1 files changed, 110 insertions, 0 deletions
diff --git a/csharp/src/ProtocolBuffers/Collections/Lists.cs b/csharp/src/ProtocolBuffers/Collections/Lists.cs
new file mode 100644
index 00000000..a24e1d9b
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+++ b/csharp/src/ProtocolBuffers/Collections/Lists.cs
@@ -0,0 +1,110 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://github.com/jskeet/dotnet-protobufs/
+// Original C++/Java/Python code:
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace Google.ProtocolBuffers.Collections
+{
+    /// <summary>
+    /// Utility non-generic class for calling into Lists{T} using type inference.
+    /// </summary>
+    public static class Lists
+    {
+        /// <summary>
+        /// Returns a read-only view of the specified list.
+        /// </summary>
+        public static IList<T> AsReadOnly<T>(IList<T> list)
+        {
+            return Lists<T>.AsReadOnly(list);
+        }
+
+        public static bool Equals<T>(IList<T> left, IList<T> right)
+        {
+            if (left == right)
+            {
+                return true;
+            }
+            if (left == null || right == null)
+            {
+                return false;
+            }
+            if (left.Count != right.Count)
+            {
+                return false;
+            }
+            IEqualityComparer<T> comparer = EqualityComparer<T>.Default;
+            for (int i = 0; i < left.Count; i++)
+            {
+                if (!comparer.Equals(left[i], right[i]))
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        public static int GetHashCode<T>(IList<T> list)
+        {
+            int hash = 31;
+            foreach (T element in list)
+            {
+                hash = hash*29 + element.GetHashCode();
+            }
+            return hash;
+        }
+    }
+
+    /// <summary>
+    /// Utility class for dealing with lists.
+    /// </summary>
+    public static class Lists<T>
+    {
+        private static readonly ReadOnlyCollection<T> empty = new ReadOnlyCollection<T>(new T[0]);
+
+        /// <summary>
+        /// Returns an immutable empty list.
+        /// </summary>
+        public static ReadOnlyCollection<T> Empty
+        {
+            get { return empty; }
+        }
+
+        /// <summary>
+        /// Returns either the original reference if it's already read-only,
+        /// or a new ReadOnlyCollection wrapping the original list.
+        /// </summary>
+        public static IList<T> AsReadOnly(IList<T> list)
+        {
+            return list.IsReadOnly ? list : new ReadOnlyCollection<T>(list);
+        }
+    }
+}
+\ No newline at end of file