1// -*- C++ -*- 2//===------------------------------ span ---------------------------------===// 3// 4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5// See https://llvm.org/LICENSE.txt for license information. 6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7// 8//===---------------------------------------------------------------------===// 9 10#ifndef _LIBCPP_SPAN 11#define _LIBCPP_SPAN 12 13/* 14 span synopsis 15 16namespace std { 17 18// constants 19inline constexpr ptrdiff_t dynamic_extent = -1; 20 21// [views.span], class template span 22template <class ElementType, ptrdiff_t Extent = dynamic_extent> 23 class span; 24 25// [span.objectrep], views of object representation 26template <class ElementType, ptrdiff_t Extent> 27 span<const byte, ((Extent == dynamic_extent) ? dynamic_extent : 28 (static_cast<ptrdiff_t>(sizeof(ElementType)) * Extent))> as_bytes(span<ElementType, Extent> s) noexcept; 29 30template <class ElementType, ptrdiff_t Extent> 31 span< byte, ((Extent == dynamic_extent) ? dynamic_extent : 32 (static_cast<ptrdiff_t>(sizeof(ElementType)) * Extent))> as_writable_bytes(span<ElementType, Extent> s) noexcept; 33 34 35namespace std { 36template <class ElementType, ptrdiff_t Extent = dynamic_extent> 37class span { 38public: 39 // constants and types 40 using element_type = ElementType; 41 using value_type = remove_cv_t<ElementType>; 42 using index_type = ptrdiff_t; 43 using difference_type = ptrdiff_t; 44 using pointer = element_type*; 45 using const_pointer = const element_type*; 46 using reference = element_type&; 47 using iterator = implementation-defined; 48 using const_reference = const element_type&; 49 using const_iterator = implementation-defined; 50 using reverse_iterator = std::reverse_iterator<iterator>; 51 using const_reverse_iterator = std::reverse_iterator<const_iterator>; 52 static constexpr index_type extent = Extent; 53 54 // [span.cons], span constructors, copy, assignment, and destructor 55 constexpr span() noexcept; 56 constexpr span(pointer ptr, index_type count); 57 constexpr span(pointer firstElem, pointer lastElem); 58 template <size_t N> 59 constexpr span(element_type (&arr)[N]) noexcept; 60 template <size_t N> 61 constexpr span(array<value_type, N>& arr) noexcept; 62 template <size_t N> 63 constexpr span(const array<value_type, N>& arr) noexcept; 64 template <class Container> 65 constexpr span(Container& cont); 66 template <class Container> 67 constexpr span(const Container& cont); 68 constexpr span(const span& other) noexcept = default; 69 template <class OtherElementType, ptrdiff_t OtherExtent> 70 constexpr span(const span<OtherElementType, OtherExtent>& s) noexcept; 71 ~span() noexcept = default; 72 constexpr span& operator=(const span& other) noexcept = default; 73 74 // [span.sub], span subviews 75 template <ptrdiff_t Count> 76 constexpr span<element_type, Count> first() const; 77 template <ptrdiff_t Count> 78 constexpr span<element_type, Count> last() const; 79 template <ptrdiff_t Offset, ptrdiff_t Count = dynamic_extent> 80 constexpr span<element_type, see below> subspan() const; 81 82 constexpr span<element_type, dynamic_extent> first(index_type count) const; 83 constexpr span<element_type, dynamic_extent> last(index_type count) const; 84 constexpr span<element_type, dynamic_extent> subspan(index_type offset, index_type count = dynamic_extent) const; 85 86 // [span.obs], span observers 87 constexpr index_type size() const noexcept; 88 constexpr index_type size_bytes() const noexcept; 89 constexpr bool empty() const noexcept; 90 91 // [span.elem], span element access 92 constexpr reference operator[](index_type idx) const; 93 constexpr reference front() const; 94 constexpr reference back() const; 95 constexpr pointer