First cut at new layout

1 files changed, 765 insertions, 0 deletions

diff --git a/src/ProtocolBuffers/CodedOutputStream.cs b/src/ProtocolBuffers/CodedOutputStream.cs
new file mode 100644
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+++ b/src/ProtocolBuffers/CodedOutputStream.cs
@@ -0,0 +1,765 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.
+// http://code.google.com/p/protobuf/
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+using System;
+using System.IO;
+using System.Text;
+using Google.ProtocolBuffers.Descriptors;
+
+namespace Google.ProtocolBuffers {
+
+  /// <summary>
+  /// Encodes and writes protocol message fields.
+  /// </summary>
+  /// <remarks>
+  /// This class contains two kinds of methods:  methods that write specific
+  /// protocol message constructs and field types (e.g. WriteTag and
+  /// WriteInt32) and methods that write low-level values (e.g.
+  /// WriteRawVarint32 and WriteRawBytes).  If you are writing encoded protocol
+  /// messages, you should use the former methods, but if you are writing some
+  /// other format of your own design, use the latter. The names of the former
+  /// methods are taken from the protocol buffer type names, not .NET types.
+  /// (Hence WriteFloat instead of WriteSingle, and WriteBool instead of WriteBoolean.)
+  /// </remarks>
+  public sealed class CodedOutputStream {
+    /// <summary>
+    /// The buffer size used by CreateInstance(Stream).
+    /// </summary>
+    public static readonly int DefaultBufferSize = 4096;
+
+    private readonly byte[] buffer;
+    private readonly int limit;
+    private int position;
+    private readonly Stream output;
+
+    #region Construction
+    private CodedOutputStream(byte[] buffer, int offset, int length) {
+      this.output = null;
+      this.buffer = buffer;
+      this.position = offset;
+      this.limit = offset + length;
+    }
+
+    private CodedOutputStream(Stream output, byte[] buffer) {
+      this.output = output;
+      this.buffer = buffer;
+      this.position = 0;
+      this.limit = buffer.Length;
+    }
+
+    /// <summary>
+    /// Creates a new CodedOutputStream which write to the given stream.
+    /// </summary>
+    public static CodedOutputStream CreateInstance(Stream output) {
+      return CreateInstance(output, DefaultBufferSize);
+    }
+
+    /// <summary>
+    /// Creates a new CodedOutputStream which write to the given stream and uses
+    /// the specified buffer size.
+    /// </summary>
+    public static CodedOutputStream CreateInstance(Stream output, int bufferSize) {
+      return new CodedOutputStream(output, new byte[bufferSize]);
+    }
+
+    /// <summary>
+    /// Creates a new CodedOutputStream that writes directly to the given
+    /// byte array. If more bytes are written than fit in the array,
+    /// OutOfSpaceException will be thrown.
+    /// </summary>
+    public static CodedOutputStream CreateInstance(byte[] flatArray) {
+      return CreateInstance(flatArray, 0, flatArray.Length);
+    }
+
+    /// <summary>
+    /// Creates a new CodedOutputStream that writes directly to the given
+    /// byte array slice. If more bytes are written than fit in the array,
+    /// OutOfSpaceException will be thrown.
+    /// </summary>
+    public static CodedOutputStream CreateInstance(byte[] flatArray, int offset, int length) {
+      return new CodedOutputStream(flatArray, offset, length);
+    }
+    #endregion
+
+    #region Writing of tags etc
+    /// <summary>
+    /// Writes a double field value, including tag, to the stream.
+    /// </summary>
+    public void WriteDouble(int fieldNumber, double value) {
+      // TODO(jonskeet): Test this on different endiannesses
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed64);
+      WriteRawLittleEndian64((ulong)BitConverter.DoubleToInt64Bits(value));
+    }
+
+    /// <summary>
+    /// Writes a float field value, including tag, to the stream.
+    /// </summary>
+    public void WriteFloat(int fieldNumber, float value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed32);
+      // TODO(jonskeet): Test this on different endiannesses
+      byte[] rawBytes = BitConverter.GetBytes(value);
+      uint asInteger = BitConverter.ToUInt32(rawBytes, 0);
+      WriteRawLittleEndian32(asInteger);
+    }
+
+    /// <summary>
+    /// Writes a uint64 field value, including tag, to the stream.
+    /// </summary>
+    public void WriteUInt64(int fieldNumber, ulong value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint64(value);
+    }
+
+    /// <summary>
+    /// Writes an int64 field value, including tag, to the stream.
+    /// </summary>
+    public void WriteInt64(int fieldNumber, long value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint64((ulong)value);
+    }
+
+    /// <summary>
+    /// Writes an int32 field value, including tag, to the stream.
+    /// </summary>
+    public void WriteInt32(int fieldNumber, int value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      if (value >= 0) {
+        WriteRawVarint32((uint)value);
+      } else {
+        // Must sign-extend.
+        WriteRawVarint64((ulong)value);
+      }
+    }
+
+    /// <summary>
+    /// Writes a fixed64 field value, including tag, to the stream.
