Tidying up and extra tests.

This is mostly just making things internal instead of public, removing and reordering a bunch of code in CodedInputStream/CodedOutputStream, and generally tidying up.

csharp/src/ProtocolBuffers.Test/CodedInputStreamExtensions.cs

@@ -0,0 +1,54 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+#endregion
+
+using NUnit.Framework;
+
+namespace Google.Protobuf
+{
+    internal static class CodedInputStreamExtensions
+    {
+        public static void AssertNextTag(this CodedInputStream input, uint expectedTag)
+        {
+            uint tag;
+            Assert.IsTrue(input.ReadTag(out tag));
+            Assert.AreEqual(expectedTag, tag);
+        }
+
+        public static T ReadMessage<T>(this CodedInputStream stream, MessageParser<T> parser)
+            where T : IMessage<T>
+        {
+            var message = parser.CreateTemplate();
+            stream.ReadMessage(message);
+            return message;
+        }
+    }
+}

csharp/src/ProtocolBuffers.Test/CodedInputStreamTest.cs

@@ -35,10 +35,8 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.IO;
 using Google.Protobuf.Collections;
-using Google.Protobuf.Descriptors;
 using Google.Protobuf.TestProtos;
 using NUnit.Framework;
 
@@ -62,7 +60,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Parses the given bytes using ReadRawVarint32() and ReadRawVarint64() and
+        /// Parses the given bytes using ReadRawVarint32() and ReadRawVarint64()
         /// </summary>
         private static void AssertReadVarint(byte[] data, ulong value)
         {
@@ -232,66 +230,26 @@ namespace Google.Protobuf
             Assert.AreEqual(0x7FFFFFFFFFFFFFFFL, CodedInputStream.DecodeZigZag64(0xFFFFFFFFFFFFFFFEL));
             Assert.AreEqual(unchecked((long) 0x8000000000000000L), CodedInputStream.DecodeZigZag64(0xFFFFFFFFFFFFFFFFL));
         }
-        /*
+        
         [Test]
-        public void ReadWholeMessage()
+        public void ReadWholeMessage_VaryingBlockSizes()
         {
-            TestAllTypes message = TestUtil.GetAllSet();
+            TestAllTypes message = GeneratedMessageTest.GetSampleMessage();
 
             byte[] rawBytes = message.ToByteArray();
-            Assert.AreEqual(rawBytes.Length, message.SerializedSize);
-            TestAllTypes message2 = TestAllTypes.ParseFrom(rawBytes);
-            TestUtil.AssertAllFieldsSet(message2);
+            Assert.AreEqual(rawBytes.Length, message.CalculateSize());
+            TestAllTypes message2 = TestAllTypes.Parser.ParseFrom(rawBytes);
+            Assert.AreEqual(message, message2);
 
             // Try different block sizes.
             for (int blockSize = 1; blockSize < 256; blockSize *= 2)
             {
-                message2 = TestAllTypes.ParseFrom(new SmallBlockInputStream(rawBytes, blockSize));
-                TestUtil.AssertAllFieldsSet(message2);
+                message2 = TestAllTypes.Parser.ParseFrom(new SmallBlockInputStream(rawBytes, blockSize));
+                Assert.AreEqual(message, message2);
             }
         }
-
+                
         [Test]
-        public void SkipWholeMessage()
-        {
-            TestAllTypes message = TestUtil.GetAllSet();
-            byte[] rawBytes = message.ToByteArray();
-
-            // Create two parallel inputs.  Parse one as unknown fields while using
-            // skipField() to skip each field on the other.  Expect the same tags.
-            CodedInputStream input1 = CodedInputStream.CreateInstance(rawBytes);
-            CodedInputStream input2 = CodedInputStream.CreateInstance(rawBytes);
-            UnknownFieldSet.Builder unknownFields = UnknownFieldSet.CreateBuilder();
-
-            uint tag;
-            string name;
-            while (input1.ReadTag(out tag, out name))
-            {
-                uint tag2;
-                Assert.IsTrue(input2.ReadTag(out tag2, out name));
-                Assert.AreEqual(tag, tag2);
-
-                unknownFields.MergeFieldFrom(tag, input1);
-                input2.SkipField();
-            }
-        }*/
-
-        /// <summary>
-        /// Test that a bug in SkipRawBytes has been fixed: if the skip
-        /// skips exactly up to a limit, this should bnot break things
-        /// </summary>
-        [Test]
-        public void SkipRawBytesBug()
-        {
-            byte[] rawBytes = new byte[] {1, 2};
-            CodedInputStream input = CodedInputStream.CreateInstance(rawBytes);
-
-            int limit = input.PushLimit(1);
-            input.SkipRawBytes(1);
-            input.PopLimit(limit);
-            Assert.AreEqual(2, input.ReadRawByte());
-        }
-        /*
         public void ReadHugeBlob()
         {
             // Allocate and initialize a 1MB blob.
@@ -302,24 +260,15 @@ namespace Google.Protobuf
             }
 
             // Make a message containing it.
-            TestAllTypes.Builder builder = TestAllTypes.CreateBuilder();
-            TestUtil.SetAllFields(builder);
-            builder.SetOptionalBytes(ByteString.CopyFrom(blob));
-            TestAllTypes message = builder.Build();
+            var message = new TestAllTypes { SingleBytes = ByteString.CopyFrom(blob) };
 
             // Serialize and parse it.  Make sure to parse from an InputStream, not
             // directly from a ByteString, so that CodedInputStream uses buffered
             // reading.
-            TestAllTypes message2 = TestAllTypes.ParseFrom(message.ToByteString().CreateCodedInput());
+            TestAllTypes message2 = TestAllTypes.Parser.ParseFrom(message.ToByteString());
 
-            Assert.AreEqual(message.OptionalBytes, message2.OptionalBytes);
-
-            // Make sure all the other fields were parsed correctly.
-            TestAllTypes message3 = TestAllTypes.CreateBuilder(message2)
-                .SetOptionalBytes(TestUtil.GetAllSet().OptionalBytes)
-                .Build();
-            TestUtil.AssertAllFieldsSet(message3);
-        }*/
+            Assert.AreEqual(message, message2);
+        }
 
         [Test]
         public void ReadMaliciouslyLargeBlob()
@@ -461,85 +410,15 @@ namespace Google.Protobuf
             }
         }
 
-        enum TestNegEnum { None = 0, Value = -2 }
-
         [Test]
         public void TestNegativeEnum()
         {
-            byte[] bytes = new byte[10] { 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01 };
+            byte[] bytes = { 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01 };
             CodedInputStream input = CodedInputStream.CreateInstance(bytes);
-            Assert.AreEqual((int)TestNegEnum.Value, input.ReadEnum());
+            Assert.AreEqual((int)SampleEnum.NegativeValue, input.ReadEnum());
             Assert.IsTrue(input.IsAtEnd);
         }
 
-        [Test]
-        public void TestNegativeEnumPackedArray()
-        {
-            int arraySize = 1 + (10 * 5);
-            int msgSize = 1 + 1 + arraySize;
-            byte[] bytes = new byte[msgSize];
-            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
-            // Length-delimited to show we want the packed representation
-            uint tag = WireFormat.MakeTag(8, WireFormat.WireType.LengthDelimited);
-            output.WriteTag(tag);
-            int size = 0;
-            for (int i = 0; i >= -5; i--)
-            {
-                size += CodedOutputStream.ComputeEnumSize(i);
-            }
-            output.WriteRawVarint32((uint) size);
-            for (int i = 0; i >= -5; i--)
-            {
-                output.WriteEnum(i);
-            }
-            Assert.AreEqual(0, output.SpaceLeft);
-
-            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
-            Assert.IsTrue(input.ReadTag(out tag));
-
-            RepeatedField<TestNegEnum> values = new RepeatedField<TestNegEnum>();
-            values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int) x, x => (TestNegEnum) x));
-
-            Assert.AreEqual(6, values.Count);
-            Assert.AreEqual(TestNegEnum.None, values[0]);
-            Assert.AreEqual(((TestNegEnum) (-1)), values[1]);
-            Assert.AreEqual(TestNegEnum.Value, values[2]);
-            Assert.AreEqual(((TestNegEnum)(-3)), values[3]);
-            Assert.AreEqual(((TestNegEnum)(-4)), values[4]);
-            Assert.AreEqual(((TestNegEnum)(-5)), values[5]);
-        }
-
-        [Test]
-        public void TestNegativeEnumArray()
-        {
-            int arraySize = 1 + 1 + (11 * 5);
-            int msgSize = arraySize;
-            byte[] bytes = new byte[msgSize];
-            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
-            uint tag = WireFormat.MakeTag(8, WireFormat.WireType.Varint);
-            for (int i = 0; i >= -5; i--)
-            {
-                output.WriteTag(tag);
-                output.WriteEnum(i);
-            }
-
-            Assert.AreEqual(0, output.SpaceLeft);
-
-            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
-            Assert.IsTrue(input.ReadTag(out tag));
-
-            RepeatedField<TestNegEnum> values = new RepeatedField<TestNegEnum>();
-            values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (TestNegEnum)x));
-
-            Assert.AreEqual(6, values.Count);
-            Assert.AreEqual(TestNegEnum.None, values[0]);
-            Assert.AreEqual(((TestNegEnum)(-1)), values[1]);
-            Assert.AreEqual(TestNegEnum.Value, values[2]);
-            Assert.AreEqual(((TestNegEnum)(-3)), values[3]);
-            Assert.AreEqual(((TestNegEnum)(-4)), values[4]);
-            Assert.AreEqual(((TestNegEnum)(-5)), values[5]);
-        }
-
         //Issue 71:	CodedInputStream.ReadBytes go to slow path unnecessarily
         [Test]
         public void TestSlowPathAvoidance()

csharp/src/ProtocolBuffers.Test/CodedOutputStreamTest.cs

@@ -35,9 +35,8 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.IO;
-using Google.Protobuf.Collections;
+using Google.Protobuf.TestProtos;
 using NUnit.Framework;
 
 namespace Google.Protobuf
@@ -195,42 +194,24 @@ namespace Google.Protobuf
                 0x9abcdef012345678UL);
         }
 