data() const noexcept; 96 97 // [span.iterators], span iterator support 98 constexpr iterator begin() const noexcept; 99 constexpr iterator end() const noexcept; 100 constexpr const_iterator cbegin() const noexcept; 101 constexpr const_iterator cend() const noexcept; 102 constexpr reverse_iterator rbegin() const noexcept; 103 constexpr reverse_iterator rend() const noexcept; 104 constexpr const_reverse_iterator crbegin() const noexcept; 105 constexpr const_reverse_iterator crend() const noexcept; 106 107private: 108 pointer data_; // exposition only 109 index_type size_; // exposition only 110}; 111 112template<class T, size_t N> 113 span(T (&)[N]) -> span<T, N>; 114 115template<class T, size_t N> 116 span(array<T, N>&) -> span<T, N>; 117 118template<class T, size_t N> 119 span(const array<T, N>&) -> span<const T, N>; 120 121template<class Container> 122 span(Container&) -> span<typename Container::value_type>; 123 124template<class Container> 125 span(const Container&) -> span<const typename Container::value_type>; 126 127} // namespace std 128 129*/ 130 131#include <__config> 132#include <cstddef> // for ptrdiff_t 133#include <iterator> // for iterators 134#include <array> // for array 135#include <type_traits> // for remove_cv, etc 136#include <cstddef> // for byte 137 138#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 139#pragma GCC system_header 140#endif 141 142_LIBCPP_BEGIN_NAMESPACE_STD 143 144#if _LIBCPP_STD_VER > 17 145 146inline constexpr ptrdiff_t dynamic_extent = -1; 147template <typename _Tp, ptrdiff_t _Extent = dynamic_extent> class span; 148 149 150template <class _Tp> 151struct __is_span_impl : public false_type {}; 152 153template <class _Tp, ptrdiff_t _Extent> 154struct __is_span_impl<span<_Tp, _Extent>> : public true_type {}; 155 156template <class _Tp> 157struct __is_span : public __is_span_impl<remove_cv_t<_Tp>> {}; 158 159template <class _Tp> 160struct __is_std_array_impl : public false_type {}; 161 162template <class _Tp, size_t _Sz> 163struct __is_std_array_impl<array<_Tp, _Sz>> : public true_type {}; 164 165template <class _Tp> 166struct __is_std_array : public __is_std_array_impl<remove_cv_t<_Tp>> {}; 167 168template <class _Tp, class _ElementType, class = void> 169struct __is_span_compatible_container : public false_type {}; 170 171template <class _Tp, class _ElementType> 172struct __is_span_compatible_container<_Tp, _ElementType, 173 void_t< 174 // is not a specialization of span 175 typename enable_if<!__is_span<_Tp>::value, nullptr_t>::type, 176 // is not a specialization of array 177 typename enable_if<!__is_std_array<_Tp>::value, nullptr_t>::type, 178 // is_array_v<Container> is false, 179 typename enable_if<!is_array_v<_Tp>, nullptr_t>::type, 180 // data(cont) and size(cont) are well formed 181 decltype(data(declval<_Tp>())), 182 decltype(size(declval<_Tp>())), 183 // remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[] 184 typename enable_if< 185 is_convertible_v<remove_pointer_t<decltype(data(declval<_Tp &>()))>(*)[], 186 _ElementType(*)[]>, 187 nullptr_t>::type 188 >> 189 : public true_type {}; 190 191 192template <typename _Tp, ptrdiff_t _Extent> 193class _LIBCPP_TEMPLATE_VIS span { 194public: 195// constants and types 196 using element_type = _Tp; 197 using value_type = remove_cv_t<_Tp>; 198 using index_type = ptrdiff_t; 199 using difference_type = ptrdiff_t; 200 using pointer = _Tp *; 201 using const_pointer = const _Tp *; 202 using reference = _Tp &; 203 using const_reference = const _Tp &; 204 using iterator = __wrap_iter<pointer>; 205 using const_iterator = __wrap_iter<const_pointer>; 206 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 207 using const_reverse_iterator = _VSTD::reverse_iterator<const_iterator>; 