src/dawn/wire/WireDeserializeAllocator.cpp

// Copyright 2019 The Dawn & Tint Authors
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#include "dawn/wire/WireDeserializeAllocator.h"

#include <algorithm>

namespace dawn::wire {
WireDeserializeAllocator::WireDeserializeAllocator() {
    Reset();
}

WireDeserializeAllocator::~WireDeserializeAllocator() {
    Reset();
}

void* WireDeserializeAllocator::GetSpace(size_t size) {
    // Return space in the current buffer if possible first.
    if (mRemainingSize >= size) {
        char* buffer = mCurrentBuffer;
        mCurrentBuffer += size;
        mRemainingSize -= size;
        return buffer;
    }

    // Otherwise allocate a new buffer and try again.
    size_t allocationSize = std::max(size, size_t(2048));
    char* allocation = static_cast<char*>(malloc(allocationSize));
    if (allocation == nullptr) {
        return nullptr;
    }

    mAllocations.push_back(allocation);
    mCurrentBuffer = allocation;
    mRemainingSize = allocationSize;
    return GetSpace(size);
}

void WireDeserializeAllocator::Reset() {
    // The initial buffer is the inline buffer so that some allocations can be skipped
    mCurrentBuffer = mStaticBuffer;
    mRemainingSize = sizeof(mStaticBuffer);

    for (auto& allocation : mAllocations) {
        free(allocation.ExtractAsDangling());
    }
    mAllocations.clear();
}
}  // namespace dawn::wire