-        /*
         [Test]
-        public void WriteWholeMessage()
+        public void WriteWholeMessage_VaryingBlockSizes()
         {
-            TestAllTypes message = TestUtil.GetAllSet();
+            TestAllTypes message = GeneratedMessageTest.GetSampleMessage();
 
             byte[] rawBytes = message.ToByteArray();
-            TestUtil.AssertEqualBytes(TestUtil.GoldenMessage.ToByteArray(), rawBytes);
 
             // Try different block sizes.
             for (int blockSize = 1; blockSize < 256; blockSize *= 2)
             {
                 MemoryStream rawOutput = new MemoryStream();
-                CodedOutputStream output =
-                    CodedOutputStream.CreateInstance(rawOutput, blockSize);
+                CodedOutputStream output = CodedOutputStream.CreateInstance(rawOutput, blockSize);
                 message.WriteTo(output);
                 output.Flush();
-                TestUtil.AssertEqualBytes(rawBytes, rawOutput.ToArray());
+                Assert.AreEqual(rawBytes, rawOutput.ToArray());
             }
         }
-
-        /// <summary>
-        /// Tests writing a whole message with every packed field type. Ensures the
-        /// wire format of packed fields is compatible with C++.
-        /// </summary>
-        [Test]
-        public void WriteWholePackedFieldsMessage()
-        {
-            TestPackedTypes message = TestUtil.GetPackedSet();
-
-            byte[] rawBytes = message.ToByteArray();
-            TestUtil.AssertEqualBytes(TestUtil.GetGoldenPackedFieldsMessage().ToByteArray(),
-                                      rawBytes);
-        }
-        */
-
+        
         [Test]
         public void EncodeZigZag32()
         {
@@ -296,68 +277,16 @@ namespace Google.Protobuf
         public void TestNegativeEnumNoTag()
         {
             Assert.AreEqual(10, CodedOutputStream.ComputeInt32Size(-2));
-            Assert.AreEqual(10, CodedOutputStream.ComputeEnumSize((int) TestNegEnum.Value));
+            Assert.AreEqual(10, CodedOutputStream.ComputeEnumSize((int) SampleEnum.NegativeValue));
 
             byte[] bytes = new byte[10];
             CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
-            output.WriteEnum((int) TestNegEnum.Value);
+            output.WriteEnum((int) SampleEnum.NegativeValue);
 
             Assert.AreEqual(0, output.SpaceLeft);
             Assert.AreEqual("FE-FF-FF-FF-FF-FF-FF-FF-FF-01", BitConverter.ToString(bytes));
         }
 
-        enum TestNegEnum { None = 0, Value = -2 }
-
-        /*
-        [Test]
-        public void TestNegativeEnumArrayPacked()
-        {
-            int arraySize = 1 + (10 * 5);
-            int msgSize = 1 + 1 + arraySize;
-            byte[] bytes = new byte[msgSize];
-            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
-            output.WriteTag(8, WireFormat.WireType.LengthDelimited);
-            output.WritePackedEnumArray(new RepeatedField<TestNegEnum> {
-                0, (TestNegEnum) (-1), TestNegEnum.Value, (TestNegEnum) (-3), (TestNegEnum) (-4), (TestNegEnum) (-5) });
-
-            Assert.AreEqual(0, output.SpaceLeft);
-
-            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
-            uint tag;
-            Assert.IsTrue(input.ReadTag(out tag));
-
-            List<int> values = new List<int>();
-            input.ReadInt32Array(values);
-
-            Assert.AreEqual(6, values.Count);
-            for (int i = 0; i > -6; i--)
-                Assert.AreEqual(i, values[Math.Abs(i)]);
-        }
-
-        [Test]
-        public void TestNegativeEnumArray()
-        {
-            int arraySize = 1 + 1 + (11 * 5);
-            int msgSize = arraySize;
-            byte[] bytes = new byte[msgSize];
-            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
-            output.WriteEnumArray(8, new RepeatedField<TestNegEnum> {
-                0, (TestNegEnum) (-1), TestNegEnum.Value, (TestNegEnum) (-3), (TestNegEnum) (-4), (TestNegEnum) (-5) });
-            Assert.AreEqual(0, output.SpaceLeft);
-
-            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
-            uint tag;
-            Assert.IsTrue(input.ReadTag(out tag));
-
-            List<int> values = new List<int>();
-            input.ReadInt32Array(values);
-
-            Assert.AreEqual(6, values.Count);
-            for (int i = 0; i > -6; i--)
-                Assert.AreEqual(i, values[Math.Abs(i)]);
-        }
-        */
-
         [Test]
         public void TestCodedInputOutputPosition()
         {
@@ -407,7 +336,7 @@ namespace Google.Protobuf
                 Assert.AreEqual(130, cout.Position);
                 cout.Flush();
             }
-            //Now test Input stream:
+            // Now test Input stream:
             {
                 CodedInputStream cin = CodedInputStream.CreateInstance(new MemoryStream(bytes), new byte[50]);
                 uint tag;
@@ -420,8 +349,8 @@ namespace Google.Protobuf
                 //Field 2:
                 Assert.IsTrue(cin.ReadTag(out tag) && tag >> 3 == 2);
                 Assert.AreEqual(4, cin.Position);
-                uint childlen = cin.ReadRawVarint32();
-                Assert.AreEqual(120u, childlen);
+                int childlen = cin.ReadLength();
+                Assert.AreEqual(120, childlen);
                 Assert.AreEqual(5, cin.Position);
                 int oldlimit = cin.PushLimit((int)childlen);
                 Assert.AreEqual(5, cin.Position);

csharp/src/ProtocolBuffers.Test/Collections/RepeatedFieldTest.cs

@@ -1,5 +1,39 @@
-using System;
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+#endregion
+
+using System;
 using System.Collections.Generic;
+using System.IO;
+using System.Linq;
 using Google.Protobuf.TestProtos;
 using NUnit.Framework;
 
