Class TFileMappedArray

util/system/filemap.h:187–289

template <class T>
class TFileMappedArray {
private:
    const T* Ptr_;
    const T* End_;
    size_t Size_;
    char DummyData_[sizeof(T) + PLATFORM_DATA_ALIGN];
    mutable THolder<T, TDestructor> Dummy_;
    THolder<TFileMap> DataHolder_;

public:
    TFileMappedArray()
        : Ptr_(nullptr)
        , End_(nullptr)
        , Size_(0)
    {
    }
    ~TFileMappedArray() {
        Ptr_ = nullptr;
        End_ = nullptr;
    }
    void Init(const char* name) {
        DataHolder_.Reset(new TFileMap(name));
        DoInit(name);
    }
    void Init(const TFileMap& fileMap) {
        DataHolder_.Reset(new TFileMap(fileMap));
        DoInit(fileMap.GetFile().GetName());
    }
    void Term() {
        DataHolder_.Destroy();
        Ptr_ = nullptr;
        Size_ = 0;
        End_ = nullptr;
    }
    void Precharge() {
        DataHolder_->Precharge();
    }
    const T& operator[](size_t pos) const {
        Y_ASSERT(pos < size());
        return Ptr_[pos];
    }
    /// for STL compatibility only, Size() usage is recommended
    size_t size() const {
        return Size_;
    }
    size_t Size() const {
        return Size_;
    }
    const T& GetAt(size_t pos) const {
        if (pos < Size_) {
            return Ptr_[pos];
        }
        return Dummy();
    }
    void SetDummy(const T& n_Dummy) {
        Dummy_.Destroy();
        Dummy_.Reset(new (DummyData()) T(n_Dummy));
    }