17fd3f55e9
- Implement a simple `IterSpan` for passing iterators with size. - Use shared memory for column size counts. - Use one thread for each sample in row count to reduce atomic operations.
720 lines
23 KiB
C++
720 lines
23 KiB
C++
/**
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* Copyright 2018-2023, XGBoost contributors
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* \brief span class based on ISO++20 span
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*
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* About NOLINTs in this file:
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*
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* If we want Span to work with std interface, like range for loop, the
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* naming must be consistent with std, not XGBoost. Also, the interface also
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* conflicts with XGBoost coding style, specifically, the use of `explicit'
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* keyword.
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*
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*
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* Some of the code is copied from Guidelines Support Library, here is the
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* license:
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*
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* Copyright (c) 2015 Microsoft Corporation. All rights reserved.
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*
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* This code is licensed under the MIT License (MIT).
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef XGBOOST_SPAN_H_
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#define XGBOOST_SPAN_H_
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#include <xgboost/base.h>
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#include <xgboost/logging.h>
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#include <cinttypes> // size_t
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#include <cstdio>
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#include <iterator>
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#include <limits> // numeric_limits
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#include <type_traits>
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#include <utility> // for move
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#if defined(__CUDACC__)
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#include <cuda_runtime.h>
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#endif // defined(__CUDACC__)
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/*!
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* The version number 1910 is picked up from GSL.
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*
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* We might want to use MOODYCAMEL_NOEXCEPT from dmlc/concurrentqueue.h. But
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* there are a lot more definitions in that file would cause warnings/troubles
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* in MSVC 2013. Currently we try to keep the closure of Span as minimal as
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* possible.
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*
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* There are other workarounds for MSVC, like _Unwrapped, _Verify_range ...
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* Some of these are hidden magics of MSVC and I tried to avoid them. Should any
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* of them become needed, please consult the source code of GSL, and possibly
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* some explanations from this thread:
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*
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* https://github.com/Microsoft/GSL/pull/664
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*
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* TODO(trivialfis): Group these MSVC workarounds into a manageable place.
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*/
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#if defined(_MSC_VER) && _MSC_VER < 1910
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#define __span_noexcept
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#pragma push_macro("constexpr")
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#define constexpr /*constexpr*/
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#else
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#define __span_noexcept noexcept
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#endif // defined(_MSC_VER) && _MSC_VER < 1910
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namespace xgboost {
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namespace common {
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#if defined(__CUDA_ARCH__)
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// Usual logging facility is not available inside device code.
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#if defined(_MSC_VER)
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// Windows CUDA doesn't have __assert_fail.
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#define CUDA_KERNEL_CHECK(cond) \
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do { \
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if (XGBOOST_EXPECT(!(cond), false)) { \
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asm("trap;"); \
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} \
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} while (0)
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#else // defined(_MSC_VER)
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#define __ASSERT_STR_HELPER(x) #x
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#define CUDA_KERNEL_CHECK(cond) \
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(XGBOOST_EXPECT((cond), true) \
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? static_cast<void>(0) \
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: __assert_fail(__ASSERT_STR_HELPER((cond)), __FILE__, __LINE__, __PRETTY_FUNCTION__))
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#endif // defined(_MSC_VER)
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#define KERNEL_CHECK CUDA_KERNEL_CHECK
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#define SPAN_CHECK KERNEL_CHECK
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#else // ------------------------------ not CUDA ----------------------------
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#if defined(XGBOOST_STRICT_R_MODE) && XGBOOST_STRICT_R_MODE == 1
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#define KERNEL_CHECK(cond)
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#define SPAN_CHECK(cond) KERNEL_CHECK(cond)
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#else
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#define KERNEL_CHECK(cond) (XGBOOST_EXPECT((cond), true) ? static_cast<void>(0) : std::terminate())
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#define SPAN_CHECK(cond) KERNEL_CHECK(cond)
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#endif // defined(XGBOOST_STRICT_R_MODE)
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#endif // __CUDA_ARCH__
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#define SPAN_LT(lhs, rhs) SPAN_CHECK((lhs) < (rhs))
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namespace detail {
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/*!
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* By default, XGBoost uses uint32_t for indexing data. int64_t covers all
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* values uint32_t can represent. Also, On x86-64 Linux, GCC uses long int to
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* represent ptrdiff_t, which is just int64_t. So we make it deterministic
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* here.