208 209 static constexpr index_type extent = _Extent; 210 static_assert (_Extent >= 0, "Can't have a span with an extent < 0"); 211 212// [span.cons], span constructors, copy, assignment, and destructor 213 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr} 214 { static_assert(_Extent == 0, "Can't default construct a statically sized span with size > 0"); } 215 216 constexpr span (const span&) noexcept = default; 217 constexpr span& operator=(const span&) noexcept = default; 218 219 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __ptr, index_type __count) : __data{__ptr} 220 { (void)__count; _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (ptr, len)"); } 221 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __f, pointer __l) : __data{__f} 222 { (void)__l; _LIBCPP_ASSERT(_Extent == distance(__f, __l), "size mismatch in span's constructor (ptr, ptr)"); } 223 224 _LIBCPP_INLINE_VISIBILITY constexpr span(element_type (&__arr)[_Extent]) noexcept : __data{__arr} {} 225 _LIBCPP_INLINE_VISIBILITY constexpr span( array<value_type, _Extent>& __arr) noexcept : __data{__arr.data()} {} 226 _LIBCPP_INLINE_VISIBILITY constexpr span(const array<value_type, _Extent>& __arr) noexcept : __data{__arr.data()} {} 227 228 template <class _OtherElementType> 229 inline _LIBCPP_INLINE_VISIBILITY 230 constexpr span(const span<_OtherElementType, _Extent>& __other, 231 enable_if_t< 232 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 233 nullptr_t> = nullptr) 234 : __data{__other.data()} {} 235 236 template <class _OtherElementType> 237 inline _LIBCPP_INLINE_VISIBILITY 238 constexpr span(const span<_OtherElementType, dynamic_extent>& __other, 239 enable_if_t< 240 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 241 nullptr_t> = nullptr) noexcept 242 : __data{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); } 243 244 245// ~span() noexcept = default; 246 247 template <ptrdiff_t _Count> 248 inline _LIBCPP_INLINE_VISIBILITY 249 constexpr span<element_type, _Count> first() const noexcept 250 { 251 static_assert(_Count >= 0, "Count must be >= 0 in span::first()"); 252 static_assert(_Count <= _Extent, "Count out of range in span::first()"); 253 return {data(), _Count}; 254 } 255 256 template <ptrdiff_t _Count> 257 inline _LIBCPP_INLINE_VISIBILITY 258 constexpr span<element_type, _Count> last() const noexcept 259 { 260 static_assert(_Count >= 0, "Count must be >= 0 in span::last()"); 261 static_assert(_Count <= _Extent, "Count out of range in span::last()"); 262 return {data() + size() - _Count, _Count}; 263 } 264 265 _LIBCPP_INLINE_VISIBILITY 266 constexpr span<element_type, dynamic_extent> first(index_type __count) const noexcept 267 { 268 _LIBCPP_ASSERT(__count >= 0 && __count <= size(), "Count out of range in span::first(count)"); 269 return {data(), __count}; 270 } 271 272 _LIBCPP_INLINE_VISIBILITY 273 constexpr span<element_type, dynamic_extent> last(index_type __count) const noexcept 274 { 275 _LIBCPP_ASSERT(__count >= 0 && __count <= size(), "Count out of range in span::last(count)"); 276 return {data() + size() - __count, __count}; 277 } 278 279 template <ptrdiff_t _Offset, ptrdiff_t _Count = dynamic_extent> 280 inline _LIBCPP_INLINE_VISIBILITY 281 constexpr auto subspan() const noexcept 282 -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset> 283 { 284 _LIBCPP_ASSERT(_Offset >= 0 && _Offset <= size(), "Offset out of range in span::subspan()"); 285 return {data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 286 } 287 288 289 inline _LIBCPP_INLINE_VISIBILITY 290 constexpr span<element_type, dynamic_extent> 291 subspan(index_type __offset, index_type __count = dynamic_extent) const noexcept 292 { 293 _LIBCPP_ASSERT( __offset >= 0 && __offset <= size(), "Offset