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/*!
* @file pointer.h
* @brief Contains a pointer class which has a counter-mechanism to prevent
* memory leak.
*
* @author cathook
*/
#ifndef __MEOWPP_UTILITY_POINTER_H__
#define __MEOWPP_UTILITY_POINTER_H__
#include <cstddef>
#include <cstdlib>
#include "object.h"
namespace meow {
/*!
* @brief Types of pointer.
*/
enum PointerType {
SINGLE = 0,
ARRAY = 1
};
/*!
* @brief A pointer points to the template `Type`.
*/
template<typename Type>
class Pointer : public Object {
private:
struct RealPointer {
Type* address;
//! The type of the address.
PointerType type;
//! Whether the address should be deleted when no one points to it.
bool auto_delete;
//! Stores number of pointers point to it.
int counter;
RealPointer(Type* arg_address,
PointerType arg_type,
bool arg_auto_delete,
int arg_counter) :
address(arg_address),
type(arg_type),
auto_delete(arg_auto_delete),
counter(arg_counter) {}
~RealPointer() {
if (auto_delete) {
switch (type) {
case SINGLE:
delete address;
break;
case ARRAY:
delete [] address;
break;
}
}
}
};
RealPointer* ptr_;
void Attach(RealPointer* arg_ptr2) {
ptr_ = arg_ptr2;
ptr_->counter += 1;
}
void Detach() {
ptr_->counter -= 1;
if (ptr_->counter == 0) {
delete ptr_;
}
}
public:
/*!
* @brief Default constructor, let the pointer points to NULL.
*/
Pointer() : Pointer(NULL, SINGLE, false) {}
/*!
* @brief Copy constructor.
*/
Pointer(Pointer const& arg_ptr) {
Attach(arg_ptr.ptr_);
}
/*!
* @brief Constructor with gived address to point.
*
* If `arg_auto_delete` is `true`, it will automatically delete it when
* there are no instance of Pointer\<Type\> points to that `address`
*
* @param [in] arg_address Points to the address.
* @param [in] arg_type
* @param [in] arg_auto_delete
*/
Pointer(Type* arg_address, PointerType arg_type, bool arg_auto_delete) :
ptr_(new RealPointer(arg_address, arg_type, arg_auto_delete, 1)) {}
/*!
* @brief Destructor.
*/
~Pointer() { Detach(); }
/*!
* @brief Gets whether it will delete the address automatically or not.
*/
bool auto_delete() const {
return ptr_->auto_delete;
}
/*!
* @brief Gets the address it points to.
*/
Type* address() const {
return ptr_->address;
}
/*!
* @brief Same as `address()`
*/
operator Type*() const {
return address();
}
/*!
* @brief Gets the pointer points to the body.
*/
Type* operator->() const {
return address();
}
/*!
* @brief Points to another instance of Pointer.
*/
Pointer& operator=(Pointer const& b) {
Detach();
Attach(b.ptr_);
return *this;
}
Object* Copy() const {
return new Pointer(*this);
}
Object* CopyFrom(Object const* another_pointer) {
(*this) = *dynamic_cast<Pointer const*>(another_pointer);
return this;
}
bool Equals(Object const* another_pointer) {
return (ptr_->address ==
dynamic_cast<Pointer const*>(another_pointer)->ptr_->address);
}
#ifdef MEOWPP_UTILITY_POINTER_TESTING
friend class PointerTest;
#endif // MEOWPP_UTILLITY_POINTER_TESTING
};
} // meow
#endif // __MEOWPP_UTILITY_POINTER_H__
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