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281 lines
11 KiB
C++
281 lines
11 KiB
C++
///******************************************************************************
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//The MIT License(MIT)
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//
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//Embedded Template Library.
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//https://github.com/ETLCPP/etl
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//https://www.etlcpp.com
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//
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//Copyright(c) 2021 jwellbelove
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//
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//Permission is hereby granted, free of charge, to any person obtaining a copy
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//of this software and associated documentation files(the "Software"), to deal
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//in the Software without restriction, including without limitation the rights
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//to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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//copies of the Software, and to permit persons to whom the Software is
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//furnished to do so, subject to the following conditions :
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//
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//The above copyright notice and this permission notice shall be included in all
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//copies or substantial portions of the Software.
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//
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//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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//SOFTWARE.
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//******************************************************************************/
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#ifndef ETL_REFERENCE_COUNTED_OBJECT_INCLUDED
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#define ETL_REFERENCE_COUNTED_OBJECT_INCLUDED
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#include <stdint.h>
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#include "platform.h"
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#include "atomic.h"
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namespace etl
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{
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//***************************************************************************
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/// The base of all reference counters.
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//***************************************************************************
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class ireference_counter
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{
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public:
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virtual ~ireference_counter() {};
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virtual void set_reference_count(int32_t value) = 0;
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virtual void increment_reference_count() = 0;
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ETL_NODISCARD virtual int32_t decrement_reference_count() = 0;
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ETL_NODISCARD virtual int32_t get_reference_count() const = 0;
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};
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//***************************************************************************
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/// A specific type of reference counter.
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//***************************************************************************
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template <typename TCounter>
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class reference_counter : public ireference_counter
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{
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public:
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//***************************************************************************
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/// Constructor.
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//***************************************************************************
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reference_counter()
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: reference_count(0)
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{
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}
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//***************************************************************************
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/// Set the reference count.
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//***************************************************************************
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virtual void set_reference_count(int32_t value) ETL_OVERRIDE
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{
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reference_count = value;
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}
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//***************************************************************************
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/// Increment the reference count.
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//***************************************************************************
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virtual void increment_reference_count() ETL_OVERRIDE
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{
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++reference_count;
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}
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//***************************************************************************
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/// Decrement the reference count.
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//***************************************************************************
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ETL_NODISCARD virtual int32_t decrement_reference_count() ETL_OVERRIDE
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{
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assert(reference_count > 0);
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return int32_t(--reference_count);
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}
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//***************************************************************************
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/// Get the current reference count.
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//***************************************************************************
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ETL_NODISCARD virtual int32_t get_reference_count() const ETL_OVERRIDE
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{
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return int32_t(reference_count);
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}
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private:
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TCounter reference_count; // The reference count object.
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};
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//***************************************************************************
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/// A null reference counter.
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/// Always returns the reference count as 1, for persistent objects.
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//***************************************************************************
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class null_reference_counter : public ireference_counter
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{
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public:
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//***************************************************************************
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/// Set the reference count.
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//***************************************************************************
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virtual void set_reference_count(int32_t value) ETL_OVERRIDE
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{
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}
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//***************************************************************************
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/// Increment the reference count.
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//***************************************************************************
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virtual void increment_reference_count() ETL_OVERRIDE
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{
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}
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//***************************************************************************
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/// Decrement the reference count.
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//***************************************************************************
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ETL_NODISCARD virtual int32_t decrement_reference_count() ETL_OVERRIDE
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{
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return int32_t(1);
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}
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//***************************************************************************
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/// Get the current reference count.
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//***************************************************************************
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ETL_NODISCARD virtual int32_t get_reference_count() const ETL_OVERRIDE
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{
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return int32_t(1);
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}
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};
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//***************************************************************************
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/// Base for all reference counted objects.
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//***************************************************************************
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class ireference_counted_object
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{
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public:
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virtual ~ireference_counted_object() {}
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ETL_NODISCARD virtual ireference_counter& get_reference_counter() = 0;
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ETL_NODISCARD virtual const ireference_counter& get_reference_counter() const = 0;
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};
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//***************************************************************************
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/// Class for creating reference counted objects.
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/// \tparam TObject The type to be reference counted.
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/// \tparam TCounter The type to use as the counter.
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//***************************************************************************
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template <typename TObject, typename TCounter>
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class reference_counted_object : public etl::ireference_counted_object
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{
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public:
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typedef TObject value_type;
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typedef TCounter counter_type;
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//***************************************************************************
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/// Constructor.
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//***************************************************************************
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reference_counted_object(const TObject& object_)
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: object(object_)
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{
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}
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//***************************************************************************
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/// Get a const reference to the counted object.
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//***************************************************************************
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ETL_NODISCARD const value_type& get_object() const
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{
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return object;
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}
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//***************************************************************************
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/// Get a reference to the reference counter.
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//***************************************************************************
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ETL_NODISCARD virtual ireference_counter& get_reference_counter() ETL_OVERRIDE
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{
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return reference_counter;
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}
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//***************************************************************************
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/// Get a const reference to the reference counter.
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//***************************************************************************
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ETL_NODISCARD virtual const ireference_counter& get_reference_counter() const ETL_OVERRIDE
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{
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return reference_counter;
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}
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private:
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// This class must not be default contructed, copy constructed or assigned.
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reference_counted_object() ETL_DELETE;
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reference_counted_object(const reference_counted_object&) ETL_DELETE;
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reference_counted_object& operator =(const reference_counted_object&) ETL_DELETE;
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const TObject object; ///< The object being reference counted.
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etl::reference_counter<TCounter> reference_counter; ///< The reference counter.
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};
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//***************************************************************************
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/// Persistent message type.
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/// The message type will always have a reference count of 1.
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/// \tparam TObject The type stored in the object.
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//***************************************************************************
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template <typename TObject>
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class persistent_object : public etl::ireference_counted_object
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{
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public:
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typedef TObject value_type;
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//***************************************************************************
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/// Constructor.
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//***************************************************************************
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persistent_object(const TObject& object_)
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: object(object_)
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{
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}
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//***************************************************************************
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/// Get a const reference to the counted object.
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//***************************************************************************
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ETL_NODISCARD const value_type& get_object() const
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{
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return object;
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}
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//***************************************************************************
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/// Get a reference to the reference counter.
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//***************************************************************************
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ETL_NODISCARD virtual ireference_counter& get_reference_counter() ETL_OVERRIDE
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{
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return reference_counter;
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}
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//***************************************************************************
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/// Get a const reference to the reference counter.
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//***************************************************************************
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ETL_NODISCARD virtual const ireference_counter& get_reference_counter() const ETL_OVERRIDE
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{
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return reference_counter;
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}
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private:
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// This class must not be default contructed, copy constructed or assigned.
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persistent_object() ETL_DELETE;
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persistent_object(const persistent_object&) ETL_DELETE;
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persistent_object& operator =(const persistent_object&) ETL_DELETE;
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TObject object; ///< The object being reference counted.
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etl::null_reference_counter reference_counter; ///< The reference counter.
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};
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#if ETL_CPP11_SUPPORTED && ETL_HAS_ATOMIC
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//***************************************************************************
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/// Class for creating reference counted objects using an atomic counter.
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/// \tparam TObject The type to be reference counted.
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//***************************************************************************
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template <typename TObject>
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using atomic_counted_object = etl::reference_counted_object<TObject, etl::atomic_int32_t>;
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#endif
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}
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#endif
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