@@ -89,5 +123,260 @@ namespace Google.Protobuf.Collections
             var clone = list.Clone();
             clone[0] = 1;
         }
+
+        [Test]
+        public void AddEntriesFrom_PackedInt32()
+        {
+            uint packedTag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            var length = CodedOutputStream.ComputeInt32Size(10)
+                + CodedOutputStream.ComputeInt32Size(999)
+                + CodedOutputStream.ComputeInt32Size(-1000);
+            output.WriteTag(packedTag);
+            output.WriteRawVarint32((uint) length);
+            output.WriteInt32(10);
+            output.WriteInt32(999);
+            output.WriteInt32(-1000);
+            output.Flush();
+            stream.Position = 0;
+
+            // Deliberately "expecting" a non-packed tag, but we detect that the data is
+            // actually packed.
+            uint nonPackedTag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var field = new RepeatedField<int>();
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(packedTag);
+            field.AddEntriesFrom(input, FieldCodec.ForInt32(nonPackedTag));
+            CollectionAssert.AreEqual(new[] { 10, 999, -1000 }, field);
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void AddEntriesFrom_NonPackedInt32()
+        {
+            uint nonPackedTag = WireFormat.MakeTag(10, WireFormat.WireType.Varint);
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            output.WriteTag(nonPackedTag);
+            output.WriteInt32(10);
+            output.WriteTag(nonPackedTag);
+            output.WriteInt32(999);
+            output.WriteTag(nonPackedTag);
+            output.WriteInt32(-1000); // Just for variety...
+            output.Flush();
+            stream.Position = 0;
+
+            // Deliberately "expecting" a packed tag, but we detect that the data is
+            // actually not packed.
+            uint packedTag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var field = new RepeatedField<int>();
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(nonPackedTag);
+            field.AddEntriesFrom(input, FieldCodec.ForInt32(packedTag));
+            CollectionAssert.AreEqual(new[] { 10, 999, -1000 }, field);
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void AddEntriesFrom_String()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            output.WriteTag(tag);
+            output.WriteString("Foo");
+            output.WriteTag(tag);
+            output.WriteString("");
+            output.WriteTag(tag);
+            output.WriteString("Bar");
+            output.Flush();
+            stream.Position = 0;
+
+            var field = new RepeatedField<string>();
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            field.AddEntriesFrom(input, FieldCodec.ForString(tag));
+            CollectionAssert.AreEqual(new[] { "Foo", "", "Bar" }, field);
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void AddEntriesFrom_Message()
+        {
+            var message1 = new ForeignMessage { C = 2000 };
+            var message2 = new ForeignMessage { C = -250 };
+
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            output.WriteTag(tag);
+            output.WriteMessage(message1);
+            output.WriteTag(tag);
+            output.WriteMessage(message2);
+            output.Flush();
+            stream.Position = 0;
+
+            var field = new RepeatedField<ForeignMessage>();
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            field.AddEntriesFrom(input, FieldCodec.ForMessage(tag, ForeignMessage.Parser));
+            CollectionAssert.AreEqual(new[] { message1, message2}, field);
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void WriteTo_PackedInt32()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var field = new RepeatedField<int> { 10, 1000, 1000000 };
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            field.WriteTo(output, FieldCodec.ForInt32(tag));
+            output.Flush();
+            stream.Position = 0;
+
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            var length = input.ReadLength();
+            Assert.AreEqual(10, input.ReadInt32());
+            Assert.AreEqual(1000, input.ReadInt32());
+            Assert.AreEqual(1000000, input.ReadInt32());
+            Assert.IsTrue(input.IsAtEnd);
+            Assert.AreEqual(1 + CodedOutputStream.ComputeLengthSize(length) + length, stream.Length);
+        }
+
+        [Test]
+        public void WriteTo_NonPackedInt32()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.Varint);
+            var field = new RepeatedField<int> { 10, 1000, 1000000};
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            field.WriteTo(output, FieldCodec.ForInt32(tag));
+            output.Flush();
+            stream.Position = 0;
+
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            Assert.AreEqual(10, input.ReadInt32());
+            input.AssertNextTag(tag);
+            Assert.AreEqual(1000, input.ReadInt32());
+            input.AssertNextTag(tag);
+            Assert.AreEqual(1000000, input.ReadInt32());
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void WriteTo_String()
+        {
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var field = new RepeatedField<string> { "Foo", "", "Bar" };
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            field.WriteTo(output, FieldCodec.ForString(tag));
+            output.Flush();
+            stream.Position = 0;
+
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            Assert.AreEqual("Foo", input.ReadString());
+            input.AssertNextTag(tag);
+            Assert.AreEqual("", input.ReadString());
+            input.AssertNextTag(tag);
+            Assert.AreEqual("Bar", input.ReadString());
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+        [Test]
+        public void WriteTo_Message()
+        {
+            var message1 = new ForeignMessage { C = 20 };
+            var message2 = new ForeignMessage { C = 25 };
+            uint tag = WireFormat.MakeTag(10, WireFormat.WireType.LengthDelimited);
+            var field = new RepeatedField<ForeignMessage> { message1, message2 };
+            var stream = new MemoryStream();
+            var output = CodedOutputStream.CreateInstance(stream);
+            field.WriteTo(output, FieldCodec.ForMessage(tag, ForeignMessage.Parser));
+            output.Flush();
+            stream.Position = 0;
+
+            var input = CodedInputStream.CreateInstance(stream);
+            input.AssertNextTag(tag);
+            Assert.AreEqual(message1, input.ReadMessage(ForeignMessage.Parser));
+            input.AssertNextTag(tag);
+            Assert.AreEqual(message2, input.ReadMessage(ForeignMessage.Parser));
+            Assert.IsTrue(input.IsAtEnd);
+        }
+
+
+        [Test]
+        public void TestNegativeEnumArray()
+        {
+            int arraySize = 1 + 1 + (11 * 5);
+            int msgSize = arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            uint tag = WireFormat.MakeTag(8, WireFormat.WireType.Varint);
+            for (int i = 0; i >= -5; i--)
+            {
+                output.WriteTag(tag);
+                output.WriteEnum(i);
+            }
+
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            Assert.IsTrue(input.ReadTag(out tag));
+
+            RepeatedField<SampleEnum> values = new RepeatedField<SampleEnum>();
+            values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (SampleEnum)x));
+
+            Assert.AreEqual(6, values.Count);
+            Assert.AreEqual(SampleEnum.None, values[0]);
+            Assert.AreEqual(((SampleEnum)(-1)), values[1]);
+            Assert.AreEqual(SampleEnum.NegativeValue, values[2]);
+            Assert.AreEqual(((SampleEnum)(-3)), values[3]);
+            Assert.AreEqual(((SampleEnum)(-4)), values[4]);
+            Assert.AreEqual(((SampleEnum)(-5)), values[5]);
+        }
+
+
+        [Test]
+        public void TestNegativeEnumPackedArray()
+        {
+            int arraySize = 1 + (10 * 5);
+            int msgSize = 1 + 1 + arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            // Length-delimited to show we want the packed representation
+            uint tag = WireFormat.MakeTag(8, WireFormat.WireType.LengthDelimited);
+            output.WriteTag(tag);
+            int size = 0;
+            for (int i = 0; i >= -5; i--)
+            {
+                size += CodedOutputStream.ComputeEnumSize(i);
+            }
+            output.WriteRawVarint32((uint)size);
+            for (int i = 0; i >= -5; i--)
+            {
+                output.WriteEnum(i);
+            }
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            Assert.IsTrue(input.ReadTag(out tag));
+
+            RepeatedField<SampleEnum> values = new RepeatedField<SampleEnum>();
+            values.AddEntriesFrom(input, FieldCodec.ForEnum(tag, x => (int)x, x => (SampleEnum)x));
+
+            Assert.AreEqual(6, values.Count);
+            Assert.AreEqual(SampleEnum.None, values[0]);
+            Assert.AreEqual(((SampleEnum)(-1)), values[1]);
+            Assert.AreEqual(SampleEnum.NegativeValue, values[2]);
+            Assert.AreEqual(((SampleEnum)(-3)), values[3]);
+            Assert.AreEqual(((SampleEnum)(-4)), values[4]);
+            Assert.AreEqual(((SampleEnum)(-5)), values[5]);
+        }
     }
 }

csharp/src/ProtocolBuffers.Test/FieldCodecTest.cs

@@ -63,15 +63,21 @@ namespace Google.Protobuf
         };
 
         [Test, TestCaseSource("Codecs")]
-        public void RoundTrip(ICodecTestData codec)
+        public void RoundTripWithTag(ICodecTestData codec)
         {
-            codec.TestRoundTrip();
+            codec.TestRoundTripWithTag();
+        }
+
+        [Test, TestCaseSource("Codecs")]
+        public void RoundTripRaw(ICodecTestData codec)
+        {
+            codec.TestRoundTripRaw();
         }
 
         [Test, TestCaseSource("Codecs")]
         public void CalculateSize(ICodecTestData codec)
         {
-            codec.TestCalculateSize();
+            codec.TestCalculateSizeWithTag();
         }
 
         [Test, TestCaseSource("Codecs")]
@@ -82,8 +88,9 @@ namespace Google.Protobuf
 
         public interface ICodecTestData
         {
-            void TestRoundTrip();
-            void TestCalculateSize();
+            void TestRoundTripRaw();
+            void TestRoundTripWithTag();
+            void TestCalculateSizeWithTag();
             void TestDefaultValue();
         }
 
@@ -100,7 +107,19 @@ namespace Google.Protobuf
                 this.name = name;
             }
 
-            public void TestRoundTrip()
+            public void TestRoundTripRaw()
+            {
+                var stream = new MemoryStream();
+                var codedOutput = CodedOutputStream.CreateInstance(stream);
+                codec.ValueWriter(codedOutput, sampleValue);
+                codedOutput.Flush();
+                stream.Position = 0;
+                var codedInput = CodedInputStream.CreateInstance(stream);
+                Assert.AreEqual(sampleValue, codec.ValueReader(codedInput));
+                Assert.IsTrue(codedInput.IsAtEnd);
+            }
+
+            public void TestRoundTripWithTag()
             {
                 var stream = new MemoryStream();
                 var codedOutput = CodedOutputStream.CreateInstance(stream);
@@ -108,14 +127,12 @@ namespace Google.Protobuf
                 codedOutput.Flush();
                 stream.Position = 0;
                 var codedInput = CodedInputStream.CreateInstance(stream);
-                uint tag;
-                Assert.IsTrue(codedInput.ReadTag(out tag));
-                Assert.AreEqual(codec.Tag, tag);
+                codedInput.AssertNextTag(codec.Tag);
                 Assert.AreEqual(sampleValue, codec.Read(codedInput));
                 Assert.IsTrue(codedInput.IsAtEnd);
             }
 
-            public void TestCalculateSize()
+            public void TestCalculateSizeWithTag()
             {
                 var stream = new MemoryStream();
                 var codedOutput = CodedOutputStream.CreateInstance(stream);
@@ -126,6 +143,7 @@ namespace Google.Protobuf
 
             public void TestDefaultValue()
             {
+                // WriteTagAndValue ignores default values
                 var stream = new MemoryStream();
                 var codedOutput = CodedOutputStream.CreateInstance(stream);
                 codec.WriteTagAndValue(codedOutput, codec.DefaultValue);
@@ -136,9 +154,20 @@ namespace Google.Protobuf
                 {
                     Assert.AreEqual(default(T), codec.DefaultValue);
                 }
-            }
 
