- tmp/tmpeppxrge3/{from.md → to.md} +29 -235
tmp/tmpeppxrge3/{from.md → to.md}
RENAMED
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@@ -1,8 +1,8 @@
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-
### Class template `span` <a id="views.span">[[views.span]]</a>
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#### Overview <a id="span.overview">[[span.overview]]</a>
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A `span` is a view over a contiguous sequence of objects, the storage of
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which is owned by some other object.
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All member functions of `span` have constant time complexity.
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@@ -20,11 +20,13 @@ namespace std {
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using pointer = element_type*;
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using const_pointer = const element_type*;
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using reference = element_type&;
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using const_reference = const element_type&;
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using iterator = implementation-defined // type of span::iterator; // see [span.iterators]
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using reverse_iterator = std::reverse_iterator<iterator>;
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static constexpr size_type extent = Extent;
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// [span.cons], constructors, copy, and assignment
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constexpr span() noexcept;
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template<class It>
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@@ -72,12 +74,16 @@ namespace std {
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constexpr pointer data() const noexcept;
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// [span.iterators], iterator support
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constexpr iterator begin() const noexcept;
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constexpr iterator end() const noexcept;
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constexpr reverse_iterator rbegin() const noexcept;
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constexpr reverse_iterator rend() const noexcept;
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private:
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pointer data_; // exposition only
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size_type size_; // exposition only
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};
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@@ -93,14 +99,17 @@ namespace std {
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template<class R>
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span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
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}
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```
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`ElementType` is required to be a complete object type that is not an
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abstract class type.
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#### Constructors, copy, and assignment <a id="span.cons">[[span.cons]]</a>
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``` cpp
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constexpr span() noexcept;
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```
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@@ -125,12 +134,12 @@ template<class It>
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- \[`first`, `first + count`) is a valid range.
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- `It` models `contiguous_iterator`.
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- If `extent` is not equal to `dynamic_extent`, then `count` is equal to
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`extent`.
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-
*Effects:* Initializes `data_` with `to_address(first)` and `size_`
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`count`.
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*Throws:* Nothing.
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``` cpp
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template<class It, class End>
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@@ -152,12 +161,12 @@ template<class It, class End>
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equal to `extent`.
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- \[`first`, `last`) is a valid range.
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- `It` models `contiguous_iterator`.
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- `End` models `sized_sentinel_for<It>`.
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*Effects:* Initializes `data_` with `to_address(first)` and `size_`
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`last - first`.
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*Throws:* When and what `last - first` throws.
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``` cpp
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template<size_t N> constexpr span(type_identity_t<element_type> (&arr)[N]) noexcept;
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@@ -202,12 +211,12 @@ template<class R> constexpr explicit(extent != dynamic_extent) span(R&& r);
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is equal to `extent`.
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- `R` models `ranges::contiguous_range` and `ranges::sized_range`.
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- If `is_const_v<element_type>` is `false`, `R` models
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`ranges::borrowed_range`.
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-
*Effects:* Initializes `data_` with `ranges::data(r)` and `size_`
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-
`ranges::size(r)`.
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| 210 |
*Throws:* What and when `ranges::data(r)` and `ranges::size(r)` throw.
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``` cpp
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constexpr span(const span& other) noexcept = default;
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@@ -247,11 +256,11 @@ extent != dynamic_extent && OtherExtent == dynamic_extent
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constexpr span& operator=(const span& other) noexcept = default;
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```
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| 250 |
*Ensures:* `size() == other.size() && data() == other.data()`.
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#### Deduction guides <a id="span.deduct">[[span.deduct]]</a>
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| 254 |
``` cpp
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template<class It, class EndOrSize>
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span(It, EndOrSize) -> span<remove_reference_t<iter_reference_t<It>>>;
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```
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@@ -263,11 +272,11 @@ template<class R>
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span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
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```
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| 265 |
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*Constraints:* `R` satisfies `ranges::contiguous_range`.
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#### Subviews <a id="span.sub">[[span.sub]]</a>
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| 269 |
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| 270 |
``` cpp
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template<size_t Count> constexpr span<element_type, Count> first() const;
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```
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@@ -358,17 +367,17 @@ is `true`.
