source/core/refptr.h

   1 /* $Id$
   2
   3 This file is part of libmspcore
   4 Copyright © 2006-2007 Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7 #ifndef MSP_CORE_REFPTR_H_
   8 #define MSP_CORE_REFPTR_H_
   9
  10 namespace Msp {
  11
  12 template<typename T>
  13 class RefPtr
  14 {
  15 public:
  16         RefPtr(): data(0), count(0) { }
  17         RefPtr(T *d): data(d), count(0) { if(data) count=new unsigned(1); }
  18         RefPtr(const RefPtr &p): data(p.data), count(p.count) { incref(); }
  19         ~RefPtr() { decref(); }
  20
  21         RefPtr &operator=(const RefPtr &p)
  22         {
  23                 decref();
  24                 data=p.data;
  25                 count=p.count;
  26                 incref();
  27                 return *this;
  28         }
  29
  30         T *get() const        { return data; }
  31         T &operator*() const  { return *data; }
  32         T *operator->() const { return data; }
  33         operator bool() const { return data!=0; }
  34
  35         template<typename U>
  36         static RefPtr<T> cast_dynamic(const RefPtr<U> &p)  { return RefPtr<T>(dynamic_cast<T *>(p.get()), p.count); }
  37         template<typename U> friend class RefPtr;
  38 private:
  39         T        *data;
  40         unsigned *count;
  41
  42         RefPtr(T *d, unsigned *c): data(d), count(c) { incref(); }
  43
  44         void  incref()
  45         {
  46                 if(!count) return;
  47                 ++*count;
  48         }
  49
  50         void  decref()
  51         {
  52                 if(!count) return;
  53                 --*count;
  54                 if(!*count)
  55                 {
  56                         delete data;
  57                         delete count;
  58                         data=0;
  59                         count=0;
  60                 }
  61         }
  62 };
  63
  64 } // namespace Msp
  65
  66 #endif