1// -*- C++ -*- 2//===----------------------------------------------------------------------===// 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 size_t dynamic_extent = numeric_limits<size_t>::max(); 20 21// [views.span], class template span 22template <class ElementType, size_t Extent = dynamic_extent> 23 class span; 24 25template<class ElementType, size_t Extent> 26 inline constexpr bool ranges::enable_view<span<ElementType, Extent>> = true; 27 28template<class ElementType, size_t Extent> 29 inline constexpr bool ranges::enable_borrowed_range<span<ElementType, Extent>> = true; 30 31// [span.objectrep], views of object representation 32template <class ElementType, size_t Extent> 33 span<const byte, ((Extent == dynamic_extent) ? dynamic_extent : 34 (sizeof(ElementType) * Extent))> as_bytes(span<ElementType, Extent> s) noexcept; 35 36template <class ElementType, size_t Extent> 37 span< byte, ((Extent == dynamic_extent) ? dynamic_extent : 38 (sizeof(ElementType) * Extent))> as_writable_bytes(span<ElementType, Extent> s) noexcept; 39 40 41template <class ElementType, size_t Extent = dynamic_extent> 42class span { 43public: 44 // constants and types 45 using element_type = ElementType; 46 using value_type = remove_cv_t<ElementType>; 47 using size_type = size_t; 48 using difference_type = ptrdiff_t; 49 using pointer = element_type*; 50 using const_pointer = const element_type*; 51 using reference = element_type&; 52 using const_reference = const element_type&; 53 using iterator = implementation-defined; 54 using reverse_iterator = std::reverse_iterator<iterator>; 55 static constexpr size_type extent = Extent; 56 57 // [span.cons], span constructors, copy, assignment, and destructor 58 constexpr span() noexcept; 59 template <class It> 60 constexpr explicit(Extent != dynamic_extent) span(It first, size_type count); 61 template <class It, class End> 62 constexpr explicit(Extent != dynamic_extent) span(It first, End last); 63 template <size_t N> 64 constexpr span(type_identity_t<element_type> (&arr)[N]) noexcept; 65 template <size_t N> 66 constexpr span(array<value_type, N>& arr) noexcept; 67 template <size_t N> 68 constexpr span(const array<value_type, N>& arr) noexcept; 69 template<class R> 70 constexpr explicit(Extent != dynamic_extent) span(R&& r); 71 constexpr span(const span& other) noexcept = default; 72 template <class OtherElementType, size_t OtherExtent> 73 constexpr explicit(Extent != dynamic_extent) span(const span<OtherElementType, OtherExtent>& s) noexcept; 74 constexpr span& operator=(const span& other) noexcept = default; 75 76 // [span.sub], span subviews 77 template <size_t Count> 78 constexpr span<element_type, Count> first() const; 79 template <size_t Count> 80 constexpr span<element_type, Count> last() const; 81 template <size_t Offset, size_t Count = dynamic_extent> 82 constexpr span<element_type, see below> subspan() const; 83 84 constexpr span<element_type, dynamic_extent> first(size_type count) const; 85 constexpr span<element_type, dynamic_extent> last(size_type count) const; 86 constexpr span<element_type, dynamic_extent> subspan(size_type offset, size_type count = dynamic_extent) const; 87 88 // [span.obs], span observers 89 constexpr size_type size() const noexcept; 90 constexpr size_type size_bytes() const noexcept; 91 [[nodiscard]] constexpr bool empty() const noexcept; 92 93 // [span.elem], span element access 94 constexpr reference operator[](size_type idx) const; 95 constexpr reference front() const; 96 constexpr reference back() const; 97 constexpr pointer data() const noexcept; 98 99 // [span.iterators], span iterator support 100 constexpr iterator begin() const noexcept; 101 constexpr iterator end() const noexcept; 102 constexpr reverse_iterator rbegin() const noexcept; 103 constexpr reverse_iterator rend() const noexcept; 104 105private: 106 pointer data_; // exposition only 107 size_type size_; // exposition only 108}; 109 110template<class It, class EndOrSize> 111 span(It, EndOrSize) -> span<remove_reference_t<iter_reference_t<_It>>>; 112 113template<class T, size_t N> 114 span(T (&)[N]) -> span<T, N>; 115 116template<class T, size_t N> 117 span(array<T, N>&) -> span<T, N>; 118 119template<class T, size_t N> 120 span(const array<T, N>&) -> span<const T, N>; 121 122template<class R> 123 span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>; 124 125} // namespace std 126 127*/ 128 129#include <__assert> // all public C++ headers provide the assertion handler 130#include <__config> 131#include <__fwd/span.h> 132#include <__iterator/bounded_iter.h> 133#include <__iterator/concepts.h> 134#include <__iterator/iterator_traits.h> 135#include <__iterator/wrap_iter.h> 136#include <__memory/pointer_traits.h> 137#include <__ranges/concepts.h> 138#include <__ranges/data.h> 139#include <__ranges/enable_borrowed_range.h> 140#include <__ranges/enable_view.h> 141#include <__ranges/size.h> 142#include <__type_traits/is_convertible.h> 143#include <__type_traits/remove_cvref.h> 144#include <__type_traits/remove_reference.h> 145#include <__type_traits/type_identity.h> 146#include <__utility/forward.h> 147#include <array> // for array 148#include <cstddef> // for byte 149#include <version> 150 151// standard-mandated includes 152 153// [iterator.range] 154#include <__iterator/access.h> 155#include <__iterator/data.h> 156#include <__iterator/empty.h> 157#include <__iterator/reverse_access.h> 158#include <__iterator/size.h> 159 160#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 161# pragma GCC system_header 162#endif 163 164_LIBCPP_PUSH_MACROS 165#include <__undef_macros> 166 167_LIBCPP_BEGIN_NAMESPACE_STD 168 169#if _LIBCPP_STD_VER >= 20 170 171template <class _Tp> 172struct __is_std_array : false_type {}; 173 174template <class _Tp, size_t _Sz> 175struct __is_std_array<array<_Tp, _Sz>> : true_type {}; 176 177template <class _Tp> 178struct __is_std_span : false_type {}; 179 180template <class _Tp, size_t _Sz> 181struct __is_std_span<span<_Tp, _Sz>> : true_type {}; 182 183template <class _Range, class _ElementType> 184concept __span_compatible_range = 185 ranges::contiguous_range<_Range> && // 186 ranges::sized_range<_Range> && // 187 (ranges::borrowed_range<_Range> || is_const_v<_ElementType>)&& // 188 !__is_std_span<remove_cvref_t<_Range>>::value && // 189 !__is_std_array<remove_cvref_t<_Range>>::value && // 190 !is_array_v<remove_cvref_t<_Range>> && // 191 is_convertible_v<remove_reference_t<ranges::range_reference_t<_Range>> (*)[], _ElementType (*)[]>; 192 193template <class _From, class _To> 194concept __span_array_convertible = is_convertible_v<_From (*)[], _To (*)[]>; 195 196template <class _It, class _Tp> 197concept __span_compatible_iterator = 198 contiguous_iterator<_It> && __span_array_convertible<remove_reference_t<iter_reference_t<_It>>, _Tp>; 199 200template <class _Sentinel, class _It> 201concept __span_compatible_sentinel_for = sized_sentinel_for<_Sentinel, _It> && !is_convertible_v<_Sentinel, size_t>; 202 203template <typename _Tp, size_t _Extent> 204class _LIBCPP_TEMPLATE_VIS span { 205public: 206 // constants and types 207 using element_type = _Tp; 208 using value_type = remove_cv_t<_Tp>; 209 using size_type = size_t; 210 using difference_type = ptrdiff_t; 211 using pointer = _Tp*; 212 using const_pointer = const _Tp*; 213 using reference = _Tp&; 214 using const_reference = const _Tp&; 215# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 216 using iterator = __bounded_iter<pointer>; 217# else 218 using iterator = __wrap_iter<pointer>; 219# endif 220 using reverse_iterator = std::reverse_iterator<iterator>; 221 222 static constexpr size_type extent = _Extent; 223 224 // [span.cons], span constructors, copy, assignment, and destructor 225 template <size_t _Sz = _Extent> 226 requires(_Sz == 0) 227 _LIBCPP_HIDE_FROM_ABI constexpr span() noexcept : __data_{nullptr} {} 228 229 constexpr span(const span&) noexcept = default; 230 constexpr span& operator=(const span&) noexcept = default; 231 232 template <__span_compatible_iterator<element_type> _It> 233 _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_It __first, size_type __count) : __data_{std::to_address(__first)} { 234 (void)__count; 235 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Extent == __count, "size mismatch in span's constructor (iterator, len)"); 236 } 237 238 template <__span_compatible_iterator<element_type> _It, __span_compatible_sentinel_for<_It> _End> 239 _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_It __first, _End __last) : __data_{std::to_address(__first)} { 240 // [span.cons]/10 241 // Throws: When and what last - first throws. 242 [[maybe_unused]] auto __dist = __last - __first; 243 _LIBCPP_ASSERT_VALID_INPUT_RANGE(__dist >= 0, "invalid range in span's constructor (iterator, sentinel)"); 244 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( 245 __dist == _Extent, "invalid range in span's constructor (iterator, sentinel): last - first != extent"); 246 } 247 248 _LIBCPP_HIDE_FROM_ABI constexpr span(type_identity_t<element_type> (&__arr)[_Extent]) noexcept : __data_{__arr} {} 249 250 template <__span_array_convertible<element_type> _OtherElementType> 251 _LIBCPP_HIDE_FROM_ABI constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data_{__arr.data()} {} 252 253 template <class _OtherElementType> 254 requires __span_array_convertible<const _OtherElementType, element_type> 255 _LIBCPP_HIDE_FROM_ABI constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept 256 : __data_{__arr.data()} {} 257 258 template <__span_compatible_range<element_type> _Range> 259 _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_Range&& __r) : __data_{ranges::data(__r)} { 260 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(ranges::size(__r) == _Extent, "size mismatch in span's constructor (range)"); 261 } 262 263 template <__span_array_convertible<element_type> _OtherElementType> 264 _LIBCPP_HIDE_FROM_ABI constexpr span(const span<_OtherElementType, _Extent>& __other) : __data_{__other.data()} {} 265 266 template <__span_array_convertible<element_type> _OtherElementType> 267 _LIBCPP_HIDE_FROM_ABI constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other) noexcept 268 : __data_{__other.data()} { 269 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); 270 } 271 272 template <size_t _Count> 273 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, _Count> first() const noexcept { 274 static_assert(_Count <= _Extent, "span<T, N>::first<Count>(): Count out of range"); 275 return span<element_type, _Count>{data(), _Count}; 276 } 277 278 template <size_t _Count> 279 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, _Count> last() const noexcept { 280 static_assert(_Count <= _Extent, "span<T, N>::last<Count>(): Count out of range"); 281 return span<element_type, _Count>{data() + size() - _Count, _Count}; 282 } 283 284 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept { 285 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span<T, N>::first(count): count out of range"); 286 return {data(), __count}; 287 } 288 289 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, dynamic_extent> last(size_type __count) const noexcept { 290 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span<T, N>::last(count): count out of range"); 291 return {data() + size() - __count, __count}; 292 } 293 294 template <size_t _Offset, size_t _Count = dynamic_extent> 295 _LIBCPP_HIDE_FROM_ABI constexpr auto subspan() const noexcept 296 -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset> { 297 static_assert(_Offset <= _Extent, "span<T, N>::subspan<Offset, Count>(): Offset out of range"); 298 static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset, 299 "span<T, N>::subspan<Offset, Count>(): Offset + Count out of range"); 300 301 using _ReturnType = span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>; 302 return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 303 } 304 305 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, dynamic_extent> 306 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept { 307 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__offset <= size(), "span<T, N>::subspan(offset, count): offset out of range"); 308 if (__count == dynamic_extent) 309 return {data() + __offset, size() - __offset}; 310 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( 311 __count <= size() - __offset, "span<T, N>::subspan(offset, count): offset + count out of range"); 312 return {data() + __offset, __count}; 313 } 314 315 _LIBCPP_HIDE_FROM_ABI constexpr size_type size() const noexcept { return _Extent; } 316 _LIBCPP_HIDE_FROM_ABI constexpr size_type size_bytes() const noexcept { return _Extent * sizeof(element_type); } 317 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const noexcept { return _Extent == 0; } 318 319 _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](size_type __idx) const noexcept { 320 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__idx < size(), "span<T, N>::operator[](index): index out of range"); 321 return __data_[__idx]; 322 } 323 324 _LIBCPP_HIDE_FROM_ABI constexpr reference front() const noexcept { 325 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span<T, N>::front() on empty span"); 326 return __data_[0]; 327 } 328 329 _LIBCPP_HIDE_FROM_ABI constexpr reference back() const noexcept { 330 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span<T, N>::back() on empty span"); 331 return __data_[size() - 1]; 332 } 333 334 _LIBCPP_HIDE_FROM_ABI constexpr pointer data() const noexcept { return __data_; } 335 336 // [span.iter], span iterator support 337 _LIBCPP_HIDE_FROM_ABI constexpr iterator begin() const noexcept { 338# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 339 return std::__make_bounded_iter(data(), data(), data() + size()); 340# else 341 return iterator(data()); 342# endif 343 } 344 _LIBCPP_HIDE_FROM_ABI constexpr iterator end() const noexcept { 345# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 346 return