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| 359 |
``` cpp
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| 360 |
return {data() + offset, count == dynamic_extent ? size() - offset : count};
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```
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| 362 |
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| 363 |
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#### Observers <a id="span.obs">[[span.obs]]</a>
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| 365 |
``` cpp
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| 366 |
constexpr size_type size() const noexcept;
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```
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| 368 |
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| 369 |
-
*Effects:* Equivalent to: `return size_;`
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| 370 |
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| 371 |
``` cpp
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| 372 |
constexpr size_type size_bytes() const noexcept;
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```
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@@ -378,11 +387,11 @@ constexpr size_type size_bytes() const noexcept;
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[[nodiscard]] constexpr bool empty() const noexcept;
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```
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*Effects:* Equivalent to: `return size() == 0;`
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| 382 |
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#### Element access <a id="span.elem">[[span.elem]]</a>
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| 385 |
``` cpp
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| 386 |
constexpr reference operator[](size_type idx) const;
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```
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| 388 |
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@@ -408,23 +417,25 @@ constexpr reference back() const;
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| 409 |
``` cpp
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| 410 |
constexpr pointer data() const noexcept;
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```
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| 412 |
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| 413 |
-
*Effects:* Equivalent to: `return data_;`
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| 415 |
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#### Iterator support <a id="span.iterators">[[span.iterators]]</a>
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| 417 |
``` cpp
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| 418 |
using iterator = implementation-defined // type of span::iterator;
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| 419 |
```
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| 420 |
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| 421 |
The type models `contiguous_iterator` [[iterator.concept.contiguous]],
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meets the *Cpp17RandomAccessIterator*
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requirements [[random.access.iterators]], and meets the requirements for
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constexpr iterators [[iterator.requirements.general]]
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-
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`span::iterator` as well.
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| 427 |
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| 428 |
``` cpp
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| 429 |
constexpr iterator begin() const noexcept;
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```
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@@ -448,222 +459,5 @@ constexpr reverse_iterator rbegin() const noexcept;
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constexpr reverse_iterator rend() const noexcept;
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```
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| 450 |
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| 451 |
*Effects:* Equivalent to: `return reverse_iterator(begin());`
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| 452 |
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| 453 |
-
#### Views of object representation <a id="span.objectrep">[[span.objectrep]]</a>
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| 454 |
-
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| 455 |
-
``` cpp
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| 456 |
-
template<class ElementType, size_t Extent>
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| 457 |
-
span<const byte, Extent == dynamic_extent ? dynamic_extent : sizeof(ElementType) * Extent>
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| 458 |
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as_bytes(span<ElementType, Extent> s) noexcept;
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| 459 |
-
```
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| 460 |
-
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| 461 |
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*Effects:* Equivalent to:
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| 462 |
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`return R{reinterpret_cast<const byte*>(s.data()), s.size_bytes()};`
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| 463 |
-
where `R` is the return type.
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| 464 |
-
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| 465 |
-
``` cpp
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| 466 |
-
template<class ElementType, size_t Extent>
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| 467 |
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span<byte, Extent == dynamic_extent ? dynamic_extent : sizeof(ElementType) * Extent>
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| 468 |
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as_writable_bytes(span<ElementType, Extent> s) noexcept;
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-
```
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| 470 |
-
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*Constraints:* `is_const_v<ElementType>` is `false`.
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| 472 |
-
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| 473 |
-
*Effects:* Equivalent to:
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`return R{reinterpret_cast<byte*>(s.data()), s.size_bytes()};` where `R`
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| 475 |
-
is the return type.
