0.6.0-1 release

[manu/suphp.git] / src / SmartPtr.hpp

diff --git a/src/SmartPtr.hpp b/src/SmartPtr.hpp
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+/*
+    suPHP - (c)2002-2005 Sebastian Marsching <sebastian@marsching.com>
+
+    This file is part of suPHP.
+
+    suPHP is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    suPHP 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with suPHP; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#ifndef SUPHP_SMARTPTR_H
+
+namespace suPHP {
+    class Environment;
+};
+
+#define SUPHP_SMARTPTR_H
+
+#include <map>
+#include <cstdlib>
+#include "PointerException.hpp"
+
+namespace suPHP {
+    /**
+     * Class template encapsulating pointers.
+     */
+    template<class T>
+    class SmartPtr {
+    private:
+       static std::map<T*, int> counter;
+       T* ptr;
+       
+       void increment(T* key_ptr);
+       void decrement(T* key_ptr);
+       
+    public:
+       /**
+        * Constructor using NULL pointer
+        */
+       SmartPtr();
+       
+       /**
+        * Constructor taking T* as argument
+        */
+       SmartPtr(T* obj_ptr);
+
+       /**
+        * Copy constructor
+        */
+       SmartPtr(const SmartPtr<T>& ref);
+       
+       /**
+        * Destructor
+        */
+       ~SmartPtr();
+       
+       /**
+        * Copy operator
+        */
+       const SmartPtr& operator=(const SmartPtr<T>& ref);
+
+       /**
+        * Dereference operator.
+        * Returns reference to object hold by smart pointer
+        */
+       T& operator*() const throw(PointerException);
+       
+       /**
+        * Member access operator
+        */
+       T* operator->() const throw(PointerException);
+       
+       /**
+        * Returns underlying pointer
+        */
+       T* get() const;
+       
+       /**
+        * Returns underlying pointer and releases it
+        * from management by the SmartPtr.
+        * Throws an exception if underlying pointer is
+        * hold by more than one SmartPtr.
+        */
+       T* release() throw (PointerException);
+       
+       /**
+        * Resets SmartPtr to point to another object
+        */
+       void reset(T* obj_ptr);
+       
+       /**
+        * Compares to pointers.
+        * Returns true, if both point to the same object,
+        * false otherwise
+        */
+       bool operator==(const SmartPtr<T>& ref);
+       
+    };
+
+    template<class T>
+    std::map<T*, int> suPHP::SmartPtr<T>::counter;
+    
+    template<class T>
+    suPHP::SmartPtr<T>::SmartPtr() {
+       this->ptr = NULL;
+    }
+    
+    template<class T>
+    suPHP::SmartPtr<T>::SmartPtr(T* obj_ptr) {
+       this->ptr = obj_ptr;
+       this->increment(obj_ptr);
+    }
+    
+    template<class T>
+    suPHP::SmartPtr<T>::SmartPtr(const SmartPtr<T>& ref) {
+       this->ptr = ref.ptr;
+       if (ref.ptr != NULL)
+           this->increment(ref.ptr);
+    }
+    
+    template<class T>
+    suPHP::SmartPtr<T>::~SmartPtr() {
+       if (this->ptr != NULL)
+           this->decrement(this->ptr);
+    }
+    
+    template<class T>
+    const SmartPtr<T>& suPHP::SmartPtr<T>::operator=(
+       const SmartPtr<T>& ref) {
+       this.reset(ref.ptr);
+       return *this;
+    }
+    
+    template<class T>
+    T& suPHP::SmartPtr<T>::operator*() const throw (PointerException) {
+       if (this->ptr == NULL)
+           throw PointerException("Cannot dereference NULL pointer", 
+                                  __FILE__, __LINE__);
+       return *(this->ptr);
+    }
+    
+    template<class T>
+    T* suPHP::SmartPtr<T>::operator->() const throw (PointerException) {
+       if (this->ptr == NULL)
+           throw PointerException("Cannot access member of NULL pointer", 
+                                  __FILE__, __LINE__);
+       return this->ptr;
+    }
+    
+    template<class T>
+    T* suPHP::SmartPtr<T>::get() const {
+       return this->ptr;
+    }
+    
+    template<class T>
+    T* suPHP::SmartPtr<T>::release() throw (PointerException) {
+       T* obj_ptr = this->ptr;
+       if (obj_ptr == NULL)
+           return NULL;
+
+       int& c = SmartPtr<T>::counter.find(obj_ptr)->second;
+       
+       if (c > 1) {
+           throw PointerException(
+               "Cannot release object hold by more than one SmartPointer.", 
+               __FILE__, __LINE__);
+       } else {
+           SmartPtr<T>::counter.erase(obj_ptr);
+       }
+       this->ptr = NULL;
+       return obj_ptr;
+    }
+    
+    template<class T>
+    void suPHP::SmartPtr<T>::reset(T* obj_ptr) {
+       if (obj_ptr != this->ptr) {
+           this->decrement(this->ptr);
+           this->ptr = obj_ptr;
+           this->increment(obj_ptr);
+       }
+    }
+    
+    template<class T>
+    void suPHP::SmartPtr<T>::increment(T* key_ptr) {
+       if (key_ptr == NULL)
+           return;
+
+       if (SmartPtr<T>::counter.find(key_ptr) 
+           != SmartPtr<T>::counter.end()) {
+           (SmartPtr<T>::counter.find(key_ptr)->second)++;
+       } else {
+           std::pair<T*, int> p;
+           p.first = key_ptr;
+           p.second = 1;
+           SmartPtr<T>::counter.insert(p);
+       }
+    }
+
+    template<class T>
+    void suPHP::SmartPtr<T>::decrement(T* key_ptr) {
+       if (key_ptr == NULL)
+           return;
+
+       int& c = SmartPtr<T>::counter.find(key_ptr)->second;
+       c--;
+       if (c < 1) {
+           delete key_ptr;
+           SmartPtr<T>::counter.erase(key_ptr);
+       }
+    }
+    
+    template<class T>
+    bool suPHP::SmartPtr<T>::operator==(const SmartPtr<T>& ref) {
+       if (this->get() == ref.get())
+           return true;
+       else
+           return false;
+    }
+
+};
+
+#endif // SUPHP_SMARTPTR_H