Jim Flynn | 6217c3d | 2022-06-14 10:58:23 +0100 | [diff] [blame] | 1 | // |
| 2 | // Copyright (c) MapBox All rights reserved. |
| 3 | // SPDX-License-Identifier: BSD-3-Clause |
| 4 | // |
| 5 | |
James Ward | 22a4e15 | 2020-09-25 11:43:21 +0100 | [diff] [blame] | 6 | #ifndef MAPBOX_UTIL_VARIANT_HPP |
| 7 | #define MAPBOX_UTIL_VARIANT_HPP |
| 8 | |
| 9 | #include <cassert> |
| 10 | #include <cstddef> // size_t |
| 11 | #include <new> // operator new |
| 12 | #include <stdexcept> // runtime_error |
| 13 | #include <string> |
| 14 | #include <tuple> |
| 15 | #include <type_traits> |
| 16 | #include <typeinfo> |
| 17 | #include <utility> |
| 18 | #include <functional> |
| 19 | #include <limits> |
| 20 | |
| 21 | #include <mapbox/recursive_wrapper.hpp> |
| 22 | #include <mapbox/variant_visitor.hpp> |
| 23 | |
| 24 | // clang-format off |
| 25 | // [[deprecated]] is only available in C++14, use this for the time being |
| 26 | #if __cplusplus <= 201103L |
| 27 | # ifdef __GNUC__ |
| 28 | # define MAPBOX_VARIANT_DEPRECATED __attribute__((deprecated)) |
| 29 | # elif defined(_MSC_VER) |
| 30 | # define MAPBOX_VARIANT_DEPRECATED __declspec(deprecated) |
| 31 | # else |
| 32 | # define MAPBOX_VARIANT_DEPRECATED |
| 33 | # endif |
| 34 | #else |
| 35 | # define MAPBOX_VARIANT_DEPRECATED [[deprecated]] |
| 36 | #endif |
| 37 | |
| 38 | |
| 39 | #ifdef _MSC_VER |
| 40 | // https://msdn.microsoft.com/en-us/library/bw1hbe6y.aspx |
| 41 | # ifdef NDEBUG |
| 42 | # define VARIANT_INLINE __forceinline |
| 43 | # else |
| 44 | # define VARIANT_INLINE //__declspec(noinline) |
| 45 | # endif |
| 46 | #else |
| 47 | # ifdef NDEBUG |
| 48 | # define VARIANT_INLINE //inline __attribute__((always_inline)) |
| 49 | # else |
| 50 | # define VARIANT_INLINE __attribute__((noinline)) |
| 51 | # endif |
| 52 | #endif |
| 53 | // clang-format on |
| 54 | |
| 55 | // Exceptions |
| 56 | #if defined( __EXCEPTIONS) || defined( _MSC_VER) |
| 57 | #define HAS_EXCEPTIONS |
| 58 | #endif |
| 59 | |
| 60 | #define VARIANT_MAJOR_VERSION 1 |
| 61 | #define VARIANT_MINOR_VERSION 1 |
| 62 | #define VARIANT_PATCH_VERSION 0 |
| 63 | |
| 64 | #define VARIANT_VERSION (VARIANT_MAJOR_VERSION * 100000) + (VARIANT_MINOR_VERSION * 100) + (VARIANT_PATCH_VERSION) |
| 65 | |
| 66 | namespace mapbox { |
| 67 | namespace util { |
| 68 | |
| 69 | // XXX This should derive from std::logic_error instead of std::runtime_error. |
| 70 | // See https://github.com/mapbox/variant/issues/48 for details. |
| 71 | class bad_variant_access : public std::runtime_error |
| 72 | { |
| 73 | |
| 74 | public: |
| 75 | explicit bad_variant_access(const std::string& what_arg) |
| 76 | : runtime_error(what_arg) {} |
| 77 | |
| 78 | explicit bad_variant_access(const char* what_arg) |
| 79 | : runtime_error(what_arg) {} |
| 80 | |
| 81 | }; // class bad_variant_access |
| 82 | |
| 83 | #if !defined(MAPBOX_VARIANT_MINIMIZE_SIZE) |
| 84 | using type_index_t = unsigned int; |
| 85 | #else |
| 86 | #if defined(MAPBOX_VARIANT_OPTIMIZE_FOR_SPEED) |
| 87 | using type_index_t = std::uint_fast8_t; |
| 88 | #else |
| 89 | using type_index_t = std::uint_least8_t; |
| 90 | #endif |
| 91 | #endif |
| 92 | |
| 93 | namespace detail { |
| 94 | |
| 95 | static constexpr type_index_t invalid_value = type_index_t(-1); |
| 96 | |
| 97 | template <typename T, typename... Types> |
| 98 | struct direct_type; |
| 99 | |
| 100 | template <typename T, typename First, typename... Types> |
| 101 | struct direct_type<T, First, Types...> |
| 102 | { |
| 103 | static constexpr type_index_t index = std::is_same<T, First>::value |
| 104 | ? sizeof...(Types) |
| 105 | : direct_type<T, Types...>::index; |
| 106 | }; |
| 107 | |
| 108 | template <typename T> |
| 109 | struct direct_type<T> |
| 110 | { |
| 111 | static constexpr type_index_t index = invalid_value; |
| 112 | }; |
| 113 | |
| 114 | #if __cpp_lib_logical_traits >= 201510L |
| 115 | |
| 116 | using std::conjunction; |
| 117 | using std::disjunction; |
| 118 | |
| 119 | #else |
| 120 | |
| 121 | template <typename...> |
| 122 | struct conjunction : std::true_type {}; |
| 123 | |
| 124 | template <typename B1> |
| 125 | struct conjunction<B1> : B1 {}; |
| 126 | |
| 127 | template <typename B1, typename B2> |
| 128 | struct conjunction<B1, B2> : std::conditional<B1::value, B2, B1>::type {}; |
| 129 | |
| 130 | template <typename B1, typename... Bs> |
| 131 | struct conjunction<B1, Bs...> : std::conditional<B1::value, conjunction<Bs...>, B1>::type {}; |
| 132 | |
| 133 | template <typename...> |
| 134 | struct disjunction : std::false_type {}; |
| 135 | |
| 136 | template <typename B1> |
| 137 | struct disjunction<B1> : B1 {}; |
| 138 | |
| 139 | template <typename B1, typename B2> |
| 140 | struct disjunction<B1, B2> : std::conditional<B1::value, B1, B2>::type {}; |
| 141 | |