-            public string Description { get { return name; } }
+                // The plain ValueWriter/ValueReader delegates don't.
+                if (codec.DefaultValue != null) // This part isn't appropriate for message types.
+                {
+                    codedOutput = CodedOutputStream.CreateInstance(stream);
+                    codec.ValueWriter(codedOutput, codec.DefaultValue);
+                    codedOutput.Flush();
+                    Assert.AreNotEqual(0, stream.Position);
+                    Assert.AreEqual(stream.Position, codec.ValueSizeCalculator(codec.DefaultValue));
+                    stream.Position = 0;
+                    var codedInput = CodedInputStream.CreateInstance(stream);
+                    Assert.AreEqual(codec.DefaultValue, codec.ValueReader(codedInput));
+                }
+            }
 
             public override string ToString()
             {

csharp/src/ProtocolBuffers.Test/GeneratedMessageTest.cs

@@ -10,6 +10,61 @@ namespace Google.Protobuf
     /// </summary>
     public class GeneratedMessageTest
     {
+        /// <summary>
+        /// Returns a sample TestAllTypes with all fields populated
+        /// </summary>
+        public static TestAllTypes GetSampleMessage()
+        {
+            return new TestAllTypes
+            {
+                SingleBool = true,
+                SingleBytes = ByteString.CopyFrom(1, 2, 3, 4),
+                SingleDouble = 23.5,
+                SingleFixed32 = 23,
+                SingleFixed64 = 1234567890123,
+                SingleFloat = 12.25f,
+                SingleForeignEnum = ForeignEnum.FOREIGN_BAR,
+                SingleForeignMessage = new ForeignMessage { C = 10 },
+                SingleImportEnum = ImportEnum.IMPORT_BAZ,
+                SingleImportMessage = new ImportMessage { D = 20 },
+                SingleInt32 = 100,
+                SingleInt64 = 3210987654321,
+                SingleNestedEnum = TestAllTypes.Types.NestedEnum.FOO,
+                SingleNestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 35 },
+                SinglePublicImportMessage = new PublicImportMessage { E = 54 },
+                SingleSfixed32 = -123,
+                SingleSfixed64 = -12345678901234,
+                SingleSint32 = -456,
+                SingleSint64 = -12345678901235,
+                SingleString = "test",
+                SingleUint32 = uint.MaxValue,
+                SingleUint64 = ulong.MaxValue,
+                RepeatedBool = { true, false },
+                RepeatedBytes = { ByteString.CopyFrom(1, 2, 3, 4), ByteString.CopyFrom(5, 6), ByteString.CopyFrom(new byte[1000]) },
+                RepeatedDouble = { -12.25, 23.5 },
+                RepeatedFixed32 = { uint.MaxValue, 23 },
+                RepeatedFixed64 = { ulong.MaxValue, 1234567890123 },
+                RepeatedFloat = { 100f, 12.25f },
+                RepeatedForeignEnum = { ForeignEnum.FOREIGN_FOO, ForeignEnum.FOREIGN_BAR },
+                RepeatedForeignMessage = { new ForeignMessage(), new ForeignMessage { C = 10 } },
+                RepeatedImportEnum = { ImportEnum.IMPORT_BAZ, ImportEnum.IMPORT_ENUM_UNSPECIFIED },
+                RepeatedImportMessage = { new ImportMessage { D = 20 }, new ImportMessage { D = 25 } },
+                RepeatedInt32 = { 100, 200 },
+                RepeatedInt64 = { 3210987654321, long.MaxValue },
+                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.FOO, TestAllTypes.Types.NestedEnum.NEG },
+                RepeatedNestedMessage = { new TestAllTypes.Types.NestedMessage { Bb = 35 }, new TestAllTypes.Types.NestedMessage { Bb = 10 } },
+                RepeatedPublicImportMessage = { new PublicImportMessage { E = 54 }, new PublicImportMessage { E = -1 } },
+                RepeatedSfixed32 = { -123, 123 },
+                RepeatedSfixed64 = { -12345678901234, 12345678901234 },
+                RepeatedSint32 = { -456, 100 },
+                RepeatedSint64 = { -12345678901235, 123 },
+                RepeatedString = { "foo", "bar" },
+                RepeatedUint32 = { uint.MaxValue, uint.MinValue },
+                RepeatedUint64 = { ulong.MaxValue, uint.MinValue },
+                OneofString = "Oneof string"                
+            };
+        }
+
         [Test]
         public void EmptyMessageFieldDistinctFromMissingMessageField()
         {
@@ -485,5 +540,83 @@ namespace Google.Protobuf
             Assert.Throws<InvalidOperationException>(() => frozen.RepeatedDouble.Add(0.0));
             Assert.Throws<InvalidOperationException>(() => frozen.RepeatedNestedMessage.Add(new TestAllTypes.Types.NestedMessage()));
         }
+
+        [Test]
+        public void OneofProperties()
+        {
+            // Switch the oneof case between each of the different options, and check everything behaves
+            // as expected in each case.
+            var message = new TestAllTypes();
+            Assert.AreEqual("", message.OneofString);
+            Assert.AreEqual(0, message.OneofUint32);
+            Assert.AreEqual(ByteString.Empty, message.OneofBytes);
+            Assert.IsNull(message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.None, message.OneofFieldCase);
+
+            message.OneofString = "sample";
+            Assert.AreEqual("sample", message.OneofString);
+            Assert.AreEqual(0, message.OneofUint32);
+            Assert.AreEqual(ByteString.Empty, message.OneofBytes);
+            Assert.IsNull(message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofString, message.OneofFieldCase);
+
+            var bytes = ByteString.CopyFrom(1, 2, 3);
+            message.OneofBytes = bytes;
+            Assert.AreEqual("", message.OneofString);
+            Assert.AreEqual(0, message.OneofUint32);
+            Assert.AreEqual(bytes, message.OneofBytes);
+            Assert.IsNull(message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofBytes, message.OneofFieldCase);
+
+            message.OneofUint32 = 20;
+            Assert.AreEqual("", message.OneofString);
+            Assert.AreEqual(20, message.OneofUint32);
+            Assert.AreEqual(ByteString.Empty, message.OneofBytes);
+            Assert.IsNull(message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofUint32, message.OneofFieldCase);
+
+            var nestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 25 };
+            message.OneofNestedMessage = nestedMessage;
+            Assert.AreEqual("", message.OneofString);
+            Assert.AreEqual(0, message.OneofUint32);
+            Assert.AreEqual(ByteString.Empty, message.OneofBytes);
+            Assert.AreEqual(nestedMessage, message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofNestedMessage, message.OneofFieldCase);
+
+            message.ClearOneofField();
+            Assert.AreEqual("", message.OneofString);
+            Assert.AreEqual(0, message.OneofUint32);
+            Assert.AreEqual(ByteString.Empty, message.OneofBytes);
+            Assert.IsNull(message.OneofNestedMessage);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.None, message.OneofFieldCase);
+        }
+
+        [Test]
+        public void OneofSerialization_NonDefaultValue()
+        {
+            var message = new TestAllTypes();
+            message.OneofString = "this would take a bit of space";
+            message.OneofUint32 = 10;
+            var bytes = message.ToByteArray();
+            Assert.AreEqual(3, bytes.Length); // 2 bytes for the tag + 1 for the value - no string!
+
+            var message2 = TestAllTypes.Parser.ParseFrom(bytes);
+            Assert.AreEqual(message, message2);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofUint32, message2.OneofFieldCase);
+        }
+
+        [Test]
+        public void OneofSerialization_DefaultValue()
+        {
+            var message = new TestAllTypes();
+            message.OneofString = "this would take a bit of space";
+            message.OneofUint32 = 0; // This is the default value for UInt32; normally wouldn't be serialized
+            var bytes = message.ToByteArray();
+            Assert.AreEqual(3, bytes.Length); // 2 bytes for the tag + 1 for the value - it's still serialized
+
+            var message2 = TestAllTypes.Parser.ParseFrom(bytes);
+            Assert.AreEqual(message, message2);
+            Assert.AreEqual(TestAllTypes.OneofFieldOneofCase.OneofUint32, message2.OneofFieldCase);
+        }
     }
 }

csharp/src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj

@@ -72,6 +72,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="ByteStringTest.cs" />
+    <Compile Include="CodedInputStreamExtensions.cs" />
     <Compile Include="CodedInputStreamTest.cs" />
     <Compile Include="CodedOutputStreamTest.cs" />
     <Compile Include="EqualityTester.cs" />
@@ -79,6 +80,7 @@
     <Compile Include="GeneratedMessageTest.cs" />
     <Compile Include="Collections\MapFieldTest.cs" />
     <Compile Include="Collections\RepeatedFieldTest.cs" />
+    <Compile Include="SampleEnum.cs" />
     <Compile Include="TestProtos\MapUnittestProto3.cs" />
     <Compile Include="TestProtos\UnittestImportProto3.cs" />
     <Compile Include="TestProtos\UnittestImportPublicProto3.cs" />

csharp/src/ProtocolBuffers.Test/SampleEnum.cs

@@ -0,0 +1,42 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+#endregion
+    
+namespace Google.Protobuf
+{
+    // Just a sample enum with positive and negative values to be used in tests.
+    internal enum SampleEnum
+    {
+        NegativeValue = -2,
+        None = 0,
+        PositiveValue = 3
+    }
+}

csharp/src/ProtocolBuffers/CodedInputStream.cs

@@ -37,7 +37,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using Google.Protobuf.Collections;
 
 namespace Google.Protobuf
 {
@@ -178,8 +177,61 @@ namespace Google.Protobuf
         /// </summary>
         internal uint LastTag { get { return lastTag; } }
 
