| // Copyright 2020 The Dawn 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 |
| // |
| // 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 SRC_DAWN_COMMON_ITYP_SPAN_H_ |
| #define SRC_DAWN_COMMON_ITYP_SPAN_H_ |
| |
| #include <type_traits> |
| |
| #include "dawn/common/TypedInteger.h" |
| #include "dawn/common/UnderlyingType.h" |
| |
| namespace dawn::ityp { |
| |
| // ityp::span is a helper class that wraps an unowned packed array of type |Value|. |
| // It stores the size and pointer to first element. It has the restriction that |
| // indices must be a particular type |Index|. This provides a type-safe way to index |
| // raw pointers. |
| template <typename Index, typename Value> |
| class span { |
| using I = UnderlyingType<Index>; |
| |
| public: |
| constexpr span() : mData(nullptr), mSize(0) {} |
| constexpr span(Value* data, Index size) : mData(data), mSize(size) {} |
| |
| constexpr Value& operator[](Index i) const { |
| ASSERT(i < mSize); |
| return mData[static_cast<I>(i)]; |
| } |
| |
| Value* data() noexcept { return mData; } |
| |
| const Value* data() const noexcept { return mData; } |
| |
| Value* begin() noexcept { return mData; } |
| |
| const Value* begin() const noexcept { return mData; } |
| |
| Value* end() noexcept { return mData + static_cast<I>(mSize); } |
| |
| const Value* end() const noexcept { return mData + static_cast<I>(mSize); } |
| |
| Value& front() { |
| ASSERT(mData != nullptr); |
| ASSERT(static_cast<I>(mSize) >= 0); |
| return *mData; |
| } |
| |
| const Value& front() const { |
| ASSERT(mData != nullptr); |
| ASSERT(static_cast<I>(mSize) >= 0); |
| return *mData; |
| } |
| |
| Value& back() { |
| ASSERT(mData != nullptr); |
| ASSERT(static_cast<I>(mSize) >= 0); |
| return *(mData + static_cast<I>(mSize) - 1); |
| } |
| |
| const Value& back() const { |
| ASSERT(mData != nullptr); |
| ASSERT(static_cast<I>(mSize) >= 0); |
| return *(mData + static_cast<I>(mSize) - 1); |
| } |
| |
| Index size() const { return mSize; } |
| |
| private: |
| Value* mData; |
| Index mSize; |
| }; |
| |
| } // namespace dawn::ityp |
| |
| #endif // SRC_DAWN_COMMON_ITYP_SPAN_H_ |