1 #pragma once
2
3 #include <algorithm> // transform
4 #include <array> // array
5 #include <ciso646> // and, not
6 #include <forward_list> // forward_list
7 #include <iterator> // inserter, front_inserter, end
8 #include <map> // map
9 #include <string> // string
10 #include <tuple> // tuple, make_tuple
11 #include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
12 #include <unordered_map> // unordered_map
13 #include <utility> // pair, declval
14 #include <valarray> // valarray
15
16 #include <nlohmann/detail/exceptions.hpp>
17 #include <nlohmann/detail/macro_scope.hpp>
18 #include <nlohmann/detail/meta/cpp_future.hpp>
19 #include <nlohmann/detail/meta/type_traits.hpp>
20 #include <nlohmann/detail/value_t.hpp>
21
22 namespace nlohmann
23 {
24 namespace detail
25 {
26 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename std::nullptr_t & n)27 void from_json(const BasicJsonType& j, typename std::nullptr_t& n)
28 {
29 if (JSON_HEDLEY_UNLIKELY(not j.is_null()))
30 {
31 JSON_THROW(type_error::create(302, "type must be null, but is " + std::string(j.type_name())));
32 }
33 n = nullptr;
34 }
35
36 // overloads for basic_json template parameters
37 template<typename BasicJsonType, typename ArithmeticType,
38 enable_if_t<std::is_arithmetic<ArithmeticType>::value and
39 not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
40 int> = 0>
get_arithmetic_value(const BasicJsonType & j,ArithmeticType & val)41 void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
42 {
43 switch (static_cast<value_t>(j))
44 {
45 case value_t::number_unsigned:
46 {
47 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
48 break;
49 }
50 case value_t::number_integer:
51 {
52 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
53 break;
54 }
55 case value_t::number_float:
56 {
57 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
58 break;
59 }
60
61 default:
62 JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
63 }
64 }
65
66 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename BasicJsonType::boolean_t & b)67 void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b)
68 {
69 if (JSON_HEDLEY_UNLIKELY(not j.is_boolean()))
70 {
71 JSON_THROW(type_error::create(302, "type must be boolean, but is " + std::string(j.type_name())));
72 }
73 b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
74 }
75
76 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename BasicJsonType::string_t & s)77 void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s)
78 {
79 if (JSON_HEDLEY_UNLIKELY(not j.is_string()))
80 {
81 JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
82 }
83 s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
84 }
85
86 template <
87 typename BasicJsonType, typename ConstructibleStringType,
88 enable_if_t <
89 is_constructible_string_type<BasicJsonType, ConstructibleStringType>::value and
90 not std::is_same<typename BasicJsonType::string_t,
91 ConstructibleStringType>::value,
92 int > = 0 >
from_json(const BasicJsonType & j,ConstructibleStringType & s)93 void from_json(const BasicJsonType& j, ConstructibleStringType& s)
94 {
95 if (JSON_HEDLEY_UNLIKELY(not j.is_string()))
96 {
97 JSON_THROW(type_error::create(302, "type must be string, but is " + std::string(j.type_name())));
98 }
99
100 s = *j.template get_ptr<const typename BasicJsonType::string_t*>();
101 }
102
103 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename BasicJsonType::number_float_t & val)104 void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val)
105 {
106 get_arithmetic_value(j, val);
107 }
108
109 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename BasicJsonType::number_unsigned_t & val)110 void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
111 {
112 get_arithmetic_value(j, val);
113 }
114
115 template<typename BasicJsonType>
from_json(const BasicJsonType & j,typename BasicJsonType::number_integer_t & val)116 void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val)
117 {
118 get_arithmetic_value(j, val);
119 }
120
121 template<typename BasicJsonType, typename EnumType,
122 enable_if_t<std::is_enum<EnumType>::value, int> = 0>
from_json(const BasicJsonType & j,EnumType & e)123 void from_json(const BasicJsonType& j, EnumType& e)
124 {
125 typename std::underlying_type<EnumType>::type val;
126 get_arithmetic_value(j, val);
127 e = static_cast<EnumType>(val);
128 }
129
130 // forward_list doesn't have an insert method
131 template<typename BasicJsonType, typename T, typename Allocator,
132 enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
from_json(const BasicJsonType & j,std::forward_list<T,Allocator> & l)133 void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l)
134 {
135 if (JSON_HEDLEY_UNLIKELY(not j.is_array()))
136 {
137 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
138 }
139 l.clear();
140 std::transform(j.rbegin(), j.rend(),
141 std::front_inserter(l), [](const BasicJsonType & i)
142 {
143 return i.template get<T>();
144 });
145 }
146
147 // valarray doesn't have an insert method