std::__make_bounded_iter(data() + size(), data(), data() + size()); 347# else 348 return iterator(data() + size()); 349# endif 350 } 351 _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 352 _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 353 354 _LIBCPP_HIDE_FROM_ABI span<const byte, _Extent * sizeof(element_type)> __as_bytes() const noexcept { 355 return span<const byte, _Extent * sizeof(element_type)>{reinterpret_cast<const byte*>(data()), size_bytes()}; 356 } 357 358 _LIBCPP_HIDE_FROM_ABI span<byte, _Extent * sizeof(element_type)> __as_writable_bytes() const noexcept { 359 return span<byte, _Extent * sizeof(element_type)>{reinterpret_cast<byte*>(data()), size_bytes()}; 360 } 361 362private: 363 pointer __data_; 364}; 365 366template <typename _Tp> 367class _LIBCPP_TEMPLATE_VIS span<_Tp, dynamic_extent> { 368public: 369 // constants and types 370 using element_type = _Tp; 371 using value_type = remove_cv_t<_Tp>; 372 using size_type = size_t; 373 using difference_type = ptrdiff_t; 374 using pointer = _Tp*; 375 using const_pointer = const _Tp*; 376 using reference = _Tp&; 377 using const_reference = const _Tp&; 378# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 379 using iterator = __bounded_iter<pointer>; 380# else 381 using iterator = __wrap_iter<pointer>; 382# endif 383 using reverse_iterator = std::reverse_iterator<iterator>; 384 385 static constexpr size_type extent = dynamic_extent; 386 387 // [span.cons], span constructors, copy, assignment, and destructor 388 _LIBCPP_HIDE_FROM_ABI constexpr span() noexcept : __data_{nullptr}, __size_{0} {} 389 390 constexpr span(const span&) noexcept = default; 391 constexpr span& operator=(const span&) noexcept = default; 392 393 template <__span_compatible_iterator<element_type> _It> 394 _LIBCPP_HIDE_FROM_ABI constexpr span(_It __first, size_type __count) 395 : __data_{std::to_address(__first)}, __size_{__count} {} 396 397 template <__span_compatible_iterator<element_type> _It, __span_compatible_sentinel_for<_It> _End> 398 _LIBCPP_HIDE_FROM_ABI constexpr span(_It __first, _End __last) 399 : __data_(std::to_address(__first)), __size_(__last - __first) { 400 _LIBCPP_ASSERT_VALID_INPUT_RANGE(__last - __first >= 0, "invalid range in span's constructor (iterator, sentinel)"); 401 } 402 403 template <size_t _Sz> 404 _LIBCPP_HIDE_FROM_ABI constexpr span(type_identity_t<element_type> (&__arr)[_Sz]) noexcept 405 : __data_{__arr}, __size_{_Sz} {} 406 407 template <__span_array_convertible<element_type> _OtherElementType, size_t _Sz> 408 _LIBCPP_HIDE_FROM_ABI constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept 409 : __data_{__arr.data()}, __size_{_Sz} {} 410 411 template <class _OtherElementType, size_t _Sz> 412 requires __span_array_convertible<const _OtherElementType, element_type> 413 _LIBCPP_HIDE_FROM_ABI constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept 414 : __data_{__arr.data()}, __size_{_Sz} {} 415 416 template <__span_compatible_range<element_type> _Range> 417 _LIBCPP_HIDE_FROM_ABI constexpr span(_Range&& __r) : __data_(ranges::data(__r)), __size_{ranges::size(__r)} {} 418 419 template <__span_array_convertible<element_type> _OtherElementType, size_t _OtherExtent> 420 _LIBCPP_HIDE_FROM_ABI constexpr span(const span<_OtherElementType, _OtherExtent>& __other) noexcept 421 : __data_{__other.data()}, __size_{__other.size()} {} 422 423 template <size_t _Count> 424 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, _Count> first() const noexcept { 425 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count <= size(), "span<T>::first<Count>(): Count out of range"); 426 return span<element_type, _Count>{data(), _Count}; 427 } 428 429 template <size_t _Count> 430 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, _Count> last() const noexcept { 431 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count <= size(), "span<T>::last<Count>(): Count out of range"); 432 return span<element_type, _Count>{data() + size() - _Count, _Count}; 433 } 434 435 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept { 436 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span<T>::first(count): count out of range"); 437 return {data(), __count}; 438 } 439 440 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, dynamic_extent> last(size_type __count) const noexcept { 441 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span<T>::last(count): count out of range"); 442 return {data() + size() - __count, __count}; 443 } 444 445 template <size_t _Offset, size_t _Count = dynamic_extent> 446 _LIBCPP_HIDE_FROM_ABI constexpr span<element_type, _Count> subspan() const noexcept { 447 