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| 476 |
-
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| 477 |
-
<!-- Link reference definitions -->
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| 478 |
-
[alg.sorting]: algorithms.md#alg.sorting
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| 479 |
-
[algorithm.stable]: library.md#algorithm.stable
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| 480 |
-
[algorithms]: algorithms.md#algorithms
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| 481 |
-
[algorithms.requirements]: algorithms.md#algorithms.requirements
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| 482 |
-
[allocator.requirements]: library.md#allocator.requirements
|
| 483 |
-
[allocator.requirements.completeness]: library.md#allocator.requirements.completeness
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| 484 |
-
[allocator.traits.members]: utilities.md#allocator.traits.members
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| 485 |
-
[array]: #array
|
| 486 |
-
[array.cons]: #array.cons
|
| 487 |
-
[array.creation]: #array.creation
|
| 488 |
-
[array.members]: #array.members
|
| 489 |
-
[array.overview]: #array.overview
|
| 490 |
-
[array.special]: #array.special
|
| 491 |
-
[array.syn]: #array.syn
|
| 492 |
-
[array.tuple]: #array.tuple
|
| 493 |
-
[array.zero]: #array.zero
|
| 494 |
-
[associative]: #associative
|
| 495 |
-
[associative.general]: #associative.general
|
| 496 |
-
[associative.map.syn]: #associative.map.syn
|
| 497 |
-
[associative.reqmts]: #associative.reqmts
|
| 498 |
-
[associative.reqmts.except]: #associative.reqmts.except
|
| 499 |
-
[associative.set.syn]: #associative.set.syn
|
| 500 |
-
[basic.string]: strings.md#basic.string
|
| 501 |
-
[class.copy.ctor]: class.md#class.copy.ctor
|
| 502 |
-
[class.default.ctor]: class.md#class.default.ctor
|
| 503 |
-
[class.dtor]: class.md#class.dtor
|
| 504 |
-
[container.adaptors]: #container.adaptors
|
| 505 |
-
[container.adaptors.general]: #container.adaptors.general
|
| 506 |
-
[container.alloc.req]: #container.alloc.req
|
| 507 |
-
[container.assoc.req]: #container.assoc.req
|
| 508 |
-
[container.hash.req]: #container.hash.req
|
| 509 |
-
[container.insert.return]: #container.insert.return
|
| 510 |
-
[container.node]: #container.node
|
| 511 |
-
[container.node.compat]: #container.node.compat
|
| 512 |
-
[container.node.cons]: #container.node.cons
|
| 513 |
-
[container.node.dtor]: #container.node.dtor
|
| 514 |
-
[container.node.modifiers]: #container.node.modifiers
|
| 515 |
-
[container.node.observers]: #container.node.observers
|
| 516 |
-
[container.node.overview]: #container.node.overview
|
| 517 |
-
[container.opt]: #container.opt
|
| 518 |
-
[container.req]: #container.req
|
| 519 |
-
[container.requirements]: #container.requirements
|
| 520 |
-
[container.requirements.dataraces]: #container.requirements.dataraces
|
| 521 |
-
[container.requirements.general]: #container.requirements.general
|
| 522 |
-
[container.rev.req]: #container.rev.req
|
| 523 |
-
[container.seq.opt]: #container.seq.opt
|
| 524 |
-
[container.seq.req]: #container.seq.req
|
| 525 |
-
[containers]: #containers
|
| 526 |
-
[containers.general]: #containers.general
|
| 527 |
-
[containers.summary]: #containers.summary
|
| 528 |
-
[dcl.init.aggr]: dcl.md#dcl.init.aggr
|
| 529 |
-
[deque]: #deque
|
| 530 |
-
