include/wx/ptr_scpd.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/ptr_scpd.h
   3 // Purpose:     scoped smart pointer class
   4 // Author:      Jesse Lovelace <jllovela@eos.ncsu.edu>
   5 // Modified by:
   6 // Created:     06/01/02
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Jesse Lovelace and original Boost authors (see below)
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 //  This class closely follows the implementation of the boost
  13 //  library scoped_ptr and is an adaption for c++ macro's in
  14 //  the wxWidgets project. The original authors of the boost
  15 //  scoped_ptr are given below with their respective copyrights.
  16
  17 //  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
  18 //  Copyright (c) 2001, 2002 Peter Dimov
  19 //
  20 //  Permission to copy, use, modify, sell and distribute this software
  21 //  is granted provided this copyright notice appears in all copies.
  22 //  This software is provided "as is" without express or implied
  23 //  warranty, and with no claim as to its suitability for any purpose.
  24 //
  25 //  See http://www.boost.org/libs/smart_ptr/scoped_ptr.htm for documentation.
  26 //
  27
  28 #ifndef __WX_SCOPED_POINTER__
  29 #define __WX_SCOPED_POINTER__
  30
  31 #include "wx/defs.h"
  32
  33 /*
  34    checked deleters are used to make sure that the type being deleted is really
  35    a complete type.: otherwise sizeof() would result in a compile-time error
  36
  37    do { ... } while ( 0 ) construct is used to have an anonymous scope
  38    (otherwise we could have name clashes between different "complete"s) but
  39    still force a semicolon after the macro
  40 */
  41
  42 #define wxCHECKED_DELETE(ptr)                                                 \
  43     do                                                                        \
  44     {                                                                         \
  45         typedef char complete[sizeof(*ptr)];                                  \
  46         delete ptr;                                                           \
  47     } while ( 0 )
  48
  49 #define wxCHECKED_DELETE_ARRAY(ptr)                                           \
  50     do                                                                        \
  51     {                                                                         \
  52         typedef char complete[sizeof(*ptr)];                                  \
  53         delete [] ptr;                                                        \
  54     } while ( 0 )
  55
  56 /* These scoped pointers are *not* assignable and cannot be used
  57    within a container.  Look for wxDECLARE_SHARED_PTR for this
  58    functionality.
  59
  60    In addition, the type being used *must* be complete at the time
  61    that wxDEFINE_SCOPED_* is called or a compiler error will result.
  62    This is because the class checks for the completeness of the type
  63    being used.
  64 */
  65
  66
  67 #define wxDECLARE_SCOPED_PTR(T, name) \
  68 class name                          \
  69 {                                   \
  70 private:                            \
  71     T * m_ptr;                      \
  72                                     \
  73     name(name const &);             \
  74     name & operator=(name const &); \
  75                                     \
  76 public:                             \
  77     wxEXPLICIT name(T * ptr = NULL) \
  78     : m_ptr(ptr) { }                \
  79                                     \
  80     ~name();                        \
  81                                     \
  82     void reset(T * ptr = NULL)      \
  83     {                               \
  84         if (m_ptr != ptr)           \
  85         {                           \
  86             delete m_ptr;           \
  87             m_ptr = ptr;            \
  88         }                           \
  89     }                               \
  90                                     \
  91     T *release()                    \
  92     {                               \
  93         T *ptr = m_ptr;             \
  94         m_ptr = NULL;               \
  95         return ptr;                 \
  96     }                               \
  97                                     \
  98     T & operator*() const           \
  99     {                               \
 100         wxASSERT(m_ptr != NULL);    \
 101         return *m_ptr;              \
 102     }                               \
 103                                     \
 104     T * operator->() const          \
 105     {                               \
 106         wxASSERT(m_ptr != NULL);    \
 107         return m_ptr;               \
 108     }                               \
 109                                     \
 110     T * get() const                 \
 111     {                               \
 112         return m_ptr;               \
 113     }                               \
 114                                     \
 115     void swap(name & ot)            \
 116     {                               \
 117         T * tmp = ot.m_ptr;         \
 118         ot.m_ptr = m_ptr;           \
 119         m_ptr = tmp;                \
 120     }                               \
 121 };
 122
 123 #define wxDEFINE_SCOPED_PTR(T, name)\
 124 name::~name()                       \
 125 {                                   \
 126     wxCHECKED_DELETE(m_ptr);        \
 127 }
 128
 129 // this macro can be used for the most common case when you want to declare and
 130 // define the scoped pointer at the same time and want to use the standard
 131 // naming convention: auto pointer to Foo is called FooPtr
 132 #define wxDEFINE_SCOPED_PTR_TYPE(T)                                           \
 133     wxDECLARE_SCOPED_PTR(T, T ## Ptr);                                        \
 134     wxDEFINE_SCOPED_PTR(T, T ## Ptr)
 135
 136 // the same but for arrays instead of simple pointers
 137 #define wxDECLARE_SCOPED_ARRAY(T, name)\
 138 class name                          \
 139 {                                   \
 140 private:                            \
 141     T * m_ptr;                      \
 142     name(name const &);             \
 143     name & operator=(name const &); \
 144                                     \
 145 public:                             \
 146     wxEXPLICIT name(T * p = NULL) : m_ptr(p) \
 147     {}                              \
 148                                     \
 149     ~name();                        \
 150     void reset(T * p = NULL);       \
 151                                     \
 152     T & operator[](long int i) const\
 153     {                               \
 154         wxASSERT(m_ptr != NULL);    \
 155         wxASSERT(i >= 0);           \
 156         return m_ptr[i];            \
 157     }                               \
 158                                     \
 159     T * get() const                 \
 160     {                               \
 161         return m_ptr;               \
 162     }                               \
 163                                     \
 164     void swap(name & ot)            \
 165     {                               \
 166         T * tmp = ot.m_ptr;         \
 167         ot.m_ptr = m_ptr;           \
 168         m_ptr = tmp;                \
 169     }                               \
 170 };
 171
 172 #define wxDEFINE_SCOPED_ARRAY(T, name)  \
 173 name::~name()                           \
 174 {                                       \
 175     wxCHECKED_DELETE_ARRAY(m_ptr);      \
 176 }                                       \
 177 void name::reset(T * p){                \
 178     if (m_ptr != p)                     \
 179     {                                   \
 180        wxCHECKED_DELETE_ARRAY(m_ptr);   \
 181        m_ptr = p;                       \
 182     }                                   \
 183 }
 184
 185 // ----------------------------------------------------------------------------
 186 // "Tied" scoped pointer: same as normal one but also sets the value of
 187 //                        some other variable to the pointer value
 188 // ----------------------------------------------------------------------------
 189
 190 #define wxDEFINE_TIED_SCOPED_PTR_TYPE(T)                                      \
 191     wxDEFINE_SCOPED_PTR_TYPE(T);                                              \
 192     class T ## TiedPtr : public T ## Ptr                                      \
 193     {                                                                         \
 194     public:                                                                   \
 195         T ## TiedPtr(T **pp, T *p)                                            \
 196             : T ## Ptr(p), m_pp(pp)                                           \
 197         {                                                                     \
 198             m_pOld = *pp;                                                     \
 199             *pp = p;                                                          \
 200         }                                                                     \
 201                                                                               \
 202         ~ T ## TiedPtr()                                                      \
 203         {                                                                     \
 204             *m_pp = m_pOld;                                                   \
 205         }                                                                     \
 206                                                                               \
 207     private:                                                                  \
 208         T **m_pp;                                                             \
 209         T *m_pOld;                                                            \
 210     }
 211
 212 #endif // __WX_SCOPED_POINTER__
 213