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// 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"
#include "partition_alloc/pointers/raw_ptr.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:
raw_ptr<BufferT, AllowPtrArithmetic> 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_