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*/
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using ptrdiff_t = typename std::conditional< // NOLINT
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std::is_same<std::ptrdiff_t, std::int64_t>::value,
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std::ptrdiff_t, std::int64_t>::type;
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} // namespace detail
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#if defined(_MSC_VER) && _MSC_VER < 1910
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constexpr const std::size_t
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dynamic_extent = std::numeric_limits<std::size_t>::max(); // NOLINT
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#else
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constexpr std::size_t dynamic_extent = std::numeric_limits<std::size_t>::max(); // NOLINT
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#endif // defined(_MSC_VER) && _MSC_VER < 1910
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enum class byte : unsigned char {}; // NOLINT
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template <class ElementType, std::size_t Extent>
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class Span;
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namespace detail {
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template <typename SpanType, bool IsConst>
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class SpanIterator {
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using ElementType = typename SpanType::element_type;
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public:
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using iterator_category = std::random_access_iterator_tag; // NOLINT
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using value_type = typename SpanType::value_type; // NOLINT
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using difference_type = detail::ptrdiff_t; // NOLINT
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using reference = typename std::conditional< // NOLINT
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IsConst, const ElementType, ElementType>::type&;
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using pointer = typename std::add_pointer<reference>::type; // NOLINT
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constexpr SpanIterator() = default;
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XGBOOST_DEVICE constexpr SpanIterator(
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const SpanType* _span,
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typename SpanType::index_type _idx) __span_noexcept :
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span_(_span), index_(_idx) {}
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friend SpanIterator<SpanType, true>;
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template <bool B, typename std::enable_if<!B && IsConst>::type* = nullptr>
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XGBOOST_DEVICE constexpr SpanIterator( // NOLINT
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const SpanIterator<SpanType, B>& other_) __span_noexcept
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: SpanIterator(other_.span_, other_.index_) {}
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XGBOOST_DEVICE reference operator*() const {
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SPAN_CHECK(index_ < span_->size());
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return *(span_->data() + index_);
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}
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XGBOOST_DEVICE reference operator[](difference_type n) const {
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return *(*this + n);
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}
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XGBOOST_DEVICE pointer operator->() const {
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SPAN_CHECK(index_ != span_->size());
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return span_->data() + index_;
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}
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XGBOOST_DEVICE SpanIterator& operator++() {
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SPAN_CHECK(index_ != span_->size());
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index_++;
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return *this;
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}
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XGBOOST_DEVICE SpanIterator operator++(int) {
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auto ret = *this;
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++(*this);
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return ret;
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}
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XGBOOST_DEVICE SpanIterator& operator--() {
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SPAN_CHECK(index_ != 0 && index_ <= span_->size());
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index_--;
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return *this;
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}
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XGBOOST_DEVICE SpanIterator operator--(int) {
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auto ret = *this;
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--(*this);
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return ret;
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}
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XGBOOST_DEVICE SpanIterator operator+(difference_type n) const {
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auto ret = *this;
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return ret += n;
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}
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XGBOOST_DEVICE SpanIterator& operator+=(difference_type n) {
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SPAN_CHECK((index_ + n) <= span_->size());
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index_ += n;
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return *this;
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}
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XGBOOST_DEVICE difference_type operator-(SpanIterator rhs) const {
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SPAN_CHECK(span_ == rhs.span_);
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return index_ - rhs.index_;
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}
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XGBOOST_DEVICE SpanIterator operator-(difference_type n) const {
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auto ret = *this;
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return ret -= n;
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}
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XGBOOST_DEVICE SpanIterator& operator-=(difference_type n) {
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return *this += -n;
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}
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// friends
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XGBOOST_DEVICE constexpr friend bool operator==(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return _lhs.span_ == _rhs.span_ && _lhs.index_ == _rhs.index_;
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}
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XGBOOST_DEVICE constexpr friend bool operator!=(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return !(_lhs == _rhs);
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}
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XGBOOST_DEVICE constexpr friend bool operator<(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return _lhs.index_ < _rhs.index_;
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}
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XGBOOST_DEVICE constexpr friend bool operator<=(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return !(_rhs < _lhs);
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}
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XGBOOST_DEVICE constexpr friend bool operator>(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return _rhs < _lhs;
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}
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XGBOOST_DEVICE constexpr friend bool operator>=(
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SpanIterator _lhs, SpanIterator _rhs) __span_noexcept {
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return !(_rhs > _lhs);
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}
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protected:
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const SpanType *span_ { nullptr };
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typename SpanType::index_type index_ { 0 };
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};
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// It's tempting to use constexpr instead of structs to do the following meta
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// programming. But remember that we are supporting MSVC 2013 here.