+    /// </summary>
+    public void WriteFixed64(int fieldNumber, ulong value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed64);
+      WriteRawLittleEndian64(value);
+    }
+
+    /// <summary>
+    /// Writes a fixed32 field value, including tag, to the stream.
+    /// </summary>
+    public void WriteFixed32(int fieldNumber, uint value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed32);
+      WriteRawLittleEndian32(value);
+    }
+
+    /// <summary>
+    /// Writes a bool field value, including tag, to the stream.
+    /// </summary>
+    public void WriteBool(int fieldNumber, bool value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawByte(value ? (byte)1 : (byte)0);
+    }
+
+    /// <summary>
+    /// Writes a string field value, including tag, to the stream.
+    /// </summary>
+    public void WriteString(int fieldNumber, string value) {
+      WriteTag(fieldNumber, WireFormat.WireType.LengthDelimited);
+      // Optimise the case where we have enough space to write
+      // the string directly to the buffer, which should be common.
+      int length = Encoding.UTF8.GetByteCount(value);
+      WriteRawVarint32((uint) length);
+      if (limit - position >= length) {
+        Encoding.UTF8.GetBytes(value, 0, value.Length, buffer, position);
+        position += length;
+      } else {
+        byte[] bytes = Encoding.UTF8.GetBytes(value);
+        WriteRawBytes(bytes);
+      }
+    }
+
+    /// <summary>
+    /// Writes a group field value, including tag, to the stream.
+    /// </summary>
+    public void WriteGroup(int fieldNumber, IMessage value) {
+      WriteTag(fieldNumber, WireFormat.WireType.StartGroup);
+      value.WriteTo(this);
+      WriteTag(fieldNumber, WireFormat.WireType.EndGroup);
+    }
+
+    public void WriteUnknownGroup(int fieldNumber, UnknownFieldSet value) {
+      WriteTag(fieldNumber, WireFormat.WireType.StartGroup);
+      value.WriteTo(this);
+      WriteTag(fieldNumber, WireFormat.WireType.EndGroup);
+    }
+
+    public void WriteMessage(int fieldNumber, IMessage value) {
+      WriteTag(fieldNumber, WireFormat.WireType.LengthDelimited);
+      WriteRawVarint32((uint)value.SerializedSize);
+      value.WriteTo(this);
+    }
+
+    public void WriteBytes(int fieldNumber, ByteString value) {
+      // TODO(jonskeet): Optimise this! (No need to copy the bytes twice.)
+      WriteTag(fieldNumber, WireFormat.WireType.LengthDelimited);
+      byte[] bytes = value.ToByteArray();
+      WriteRawVarint32((uint)bytes.Length);
+      WriteRawBytes(bytes);
+    }
+
+    public void WriteUInt32(int fieldNumber, uint value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint32(value);
+    }
+
+    public void WriteEnum(int fieldNumber, int value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint32((uint)value);
+    }
+
+    public void WriteSFixed32(int fieldNumber, int value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed32);
+      WriteRawLittleEndian32((uint)value);
+    }
+
+    public void WriteSFixed64(int fieldNumber, long value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Fixed64);
+      WriteRawLittleEndian64((ulong)value);
+    }
+
+    public void WriteSInt32(int fieldNumber, int value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint32(EncodeZigZag32(value));
+    }
+
+    public void WriteSInt64(int fieldNumber, long value) {
+      WriteTag(fieldNumber, WireFormat.WireType.Varint);
+      WriteRawVarint64(EncodeZigZag64(value));
+    }
+
+    public void WriteMessageSetExtension(int fieldNumber, IMessage value) {
+      WriteTag(WireFormat.MessageSetField.Item, WireFormat.WireType.StartGroup);
+      WriteUInt32(WireFormat.MessageSetField.TypeID, (uint)fieldNumber);
+      WriteMessage(WireFormat.MessageSetField.Message, value);
+      WriteTag(WireFormat.MessageSetField.Item, WireFormat.WireType.EndGroup);
+    }
+
+    public void WriteRawMessageSetExtension(int fieldNumber, ByteString value) {
+      WriteTag(WireFormat.MessageSetField.Item, WireFormat.WireType.StartGroup);
+      WriteUInt32(WireFormat.MessageSetField.TypeID, (uint)fieldNumber);
+      WriteBytes(WireFormat.MessageSetField.Message, value);
+      WriteTag(WireFormat.MessageSetField.Item, WireFormat.WireType.EndGroup);
+    }
+
+    public void WriteField(FieldType fieldType, int fieldNumber, object value) {
+      switch (fieldType) {
+        case FieldType.Double: WriteDouble(fieldNumber, (double)value); break;
+        case FieldType.Float: WriteFloat(fieldNumber, (float)value); break;
+        case FieldType.Int64: WriteInt64(fieldNumber, (long)value); break;
+        case FieldType.UInt64: WriteUInt64(fieldNumber, (ulong)value); break;
+        case FieldType.Int32: WriteInt32(fieldNumber, (int)value); break;
+        case FieldType.Fixed64: WriteFixed64(fieldNumber, (ulong)value); break;
+        case FieldType.Fixed32: WriteFixed32(fieldNumber, (uint)value); break;
+        case FieldType.Bool: WriteBool(fieldNumber, (bool)value); break;
+        case FieldType.String: WriteString(fieldNumber, (string)value); break;
+        case FieldType.Group: WriteGroup(fieldNumber, (IMessage)value); break;
+        case FieldType.Message: WriteMessage(fieldNumber, (IMessage)value); break;
+        case FieldType.Bytes: WriteBytes(fieldNumber, (ByteString)value); break;
+        case FieldType.UInt32: WriteUInt32(fieldNumber, (uint)value); break;
+        case FieldType.SFixed32: WriteSFixed32(fieldNumber, (int)value); break;
+        case FieldType.SFixed64: WriteSFixed64(fieldNumber, (long)value); break;
+        case FieldType.SInt32: WriteSInt32(fieldNumber, (int)value); break;
+        case FieldType.SInt64: WriteSInt64(fieldNumber, (long)value); break;
+        case FieldType.Enum: WriteEnum(fieldNumber, ((EnumValueDescriptor)value).Number);
+          break;
+      }
+    }
+
+    #endregion
+
+    #region Underlying writing primitives
+    /// <summary>
+    /// Encodes and writes a tag.
