#include #include #include inline constexpr bool TEST{ true }; template < typename T > class Deleter { public: constexpr Deleter() noexcept = default; inline void operator () ( T* ptr ) const { if constexpr ( TEST ) { std::cout << "Deleter< T > called.\n"; } ::delete( ptr ); } }; template < typename T > class Deleter< T[] > { public: constexpr Deleter() noexcept = default; inline void operator () ( T* ptr ) const { if constexpr ( TEST ) { std::cout << "Deleter< T[] > called.\n"; } ::delete [] ( ptr ); } }; class NullPointerException : public std::runtime_error { public: NullPointerException() noexcept : std::runtime_error{ "Error: SmartPointer is empty." } {} }; template < typename T, typename D = Deleter< T > > class SmartPointer { private: using element_type = T; using deleter_type = D; using pointer = T*; pointer ptr; deleter_type deleter; void testForNullptr() const; public: explicit SmartPointer( pointer = nullptr ) noexcept; SmartPointer( pointer, const D& ) noexcept; SmartPointer( pointer, D&& ) noexcept; SmartPointer( SmartPointer&& ) noexcept; SmartPointer( const SmartPointer& ) = delete; ~SmartPointer(); SmartPointer& operator = ( SmartPointer&& ) noexcept; SmartPointer& operator = ( const SmartPointer& ) = delete; element_type& operator * () const; pointer operator -> () const; explicit operator bool () const noexcept; pointer get_pointer() const noexcept; deleter_type& get_deleter() noexcept; const deleter_type& get_deleter() const noexcept; pointer release_pointer() noexcept; void reset( pointer = pointer() ) noexcept; void swap( SmartPointer& ) noexcept; }; template < typename T, typename D > void SmartPointer< T, D >::testForNullptr() const { if ( this->ptr == nullptr ) { throw NullPointerException(); } } template < typename T, typename D > SmartPointer< T, D >::SmartPointer( pointer ptr ) noexcept : ptr{ ptr }, deleter{ Deleter< T >() } {} template < typename T, typename D > SmartPointer< T, D >::SmartPointer( pointer ptr, const D& deleter ) noexcept : ptr{ ptr }, deleter{ deleter } {} template < typename T, typename D > SmartPointer< T, D >::SmartPointer( pointer ptr, D&& deleter ) noexcept : ptr{ ptr }, deleter{ std::move( deleter ) } {} template < typename T, typename D > SmartPointer< T, D >::SmartPointer( SmartPointer< T, D >&& smartPtr ) noexcept : ptr{ std::move( smartPtr.ptr ) }, deleter{ std::move( smartPtr.deleter ) } { smartPtr.ptr = nullptr; } template < typename T, typename D > SmartPointer< T, D >::~SmartPointer() { if ( this->ptr != nullptr ) { this->deleter( this->ptr ); } if constexpr ( TEST ) { std::cout << "SmartPointer< T > deleted.\n"; } } template < typename T, typename D > SmartPointer< T, D >& SmartPointer< T, D >::operator = ( SmartPointer< T, D >&& smartPtr ) noexcept { this->ptr = std::move( smartPtr.ptr ); this->deleter = std::move( smartPtr.deleter ); smartPtr.ptr = nullptr; return *this; } template < typename T, typename D > T& SmartPointer< T, D >::operator * () const { this->testForNullptr(); return *( this->ptr ); } template < typename T, typename D > T* SmartPointer< T, D >::operator -> () const { this->testForNullptr(); return this->ptr; } template < typename T, typename D > SmartPointer< T, D >::operator bool () const noexcept { return ( this->ptr != nullptr ); } template < typename T, typename D > T* SmartPointer< T, D >::get_pointer() const noexcept { return this->ptr; } template < typename T, typename D > D& SmartPointer< T, D >::get_deleter() noexcept { return this->deleter; } template < typename T, typename D > const D& SmartPointer< T, D >::get_deleter() const noexcept { return this->deleter; } template < typename T, typename D > T* SmartPointer< T, D >::release_pointer() noexcept { T* tempPtr { this->ptr }; this->ptr = nullptr; return tempPtr; } template < typename T, typename D > void SmartPointer< T, D >::reset( T* ptr ) noexcept { if ( this->ptr != nullptr ) { this->deleter( this->ptr ); } this->ptr = ptr; } template < typename T, typename D > void SmartPointer< T, D >::swap( SmartPointer& smartPtr ) noexcept { std::swap( this->ptr, smartPtr.ptr ); std::swap( this->deleter, smartPtr.deleter ); } template < typename T, typename D > class SmartPointer< T[], D > { private: using element_type = T; using deleter_type = D; using pointer = T*; pointer ptr; deleter_type deleter; void testForNullptr() const; public: explicit SmartPointer( pointer = nullptr ) noexcept; SmartPointer( pointer, const D& ) noexcept; SmartPointer( pointer, D&& ) noexcept; SmartPointer( SmartPointer&& ) noexcept; SmartPointer( const SmartPointer& ) = delete; ~SmartPointer(); SmartPointer& operator = ( SmartPointer&& ) noexcept; SmartPointer& operator = ( const SmartPointer& ) = delete; element_type& operator [] ( const std::size_t ) const; explicit operator bool () const noexcept; pointer get_pointer() const noexcept; deleter_type& get_deleter() noexcept; const deleter_type& get_deleter() const noexcept; pointer release_pointer() noexcept; void reset( pointer = pointer() ) noexcept; void swap( SmartPointer& ) noexcept; }; template < typename T, typename D > void SmartPointer< T[], D >::testForNullptr() const { if ( this->ptr == nullptr ) { throw NullPointerException(); } } template < typename T, typename D > SmartPointer< T[], D >::SmartPointer( pointer ptr ) noexcept : ptr{ ptr }, deleter{ Deleter< T[] >() } {} template < typename T, typename D > SmartPointer< T[], D >::SmartPointer( pointer ptr, const D& deleter ) noexcept : ptr{ ptr }, deleter{ deleter } {} template < typename T, typename D > SmartPointer< T[], D >::SmartPointer( pointer ptr, D&& deleter ) noexcept : ptr{ ptr }, deleter{ std::move( deleter ) } {} template < typename T, typename D > SmartPointer< T[], D >::SmartPointer( SmartPointer< T[], D >&& smartPtr ) noexcept : ptr{ std::move( smartPtr.ptr ) }, deleter{ std::move( smartPtr.deleter ) } { smartPtr.ptr = nullptr; } template < typename T, typename D > SmartPointer< T[], D >::~SmartPointer() { if ( this->ptr != nullptr ) { this->deleter( this->ptr ); } if constexpr ( TEST ) { std::cout << "SmartPointer< T[] > deleted.\n"; } } template < typename T, typename D > SmartPointer< T[], D >& SmartPointer< T[], D >::operator = ( SmartPointer< T[], D >&& smartPtr ) noexcept { this->ptr = std::move( smartPtr.ptr ); this->deleter = std::move( smartPtr.deleter ); smartPtr.ptr = nullptr; return *this; } template < typename T, typename D > T& SmartPointer< T[], D >::operator [] ( const std::size_t index ) const { this->testForNullptr(); return *( this->ptr + index ); } template < typename T, typename D > SmartPointer< T[], D >::operator bool () const noexcept { return ( this->ptr != nullptr ); } template < typename T, typename D > T* SmartPointer< T[], D >::get_pointer() const noexcept { return this->ptr; } template < typename T, typename D > D& SmartPointer< T[], D >::get_deleter() noexcept { return this->deleter; } template < typename T, typename D > const D& SmartPointer< T[], D >::get_deleter() const noexcept { return this->deleter; } template < typename T, typename D > T* SmartPointer< T[], D >::release_pointer() noexcept { T* tempPtr { this->ptr }; this->ptr = nullptr; return tempPtr; } template < typename T, typename D > void SmartPointer< T[], D >::reset( T* ptr ) noexcept { if ( this->ptr != nullptr ) { this->deleter( this->ptr ); } this->ptr = ptr; } template < typename T, typename D > void SmartPointer< T[], D >::swap( SmartPointer< T[], D>& smartPtr ) noexcept { std::swap( this->ptr, smartPtr.ptr ); std::swap( this->deleter, smartPtr.deleter ); } template < typename T1, typename D1, typename T2, typename D2> bool operator == ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() == rhs.get_pointer() ); } template < typename T, typename D > bool operator == ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() == rhs ); } template < typename T, typename D > bool operator == ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs == rhs.get_pointer() ); } template < typename T1, typename D1, typename T2, typename D2 > bool operator != ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() != rhs.get_pointer() ); } template < typename T, typename D > bool operator != ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() != rhs ); } template < typename T, typename D > bool operator != ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs != rhs.get_pointer() ); } template < typename T1, typename D1, typename T2, typename D2 > bool operator < ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() < rhs.get_pointer() ); } template < typename T, typename D > bool operator < ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() < rhs ); } template < typename T, typename D > bool operator < ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs < rhs.get_pointer() ); } template < typename T1, typename D1, typename T2, typename D2 > bool operator <= ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() <= rhs.get_pointer() ); } template < typename T, typename D > bool operator <= ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() <= rhs ); } template < typename T, typename D > bool operator <= ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs <= rhs.get_pointer() ); } template < typename T1, typename D1, typename T2, typename D2 > bool operator > ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() > rhs.get_pointer() ); } template < typename T, typename D > bool operator > ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() > rhs ); } template < typename T, typename D > bool operator > ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs > rhs.get_pointer() ); } template < typename T1, typename D1, typename T2, typename D2 > bool operator >= ( const SmartPointer< T1, D1 >& lhs, const SmartPointer< T2, D2 >& rhs ) { return ( lhs.get_pointer() >= rhs.get_pointer() ); } template < typename T, typename D > bool operator >= ( const SmartPointer< T, D >& lhs, const std::nullptr_t rhs ) { return ( lhs.get_pointer() >= rhs ); } template < typename T, typename D > bool operator >= ( const std::nullptr_t lhs, const SmartPointer< T, D >& rhs ) { return ( lhs >= rhs.get_pointer() ); } int main( int argc, char** argv ) { std::cout << std::boolalpha; std::cout << "~~~Start of main scope~~~\n\n"; SmartPointer< int > myPtr{ new int }; std::cout << "SmartPointer< int > initialized!\n"; *myPtr = 10; std::cout << "Value of myPtr = " << *myPtr << "\n"; std::cout << "\n~~~Start of local scope~~~\n\n"; { SmartPointer< int[] > localPtr{ new int[ 5 ] }; std::cout << "Local SmartPointer< int[] > initalized!\n"; std::cout << "Filling array with values...\n"; for ( std::size_t i{ 0 }; i < 5; ++i ) { localPtr[ i ] = ( i + 1 ) * 2; } std::cout << "Values of localPtr = "; for ( std::size_t i{ 0 }; i < 5; ++i ) { std::cout << localPtr[ i ] << " "; } std::cout << "\n\nmyPtr == localPtr?\n=> " << ( myPtr == localPtr ) << "\n\n"; } std::cout << "\n~~~End of local scope~~~\n\n"; std::cout << "Resetting myPtr...\n"; myPtr.reset(); std::cout << "\nmyPtr == nullptr?\n=> " << ( myPtr == nullptr ) << "\n"; std::cout << "\n~~~End of main scope~~~\n\n"; return EXIT_SUCCESS; }

Attempt on smart pointers