smart_pointer.h

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#ifndef GEOGRAM_BASIC_SMART_POINTER
#define GEOGRAM_BASIC_SMART_POINTER
 
#include <geogram/basic/common.h>
#include <geogram/basic/assert.h>
#include <geogram/basic/memory.h>
 
namespace GEO {
 
    /************************************************************************/
 
    template <class T>
    class SmartPointer {
    public:
        SmartPointer() :
            pointer_(nullptr) {
        }
 
        SmartPointer(T* ptr) :
            pointer_(ptr) {
            T::ref(pointer_);
        }
 
        SmartPointer(const SmartPointer<T>& rhs) :
            pointer_(rhs) {
            T::ref(pointer_);
        }
 
        ~SmartPointer() {
            T::unref(pointer_);
        }
 
        SmartPointer<T>& operator= (T* ptr) {
            if(ptr != pointer_) {
                T::unref(pointer_);
                pointer_ = ptr;
                T::ref(pointer_);
            }
            return *this;
        }
 
        SmartPointer<T>& operator= (const SmartPointer<T>& rhs) {
            T* rhs_p = rhs.get();
            if(rhs_p != pointer_) {
                T::unref(pointer_);
                pointer_ = rhs_p;
                T::ref(pointer_);
            }
            return *this;
        }
 
        void reset() {
            T::unref(pointer_);
            pointer_ = nullptr;
        }
 
        T* operator-> () const {
            geo_assert(pointer_ != nullptr);
            return pointer_;
        }
 
        T& operator* () const {
            geo_assert(pointer_ != nullptr);
            return *pointer_;
        }
 
        operator T* () const {
            return pointer_;
        }
 
        T* get() const {
            return pointer_;
        }
 
        bool is_null() const {
            return pointer_ == nullptr;
        }
 
    private:
        T* pointer_;
    };
 
    template <class T1, class T2>
    inline bool operator== (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() == rhs.get();
    }
 
    template <class T1, class T2>
    inline bool operator!= (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() != rhs.get();
    }
 
    template <class T1, class T2>
    inline bool operator< (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() < rhs.get();
    }
 
    template <class T1, class T2>
    inline bool operator<= (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() <= rhs.get();
    }
 
    template <class T1, class T2>
    inline bool operator> (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() > rhs.get();
    }
 
    template <class T1, class T2>
    inline bool operator>= (
        const SmartPointer<T1>& lhs, const SmartPointer<T2>& rhs
    ) {
        return lhs.get() >= rhs.get();
    }
}
 
#endif