shared_ptr

1 files changed, 202 insertions, 28 deletions

diff --git a/ue5/shared_ptr.hpp b/ue5/shared_ptr.hpp
index 4492fff..00a4dc7 100644
--- a/ue5/shared_ptr.hpp
+++ b/ue5/shared_ptr.hpp
@@ -4,80 +4,254 @@
 /* TODO includes */
 
 #undef SOLVED_1
-//#define SOLVED_1
+#define SOLVED_1
 
-namespace Ti {
+/* TODO: remove */
+#define SHPDEBUG if (0)
+#include <iostream>
 
+namespace Ti
+{
   /* TODO helpers */
 
   template <typename T>
     class shared_ptr
     {
       private:
-        /* TODO data */
+        T* m_ptr;
+        unsigned long* m_count;
 
       public:
-        shared_ptr();
-        T* get() const;
-        shared_ptr (const shared_ptr<T>& other);
+        shared_ptr()
+          : m_ptr(NULL), m_count(NULL)
+        {
+          SHPDEBUG std::cerr << this << ": shared_ptr()" << std::endl;
+        }
 
+        T* get() const
+        {
+          SHPDEBUG std::cerr << this << ": get()" << std::endl;
+          return m_ptr;
+        }
+
+        shared_ptr(const shared_ptr<T>& other)
+          : m_ptr(other.m_ptr), m_count(other.m_count)
+        {
+          SHPDEBUG std::cerr << this << ": shared_ptr(shared_ptr<T>& other)" << std::endl;
+          add_ref();
+        }
+
+        template <typename O>
+          shared_ptr(const shared_ptr<O>& other)
+            : m_ptr(other.m_ptr), m_count(other.m_count)
+          {
+            SHPDEBUG std::cerr << this << ": shared_ptr(shared_ptr<O>& other)" << std::endl;
+            add_ref();
+          }
+
+        /* used to construct shared_ptr with a sub-object of O */
         template <typename O>
-          shared_ptr (const shared_ptr<O>& other);
+          shared_ptr(const shared_ptr<O>& other, T* ptr)
+            : m_ptr(ptr), m_count(other.m_count)
+          {
+            SHPDEBUG std::cerr << this << ": shared_ptr(shared_ptr<O>& other, O* ptr)" << std::endl;
+            add_ref();
+          }
 
         template <typename O>
-          explicit shared_ptr (O* p);
-        shared_ptr& operator = (const shared_ptr<T>& other);
+          explicit shared_ptr(O* p)
+          : m_ptr(p), m_count(new unsigned long(1))
+          {
+            SHPDEBUG std::cerr << this << ": shared_ptr(O* p)" << std::endl;
+          }
+
+        shared_ptr& operator=(const shared_ptr<T>& other)
+        {
+          SHPDEBUG std::cerr << this << ": operator=(shared_ptr<T>& other)" << std::endl;
+#if 1
+          shared_ptr(other).swap(*this);
+          return *this;
+#else
+          if (*this == other)
+            return *this;
+
+          release();
+
+          m_ptr = other.m_ptr;
+          m_count = other.m_count;
+          add_ref();
+          return *this;
+#endif
+        }
 
         template <typename O>
-          shared_ptr& operator = (const shared_ptr<O>& other);
+          shared_ptr& operator=(const shared_ptr<O>& other)
+        {
+          SHPDEBUG std::cerr << this << ": operator=(shared_ptr<O>& other)" << std::endl;
+#if 0
+          shared_ptr(other).swap(*this);
+          return *this;
+#else
+          if (*this == other)
+            return *this;
 
-        ~shared_ptr ();
-        T& operator * () const;
-        T* operator -> () const;
+          release();
 
-        void swap (shared_ptr<T>& other);
+          m_ptr = other.m_ptr;
+          m_count = other.m_count;
+          add_ref();
+          return *this;
+#endif
+        }
+
+        ~shared_ptr()
+        {
+          SHPDEBUG std::cerr << this << ": ~shared_ptr()" << std::endl;
+          release();
+        }
+
+        T& operator*() const
+        {
+          return *m_ptr;
+        }
+
+        T* operator->() const
+        {
+          return m_ptr;
+        }
 