-        #region Validation
+        #region Limits for recursion and length
+        /// <summary>
+        /// Set the maximum message recursion depth.
+        /// </summary>
+        /// <remarks>
+        /// In order to prevent malicious
+        /// messages from causing stack overflows, CodedInputStream limits
+        /// how deeply messages may be nested.  The default limit is 64.
+        /// </remarks>
+        public int SetRecursionLimit(int limit)
+        {
+            if (limit < 0)
+            {
+                throw new ArgumentOutOfRangeException("Recursion limit cannot be negative: " + limit);
+            }
+            int oldLimit = recursionLimit;
+            recursionLimit = limit;
+            return oldLimit;
+        }
+
+        /// <summary>
+        /// Set the maximum message size.
+        /// </summary>
+        /// <remarks>
+        /// In order to prevent malicious messages from exhausting memory or
+        /// causing integer overflows, CodedInputStream limits how large a message may be.
+        /// The default limit is 64MB.  You should set this limit as small
+        /// as you can without harming your app's functionality.  Note that
+        /// size limits only apply when reading from an InputStream, not
+        /// when constructed around a raw byte array (nor with ByteString.NewCodedInput).
+        /// If you want to read several messages from a single CodedInputStream, you
+        /// can call ResetSizeCounter() after each message to avoid hitting the
+        /// size limit.
+        /// </remarks>
+        public int SetSizeLimit(int limit)
+        {
+            if (limit < 0)
+            {
+                throw new ArgumentOutOfRangeException("Size limit cannot be negative: " + limit);
+            }
+            int oldLimit = sizeLimit;
+            sizeLimit = limit;
+            return oldLimit;
+        }
+
+        /// <summary>
+        /// Resets the current size counter to zero (see <see cref="SetSizeLimit"/>).
+        /// </summary>
+        public void ResetSizeCounter()
+        {
+            totalBytesRetired = 0;
+        }
+        #endregion
 
+        #region Validation
         /// <summary>
         /// Verifies that the last call to ReadTag() returned the given tag value.
         /// This is used to verify that a nested group ended with the correct
@@ -194,13 +246,12 @@ namespace Google.Protobuf
                 throw InvalidProtocolBufferException.InvalidEndTag();
             }
         }
-
         #endregion
 
         #region Reading of tags etc
 
         /// <summary>
-        /// Attempt to peek at the next field tag.
+        /// Attempts to peek at the next field tag.
         /// </summary>
         public bool PeekNextTag(out uint fieldTag)
         {
@@ -218,7 +269,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Attempt to read a field tag, returning false if we have reached the end
+        /// Attempts to read a field tag, returning false if we have reached the end
         /// of the input data.
         /// </summary>
         /// <param name="fieldTag">The 'tag' of the field (id * 8 + wire-format)</param>
@@ -233,14 +284,42 @@ namespace Google.Protobuf
                 return true;
             }
 
-            if (IsAtEnd)
+            // Optimize for the incredibly common case of having at least two bytes left in the buffer,
+            // and those two bytes being enough to get the tag. This will be true for fields up to 4095.
+            if (bufferPos + 2 <= bufferSize)
             {
-                fieldTag = 0;
-                lastTag = fieldTag;
-                return false;
+                int tmp = buffer[bufferPos++];
+                if (tmp < 128)
+                {
+                    fieldTag = (uint)tmp;
+                }
+                else
+                {
+                    int result = tmp & 0x7f;
+                    if ((tmp = buffer[bufferPos++]) < 128)
+                    {
+                        result |= tmp << 7;
+                        fieldTag = (uint) result;
+                    }
+                    else
+                    {
+                        // Nope, rewind and go the potentially slow route.
+                        bufferPos -= 2;
+                        fieldTag = ReadRawVarint32();
+                    }
+                }
             }
+            else
+            {
+                if (IsAtEnd)
+                {
+                    fieldTag = 0;
+                    lastTag = fieldTag;
+                    return false;
+                }
 
-            fieldTag = ReadRawVarint32();
+                fieldTag = ReadRawVarint32();
+            }
             lastTag = fieldTag;
             if (lastTag == 0)
             {
@@ -251,7 +330,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a double field from the stream.
+        /// Reads a double field from the stream.
         /// </summary>
         public double ReadDouble()
         {
@@ -259,7 +338,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a float field from the stream.
+        /// Reads a float field from the stream.
         /// </summary>
         public float ReadFloat()
         {
@@ -281,7 +360,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a uint64 field from the stream.
+        /// Reads a uint64 field from the stream.
         /// </summary>
         public ulong ReadUInt64()
         {
@@ -289,7 +368,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read an int64 field from the stream.
+        /// Reads an int64 field from the stream.
         /// </summary>
         public long ReadInt64()
         {
@@ -297,7 +376,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read an int32 field from the stream.
+        /// Reads an int32 field from the stream.
         /// </summary>
         public int ReadInt32()
         {
@@ -305,7 +384,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a fixed64 field from the stream.
+        /// Reads a fixed64 field from the stream.
         /// </summary>
         public ulong ReadFixed64()
         {
@@ -313,7 +392,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a fixed32 field from the stream.
+        /// Reads a fixed32 field from the stream.
         /// </summary>
         public uint ReadFixed32()
         {
@@ -321,7 +400,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a bool field from the stream.
+        /// Reads a bool field from the stream.
         /// </summary>
         public bool ReadBool()
         {
@@ -333,22 +412,22 @@ namespace Google.Protobuf
         /// </summary>
         public string ReadString()
         {
-            int size = (int) ReadRawVarint32();
+            int length = ReadLength();
             // No need to read any data for an empty string.
-            if (size == 0)
+            if (length == 0)
             {
                 return "";
             }
-            if (size <= bufferSize - bufferPos)
+            if (length <= bufferSize - bufferPos)
             {
                 // Fast path:  We already have the bytes in a contiguous buffer, so
                 //   just copy directly from it.
-                String result = CodedOutputStream.Utf8Encoding.GetString(buffer, bufferPos, size);
-                bufferPos += size;
+                String result = CodedOutputStream.Utf8Encoding.GetString(buffer, bufferPos, length);
+                bufferPos += length;
                 return result;
             }
             // Slow path: Build a byte array first then copy it.
-            return CodedOutputStream.Utf8Encoding.GetString(ReadRawBytes(size), 0, size);
+            return CodedOutputStream.Utf8Encoding.GetString(ReadRawBytes(length), 0, length);
         }
 
         /// <summary>
@@ -356,7 +435,7 @@ namespace Google.Protobuf
         /// </summary>   
         public void ReadMessage(IMessage builder)
         {
-            int length = (int) ReadRawVarint32();
+            int length = ReadLength();
             if (recursionDepth >= recursionLimit)
             {
                 throw InvalidProtocolBufferException.RecursionLimitExceeded();
@@ -374,19 +453,19 @@ namespace Google.Protobuf
         /// </summary>   
         public ByteString ReadBytes()
         {
-            int size = (int) ReadRawVarint32();
-            if (size <= bufferSize - bufferPos && size > 0)
+            int length = ReadLength();
+            if (length <= bufferSize - bufferPos && length > 0)
             {
                 // Fast path:  We already have the bytes in a contiguous buffer, so
                 //   just copy directly from it.
-                ByteString result = ByteString.CopyFrom(buffer, bufferPos, size);
-                bufferPos += size;
+                ByteString result = ByteString.CopyFrom(buffer, bufferPos, length);
+                bufferPos += length;
                 return result;
             }
             else
             {
                 // Slow path:  Build a byte array and attach it to a new ByteString.
-                return ByteString.AttachBytes(ReadRawBytes(size));
+                return ByteString.AttachBytes(ReadRawBytes(length));
             }
         }
 
@@ -441,6 +520,18 @@ namespace Google.Protobuf
             return DecodeZigZag64(ReadRawVarint64());
         }
 
+        /// <summary>
+        /// Reads a length for length-delimited data.
+        /// </summary>
+        /// <remarks>
+        /// This is internally just reading a varint, but this method exists
+        /// to make the calling code clearer.
+        /// </remarks>
+        public int ReadLength()
+        {
+            return (int) ReadRawVarint32();
+        }
+
         /// <summary>
         /// Peeks at the next tag in the stream. If it matches <paramref name="tag"/>,
         /// the tag is consumed and the method returns <c>true</c>; otherwise, the
@@ -517,12 +608,12 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a raw Varint from the stream.  If larger than 32 bits, discard the upper bits.
+        /// Reads a raw Varint from the stream.  If larger than 32 bits, discard the upper bits.
         /// This method is optimised for the case where we've got lots of data in the buffer.
         /// That means we can check the size just once, then just read directly from the buffer
         /// without constant rechecking of the buffer length.
         /// </summary>
-        public uint ReadRawVarint32()
+        internal uint ReadRawVarint32()
         {
             if (bufferPos + 5 > bufferSize)
             {
@@ -581,13 +672,13 @@ namespace Google.Protobuf
         /// <summary>
         /// Reads a varint from the input one byte at a time, so that it does not
         /// read any bytes after the end of the varint. If you simply wrapped the
-        /// stream in a CodedInputStream and used ReadRawVarint32(Stream)}
+        /// stream in a CodedInputStream and used ReadRawVarint32(Stream)
         /// then you would probably end up reading past the end of the varint since
         /// CodedInputStream buffers its input.
         /// </summary>
         /// <param name="input"></param>
         /// <returns></returns>
-        public static uint ReadRawVarint32(Stream input)
+        internal static uint ReadRawVarint32(Stream input)
         {
             int result = 0;
             int offset = 0;
@@ -621,9 +712,9 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a raw varint from the stream.
+        /// Reads a raw varint from the stream.
         /// </summary>
-        public ulong ReadRawVarint64()
+        internal ulong ReadRawVarint64()
         {
             int shift = 0;
             ulong result = 0;
@@ -641,9 +732,9 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a 32-bit little-endian integer from the stream.
+        /// Reads a 32-bit little-endian integer from the stream.
         /// </summary>
-        public uint ReadRawLittleEndian32()
+        internal uint ReadRawLittleEndian32()
         {
             uint b1 = ReadRawByte();
             uint b2 = ReadRawByte();
@@ -653,9 +744,9 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a 64-bit little-endian integer from the stream.
+        /// Reads a 64-bit little-endian integer from the stream.
         /// </summary>
-        public ulong ReadRawLittleEndian64()
+        internal ulong ReadRawLittleEndian64()
         {
             ulong b1 = ReadRawByte();
             ulong b2 = ReadRawByte();
@@ -669,8 +760,6 @@ namespace Google.Protobuf
                    | (b5 << 32) | (b6 << 40) | (b7 << 48) | (b8 << 56);
         }
 
