STARLIGHT/starlight/include/.svn/text-base/singleton.h.svn-base

   1 #ifndef SINGLETON_H
   2 #define SINGLETON_H
   3
   4 #ifdef CPP11
   5 #include <atomic>
   6 #include <mutex>
   7
   8
   9 template<class T>
  10 class Singleton {
  11 public:
  12   static T& instance()
  13   {
  14     T * tmp = instance_.load(std::memory_order_consume);
  15     if (!tmp) {
  16       std::lock_guard<std::mutex> guard(instantiation_mutex);
  17       tmp = instance_.load(std::memory_order_consume);
  18       if (!tmp) {
  19         tmp = new T;
  20         instance_.store(tmp, std::memory_order_release);
  21       }
  22     }
  23     return *tmp;
  24   }
  25 private:
  26   static std::atomic<T *> instance_;
  27   static std::mutex instantiation_mutex;
  28 };
  29
  30 template<class T>
  31 std::atomic<T *> Singleton<T>::instance_(0);
  32
  33 template<class T>
  34 std::mutex Singleton<T>::instantiation_mutex;
  35
  36 #else
  37
  38 #include "slmutex.h"
  39
  40 template<class T>
  41 class Singleton {
  42 public:
  43   static T& instance()
  44   {
  45     T *tmp = _instance;
  46     if (!tmp) {
  47       Lockguard<MutexPosix> guard(&_instantiation_mutex);
  48       if (!tmp) {
  49         tmp = new T;
  50         _instance = tmp;
  51       }
  52     }
  53     return *tmp;
  54   }
  55 private:
  56
  57   static T * _instance;
  58
  59   static MutexPosix _instantiation_mutex;
  60
  61 };
  62
  63 template<class T>
  64 T *Singleton<T>::_instance(0);
  65
  66 template<class T>
  67 MutexPosix Singleton<T>::_instantiation_mutex;
  68
  69 #endif
  70
  71 #endif
  72
  73