[deque.capacity]: #deque.capacity
|
| 531 |
-
[deque.cons]: #deque.cons
|
| 532 |
-
[deque.erasure]: #deque.erasure
|
| 533 |
-
[deque.modifiers]: #deque.modifiers
|
| 534 |
-
[deque.overview]: #deque.overview
|
| 535 |
-
[deque.syn]: #deque.syn
|
| 536 |
-
[forward.list.erasure]: #forward.list.erasure
|
| 537 |
-
[forward.list.syn]: #forward.list.syn
|
| 538 |
-
[forwardlist]: #forwardlist
|
| 539 |
-
[forwardlist.access]: #forwardlist.access
|
| 540 |
-
[forwardlist.cons]: #forwardlist.cons
|
| 541 |
-
[forwardlist.iter]: #forwardlist.iter
|
| 542 |
-
[forwardlist.modifiers]: #forwardlist.modifiers
|
| 543 |
-
[forwardlist.ops]: #forwardlist.ops
|
| 544 |
-
[forwardlist.overview]: #forwardlist.overview
|
| 545 |
-
[hash.requirements]: library.md#hash.requirements
|
| 546 |
-
[iterator.concept.contiguous]: iterators.md#iterator.concept.contiguous
|
| 547 |
-
[iterator.requirements]: iterators.md#iterator.requirements
|
| 548 |
-
[iterator.requirements.general]: iterators.md#iterator.requirements.general
|
| 549 |
-
[list]: #list
|
| 550 |
-
[list.capacity]: #list.capacity
|
| 551 |
-
[list.cons]: #list.cons
|
| 552 |
-
[list.erasure]: #list.erasure
|
| 553 |
-
[list.modifiers]: #list.modifiers
|
| 554 |
-
[list.ops]: #list.ops
|
| 555 |
-
[list.overview]: #list.overview
|
| 556 |
-
[list.syn]: #list.syn
|
| 557 |
-
[map]: #map
|
| 558 |
-
[map.access]: #map.access
|
| 559 |
-
[map.cons]: #map.cons
|
| 560 |
-
[map.erasure]: #map.erasure
|
| 561 |
-
[map.modifiers]: #map.modifiers
|
| 562 |
-
[map.overview]: #map.overview
|
| 563 |
-
[multimap]: #multimap
|
| 564 |
-
[multimap.cons]: #multimap.cons
|
| 565 |
-
[multimap.erasure]: #multimap.erasure
|
| 566 |
-
[multimap.modifiers]: #multimap.modifiers
|
| 567 |
-
[multimap.overview]: #multimap.overview
|
| 568 |
-
[multiset]: #multiset
|
| 569 |
-
[multiset.cons]: #multiset.cons
|
| 570 |
-
[multiset.erasure]: #multiset.erasure
|
| 571 |
-
[multiset.overview]: #multiset.overview
|
| 572 |
-
[priority.queue]: #priority.queue
|
| 573 |
-
[priqueue.cons]: #priqueue.cons
|
| 574 |
-
[priqueue.cons.alloc]: #priqueue.cons.alloc
|
| 575 |
-
[priqueue.members]: #priqueue.members
|
| 576 |
-
[priqueue.overview]: #priqueue.overview
|
| 577 |
-
[priqueue.special]: #priqueue.special
|
| 578 |
-
[queue]: #queue
|
| 579 |
-
[queue.cons]: #queue.cons
|
| 580 |
-
[queue.cons.alloc]: #queue.cons.alloc
|
| 581 |
-
[queue.defn]: #queue.defn
|
| 582 |
-
[queue.ops]: #queue.ops
|
| 583 |
-
[queue.special]: #queue.special
|
| 584 |
-
[queue.syn]: #queue.syn
|
| 585 |
-
[random.access.iterators]: iterators.md#random.access.iterators
|
| 586 |
-
[res.on.data.races]: library.md#res.on.data.races
|
| 587 |
-
[sequence.reqmts]: #sequence.reqmts
|
| 588 |
-
[sequences]: #sequences
|
| 589 |
-
[sequences.general]: #sequences.general
|
| 590 |
-
[set]: #set
|
| 591 |
-
[set.cons]: #set.cons
|
| 592 |
-
[set.erasure]: #set.erasure
|
| 593 |
-
[set.overview]: #set.overview
|
| 594 |
-
[span.cons]: #span.cons
|
| 595 |
-
[span.deduct]: #span.deduct
|
| 596 |
-
[span.elem]: #span.elem
|
| 597 |
-
[span.iterators]: #span.iterators
|
| 598 |
-
[span.objectrep]: #span.objectrep
|
| 599 |
-
[span.obs]: #span.obs
|
| 600 |
-
[span.overview]: #span.overview
|
| 601 |
-
[span.sub]: #span.sub
|
| 602 |
-
[span.syn]: #span.syn
|
| 603 |
-
[stack]: #stack
|
| 604 |
-
[stack.cons]: #stack.cons
|
| 605 |
-
[stack.cons.alloc]: #stack.cons.alloc