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Offset <= size(), "span<T>::subspan<Offset, Count>(): Offset out of range"); 448 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count == dynamic_extent || _Count <= size() - _Offset, 449 "span<T>::subspan<Offset, Count>(): Offset + Count out of range"); 450 return span<element_type, _Count>{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 451 } 452 453 constexpr span<element_type, dynamic_extent> _LIBCPP_HIDE_FROM_ABI 454 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept { 455 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__offset <= size(), "span<T>::subspan(offset, count): offset out of range"); 456 if (__count == dynamic_extent) 457 return {data() + __offset, size() - __offset}; 458 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( 459 __count <= size() - __offset, "span<T>::subspan(offset, count): offset + count out of range"); 460 return {data() + __offset, __count}; 461 } 462 463 _LIBCPP_HIDE_FROM_ABI constexpr size_type size() const noexcept { return __size_; } 464 _LIBCPP_HIDE_FROM_ABI constexpr size_type size_bytes() const noexcept { return __size_ * sizeof(element_type); } 465 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const noexcept { return __size_ == 0; } 466 467 _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](size_type __idx) const noexcept { 468 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__idx < size(), "span<T>::operator[](index): index out of range"); 469 return __data_[__idx]; 470 } 471 472 _LIBCPP_HIDE_FROM_ABI constexpr reference front() const noexcept { 473 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span<T>::front() on empty span"); 474 return __data_[0]; 475 } 476 477 _LIBCPP_HIDE_FROM_ABI constexpr reference back() const noexcept { 478 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span<T>::back() on empty span"); 479 return __data_[size() - 1]; 480 } 481 482 _LIBCPP_HIDE_FROM_ABI constexpr pointer data() const noexcept { return __data_; } 483 484 // [span.iter], span iterator support 485 _LIBCPP_HIDE_FROM_ABI constexpr iterator begin() const noexcept { 486# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 487 return std::__make_bounded_iter(data(), data(), data() + size()); 488# else 489 return iterator(data()); 490# endif 491 } 492 _LIBCPP_HIDE_FROM_ABI constexpr iterator end() const noexcept { 493# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS 494 return std::__make_bounded_iter(data() + size(), data(), data() + size()); 495# else 496 return iterator(data() + size()); 497# endif 498 } 499 _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 500 _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 501 502 _LIBCPP_HIDE_FROM_ABI span<const byte, dynamic_extent> __as_bytes() const noexcept { 503 return {reinterpret_cast<const byte*>(data()), size_bytes()}; 504 } 505 506 _LIBCPP_HIDE_FROM_ABI span<byte, dynamic_extent> __as_writable_bytes() const noexcept { 507 return {reinterpret_cast<byte*>(data()), size_bytes()}; 508 } 509 510private: 511 pointer __data_; 512 size_type __size_; 513}; 514 515template <class _Tp, size_t _Extent> 516inline constexpr bool ranges::enable_borrowed_range<span<_Tp, _Extent> > = true; 517 518template <class _ElementType, size_t _Extent> 519inline constexpr bool ranges::enable_view<span<_ElementType, _Extent>> = true; 520 521// as_bytes & as_writable_bytes 522template <class _Tp, size_t _Extent> 523_LIBCPP_HIDE_FROM_ABI auto as_bytes(span<_Tp, _Extent> __s) noexcept { 524 return __s.__as_bytes(); 525} 526 527template <class _Tp, size_t _Extent> 528 requires(!is_const_v<_Tp>) 529_LIBCPP_HIDE_FROM_ABI auto as_writable_bytes(span<_Tp, _Extent> __s) noexcept { 530 return __s.__as_writable_bytes(); 531} 532 533# if _LIBCPP_STD_VER >= 20 534template <contiguous_iterator _It, class _EndOrSize> 535span(_It, _EndOrSize) -> span<remove_reference_t<iter_reference_t<_It>>>; 536# endif // _LIBCPP_STD_VER >= 20 537 538template <class _Tp, size_t _Sz> 539span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>; 540 541template <class _Tp, size_t _Sz> 542span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>; 543 544template <class _Tp, size_t _Sz> 545span(const array<_Tp, _Sz>&) -> span<const _Tp, _Sz>; 546 547template <ranges::contiguous_range _Range> 548span(_Range&&) -> span<remove_reference_t<ranges::range_reference_t<_Range>>>; 549 550#endif // _LIBCPP_STD_VER >= 20 551 552_LIBCPP_END_NAMESPACE_STD 553 554_LIBCPP_POP_MACROS 555 556#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 557# include <concepts> 558# include <functional> 559# include <iterator> 560# include <type_traits> 561#endif 562 563#endif // _LIBCPP_SPAN 564