-        inline void reset();
+        void swap(shared_ptr<T>& other)
+        {
+          /* std::swap(m_ptr, other.m_ptr); */
+          T* ptr(m_ptr);
+          m_ptr = other.m_ptr;
+          other.m_ptr = ptr;
+
+          /* std::swap(m_count, other.m_count); */
+          unsigned long* count(m_count);
+          m_count = other.m_count;
+          other.m_count = count;
+        }
+
+        inline void reset()
+        {
+          shared_ptr().swap(*this);
+        }
 
       private:
+        void add_ref()
+        {
+          if (m_count != NULL)
+            ++(*m_count);
+        }
+
+        void release()
+        {
+          if (m_ptr != NULL)
+          {
+            --(*m_count);
+            if (*m_count == 0)
+            {
+              delete m_ptr;
+              delete m_count;
+            }
+          }
+        }
+
+        template<class O> friend class shared_ptr;
+
         template <typename R, typename... Args>
-          friend shared_ptr<R> make_shared (Args...);
+          friend shared_ptr<R> make_shared(Args...);
 
         template<typename U1, typename U2>
-          friend bool operator == (const shared_ptr<U1>& a, const shared_ptr<U2>& b);
+          friend bool operator==(const shared_ptr<U1>& a, const shared_ptr<U2>& b);
 
         template<typename U1, typename U2>
-          friend bool operator == (const shared_ptr<U1>& a, const U2* b);
+          friend bool operator==(const shared_ptr<U1>& a, const U2* b);
 
         template<typename U1, typename U2>
-          friend bool operator == (const U1* a, const shared_ptr<U2>& b);
+          friend bool operator==(const U1* a, const shared_ptr<U2>& b);
 
         template<typename U1, typename U2>
-          friend bool operator != (const shared_ptr<U1>& a, const U2* b);
+          friend bool operator!=(const shared_ptr<U1>& a, const U2* b);
 
         template<typename U1, typename U2>
-          friend bool operator != (const U1* a, const shared_ptr<U2>& b);
+          friend bool operator!=(const U1* a, const shared_ptr<U2>& b);
 
         template<typename U1, typename U2>
-          friend bool operator != (const shared_ptr<U1>& a, const shared_ptr<U2>& b);
+          friend bool operator!=(const shared_ptr<U1>& a, const shared_ptr<U2>& b);
 
         template <typename R, typename F>
-          friend shared_ptr<R> shared_dynamic_cast (const shared_ptr<F>& from);
+          friend shared_ptr<R> shared_dynamic_cast(const shared_ptr<F>& from);
     };
 
+  template <typename T, typename ... Args>
+    shared_ptr<T> make_shared(Args ... args)
+    {
+      SHPDEBUG std::cerr << "make_shared(args...)" << std::endl;
+      return shared_ptr<T>(new T(args ...));
+    }
+
+  template<typename U1, typename U2>
+    bool operator==(const shared_ptr<U1>& a, const shared_ptr<U2>& b)
+    {
+      return a.get() == b.get();
+    }
+
+  template<typename U1, typename U2>
+    bool operator==(const shared_ptr<U1>& a, const U2* b)
+    {
+      return a.get() == b.get();
+    }
+
+  template<typename U1, typename U2>
+    bool operator==(const U1* a, const shared_ptr<U2>& b)
+    {
+      return a.get() == b.get();
+    }
+
+  template<typename U1, typename U2>
+    bool operator!=(const shared_ptr<U1>& a, const U2* b)
+    {
+      return a.get() != b.get();
+    }
+
+  template<typename U1, typename U2>
+    bool operator!=(const U1* a, const shared_ptr<U2>& b)
+    {
+      return a.get() != b.get();
+    }
 
-  template <typename T /* TODO */ >
-    shared_ptr<T> make_shared (/* TODO */);
+  template<typename U1, typename U2>
+    bool operator!=(const shared_ptr<U1>& a, const shared_ptr<U2>& b)
+    {
+      return a.get() != b.get();
+    }
 
   template <typename T, typename F>
-    shared_ptr<T> shared_dynamic_cast (const shared_ptr<F>& from);
+    shared_ptr<T> shared_dynamic_cast(const shared_ptr<F>& from)
+    {
+      SHPDEBUG std::cerr << "shared_dynamic_cast(...)" << std::endl;
+      T* castptr = dynamic_cast<T *>(from.get());
+      if (castptr != NULL)
+      {
+        return shared_ptr<T>(from, castptr);
+      }
+      else
+        return shared_ptr<T>();
+    }
 
 } // end namespace ti
 
-namespace std {
+namespace std
+{
   using namespace Ti;
   template <typename T>
-    inline void swap (shared_ptr<T>& t1, shared_ptr<T>& t2);
+    inline void swap(shared_ptr<T>& t1, shared_ptr<T>& t2)
+    {
+      t1.swap(t2);
+    }
+
   /* TODO */
 }