nevrax.org : docs

00001 
+00007 /* Copyright, 2000 Nevrax Ltd.
+00008  *
+00009  * This file is part of NEVRAX NEL.
+00010  * NEVRAX NEL is free software; you can redistribute it and/or modify
+00011  * it under the terms of the GNU General Public License as published by
+00012  * the Free Software Foundation; either version 2, or (at your option)
+00013  * any later version.
+00014 
+00015  * NEVRAX NEL is distributed in the hope that it will be useful, but
+00016  * WITHOUT ANY WARRANTY; without even the implied warranty of
+00017  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+00018  * General Public License for more details.
+00019 
+00020  * You should have received a copy of the GNU General Public License
+00021  * along with NEVRAX NEL; see the file COPYING. If not, write to the
+00022  * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+00023  * MA 02111-1307, USA.
+00024  */
+00025 
+00026 #ifndef NL_SMART_PTR_H
+00027 #define NL_SMART_PTR_H
+00028 
+00029 
+00030 #include "nel/misc/types_nl.h"
+00031 
+00032 #include <stdio.h>
+00033 
+00034 
+00035 namespace NLMISC
+00036 {
+00037 
+00038 
+00039 // ***************************************************************************
+00047 class CRefCount 
+00048 {
+00049 public:
+00050         // The instance handle.
+00051         // Can't put those to private since must be used by CRefPtr (and friend doesn't work with template).
+00052         struct  CPtrInfo
+00053         {
+00054                 void    *Ptr;                   // to know if the instance is valid.
+00055                 sint    RefCount;               // RefCount of ptrinfo (!= instance)
+00056                 // For fu... dll problems, must use a flag to mark NullPtrInfo.
+00057                 bool    IsNullPtrInfo;
+00058 
+00059                 CPtrInfo(void *p) {Ptr=p; RefCount=0; IsNullPtrInfo=false;}
+00060                 // Just for internal use, to mark our Null pointer.
+00061                 CPtrInfo(char ) {Ptr=NULL; RefCount=0x7FFFFFFF; IsNullPtrInfo=true;}
+00062         };
+00063 
+00064         // OWN null for ref ptr. (Optimisations!!!)
+00065         static  CPtrInfo        NullPtrInfo;
+00066         friend struct           CPtrInfo;
+00067                 
+00068 public:
+00069         // Can't put this to private since must be used by CSmartPtr (and friend doesn't work with template).
+00070         // Provide incref()/decref() function doen't work since decref() can't do a delete this on a non virtual dtor.
+00071         // So Ptr gestion can only be used via CSmartPtr.
+00072     mutable     sint            crefs;  // The ref counter for SmartPtr use.
+00073         mutable CPtrInfo        *pinfo; // The ref ptr for RefPtr use.
+00074         
+00076         ~CRefCount();
+00078     CRefCount() { crefs = 0; pinfo=&NullPtrInfo; }
+00080         CRefCount &operator=(const CRefCount &) {return *this;}
+00082         CRefCount(const CRefCount &) {crefs = 0; pinfo=&NullPtrInfo;}
+00083 };
+00084 
+00085 
+00086 
+00087 // ***************************************************************************
+00088 // For debug only.
+00089 #define SMART_TRACE(_s) ((void)0)
+00090 #define REF_TRACE(_s)   ((void)0)
+00091 //#define       SMART_TRACE(_s) printf("%s: %d \n", _s, Ptr?Ptr->crefs:0)
+00092 //#define       REF_TRACE(_s)   printf("%s: %d \n", _s, pinfo!=&CRefCount::NullPtrInfo?pinfo->RefCount:0)
+00093 
+00094 
+00177 template <class T>
+00178 class CSmartPtr 
+00179 {
+00180     T* Ptr;
+00181 public:
+00182 
+00184     CSmartPtr() { Ptr=NULL; SMART_TRACE("ctor()"); }
+00186     CSmartPtr(T* p) { Ptr=p; if(Ptr) Ptr->crefs++; SMART_TRACE("ctor(T*)"); }
+00188     CSmartPtr(const CSmartPtr &copy) { Ptr=copy.Ptr; if(Ptr) Ptr->crefs++; SMART_TRACE("ctor(Copy)"); }
+00190     ~CSmartPtr();
+00191 
+00192 
+00194     operator T*(void) const { SMART_TRACE("castT*()"); return Ptr; }
+00196     T& operator*(void) const { SMART_TRACE("ope*()"); return *Ptr; }
+00198     T* operator->(void) const { SMART_TRACE("ope->()"); return Ptr; }
+00199 
+00201     CSmartPtr& operator=(T* p);
+00203     CSmartPtr& operator=(const CSmartPtr &p);
+00205     bool operator<(const CSmartPtr &p) const;
+00206 
+00207         sint getNbRef() { if(Ptr) return Ptr->crefs; else return 0; }
+00208         // No need to do any operator==. Leave the work to cast  operator T*(void).
+00209 };
+00210 
+00211 
+00212 
+00213 // ***************************************************************************
+00243 template <class T> 
+00244 class CRefPtr
+00245 {
+00246 private:
+00247         CRefCount::CPtrInfo             *pinfo;         // A ptr to the handle of the object.
+00248     mutable T                           *Ptr;           // A cache for pinfo->Ptr. UseFull to speed up  ope->()  and  ope*()
+00249 
+00250         void    unRef()  const;                         // Just release the handle pinfo, but do not update pinfo/Ptr, if deleted.
+00251 
+00252 public:
+00253 
+00255     CRefPtr();
+00257     CRefPtr(T *v);
+00259     CRefPtr(const CRefPtr &copy);
+00261     ~CRefPtr(void);
+00262 
+00263 
+00265         operator T*()   const;
+00267     T& operator*(void)  const;
+00269     T* operator->(void) const;
+00270 
+00271 
+00273         CRefPtr& operator=(T *v);
+00275     CRefPtr& operator=(const CRefPtr &copy);
+00276 
+00277 
+00285         void    kill();
+00286 
+00287 
+00288         // No need to do any operator==. Leave the work to cast  operator T*(void).
+00289 };
+00290 
+00291 
+00292 
+00293 }
+00294 
+00295 
+00296 // ***************************************************************************
+00297 // ***************************************************************************
+00298 // Implementation.
+00299 // ***************************************************************************
+00300 // ***************************************************************************
+00301 
+00302 
+00303 #include "smart_ptr_inline.h"
+00304 #undef  SMART_TRACE
+00305 #undef  REF_TRACE
+00306 
+00307 
+00308 
+00309 #endif // NL_SMART_PTR_H
+00310 
+00311 /* End of smart_ptr.h */
+