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 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 constexpr explicit(Extent != dynamic_extent) span(pointer ptr, size_type count); 60 constexpr explicit(Extent != dynamic_extent) span(pointer firstElem, pointer lastElem); 61 template <size_t N> 62 constexpr span(element_type (&arr)[N]) noexcept; 63 template <size_t N> 64 constexpr span(array<value_type, N>& arr) noexcept; 65 template <size_t N> 66 constexpr span(const array<value_type, N>& arr) noexcept; 67 template <class Container> 68 constexpr explicit(Extent != dynamic_extent) span(Container& cont); 69 template <class Container> 70 constexpr explicit(Extent != dynamic_extent) span(const Container& cont); 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 ~span() noexcept = default; 75 constexpr span& operator=(const span& other) noexcept = default; 76 77 // [span.sub], span subviews 78 template <size_t Count> 79 constexpr span<element_type, Count> first() const; 80 template <size_t Count> 81 constexpr span<element_type, Count> last() const; 82 template <size_t Offset, size_t Count = dynamic_extent> 83 constexpr span<element_type, see below> subspan() const; 84 85 constexpr span<element_type, dynamic_extent> first(size_type count) const; 86 constexpr span<element_type, dynamic_extent> last(size_type count) const; 87 constexpr span<element_type, dynamic_extent> subspan(size_type offset, size_type count = dynamic_extent) const; 88 89 // [span.obs], span observers 90 constexpr size_type size() const noexcept; 91 constexpr size_type size_bytes() const noexcept; 92 constexpr bool empty() const noexcept; 93 94 // [span.elem], span element access 95 constexpr reference operator[](size_type idx) const; 96 constexpr reference front() const; 97 constexpr reference back() const; 98 constexpr pointer data() const noexcept; 99 100 // [span.iterators], span iterator support 101 constexpr iterator begin() const noexcept; 102 constexpr iterator end() const noexcept; 103 constexpr reverse_iterator rbegin() const noexcept; 104 constexpr reverse_iterator rend() const noexcept; 105 106private: 107 pointer data_; // exposition only 108 size_type size_; // exposition only 109}; 110 111template<class T, size_t N> 112 span(T (&)[N]) -> span<T, N>; 113 114template<class T, size_t N> 115 span(array<T, N>&) -> span<T, N>; 116 117template<class T, size_t N> 118 span(const array<T, N>&) -> span<const T, N>; 119 120template<class Container> 121 span(Container&) -> span<typename Container::value_type>; 122 123template<class Container> 124 span(const Container&) -> span<const typename Container::value_type>; 125 126} // namespace std 127 128*/ 129 130#include <__config> 131#include <__debug> 132#include <__iterator/wrap_iter.h> 133#include <__ranges/enable_borrowed_range.h> 134#include <__ranges/enable_view.h> 135#include <array> // for array 136#include <cstddef> // for byte 137#include <iterator> // for iterators 138#include <limits> 139#include <type_traits> // for remove_cv, etc 140#include <version> 141 142#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 143#pragma GCC system_header 144#endif 145 146_LIBCPP_PUSH_MACROS 147#include <__undef_macros> 148 149_LIBCPP_BEGIN_NAMESPACE_STD 150 151#if _LIBCPP_STD_VER > 17 152 153inline constexpr size_t dynamic_extent = numeric_limits<size_t>::max(); 154template <typename _Tp, size_t _Extent = dynamic_extent> class span; 155 156 157template <class _Tp> 158struct __is_span_impl : public false_type {}; 159 160template <class _Tp, size_t _Extent> 161struct __is_span_impl<span<_Tp, _Extent>> : public true_type {}; 162 163template <class _Tp> 164struct __is_span : public __is_span_impl<remove_cv_t<_Tp>> {}; 165 166template <class _Tp> 167struct __is_std_array_impl : public false_type {}; 168 169template <class _Tp, size_t _Sz> 170struct __is_std_array_impl<array<_Tp, _Sz>> : public true_type {}; 171 172template <class _Tp> 173struct __is_std_array : public __is_std_array_impl<remove_cv_t<_Tp>> {}; 174 175template <class _Tp, class _ElementType, class = void> 176struct __is_span_compatible_container : public false_type {}; 177 178template <class _Tp, class _ElementType> 179struct __is_span_compatible_container<_Tp, _ElementType, 180 void_t< 181 // is not a specialization of span 182 typename enable_if<!__is_span<_Tp>::value, nullptr_t>::type, 183 // is not a specialization of array 184 typename enable_if<!