Updates to Utilities

Utilities/Threading/CountdownLatch.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Threading;
+
+namespace Utilities
+{
+    public class CountdownLatch
+    {
+        private int m_count;
+        private EventWaitHandle m_waitHandle = new EventWaitHandle(true, EventResetMode.ManualReset);
+
+        public CountdownLatch()
+        {
+        }
+
+        public void Increment()
+        {
+            int count = Interlocked.Increment(ref m_count);
+            if (count == 1)
+            {
+                m_waitHandle.Reset();
+            }
+        }
+
+        public void Add(int value)
+        {
+            int count = Interlocked.Add(ref m_count, value);
+            if (count == value)
+            {
+                m_waitHandle.Reset();
+            }
+        }
+
+        public void Decrement()
+        {
+            int count = Interlocked.Decrement(ref m_count);
+            if (m_count == 0)
+            {
+                m_waitHandle.Set();
+            }
+            else if (count < 0)
+            {
+                throw new InvalidOperationException("Count must be greater than or equal to 0");
+            }
+        }
+
+        public void WaitUntilZero()
+        {
+            m_waitHandle.WaitOne();
+        }
+    }
+}