|
| 606 |
-
[stack.defn]: #stack.defn
|
| 607 |
-
[stack.ops]: #stack.ops
|
| 608 |
-
[stack.special]: #stack.special
|
| 609 |
-
[stack.syn]: #stack.syn
|
| 610 |
-
[strings]: strings.md#strings
|
| 611 |
-
[swappable.requirements]: library.md#swappable.requirements
|
| 612 |
-
[tab:container.opt]: #tab:container.opt
|
| 613 |
-
[tab:container.req]: #tab:container.req
|
| 614 |
-
[tab:container.rev.req]: #tab:container.rev.req
|
| 615 |
-
[tab:container.seq.opt]: #tab:container.seq.opt
|
| 616 |
-
[tab:container.seq.req]: #tab:container.seq.req
|
| 617 |
-
[temp.deduct]: temp.md#temp.deduct
|
| 618 |
-
[temp.param]: temp.md#temp.param
|
| 619 |
-
[temp.type]: temp.md#temp.type
|
| 620 |
-
[unord]: #unord
|
| 621 |
-
[unord.general]: #unord.general
|
| 622 |
-
[unord.hash]: utilities.md#unord.hash
|
| 623 |
-
[unord.map]: #unord.map
|
| 624 |
-
[unord.map.cnstr]: #unord.map.cnstr
|
| 625 |
-
[unord.map.elem]: #unord.map.elem
|
| 626 |
-
[unord.map.erasure]: #unord.map.erasure
|
| 627 |
-
[unord.map.modifiers]: #unord.map.modifiers
|
| 628 |
-
[unord.map.overview]: #unord.map.overview
|
| 629 |
-
[unord.map.syn]: #unord.map.syn
|
| 630 |
-
[unord.multimap]: #unord.multimap
|
| 631 |
-
[unord.multimap.cnstr]: #unord.multimap.cnstr
|
| 632 |
-
[unord.multimap.erasure]: #unord.multimap.erasure
|
| 633 |
-
[unord.multimap.modifiers]: #unord.multimap.modifiers
|
| 634 |
-
[unord.multimap.overview]: #unord.multimap.overview
|
| 635 |
-
[unord.multiset]: #unord.multiset
|
| 636 |
-
[unord.multiset.cnstr]: #unord.multiset.cnstr
|
| 637 |
-
[unord.multiset.erasure]: #unord.multiset.erasure
|
| 638 |
-
[unord.multiset.overview]: #unord.multiset.overview
|
| 639 |
-
[unord.req]: #unord.req
|
| 640 |
-
[unord.req.except]: #unord.req.except
|
| 641 |
-
[unord.set]: #unord.set
|
| 642 |
-
[unord.set.cnstr]: #unord.set.cnstr
|
| 643 |
-
[unord.set.erasure]: #unord.set.erasure
|
| 644 |
-
[unord.set.overview]: #unord.set.overview
|
| 645 |
-
[unord.set.syn]: #unord.set.syn
|
| 646 |
-
[vector]: #vector
|
| 647 |
-
[vector.bool]: #vector.bool
|
| 648 |
-
[vector.capacity]: #vector.capacity
|
| 649 |
-
[vector.cons]: #vector.cons
|
| 650 |
-
[vector.data]: #vector.data
|
| 651 |
-
[vector.erasure]: #vector.erasure
|
| 652 |
-
[vector.modifiers]: #vector.modifiers
|
| 653 |
-
[vector.overview]: #vector.overview
|
| 654 |
-
[vector.syn]: #vector.syn
|
| 655 |
-
[views]: #views
|
| 656 |
-
[views.general]: #views.general
|
| 657 |
-
[views.span]: #views.span
|
| 658 |
-
|
| 659 |
-
[^1]: Equality comparison is a refinement of partitioning if no two
|
| 660 |
-
objects that compare equal fall into different partitions.
|
| 661 |
-
|
| 662 |
-
[^2]: These member functions are only provided by containers whose
|
| 663 |
-
iterators are random access iterators.
|
| 664 |
-
|
| 665 |
-
[^3]: As specified in [[allocator.requirements]], the requirements in
|
| 666 |
-
this Clause apply only to lists whose allocators compare equal.
|
| 667 |
-
|
| 668 |
-
[^4]: `reserve()` uses `Allocator::allocate()` which may throw an
|
| 669 |
-
appropriate exception.
|
|
|
|
| 1 |
+
#### Class template `span` <a id="views.span">[[views.span]]</a>
|
| 2 |
|
| 3 |
+
##### Overview <a id="span.overview">[[span.overview]]</a>
|
| 4 |
|
| 5 |
A `span` is a view over a contiguous sequence of objects, the storage of
|
| 6 |
which is owned by some other object.