out of range in span::subspan(offset, count)"); 294 _LIBCPP_ASSERT((__count >= 0 && __count <= size()) || __count == dynamic_extent, "Count out of range in span::subspan(offset, count)"); 295 if (__count == dynamic_extent) 296 return {data() + __offset, size() - __offset}; 297 _LIBCPP_ASSERT(__offset + __count <= size(), "count + offset out of range in span::subspan(offset, count)"); 298 return {data() + __offset, __count}; 299 } 300 301 _LIBCPP_INLINE_VISIBILITY constexpr index_type size() const noexcept { return _Extent; } 302 _LIBCPP_INLINE_VISIBILITY constexpr index_type size_bytes() const noexcept { return _Extent * sizeof(element_type); } 303 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return _Extent == 0; } 304 305 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](index_type __idx) const noexcept 306 { 307 _LIBCPP_ASSERT(__idx >= 0 && __idx < size(), "span<T,N>[] index out of bounds"); 308 return __data[__idx]; 309 } 310 311 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 312 { 313 static_assert(_Extent > 0, "span<T,N>[].front() on empty span"); 314 return __data[0]; 315 } 316 317 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 318 { 319 static_assert(_Extent > 0, "span<T,N>[].back() on empty span"); 320 return __data[size()-1]; 321 } 322 323 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 324 325// [span.iter], span iterator support 326 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 327 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 328 _LIBCPP_INLINE_VISIBILITY constexpr const_iterator cbegin() const noexcept { return const_iterator(data()); } 329 _LIBCPP_INLINE_VISIBILITY constexpr const_iterator cend() const noexcept { return const_iterator(data() + size()); } 330 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 331 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 332 _LIBCPP_INLINE_VISIBILITY constexpr const_reverse_iterator crbegin() const noexcept { return const_reverse_iterator(cend()); } 333 _LIBCPP_INLINE_VISIBILITY constexpr const_reverse_iterator crend() const noexcept { return const_reverse_iterator(cbegin()); } 334 335 _LIBCPP_INLINE_VISIBILITY constexpr void swap(span &__other) noexcept 336 { 337 pointer __p = __data; 338 __data = __other.__data; 339 __other.__data = __p; 340 } 341 342 _LIBCPP_INLINE_VISIBILITY span<const byte, _Extent * sizeof(element_type)> __as_bytes() const noexcept 343 { return {reinterpret_cast<const byte *>(data()), size_bytes()}; } 344 345 _LIBCPP_INLINE_VISIBILITY span<byte, _Extent * sizeof(element_type)> __as_writeable_bytes() const noexcept 346 { return {reinterpret_cast<byte *>(data()), size_bytes()}; } 347 348private: 349 pointer __data; 350 351}; 352 353 354template <typename _Tp> 355class _LIBCPP_TEMPLATE_VIS span<_Tp, dynamic_extent> { 356private: 357 358public: 359// constants and types 360 using element_type = _Tp; 361 using value_type = remove_cv_t<_Tp>; 362 using index_type = ptrdiff_t; 363 using difference_type = ptrdiff_t; 364 using pointer = _Tp *; 365 using const_pointer = const _Tp *; 366 using reference = _Tp &; 367 using const_reference = const _Tp &; 368 using iterator = __wrap_iter<pointer>; 369 using const_iterator = __wrap_iter<const_pointer>; 370 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 371 using const_reverse_iterator = _VSTD::reverse_iterator<const_iterator>; 372 373 static constexpr index_type extent = dynamic_extent; 374 375// [span.cons], span constructors, copy, assignment, and destructor 376 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr}, __size{0} {} 377 378 constexpr span (const span&) noexcept = default; 379 constexpr span& operator=(const span&) noexcept = default; 380 381 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __ptr, index_type __count) : __data{__ptr}, __size{__count} {} 382 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __f, pointer __l) : __data{__f}, __size{distance(__f, __l)} {} 383 384 template <size_t _Sz> 385 inline _LIBCPP_INLINE_VISIBILITY 386 constexpr span(element_type (&__arr)[_Sz]) noexcept : __data{__arr}, __size{_Sz} {} 387 388 template <size_t _Sz> 389 inline _LIBCPP_INLINE_VISIBILITY 390 constexpr span(array<value_type, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 391 392 template <size_t _Sz> 393 inline _LIBCPP_INLINE_VISIBILITY 394 constexpr span(const array<value_type, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 395 396 template <class _Container> 397 inline _LIBCPP_INLINE_VISIBILITY 398 constexpr span( _Container& __c, 399 enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr) 400 : __data{_VSTD::data(__c)}, __size{(index_type) _VSTD::size(__c)} {} 401 402 template <class _Container> 403 inline _LIBCPP_INLINE_VISIBILITY 404 constexpr span(const _Container& __c, 405 enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr) 406 : __data{_VSTD::data(__c)}, __size{(index_type) _VSTD::size(__c)} {} 407 408 409 template <class _OtherElementType, ptrdiff_t _OtherExtent> 410 inline _LIBCPP_INLINE_VISIBILITY 411 constexpr span(const span<_OtherElementType, _OtherExtent>& __other, 412 enable_if_t< 413 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 414 nullptr_t> = nullptr) noexcept 415 : __data{__other.data()}, __size{__other.size()} {} 416 417// ~span() noexcept = default; 418 419 template <ptrdiff_t _Count> 420 inline _LIBCPP_INLINE_VISIBILITY 421 constexpr span<element_type, _Count> first() const noexcept 422 { 423 static_assert(_Count >= 0, "Count must be >= 0 in span::first()"); 424 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::first()"); 425 return {data(), _Count}; 426 } 427 428 template <ptrdiff_t _Count> 429 inline _LIBCPP_INLINE_VISIBILITY 430 constexpr span<element_type, _Count> last() const noexcept 431 { 432 static_assert(_Count >= 0, "Count must be >= 0 in span::last()"); 433 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::last()"); 434 return {data() + size() - _Count, _Count}; 435 } 436 437 _LIBCPP_INLINE_VISIBILITY 438 constexpr span<element_type, dynamic_extent> first(index_type __count) const noexcept 439 { 440 _LIBCPP_ASSERT(__count >= 0 && __count <= size(), "Count out of range in span::first(count)"); 441 return {data(), __count}; 442 } 443 444 _LIBCPP_INLINE_VISIBILITY 445 constexpr span<element_type, dynamic_extent> last (index_type __count) const noexcept 446 { 447 _LIBCPP_ASSERT(__count >= 0 && __count <= size(), "Count out of range in span::last(count)"); 448 return {data() + size() - __count, __count}; 449 } 450 451 template <ptrdiff_t _Offset, ptrdiff_t _Count = dynamic_extent> 452 inline _LIBCPP_INLINE_VISIBILITY 453 constexpr span<_Tp, dynamic_extent> subspan() const noexcept 454 { 455 _LIBCPP_ASSERT(_Offset >= 0 && _Offset <= size(), "Offset out of range in span::subspan()"); 456 _LIBCPP_ASSERT(_Count == dynamic_extent || _Offset + _Count <= size(), "Count out of range in span::subspan()"); 457 return {data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 458 } 459 460 constexpr span<element_type, dynamic_extent> 461 inline _LIBCPP_INLINE_VISIBILITY 462 subspan(index_type __offset, index_type __count = dynamic_extent) const noexcept 463 { 464 _LIBCPP_ASSERT( __offset >= 0 && __offset <= size(), "Offset out of range in span::subspan(offset, count)"); 465 _LIBCPP_ASSERT((__count >= 0 && __count <= size()) || __count == dynamic_extent, "count out of range in span::subspan(offset, count)"); 466 if (__count == dynamic_extent) 467 return {data() + __offset, size() - __offset}; 