| // Copyright 2025 Google LLC |
| // |
| // 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 SOURCE_UTIL_SPAN_H_ |
| #define SOURCE_UTIL_SPAN_H_ |
| |
| #include <cstddef> |
| #include <iterator> |
| #include <type_traits> |
| |
| namespace spvtools { |
| namespace utils { |
| |
| // Implement a subset of the C++20 std::span, using at most C++17 functionality. |
| // Replace this when SPIRV-Tools can use C++20. |
| template <class T> |
| class Span { |
| public: |
| using element_type = T; |
| using value_type = std::remove_cv_t<T>; |
| using size_type = std::size_t; |
| using difference_type = std::ptrdiff_t; |
| using pointer = T*; |
| using const_pointer = const T*; |
| using reference = T&; |
| using const_reference = const T&; |
| using iterator = T*; |
| using const_iterator = const T*; |
| |
| Span() {} |
| Span(iterator first, size_type count) : first_(first), count_(count) {} |
| |
| iterator begin() const { return first_; } |
| iterator end() const { return first_ ? first_ + count_ : nullptr; } |
| const_iterator cbegin() const { return first_; } |
| const_iterator cend() const { return first_ ? first_ + count_ : nullptr; } |
| |
| size_type size() const { return count_; } |
| size_type size_bytes() const { return count_ * sizeof(T); } |
| bool empty() const { return first_ == nullptr || count_ == 0; } |
| |
| reference front() const { return *first_; } |
| reference back() const { return *(first_ + count_ - 1); } |
| pointer data() const { return first_; } |
| reference operator[](size_type idx) const { return first_[idx]; } |
| Span<T> subspan(size_type offset) const { |
| if (count_ > offset) { |
| return Span(first_ + offset, count_ - offset); |
| } |
| return Span<T>(); |
| } |
| |
| private: |
| T* first_ = nullptr; |
| size_type count_ = 0; |
| }; |
| |
| } // namespace utils |
| } // namespace spvtools |
| |
| #endif // SOURCE_UTIL_SPAN_H_ |