/*
 * Copyright (C) 2015 by Multi-Tech Systems
 *
 * This file is part of libmts.
 *
 * libmts is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * libmts is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libmts.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/*! \file   MTS_SharedPtr.h
 \brief  A shared pointer template
 \date   15JUN11
 \author Sean Godinez

 A shared pointer template
 */

#ifndef _MTS_SHAREDPTR_H
#define _MTS_SHAREDPTR_H

namespace MTS {

    //! A shared pointer
    /*!
     A shared pointer keeps track of references and
     cleans up when the reference count reaches zero
     */
    template<class T> class SharedPtr {

        public:

            enum MallocType {
                SINGLE, ARRAY
            };

            explicit SharedPtr(T* ptr = 0, MallocType type = SINGLE); //!< Explicitly Constructs the SharedPtr to reference ptr
            SharedPtr(const SharedPtr<T>& other); //!< Constructs from another shared pointer, increasing reference count
            ~SharedPtr();				   //!< Destructs the AutoPtr deleting T

            SharedPtr<T>& operator=(const SharedPtr<T>& other);	//!< Releases *this and shares other's T

            T& operator*() const;						//!< Returns T
            T* operator->() const;					    //!< Returns address of T
            T& operator[](const uint32_t& index) const; //!< Returns T at index
            T* get() const;							    //!< Returns address of T

            bool isNull() const;			            //!< Returns true if pointer is NULL
            bool isShared() const;                      //!< Returns true if reference count is greater than 1
            int count() const;				            //!< Returns number of references

        private:

            T* m_pObj;								    //!< Reference to class T
            int* m_pReferences;				            //!< Reference to reference count
            MallocType m_eType;	                        //!< Describes memory allocated as a single T or block of Ts

            void release();
    };

    template<class T> SharedPtr<T>::SharedPtr(T* ptr, MallocType type)
    : m_pObj(ptr), m_pReferences(new int(1)), m_eType(type) {
    }

    template<class T> SharedPtr<T>::SharedPtr(const SharedPtr<T>& other)
    : m_pObj(other.m_pObj), m_pReferences(other.m_pReferences), m_eType(other.m_eType) {
        *(m_pReferences) += 1;
    }

    template<class T> SharedPtr<T>::~SharedPtr() {
        release();
    }

    template<class T> SharedPtr<T>& SharedPtr<T>::operator=(
    const SharedPtr<T>& other) {
        if (&other != this) {
            release();
            this->m_pObj = other.m_pObj;
            this->m_pReferences = other.m_pReferences;
            this->m_eType = other.m_eType;
            (*m_pReferences) += 1;
        }
        return *this;
    }

    template<class T> T& SharedPtr<T>::operator*() const {
        return *m_pObj;
    }

    template<class T> T* SharedPtr<T>::operator->() const {
        return m_pObj;
    }

    template<class T> T& SharedPtr<T>::operator[](const uint32_t& index) const {
        return m_pObj[index];
    }

    template<class T> T* SharedPtr<T>::get() const {
        return m_pObj;
    }

    template<class T> bool SharedPtr<T>::isNull() const {
        return (m_pObj == 0);
    }

    template<class T> bool SharedPtr<T>::isShared() const {
        return ((*m_pReferences) > 1);
    }

    template<class T> int SharedPtr<T>::count() const {
        return (*m_pReferences);
    }

    template<class T> void SharedPtr<T>::release() {
        (*m_pReferences) -= 1;
        if ((*m_pReferences) == 0) {
            if (m_eType == SINGLE) {
                delete m_pObj;
            } else {
                delete[] m_pObj;
            }
            delete m_pReferences;
        }
    }
}

#endif