|
| 7 |
|
| 8 |
All member functions of `span` have constant time complexity.
|
|
|
|
| 20 |
using pointer = element_type*;
|
| 21 |
using const_pointer = const element_type*;
|
| 22 |
using reference = element_type&;
|
| 23 |
using const_reference = const element_type&;
|
| 24 |
using iterator = implementation-defined // type of span::iterator; // see [span.iterators]
|
| 25 |
+
using const_iterator = std::const_iterator<iterator>;
|
| 26 |
using reverse_iterator = std::reverse_iterator<iterator>;
|
| 27 |
+
using const_reverse_iterator = std::const_iterator<reverse_iterator>;
|
| 28 |
static constexpr size_type extent = Extent;
|
| 29 |
|
| 30 |
// [span.cons], constructors, copy, and assignment
|
| 31 |
constexpr span() noexcept;
|
| 32 |
template<class It>
|
|
|
|
| 74 |
constexpr pointer data() const noexcept;
|
| 75 |
|
| 76 |
// [span.iterators], iterator support
|
| 77 |
constexpr iterator begin() const noexcept;
|
| 78 |
constexpr iterator end() const noexcept;
|
| 79 |
+
constexpr const_iterator cbegin() const noexcept { return begin(); }
|
| 80 |
+
constexpr const_iterator cend() const noexcept { return end(); }
|
| 81 |
constexpr reverse_iterator rbegin() const noexcept;
|
| 82 |
constexpr reverse_iterator rend() const noexcept;
|
| 83 |
+
constexpr const_reverse_iterator crbegin() const noexcept { return rbegin(); }
|
| 84 |
+
constexpr const_reverse_iterator crend() const noexcept { return rend(); }
|
| 85 |
|
| 86 |
private:
|
| 87 |
pointer data_; // exposition only
|
| 88 |
size_type size_; // exposition only
|
| 89 |
};
|
|
|
|
| 99 |
template<class R>
|
| 100 |
span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
|
| 101 |
}
|
| 102 |
```
|
| 103 |
|
| 104 |
+
`span<ElementType, Extent>` is a trivially copyable type
|
| 105 |
+
[[term.trivially.copyable.type]].
|
| 106 |
+
|
| 107 |
`ElementType` is required to be a complete object type that is not an
|
| 108 |
abstract class type.
|
| 109 |
|
| 110 |
+
##### Constructors, copy, and assignment <a id="span.cons">[[span.cons]]</a>
|
| 111 |
|
| 112 |
``` cpp
|
| 113 |
constexpr span() noexcept;
|
| 114 |
```
|
| 115 |
|
|
|
|
| 134 |
- \[`first`, `first + count`) is a valid range.
|
| 135 |
- `It` models `contiguous_iterator`.
|
| 136 |
- If `extent` is not equal to `dynamic_extent`, then `count` is equal to
|
| 137 |
`extent`.
|
| 138 |
|
| 139 |
+
*Effects:* Initializes *`data_`* with `to_address(first)` and *`size_`*
|
| 140 |
+
with `count`.
|
| 141 |
|
| 142 |
*Throws:* Nothing.
|
| 143 |
|
| 144 |
``` cpp
|
| 145 |
template<class It, class End>
|
|
|
|
| 161 |
equal to `extent`.
|
| 162 |
- \[`first`, `last`) is a valid range.
|
| 163 |
- `It` models `contiguous_iterator`.
|
| 164 |
- `End` models `sized_sentinel_for<It>`.
|
| 165 |
|
| 166 |
+
*Effects:* Initializes *`data_`* with `to_address(first)` and *`size_`*
|
| 167 |
+
with `last - first`.
|
| 168 |
|
| 169 |
*Throws:* When and what `last - first` throws.
|
| 170 |
|
| 171 |
``` cpp
|
| 172 |
template<size_t N> constexpr span(type_identity_t<element_type> (&arr)[N]) noexcept;
|
|
|
|
| 211 |
is equal to `extent`.
|
| 212 |
- `R` models `ranges::contiguous_range` and `ranges::sized_range`.
|
| 213 |
- If `is_const_v<element_type>` is `false`, `R` models
|
| 214 |
`ranges::borrowed_range`.
