| // Copyright 2023 The Dawn & Tint Authors |
| // |
| // 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. |
| // |
| // 3. Neither the name of the copyright holder nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT HOLDER 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. |
| |
| #ifndef SRC_DAWN_COMMON_ENUMERATOR_H_ |
| #define SRC_DAWN_COMMON_ENUMERATOR_H_ |
| |
| #include <type_traits> |
| #include <utility> |
| |
| namespace dawn { |
| |
| // An iterator over a range that gives both the index and the value. It can be used like so: |
| // |
| // ityp::span<Index, Value> span = ...; |
| // for (auto [i, value] : Enumerate(span)) { |
| // // Use i that's of type Index. |
| // // Use value that's of type Value&. |
| // } |
| template <typename Index, typename Value> |
| class EnumerateRange final { |
| public: |
| EnumerateRange(Index size, Value* begin) : mSize(size), mBegin(begin) {} |
| |
| class Iterator final { |
| public: |
| Iterator(Index index, Value* value) : mIndex(index), mValue(value) {} |
| bool operator==(const Iterator& other) const { return other.mIndex == mIndex; } |
| bool operator!=(const Iterator& other) const { return !(*this == other); } |
| Iterator& operator++() { |
| mIndex++; |
| mValue++; |
| return *this; |
| } |
| std::pair<Index, Value&> operator*() const { return {mIndex, *mValue}; } |
| |
| private: |
| Index mIndex; |
| Value* mValue; |
| }; |
| |
| Iterator begin() const { return Iterator(Index{}, mBegin); } |
| // Note that iterator comparison only uses mIndex, so we can save the computation of mValue for |
| // the end() iterator. |
| Iterator end() const { return Iterator(mSize, nullptr); } |
| |
| private: |
| Index mSize; |
| Value* mBegin; |
| }; |
| |
| template <typename T, |
| typename Index = decltype(std::declval<T>().size()), |
| typename Value = std::remove_pointer_t<decltype(std::declval<T>().data())>> |
| EnumerateRange<Index, Value> Enumerate(T& v) { |
| return {v.size(), v.data()}; |
| } |
| } // namespace dawn |
| |
| #endif // SRC_DAWN_COMMON_ENUMERATOR_H_ |