| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * 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 |
| * |
| * http://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. |
| */ |
| |
| #ifndef ART_LIBARTBASE_BASE_ARRAY_SLICE_H_ |
| #define ART_LIBARTBASE_BASE_ARRAY_SLICE_H_ |
| |
| #include "bit_utils.h" |
| #include "casts.h" |
| #include "iteration_range.h" |
| #include "stride_iterator.h" |
| |
| namespace art { |
| |
| // An ArraySlice is an abstraction over an array or a part of an array of a particular type. It does |
| // bounds checking and can be made from several common array-like structures in Art. |
| template <typename T> |
| class ArraySlice { |
| public: |
| using value_type = T; |
| using reference = T&; |
| using const_reference = const T&; |
| using pointer = T*; |
| using const_pointer = const T*; |
| using iterator = StrideIterator<T>; |
| using const_iterator = StrideIterator<const T>; |
| using reverse_iterator = std::reverse_iterator<iterator>; |
| using const_reverse_iterator = std::reverse_iterator<const_iterator>; |
| using difference_type = ptrdiff_t; |
| using size_type = size_t; |
| |
| // Create an empty array slice. |
| ArraySlice() : array_(nullptr), size_(0), element_size_(0) {} |
| |
| // Create an array slice of the first 'length' elements of the array, with each element being |
| // element_size bytes long. |
| ArraySlice(T* array, |
| size_t length, |
| size_t element_size = sizeof(T)) |
| : array_(array), |
| size_(dchecked_integral_cast<uint32_t>(length)), |
| element_size_(element_size) { |
| DCHECK(array_ != nullptr || length == 0); |
| } |
| |
| // Iterators. |
| iterator begin() { return iterator(&AtUnchecked(0), element_size_); } |
| const_iterator begin() const { return const_iterator(&AtUnchecked(0), element_size_); } |
| const_iterator cbegin() const { return const_iterator(&AtUnchecked(0), element_size_); } |
| StrideIterator<T> end() { return StrideIterator<T>(&AtUnchecked(size_), element_size_); } |
| const_iterator end() const { return const_iterator(&AtUnchecked(size_), element_size_); } |
| const_iterator cend() const { return const_iterator(&AtUnchecked(size_), element_size_); } |
| reverse_iterator rbegin() { return reverse_iterator(end()); } |
| const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); } |
| const_reverse_iterator crbegin() const { return const_reverse_iterator(cend()); } |
| reverse_iterator rend() { return reverse_iterator(begin()); } |
| const_reverse_iterator rend() const { return const_reverse_iterator(begin()); } |
| const_reverse_iterator crend() const { return const_reverse_iterator(cbegin()); } |
| |
| // Size. |
| size_type size() const { return size_; } |
| bool empty() const { return size() == 0u; } |
| |
| // Element access. NOTE: Not providing at() and data(). |
| |
| reference operator[](size_t index) { |
| DCHECK_LT(index, size_); |
| return AtUnchecked(index); |
| } |
| |
| const_reference operator[](size_t index) const { |
| DCHECK_LT(index, size_); |
| return AtUnchecked(index); |
| } |
| |
| reference front() { |
| DCHECK(!empty()); |
| return (*this)[0]; |
| } |
| |
| const_reference front() const { |
| DCHECK(!empty()); |
| return (*this)[0]; |
| } |
| |
| reference back() { |
| DCHECK(!empty()); |
| return (*this)[size_ - 1u]; |
| } |
| |
| const_reference back() const { |
| DCHECK(!empty()); |
| return (*this)[size_ - 1u]; |
| } |
| |
| ArraySlice<T> SubArray(size_type pos) { |
| return SubArray(pos, size() - pos); |
| } |
| |
| ArraySlice<const T> SubArray(size_type pos) const { |
| return SubArray(pos, size() - pos); |
| } |
| |
| ArraySlice<T> SubArray(size_type pos, size_type length) { |
| DCHECK_LE(pos, size()); |
| DCHECK_LE(length, size() - pos); |
| return ArraySlice<T>(&AtUnchecked(pos), length, element_size_); |
| } |
| |
| ArraySlice<const T> SubArray(size_type pos, size_type length) const { |
| DCHECK_LE(pos, size()); |
| DCHECK_LE(length, size() - pos); |
| return ArraySlice<const T>(&AtUnchecked(pos), length, element_size_); |
| } |
| |
| size_t ElementSize() const { |
| return element_size_; |
| } |
| |
| bool Contains(const T* element) const { |
| return &AtUnchecked(0) <= element && element < &AtUnchecked(size_); |
| } |
| |
| private: |
| T& AtUnchecked(size_t index) { |
| return *reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(array_) + index * element_size_); |
| } |
| |
| const T& AtUnchecked(size_t index) const { |
| return *reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(array_) + index * element_size_); |
| } |
| |
| T* array_; |
| size_t size_; |
| size_t element_size_; |
| }; |
| |
| } // namespace art |
| |
| #endif // ART_LIBARTBASE_BASE_ARRAY_SLICE_H_ |