|
| 215 |
|
| 216 |
+
*Effects:* Initializes *`data_`* with `ranges::data(r)` and *`size_`*
|
| 217 |
+
with `ranges::size(r)`.
|
| 218 |
|
| 219 |
*Throws:* What and when `ranges::data(r)` and `ranges::size(r)` throw.
|
| 220 |
|
| 221 |
``` cpp
|
| 222 |
constexpr span(const span& other) noexcept = default;
|
|
|
|
| 256 |
constexpr span& operator=(const span& other) noexcept = default;
|
| 257 |
```
|
| 258 |
|
| 259 |
*Ensures:* `size() == other.size() && data() == other.data()`.
|
| 260 |
|
| 261 |
+
##### Deduction guides <a id="span.deduct">[[span.deduct]]</a>
|
| 262 |
|
| 263 |
``` cpp
|
| 264 |
template<class It, class EndOrSize>
|
| 265 |
span(It, EndOrSize) -> span<remove_reference_t<iter_reference_t<It>>>;
|
| 266 |
```
|
|
|
|
| 272 |
span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
|
| 273 |
```
|
| 274 |
|
| 275 |
*Constraints:* `R` satisfies `ranges::contiguous_range`.
|
| 276 |
|
| 277 |
+
##### Subviews <a id="span.sub">[[span.sub]]</a>
|
| 278 |
|
| 279 |
``` cpp
|
| 280 |
template<size_t Count> constexpr span<element_type, Count> first() const;
|
| 281 |
```
|
| 282 |
|
|
|
|
| 367 |
|
| 368 |
``` cpp
|
| 369 |
return {data() + offset, count == dynamic_extent ? size() - offset : count};
|
| 370 |
```
|
| 371 |
|
| 372 |
+
##### Observers <a id="span.obs">[[span.obs]]</a>
|
| 373 |
|
| 374 |
``` cpp
|
| 375 |
constexpr size_type size() const noexcept;
|
| 376 |
```
|
| 377 |
|
| 378 |
+
*Effects:* Equivalent to: `return `*`size_`*`;`
|
| 379 |
|
| 380 |
``` cpp
|
| 381 |
constexpr size_type size_bytes() const noexcept;
|
| 382 |
```
|
| 383 |
|
|
|
|
| 387 |
[[nodiscard]] constexpr bool empty() const noexcept;
|
| 388 |
```
|
| 389 |
|
| 390 |
*Effects:* Equivalent to: `return size() == 0;`
|
| 391 |
|
| 392 |
+
##### Element access <a id="span.elem">[[span.elem]]</a>
|
| 393 |
|
| 394 |
``` cpp
|
| 395 |
constexpr reference operator[](size_type idx) const;
|
| 396 |
```
|
| 397 |
|
|
|
|
| 417 |
|
| 418 |
``` cpp
|
| 419 |
constexpr pointer data() const noexcept;
|
| 420 |
```
|
| 421 |
|
| 422 |
+
*Effects:* Equivalent to: `return `*`data_`*`;`
|
| 423 |
|
| 424 |
+
##### Iterator support <a id="span.iterators">[[span.iterators]]</a>
|
| 425 |
|
| 426 |
``` cpp
|
| 427 |
using iterator = implementation-defined // type of span::iterator;
|
| 428 |
```
|
| 429 |
|
| 430 |
The type models `contiguous_iterator` [[iterator.concept.contiguous]],
|
| 431 |
meets the *Cpp17RandomAccessIterator*
|
| 432 |
requirements [[random.access.iterators]], and meets the requirements for
|
| 433 |
+
constexpr iterators [[iterator.requirements.general]], whose value type
|
| 434 |
+
is `value_type` and whose reference type is `reference`.
|
| 435 |
+
|
| 436 |
+
All requirements on container iterators [[container.reqmts]] apply to
|
| 437 |
`span::iterator` as well.
|
| 438 |
|
| 439 |
``` cpp
|
| 440 |
constexpr iterator begin() const noexcept;
|
| 441 |
```
|
|
|
|
| 459 |
constexpr reverse_iterator rend() const noexcept;
|
| 460 |
```
|
| 461 |
|
| 462 |
*Effects:* Equivalent to: `return reverse_iterator(begin());`
|
| 463 |
|
|
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