| 142 | template <typename B1, typename... Bs> |
| 143 | struct disjunction<B1, Bs...> : std::conditional<B1::value, B1, disjunction<Bs...>>::type {}; |
| 144 | |
| 145 | #endif |
| 146 | |
| 147 | template <typename T, typename... Types> |
| 148 | struct convertible_type; |
| 149 | |
| 150 | template <typename T, typename First, typename... Types> |
| 151 | struct convertible_type<T, First, Types...> |
| 152 | { |
| 153 | static constexpr type_index_t index = std::is_convertible<T, First>::value |
| 154 | ? disjunction<std::is_convertible<T, Types>...>::value ? invalid_value : sizeof...(Types) |
| 155 | : convertible_type<T, Types...>::index; |
| 156 | }; |
| 157 | |
| 158 | template <typename T> |
| 159 | struct convertible_type<T> |
| 160 | { |
| 161 | static constexpr type_index_t index = invalid_value; |
| 162 | }; |
| 163 | |
| 164 | template <typename T, typename... Types> |
| 165 | struct value_traits |
| 166 | { |
| 167 | using value_type = typename std::remove_const<typename std::remove_reference<T>::type>::type; |
| 168 | using value_type_wrapper = recursive_wrapper<value_type>; |
| 169 | static constexpr type_index_t direct_index = direct_type<value_type, Types...>::index; |
| 170 | static constexpr bool is_direct = direct_index != invalid_value; |
| 171 | static constexpr type_index_t index_direct_or_wrapper = is_direct ? direct_index : direct_type<value_type_wrapper, Types...>::index; |
| 172 | static constexpr bool is_direct_or_wrapper = index_direct_or_wrapper != invalid_value; |
| 173 | static constexpr type_index_t index = is_direct_or_wrapper ? index_direct_or_wrapper : convertible_type<value_type, Types...>::index; |
| 174 | static constexpr bool is_valid = index != invalid_value; |
| 175 | static constexpr type_index_t tindex = is_valid ? sizeof...(Types)-index : 0; |
| 176 | using target_type = typename std::tuple_element<tindex, std::tuple<void, Types...>>::type; |
| 177 | }; |
| 178 | |
| 179 | template <typename Src, typename Dest> |
| 180 | struct copy_cvref |
| 181 | { |
| 182 | using type = Dest; |
| 183 | }; |
| 184 | |
| 185 | template <typename Src, typename Dest> |
| 186 | struct copy_cvref<Src const&, Dest> |
| 187 | { |
| 188 | using type = Dest const&; |
| 189 | }; |
| 190 | |
| 191 | template <typename Src, typename Dest> |
| 192 | struct copy_cvref<Src&, Dest> |
| 193 | { |
| 194 | using type = Dest&; |
| 195 | }; |
| 196 | |
| 197 | template <typename Src, typename Dest> |
| 198 | struct copy_cvref<Src&&, Dest> |
| 199 | { |
| 200 | using type = Dest&&; |
| 201 | }; |
| 202 | |
| 203 | template <typename F, typename = void> |
| 204 | struct deduced_result_type |
| 205 | {}; |
| 206 | |
| 207 | template <typename F, typename... Args> |
| 208 | struct deduced_result_type<F(Args...), decltype((void)std::declval<F>()(std::declval<Args>()...))> |
| 209 | { |
| 210 | using type = decltype(std::declval<F>()(std::declval<Args>()...)); |
| 211 | }; |
| 212 | |
| 213 | template <typename F, typename = void> |
| 214 | struct visitor_result_type : deduced_result_type<F> |
| 215 | {}; |
| 216 | |
| 217 | // specialization for explicit result_type member in visitor class |
| 218 | template <typename F, typename... Args> |
| 219 | struct visitor_result_type<F(Args...), decltype((void)std::declval<typename std::decay<F>::type::result_type>())> |
| 220 | { |
| 221 | using type = typename std::decay<F>::type::result_type; |
| 222 | }; |
| 223 | |
| 224 | template <typename F, typename T> |
| 225 | using result_of_unary_visit = typename visitor_result_type<F&&(T&&)>::type; |
| 226 | |
| 227 | template <typename F, typename T> |
| 228 | using result_of_binary_visit = typename visitor_result_type<F&&(T&&, T&&)>::type; |
| 229 | |
| 230 | template <type_index_t arg1, type_index_t... others> |
| 231 | struct static_max; |
| 232 | |
| 233 | template <type_index_t arg> |
| 234 | struct static_max<arg> |
| 235 | { |
| 236 | static const type_index_t value = arg; |
| 237 | }; |
| 238 | |
| 239 | template <type_index_t arg1, type_index_t arg2, type_index_t... others> |
| 240 | struct static_max<arg1, arg2, others...> |
| 241 | { |
| 242 | static const type_index_t value = arg1 >= arg2 ? static_max<arg1, others...>::value : static_max<arg2, others...>::value; |
| 243 | }; |
| 244 | |
| 245 | template <typename... Types> |
| 246 | struct variant_helper; |
| 247 | |
| 248 | template <typename T, typename... Types> |
| 249 | struct variant_helper<T, Types...> |
| 250 | { |
| 251 | VARIANT_INLINE static void destroy(const type_index_t type_index, void* data) |
| 252 | { |
| 253 | if (type_index == sizeof...(Types)) |
| 254 | { |
| 255 | reinterpret_cast<T*>(data)->~T(); |
| 256 | } |
| 257 | else |
| 258 | { |
| 259 | variant_helper<Types...>::destroy(type_index, data); |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | VARIANT_INLINE static void move(const type_index_t old_type_index, void* old_value, void* new_value) |
