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/*
Copyright (C) 2011 Grame
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Grame Research Laboratory, 9 rue du Garet, 69001 Lyon - France
research@grame.fr
*/
#ifndef __smartpointer__
#define __smartpointer__
#include "exception.hh"
/*!
\brief the base class for smart pointers implementation
Any object that want to support smart pointers should
inherit from the smartable class which provides reference counting
and automatic delete when the reference count drops to zero.
*/
class smartable {
private:
unsigned refCount;
public:
//! gives the reference count of the object
unsigned refs() const { return refCount; }
//! addReference increments the ref count and checks for refCount overflow
void addReference()
{
refCount++;
faustassert(refCount != 0);
}
//! removeReference delete the object when refCount is zero
void removeReference()
{
if (--refCount == 0) {
delete this;
}
}
protected:
smartable() : refCount(0) {}
smartable(const smartable&) : refCount(0) {}
//! destructor checks for non-zero refCount
virtual ~smartable()
{
// printf(" ~smartable() \n");
// faustassert(refCount == 0);
}
smartable& operator=(const smartable&) { return *this; }
};
/*!
\brief the smart pointer implementation
A smart pointer is in charge of maintaining the objects reference count
by the way of pointers operators overloading. It supports class
inheritance and conversion whenever possible.
\n Instances of the SMARTP class are supposed to use \e smartable types (or at least
objects that implements the \e addReference and \e removeReference
methods in a consistent way).
*/
template <class T>
class SMARTP {
private:
//! the actual pointer to the class
T* fSmartPtr;
public:
//! an empty constructor - points to null
SMARTP() : fSmartPtr(0) {}
//! build a smart pointer from a class pointer
SMARTP(T* rawptr) : fSmartPtr(rawptr)
{
if (fSmartPtr) {
fSmartPtr->addReference();
}
}
//! build a smart pointer from an convertible class reference
template <class T2>
SMARTP(const SMARTP<T2>& ptr) : fSmartPtr((T*)ptr)
{
if (fSmartPtr) {
fSmartPtr->addReference();
}
}
//! build a smart pointer from another smart pointer reference
SMARTP(const SMARTP& ptr) : fSmartPtr((T*)ptr)
{
if (fSmartPtr) {
fSmartPtr->addReference();
}
}
//! the smart pointer destructor: simply removes one reference count
~SMARTP()
{
if (fSmartPtr) {
fSmartPtr->removeReference();
}
}
//! cast operator to retrieve the actual class pointer
operator T*() const { return fSmartPtr; }
//! '*' operator to access the actual class pointer
T& operator*() const
{
// checks for null dereference
faustassert(fSmartPtr != 0);
return *fSmartPtr;
}
//! operator -> overloading to access the actual class pointer
T* operator->() const
{
// checks for null dereference
faustassert(fSmartPtr != 0);
return fSmartPtr;
}
//! operator = that moves the actual class pointer
template <class T2>
SMARTP& operator=(T2 p1_)
{
*this = (T*)p1_;
return *this;
}
//! operator = that moves the actual class pointer
SMARTP& operator=(T* p_)
{
// check first that pointers differ
if (fSmartPtr != p_) {
// increments the ref count of the new pointer if not null
if (p_ != 0) {
p_->addReference();
}
// decrements the ref count of the old pointer if not null
if (fSmartPtr != 0) {
fSmartPtr->removeReference();
}
// and finally stores the new actual pointer
fSmartPtr = p_;
}
return *this;
}
//! operator < to support SMARTP map with Visual C++
bool operator<(const SMARTP<T>& p_) const { return fSmartPtr < ((T*)p_); }
//! operator = to support inherited class reference
SMARTP& operator=(const SMARTP<T>& p_) { return operator=((T*)p_); }
//! dynamic cast support
template <class T2>
SMARTP& cast(T2* p_)
{
return operator=(dynamic_cast<T*>(p_));
}
//! dynamic cast support
template <class T2>
SMARTP& cast(const SMARTP<T2>& p_)
{
return operator=(dynamic_cast<T*>(p_));
}
};
#endif
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