1 files changed, 57 insertions, 0 deletions
diff --git a/src/mscorlib/src/System/UnSafeCharBuffer.cs b/src/mscorlib/src/System/UnSafeCharBuffer.cs
new file mode 100644
index 0000000000..78059b623a
--- /dev/null
+++ b/src/mscorlib/src/System/UnSafeCharBuffer.cs
@@ -0,0 +1,57 @@
+// 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.
+
+/*============================================================
+**
+**
+** Purpose: A class to detect incorrect usage of UnSafeBuffer
+**
+** 
+===========================================================*/
+
+namespace System {
+    using System.Security;
+    using System.Diagnostics;
+    using System.Diagnostics.Contracts;
+    
+    unsafe internal struct UnSafeCharBuffer{
+        [SecurityCritical]
+        char * m_buffer;
+        int m_totalSize;
+        int m_length;    
+    
+        [System.Security.SecurityCritical]  // auto-generated
+        public UnSafeCharBuffer( char *buffer,  int bufferSize) {
+            Contract.Assert( buffer != null, "buffer pointer can't be null."  );
+            Contract.Assert( bufferSize >= 0, "buffer size can't be negative."  );        
+            m_buffer = buffer;
+            m_totalSize = bufferSize;    
+            m_length = 0;
+        }
+    
+        [System.Security.SecuritySafeCritical]  // auto-generated
+        public void AppendString(string stringToAppend) {
+            if( String.IsNullOrEmpty( stringToAppend ) ) {
+                return;
+            }
+            
+            if ( (m_totalSize - m_length) < stringToAppend.Length ) {
+                throw new IndexOutOfRangeException();
+            }
+            
+            fixed( char* pointerToString = stringToAppend ) {        
+                Buffer.Memcpy( (byte*) (m_buffer + m_length), (byte *) pointerToString, stringToAppend.Length * sizeof(char));
+            }    
+            
+            m_length += stringToAppend.Length;
+            Contract.Assert(m_length <= m_totalSize, "Buffer has been overflowed!");
+        }
+                
+        public int Length {
+            get {
+                return m_length;
+            } 
+        }   
+    }    
+}