src/core/pointer.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD 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, version 2.
   4  * OpenTTD 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.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file pointer.h Smart pointer types. */
   9
  10 #ifndef POINTER_H
  11 #define POINTER_H
  12
  13 #include <cstdlib>
  14
  15 /*
  16  * Alias a number of smart pointer types to our own custom names, depending
  17  * on the actual types provided by the implementation:
  18  * * ttd_shared_ptr is aliased to std::shared_ptr.
  19  * * ttd_unique_ptr is aliased to std::unique_ptr if available, else to
  20  *   ttd_shared_ptr (as a consequence, ttd_unique_ptr can only be used with
  21  *   one template argument, not two).
  22  * * ttd_unique_free_ptr is an implementation of a ttd_unique_ptr (possibly
  23  *   through ttd_shared_ptr) that frees (not deletes) its managed pointer
  24  *   on destruction.
  25  */
  26
  27
  28 #ifdef __GNUC__
  29 # if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
  30 #  include <memory>
  31 #  define ttd_shared_ptr std::shared_ptr
  32 #  define ttd_unique_ptr std::unique_ptr
  33 #  define TTD_UNIQUE_PTR_USABLE 1
  34 # else
  35 #  include <tr1/memory>
  36 #  define ttd_shared_ptr std::tr1::shared_ptr
  37 #  define ttd_unique_ptr ttd_shared_ptr
  38 #  define TTD_UNIQUE_PTR_USABLE 0
  39 # endif
  40 #endif /* __GNUC__ */
  41
  42
  43 #ifdef _MSC_VER
  44 # include <memory>
  45 # if _MSC_VER < 1600
  46 #  define ttd_shared_ptr std::tr1::shared_ptr
  47 #  define ttd_unique_ptr ttd_shared_ptr
  48 # else
  49 #  define ttd_shared_ptr std::shared_ptr
  50 #  define ttd_unique_ptr std::unique_ptr
  51 # endif
  52 /* Trying to derive from std::unique_ptr results in MSVC complaining that it
  53  * cannot generate the default copy constructor for the derived class. */
  54 # define TTD_UNIQUE_PTR_USABLE 0
  55 #endif /* _MSC_VER */
  56
  57
  58 #if TTD_UNIQUE_PTR_USABLE
  59
  60 struct ttd_delete_free {
  61         void operator() (void *p) { free(p); }
  62 };
  63
  64 template <typename T>
  65 struct ttd_unique_free_ptr : ttd_unique_ptr <T, ttd_delete_free> {
  66         CONSTEXPR ttd_unique_free_ptr()
  67                 : ttd_unique_ptr <T, ttd_delete_free> () { }
  68
  69         explicit ttd_unique_free_ptr (T *t)
  70                 : ttd_unique_ptr <T, ttd_delete_free> (t) { }
  71 };
  72
  73 #else
  74
  75 template <typename T>
  76 struct ttd_unique_free_ptr : ttd_shared_ptr <T> {
  77         /* Using free directly as deleter requires a cast for overload
  78          * resolution, and that seems to cause calling convention confusion
  79          * in MSVC, so we use this proxy function. */
  80         static void ttd_free (void *p)
  81         {
  82                 free (p);
  83         }
  84
  85         CONSTEXPR ttd_unique_free_ptr() : ttd_shared_ptr <T> () { }
  86
  87         explicit ttd_unique_free_ptr (T *t) : ttd_shared_ptr <T> (t, ttd_free)
  88         {
  89         }
  90
  91         void reset (void)
  92         {
  93                 ttd_shared_ptr<T>::reset();
  94         }
  95
  96         template <typename TT>
  97         void reset (TT *p)
  98         {
  99                 ttd_shared_ptr<T>::reset (p, ttd_free);
 100         }
 101 };
 102
 103 #endif
 104
 105
 106 #endif /* POINTER_H */