Reference counting helpers - Base class, partial pointers
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#ifndef _H_EBCL_EXTERNALS
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#define _H_EBCL_EXTERNALS
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#include <atomic>
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#include <cstddef>
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#include <cstdint>
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#include <cstring>
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108
include/ebcl/RefCount.hh
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108
include/ebcl/RefCount.hh
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/******************************************************************************/
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/* REFERENCE-COUNTING HELPERS *************************************************/
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/******************************************************************************/
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#ifndef _H_EBCL_REFCOUNT
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#define _H_EBCL_REFCOUNT
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#include <ebcl/Utilities.hh>
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namespace ebcl {
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// A base class and pointer type that can be used to implement classes which
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// use in-instance reference counters.
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/*= REFERENCE-COUNTED INSTANCES ==============================================*/
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// Base class containing the reference counter. It may be an atomic, or it
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// may be a simple integer.
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template< bool UseAtomic = false >
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class T_ReferenceCountedClass
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{
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public:
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// Is it atomic ?
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static const bool UsingAtomic = UseAtomic;
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// Reference counter type
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using T_ReferenceCounter = std::conditional_t<
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UseAtomic , std::atomic< uint32_t > , uint32_t
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>;
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// Reference-counting pointers can access the counter
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template< typename > friend class T_RcPtr;
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private:
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T_ReferenceCounter referenceCounter_;
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// Add a reference to the counter
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void increaseReferences_( ) noexcept;
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// Remove a reference from the counter, returning true if the instance
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// is no longer referenced.
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bool decreaseReferences_( ) noexcept;
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protected:
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T_ReferenceCountedClass( ) noexcept;
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};
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// Shortcuts
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using T_AtomicRcClass = T_ReferenceCountedClass< true >;
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using T_SimpleRcClass = T_ReferenceCountedClass< false >;
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/*= REFERENCE-COUNTING POINTERS ==============================================*/
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// Pointers that use T_ReferenceCountedClass in order to track the reference
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// counts of the instances it manages.
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template< typename Type >
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class T_RcPtr
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{
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static_assert( MetaOr< std::is_base_of< T_AtomicRcClass , Type > ,
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std::is_base_of< T_SimpleRcClass , Type > >::value ,
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"type does not include a reference counter" );
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public:
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// Target type
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using T_Target = Type;
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// Pointer type
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using T_Self = T_RcPtr< Type >;
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// Base reference counting class
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using T_RcClass = std::conditional_t<
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std::is_base_of< T_AtomicRcClass , Type >::value ,
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T_AtomicRcClass , T_SimpleRcClass
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>;
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private:
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T_Target* target_;
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public:
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// ---------------------------------------------------------------------
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T_RcPtr( ) noexcept;
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~T_RcPtr( ) noexcept;
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void clear( ) noexcept;
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// ---------------------------------------------------------------------
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// Copy constructors
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T_RcPtr( T_Self const& other ) noexcept;
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template< typename Q , T_EnableForChild< Type , Q > = true >
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T_RcPtr( T_RcPtr< Q > const& source ) noexcept;
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template< typename Q , T_EnableForParent< Type , Q > = false >
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explicit T_RcPtr( T_RcPtr< Q > const& source );
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// ---------------------------------------------------------------------
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// Move constructors
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template< typename Q , T_EnableForChild< Type , Q > = true >
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T_RcPtr( T_RcPtr< Q >&& other ) noexcept;
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template< typename Q , T_EnableForParent< Type , Q > = false >
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explicit T_RcPtr( T_RcPtr< Q >&& other );
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};
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} // namespace
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#endif // _H_EBCL_REFCOUNT
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#include <ebcl/inline/RefCount.hh>
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129
include/ebcl/inline/RefCount.hh
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129
include/ebcl/inline/RefCount.hh
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/******************************************************************************/
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/* REFERENCE-COUNTING HELPERS - INLINE CODE ***********************************/
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/******************************************************************************/
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#ifndef _H_EBCL_INLINE_REFCOUNT
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#define _H_EBCL_INLINE_REFCOUNT
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#include <ebcl/RefCount.hh>
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namespace ebcl {
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/*= T_ReferenceCountedClass ==================================================*/
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template< bool B >
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inline T_ReferenceCountedClass< B >::T_ReferenceCountedClass( ) noexcept
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: referenceCounter_{ 0 }
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{ }
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template< bool B >
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inline void T_ReferenceCountedClass< B >::increaseReferences_( ) noexcept
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{
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referenceCounter_ ++;
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}
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template< bool B >
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inline bool T_ReferenceCountedClass< B >::decreaseReferences_( ) noexcept
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{
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return ( -- referenceCounter_ ) == 0;
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}
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/*= T_RcPtr ==================================================================*/
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template< typename T >
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inline T_RcPtr< T >::T_RcPtr( ) noexcept
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: target_{ nullptr }
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{ }
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template< typename T >
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inline T_RcPtr< T >::~T_RcPtr( ) noexcept
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{
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clear( );
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}
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template< typename T >
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inline void T_RcPtr< T >::clear( ) noexcept
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{
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if ( target_ && target_->decreaseReferences_( ) ) {
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delete target_;
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}
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target_ = nullptr;
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}
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/*----------------------------------------------------------------------------*/
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template< typename T >
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inline T_RcPtr< T >::T_RcPtr(
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T_RcPtr< T > const& other ) noexcept
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: target_{ other.target_ }
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{
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if ( target_ ) {
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target_->increaseReferences_( );
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}
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}
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template< typename T >
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template<
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typename Q ,
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T_EnableForChild< T , Q >
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> inline T_RcPtr< T >::T_RcPtr(
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T_RcPtr< Q > const& other ) noexcept
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: target_{ other.target_ }
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{
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if ( target_ ) {
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target_->increaseReferences_( );
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}
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}
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template< typename T >
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template<
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typename Q ,
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T_EnableForParent< T , Q >
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> inline T_RcPtr< T >::T_RcPtr(
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T_RcPtr< Q > const& other )
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: target_{ nullptr }
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{
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Q* const p{ other.target_ };
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if ( p != nullptr ) {
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target_ = dynamic_cast< T* >( p );
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if ( target_ == nullptr ) {
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throw std::bad_cast( );
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}
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target_->increaseReferences_( );
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}
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}
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/*----------------------------------------------------------------------------*/
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template< typename T >
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template<
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typename Q ,
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T_EnableForChild< T , Q >
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> inline T_RcPtr< T >::T_RcPtr(
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T_RcPtr< Q >&& other ) noexcept
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: target_{ nullptr }
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{
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std::swap( target_ , other.target_ );
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}
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template< typename T >
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template<
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typename Q ,
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T_EnableForParent< T , Q >
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> inline T_RcPtr< T >::T_RcPtr(
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T_RcPtr< Q >&& other )
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: target_{ nullptr }
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{
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Q* const p{ other.target_ };
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if ( p != nullptr ) {
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target_ = dynamic_cast< T* >( p );
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if ( target_ == nullptr ) {
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throw std::bad_cast( );
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}
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other.target_ = nullptr;
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}
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}
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} // namespace ebcl
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#endif // _H_EBCL_INLINE_REFCOUNT
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