148 template<typename BasicJsonType, typename T,
149 enable_if_t<std::is_convertible<BasicJsonType, T>::value, int> = 0>
from_json(const BasicJsonType & j,std::valarray<T> & l)150 void from_json(const BasicJsonType& j, std::valarray<T>& l)
151 {
152 if (JSON_HEDLEY_UNLIKELY(not j.is_array()))
153 {
154 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
155 }
156 l.resize(j.size());
157 std::copy(j.begin(), j.end(), std::begin(l));
158 }
159
160 template <typename BasicJsonType, typename T, std::size_t N>
from_json(const BasicJsonType & j,T (& arr)[N])161 auto from_json(const BasicJsonType& j, T (&arr)[N])
162 -> decltype(j.template get<T>(), void())
163 {
164 for (std::size_t i = 0; i < N; ++i)
165 {
166 arr[i] = j.at(i).template get<T>();
167 }
168 }
169
170 template<typename BasicJsonType>
from_json_array_impl(const BasicJsonType & j,typename BasicJsonType::array_t & arr,priority_tag<3>)171 void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
172 {
173 arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
174 }
175
176 template <typename BasicJsonType, typename T, std::size_t N>
from_json_array_impl(const BasicJsonType & j,std::array<T,N> & arr,priority_tag<2>)177 auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
178 priority_tag<2> /*unused*/)
179 -> decltype(j.template get<T>(), void())
180 {
181 for (std::size_t i = 0; i < N; ++i)
182 {
183 arr[i] = j.at(i).template get<T>();
184 }
185 }
186
187 template<typename BasicJsonType, typename ConstructibleArrayType>
from_json_array_impl(const BasicJsonType & j,ConstructibleArrayType & arr,priority_tag<1>)188 auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
189 -> decltype(
190 arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
191 j.template get<typename ConstructibleArrayType::value_type>(),
192 void())
193 {
194 using std::end;
195
196 ConstructibleArrayType ret;
197 ret.reserve(j.size());
198 std::transform(j.begin(), j.end(),
199 std::inserter(ret, end(ret)), [](const BasicJsonType & i)
200 {
201 // get<BasicJsonType>() returns *this, this won't call a from_json
202 // method when value_type is BasicJsonType
203 return i.template get<typename ConstructibleArrayType::value_type>();
204 });
205 arr = std::move(ret);
206 }
207
208 template <typename BasicJsonType, typename ConstructibleArrayType>
from_json_array_impl(const BasicJsonType & j,ConstructibleArrayType & arr,priority_tag<0>)209 void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
210 priority_tag<0> /*unused*/)
211 {
212 using std::end;
213
214 ConstructibleArrayType ret;
215 std::transform(
216 j.begin(), j.end(), std::inserter(ret, end(ret)),
217 [](const BasicJsonType & i)
218 {
219 // get<BasicJsonType>() returns *this, this won't call a from_json
220 // method when value_type is BasicJsonType
221 return i.template get<typename ConstructibleArrayType::value_type>();
222 });
223 arr = std::move(ret);
224 }
225
226 template <typename BasicJsonType, typename ConstructibleArrayType,
227 enable_if_t <
228 is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value and
229 not is_constructible_object_type<BasicJsonType, ConstructibleArrayType>::value and
230 not is_constructible_string_type<BasicJsonType, ConstructibleArrayType>::value and
231 not is_basic_json<ConstructibleArrayType>::value,
232 int > = 0 >
233
from_json(const BasicJsonType & j,ConstructibleArrayType & arr)234 auto from_json(const BasicJsonType& j, ConstructibleArrayType& arr)
235 -> decltype(from_json_array_impl(j, arr, priority_tag<3> {}),
236 j.template get<typename ConstructibleArrayType::value_type>(),
237 void())
238 {
239 if (JSON_HEDLEY_UNLIKELY(not j.is_array()))
240 {
241 JSON_THROW(type_error::create(302, "type must be array, but is " +
242 std::string(j.type_name())));
243 }
244
245 from_json_array_impl(j, arr, priority_tag<3> {});
246 }
247
248 template<typename BasicJsonType, typename ConstructibleObjectType,
249 enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
from_json(const BasicJsonType & j,ConstructibleObjectType & obj)250 void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
251 {
252 if (JSON_HEDLEY_UNLIKELY(not j.is_object()))
253 {
254 JSON_THROW(type_error::create(302, "type must be object, but is " + std::string(j.type_name())));
255 }
256
257 ConstructibleObjectType ret;
258 auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
259 using value_type = typename ConstructibleObjectType::value_type;
260 std::transform(
261 inner_object->begin(), inner_object->end(),
262 std::inserter(ret, ret.begin()),
263 [](typename BasicJsonType::object_t::value_type const & p)
264 {
265 return value_type(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
266 });
267 obj = std::move(ret);
268 }
269
270 // overload for arithmetic types, not chosen for basic_json template arguments
271 // (BooleanType, etc..); note: Is it really necessary to provide explicit
272 // overloads for boolean_t etc. in case of a custom BooleanType which is not
273 // an arithmetic type?