| 264 | { |
| 265 | if (old_type_index == sizeof...(Types)) |
| 266 | { |
| 267 | new (new_value) T(std::move(*reinterpret_cast<T*>(old_value))); |
| 268 | } |
| 269 | else |
| 270 | { |
| 271 | variant_helper<Types...>::move(old_type_index, old_value, new_value); |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | VARIANT_INLINE static void copy(const type_index_t old_type_index, const void* old_value, void* new_value) |
| 276 | { |
| 277 | if (old_type_index == sizeof...(Types)) |
| 278 | { |
| 279 | new (new_value) T(*reinterpret_cast<const T*>(old_value)); |
| 280 | } |
| 281 | else |
| 282 | { |
| 283 | variant_helper<Types...>::copy(old_type_index, old_value, new_value); |
| 284 | } |
| 285 | } |
| 286 | }; |
| 287 | |
| 288 | template <> |
| 289 | struct variant_helper<> |
| 290 | { |
| 291 | VARIANT_INLINE static void destroy(const type_index_t, void*) {} |
| 292 | VARIANT_INLINE static void move(const type_index_t, void*, void*) {} |
| 293 | VARIANT_INLINE static void copy(const type_index_t, const void*, void*) {} |
| 294 | }; |
| 295 | |
| 296 | template <typename T> |
| 297 | struct unwrapper |
| 298 | { |
| 299 | using value_type = T; |
| 300 | |
| 301 | template <typename V> |
| 302 | static auto apply(typename std::remove_reference<V>::type& var) |
| 303 | -> typename std::enable_if<std::is_lvalue_reference<V>::value, |
| 304 | decltype(var.template get_unchecked<T>())>::type |
| 305 | { |
| 306 | return var.template get_unchecked<T>(); |
| 307 | } |
| 308 | |
| 309 | template <typename V> |
| 310 | static auto apply(typename std::remove_reference<V>::type& var) |
| 311 | -> typename std::enable_if<!std::is_lvalue_reference<V>::value, |
| 312 | decltype(std::move(var.template get_unchecked<T>()))>::type |
| 313 | { |
| 314 | return std::move(var.template get_unchecked<T>()); |
| 315 | } |
| 316 | }; |
| 317 | |
| 318 | template <typename T> |
| 319 | struct unwrapper<recursive_wrapper<T>> : unwrapper<T> |
| 320 | {}; |
| 321 | |
| 322 | template <typename T> |
| 323 | struct unwrapper<std::reference_wrapper<T>> : unwrapper<T> |
| 324 | {}; |
| 325 | |
| 326 | template <typename R, typename... Types> |
| 327 | struct dispatcher; |
| 328 | |
| 329 | template <typename R, typename T, typename... Types> |
| 330 | struct dispatcher<R, T, Types...> |
| 331 | { |
| 332 | template <typename V, typename F> |
| 333 | VARIANT_INLINE static R apply(V&& v, F&& f) |
| 334 | { |
| 335 | if (v.template is<T>()) |
| 336 | { |
| 337 | return std::forward<F>(f)(unwrapper<T>::template apply<V>(v)); |
| 338 | } |
| 339 | else |
| 340 | { |
| 341 | return dispatcher<R, Types...>::apply(std::forward<V>(v), std::forward<F>(f)); |
| 342 | } |
| 343 | } |
| 344 | }; |
| 345 | |
| 346 | template <typename R, typename T> |
| 347 | struct dispatcher<R, T> |
| 348 | { |
| 349 | template <typename V, typename F> |
| 350 | VARIANT_INLINE static R apply(V&& v, F&& f) |
| 351 | { |
| 352 | return std::forward<F>(f)(unwrapper<T>::template apply<V>(v)); |
| 353 | } |
| 354 | }; |
| 355 | |
| 356 | template <typename R, typename T, typename... Types> |
| 357 | struct binary_dispatcher_rhs; |
| 358 | |
| 359 | template <typename R, typename T0, typename T1, typename... Types> |
| 360 | struct binary_dispatcher_rhs<R, T0, T1, Types...> |
| 361 | { |
| 362 | template <typename V, typename F> |
| 363 | VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f) |
| 364 | { |
| 365 | if (rhs.template is<T1>()) // call binary functor |
| 366 | { |
| 367 | return std::forward<F>(f)(unwrapper<T0>::template apply<V>(lhs), |
| 368 | unwrapper<T1>::template apply<V>(rhs)); |
| 369 | } |
| 370 | else |
| 371 | { |
| 372 | return binary_dispatcher_rhs<R, T0, Types...>::apply(std::forward<V>(lhs), |
| 373 | std::forward<V>(rhs), |
| 374 | std::forward<F>(f)); |
| 375 | } |
| 376 | } |
| 377 | }; |
| 378 | |
| 379 | template <typename R, typename T0, typename T1> |
| 380 | struct binary_dispatcher_rhs<R, T0, T1> |
| 381 | { |
| 382 | template <typename V, typename F> |
| 383 | VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f) |
| 384 | { |
| 385 | return std::forward<F>(f)(unwrapper<T0>::template apply<V>(lhs), |
| 386 | unwrapper<T1>::template apply<V>(rhs)); |
| 387 | } |
| 388 | }; |
| 389 | |
| 390 | template <typename R, typename T, typename... Types> |
| 391 | struct binary_dispatcher_lhs; |
| 392 | |
| 393 | template <typename R, typename T0, typename T1, typename... Types> |
| 394 | struct binary_dispatcher_lhs<R, T0, T1, Types...> |
| 395 | { |
| 396 | template <typename V, typename F> |
| 397 | VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f) |
| 398 | { |
| 399 | if (lhs.template is<T1>()) // call binary functor |
| 400 | { |
| 401 | return std::forward<F>(f)(unwrapper<T1>::template apply<V>(lhs), |
