| // Copyright 2021 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_WIRE_BUFFERCONSUMER_H_ |
| #define SRC_DAWN_WIRE_BUFFERCONSUMER_H_ |
| |
| #include <cstddef> |
| |
| #include "dawn/common/Constants.h" |
| #include "dawn/common/Math.h" |
| #include "dawn/wire/WireResult.h" |
| |
| namespace dawn::wire { |
| |
| // Wire specific alignment helpers. |
| template <typename T> |
| constexpr size_t WireAlignSizeof() { |
| return AlignSizeof<T, kWireBufferAlignment>(); |
| } |
| template <typename T> |
| std::optional<size_t> WireAlignSizeofN(size_t n) { |
| return AlignSizeofN<T, kWireBufferAlignment>(n); |
| } |
| |
| // BufferConsumer is a utility class that allows reading bytes from a buffer |
| // while simultaneously decrementing the amount of remaining space by exactly |
| // the amount read. It helps prevent bugs where incrementing a pointer and |
| // decrementing a size value are not kept in sync. |
| // BufferConsumer also contains bounds checks to prevent reading out-of-bounds. |
| template <typename BufferT> |
| class BufferConsumer { |
| static_assert(sizeof(BufferT) == 1, |
| "BufferT must be 1-byte, but may have const/volatile qualifiers."); |
| |
| public: |
| BufferConsumer(BufferT* buffer, size_t size) : mBuffer(buffer), mSize(size) {} |
| |
| BufferT* Buffer() const { return mBuffer; } |
| size_t AvailableSize() const { return mSize; } |
| |
| protected: |
| template <typename T, typename N> |
| WireResult NextN(N count, T** data); |
| |
| template <typename T> |
| WireResult Next(T** data); |
| |
| template <typename T> |
| WireResult Peek(T** data); |
| |
| private: |
| BufferT* mBuffer; |
| size_t mSize; |
| }; |
| |
| class SerializeBuffer : public BufferConsumer<char> { |
| public: |
| using BufferConsumer::BufferConsumer; |
| using BufferConsumer::Next; |
| using BufferConsumer::NextN; |
| }; |
| |
| class DeserializeBuffer : public BufferConsumer<const volatile char> { |
| public: |
| using BufferConsumer::BufferConsumer; |
| using BufferConsumer::Peek; |
| |
| template <typename T, typename N> |
| WireResult ReadN(N count, const volatile T** data) { |
| return NextN(count, data); |
| } |
| |
| template <typename T> |
| WireResult Read(const volatile T** data) { |
| return Next(data); |
| } |
| }; |
| |
| } // namespace dawn::wire |
| |
| #endif // SRC_DAWN_WIRE_BUFFERCONSUMER_H_ |