src/dawn/wire/BufferConsumer_impl.h

// Copyright 2021 The Dawn & Tint Authors
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#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/439062058): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#ifndef SRC_DAWN_WIRE_BUFFERCONSUMER_IMPL_H_
#define SRC_DAWN_WIRE_BUFFERCONSUMER_IMPL_H_

#include <limits>
#include <type_traits>

#include "dawn/wire/BufferConsumer.h"

namespace dawn::wire {

template <typename BufferT>
template <typename T>
WireResult BufferConsumer<BufferT>::Peek(T** data) {
    if (sizeof(T) > mSize) {
        return WireResult::FatalError;
    }

    *data = reinterpret_cast<T*>(mBuffer.get());
    return WireResult::Success;
}

template <typename BufferT>
template <typename T>
WireResult BufferConsumer<BufferT>::Next(T** data) {
    constexpr size_t kSize = WireAlignSizeof<T>();
    if (kSize > mSize) {
        return WireResult::FatalError;
    }

    *data = reinterpret_cast<T*>(mBuffer.get());
    mBuffer += kSize;
    mSize -= kSize;
    return WireResult::Success;
}

template <typename BufferT>
template <typename T, typename N>
WireResult BufferConsumer<BufferT>::NextN(N count, T** data) {
    static_assert(std::is_unsigned<N>::value, "|count| argument of NextN must be unsigned.");

    // If size is zero then it indicates an overflow.
    auto size = WireAlignSizeofN<T>(count);
    if (!size || *size > mSize) {
        return WireResult::FatalError;
    }

    *data = reinterpret_cast<T*>(mBuffer.get());
    mBuffer += *size;
    mSize -= *size;
    return WireResult::Success;
}

}  // namespace dawn::wire

#endif  // SRC_DAWN_WIRE_BUFFERCONSUMER_IMPL_H_