Detailed Description

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>
class CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >

The CYICowPtr is a smart pointer that performs a shallow-copy when duplicated, and a deep-copy only when a copy is altered.

COW stands for 'Copy-on-write'. Copy-on-write is an optimization strategy that prevents unnecessary allocation and will only perform an allocation on a copy that has been altered, or explicitly requested to be detached.

Constant access to the pointer are deemed to be reading the pointer and will never perform a deep-copy, while non-constant access to the pointer will always assume that the pointer value is going to be changed, and a deep-copy will be performed. Therefore, const-correctness is essential for CYICowPtr to work properly

Here is essentially how to properly use the CYICowPtr:

struct MyClassData
{
     int32_t m_nData1;
     float m_fData2;
}
class MyClass
{
private:
     CYICowPtr<MyClassData> m_pData;
public:
     MyClass() : m_pData(new MyClassData())
     {
     }
     int32_t GetData1() const // constant function, so the data will not be detached
     {
         return m_pData->m_nData1;
     }
     float GetData2() const // constant function, so the data will not be detached
     {
         return m_pData->m_fData2;
     }
     void SetData1(int32_t nData) // non-constant function, so the data will be detached
     {
         m_pData->m_nData1 = nData;
     }
     void SetData2(float fData) // non-constant function, so the data will be detached
     {
         m_pData->m_fData2 = fData;
     }
};
void main()
{
     MyClass m1;
     MyClass m2 = m1; // shallow copy of m_pData is made
     int32_t nData = m1.GetData1();
     float fData = m2.GetData2();
     m2.SetData2(3.0f); //Detach() is called, copy-on-write is performed.  m1 and m2 are now 2 distinct copies
}

Remarks: CYICowPtr is thread-safe

#include <smartptr/YiCowPtr.h>

Public Types
typedef YI_PTR_TYPE *	CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >YI_UNSPECIFIED_BOOL_TYPE

Public Member Functions
	CYICowPtr ()

	CYICowPtr (YI_PTR_TYPE *pData)

	CYICowPtr (const CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > &rOther)

template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >
	CYICowPtr (const CYICowPtr< YI_OTHER_PTR_TYPE, YI_OTHER_DELETE_FUNCTOR > &rOther)

	~CYICowPtr ()

void	Detach ()

void	Reset ()

const YI_PTR_TYPE &	operator* () const

YI_PTR_TYPE &	operator* ()

const YI_PTR_TYPE *	operator-> () const

YI_PTR_TYPE *	operator-> ()

bool	operator! () const

	operator YI_UNSPECIFIED_BOOL_TYPE () const

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > &	operator= (const CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > &rOther)

template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >
CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > &	operator= (const CYICowPtr< YI_OTHER_PTR_TYPE, YI_OTHER_DELETE_FUNCTOR > &rOther)

const YI_PTR_TYPE *	Get () const

bool	IsNull () const

int32_t	GetRefCount () const

void	Swap (CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > &rPtr)

Protected Member Functions
void	Ref ()

void	Deref ()

Protected Attributes
YI_DELETE_FUNCTOR	DeleteFunc

CYIReferenceCounter *	m_pRefCounter

YI_PTR_TYPE *	m_pData

Friends
template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >
class	CYICowPtr

Member Typedef Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

typedef YI_PTR_TYPE* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >YI_UNSPECIFIED_BOOL_TYPE

Constructor & Destructor Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::CYICowPtr ( )

inline

Constructs CYICowPtr and sets its internal object to nullptr

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::CYICowPtr ( YI_PTR_TYPE * pData )

inlineexplicit

Constructs CYICowPtr and sets its internal object to the provided parameter

Parameters

pData the data to track reference count

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::CYICowPtr ( const CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > & rOther )

inline

Copy-constructor that constructs CYICowPtr and sets its internal object from another CYICowPtr of the same type

Parameters

rOther the pointer to track reference count

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::CYICowPtr ( const CYICowPtr< YI_OTHER_PTR_TYPE, YI_OTHER_DELETE_FUNCTOR > & rOther )

inline

Constructs CYICowPtr and sets its internal object from another CYICowPtr of a different type

Warning: Make sure the types are compatible since the implementation is making a C-Style cast

Parameters

rOther the pointer track reference count

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::~CYICowPtr ( )

inline

Destructor will only delete the internal pointer if and only if this instance is the last CYICowPtr to have a reference to our object

Member Function Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

void CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Deref ( )

inlineprotected

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

void CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Detach ( )

inline

This function requests a deep-copy. It will only perform a deep copy if and only if the internal pointer is valid and also if and only if the reference count is greater than one.

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

const YI_PTR_TYPE* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Get ( ) const

inline

Accesses the internal object without taking ownership. Mostly for legacy code compatibility.

