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Diffstat (limited to 'third_party/abseil_cpp/absl/container/fixed_array.h')
| -rw-r--r-- | third_party/abseil_cpp/absl/container/fixed_array.h | 527 |
1 files changed, 0 insertions, 527 deletions
diff --git a/third_party/abseil_cpp/absl/container/fixed_array.h b/third_party/abseil_cpp/absl/container/fixed_array.h deleted file mode 100644 index adf0dc8088..0000000000 --- a/third_party/abseil_cpp/absl/container/fixed_array.h +++ /dev/null @@ -1,527 +0,0 @@ -// Copyright 2018 The Abseil Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// https://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. -// -// ----------------------------------------------------------------------------- -// File: fixed_array.h -// ----------------------------------------------------------------------------- -// -// A `FixedArray<T>` represents a non-resizable array of `T` where the length of -// the array can be determined at run-time. It is a good replacement for -// non-standard and deprecated uses of `alloca()` and variable length arrays -// within the GCC extension. (See -// https://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html). -// -// `FixedArray` allocates small arrays inline, keeping performance fast by -// avoiding heap operations. It also helps reduce the chances of -// accidentally overflowing your stack if large input is passed to -// your function. - -#ifndef ABSL_CONTAINER_FIXED_ARRAY_H_ -#define ABSL_CONTAINER_FIXED_ARRAY_H_ - -#include <algorithm> -#include <cassert> -#include <cstddef> -#include <initializer_list> -#include <iterator> -#include <limits> -#include <memory> -#include <new> -#include <type_traits> - -#include "absl/algorithm/algorithm.h" -#include "absl/base/dynamic_annotations.h" -#include "absl/base/internal/throw_delegate.h" -#include "absl/base/macros.h" -#include "absl/base/optimization.h" -#include "absl/base/port.h" -#include "absl/container/internal/compressed_tuple.h" -#include "absl/memory/memory.h" - -namespace absl { -ABSL_NAMESPACE_BEGIN - -constexpr static auto kFixedArrayUseDefault = static_cast<size_t>(-1); - -// ----------------------------------------------------------------------------- -// FixedArray -// ----------------------------------------------------------------------------- -// -// A `FixedArray` provides a run-time fixed-size array, allocating a small array -// inline for efficiency. -// -// Most users should not specify an `inline_elements` argument and let -// `FixedArray` automatically determine the number of elements -// to store inline based on `sizeof(T)`. If `inline_elements` is specified, the -// `FixedArray` implementation will use inline storage for arrays with a -// length <= `inline_elements`. -// -// Note that a `FixedArray` constructed with a `size_type` argument will -// default-initialize its values by leaving trivially constructible types -// uninitialized (e.g. int, int[4], double), and others default-constructed. -// This matches the behavior of c-style arrays and `std::array`, but not -// `std::vector`. -// -// Note that `FixedArray` does not provide a public allocator; if it requires a -// heap allocation, it will do so with global `::operator new[]()` and -// `::operator delete[]()`, even if T provides class-scope overrides for these -// operators. -template <typename T, size_t N = kFixedArrayUseDefault, - typename A = std::allocator<T>> -class FixedArray { - static_assert(!std::is_array<T>::value || std::extent<T>::value > 0, - "Arrays with unknown bounds cannot be used with FixedArray."); - - static constexpr size_t kInlineBytesDefault = 256; - - using AllocatorTraits = std::allocator_traits<A>; - // std::iterator_traits isn't guaranteed to be SFINAE-friendly until C++17, - // but this seems to be mostly pedantic. - template <typename Iterator> - using EnableIfForwardIterator = absl::enable_if_t<std::is_convertible< - typename std::iterator_traits<Iterator>::iterator_category, - std::forward_iterator_tag>::value>; - static constexpr bool NoexceptCopyable() { - return std::is_nothrow_copy_constructible<StorageElement>::value && - absl::allocator_is_nothrow<allocator_type>::value; - } - static constexpr bool NoexceptMovable() { - return std::is_nothrow_move_constructible<StorageElement>::value && - absl::allocator_is_nothrow<allocator_type>::value; - } - static constexpr bool DefaultConstructorIsNonTrivial() { - return !absl::is_trivially_default_constructible<StorageElement>::value; - } - - public: - using allocator_type = typename AllocatorTraits::allocator_type; - using value_type = typename AllocatorTraits::value_type; - using pointer = typename AllocatorTraits::pointer; - using const_pointer = typename