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/*!
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* The extent E of the span returned by subspan is determined as follows:
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*
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* - If Count is not dynamic_extent, Count;
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* - Otherwise, if Extent is not dynamic_extent, Extent - Offset;
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* - Otherwise, dynamic_extent.
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*/
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template <std::size_t Extent, std::size_t Offset, std::size_t Count>
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struct ExtentValue : public std::integral_constant<
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std::size_t, Count != dynamic_extent ?
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Count : (Extent != dynamic_extent ? Extent - Offset : Extent)> {};
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/*!
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* If N is dynamic_extent, the extent of the returned span E is also
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* dynamic_extent; otherwise it is std::size_t(sizeof(T)) * N.
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*/
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template <typename T, std::size_t Extent>
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struct ExtentAsBytesValue : public std::integral_constant<
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std::size_t,
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Extent == dynamic_extent ?
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Extent : sizeof(T) * Extent> {};
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template <std::size_t From, std::size_t To>
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struct IsAllowedExtentConversion : public std::integral_constant<
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bool, From == To || From == dynamic_extent || To == dynamic_extent> {};
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template <class From, class To>
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struct IsAllowedElementTypeConversion : public std::integral_constant<
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bool, std::is_convertible<From(*)[], To(*)[]>::value> {};
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template <class T>
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struct IsSpanOracle : std::false_type {};
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template <class T, std::size_t Extent>
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struct IsSpanOracle<Span<T, Extent>> : std::true_type {};
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template <class T>
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struct IsSpan : public IsSpanOracle<typename std::remove_cv<T>::type> {};
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// Re-implement std algorithms here to adopt CUDA.
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template <typename T>
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struct Less {
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XGBOOST_DEVICE constexpr bool operator()(const T& _x, const T& _y) const {
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return _x < _y;
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}
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};
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template <typename T>
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struct Greater {
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XGBOOST_DEVICE constexpr bool operator()(const T& _x, const T& _y) const {
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return _x > _y;
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}
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};
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template <class InputIt1, class InputIt2,
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class Compare =
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detail::Less<decltype(std::declval<InputIt1>().operator*())>>
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XGBOOST_DEVICE bool LexicographicalCompare(InputIt1 first1, InputIt1 last1,
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InputIt2 first2, InputIt2 last2) {
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Compare comp;
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for (; first1 != last1 && first2 != last2; ++first1, ++first2) {
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if (comp(*first1, *first2)) {
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return true;
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}
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if (comp(*first2, *first1)) {
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return false;
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}
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}
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return first1 == last1 && first2 != last2;
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}
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} // namespace detail
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/*!
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* \brief span class implementation, based on ISO++20 span<T>. The interface
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* should be the same.
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*
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* What's different from span<T> in Guidelines Support Library (GSL)
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*
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* Interface might be slightly different, we stick with ISO.
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*
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* GSL uses C++14/17 features, which are not available here.
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* GSL uses constexpr extensively, which is not possible with limitation
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* of C++11.
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* GSL doesn't concern about CUDA.
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*
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* GSL is more thoroughly implemented and tested.
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* GSL is more optimized, especially for static extent.
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*
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* GSL uses __buildin_unreachable() when error, Span<T> uses dmlc LOG and
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* customized CUDA logging.
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*
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*
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* What's different from span<T> in ISO++20 (ISO)
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*
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* ISO uses functions/structs from std library, which might be not available
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* in CUDA.
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* Initializing from std::array is not supported.
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*
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* ISO uses constexpr extensively, which is not possible with limitation
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* of C++11.
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* ISO uses C++14/17 features, which is not available here.
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* ISO doesn't concern about CUDA.
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*
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* ISO uses std::terminate(), Span<T> uses dmlc LOG and customized CUDA
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* logging.
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*
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*
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* Limitations:
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* With thrust:
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* It's not adviced to initialize Span with host_vector directly, since
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* host_vector::data() is a host function.
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* It's not possible to initialize Span with device_vector directly, since
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* device_vector::data() returns a wrapped pointer.
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* It's unclear that what kind of thrust algorithm can be used without
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* memory error. See the test case "GPUSpan.WithTrust"
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*
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* Pass iterator to kernel:
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* Not possible. Use subspan instead.
