port from perforce

hgplus/bliss/Tweaky/SharedMemory.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.IO.MemoryMappedFiles;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Tweaky
+{
+    public class SharedMemory<T> where T : struct
+    {
+        // Constructor
+        public SharedMemory(string name, int size)
+        {
+            smName = name;
+            smSize = size;
+        }
+
+        // Methods
+        public bool Open()
+        {
+            try
+            {
+                // Create named MMF
+                mmf = MemoryMappedFile.CreateOrOpen(smName, smSize);
+
+                // Create accessors to MMF
+                accessor = mmf.CreateViewAccessor(0, smSize,
+                               MemoryMappedFileAccess.ReadWrite);
+
+                // Create lock
+                smLock = new Mutex(true, "SM_LOCK", out locked);
+            }
+            catch
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        public void Close()
+        {
+            accessor.Dispose();
+            mmf.Dispose();
+            smLock.Close();
+        }
+
+        public T Data
+        {
+            get
+            {
+                T dataStruct;
+                accessor.Read<T>(0, out dataStruct);
+                return dataStruct;
+            }
+            set
+            {
+                smLock.WaitOne();
+                accessor.Write<T>(0, ref value);
+                smLock.ReleaseMutex();
+            }
+        }
+
+        // Data
+        private string smName;
+        private Mutex smLock;
+        private int smSize;
+        private bool locked;
+        private MemoryMappedFile mmf;
+        private MemoryMappedViewAccessor accessor;
+    }
+}