AllocatorTraits::const_pointer; - using reference = value_type&; - using const_reference = const value_type&; - using size_type = typename AllocatorTraits::size_type; - using difference_type = typename AllocatorTraits::difference_type; - using iterator = pointer; - using const_iterator = const_pointer; - using reverse_iterator = std::reverse_iterator<iterator>; - using const_reverse_iterator = std::reverse_iterator<const_iterator>; - - static constexpr size_type inline_elements = - (N == kFixedArrayUseDefault ? kInlineBytesDefault / sizeof(value_type) - : static_cast<size_type>(N)); - - FixedArray( - const FixedArray& other, - const allocator_type& a = allocator_type()) noexcept(NoexceptCopyable()) - : FixedArray(other.begin(), other.end(), a) {} - - FixedArray( - FixedArray&& other, - const allocator_type& a = allocator_type()) noexcept(NoexceptMovable()) - : FixedArray(std::make_move_iterator(other.begin()), - std::make_move_iterator(other.end()), a) {} - - // Creates an array object that can store `n` elements. - // Note that trivially constructible elements will be uninitialized. - explicit FixedArray(size_type n, const allocator_type& a = allocator_type()) - : storage_(n, a) { - if (DefaultConstructorIsNonTrivial()) { - memory_internal::ConstructRange(storage_.alloc(), storage_.begin(), - storage_.end()); - } - } - - // Creates an array initialized with `n` copies of `val`. - FixedArray(size_type n, const value_type& val, - const allocator_type& a = allocator_type()) - : storage_(n, a) { - memory_internal::ConstructRange(storage_.alloc(), storage_.begin(), - storage_.end(), val); - } - - // Creates an array initialized with the size and contents of `init_list`. - FixedArray(std::initializer_list<value_type> init_list, - const allocator_type& a = allocator_type()) - : FixedArray(init_list.begin(), init_list.end(), a) {} - - // Creates an array initialized with the elements from the input - // range. The array's size will always be `std::distance(first, last)`. - // REQUIRES: Iterator must be a forward_iterator or better. - template <typename Iterator, EnableIfForwardIterator<Iterator>* = nullptr> - FixedArray(Iterator first, Iterator last, - const allocator_type& a = allocator_type()) - : storage_(std::distance(first, last), a) { - memory_internal::CopyRange(storage_.alloc(), storage_.begin(), first, last); - } - - ~FixedArray() noexcept { - for (auto* cur = storage_.begin(); cur != storage_.end(); ++cur) { - AllocatorTraits::destroy(storage_.alloc(), cur); - } - } - - // Assignments are deleted because they break the invariant that the size of a - // `FixedArray` never changes. - void operator=(FixedArray&&) = delete; - void operator=(const FixedArray&) = delete; - - // FixedArray::size() - // - // Returns the length of the fixed array. - size_type size() const { return storage_.size(); } - - // FixedArray::max_size() - // - // Returns the largest possible value of `std::distance(begin(), end())` for a - // `FixedArray<T>`. This is equivalent to the most possible addressable bytes - // over the number of bytes taken by T. - constexpr size_type max_size() const { - return (std::numeric_limits<difference_type>::max)() / sizeof(value_type); - } - - // FixedArray::empty() - // - // Returns whether or not the fixed array is empty. - bool empty() const { return size() == 0; } - - // FixedArray::memsize() - // - // Returns the memory size of the fixed array in bytes. - size_t memsize() const { return size() * sizeof(value_type); } - - // FixedArray::data() - // - // Returns a const T* pointer to elements of the `FixedArray`. This pointer - // can be used to access (but not modify) the contained elements. - const_pointer data() const { return AsValueType(storage_.begin()); } - - // Overload of FixedArray::data() to return a T* pointer to elements of the - // fixed array. This pointer can be used to access and modify the contained - // elements. - pointer data() { return AsValueType(storage_.begin()); } - - // FixedArray::operator[] - // - // Returns a reference the ith element of the fixed array. - // REQUIRES: 0 <= i < size() - reference operator[](size_type i) { - ABSL_HARDENING_ASSERT(i < size()); - return data()[i]; - } - - // Overload of FixedArray::operator()[] to return a const reference to the - // ith element of the fixed array. - // REQUIRES: 0 <= i < size() - const_reference operator[](size_type i) const { - ABSL_HARDENING_ASSERT(i < size()); - return data()[i]; - } - - // FixedArray::at - // - // Bounds-checked access. Returns a reference to the ith element of the - // fiexed array, or throws std::out_of_range - reference at(size_type i) { - if (ABSL_PREDICT_FALSE(i >= size())) { - base_internal::ThrowStdOutOfRange("FixedArray::at