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*
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* The underlying Span in SpanIterator is a pointer, but CUDA pass kernel
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* parameter by value. If we were to hold a Span value instead of a
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* pointer, the following snippet will crash, violating the safety
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* purpose of Span:
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*
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* \code{.cpp}
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* Span<float> span {arr_a};
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* auto beg = span.begin();
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*
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* Span<float> span_b = arr_b;
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* span = span_b;
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*
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* delete arr_a;
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* beg++; // crash
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* \endcode
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*
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* While holding a pointer or reference should avoid the problem, it's a
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* compromise. Since we have subspan, it's acceptable not to support
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* passing iterator.
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*/
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template <typename T,
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std::size_t Extent = dynamic_extent>
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class Span {
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public:
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using element_type = T; // NOLINT
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using value_type = typename std::remove_cv<T>::type; // NOLINT
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using index_type = std::size_t; // NOLINT
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using difference_type = detail::ptrdiff_t; // NOLINT
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using pointer = T*; // NOLINT
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using reference = T&; // NOLINT
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using iterator = detail::SpanIterator<Span<T, Extent>, false>; // NOLINT
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using const_iterator = const detail::SpanIterator<Span<T, Extent>, true>; // NOLINT
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using reverse_iterator = std::reverse_iterator<iterator>; // NOLINT
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using const_reverse_iterator = const std::reverse_iterator<const_iterator>; // NOLINT
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// constructors
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constexpr Span() __span_noexcept = default;
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XGBOOST_DEVICE Span(pointer _ptr, index_type _count) :
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size_(_count), data_(_ptr) {
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SPAN_CHECK(!(Extent != dynamic_extent && _count != Extent));
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SPAN_CHECK(_ptr || _count == 0);
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}
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XGBOOST_DEVICE Span(pointer _first, pointer _last) :
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size_(_last - _first), data_(_first) {
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SPAN_CHECK(data_ || size_ == 0);
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}
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template <std::size_t N>
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XGBOOST_DEVICE constexpr Span(element_type (&arr)[N]) // NOLINT
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__span_noexcept : size_(N), data_(&arr[0]) {}
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template <class Container,
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class = typename std::enable_if<
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!std::is_const<element_type>::value &&
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!detail::IsSpan<Container>::value &&
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std::is_convertible<typename Container::pointer, pointer>::value &&
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std::is_convertible<typename Container::pointer,
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decltype(std::declval<Container>().data())>::value>::type>
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Span(Container& _cont) : // NOLINT
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size_(_cont.size()), data_(_cont.data()) {
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static_assert(!detail::IsSpan<Container>::value, "Wrong constructor of Span is called.");
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}
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template <class Container,
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class = typename std::enable_if<
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std::is_const<element_type>::value &&
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!detail::IsSpan<Container>::value &&