__is_std_array<_Tp>::value, nullptr_t>::type, 185 // is_array_v<Container> is false, 186 typename enable_if<!is_array_v<_Tp>, nullptr_t>::type, 187 // data(cont) and size(cont) are well formed 188 decltype(data(declval<_Tp>())), 189 decltype(size(declval<_Tp>())), 190 // remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[] 191 typename enable_if< 192 is_convertible_v<remove_pointer_t<decltype(data(declval<_Tp &>()))>(*)[], 193 _ElementType(*)[]>, 194 nullptr_t>::type 195 >> 196 : public true_type {}; 197 198 199template <typename _Tp, size_t _Extent> 200class _LIBCPP_TEMPLATE_VIS span { 201public: 202// constants and types 203 using element_type = _Tp; 204 using value_type = remove_cv_t<_Tp>; 205 using size_type = size_t; 206 using difference_type = ptrdiff_t; 207 using pointer = _Tp *; 208 using const_pointer = const _Tp *; 209 using reference = _Tp &; 210 using const_reference = const _Tp &; 211#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS) 212 using iterator = pointer; 213#else 214 using iterator = __wrap_iter<pointer>; 215#endif 216 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 217 218 static constexpr size_type extent = _Extent; 219 220// [span.cons], span constructors, copy, assignment, and destructor 221 template <size_t _Sz = _Extent, enable_if_t<_Sz == 0, nullptr_t> = nullptr> 222 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr} {} 223 224 constexpr span (const span&) noexcept = default; 225 constexpr span& operator=(const span&) noexcept = default; 226 227 _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __ptr, size_type __count) : __data{__ptr} 228 { (void)__count; _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (ptr, len)"); } 229 _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __f, pointer __l) : __data{__f} 230 { (void)__l; _LIBCPP_ASSERT(_Extent == distance(__f, __l), "size mismatch in span's constructor (ptr, ptr)"); } 231 232 _LIBCPP_INLINE_VISIBILITY constexpr span(element_type (&__arr)[_Extent]) noexcept : __data{__arr} {} 233 234 template <class _OtherElementType, 235 enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 236 _LIBCPP_INLINE_VISIBILITY 237 constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {} 238 239 template <class _OtherElementType, 240 enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 241 _LIBCPP_INLINE_VISIBILITY 242 constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {} 243 244 template <class _Container> 245 _LIBCPP_INLINE_VISIBILITY 246 constexpr explicit span( _Container& __c, 247 enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr) 248 : __data{_VSTD::data(__c)} { 249 _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)"); 250 } 251 252 template <class _Container> 253 _LIBCPP_INLINE_VISIBILITY 254 constexpr explicit span(const _Container& __c, 255 enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr) 256 : __data{_VSTD::data(__c)} { 257 _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)"); 258 } 259 260 template <class _OtherElementType> 261 _LIBCPP_INLINE_VISIBILITY 262 constexpr span(const span<_OtherElementType, _Extent>& __other, 263 enable_if_t< 264 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 265 nullptr_t> = nullptr) 266 : __data{__other.data()} {} 267 268 template <class _OtherElementType> 269 _LIBCPP_INLINE_VISIBILITY 270 constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other, 271 enable_if_t< 272 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 273 nullptr_t> = nullptr) noexcept 274 : __data{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); } 275 276 277// ~span() noexcept = default; 278 279 template <size_t _Count> 280 _LIBCPP_INLINE_VISIBILITY 281 constexpr span<element_type, _Count> first() const noexcept 282 { 283 static_assert(_Count <= _Extent, "Count out of range in span::first()"); 284 return span<element_type, _Count>{data(), _Count}; 285 } 286 287 template <size_t _Count> 288 _LIBCPP_INLINE_VISIBILITY 289 constexpr span<element_type, _Count> last() const noexcept 290 { 291 static_assert(_Count <= _Extent, "Count out of range in span::last()"); 292 return span<element_type, _Count>{data() + size() - _Count, _Count}; 293 } 294 295 _LIBCPP_INLINE_VISIBILITY 296 constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept 297 { 298 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)"); 299 return {data(), __count}; 300 } 301 302 _LIBCPP_INLINE_VISIBILITY 303 constexpr span<element_type, dynamic_extent> last(size_type __count) const noexcept 304 { 305 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)"); 306 return {data() + size() - __count, __count}; 307 } 308 309 template <size_t _Offset, size_t _Count = dynamic_extent> 310 _LIBCPP_INLINE_VISIBILITY 311 constexpr auto subspan() const noexcept 312 -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset> 313 { 314 static_assert(_Offset <= _Extent, "Offset out of range in span::subspan()"); 315 static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset, "Offset + count out of range in span::subspan()"); 316 317 using _ReturnType = span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>; 318 return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 319 } 320 321 322 _LIBCPP_INLINE_VISIBILITY 323 constexpr span<element_type, dynamic_extent> 324 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept 325 { 326 _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)"); 327 _LIBCPP_ASSERT(__count <= size() || __count == dynamic_extent, "Count out of range in span::subspan(offset, count)"); 328 if (__count == dynamic_extent) 329 return {data() + __offset, size() - __offset}; 330 _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)"); 331 return {data() + __offset, __count}; 332 } 333 334 _LIBCPP_INLINE_VISIBILITY constexpr size_type size() const noexcept { return _Extent; } 335 _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return _Extent * sizeof(element_type); } 336 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return _Extent == 0; } 337 338 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept 339 { 340 _LIBCPP_ASSERT(__idx < size(), "span<T,N>[] index out of bounds"); 341 return __data[__idx]; 342 } 343 344 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 345 { 346 _LIBCPP_ASSERT(!empty(), "span<T, N>::front() on empty span"); 347 return __data[0]; 348 } 349 350 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 351 { 352 _LIBCPP_ASSERT(!empty(), "span<T, N>::back() on empty span"); 353 return __data[size()-1]; 354 } 355 356 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 357 358// [span.iter], span iterator support 359 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 360 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 361 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 362 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 363 364 _LIBCPP_INLINE_VISIBILITY span<const byte, _Extent * sizeof(element_type)> __as_bytes() const noexcept 365 { return span<const byte, _Extent * sizeof(element_type)>{reinterpret_cast<const byte *>(data()), size_bytes()}; } 366 367 _LIBCPP_INLINE_VISIBILITY span<byte, _Extent * sizeof(element_type)> __as_writable_bytes() const noexcept 368 { return span<byte, _Extent * sizeof(element_type)>{reinterpret_cast<byte *>(data()), size_bytes()}; } 369 370private: 371 pointer __data; 372 373}; 374 375 376template <typename _Tp> 377class _LIBCPP_TEMPLATE_VIS span<_Tp, dynamic_extent> { 378private: 379 380public: 381// constants and types 382 using element_type = _Tp; 383 using value_type = remove_cv_t<_Tp>; 384 using size_type = size_t; 385 using difference_type = ptrdiff_t; 386 using pointer = _Tp *; 387 using const_pointer = const _Tp *; 388 using reference = _Tp &; 389 using const_reference = const _Tp &; 390#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS) 391 using iterator = pointer; 392#else 393 using iterator = __wrap_iter<pointer>; 394#endif 395 using reverse_iterator = _VSTD::reverse_iterator<iterator>; 396 397 static constexpr size_type extent = dynamic_extent; 398 399// [span.cons], span constructors, copy, assignment, and destructor 400 _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr}, __size{0} {} 401 402 constexpr span (const span&) noexcept = default; 403 constexpr span& operator=(const span&) noexcept = default; 404 405 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __ptr, size_type __count) : __data{__ptr}, __size{__count} {} 406 _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __f, pointer __l) : __data{__f}, __size{static_cast<size_t>(distance(__f, __l))} {} 407 408 template <size_t _Sz> 409 _LIBCPP_INLINE_VISIBILITY 410 constexpr span(element_type (&__arr)[_Sz]) noexcept : __data{__arr}, __size{_Sz} {} 411 412 template <class _OtherElementType, size_t _Sz, 413 enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 414 _LIBCPP_INLINE_VISIBILITY 415 constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 416 417 template <class _OtherElementType, size_t _Sz, 418 enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr> 419 _LIBCPP_INLINE_VISIBILITY 420 constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {} 421 422 template <class _Container> 423 _LIBCPP_INLINE_VISIBILITY 424 constexpr span( _Container& __c, 425 enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr) 426 : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {} 427 428 template <class _Container> 429 _LIBCPP_INLINE_VISIBILITY 430 constexpr span(const _Container& __c, 431 enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr) 432 : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {} 433 434 435 template <class _OtherElementType, size_t _OtherExtent> 436 _LIBCPP_INLINE_VISIBILITY 437 constexpr span(const span<_OtherElementType, _OtherExtent>& __other, 438 enable_if_t< 439 is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, 440 nullptr_t> = nullptr) noexcept 441 : __data{__other.data()}, __size{__other.size()} {} 442 443// ~span() noexcept = default; 444 445 template <size_t _Count> 446 _LIBCPP_INLINE_VISIBILITY 447 constexpr span<element_type, _Count> first() const noexcept 448 { 449 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::first()"); 450 return span<element_type, _Count>{data(), _Count}; 451 } 452 453 template <size_t _Count> 454 _LIBCPP_INLINE_VISIBILITY 455 constexpr