| 402 | unwrapper<T0>::template apply<V>(rhs)); |
| 403 | } |
| 404 | else |
| 405 | { |
| 406 | return binary_dispatcher_lhs<R, T0, Types...>::apply(std::forward<V>(lhs), |
| 407 | std::forward<V>(rhs), |
| 408 | std::forward<F>(f)); |
| 409 | } |
| 410 | } |
| 411 | }; |
| 412 | |
| 413 | template <typename R, typename T0, typename T1> |
| 414 | struct binary_dispatcher_lhs<R, T0, T1> |
| 415 | { |
| 416 | template <typename V, typename F> |
| 417 | VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f) |
| 418 | { |
| 419 | return std::forward<F>(f)(unwrapper<T1>::template apply<V>(lhs), |
| 420 | unwrapper<T0>::template apply<V>(rhs)); |
| 421 | } |
| 422 | }; |
| 423 | |
| 424 | template <typename R, typename... Types> |
| 425 | struct binary_dispatcher; |
| 426 | |
| 427 | template <typename R, typename T, typename... Types> |
| 428 | struct binary_dispatcher<R, T, Types...> |
| 429 | { |
| 430 | template <typename V, typename F> |
| 431 | VARIANT_INLINE static R apply(V&& v0, V&& v1, F&& f) |
| 432 | { |
| 433 | if (v0.template is<T>()) |
| 434 | { |
| 435 | if (v1.template is<T>()) |
| 436 | { |
| 437 | return std::forward<F>(f)(unwrapper<T>::template apply<V>(v0), |
| 438 | unwrapper<T>::template apply<V>(v1)); // call binary functor |
| 439 | } |
| 440 | else |
| 441 | { |
| 442 | return binary_dispatcher_rhs<R, T, Types...>::apply(std::forward<V>(v0), |
| 443 | std::forward<V>(v1), |
| 444 | std::forward<F>(f)); |
| 445 | } |
| 446 | } |
| 447 | else if (v1.template is<T>()) |
| 448 | { |
| 449 | return binary_dispatcher_lhs<R, T, Types...>::apply(std::forward<V>(v0), |
| 450 | std::forward<V>(v1), |
| 451 | std::forward<F>(f)); |
| 452 | } |
| 453 | return binary_dispatcher<R, Types...>::apply(std::forward<V>(v0), |
| 454 | std::forward<V>(v1), |
| 455 | std::forward<F>(f)); |
| 456 | } |
| 457 | }; |
| 458 | |
| 459 | template <typename R, typename T> |
| 460 | struct binary_dispatcher<R, T> |
| 461 | { |
| 462 | template <typename V, typename F> |
| 463 | VARIANT_INLINE static R apply(V&& v0, V&& v1, F&& f) |
| 464 | { |
| 465 | return std::forward<F>(f)(unwrapper<T>::template apply<V>(v0), |
| 466 | unwrapper<T>::template apply<V>(v1)); // call binary functor |
| 467 | } |
| 468 | }; |
| 469 | |
| 470 | // comparator functors |
| 471 | struct equal_comp |
| 472 | { |
| 473 | template <typename T> |
| 474 | bool operator()(T const& lhs, T const& rhs) const |
| 475 | { |
| 476 | return lhs == rhs; |
| 477 | } |
| 478 | }; |
| 479 | |
| 480 | struct less_comp |
| 481 | { |
| 482 | template <typename T> |
| 483 | bool operator()(T const& lhs, T const& rhs) const |
| 484 | { |
| 485 | return lhs < rhs; |
| 486 | } |
| 487 | }; |
| 488 | |
| 489 | template <typename Variant, typename Comp> |
| 490 | class comparer |
| 491 | { |
| 492 | public: |
| 493 | explicit comparer(Variant const& lhs) noexcept |
| 494 | : lhs_(lhs) {} |
| 495 | comparer& operator=(comparer const&) = delete; |
| 496 | // visitor |
| 497 | template <typename T> |
| 498 | bool operator()(T const& rhs_content) const |
| 499 | { |
| 500 | T const& lhs_content = lhs_.template get_unchecked<T>(); |
| 501 | return Comp()(lhs_content, rhs_content); |
| 502 | } |
| 503 | |
| 504 | private: |
| 505 | Variant const& lhs_; |
| 506 | }; |
| 507 | |
| 508 | // hashing visitor |
| 509 | struct hasher |
| 510 | { |
| 511 | template <typename T> |
| 512 | std::size_t operator()(const T& hashable) const |
| 513 | { |
| 514 | return std::hash<T>{}(hashable); |
| 515 | } |
| 516 | }; |
| 517 | |
| 518 | } // namespace detail |
| 519 | |
| 520 | struct no_init {}; |
| 521 | |
| 522 | template <typename... Types> |
| 523 | class variant |
| 524 | { |
| 525 | static_assert(sizeof...(Types) > 0, "Template parameter type list of variant can not be empty."); |
| 526 | static_assert(!detail::disjunction<std::is_reference<Types>...>::value, "Variant can not hold reference types. Maybe use std::reference_wrapper?"); |
| 527 | static_assert(!detail::disjunction<std::is_array<Types>...>::value, "Variant can not hold array types."); |
| 528 | static_assert(sizeof...(Types) < std::numeric_limits<type_index_t>::max(), "Internal index type must be able to accommodate all alternatives."); |
| 529 | private: |
| 530 | static const std::size_t data_size = detail::static_max<sizeof(Types)...>::value; |
| 531 | static const std::size_t data_align = detail::static_max<alignof(Types)...>::value; |
| 532 | public: |
| 533 | struct adapted_variant_tag; |
| 534 | using types = std::tuple<Types...>; |
| 535 | private: |
| 536 | using first_type = typename std::tuple_element<0, types>::type; |
| 537 | using unwrap_first_type = typename detail::unwrapper<first_type>::value_type; |
| 538 | using data_type = typename std::aligned_storage<data_size, data_align>::type; |
| 539 | using helper_type = detail::variant_helper<Types...>; |
