UniqueIdentifier.hpp

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/*
 *  Copyright 2019-2021 Diligent Graphics LLC
 *  Copyright 2015-2019 Egor Yusov
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */
 
#pragma once
 
#include "../../Primitives/interface/BasicTypes.h"
#include "../../Platforms/interface/Atomics.hpp"
 
namespace Diligent
{
 
using UniqueIdentifier = Int32;
 
// Template switch is used to have distinct counters
// for unrelated groups of objects
template <typename ObjectsClass>
class UniqueIdHelper
{
public:
    UniqueIdHelper() noexcept {}
 
    // clang-format off
    UniqueIdHelper             (const UniqueIdHelper&) = delete;
    UniqueIdHelper& operator = (const UniqueIdHelper&) = delete;
    // clang-format on
 
    UniqueIdHelper(UniqueIdHelper&& RHS) noexcept :
        m_ID{RHS.m_ID}
    {
        RHS.m_ID = 0;
    }
 
    UniqueIdHelper& operator=(UniqueIdHelper&& RHS) noexcept
    {
        m_ID     = RHS.m_ID;
        RHS.m_ID = 0;
        return *this;
    }
 
    UniqueIdentifier GetID() const noexcept
    {
        if (m_ID == 0)
        {
            static Atomics::AtomicLong GlobalCounter; // = 0 causes gcc error
            m_ID = static_cast<UniqueIdentifier>(Atomics::AtomicIncrement(GlobalCounter));
        }
        return m_ID;
    }
 
private:
    mutable UniqueIdentifier m_ID = 0;
};
 
} // namespace Diligent