span<element_type, _Count> last() const noexcept 456 { 457 _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::last()"); 458 return span<element_type, _Count>{data() + size() - _Count, _Count}; 459 } 460 461 _LIBCPP_INLINE_VISIBILITY 462 constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept 463 { 464 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)"); 465 return {data(), __count}; 466 } 467 468 _LIBCPP_INLINE_VISIBILITY 469 constexpr span<element_type, dynamic_extent> last (size_type __count) const noexcept 470 { 471 _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)"); 472 return {data() + size() - __count, __count}; 473 } 474 475 template <size_t _Offset, size_t _Count = dynamic_extent> 476 _LIBCPP_INLINE_VISIBILITY 477 constexpr span<element_type, _Count> subspan() const noexcept 478 { 479 _LIBCPP_ASSERT(_Offset <= size(), "Offset out of range in span::subspan()"); 480 _LIBCPP_ASSERT(_Count == dynamic_extent || _Count <= size() - _Offset, "Offset + count out of range in span::subspan()"); 481 return span<element_type, _Count>{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; 482 } 483 484 constexpr span<element_type, dynamic_extent> 485 _LIBCPP_INLINE_VISIBILITY 486 subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept 487 { 488 _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)"); 489 _LIBCPP_ASSERT(__count <= size() || __count == dynamic_extent, "count out of range in span::subspan(offset, count)"); 490 if (__count == dynamic_extent) 491 return {data() + __offset, size() - __offset}; 492 _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)"); 493 return {data() + __offset, __count}; 494 } 495 496 _LIBCPP_INLINE_VISIBILITY constexpr size_type size() const noexcept { return __size; } 497 _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return __size * sizeof(element_type); } 498 _LIBCPP_INLINE_VISIBILITY constexpr bool empty() const noexcept { return __size == 0; } 499 500 _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept 501 { 502 _LIBCPP_ASSERT(__idx < size(), "span<T>[] index out of bounds"); 503 return __data[__idx]; 504 } 505 506 _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept 507 { 508 _LIBCPP_ASSERT(!empty(), "span<T>[].front() on empty span"); 509 return __data[0]; 510 } 511 512 _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept 513 { 514 _LIBCPP_ASSERT(!empty(), "span<T>[].back() on empty span"); 515 return __data[size()-1]; 516 } 517 518 519 _LIBCPP_INLINE_VISIBILITY constexpr pointer data() const noexcept { return __data; } 520 521// [span.iter], span iterator support 522 _LIBCPP_INLINE_VISIBILITY constexpr iterator begin() const noexcept { return iterator(data()); } 523 _LIBCPP_INLINE_VISIBILITY constexpr iterator end() const noexcept { return iterator(data() + size()); } 524 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rbegin() const noexcept { return reverse_iterator(end()); } 525 _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator rend() const noexcept { return reverse_iterator(begin()); } 526 527 _LIBCPP_INLINE_VISIBILITY span<const byte, dynamic_extent> __as_bytes() const noexcept 528 { return {reinterpret_cast<const byte *>(data()), size_bytes()}; } 529 530 _LIBCPP_INLINE_VISIBILITY span<byte, dynamic_extent> __as_writable_bytes() const noexcept 531 { return {reinterpret_cast<byte *>(data()), size_bytes()}; } 532 533private: 534 pointer __data; 535 size_type __size; 536}; 537 538#if !defined(_LIBCPP_HAS_NO_RANGES) 539template <class _Tp, size_t _Extent> 540inline constexpr bool ranges::enable_borrowed_range<span<_Tp, _Extent> > = true; 541 542template <class _ElementType, size_t _Extent> 543inline constexpr bool ranges::enable_view<span<_ElementType, _Extent>> = true; 544#endif // !defined(_LIBCPP_HAS_NO_RANGES) 545 546// as_bytes & as_writable_bytes 547template <class _Tp, size_t _Extent> 548_LIBCPP_INLINE_VISIBILITY 549auto as_bytes(span<_Tp, _Extent> __s) noexcept 550-> decltype(__s.__as_bytes()) 551{ return __s.__as_bytes(); } 552 553template <class _Tp, size_t _Extent> 554_LIBCPP_INLINE_VISIBILITY 555auto as_writable_bytes(span<_Tp, _Extent> __s) noexcept 556-> enable_if_t<!is_const_v<_Tp>, decltype(__s.__as_writable_bytes())> 557{ return __s.__as_writable_bytes(); } 558 559// Deduction guides 560template<class _Tp, size_t _Sz> 561 span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>; 562 563template<class _Tp, size_t _Sz> 564 span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>; 565 566template<class _Tp, size_t _Sz> 567 span(const array<_Tp, _Sz>&) -> span<const _Tp, _Sz>; 568 569template<class _Container> 570 span(_Container&) -> span<typename _Container::value_type>; 571 572template<class _Container> 573 span(const _Container&) -> span<const typename _Container::value_type>; 574 575#endif // _LIBCPP_STD_VER > 17 576 577_LIBCPP_END_NAMESPACE_STD 578 579_LIBCPP_POP_MACROS 580 581#endif // _LIBCPP_SPAN 582