| 540 | |
| 541 | template <typename V, typename T = unwrap_first_type> |
| 542 | using alternative_ref = typename detail::copy_cvref<V, T>::type; |
| 543 | |
| 544 | type_index_t type_index; |
| 545 | #ifdef __clang_analyzer__ |
| 546 | data_type data {}; |
| 547 | #else |
| 548 | data_type data; |
| 549 | #endif |
| 550 | |
| 551 | public: |
| 552 | VARIANT_INLINE variant() noexcept(std::is_nothrow_default_constructible<first_type>::value) |
| 553 | : type_index(sizeof...(Types)-1) |
| 554 | { |
| 555 | static_assert(std::is_default_constructible<first_type>::value, "First type in variant must be default constructible to allow default construction of variant."); |
| 556 | new (&data) first_type(); |
| 557 | } |
| 558 | |
| 559 | VARIANT_INLINE variant(no_init) noexcept |
| 560 | : type_index(detail::invalid_value) {} |
| 561 | |
| 562 | // http://isocpp.org/blog/2012/11/universal-references-in-c11-scott-meyers |
| 563 | template <typename T, typename Traits = detail::value_traits<T, Types...>, |
| 564 | typename Enable = typename std::enable_if<Traits::is_valid && !std::is_same<variant<Types...>, typename Traits::value_type>::value>::type > |
| 565 | VARIANT_INLINE variant(T&& val) noexcept(std::is_nothrow_constructible<typename Traits::target_type, T&&>::value) |
| 566 | : type_index(Traits::index) |
| 567 | { |
| 568 | new (&data) typename Traits::target_type(std::forward<T>(val)); |
| 569 | } |
| 570 | |
| 571 | VARIANT_INLINE variant(variant<Types...> const& old) |
| 572 | : type_index(old.type_index) |
| 573 | { |
| 574 | helper_type::copy(old.type_index, &old.data, &data); |
| 575 | } |
| 576 | |
| 577 | VARIANT_INLINE variant(variant<Types...>&& old) |
| 578 | noexcept(detail::conjunction<std::is_nothrow_move_constructible<Types>...>::value) |
| 579 | : type_index(old.type_index) |
| 580 | { |
| 581 | helper_type::move(old.type_index, &old.data, &data); |
| 582 | } |
| 583 | |
| 584 | private: |
| 585 | VARIANT_INLINE void copy_assign(variant<Types...> const& rhs) |
| 586 | { |
| 587 | helper_type::destroy(type_index, &data); |
| 588 | type_index = detail::invalid_value; |
| 589 | helper_type::copy(rhs.type_index, &rhs.data, &data); |
| 590 | type_index = rhs.type_index; |
| 591 | } |
| 592 | |
| 593 | VARIANT_INLINE void move_assign(variant<Types...>&& rhs) |
| 594 | { |
| 595 | helper_type::destroy(type_index, &data); |
| 596 | type_index = detail::invalid_value; |
| 597 | helper_type::move(rhs.type_index, &rhs.data, &data); |
| 598 | type_index = rhs.type_index; |
| 599 | } |
| 600 | |
| 601 | public: |
| 602 | VARIANT_INLINE variant<Types...>& operator=(variant<Types...>&& other) |
| 603 | // note we check for nothrow-constructible, not nothrow-assignable, since |
| 604 | // move_assign uses move-construction via placement new. |
| 605 | noexcept(detail::conjunction<std::is_nothrow_move_constructible<Types>...>::value) |
| 606 | { |
| 607 | if (this == &other) { // playing safe in release mode, hit assertion in debug. |
| 608 | assert(false); |
| 609 | return *this; |
| 610 | } |
| 611 | move_assign(std::move(other)); |
| 612 | return *this; |
| 613 | } |
| 614 | |
| 615 | VARIANT_INLINE variant<Types...>& operator=(variant<Types...> const& other) |
| 616 | { |
| 617 | if (this != &other) |
| 618 | copy_assign(other); |
| 619 | return *this; |
| 620 | } |
| 621 | |
| 622 | // conversions |
| 623 | // move-assign |
| 624 | template <typename T, typename Traits = detail::value_traits<T, Types...>, |
| 625 | typename Enable = typename std::enable_if<Traits::is_valid && !std::is_same<variant<Types...>, typename Traits::value_type>::value>::type > |
| 626 | VARIANT_INLINE variant<Types...>& operator=(T&& rhs) |
| 627 | // not that we check is_nothrow_constructible<T>, not is_nothrow_move_assignable<T>, |
| 628 | // since we construct a temporary |
| 629 | noexcept(std::is_nothrow_constructible<typename Traits::target_type, T&&>::value |
| 630 | && std::is_nothrow_move_assignable<variant<Types...>>::value) |
| 631 | { |
| 632 | variant<Types...> temp(std::forward<T>(rhs)); |
| 633 | move_assign(std::move(temp)); |
| 634 | return *this; |
| 635 | } |
| 636 | |
| 637 | // copy-assign |
| 638 | template <typename T> |
| 639 | VARIANT_INLINE variant<Types...>& operator=(T const& rhs) |
| 640 | { |
| 641 | variant<Types...> temp(rhs); |
| 642 | copy_assign(temp); |
| 643 | return *this; |
| 644 | } |
| 645 | |
| 646 | template <typename T, typename std::enable_if< |
| 647 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 648 | VARIANT_INLINE bool is() const |
| 649 | { |
| 650 | return type_index == detail::direct_type<T, Types...>::index; |
| 651 | } |
| 652 | |
| 653 | template <typename T,typename std::enable_if< |
| 654 | (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 655 | VARIANT_INLINE bool is() const |
