| /* |
| * Copyright (C) 2021 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #pragma once |
| |
| #include <type_traits> |
| #include <wtf/StdLibExtras.h> |
| #include <wtf/Vector.h> |
| |
| namespace WTF { |
| |
| // TrailingArray offers the feature trailing array in the derived class. |
| // We can allocate a memory like the following layout. |
| // |
| // [ DerivedClass ][ Trailing Array ] |
| // |
| // And trailing array offers appropriate methods for accessing and destructions. |
| template<typename Derived, typename T> |
| class TrailingArray { |
| WTF_MAKE_NONCOPYABLE(TrailingArray); |
| friend class JSC::LLIntOffsetsExtractor; |
| public: |
| using value_type = T; |
| using pointer = T*; |
| using reference = T&; |
| using const_reference = const T&; |
| using const_pointer = const T*; |
| using size_type = unsigned; |
| using difference_type = std::make_signed_t<size_type>; |
| using iterator = T*; |
| using const_iterator = const T*; |
| using reverse_iterator = std::reverse_iterator<iterator>; |
| using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
| |
| explicit TrailingArray(unsigned size) |
| : m_size(size) |
| { |
| static_assert(std::is_final_v<Derived>); |
| VectorTypeOperations<T>::initializeIfNonPOD(begin(), end()); |
| } |
| |
| template<typename InputIterator> |
| TrailingArray(unsigned size, InputIterator first, InputIterator last) |
| : m_size(size) |
| { |
| static_assert(std::is_final_v<Derived>); |
| ASSERT(std::distance(first, last) == size); |
| std::uninitialized_copy(first, last, begin()); |
| } |
| |
| ~TrailingArray() |
| { |
| VectorTypeOperations<T>::destruct(begin(), end()); |
| } |
| |
| static constexpr size_t allocationSize(unsigned size) |
| { |
| return offsetOfData() + size * sizeof(T); |
| } |
| |
| unsigned size() const { return m_size; } |
| bool isEmpty() const { return !size(); } |
| unsigned byteSize() const { return size() * sizeof(T); } |
| |
| pointer data() { return bitwise_cast<T*>(bitwise_cast<uint8_t*>(static_cast<Derived*>(this)) + offsetOfData()); } |
| const_pointer data() const { return bitwise_cast<const T*>(bitwise_cast<const uint8_t*>(static_cast<const Derived*>(this)) + offsetOfData()); } |
| |
| iterator begin() { return data(); } |
| iterator end() { return data() + size(); } |
| const_iterator begin() const { return cbegin(); } |
| const_iterator end() const { return cend(); } |
| const_iterator cbegin() const { return data(); } |
| const_iterator cend() const { return data() + size(); } |
| |
| reverse_iterator rbegin() { return reverse_iterator(end()); } |
| reverse_iterator rend() { return reverse_iterator(begin()); } |
| const_reverse_iterator rbegin() const { return crbegin(); } |
| const_reverse_iterator rend() const { return crend(); } |
| const_reverse_iterator crbegin() const { return const_reverse_iterator(end()); } |
| const_reverse_iterator crend() const { return const_reverse_iterator(begin()); } |
| |
| reference at(unsigned i) |
| { |
| ASSERT(i < size()); |
| return begin()[i]; |
| } |
| |
| const_reference at(unsigned i) const |
| { |
| ASSERT(i < size()); |
| return begin()[i]; |
| } |
| |
| reference operator[](unsigned i) { return at(i); } |
| const_reference operator[](unsigned i) const { return at(i); } |
| |
| T& first() { return (*this)[0]; } |
| const T& first() const { return (*this)[0]; } |
| T& last() { return (*this)[size() - 1]; } |
| const T& last() const { return (*this)[size() - 1]; } |
| |
| void fill(const T& val) |
| { |
| std::fill(begin(), end(), val); |
| } |
| |
| static ptrdiff_t offsetOfSize() { return OBJECT_OFFSETOF(Derived, m_size); } |
| static constexpr ptrdiff_t offsetOfData() |
| { |
| return WTF::roundUpToMultipleOf<alignof(T)>(sizeof(Derived)); |
| } |
| |
| protected: |
| unsigned m_size { 0 }; |
| }; |
| |
| } // namespace WTF |
| |
| using WTF::TrailingArray; |