poly_ptr_ptr.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once

#include <stdexcept>
#include <cstdlib>

namespace mrpt
{
namespace utils
{
/** \addtogroup stlext_grp
  * @{ */

/** Wrapper to a clone smart pointer to polymorphic classes, capable of handling
* copy operator, etc. making deep copies.
* Example use: `poly_ptr_ptr<mrpt::poses::CPosePDF::Ptr>`
* \sa copy_ptr<T>
*/
template <typename T>
class poly_ptr_ptr
{
   public:
        /** Ctor from a smart pointer; makes deep copy. */
        poly_ptr_ptr(const T& ptr)
        {
                m_smartptr.reset(dynamic_cast<typename T::element_type*>(ptr->clone()));
        }
        /** Default ctor; init to nullptr. */
        poly_ptr_ptr() {}
        /** copy ctor: makes a copy of the object via `clone()` */
        poly_ptr_ptr(const poly_ptr_ptr<T>& o)
        {
                m_smartptr.reset(
                        dynamic_cast<typename T::element_type*>(o.m_smartptr->clone()));
        }
        poly_ptr_ptr<T>& operator=(const poly_ptr_ptr<T>& o)
        {
                if (this == &o) return *this;
                m_smartptr.reset(
                        dynamic_cast<typename T::element_type*>(o.m_smartptr->clone()));
                return *this;
        }
        poly_ptr_ptr<T>& operator=(const T& o_ptr)
        {
                m_smartptr.reset(
                        dynamic_cast<typename T::element_type*>(o_ptr->clone()));
                return *this;
        }
        /** move ctor */
        poly_ptr_ptr(poly_ptr_ptr&& o)
        {
                m_smartptr = o.m_smartptr;
                o.m_smartptr.reset();
        }
        /** move operator */
        poly_ptr_ptr<T>& operator=(poly_ptr_ptr<T>&& o)
        {
                if (this == &o) return *this;
                m_smartptr = o.m_smartptr;
                o.m_smartptr.reset();
                return *this;
        }
        ~poly_ptr_ptr() {}
        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*(void)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
}  // End of namespace
}  // End of namespace