| 656 | { |
| 657 | return type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index; |
| 658 | } |
| 659 | |
| 660 | VARIANT_INLINE bool valid() const |
| 661 | { |
| 662 | return type_index != detail::invalid_value; |
| 663 | } |
| 664 | |
| 665 | template <typename T, typename... Args> |
| 666 | VARIANT_INLINE void set(Args&&... args) |
| 667 | { |
| 668 | helper_type::destroy(type_index, &data); |
| 669 | type_index = detail::invalid_value; |
| 670 | new (&data) T(std::forward<Args>(args)...); |
| 671 | type_index = detail::direct_type<T, Types...>::index; |
| 672 | } |
| 673 | |
| 674 | // get_unchecked<T>() |
| 675 | template <typename T, typename std::enable_if< |
| 676 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 677 | VARIANT_INLINE T& get_unchecked() |
| 678 | { |
| 679 | return *reinterpret_cast<T*>(&data); |
| 680 | } |
| 681 | |
| 682 | #ifdef HAS_EXCEPTIONS |
| 683 | // get<T>() |
| 684 | template <typename T, typename std::enable_if< |
| 685 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 686 | VARIANT_INLINE T& get() |
| 687 | { |
| 688 | if (type_index == detail::direct_type<T, Types...>::index) |
| 689 | { |
| 690 | return *reinterpret_cast<T*>(&data); |
| 691 | } |
| 692 | else |
| 693 | { |
| 694 | throw bad_variant_access("in get<T>()"); |
| 695 | } |
| 696 | } |
| 697 | #endif |
| 698 | |
| 699 | template <typename T, typename std::enable_if< |
| 700 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 701 | VARIANT_INLINE T const& get_unchecked() const |
| 702 | { |
| 703 | return *reinterpret_cast<T const*>(&data); |
| 704 | } |
| 705 | |
| 706 | #ifdef HAS_EXCEPTIONS |
| 707 | template <typename T, typename std::enable_if< |
| 708 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 709 | VARIANT_INLINE T const& get() const |
| 710 | { |
| 711 | if (type_index == detail::direct_type<T, Types...>::index) |
| 712 | { |
| 713 | return *reinterpret_cast<T const*>(&data); |
| 714 | } |
| 715 | else |
| 716 | { |
| 717 | throw bad_variant_access("in get<T>()"); |
| 718 | } |
| 719 | } |
| 720 | #endif |
| 721 | |
| 722 | // get_unchecked<T>() - T stored as recursive_wrapper<T> |
| 723 | template <typename T, typename std::enable_if< |
| 724 | (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 725 | VARIANT_INLINE T& get_unchecked() |
| 726 | { |
| 727 | return (*reinterpret_cast<recursive_wrapper<T>*>(&data)).get(); |
| 728 | } |
| 729 | |
| 730 | #ifdef HAS_EXCEPTIONS |
| 731 | // get<T>() - T stored as recursive_wrapper<T> |
| 732 | template <typename T, typename std::enable_if< |
| 733 | (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 734 | VARIANT_INLINE T& get() |
| 735 | { |
| 736 | if (type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index) |
| 737 | { |
| 738 | return (*reinterpret_cast<recursive_wrapper<T>*>(&data)).get(); |
| 739 | } |
| 740 | else |
| 741 | { |
| 742 | throw bad_variant_access("in get<T>()"); |
| 743 | } |
| 744 | } |
| 745 | #endif |
| 746 | |
| 747 | template <typename T, typename std::enable_if< |
| 748 | (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 749 | VARIANT_INLINE T const& get_unchecked() const |
| 750 | { |
| 751 | return (*reinterpret_cast<recursive_wrapper<T> const*>(&data)).get(); |
| 752 | } |
| 753 | |
| 754 | #ifdef HAS_EXCEPTIONS |
| 755 | template <typename T, typename std::enable_if< |
| 756 | (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 757 | VARIANT_INLINE T const& get() const |
| 758 | { |
| 759 | if (type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index) |
| 760 | { |
| 761 | return (*reinterpret_cast<recursive_wrapper<T> const*>(&data)).get(); |
| 762 | } |
| 763 | else |
| 764 | { |
| 765 | throw bad_variant_access("in get<T>()"); |
| 766 | } |
| 767 | } |
| 768 | #endif |
| 769 | |
| 770 | // get_unchecked<T>() - T stored as std::reference_wrapper<T> |
| 771 | template <typename T, typename std::enable_if< |
| 772 | (detail::direct_type<std::reference_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 773 | VARIANT_INLINE T& get_unchecked() |
| 774 | { |
| 775 | return (*reinterpret_cast<std::reference_wrapper<T>*>(&data)).get(); |
| 776 | } |
| 777 | |
| 778 | #ifdef HAS_EXCEPTIONS |
| 779 | // get<T>() - T stored as std::reference_wrapper<T> |
| 780 | template <typename T, typename std::enable_if< |
| 781 | (detail::direct_type<std::reference_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 782 | VARIANT_INLINE T& get() |
| 783 | { |
| 784 | if (type_index == detail::direct_type<std::reference_wrapper<T>, Types...>::index) |
| 785 | { |
| 786 | return (*reinterpret_cast<std::reference_wrapper<T>*>(&data)).get(); |
| 787 | } |
| 788 | else |
| 789 | { |
| 790 | throw bad_variant_access("in get<T>()"); |
| 791 | } |
| 792 | } |
| 793 | #endif |
| 794 | |
| 795 | template <typename T, typename std::enable_if< |
