instance_count.h

00001 ///\file
00002 
00003 /******************************************************************************
00004 The MIT License(MIT)
00005 
00006 Embedded Template Library.
00007 https://github.com/ETLCPP/etl
00008 http://www.etlcpp.com
00009 
00010 Copyright(c) 2014 jwellbelove
00011 
00012 Permission is hereby granted, free of charge, to any person obtaining a copy
00013 of this software and associated documentation files(the "Software"), to deal
00014 in the Software without restriction, including without limitation the rights
00015 to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
00016 copies of the Software, and to permit persons to whom the Software is
00017 furnished to do so, subject to the following conditions :
00018 
00019 The above copyright notice and this permission notice shall be included in all
00020 copies or substantial portions of the Software.
00021 
00022 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00023 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00024 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
00025 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00026 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00027 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00028 SOFTWARE.
00029 ******************************************************************************/
00030 
00031 #ifndef __ETL_INSTANCE_COUNT__
00032 #define __ETL_INSTANCE_COUNT__
00033 
00034 #include "platform.h "
00035 
00036 ///\defgroup instance_count instance count
00037 ///\ingroup utilities
00038 
00039 namespace etl
00040 {
00041   //***************************************************************************
00042   /// Inherit from this to count instances of a type.
00043   ///\ingroup reference
00044   //***************************************************************************
00045   template <typename T>
00046   class instance_count
00047   {
00048   public:
00049 
00050     //*************************************************************************
00051     /// Construct and add 1.
00052     //*************************************************************************
00053     instance_count()
00054     {
00055       ++how_many;
00056     }
00057 
00058     //*************************************************************************
00059     /// Destruct and subtract 1.
00060     //*************************************************************************
00061     virtual ~instance_count()
00062     {
00063       --how_many;
00064     }
00065 
00066     //*************************************************************************
00067     /// Get how many instances we have.
00068     //*************************************************************************
00069     inline static size_t get_instance_count()
00070     {
00071       return how_many;
00072     }
00073 
00074   private:
00075 
00076     /// The count for this type.
00077     static size_t how_many;
00078   };
00079 
00080   /// Initialisation.
00081   template <typename T> size_t instance_count<T>::how_many = 0;
00082 }
00083 
00084 #endif
00085 
00086