Index()

size_t Spices::MemoryPool::Index ( size_t size )

static

Determine which freelist should process the memory block with given bytes.

Parameters

[in]

size

memory block bytes.

Returns

Returns index of freelist.

Definition at line 88 of file MemoryPool.cpp.

    {
        auto _index = [&](size_t bytes, size_t align_shift) -> size_t
        {
            return ((bytes + (1 << align_shift) - 1) >> align_shift) - 1;
        };
 
        static constexpr int group_array[4] = { 16, 56, 56, 56 };
 
        if (size <= 128)
        {
            return _index(size, 3);
        }
        else if (size <= 1024)
        {
            return _index(size - 128, 4) + 
                group_array[0];
        }
        else if (size <= static_cast<size_t>(8 * 1024))
        {
            return _index(size - 1024, 7) + 
                group_array[1] + 
                group_array[0];
        }
        else if (size <= static_cast<size_t>(64 * 1024))
        {
            return _index(size - static_cast<size_t>(8 * 1024), 10) + 
                group_array[2] + 
                group_array[1] + 
                group_array[0];
        }
        else if (size <= static_cast<size_t>(256 * 1024))
        {
            return _index(size - static_cast<size_t>(64 * 1024), 13) + 
                group_array[3] + 
                group_array[2] + 
                group_array[1] + 
                group_array[0];
        }
        else
        {
            assert(false);
            return -1;
        }
    }