everything compiles, now need to figure out ref counting

Makefile

@@ -1,3 +1,3 @@
 CXX=clang++
 test: SharedPtr_test.cpp SharedPtr.hpp
-	$(CXX) SharedPtr_test.cpp -o test
+	$(CXX) SharedPtr_test.cpp -Wall -fsanitize=address -g -o test

SharedPtr.hpp

@@ -9,51 +9,160 @@
 
 namespace cs440 {
 using counter = std::atomic<std::size_t>;
-template <typename T> class SharedPtr {
+class Control {
   counter count;
-  (???) underlying;
+
+  virtual void destroy() = 0;
 
 public:
+  Control() : count{1} {};
+  void decrement() {
+    count--;
+    if (count == 0) {
+      this->destroy();
+    }
+  }
+  void increment() { count++; }
+  virtual ~Control() = default;
+};
+template <typename T> class ControlImpl : public Control {
+  T *val;
+  void destroy() override {
+    delete val;
+    delete this;
+  }
+
+public:
+  ControlImpl(T *v) : Control{}, val{v} {}
+  ~ControlImpl() = default;
+};
+template <typename T> class SharedPtr {
+  T *raw;
+  Control *underlying;
+
+public:
+  template <typename U> friend class SharedPtr;
   // typename U meaning a type which inherits from T
-  SharedPtr();
+  SharedPtr() : raw{nullptr}, underlying{nullptr} {}
 
-  template <typename U> explicit SharedPtr(U *);
+  template <typename U> explicit SharedPtr(U *p) {
+    this->raw = p;
+    this->underlying = new ControlImpl<U>(p);
+  }
 
-  SharedPtr(const SharedPtr &p);
+  SharedPtr(const SharedPtr &p) : raw{p.raw}, underlying{p.underlying} {
-  template <typename U> SharedPtr(const SharedPtr<U> &p);
+    this->underlying->increment();
+  }
+  template <typename U>
+  SharedPtr(const SharedPtr<U> &p) : raw{p.raw}, underlying{p.underlying} {
+    this->underlying->increment();
+  }
 
-  SharedPtr(SharedPtr &&p);
+  SharedPtr(SharedPtr &&p) : raw{p.raw}, underlying{p.underlying} {
-  template <typename U> SharedPtr(SharedPtr<U> &&p);
+    p.raw = nullptr;
+    p.underlying = nullptr;
+  };
+  template <typename U>
+  SharedPtr(SharedPtr<U> &&p) : raw{p.raw}, underlying{p.underlying} {
+    p.raw = nullptr;
+    p.underlying = nullptr;
+  }
 
   // needs to handle self assignment
-  SharedPtr &operator=(const SharedPtr &);
+  SharedPtr &operator=(const SharedPtr &rhs) {
-  template <typename U> SharedPtr<T> &operator=(const SharedPtr<U> &);
+    if (this->underlying == rhs.underlying) {
+      return *this;
+    }
+    this->raw = rhs.raw;
+    this->underlying->decrement();
+    this->underlying = rhs.underlying;
+    this->underlying->increment();
+    return *this;
+  }
+  template <typename U> SharedPtr<T> &operator=(const SharedPtr<U> &rhs) {
+    if (this->underlying == rhs.underlying) {
+      return *this;
+    }
+    this->raw = rhs.raw;
+    this->underlying->decrement();
+    this->underlying = rhs.underlying;
+    this->underlying->increment();
+    return *this;
+  }
 
-  SharedPtr &operator=(SharedPtr &&p);
+  SharedPtr &operator=(SharedPtr &&rhs) {
-  template <typename U> SharedPtr &operator=(SharedPtr<U> &&p);
+    if (this == &rhs) {
-  ~SharedPtr();
+      return *this;
+    }
+    this->raw = rhs.raw;
+    this->underlying->decrement();
+    this->underlying = rhs.underlying;
+    rhs.raw = nullptr;
+    rhs.underlying = nullptr;
+  }
+  template <typename U> SharedPtr &operator=(SharedPtr<U> &&rhs) {
+    if (this == &rhs) {
+      return *this;
+    }
+    this->raw = rhs.raw;
+    this->underlying->decrement();
+    this->underlying = rhs.underlying;
+    rhs.raw = nullptr;
+    rhs.underlying = nullptr;
+  }
+  ~SharedPtr() { this->underlying->decrement(); }
 
