deepcopy_poly_ptr.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <cstdlib>
#include <stdexcept>

namespace mrpt::containers
{
/** \addtogroup mrpt_containers_grp
 * @{ */

/** Wrapper to a std::shared_ptr<>, adding deep-copy semantics to copy ctor and
 * copy operator, suitable for polymorphic classes with a `clone()` method.
 * Example use: `deepcopy_poly_ptr<mrpt::poses::CPosePDF::Ptr>`
 * \sa for non-virtual classes, see copy_ptr<T>
 */
template <typename T>
class deepcopy_poly_ptr
{
   public:
    /** Ctor from a smart pointer; makes deep copy. */
    deepcopy_poly_ptr(const T& ptr)
    {
        m_smartptr.reset(dynamic_cast<typename T::element_type*>(ptr->clone()));
    }
    /** Default ctor; init to nullptr. */
    deepcopy_poly_ptr() = default;
    /** copy ctor: makes a copy of the object via `clone()` */
    deepcopy_poly_ptr(const deepcopy_poly_ptr<T>& o)
    {
        m_smartptr.reset(
            dynamic_cast<typename T::element_type*>(o.m_smartptr->clone()));
    }
    deepcopy_poly_ptr<T>& operator=(const deepcopy_poly_ptr<T>& o)
    {
        if (this == &o) return *this;
        m_smartptr.reset(
            dynamic_cast<typename T::element_type*>(o.m_smartptr->clone()));
        return *this;
    }
    deepcopy_poly_ptr<T>& operator=(const T& o_ptr)
    {
        m_smartptr.reset(
            dynamic_cast<typename T::element_type*>(o_ptr->clone()));
        return *this;
    }
    /** move ctor */
    deepcopy_poly_ptr(deepcopy_poly_ptr&& o)
    {
        m_smartptr = o.m_smartptr;
        o.m_smartptr.reset();
    }
    /** move operator */
    deepcopy_poly_ptr<T>& operator=(deepcopy_poly_ptr<T>&& o)
    {
        if (this == &o) return *this;
        m_smartptr = o.m_smartptr;
        o.m_smartptr.reset();
        return *this;
    }
    ~deepcopy_poly_ptr() = default;
    typename T::element_type* get()
    {
        if (m_smartptr)
            return m_smartptr.get();
        else
            throw std::runtime_error("dereferencing nullptr poly_ptr");
    }
    const typename T::element_type* get() const
    {
        if (m_smartptr)
            return m_smartptr.get();
        else
            throw std::runtime_error("dereferencing nullptr poly_ptr");
    }

    typename T::element_type* operator->() { return get(); }
    const typename T::element_type* operator->() const { return get(); }
    typename T::element_type& operator*(void) { return *get(); }
    const typename T::element_type& operator*() const { return *get(); }
    operator bool() const { return m_smartptr ? true : false; }
    bool operator!(void) const { return m_smartptr ? false : true; }
    const T& get_ptr() const { return m_smartptr; }
    T& get_ptr() { return m_smartptr; }
    void reset() { m_smartptr.reset(); }

   private:
    T m_smartptr;
};

/** @} */  // end of grouping
}  // namespace mrpt::containers