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std::is_convertible<typename Container::pointer, pointer>::value &&
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std::is_convertible<typename Container::pointer,
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decltype(std::declval<Container>().data())>::value>::type>
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Span(const Container& _cont) : size_(_cont.size()), // NOLINT
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data_(_cont.data()) {
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static_assert(!detail::IsSpan<Container>::value, "Wrong constructor of Span is called.");
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}
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template <class U, std::size_t OtherExtent,
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class = typename std::enable_if<
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detail::IsAllowedElementTypeConversion<U, T>::value &&
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detail::IsAllowedExtentConversion<OtherExtent, Extent>::value>>
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XGBOOST_DEVICE constexpr Span(const Span<U, OtherExtent>& _other) // NOLINT
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__span_noexcept : size_(_other.size()), data_(_other.data()) {}
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XGBOOST_DEVICE constexpr Span(const Span& _other)
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__span_noexcept : size_(_other.size()), data_(_other.data()) {}
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XGBOOST_DEVICE Span& operator=(const Span& _other) __span_noexcept {
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size_ = _other.size();
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data_ = _other.data();
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return *this;
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}
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XGBOOST_DEVICE ~Span() __span_noexcept {}; // NOLINT
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XGBOOST_DEVICE constexpr iterator begin() const __span_noexcept { // NOLINT
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return {this, 0};
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}
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XGBOOST_DEVICE constexpr iterator end() const __span_noexcept { // NOLINT
|
|
return {this, size()};
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr const_iterator cbegin() const __span_noexcept { // NOLINT
|
|
return {this, 0};
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr const_iterator cend() const __span_noexcept { // NOLINT
|
|
return {this, size()};
|
|
}
|
|
|
|
constexpr reverse_iterator rbegin() const __span_noexcept { // NOLINT
|
|
return reverse_iterator{end()};
|
|
}
|
|
|
|
constexpr reverse_iterator rend() const __span_noexcept { // NOLINT
|
|
return reverse_iterator{begin()};
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr const_reverse_iterator crbegin() const __span_noexcept { // NOLINT
|
|
return const_reverse_iterator{cend()};
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr const_reverse_iterator crend() const __span_noexcept { // NOLINT
|
|
return const_reverse_iterator{cbegin()};
|
|
}
|
|
|
|
// element access
|
|
|
|
XGBOOST_DEVICE reference front() const { // NOLINT
|
|
return (*this)[0];
|
|
}
|
|
|
|
XGBOOST_DEVICE reference back() const { // NOLINT
|
|
return (*this)[size() - 1];
|
|
}
|
|
|
|
XGBOOST_DEVICE reference operator[](index_type _idx) const {
|
|
SPAN_LT(_idx, size());
|
|
return data()[_idx];
|
|
}
|
|
|
|
XGBOOST_DEVICE reference operator()(index_type _idx) const {
|
|
return this->operator[](_idx);
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr pointer data() const __span_noexcept { // NOLINT
|
|
return data_;
|
|
}
|
|
|
|
// Observers
|
|
XGBOOST_DEVICE constexpr index_type size() const __span_noexcept { // NOLINT
|
|
return size_;
|
|
}
|
|
XGBOOST_DEVICE constexpr index_type size_bytes() const __span_noexcept { // NOLINT
|
|
return size() * sizeof(T);
|
|
}
|
|
|
|
XGBOOST_DEVICE constexpr bool empty() const __span_noexcept { // NOLINT
|
|
return size() == 0;
|
|
}
|
|
|
|
// Subviews
|
|
template <std::size_t Count>
|
|
XGBOOST_DEVICE Span<element_type, Count> first() const { // NOLINT
|
|
SPAN_CHECK(Count <= size());
|
|
return {data(), Count};
|
|
}
|
|
|
|
XGBOOST_DEVICE Span<element_type, dynamic_extent> first( // NOLINT
|
|
std::size_t _count) const {
|
|
SPAN_CHECK(_count <= size());
|
|
return {data(), _count};
|
|
}
|
|
|
|
template <std::size_t Count>
|
|
XGBOOST_DEVICE Span<element_type, Count> last() const { // NOLINT
|
|
SPAN_CHECK(Count <= size());
|
|
return {data() + size() - Count, Count};
|
|
}
|
|
|
|
XGBOOST_DEVICE Span<element_type, dynamic_extent> last( // NOLINT
|
|
std::size_t _count) const {
|
|
SPAN_CHECK(_count <= size());
|
|
return subspan(size() - _count, _count);
|
|
}
|
|
|
|
/*!
|
|
* If Count is std::dynamic_extent, r.size() == this->size() - Offset;
|
|
* Otherwise r.size() == Count.
|
|
*/
|
|
template <std::size_t Offset,
|
|
std::size_t Count = dynamic_extent>
|
|
XGBOOST_DEVICE auto subspan() const -> // NOLINT
|
|
Span<element_type,
|
|
detail::ExtentValue<Extent, Offset, Count>::value> {
|
|
SPAN_CHECK((Count == dynamic_extent) ?
|
|
(Offset <= size()) : (Offset + Count <= size()));
|
|
return {data() + Offset, Count == dynamic_extent ? size() - Offset : Count};
|
|
}
|
|
|
|
XGBOOST_DEVICE Span<element_type, dynamic_extent> subspan( // NOLINT
|
|
index_type _offset,
|
|
index_type _count = dynamic_extent) const {
|
|
SPAN_CHECK((_count == dynamic_extent) ?