   void reset() {
-    this->count = 0;
+    this->raw = nullptr;
+    if (this->underlying != nullptr) {
+      this->underlying->decrement();
+    }
     this->underlying = nullptr;
   }
-  template <typename U> void reset(U *p);
+  template <typename U> void reset(U *p) {
-  T *get() const;
+    this->raw = p;
+    if (this->underlying != nullptr) {
+      this->underlying->decrement();
+    }
+    this->underlying = new ControlImpl<U>(p);
+  }
+  T *get() const { return this->raw; }
   T &operator*() const { return *this->get(); }
   T *operator->() const { return this->get(); }
-  explicit operator bool() const;
+  explicit operator bool() const { return this->raw; }
-  template <typename T1, typename T2>
-  friend bool operator==(const SharedPtr<T1> &, const SharedPtr<T2> &);
-  friend bool operator==(const SharedPtr<T> &, std::nullptr_t);
-  friend bool operator==(std::nullptr_t, const SharedPtr<T> &);
-  template <typename T1, typename T2>
-  friend bool operator!=(const SharedPtr<T1> &, const SharedPtr<T2> &);
-  friend bool operator!=(const SharedPtr<T> &, std::nullptr_t);
-  friend bool operator!=(std::nullptr_t, const SharedPtr<T> &);
   template <typename U>
-  friend SharedPtr<T> static_pointer_cast(const SharedPtr<U> &sp);
+  friend bool operator==(const SharedPtr<T> &lhs, const SharedPtr<U> &rhs) {
+    return lhs.raw == rhs.raw;
+  }
+  friend bool operator==(const SharedPtr<T> &lhs, std::nullptr_t) {
+    return lhs.raw == nullptr;
+  }
+  friend bool operator==(std::nullptr_t, const SharedPtr<T> &rhs) {
+    return nullptr == rhs.raw;
+  }
+  // template <typename T1, typename T2>
+  // friend bool operator!=(const SharedPtr<T1> &lhs, const SharedPtr<T2> &rhs)
+  // {
+  //   return lhs.raw != rhs.raw;
+  // }
+  // friend bool operator!=(const SharedPtr<T> &lhs, std::nullptr_t) {
+  //   return lhs.raw != nullptr;
+  // }
+  // friend bool operator!=(std::nullptr_t, const SharedPtr<T> &rhs) {
+  //   return nullptr != rhs.raw;
+  // }
   template <typename U>
-  friend SharedPtr<T> dynamic_pointer_cast(const SharedPtr<U> &sp);
+  friend SharedPtr<T> static_pointer_cast(const SharedPtr<U> &sp) {
+    SharedPtr<T> ret{};
+    ret.raw = static_cast<T *>(sp.raw);
+    ret.underlying = sp.underlying;
+  }
+  template <typename U>
+  friend SharedPtr<T> dynamic_pointer_cast(const SharedPtr<U> &sp) {
+    SharedPtr<T> ret{};
+    ret.raw = dynamic_cast<T *>(sp.raw);
+    ret.underlying = sp.underlying;
+  }
 };
 } // namespace cs440
 #endif

SharedPtr_test.cpp

@@ -264,9 +264,9 @@ void basic_tests_1() {
       {
         SharedPtr<Derived> sp(new Derived);
         // Test template copy constructor.
-        // SharedPtr<Base1> sp3(sp);
+        SharedPtr<Base1> sp3(sp);
-        // sp2 = sp;
+        sp2 = sp;
-        // sp2 = sp2;
+        sp2 = sp2;
       }
     }
   }
@@ -279,7 +279,7 @@ void basic_tests_1() {
     }
     {
       SharedPtr<Derived> sp(new Derived);
-      // SharedPtr<Base1> sp2(sp);
+      SharedPtr<Base1> sp2(sp);
     }
   }
 
@@ -294,9 +294,9 @@ void basic_tests_1() {
     {
       SharedPtr<Derived> sp(new Derived);
       SharedPtr<Base1> sp2;
-      // sp2 = sp;
+      sp2 = sp;
       sp2 = sp2; // Self assignment.
-      // sp2 = sp;
+      sp2 = sp;
       sp = sp;
     }
   }
@@ -306,7 +306,7 @@ void basic_tests_1() {
     {
       SharedPtr<Derived> sp(new Derived);
       SharedPtr<Base1> sp2;
-      // sp2 = sp;
+      sp2 = sp;
       sp2 = sp2;
       sp.reset();
       sp.reset(new Derived);
@@ -339,10 +339,10 @@ void basic_tests_1() {
     SharedPtr<Derived> sp(new Derived);
     (*sp).value = 1234;
 
-    // SharedPtr<const Derived> sp2(sp);
+    SharedPtr<const Derived> sp2(sp);
-    // int i = (*sp2).value;
+    int i = (*sp2).value;
-    // assert(i == 1234);
+    assert(i == 1234);
-    //  (*sp2).value = 567; // Should give a syntax error if uncommented.
+    //(*sp2).value = 567; // Should give a syntax error if uncommented.
   }
 
   // Test ->.
@@ -350,9 +350,9 @@ void basic_tests_1() {
     SharedPtr<Derived> sp(new Derived);
     sp->value = 1234;
 
-    // SharedPtr<const Derived> sp2(sp);
+    SharedPtr<const Derived> sp2(sp);
-    // int i = sp2->value;
+    int i = sp2->value;
-    // assert(i == 1234);
+    assert(i == 1234);
     //  sp2->value = 567; // Should give a syntax error if uncommented.
   }
 
@@ -361,9 +361,9 @@ void basic_tests_1() {
     SharedPtr<Derived> sp(new Derived);
     sp.get()->value = 1234;
 
-    // SharedPtr<const Derived> sp2(sp);
+    SharedPtr<const Derived> sp2(sp);
-    // int i = sp2.get()->value;
+    int i = sp2.get()->value;
-    // assert(i == 1234);
+    assert(i == 1234);
   }
 
   // Test bool.