| 796 | (detail::direct_type<std::reference_wrapper<T const>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 797 | VARIANT_INLINE T const& get_unchecked() const |
| 798 | { |
| 799 | return (*reinterpret_cast<std::reference_wrapper<T const> const*>(&data)).get(); |
| 800 | } |
| 801 | |
| 802 | #ifdef HAS_EXCEPTIONS |
| 803 | template <typename T, typename std::enable_if< |
| 804 | (detail::direct_type<std::reference_wrapper<T const>, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 805 | VARIANT_INLINE T const& get() const |
| 806 | { |
| 807 | if (type_index == detail::direct_type<std::reference_wrapper<T const>, Types...>::index) |
| 808 | { |
| 809 | return (*reinterpret_cast<std::reference_wrapper<T const> const*>(&data)).get(); |
| 810 | } |
| 811 | else |
| 812 | { |
| 813 | throw bad_variant_access("in get<T>()"); |
| 814 | } |
| 815 | } |
| 816 | #endif |
| 817 | |
| 818 | // This function is deprecated because it returns an internal index field. |
| 819 | // Use which() instead. |
| 820 | MAPBOX_VARIANT_DEPRECATED VARIANT_INLINE type_index_t get_type_index() const |
| 821 | { |
| 822 | return type_index; |
| 823 | } |
| 824 | |
| 825 | VARIANT_INLINE int which() const noexcept |
| 826 | { |
| 827 | return static_cast<int>(sizeof...(Types) - type_index - 1); |
| 828 | } |
| 829 | |
| 830 | template <typename T, typename std::enable_if< |
| 831 | (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> |
| 832 | VARIANT_INLINE static constexpr int which() noexcept |
| 833 | { |
| 834 | return static_cast<int>(sizeof...(Types)-detail::direct_type<T, Types...>::index - 1); |
| 835 | } |
| 836 | |
| 837 | // visitor |
| 838 | // unary |
| 839 | template <typename F, typename V, typename T0 = alternative_ref<V>, |
| 840 | typename R = detail::result_of_unary_visit<F, T0>> |
| 841 | VARIANT_INLINE static R visit(V&& v, F&& f) |
| 842 | { |
| 843 | return detail::dispatcher<R, Types...>::apply(std::forward<V>(v), std::forward<F>(f)); |
| 844 | } |
| 845 | |
| 846 | // binary |
| 847 | template <typename F, typename V, typename T0 = alternative_ref<V>, |
| 848 | typename R = detail::result_of_binary_visit<F, T0>> |
| 849 | VARIANT_INLINE static R binary_visit(V&& v0, V&& v1, F&& f) |
| 850 | { |
| 851 | return detail::binary_dispatcher<R, Types...>::apply(std::forward<V>(v0), |
| 852 | std::forward<V>(v1), |
| 853 | std::forward<F>(f)); |
| 854 | } |
| 855 | |
| 856 | // match |
| 857 | // unary |
| 858 | template <typename... Fs> |
| 859 | auto VARIANT_INLINE match(Fs&&... fs) const& |
| 860 | -> decltype(variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...))) |
| 861 | { |
| 862 | return variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)); |
| 863 | } |
| 864 | // non-const |
| 865 | template <typename... Fs> |
| 866 | auto VARIANT_INLINE match(Fs&&... fs) & |
| 867 | -> decltype(variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...))) |
| 868 | { |
| 869 | return variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)); |
| 870 | } |
| 871 | template <typename... Fs> |
| 872 | auto VARIANT_INLINE match(Fs&&... fs) && |
| 873 | -> decltype(variant::visit(std::move(*this), ::mapbox::util::make_visitor(std::forward<Fs>(fs)...))) |
| 874 | { |
| 875 | return variant::visit(std::move(*this), ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)); |
| 876 | } |
| 877 | |
| 878 | ~variant() noexcept // no-throw destructor |
| 879 | { |
| 880 | helper_type::destroy(type_index, &data); |
| 881 | } |
| 882 | |
| 883 | // comparison operators |
| 884 | // equality |
| 885 | VARIANT_INLINE bool operator==(variant const& rhs) const |
| 886 | { |
| 887 | assert(valid() && rhs.valid()); |
| 888 | if (this->which() != rhs.which()) |
| 889 | { |
| 890 | return false; |
| 891 | } |
| 892 | detail::comparer<variant, detail::equal_comp> visitor(*this); |
| 893 | return visit(rhs, visitor); |
| 894 | } |
| 895 | |
| 896 | VARIANT_INLINE bool operator!=(variant const& rhs) const |
| 897 | { |
| 898 | return !(*this == rhs); |
| 899 | } |
| 900 | |
| 901 | // less than |
| 902 | VARIANT_INLINE bool operator<(variant const& rhs) const |
| 903 | { |
| 904 | assert(valid() && rhs.valid()); |
| 905 | if (this->which() != rhs.which()) |
| 906 | { |
| 907 | return this->which() < rhs.which(); |
| 908 | } |
| 909 | detail::comparer<variant, detail::less_comp> visitor(*this); |
| 910 | return visit(rhs, visitor); |
| 911 | } |
| 912 | VARIANT_INLINE bool operator>(variant const& rhs) const |
| 913 | { |
| 914 | return rhs < *this; |
| 915 | } |
| 916 | VARIANT_INLINE bool operator<=(variant const& rhs) const |
| 917 | { |
| 918 | return !(*this > rhs); |
| 919 | } |
| 920 | VARIANT_INLINE bool operator>=(variant const& rhs) const |
| 921 | { |
| 922 | return !(*this < rhs); |
| 923 | } |
| 924 | }; |
| 925 | |