failed bounds check"); - } - return data()[i]; - } - - // Overload of FixedArray::at() to return a const reference to the ith element - // of the fixed array. - const_reference at(size_type i) const { - if (ABSL_PREDICT_FALSE(i >= size())) { - base_internal::ThrowStdOutOfRange("FixedArray::at failed bounds check"); - } - return data()[i]; - } - - // FixedArray::front() - // - // Returns a reference to the first element of the fixed array. - reference front() { - ABSL_HARDENING_ASSERT(!empty()); - return data()[0]; - } - - // Overload of FixedArray::front() to return a reference to the first element - // of a fixed array of const values. - const_reference front() const { - ABSL_HARDENING_ASSERT(!empty()); - return data()[0]; - } - - // FixedArray::back() - // - // Returns a reference to the last element of the fixed array. - reference back() { - ABSL_HARDENING_ASSERT(!empty()); - return data()[size() - 1]; - } - - // Overload of FixedArray::back() to return a reference to the last element - // of a fixed array of const values. - const_reference back() const { - ABSL_HARDENING_ASSERT(!empty()); - return data()[size() - 1]; - } - - // FixedArray::begin() - // - // Returns an iterator to the beginning of the fixed array. - iterator begin() { return data(); } - - // Overload of FixedArray::begin() to return a const iterator to the - // beginning of the fixed array. - const_iterator begin() const { return data(); } - - // FixedArray::cbegin() - // - // Returns a const iterator to the beginning of the fixed array. - const_iterator cbegin() const { return begin(); } - - // FixedArray::end() - // - // Returns an iterator to the end of the fixed array. - iterator end() { return data() + size(); } - - // Overload of FixedArray::end() to return a const iterator to the end of the - // fixed array. - const_iterator end() const { return data() + size(); } - - // FixedArray::cend() - // - // Returns a const iterator to the end of the fixed array. - const_iterator cend() const { return end(); } - - // FixedArray::rbegin() - // - // Returns a reverse iterator from the end of the fixed array. - reverse_iterator rbegin() { return reverse_iterator(end()); } - - // Overload of FixedArray::rbegin() to return a const reverse iterator from - // the end of the fixed array. - const_reverse_iterator rbegin() const { - return const_reverse_iterator(end()); - } - - // FixedArray::crbegin() - // - // Returns a const reverse iterator from the end of the fixed array. - const_reverse_iterator crbegin() const { return rbegin(); } - - // FixedArray::rend() - // - // Returns a reverse iterator from the beginning of the fixed array. - reverse_iterator rend() { return reverse_iterator(begin()); } - - // Overload of FixedArray::rend() for returning a const reverse iterator - // from the beginning of the fixed array. - const_reverse_iterator rend() const { - return const_reverse_iterator(begin()); - } - - // FixedArray::crend() - // - // Returns a reverse iterator from the beginning of the fixed array. - const_reverse_iterator crend() const { return rend(); } - - // FixedArray::fill() - // - // Assigns the given `value` to all elements in the fixed array. - void fill(const value_type& val) { std::fill(begin(), end(), val); } - - // Relational operators. Equality operators are elementwise using - // `operator==`, while order operators order FixedArrays lexicographically. - friend bool operator==(const FixedArray& lhs, const FixedArray& rhs) { - return absl::equal(lhs.begin(), lhs.end(), rhs.begin(), rhs.end()); - } - - friend bool operator!=(const FixedArray& lhs, const FixedArray& rhs) { - return !(lhs == rhs); - } - - friend bool operator<(const FixedArray& lhs, const FixedArray& rhs) { - return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), - rhs.end()); - } - - friend bool operator>(const FixedArray& lhs, const FixedArray& rhs) { - return rhs < lhs; - } - - friend bool operator<=(const FixedArray& lhs, const FixedArray& rhs) { - return !(rhs < lhs); - } - - friend bool operator>=(const FixedArray& lhs, const FixedArray& rhs) { - return !