Example:

void my_legacy_function(MyData *pPtr)
{
   ...
}
void Func()
{
     CYICowPtr<MyData> pData(new MyData);
     my_legacy_function(pData.Get());
}

Returns: Returns the internal object

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

int32_t CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::GetRefCount ( ) const

inline

Gets the reference count. If the object is nullptr, this function will return 0

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

bool CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::IsNull ( ) const

inline

Syntactic sugar for the operator!()

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData);
     if (pData.IsNull()) // will be false
     {
     }
     ...
     pData.Reset();
     if (pData.IsNull()) // will be true since the internal object is now null.
     {
     }
}

Returns: Returns true if the internal object is null, false otherwise.

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator YI_UNSPECIFIED_BOOL_TYPE ( ) const

inline

This operator tests if the instance is not null, and will work even when compiler does not support the 'bool' keyword Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData);
     if (pData) // will be true
     {
     }
     ...
     pData.Reset();
     if (pData) // will be false since the internal object is now null.
     {
     }
}

Returns: Returns true if the internal object is not null, false otherwise.

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

bool CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator! ( ) const

inline

This operator tests if the instance is null

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData);
     if (!pData) // will be false
     {
     }
     ...
     pData.Reset();
     if (!pData) // will be true since the internal object is now null.
     {
     }
}

Returns: Returns true if the internal object is null, false otherwise.

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

const YI_PTR_TYPE& CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator* ( ) const

inline

Dereferences the internal object. If the internal object is null, the behavior is undefined.

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData());
     (*pData).SetValue(42);
     ...
}

Returns: Returns dereferenced internal object

Remarks: This function does not call Detach()

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

YI_PTR_TYPE& CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator* ( )

inline

Dereferences the internal object. If the internal object is null, the behavior is undefined.

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData());
     (*pData).SetValue(42);
     ...
}

Returns: Returns dereferenced internal object

Remarks: This function calls Detach()

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

const YI_PTR_TYPE* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator-> ( ) const

inline

Directly accesses the internal object's members. If the internal object is null, the behavior is undefined.

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData());
     pData->SetValue(42);
     ...
}

Returns: Returns the internal object

Remarks: This function does not call Detach()

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

YI_PTR_TYPE* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator-> ( )

inline

Directly accesses the internal object's members. If the internal object is null, the behavior is undefined.

Example:

void Func()
{
     CYICowPtr<MyData> pData(new MyData());
     pData->SetValue(42);
     ...
}

Returns: Returns the internal object

Remarks: This function calls Detach()

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYICowPtr<YI_PTR_TYPE, YI_DELETE_FUNCTOR>& CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator= ( const CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > & rOther )

inline

This function resets the internal object to the one provided as a parameter.

If the previous instance was the last reference of its object, the previous object will be promptly deleted.

Parameters

rOther the pointer track reference count

Returns: Returns itself to allow daisy-chaining

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >

CYICowPtr<YI_PTR_TYPE, YI_DELETE_FUNCTOR>& CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::operator= ( const CYICowPtr< YI_OTHER_PTR_TYPE, YI_OTHER_DELETE_FUNCTOR > & rOther )

inline

This function resets the internal object to the one provided as a parameter.

If the previous instance was the last reference of its object, the previous object will be promptly deleted.

Parameters

rOther the pointer track reference count

Returns: Returns itself to allow daisy-chaining

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

void CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Ref ( )

inlineprotected

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

void CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Reset ( )

inline

This function resets the internal object to nullptr.

If the previous instance was the last reference of its object, the previous object will be promptly deleted.

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

void CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::Swap ( CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR > & rPtr )

inline

Swap function that will move the ownership of a object to a different CYICowPtr that could be living in a completely different scope.

Example:

class MyClass
{
private:
     CYICowPtr<MyData> m_pData;
public:
     MyClass() : m_pData(new MyData())
     {
     }
     void Swap(CYICowPtr<MyData> &pData)
     {
         m_pData.Swap(pData);  // instance from the class swapped with instance from this function
     }
};

Parameters

rPtr	the CYIScopedPtr to swap ownership with

Friends And Related Function Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

template<typename YI_OTHER_PTR_TYPE , typename YI_OTHER_DELETE_FUNCTOR >

friend class CYICowPtr

friend

Member Data Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

YI_DELETE_FUNCTOR CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::DeleteFunc

protected

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

YI_PTR_TYPE* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::m_pData

protected

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>

CYIReferenceCounter* CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >::m_pRefCounter

protected

The documentation for this class was generated from the following file:

smartptr/YiCowPtr.h

Detailed Description

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>> class CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

template<typename YI_PTR_TYPE, typename YI_DELETE_FUNCTOR = CYICheckedDeleteFunctor<YI_PTR_TYPE>>
class CYICowPtr< YI_PTR_TYPE, YI_DELETE_FUNCTOR >