468 _LIBCPP_ASSERT(__offset + __count <= size(), "Offset + count out of range in span::subspan(offset, count)"); 469 return {data() + __offset, __count}; 470 } 471 472 _LIBCPP_INLINE_VISIBILITY constexpr index_type size() const noexcept { return __size; } 473 _LIBCPP_INLINE_VISIBILITY constexpr index_type size_bytes() const noexcept { return __size * sizeof(element_type); } 474 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return __size == 0; } 475 476 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](index_type __idx) const noexcept 477 { 478 _LIBCPP_ASSERT(__idx >= 0 && __idx < size(), "span<T>[] index out of bounds"); 479 return __data[__idx]; 480 } 481 482 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 483 { 484 _LIBCPP_ASSERT(!empty(), "span<T>[].front() on empty span"); 485 return __data[0]; 486 } 487 488 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 489 { 490 _LIBCPP_ASSERT(!empty(), "span<T>[].back() on empty span"); 491 return __data[size()-1]; 492 } 493 494 495 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 496 497// [span.iter], span iterator support 498 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 499 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 500 _LIBCPP_INLINE_VISIBILITY constexpr const_iterator cbegin() const noexcept { return const_iterator(data()); } 501 _LIBCPP_INLINE_VISIBILITY constexpr const_iterator cend() const noexcept { return const_iterator(data() + size()); } 502 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 503 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 504 _LIBCPP_INLINE_VISIBILITY constexpr const_reverse_iterator crbegin() const noexcept { return const_reverse_iterator(cend()); } 505 _LIBCPP_INLINE_VISIBILITY constexpr const_reverse_iterator crend() const noexcept { return const_reverse_iterator(cbegin()); } 506 507 _LIBCPP_INLINE_VISIBILITY constexpr void swap(span &__other) noexcept 508 { 509 pointer __p = __data; 510 __data = __other.__data; 511 __other.__data = __p; 512 513 index_type __sz = __size; 514 __size = __other.__size; 515 __other.__size = __sz; 516 } 517 518 _LIBCPP_INLINE_VISIBILITY span<const byte, dynamic_extent> __as_bytes() const noexcept 519 { return {reinterpret_cast<const byte *>(data()), size_bytes()}; } 520 521 _LIBCPP_INLINE_VISIBILITY span<byte, dynamic_extent> __as_writeable_bytes() const noexcept 522 { return {reinterpret_cast<byte *>(data()), size_bytes()}; } 523 524private: 525 pointer __data; 526 index_type __size; 527}; 528 529// as_bytes & as_writeable_bytes 530template <class _Tp, ptrdiff_t _Extent> 531 auto as_bytes(span<_Tp, _Extent> __s) noexcept 532 -> decltype(__s.__as_bytes()) 533 { return __s.__as_bytes(); } 534 535template <class _Tp, ptrdiff_t _Extent> 536 auto as_writeable_bytes(span<_Tp, _Extent> __s) noexcept 537 -> typename enable_if<!is_const_v<_Tp>, decltype(__s.__as_writeable_bytes())>::type 538 { return __s.__as_writeable_bytes(); } 539 540template <class _Tp, ptrdiff_t _Extent> 541 constexpr void swap(span<_Tp, _Extent> &__lhs, span<_Tp, _Extent> &__rhs) noexcept 542 { __lhs.swap(__rhs); } 543 544 545// Deduction guides 546template<class _Tp, size_t _Sz> 547 span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>; 548 549template<class _Tp, size_t _Sz> 550 span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>; 551 552template<class _Tp, size_t _Sz> 553 span(const array<_Tp, _Sz>&) -> span<const _Tp, _Sz>; 554 555template<class _Container> 556 span(_Container&) -> span<typename _Container::value_type>; 557 558template<class _Container> 559 span(const _Container&) -> span<const typename _Container::value_type>; 560 561#endif // _LIBCPP_STD_VER > 17 562 563_LIBCPP_END_NAMESPACE_STD 564 565#endif // _LIBCPP_SPAN 566