(lhs < rhs); - } - - template <typename H> - friend H AbslHashValue(H h, const FixedArray& v) { - return H::combine(H::combine_contiguous(std::move(h), v.data(), v.size()), - v.size()); - } - - private: - // StorageElement - // - // For FixedArrays with a C-style-array value_type, StorageElement is a POD - // wrapper struct called StorageElementWrapper that holds the value_type - // instance inside. This is needed for construction and destruction of the - // entire array regardless of how many dimensions it has. For all other cases, - // StorageElement is just an alias of value_type. - // - // Maintainer's Note: The simpler solution would be to simply wrap value_type - // in a struct whether it's an array or not. That causes some paranoid - // diagnostics to misfire, believing that 'data()' returns a pointer to a - // single element, rather than the packed array that it really is. - // e.g.: - // - // FixedArray<char> buf(1); - // sprintf(buf.data(), "foo"); - // - // error: call to int __builtin___sprintf_chk(etc...) - // will always overflow destination buffer [-Werror] - // - template <typename OuterT, typename InnerT = absl::remove_extent_t<OuterT>, - size_t InnerN = std::extent<OuterT>::value> - struct StorageElementWrapper { - InnerT array[InnerN]; - }; - - using StorageElement = - absl::conditional_t<std::is_array<value_type>::value, - StorageElementWrapper<value_type>, value_type>; - - static pointer AsValueType(pointer ptr) { return ptr; } - static pointer AsValueType(StorageElementWrapper<value_type>* ptr) { - return std::addressof(ptr->array); - } - - static_assert(sizeof(StorageElement) == sizeof(value_type), ""); - static_assert(alignof(StorageElement) == alignof(value_type), ""); - - class NonEmptyInlinedStorage { - public: - StorageElement* data() { return reinterpret_cast<StorageElement*>(buff_); } - void AnnotateConstruct(size_type n); - void AnnotateDestruct(size_type n); - -#ifdef ADDRESS_SANITIZER - void* RedzoneBegin() { return &redzone_begin_; } - void* RedzoneEnd() { return &redzone_end_ + 1; } -#endif // ADDRESS_SANITIZER - - private: - ADDRESS_SANITIZER_REDZONE(redzone_begin_); - alignas(StorageElement) char buff_[sizeof(StorageElement[inline_elements])]; - ADDRESS_SANITIZER_REDZONE(redzone_end_); - }; - - class EmptyInlinedStorage { - public: - StorageElement* data() { return nullptr; } - void AnnotateConstruct(size_type) {} - void AnnotateDestruct(size_type) {} - }; - - using InlinedStorage = - absl::conditional_t<inline_elements == 0, EmptyInlinedStorage, - NonEmptyInlinedStorage>; - - // Storage - // - // An instance of Storage manages the inline and out-of-line memory for - // instances of FixedArray. This guarantees that even when construction of - // individual elements fails in the FixedArray constructor body, the - // destructor for Storage will still be called and out-of-line memory will be - // properly deallocated. - // - class Storage : public InlinedStorage { - public: - Storage(size_type n, const allocator_type& a) - : size_alloc_(n, a), data_(InitializeData()) {} - - ~Storage() noexcept { - if (UsingInlinedStorage(size())) { - InlinedStorage::AnnotateDestruct(size()); - } else { - AllocatorTraits::deallocate(alloc(), AsValueType(begin()), size()); - } - } - - size_type size() const { return size_alloc_.template get<0>(); } - StorageElement* begin() const { return data_; } - StorageElement* end() const { return begin() + size(); } - allocator_type& alloc() { return size_alloc_.template get<1>(); } - - private: - static bool UsingInlinedStorage(size_type n) { - return n <= inline_elements; - } - - StorageElement* InitializeData() { - if (UsingInlinedStorage(size())) { - InlinedStorage::AnnotateConstruct(size()); - return InlinedStorage::data(); - } else { - return reinterpret_cast<StorageElement*>( - AllocatorTraits::allocate(alloc(), size())); - } - } - - // `CompressedTuple` takes advantage of EBCO for stateless `allocator_type`s - container_internal::CompressedTuple<size_type, allocator_type> size_alloc_; - StorageElement* data_; - }; - - Storage storage_; -}; - -template <typename T, size_t N, typename A> -constexpr size_t FixedArray<T, N, A>::kInlineBytesDefault; - -template <typename T, size_t N, typename A> -constexpr typename FixedArray<T, N, A>::size_type - FixedArray<T, N, A>::inline_elements; - -template <typename T, size_t N, typename A> -void FixedArray<T, N, A>::NonEmptyInlinedStorage::AnnotateConstruct( - typename FixedArray<T, N, A>::size_type n) { -#ifdef ADDRESS_SANITIZER - if (!n) return; - ANNOTATE_CONTIGUOUS_CONTAINER(data(), RedzoneEnd(), RedzoneEnd(), data() + n); - ANNOTATE_CONTIGUOUS_CONTAINER(RedzoneBegin(), data(), data(), RedzoneBegin()); -#endif // ADDRESS_SANITIZER - static_cast<void>(n); // Mark used when not in asan mode -} - -template <typename T, size_t N, typename A> -void FixedArray<T, N, A>::NonEmptyInlinedStorage::AnnotateDestruct( - typename FixedArray<T, N, A>::size_type n) { -#ifdef ADDRESS_SANITIZER - if (!n) return; - ANNOTATE_CONTIGUOUS_CONTAINER(data(), RedzoneEnd(), data() + n, RedzoneEnd()); - ANNOTATE_CONTIGUOUS_CONTAINER(RedzoneBegin(), data(), RedzoneBegin(), data()); -#endif // ADDRESS_SANITIZER - static_cast<void>(n); // Mark used when not in asan mode -} -ABSL_NAMESPACE_END -} // namespace absl - -#endif // ABSL_CONTAINER_FIXED_ARRAY_H_ |