| 926 | // unary visitor interface |
| 927 | template <typename F, typename V> |
| 928 | auto VARIANT_INLINE apply_visitor(F&& f, V&& v) |
| 929 | -> decltype(v.visit(std::forward<V>(v), std::forward<F>(f))) |
| 930 | { |
| 931 | return v.visit(std::forward<V>(v), std::forward<F>(f)); |
| 932 | } |
| 933 | |
| 934 | // binary visitor interface |
| 935 | template <typename F, typename V> |
| 936 | auto VARIANT_INLINE apply_visitor(F&& f, V&& v0, V&& v1) |
| 937 | -> decltype(v0.binary_visit(std::forward<V>(v0), std::forward<V>(v1), std::forward<F>(f))) |
| 938 | { |
| 939 | return v0.binary_visit(std::forward<V>(v0), std::forward<V>(v1), std::forward<F>(f)); |
| 940 | } |
| 941 | |
| 942 | // getter interface |
| 943 | |
| 944 | #ifdef HAS_EXCEPTIONS |
| 945 | template <typename ResultType, typename T> |
| 946 | auto get(T& var)->decltype(var.template get<ResultType>()) |
| 947 | { |
| 948 | return var.template get<ResultType>(); |
| 949 | } |
| 950 | #endif |
| 951 | |
| 952 | template <typename ResultType, typename T> |
| 953 | ResultType& get_unchecked(T& var) |
| 954 | { |
| 955 | return var.template get_unchecked<ResultType>(); |
| 956 | } |
| 957 | |
| 958 | #ifdef HAS_EXCEPTIONS |
| 959 | template <typename ResultType, typename T> |
| 960 | auto get(T const& var)->decltype(var.template get<ResultType>()) |
| 961 | { |
| 962 | return var.template get<ResultType>(); |
| 963 | } |
| 964 | #endif |
| 965 | |
| 966 | template <typename ResultType, typename T> |
| 967 | ResultType const& get_unchecked(T const& var) |
| 968 | { |
| 969 | return var.template get_unchecked<ResultType>(); |
| 970 | } |
| 971 | // variant_size |
| 972 | template <typename T> |
| 973 | struct variant_size; |
| 974 | |
| 975 | //variable templates is c++14 |
| 976 | //template <typename T> |
| 977 | //constexpr std::size_t variant_size_v = variant_size<T>::value; |
| 978 | |
| 979 | template <typename T> |
| 980 | struct variant_size<const T> |
| 981 | : variant_size<T> {}; |
| 982 | |
| 983 | template <typename T> |
| 984 | struct variant_size<volatile T> |
| 985 | : variant_size<T> {}; |
| 986 | |
| 987 | template <typename T> |
| 988 | struct variant_size<const volatile T> |
| 989 | : variant_size<T> {}; |
| 990 | |
| 991 | template <typename... Types> |
| 992 | struct variant_size<variant<Types...>> |
| 993 | : std::integral_constant<std::size_t, sizeof...(Types)> {}; |
| 994 | |
| 995 | // variant_alternative |
| 996 | template <std::size_t Index, typename T> |
| 997 | struct variant_alternative; |
| 998 | |
| 999 | #if defined(__clang__) |
| 1000 | #if __has_builtin(__type_pack_element) |
| 1001 | #define has_type_pack_element |
| 1002 | #endif |
| 1003 | #endif |
| 1004 | |
| 1005 | #if defined(has_type_pack_element) |
| 1006 | template <std::size_t Index, typename ...Types> |
| 1007 | struct variant_alternative<Index, variant<Types...>> |
| 1008 | { |
| 1009 | static_assert(sizeof...(Types) > Index , "Index out of range"); |
| 1010 | using type = __type_pack_element<Index, Types...>; |
| 1011 | }; |
| 1012 | #else |
| 1013 | template <std::size_t Index, typename First, typename...Types> |
| 1014 | struct variant_alternative<Index, variant<First, Types...>> |
| 1015 | : variant_alternative<Index - 1, variant<Types...>> |
| 1016 | { |
| 1017 | static_assert(sizeof...(Types) > Index -1 , "Index out of range"); |
| 1018 | }; |
| 1019 | |
| 1020 | template <typename First, typename...Types> |
| 1021 | struct variant_alternative<0, variant<First, Types...>> |
| 1022 | { |
| 1023 | using type = First; |
| 1024 | }; |
| 1025 | |
| 1026 | #endif |
| 1027 | |
| 1028 | template <size_t Index, typename T> |
| 1029 | using variant_alternative_t = typename variant_alternative<Index, T>::type; |
| 1030 | |
| 1031 | template <size_t Index, typename T> |
| 1032 | struct variant_alternative<Index, const T> |
| 1033 | : std::add_const<variant_alternative<Index, T>> {}; |
| 1034 | |
| 1035 | template <size_t Index, typename T> |
| 1036 | struct variant_alternative<Index, volatile T> |
| 1037 | : std::add_volatile<variant_alternative<Index, T>> {}; |
| 1038 | |
| 1039 | template <size_t Index, typename T> |
| 1040 | struct variant_alternative<Index, const volatile T> |
| 1041 | : std::add_cv<variant_alternative<Index, T>> {}; |
| 1042 | |
| 1043 | } // namespace util |
| 1044 | } // namespace mapbox |
| 1045 | |
| 1046 | // hashable iff underlying types are hashable |
| 1047 | namespace std { |
| 1048 | template <typename... Types> |
| 1049 | struct hash< ::mapbox::util::variant<Types...>> { |
| 1050 | std::size_t operator()(const ::mapbox::util::variant<Types...>& v) const noexcept |
| 1051 | { |
| 1052 | return ::mapbox::util::apply_visitor(::mapbox::util::detail::hasher{}, v); |
| 1053 | } |
| 1054 | }; |
| 1055 | |
| 1056 | } |
| 1057 | |
| 1058 | #endif // MAPBOX_UTIL_VARIANT_HPP |