-        #endregion
-
         /// <summary>
         /// Decode a 32-bit value with ZigZag encoding.
         /// </summary>
@@ -680,9 +769,9 @@ namespace Google.Protobuf
         /// sign-extended to 64 bits to be varint encoded, thus always taking
         /// 10 bytes on the wire.)
         /// </remarks>
-        public static int DecodeZigZag32(uint n)
+        internal static int DecodeZigZag32(uint n)
         {
-            return (int) (n >> 1) ^ -(int) (n & 1);
+            return (int)(n >> 1) ^ -(int)(n & 1);
         }
 
         /// <summary>
@@ -694,72 +783,21 @@ namespace Google.Protobuf
         /// sign-extended to 64 bits to be varint encoded, thus always taking
         /// 10 bytes on the wire.)
         /// </remarks>
-        public static long DecodeZigZag64(ulong n)
-        {
-            return (long) (n >> 1) ^ -(long) (n & 1);
-        }
-
-        /// <summary>
-        /// Set the maximum message recursion depth.
-        /// </summary>
-        /// <remarks>
-        /// In order to prevent malicious
-        /// messages from causing stack overflows, CodedInputStream limits
-        /// how deeply messages may be nested.  The default limit is 64.
-        /// </remarks>
-        public int SetRecursionLimit(int limit)
-        {
-            if (limit < 0)
-            {
-                throw new ArgumentOutOfRangeException("Recursion limit cannot be negative: " + limit);
-            }
-            int oldLimit = recursionLimit;
-            recursionLimit = limit;
-            return oldLimit;
-        }
-
-        /// <summary>
-        /// Set the maximum message size.
-        /// </summary>
-        /// <remarks>
-        /// In order to prevent malicious messages from exhausting memory or
-        /// causing integer overflows, CodedInputStream limits how large a message may be.
-        /// The default limit is 64MB.  You should set this limit as small
-        /// as you can without harming your app's functionality.  Note that
-        /// size limits only apply when reading from an InputStream, not
-        /// when constructed around a raw byte array (nor with ByteString.NewCodedInput).
-        /// If you want to read several messages from a single CodedInputStream, you
-        /// can call ResetSizeCounter() after each message to avoid hitting the
-        /// size limit.
-        /// </remarks>
-        public int SetSizeLimit(int limit)
+        internal static long DecodeZigZag64(ulong n)
         {
-            if (limit < 0)
-            {
-                throw new ArgumentOutOfRangeException("Size limit cannot be negative: " + limit);
-            }
-            int oldLimit = sizeLimit;
-            sizeLimit = limit;
-            return oldLimit;
+            return (long)(n >> 1) ^ -(long)(n & 1);
         }
+        #endregion
 
         #region Internal reading and buffer management
 
-        /// <summary>
-        /// Resets the current size counter to zero (see SetSizeLimit).
-        /// </summary>
-        public void ResetSizeCounter()
-        {
-            totalBytesRetired = 0;
-        }
-
         /// <summary>
         /// Sets currentLimit to (current position) + byteLimit. This is called
         /// when descending into a length-delimited embedded message. The previous
         /// limit is returned.
         /// </summary>
         /// <returns>The old limit.</returns>
-        public int PushLimit(int byteLimit)
+        internal int PushLimit(int byteLimit)
         {
             if (byteLimit < 0)
             {
@@ -797,7 +835,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Discards the current limit, returning the previous limit.
         /// </summary>
-        public void PopLimit(int oldLimit)
+        internal void PopLimit(int oldLimit)
         {
             currentLimit = oldLimit;
             RecomputeBufferSizeAfterLimit();
@@ -807,7 +845,7 @@ namespace Google.Protobuf
         /// Returns whether or not all the data before the limit has been read.
         /// </summary>
         /// <returns></returns>
-        public bool ReachedLimit
+        internal bool ReachedLimit
         {
             get
             {
@@ -897,7 +935,7 @@ namespace Google.Protobuf
         /// <exception cref="InvalidProtocolBufferException">
         /// the end of the stream or the current limit was reached
         /// </exception>
-        public byte ReadRawByte()
+        internal byte ReadRawByte()
         {
             if (bufferPos == bufferSize)
             {
@@ -907,12 +945,12 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Read a fixed size of bytes from the input.
+        /// Reads a fixed size of bytes from the input.
         /// </summary>
         /// <exception cref="InvalidProtocolBufferException">
         /// the end of the stream or the current limit was reached
         /// </exception>
-        public byte[] ReadRawBytes(int size)
+        internal byte[] ReadRawBytes(int size)
         {
             if (size < 0)
             {
@@ -921,7 +959,8 @@ namespace Google.Protobuf
 
             if (totalBytesRetired + bufferPos + size > currentLimit)
             {
-                // Read to the end of the stream anyway.
+                // Read to the end of the stream (up to the current limit) anyway.
+                // TODO(jonskeet): This is the only usage of SkipRawBytes. Do we really need to do it?
                 SkipRawBytes(currentLimit - totalBytesRetired - bufferPos);
                 // Then fail.
                 throw InvalidProtocolBufferException.TruncatedMessage();
@@ -1025,63 +1064,12 @@ namespace Google.Protobuf
             }
         }
 
-        /// <summary>
-        /// Reads and discards a single field, given its tag value.
-        /// </summary>
-        /// <returns>false if the tag is an end-group tag, in which case
-        /// nothing is skipped. Otherwise, returns true.</returns>
-        public bool SkipField()
-        {
-            uint tag = lastTag;
-            switch (WireFormat.GetTagWireType(tag))
-            {
-                case WireFormat.WireType.Varint:
-                    ReadRawVarint64();
-                    return true;
-                case WireFormat.WireType.Fixed64:
-                    ReadRawLittleEndian64();
-                    return true;
-                case WireFormat.WireType.LengthDelimited:
-                    SkipRawBytes((int) ReadRawVarint32());
-                    return true;
-                case WireFormat.WireType.StartGroup:
-                    SkipMessage();
-                    CheckLastTagWas(
-                        WireFormat.MakeTag(WireFormat.GetTagFieldNumber(tag),
-                                           WireFormat.WireType.EndGroup));
-                    return true;
-                case WireFormat.WireType.EndGroup:
-                    return false;
-                case WireFormat.WireType.Fixed32:
-                    ReadRawLittleEndian32();
-                    return true;
-                default:
-                    throw InvalidProtocolBufferException.InvalidWireType();
-            }
-        }
-
-        /// <summary>
-        /// Reads and discards an entire message.  This will read either until EOF
-        /// or until an endgroup tag, whichever comes first.
-        /// </summary>
-        public void SkipMessage()
-        {
-            uint tag;
-            while (ReadTag(out tag))
-            {
-                if (!SkipField())
-                {
-                    return;
-                }
-            }
-        }
-
         /// <summary>
         /// Reads and discards <paramref name="size"/> bytes.
         /// </summary>
         /// <exception cref="InvalidProtocolBufferException">the end of the stream
         /// or the current limit was reached</exception>
-        public void SkipRawBytes(int size)
+        private void SkipRawBytes(int size)
         {
             if (size < 0)
             {