|
|
(_offset <= size()) : (_offset + _count <= size()));
|
|
return {data() + _offset, _count ==
|
|
dynamic_extent ? size() - _offset : _count};
|
|
}
|
|
|
|
private:
|
|
index_type size_ { 0 };
|
|
pointer data_ { nullptr };
|
|
};
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE bool operator==(Span<T, X> l, Span<U, Y> r) {
|
|
if (l.size() != r.size()) {
|
|
return false;
|
|
}
|
|
for (auto l_beg = l.cbegin(), r_beg = r.cbegin(); l_beg != l.cend();
|
|
++l_beg, ++r_beg) {
|
|
if (*l_beg != *r_beg) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE constexpr bool operator!=(Span<T, X> l, Span<U, Y> r) {
|
|
return !(l == r);
|
|
}
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE constexpr bool operator<(Span<T, X> l, Span<U, Y> r) {
|
|
return detail::LexicographicalCompare(l.begin(), l.end(),
|
|
r.begin(), r.end());
|
|
}
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE constexpr bool operator<=(Span<T, X> l, Span<U, Y> r) {
|
|
return !(l > r);
|
|
}
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE constexpr bool operator>(Span<T, X> l, Span<U, Y> r) {
|
|
return detail::LexicographicalCompare<
|
|
typename Span<T, X>::iterator, typename Span<U, Y>::iterator,
|
|
detail::Greater<typename Span<T, X>::element_type>>(l.begin(), l.end(),
|
|
r.begin(), r.end());
|
|
}
|
|
|
|
template <class T, std::size_t X, class U, std::size_t Y>
|
|
XGBOOST_DEVICE constexpr bool operator>=(Span<T, X> l, Span<U, Y> r) {
|
|
return !(l < r);
|
|
}
|
|
|
|
template <class T, std::size_t E>
|
|
XGBOOST_DEVICE auto as_bytes(Span<T, E> s) __span_noexcept -> // NOLINT
|
|
Span<const byte, detail::ExtentAsBytesValue<T, E>::value> {
|
|
return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
|
|
}
|
|
|
|
template <class T, std::size_t E>
|
|
XGBOOST_DEVICE auto as_writable_bytes(Span<T, E> s) __span_noexcept -> // NOLINT
|
|
Span<byte, detail::ExtentAsBytesValue<T, E>::value> {
|
|
return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
|
|
}
|
|
|
|
/**
|
|
* \brief A simple custom Span type that uses general iterator instead of pointer.
|
|
*/
|
|
template <typename It>
|
|
class IterSpan {
|
|
public:
|
|
using value_type = typename std::iterator_traits<It>::value_type; // NOLINT
|
|
using index_type = std::size_t; // NOLINT
|
|
using iterator = It; // NOLINT
|
|
|
|
private:
|
|
It it_;
|
|
index_type size_{0};
|
|
|
|
public:
|
|
IterSpan() = default;
|
|
XGBOOST_DEVICE IterSpan(It it, index_type size) : it_{std::move(it)}, size_{size} {}
|
|
XGBOOST_DEVICE explicit IterSpan(common::Span<It, dynamic_extent> span)
|
|
: it_{span.data()}, size_{span.size()} {}
|
|
|
|
[[nodiscard]] XGBOOST_DEVICE index_type size() const noexcept { return size_; } // NOLINT
|
|
[[nodiscard]] XGBOOST_DEVICE decltype(auto) operator[](index_type i) const { return it_[i]; }
|
|
[[nodiscard]] XGBOOST_DEVICE decltype(auto) operator[](index_type i) { return it_[i]; }
|
|
[[nodiscard]] XGBOOST_DEVICE bool empty() const noexcept { return size() == 0; } // NOLINT
|
|
[[nodiscard]] XGBOOST_DEVICE It data() const noexcept { return it_; } // NOLINT
|
|
[[nodiscard]] XGBOOST_DEVICE IterSpan<It> subspan( // NOLINT
|
|
index_type _offset, index_type _count = dynamic_extent) const {
|
|
SPAN_CHECK((_count == dynamic_extent) ? (_offset <= size()) : (_offset + _count <= size()));
|
|
return {data() + _offset, _count == dynamic_extent ? size() - _offset : _count};
|
|
}
|
|
[[nodiscard]] XGBOOST_DEVICE constexpr iterator begin() const noexcept { // NOLINT
|
|
return {this, 0};
|
|
}
|
|
[[nodiscard]] XGBOOST_DEVICE constexpr iterator end() const noexcept { // NOLINT
|
|
return {this, size()};
|
|
}
|
|
};
|
|
} // namespace common
|
|
} // namespace xgboost
|
|
|
|
#if defined(_MSC_VER) &&_MSC_VER < 1910
|
|
#undef constexpr
|
|
#pragma pop_macro("constexpr")
|
|
#undef __span_noexcept
|
|
#endif // _MSC_VER < 1910
|
|
|
|
#endif // XGBOOST_SPAN_H_
|