adding source code files

labs/13_smart_memory/ds_smart_pointers.h

@@ -0,0 +1,77 @@
+#include <cstdlib>
+
+// ==============================================================================
+// basic auto pointer implementation
+// see also http://ootips.org/yonat/4dev/smart-pointers.html
+
+template <class T>
+class dsAutoPtr {
+public:
+  explicit dsAutoPtr(T* p = NULL) : ptr(p) {}  /* prevents cast/conversion */
+  ~dsAutoPtr()      { delete ptr; }
+  T& operator*()   { return *ptr; }
+  T* operator->()  { return ptr; }
+private:
+  T* ptr;
+};
+
+
+// ==============================================================================
+// basic reference counting pointer borrowed from:
+// http://www.codeproject.com/Articles/15351/Implementing-a-simple-smart-pointer-in-c
+
+class ReferenceCount {
+public:
+  ReferenceCount() { count = 0; }
+  void addReference() { count++; }
+  int releaseReference() { return --count; }
+private:
+  int count; 
+};
+
+
+template <class T> 
+class dsSharedPtr {
+public:
+  dsSharedPtr(T* pValue = NULL) : pData(pValue) {
+    // Create a new reference counter & increment the count
+    reference = new ReferenceCount();
+    reference->addReference();
+  }
+  dsSharedPtr(const dsSharedPtr<T>& sp) : pData(sp.pData), reference(sp.reference) {
+    // use the same reference counter, increment the count
+    reference->addReference();
+  }
+  dsSharedPtr<T>& operator= (const dsSharedPtr<T>& sp) {
+    if (this != &sp) {
+      // Decrement the old reference count
+      // if reference become zero delete the old data
+      if(reference->releaseReference() == 0) {
+        delete pData;
+        delete reference;
+      }
+      // Copy the data and reference pointer
+      // and increment the reference count
+      pData = sp.pData;
+      reference = sp.reference;
+      reference->addReference();
+    }
+    return *this;
+  }
+  // destructor
+  ~dsSharedPtr() {
+    if (reference->releaseReference() == 0) {
+      delete pData;
+      delete reference;
+    }
+  }
+  bool operator== (const dsSharedPtr<T>& sp) { return pData == sp.pData; }
+  T& operator* () { return *pData; }
+  T* operator-> () { return pData; }
+private:
+  // REPRESENTATION
+  T*    pData;  
+  ReferenceCount* reference; 
+};
+
+// ==============================================================================