csharp/src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs

@@ -50,7 +50,7 @@ namespace Google.Protobuf
         private const int LittleEndian32Size = 4;        
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// double field, including the tag.
         /// </summary>
         public static int ComputeDoubleSize(double value)
@@ -59,7 +59,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// float field, including the tag.
         /// </summary>
         public static int ComputeFloatSize(float value)
@@ -68,7 +68,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// uint64 field, including the tag.
         /// </summary>
         public static int ComputeUInt64Size(ulong value)
@@ -77,7 +77,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// int64 field, including the tag.
         /// </summary>
         public static int ComputeInt64Size(long value)
@@ -86,7 +86,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// int32 field, including the tag.
         /// </summary>
         public static int ComputeInt32Size(int value)
@@ -103,7 +103,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// fixed64 field, including the tag.
         /// </summary>
         public static int ComputeFixed64Size(ulong value)
@@ -112,7 +112,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// fixed32 field, including the tag.
         /// </summary>
         public static int ComputeFixed32Size(uint value)
@@ -121,7 +121,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// bool field, including the tag.
         /// </summary>
         public static int ComputeBoolSize(bool value)
@@ -130,7 +130,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// string field, including the tag.
         /// </summary>
         public static int ComputeStringSize(String value)
@@ -141,7 +141,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// group field, including the tag.
         /// </summary>
         public static int ComputeGroupSize(IMessage value)
@@ -150,7 +150,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// embedded message field, including the tag.
         /// </summary>
         public static int ComputeMessageSize(IMessage value)
@@ -160,7 +160,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// bytes field, including the tag.
         /// </summary>
         public static int ComputeBytesSize(ByteString value)
@@ -170,7 +170,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// uint32 field, including the tag.
         /// </summary>
         public static int ComputeUInt32Size(uint value)
@@ -179,7 +179,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a
+        /// Computes the number of bytes that would be needed to encode a
         /// enum field, including the tag. The caller is responsible for
         /// converting the enum value to its numeric value.
         /// </summary>
@@ -190,7 +190,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// sfixed32 field, including the tag.
         /// </summary>
         public static int ComputeSFixed32Size(int value)
@@ -199,7 +199,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// sfixed64 field, including the tag.
         /// </summary>
         public static int ComputeSFixed64Size(long value)
@@ -208,7 +208,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// sint32 field, including the tag.
         /// </summary>
         public static int ComputeSInt32Size(int value)
@@ -217,7 +217,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode an
+        /// Computes the number of bytes that would be needed to encode an
         /// sint64 field, including the tag.
         /// </summary>
         public static int ComputeSInt64Size(long value)
@@ -226,7 +226,16 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a varint.
+        /// Computes the number of bytes that would be needed to encode a length,
+        /// as written by <see cref="WriteLength"/>.
+        /// </summary>
+        public static int ComputeLengthSize(int length)
+        {
+            return ComputeRawVarint32Size((uint) length);
+        }
+
+        /// <summary>
+        /// Computes the number of bytes that would be needed to encode a varint.
         /// </summary>
         public static int ComputeRawVarint32Size(uint value)
         {
@@ -250,7 +259,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a varint.
+        /// Computes the number of bytes that would be needed to encode a varint.
         /// </summary>
         public static int ComputeRawVarint64Size(ulong value)
         {
@@ -294,7 +303,7 @@ namespace Google.Protobuf
         }
 
         /// <summary>
-        /// Compute the number of bytes that would be needed to encode a tag.
+        /// Computes the number of bytes that would be needed to encode a tag.
         /// </summary>
         public static int ComputeTagSize(int fieldNumber)
         {

csharp/src/ProtocolBuffers/CodedOutputStream.cs

@@ -37,7 +37,6 @@
 using System;
 using System.IO;
 using System.Text;
-using Google.Protobuf.Collections;
 
 namespace Google.Protobuf
 {
@@ -141,11 +140,12 @@ namespace Google.Protobuf
             }
         }
 
-        #region Writing of values without tags
+        #region Writing of values (not including tags)
 
         /// <summary>
-        /// Writes a double field value, including tag, to the stream.
+        /// Writes a double field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteDouble(double value)
         {
             WriteRawLittleEndian64((ulong)BitConverter.DoubleToInt64Bits(value));
@@ -154,6 +154,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes a float field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteFloat(float value)
         {
             byte[] rawBytes = BitConverter.GetBytes(value);
@@ -178,6 +179,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes a uint64 field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteUInt64(ulong value)
         {
             WriteRawVarint64(value);
@@ -186,6 +188,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes an int64 field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteInt64(long value)
         {
             WriteRawVarint64((ulong) value);
@@ -194,6 +197,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes an int32 field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteInt32(int value)
         {
             if (value >= 0)
@@ -210,6 +214,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes a fixed64 field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteFixed64(ulong value)
         {
             WriteRawLittleEndian64(value);
@@ -218,6 +223,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes a fixed32 field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteFixed32(uint value)
         {
             WriteRawLittleEndian32(value);
@@ -226,6 +232,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes a bool field value, without a tag, to the stream.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteBool(bool value)
         {
             WriteRawByte(value ? (byte) 1 : (byte) 0);
@@ -233,13 +240,15 @@ namespace Google.Protobuf
 
         /// <summary>
         /// Writes a string field value, without a tag, to the stream.
+        /// The data is length-prefixed.
         /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteString(string value)
         {
             // Optimise the case where we have enough space to write
             // the string directly to the buffer, which should be common.
             int length = Utf8Encoding.GetByteCount(value);
-            WriteRawVarint32((uint)length);
+            WriteLength(length);
             if (limit - position >= length)
             {
                 if (length == value.Length) // Must be all ASCII...
@@ -262,23 +271,41 @@ namespace Google.Protobuf
             }
         }
 
+        /// <summary>
+        /// Writes a message, without a tag, to the stream.
+        /// The data is length-prefixed.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteMessage(IMessage value)
         {
             WriteRawVarint32((uint) value.CalculateSize());
             value.WriteTo(this);
         }
 
+        /// <summary>
+        /// Write a byte string, without a tag, to the stream.
+        /// The data is length-prefixed.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteBytes(ByteString value)
         {
             WriteRawVarint32((uint) value.Length);
             value.WriteRawBytesTo(this);
         }
 
+        /// <summary>
+        /// Writes a uint32 value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteUInt32(uint value)
         {
             WriteRawVarint32(value);
         }
 
+        /// <summary>
+        /// Writes an enum value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteEnum(int value)
         {
             WriteInt32(value);
@@ -289,27 +316,53 @@ namespace Google.Protobuf
             WriteRawLittleEndian32((uint) value);
         }
 
+        /// <summary>
+        /// Writes an sfixed64 value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteSFixed64(long value)
         {
             WriteRawLittleEndian64((ulong) value);
         }
 
+        /// <summary>
+        /// Writes an sint32 value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteSInt32(int value)
         {
             WriteRawVarint32(EncodeZigZag32(value));
         }
 
+        /// <summary>
+        /// Writes an sint64 value, without a tag, to the stream.
+        /// </summary>
+        /// <param name="value">The value to write</param>
         public void WriteSInt64(long value)
         {
             WriteRawVarint64(EncodeZigZag64(value));
         }
 
+        /// <summary>
+        /// Writes a length (in bytes) for length-delimited data.
+        /// </summary>
+        /// <remarks>
+        /// This method simply writes a rawint, but exists for clarity in calling code.
+        /// </remarks>
+        /// <param name="length">Length value, in bytes.</param>
+        public void WriteLength(int length)
+        {
+            WriteRawVarint32((uint) length);
+        }
+
         #endregion
 
         #region Raw tag writing
         /// <summary>
         /// Encodes and writes a tag.
         /// </summary>
+        /// <param name="fieldNumber">The number of the field to write the tag for</param>
+        /// <param name="type">The wire format type of the tag to write</param>
         public void WriteTag(int fieldNumber, WireFormat.WireType type)
         {
             WriteRawVarint32(WireFormat.MakeTag(fieldNumber, type));
@@ -318,6 +371,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes an already-encoded tag.
         /// </summary>
+        /// <param name="tag">The encoded tag</param>
         public void WriteTag(uint tag)
         {
             WriteRawVarint32(tag);
@@ -326,6 +380,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes the given single-byte tag directly to the stream.
         /// </summary>
+        /// <param name="b1">The encoded tag</param>
         public void WriteRawTag(byte b1)
         {
             WriteRawByte(b1);
@@ -334,6 +389,8 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes the given two-byte tag directly to the stream.
         /// </summary>
+        /// <param name="b1">The first byte of the encoded tag</param>
+        /// <param name="b2">The second byte of the encoded tag</param>
         public void WriteRawTag(byte b1, byte b2)
         {
             WriteRawByte(b1);
@@ -343,6 +400,9 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes the given three-byte tag directly to the stream.
         /// </summary>
+        /// <param name="b1">The first byte of the encoded tag</param>
+        /// <param name="b2">The second byte of the encoded tag</param>
+        /// <param name="b3">The third byte of the encoded tag</param>
         public void WriteRawTag(byte b1, byte b2, byte b3)
         {
             WriteRawByte(b1);
@@ -353,6 +413,10 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes the given four-byte tag directly to the stream.
         /// </summary>
+        /// <param name="b1">The first byte of the encoded tag</param>
+        /// <param name="b2">The second byte of the encoded tag</param>
+        /// <param name="b3">The third byte of the encoded tag</param>
+        /// <param name="b4">The fourth byte of the encoded tag</param>
         public void WriteRawTag(byte b1, byte b2, byte b3, byte b4)
         {
             WriteRawByte(b1);
@@ -364,6 +428,11 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes the given five-byte tag directly to the stream.
         /// </summary>
+        /// <param name="b1">The first byte of the encoded tag</param>
+        /// <param name="b2">The second byte of the encoded tag</param>
+        /// <param name="b3">The third byte of the encoded tag</param>
+        /// <param name="b4">The fourth byte of the encoded tag</param>
+        /// <param name="b5">The fifth byte of the encoded tag</param>
         public void WriteRawTag(byte b1, byte b2, byte b3, byte b4, byte b5)
         {
             WriteRawByte(b1);
@@ -380,7 +449,7 @@ namespace Google.Protobuf
         /// there's enough buffer space left to whizz through without checking
         /// for each byte; otherwise, we resort to calling WriteRawByte each time.
         /// </summary>
-        public void WriteRawVarint32(uint value)
+        internal void WriteRawVarint32(uint value)
         {
             // Optimize for the common case of a single byte value
             if (value < 128 && position < limit)
@@ -409,7 +478,7 @@ namespace Google.Protobuf
             }
         }
 
