| // Copyright 2021 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_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_ |