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