274 template<typename BasicJsonType, typename ArithmeticType,
275 enable_if_t <
276 std::is_arithmetic<ArithmeticType>::value and
277 not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and
278 not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and
279 not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and
280 not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value,
281 int> = 0>
from_json(const BasicJsonType & j,ArithmeticType & val)282 void from_json(const BasicJsonType& j, ArithmeticType& val)
283 {
284 switch (static_cast<value_t>(j))
285 {
286 case value_t::number_unsigned:
287 {
288 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
289 break;
290 }
291 case value_t::number_integer:
292 {
293 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>());
294 break;
295 }
296 case value_t::number_float:
297 {
298 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>());
299 break;
300 }
301 case value_t::boolean:
302 {
303 val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>());
304 break;
305 }
306
307 default:
308 JSON_THROW(type_error::create(302, "type must be number, but is " + std::string(j.type_name())));
309 }
310 }
311
312 template<typename BasicJsonType, typename A1, typename A2>
from_json(const BasicJsonType & j,std::pair<A1,A2> & p)313 void from_json(const BasicJsonType& j, std::pair<A1, A2>& p)
314 {
315 p = {j.at(0).template get<A1>(), j.at(1).template get<A2>()};
316 }
317
318 template<typename BasicJsonType, typename Tuple, std::size_t... Idx>
from_json_tuple_impl(const BasicJsonType & j,Tuple & t,index_sequence<Idx...>)319 void from_json_tuple_impl(const BasicJsonType& j, Tuple& t, index_sequence<Idx...> /*unused*/)
320 {
321 t = std::make_tuple(j.at(Idx).template get<typename std::tuple_element<Idx, Tuple>::type>()...);
322 }
323
324 template<typename BasicJsonType, typename... Args>
from_json(const BasicJsonType & j,std::tuple<Args...> & t)325 void from_json(const BasicJsonType& j, std::tuple<Args...>& t)
326 {
327 from_json_tuple_impl(j, t, index_sequence_for<Args...> {});
328 }
329
330 template <typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
331 typename = enable_if_t<not std::is_constructible<
332 typename BasicJsonType::string_t, Key>::value>>
from_json(const BasicJsonType & j,std::map<Key,Value,Compare,Allocator> & m)333 void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
334 {
335 if (JSON_HEDLEY_UNLIKELY(not j.is_array()))
336 {
337 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
338 }
339 m.clear();
340 for (const auto& p : j)
341 {
342 if (JSON_HEDLEY_UNLIKELY(not p.is_array()))
343 {
344 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
345 }
346 m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
347 }
348 }
349
350 template <typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
351 typename = enable_if_t<not std::is_constructible<
352 typename BasicJsonType::string_t, Key>::value>>
from_json(const BasicJsonType & j,std::unordered_map<Key,Value,Hash,KeyEqual,Allocator> & m)353 void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
354 {
355 if (JSON_HEDLEY_UNLIKELY(not j.is_array()))
356 {
357 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
358 }
359 m.clear();
360 for (const auto& p : j)
361 {
362 if (JSON_HEDLEY_UNLIKELY(not p.is_array()))
363 {
364 JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
365 }
366 m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
367 }
368 }
369
370 struct from_json_fn
371 {
372 template<typename BasicJsonType, typename T>
operator ()nlohmann::detail::from_json_fn373 auto operator()(const BasicJsonType& j, T& val) const
374 noexcept(noexcept(from_json(j, val)))
375 -> decltype(from_json(j, val), void())
376 {
377 return from_json(j, val);
378 }
379 };
380 } // namespace detail
381
382 /// namespace to hold default `from_json` function
383 /// to see why this is required:
384 /// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
385 namespace
386 {
387 constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
388 } // namespace
389 } // namespace nlohmann
390