#pragma once
#include <memory>
#include "Test.hpp"
namespace smart_pointer {
// `exception` class definition
class exception : std::exception {
using base_class = std::exception;
using base_class::base_class;
};
template<
typename T,
typename Allocator
>
class SmartPointer {
ENABLE_CLASS_TESTS;
public:
using value_type = T;
explicit SmartPointer(value_type* p = nullptr) {
if (p == nullptr)
core = nullptr;
else {
core = new Core(p);
}
}
SmartPointer(const SmartPointer& other) : core(other.core) {
if (other.core != nullptr) core->count++;
}
SmartPointer(SmartPointer&& other) : core(other.core) {
other = nullptr;
}
SmartPointer& operator=(const SmartPointer& other) {
if (&other == this)
return *this;
if (core != nullptr) {
core->count -= 1;
if (core->count == 0) {
delete core;
}
}
core = other.core;
if (other.core != nullptr) {
core->count++;
}
return *this;
}
SmartPointer& operator=(SmartPointer&& other) {
if (&other == this)
return *this;
if (core != nullptr) {
core->count -= 1;
if (core->count == 0) {
delete core;
}
}
core = other.core;
other.core = nullptr;
return *this;
}
SmartPointer& operator=(value_type* p) {
if (core != nullptr) {
core->count -= 1;
if (core->count == 0) {
delete core;
}
}
if (p != nullptr)
core = new Core(p);
else {
core = nullptr;
}
return *this;
}
~SmartPointer() {
}
value_type& operator*() {
if (core != nullptr)
return *(core->p);
throw smart_pointer::exception();
}
const value_type& operator*() const {
if (core != nullptr)
return *(core->p);
throw smart_pointer::exception();
}
value_type* operator->() const {
if (core != nullptr)
return core->p;
return nullptr;
}
value_type* get() const {
if (core != nullptr)
return core->p;
return nullptr;
}
operator bool() const {
return core != nullptr;
}
template<typename U, typename AnotherAllocator>
bool operator==(const SmartPointer<U,
AnotherAllocator>& other) const {
return ((void*)this->get() == (void*)other.get() ||
(!this && !other));
}
template<typename U, typename AnotherAllocator>
bool operator!=(const SmartPointer<U,
AnotherAllocator>& other) const {
return !((void*)this->get() == (void*)other.get() ||
(!this && !other));
}
std::size_t count_owners() const {
if (core == nullptr) return 0;
else return core->count;
};
private:
class Core {
public:
value_type* p;
std::size_t count;
Core(value_type* ptr) : p(ptr), count(1) {}
~Core() {
Allocator a;
a.deallocate(p, sizeof(value_type));
p = nullptr;
}
value_type get() {
return *p;
}
};
Core* core;
};
}