Imported Upstream version 1.1.0upstream/1.1.0

1 files changed, 87 insertions, 0 deletions

diff --git a/src/inc/stack.h b/src/inc/stack.h
new file mode 100644
index 0000000000..589f8f7766
--- /dev/null
+++ b/src/inc/stack.h
@@ -0,0 +1,87 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+//----------------------------------------------------------------------------- 
+
+//----------------------------------------------------------------------------- 
+// This is a generic growable stack of T.
+
+#ifndef GENERIC_STACK_H
+#define GENERIC_STACK_H 1
+
+#include <math.h>
+
+template<typename T>
+class Stack
+{
+    T* m_elems;
+    unsigned m_elemsSize;
+    unsigned m_elemsCount;
+
+    static const unsigned InitSize = 8;
+
+    void GrowForPush()
+    {
+        if (m_elemsCount == m_elemsSize)
+        {
+            m_elemsSize = max(InitSize, 2*m_elemsSize);
+            T* newElems = new T[m_elemsSize];
+            if (m_elemsCount != 0)
+            {
+                _ASSERTE(m_elems != NULL);
+                for (unsigned k = 0; k < m_elemsCount; k++) newElems[k] = m_elems[k];
+                delete[] m_elems;
+            }
+            m_elems = newElems;
+        }
+    }
+
+  public:
+    Stack(unsigned sz = 0) : m_elems(NULL), m_elemsSize(sz), m_elemsCount(0)
+    {
+        if (sz > 0)
+        {
+            m_elems = new T[sz];
+        }
+    }
+
+    ~Stack()
+    {
+        if (m_elems != NULL) delete[] m_elems;
+    }
+
+    void Push(T t)
+    {
+        GrowForPush();
+        m_elems[m_elemsCount] = t;
+        m_elemsCount++;
+    }
+
+    bool IsEmpty()
+    {
+        return m_elemsCount == 0;
+    }
+
+    T Pop()
+    {
+        _ASSERTE(m_elemsCount > 0);
+        m_elemsCount--;
+        return m_elems[m_elemsCount];
+    }
+
+    T Peek()
+    {
+        _ASSERTE(m_elemsCount > 0);
+        return m_elems[m_elemsCount-1];
+    }
+
+    // Caller should take care to only side-effect the return reference if he/she is *sure*
+    // that the stack will not be popped in the interim!
+    T& PeekRef()
+    {
+        _ASSERTE(m_elemsCount > 0);
+        return m_elems[m_elemsCount-1];
+    }
+};
+
+#endif // GENERIC_STACK_H