiB
C++
// __ _____ _____ _____
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// __| | __| | | | JSON for Modern C++
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// | | |__ | | | | | | version 3.12.0
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// |_____|_____|_____|_|___| https://github.com/nlohmann/json
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//
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// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
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// SPDX-License-Identifier: MIT
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#pragma once
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#include <cstddef> // nullptr_t, size_t
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#include <cstdint> // int64_t
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#include <map> // map
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#include <string> // basic_string
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#include <type_traits> // decay, enable_if, is_arithmetic, is_constructible, is_integral, is_same
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#include <unordered_map> // unordered_map
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#include <vector> // vector
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#include <nlohmann/json.hpp>
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#include <nlohmann/detail/view/document_data.hpp>
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#include <nlohmann/detail/view/errors.hpp>
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#include <nlohmann/detail/view/macro_scope.hpp>
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#include <nlohmann/detail/view/node.hpp>
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#include <nlohmann/detail/view/number.hpp>
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NLOHMANN_JSON_NAMESPACE_BEGIN
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namespace detail
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{
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namespace view
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{
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/// selects a conversion by its target type
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template<typename T>
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struct value_tag {};
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/// whether basic_json reads T with a dedicated from_json() overload that does
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/// not accept a boolean: exactly number_integer_t, number_unsigned_t and
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/// number_float_t (the other arithmetic types convert a boolean to 0 or 1)
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template<typename T, typename BasicJsonType>
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struct rejects_boolean : std::integral_constant < bool,
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std::is_same<T, typename BasicJsonType::number_integer_t>::value
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|| std::is_same<T, typename BasicJsonType::number_unsigned_t>::value
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|| std::is_same<T, typename BasicJsonType::number_float_t>::value >
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{};
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/// a boolean as T: 0 or 1
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template<typename T>
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NLOHMANN_VIEW_ALWAYS_INLINE T boolean_as(const document_data& /*d*/, const node& n, std::false_type /*rejects*/)
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{
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return static_cast<T>((n.flags & node_flags::is_true) != 0);
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}
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/// a boolean as number_integer_t, number_unsigned_t or number_float_t: type_error.302, as in basic_json
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template<typename T>
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[[noreturn]] NLOHMANN_VIEW_ALWAYS_INLINE T boolean_as(const document_data& d, const node& n, std::true_type /*rejects*/)
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{
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throw_type_error(error_site(&d, &n), exception_id::type_mismatch, "type must be number, but is ", value_type_name(static_cast<value_t>(n.kind)));
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}
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/*!
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@brief the number or boolean of a node converted to an arithmetic type
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As basic_json's get<T>() for arithmetic types: integers and floats are
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converted with static_cast, booleans give 0 or 1 (but throw type_error.302 for
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number_integer_t, number_unsigned_t and number_float_t, as basic_json does),
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and other types throw type_error.302.
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*/
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template<typename T, typename BasicJsonType>
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NLOHMANN_VIEW_ALWAYS_INLINE T arithmetic_value(const document_data& d, const node& n)
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{
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switch (static_cast<value_t>(n.kind))
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{
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case value_t::number_unsigned:
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return static_cast<T>(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(n)));
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case value_t::number_integer:
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return static_cast<T>(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(n))));
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case value_t::number_float:
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return static_cast<T>(float_value<typename BasicJsonType::number_float_t>(d, n));
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case value_t::boolean:
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return boolean_as<T>(d, n, rejects_boolean<T, BasicJsonType> {});
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case value_t::null:
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case value_t::object:
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case value_t::array:
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case value_t::string:
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case value_t::binary:
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case value_t::discarded:
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default:
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throw_type_error(error_site(&d, &n), exception_id::type_mismatch, "type must be number, but is ", value_type_name(static_cast<value_t>(n.kind)));
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}
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}
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/// std::vector from an array, element by element (type_error.302 otherwise)
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template<typename View, typename U, typename A>
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std::vector<U, A> vector_value(const View& v)
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{
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if (NLOHMANN_VIEW_UNLIKELY(!v.is_array()))
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{
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throw_type_error(site_of(v), exception_id::type_mismatch, "type must be array, but is ", v.type_name());
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}
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std::vector<U, A> r;
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r.reserve(v.size());
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for (const View e : v)
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{
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r.push_back(e.template get<U>());
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}
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return r;
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}
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/// a map with string keys from an object; with duplicate keys, the last
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/// value is kept, as parse() does (type_error.302 for other types)
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template<typename Map, typename View>
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Map map_value(const View& v)
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{
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if (NLOHMANN_VIEW_UNLIKELY(!v.is_object()))
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{
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throw_type_error(site_of(v), exception_id::type_mismatch, "type must be object, but is ", v.type_name());
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}
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Map r;
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for (auto it = v.begin(); it != v.end(); ++it)
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{
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const auto key = it.key();
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r[typename Map::key_type(key.data(), key.size())] = it.value().template get<typename Map::mapped_type>();
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}
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return r;
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}
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/// whether a map type is read member by member (its keys are made from
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/// characters and a length); other maps go through basic_json
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template<typename Key>
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struct is_string_key : std::is_constructible<Key, const char*, std::size_t> {};
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/// the arithmetic types arithmetic_value() converts to (bool has its own
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/// conversion)
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template<typename T>
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struct is_non_bool_arithmetic : conjunction<std::is_arithmetic<T>, negation<std::is_same<T, bool>>> {};
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/// the default values of value() other than C strings, which have their own
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/// overload (returning string_t)
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template<typename T>
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struct is_non_c_string_default : negation<std::is_same<typename std::decay<T>::type, const char*>> {};
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/// the integral types accepted as an array index by the edits of a document
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template<typename T>
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struct is_non_bool_integral : conjunction<std::is_integral<T>, negation<std::is_same<T, bool>>> {};
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/// whether View::get<T>() converts to T without materialize(); get_to()
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/// assigns these, and passes the others to from_json
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template<typename T, typename BasicJsonType, typename View>
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struct is_direct_value : std::integral_constant < bool,
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std::is_arithmetic<T>::value || std::is_same<T, std::nullptr_t>::value
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|| std::is_same<T, typename View::string_view_t>::value
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|| std::is_same<T, BasicJsonType>::value || std::is_same<T, View>::value >
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{};
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template<typename Traits, typename Alloc, typename BasicJsonType, typename View>
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struct is_direct_value<std::basic_string<char, Traits, Alloc>, BasicJsonType, View> : std::true_type {};
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// (vectors of these, which are faster than through from_json(), and containers
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// of views; other containers are read by the library's from_json())
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template<typename U, typename A, typename BasicJsonType, typename View>
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struct is_direct_value<std::vector<U, A>, BasicJsonType, View> : is_direct_value<U, BasicJsonType, View> {};
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template<typename K, typename C, typename A, typename BasicJsonType, typename View>
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struct is_direct_value<std::map<K, View, C, A>, BasicJsonType, View> : is_string_key<K> {};
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template<typename K, typename H, typename E, typename A, typename BasicJsonType, typename View>
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struct is_direct_value<std::unordered_map<K, View, H, E, A>, BasicJsonType, View> : is_string_key<K> {};
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} // namespace view
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} // namespace detail
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NLOHMANN_JSON_NAMESPACE_END
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