Modernize and simplify FastStack with a vector.

FastStack.h

@@ -6,36 +6,30 @@
 
 class FastStack {
 public:
-    FastStack(int size) : m_size(size), m_ptr(-1) {
-        m_stack = new PycRef<ASTNode>[m_size];
-    }
+    FastStack(int size) : m_ptr(-1) { m_stack.resize(size); }
 
-    FastStack(const FastStack& copy) : m_size(copy.m_size), m_ptr(copy.m_ptr) {
-        m_stack = new PycRef<ASTNode>[m_size];
+    FastStack(const FastStack& copy)
+        : m_stack(copy.m_stack), m_ptr(copy.m_ptr) { }
 
-        for (int i = 0; i <= m_ptr; i++)
-            m_stack[i] = copy.m_stack[i];
-    }
-
-    ~FastStack() {
-        delete[] m_stack;
-    }
-
-    FastStack& operator=(const FastStack& copy) {
-        replace(copy);
+    FastStack& operator=(const FastStack& copy)
+    {
+        m_stack = copy.m_stack;
+        m_ptr = copy.m_ptr;
         return *this;
     }
 
-    void push(PycRef<ASTNode> node) {
-        if (m_size == m_ptr + 1)
-            grow(1);
+    void push(PycRef<ASTNode> node)
+    {
+        if (static_cast<int>(m_stack.size()) == m_ptr + 1)
+            m_stack.emplace_back(nullptr);
 
-        m_stack[++m_ptr] = node;
+        m_stack[++m_ptr] = std::move(node);
     }
 
-    void pop() {
+    void pop()
+    {
         if (m_ptr > -1)
-            m_stack[m_ptr--] = NULL;
+            m_stack[m_ptr--] = nullptr;
     }
 
     PycRef<ASTNode> top() const
@@ -43,37 +37,12 @@ public:
         if (m_ptr > -1)
             return m_stack[m_ptr];
         else
-            return NULL;
-    }
-
-    void replace(const FastStack& copy)
-    {
-        if (&copy == this)
-            return;
-        delete[] m_stack;
-
-        m_size = copy.m_size;
-        m_ptr = copy.m_ptr;
-        m_stack = new PycRef<ASTNode>[m_size];
-        for (int i = 0; i <= m_ptr; i++)
-            m_stack[i] = copy.m_stack[i];
-    }
-
-    void grow(int inc)
-    {
-        m_size += inc;
-        PycRef<ASTNode>* tmp = new PycRef<ASTNode>[m_size];
-
-        for (int i = 0; i <= m_ptr; i++)
-            tmp[i] = m_stack[i];
-
-        delete[] m_stack;
-        m_stack = tmp;
+            return nullptr;
     }
 
 private:
-    PycRef<ASTNode>* m_stack;
-    int m_size, m_ptr;
+    std::vector<PycRef<ASTNode>> m_stack;
+    int m_ptr;
 };
 
 typedef std::stack<FastStack> stackhist_t;