-        public void WriteRawVarint64(ulong value)
+        internal void WriteRawVarint64(ulong value)
         {
             while (value > 127 && position < limit)
             {
@@ -431,7 +500,7 @@ namespace Google.Protobuf
             }
         }
 
-        public void WriteRawLittleEndian32(uint value)
+        internal void WriteRawLittleEndian32(uint value)
         {
             if (position + 4 > limit)
             {
@@ -449,7 +518,7 @@ namespace Google.Protobuf
             }
         }
 
-        public void WriteRawLittleEndian64(ulong value)
+        internal void WriteRawLittleEndian64(ulong value)
         {
             if (position + 8 > limit)
             {
@@ -475,7 +544,7 @@ namespace Google.Protobuf
             }
         }
 
-        public void WriteRawByte(byte value)
+        internal void WriteRawByte(byte value)
         {
             if (position == limit)
             {
@@ -485,7 +554,7 @@ namespace Google.Protobuf
             buffer[position++] = value;
         }
 
-        public void WriteRawByte(uint value)
+        internal void WriteRawByte(uint value)
         {
             WriteRawByte((byte) value);
         }
@@ -493,7 +562,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes out an array of bytes.
         /// </summary>
-        public void WriteRawBytes(byte[] value)
+        internal void WriteRawBytes(byte[] value)
         {
             WriteRawBytes(value, 0, value.Length);
         }
@@ -501,7 +570,7 @@ namespace Google.Protobuf
         /// <summary>
         /// Writes out part of an array of bytes.
         /// </summary>
-        public void WriteRawBytes(byte[] value, int offset, int length)
+        internal void WriteRawBytes(byte[] value, int offset, int length)
         {
             if (limit - position >= length)
             {
@@ -548,7 +617,7 @@ namespace Google.Protobuf
         /// sign-extended to 64 bits to be varint encoded, thus always taking
         /// 10 bytes on the wire.)
         /// </remarks>
-        public static uint EncodeZigZag32(int n)
+        internal static uint EncodeZigZag32(int n)
         {
             // Note:  the right-shift must be arithmetic
             return (uint) ((n << 1) ^ (n >> 31));
@@ -563,7 +632,7 @@ namespace Google.Protobuf
         /// sign-extended to 64 bits to be varint encoded, thus always taking
         /// 10 bytes on the wire.)
         /// </remarks>
-        public static ulong EncodeZigZag64(long n)
+        internal static ulong EncodeZigZag64(long n)
         {
             return (ulong) ((n << 1) ^ (n >> 63));
         }

csharp/src/ProtocolBuffers/Collections/ReadOnlyDictionary.cs

@@ -38,7 +38,7 @@ namespace Google.Protobuf.Collections
     /// <summary>
     /// Read-only wrapper around another dictionary.
     /// </summary>
-    public sealed class ReadOnlyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
+    internal sealed class ReadOnlyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
     {
         private readonly IDictionary<TKey, TValue> wrapped;
 

csharp/src/ProtocolBuffers/Collections/RepeatedField.cs

@@ -51,12 +51,14 @@ namespace Google.Protobuf.Collections
 
         public void AddEntriesFrom(CodedInputStream input, FieldCodec<T> codec)
         {
+            // TODO: Inline some of the Add code, so we can avoid checking the size on every
+            // iteration and the mutability.
             uint tag = input.LastTag;
             var reader = codec.ValueReader;
             // Value types can be packed or not.
             if (typeof(T).IsValueType && WireFormat.GetTagWireType(tag) == WireFormat.WireType.LengthDelimited)
             {
-                int length = (int)(input.ReadRawVarint32() & int.MaxValue);
+                int length = input.ReadLength();
                 if (length > 0)
                 {
                     int oldLimit = input.PushLimit(length);
@@ -125,7 +127,6 @@ namespace Google.Protobuf.Collections
 
         public void WriteTo(CodedOutputStream output, FieldCodec<T> codec)
         {
-            // TODO: Assert that T is a value type, and that codec.Tag is packed?
             if (count == 0)
             {
                 return;
@@ -172,9 +173,9 @@ namespace Google.Protobuf.Collections
 
         private void EnsureSize(int size)
         {
-            size = Math.Max(size, MinArraySize);
             if (array.Length < size)
             {
+                size = Math.Max(size, MinArraySize);
                 int newSize = Math.Max(array.Length * 2, size);
                 var tmp = new T[newSize];
                 Array.Copy(array, 0, tmp, 0, array.Length);

csharp/src/ProtocolBuffers/FieldCodec.cs

@@ -8,6 +8,7 @@ namespace Google.Protobuf
     /// </summary>
     public static class FieldCodec
     {
+        // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...)
         public static FieldCodec<string> ForString(uint tag)
         {
             return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag); 
@@ -84,7 +85,7 @@ namespace Google.Protobuf
         }
 
         // Enums are tricky. We can probably use expression trees to build these delegates automatically,
-        // but it's easy to generate the code fdor it.
+        // but it's easy to generate the code for it.
         public static FieldCodec<T> ForEnum<T>(uint tag, Func<T, int> toInt32, Func<int, T> fromInt32)
         {
             return new FieldCodec<T>(input => fromInt32(

csharp/src/ProtocolBuffers/MessageExtensions.cs

@@ -38,7 +38,7 @@ namespace Google.Protobuf
         {
             ThrowHelper.ThrowIfNull(message, "message");
             ThrowHelper.ThrowIfNull(input, "input");
-            int size = (int)CodedInputStream.ReadRawVarint32(input);
+            int size = (int) CodedInputStream.ReadRawVarint32(input);
             Stream limitedStream = new LimitedInputStream(input, size);
             message.MergeFrom(limitedStream);
         }

csharp/src/ProtocolBuffers/Properties/AssemblyInfo.cs

@@ -61,6 +61,13 @@ using System.Security;
 
 [assembly: AssemblyVersion("2.4.1.555")]
 
+[assembly: InternalsVisibleTo("Google.Protobuf.Test, PublicKey=" +
+    "00240000048000009400000006020000002400005253413100040000110000003b4611704c5379" +
+    "39c3e0fbe9447dd6fa5462507f9dd4fd9fbf0712457e415b037da6d2c4eb5d2c7d29c86380af68" +
+    "7cf400401bb183f2a70bd3b631c1fcb7db8aa66c766694a9fb53fa765df6303104da8c978f3b6d" +
+    "53909cd30685b8bc9922c726cd82b5995e9e2cfca6df7a2d189d851492e49f4b76f269ce6dfd08" +
+    "c34a7d98")]
+
 #if !NOFILEVERSION
 [assembly: AssemblyFileVersion("2.4.1.555")]
 #endif

csharp/src/ProtocolBuffers/WireFormat.cs

@@ -53,13 +53,13 @@ namespace Google.Protobuf
         #region Fixed sizes.
 
         // TODO(jonskeet): Move these somewhere else. They're messy. Consider making FieldType a smarter kind of enum
-        public const int Fixed32Size = 4;
-        public const int Fixed64Size = 8;
-        public const int SFixed32Size = 4;
-        public const int SFixed64Size = 8;
-        public const int FloatSize = 4;
-        public const int DoubleSize = 8;
-        public const int BoolSize = 1;
+        internal const int Fixed32Size = 4;
+        internal const int Fixed64Size = 8;
+        internal const int SFixed32Size = 4;
+        internal const int SFixed64Size = 8;
+        internal const int FloatSize = 4;
+        internal const int DoubleSize = 8;
+        internal const int BoolSize = 1;
 
         #endregion
 
@@ -72,22 +72,7 @@ namespace Google.Protobuf
             EndGroup = 4,
             Fixed32 = 5
         }
-
-        internal static class MessageSetField
-        {
-            internal const int Item = 1;
-            internal const int TypeID = 2;
-            internal const int Message = 3;
-        }
-
-        internal static class MessageSetTag
-        {
-            internal static readonly uint ItemStart = MakeTag(MessageSetField.Item, WireType.StartGroup);
-            internal static readonly uint ItemEnd = MakeTag(MessageSetField.Item, WireType.EndGroup);
-            internal static readonly uint TypeID = MakeTag(MessageSetField.TypeID, WireType.Varint);
-            internal static readonly uint Message = MakeTag(MessageSetField.Message, WireType.LengthDelimited);
-        }
-
+        
         private const int TagTypeBits = 3;
         private const uint TagTypeMask = (1 << TagTypeBits) - 1;
 
@@ -120,7 +105,6 @@ namespace Google.Protobuf
             return (uint) (fieldNumber << TagTypeBits) | (uint) wireType;
         }
 
-#if !LITE
         public static uint MakeTag(FieldDescriptor field)
         {
             return MakeTag(field.FieldNumber, GetWireType(field));
@@ -135,8 +119,6 @@ namespace Google.Protobuf
             return descriptor.IsPacked ? WireType.LengthDelimited : GetWireType(descriptor.FieldType);
         }
 
-#endif
-
         /// <summary>
         /// Converts a field type to its wire type. Done with a switch for the sake
         /// of speed - this is significantly faster than a dictionary lookup.
@@ -177,7 +159,7 @@ namespace Google.Protobuf
                 case FieldType.Enum:
                     return WireType.Varint;
                 default:
-                    throw new ArgumentOutOfRangeException("No such field type");
+                    throw new ArgumentOutOfRangeException("fieldType", "No such field type");
             }
         }
     }