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