Class TMaybeOwnedBitMap

catboost/python-package/catboost/arrow.cpp:240–306

    class TMaybeOwnedBitMap {
    public:
        // non-owning
        explicit TMaybeOwnedBitMap(
            const ui8* data,
            ui32 beginOffsetInData,
            ui32 size,
            TIntrusivePtr<IResourceHolder> resourceHolder
        )
            : Data_(
                TMaybeOwningConstArrayHolder<const ui8>::CreateOwning(
                    {
                        data + beginOffsetInData / CHAR_BIT,
                        CeilDiv<size_t>(beginOffsetInData % CHAR_BIT + size, CHAR_BIT)
                    },
                    std::move(resourceHolder)
                )
            )
            , BeginOffsetInData_(beginOffsetInData % CHAR_BIT)
            , Size_(size)
        {
        }

        int operator&(IBinSaver& binSaver) {
            binSaver.Add(0, &Data_);
            binSaver.Add(1, &BeginOffsetInData_);
            binSaver.Add(1, &Size_);
            return 0;
        }

        bool operator==(const TMaybeOwnedBitMap& rhs) const {
            if (Size_ != rhs.Size_) {
                return false;
            }
            // could be optimized for some cases but this operation is not performance-critical right now
            for (auto i : xrange(Size_)) {
                if ((*this)[i] != rhs[i]) {
                    return false;
                }
            }
            return true;
        }

        bool operator[](size_t idx) const {
            Y_ASSERT(idx < Size_);
            size_t offsetInData = BeginOffsetInData_ + idx;
            return (Data_[offsetInData / CHAR_BIT] >> (offsetInData % CHAR_BIT)) & 1;
        }

        ui32 GetSize() const {
            return Size_;
        }

        TMaybeOwnedBitMap Slice(size_t offset, size_t size) const {
            return TMaybeOwnedBitMap(
                Data_.data(),
                BeginOffsetInData_ + offset,
                size,