///////////////////////////////////////////////////////////////////////////////
//
// File: ConsistentObjectAccess.hpp
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
// Department of Aeronautics, Imperial College London (UK), and Scientific
// Computing and Imaging Institute, University of Utah (USA).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
// Description: A wrapper around objects or pointers to objects which give
// the same interface for both types (i.e., -> will work for both).
//
///////////////////////////////////////////////////////////////////////////////

#ifndef NEKTAR_LIB_UTILITIES_BASIC_UTILS_CONSISTENT_ACCESS_OBJECT_HPP
#define NEKTAR_LIB_UTILITIES_BASIC_UTILS_CONSISTENT_ACCESS_OBJECT_HPP

#include <LibUtilities/BasicUtils/ErrorUtil.hpp>
#include <memory>

namespace Nektar
{
template <typename DataType> struct ConsistentObjectAccess
{
    static DataType &reference(DataType &o)
    {
        return o;
    }
    static const DataType &const_reference(const DataType &o)
    {
        return o;
    }
    static DataType *pointer(DataType &o)
    {
        return &o;
    }
    static const DataType *const_pointer(const DataType &o)
    {
        return &o;
    }

    static bool ReferencesObject([[maybe_unused]] const DataType &o)
    {
        return true;
    }
};

template <typename DataType> struct ConsistentObjectAccess<DataType *>
{
    static const DataType &const_reference(DataType *o)
    {
        ASSERTL1(o != nullptr, "Can't dereference null pointer.");
        return *o;
    }
    static const DataType *const_pointer(DataType *o)
    {
        return o;
    }
    static bool ReferencesObject(DataType *o)
    {
        return o != nullptr;
    }

    static DataType &reference(DataType *o)
    {
        ASSERTL1(o != nullptr, "Can't dereference null pointer.");
        return *o;
    }
    static DataType *pointer(DataType *o)
    {
        return o;
    }
};

template <typename DataType>
struct ConsistentObjectAccess<std::shared_ptr<DataType>>
{
    static const DataType &const_reference(const std::shared_ptr<DataType> &o)
    {
        ASSERTL1(o, "Can't dereference null pointer.");
        return *o;
    }
    static const DataType *const_pointer(const std::shared_ptr<DataType> &o)
    {
        return o.get();
    }
    static DataType &reference(const std::shared_ptr<DataType> &o)
    {
        ASSERTL1(o, "Can't dereference null pointer.");
        return *o;
    }
    static DataType *pointer(const std::shared_ptr<DataType> &o)
    {
        return o.get();
    }
    static bool ReferencesObject(const std::shared_ptr<DataType> &o)
    {
        return o.get();
    }
};
} // namespace Nektar

#endif // NEKTAR_LIB_UTILITIES_BASIC_UTILS_CONSISTENT_ACCESS_OBJECT_HPP