+    /// </summary>
+    public void WriteTag(int fieldNumber, WireFormat.WireType type) {
+      WriteRawVarint32(WireFormat.MakeTag(fieldNumber, type));
+    }
+
+    private void SlowWriteRawVarint32(uint value) {
+      while (true) {
+        if ((value & ~0x7F) == 0) {
+          WriteRawByte(value);
+          return;
+        } else {
+          WriteRawByte((value & 0x7F) | 0x80);
+          value >>= 7;
+        }
+      }
+    }
+
+    /// <summary>
+    /// Writes a 32 bit value as a varint. The fast route is taken when
+    /// 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) {
+      if (position + 5 > limit) {
+        SlowWriteRawVarint32(value);
+        return;
+      }
+
+      while (true) {
+        if ((value & ~0x7F) == 0) {
+          buffer[position++] = (byte) value;
+          return;
+        } else {
+          buffer[position++] = (byte)((value & 0x7F) | 0x80);
+          value >>= 7;
+        }
+      }
+    }
+
+    public void WriteRawVarint64(ulong value) {
+      while (true) {
+        if ((value & ~0x7FUL) == 0) {
+          WriteRawByte((uint)value);
+          return;
+        } else {
+          WriteRawByte(((uint)value & 0x7F) | 0x80);
+          value >>= 7;
+        }
+      }
+    }
+
+    public void WriteRawLittleEndian32(uint value) {
+      WriteRawByte((byte)value);
+      WriteRawByte((byte)(value >> 8));
+      WriteRawByte((byte)(value >> 16));
+      WriteRawByte((byte)(value >> 24));
+    }
+
+    public void WriteRawLittleEndian64(ulong value) {
+      WriteRawByte((byte)value);
+      WriteRawByte((byte)(value >> 8));
+      WriteRawByte((byte)(value >> 16));
+      WriteRawByte((byte)(value >> 24));
+      WriteRawByte((byte)(value >> 32));
+      WriteRawByte((byte)(value >> 40));
+      WriteRawByte((byte)(value >> 48));
+      WriteRawByte((byte)(value >> 56));
+    }
+
+    public void WriteRawByte(byte value) {
+      if (position == limit) {
+        RefreshBuffer();
+      }
+
+      buffer[position++] = value;
+    }
+
+    public void WriteRawByte(uint value) {
+      WriteRawByte((byte)value);
+    }
+
+    /// <summary>
+    /// Writes out an array of bytes.
+    /// </summary>
+    public void WriteRawBytes(byte[] value) {
+      WriteRawBytes(value, 0, value.Length);
+    }
+
+    /// <summary>
+    /// Writes out part of an array of bytes.
+    /// </summary>
+    public void WriteRawBytes(byte[] value, int offset, int length) {
+      if (limit - position >= length) {
+        Array.Copy(value, offset, buffer, position, length);
+        // We have room in the current buffer.
+        position += length;
+      } else {
+        // Write extends past current buffer.  Fill the rest of this buffer and
+        // flush.
+        int bytesWritten = limit - position;
+        Array.Copy(value, offset, buffer, position, bytesWritten);
+        offset += bytesWritten;
+        length -= bytesWritten;
+        position = limit;
+        RefreshBuffer();
+
+        // Now deal with the rest.
+        // Since we have an output stream, this is our buffer
+        // and buffer offset == 0
+        if (length <= limit) {
+          // Fits in new buffer.
+          Array.Copy(value, offset, buffer, 0, length);
+          position = length;
+        } else {
+          // Write is very big.  Let's do it all at once.
+          output.Write(value, offset, length);
+        }
+      }
+    }
+    #endregion
+
+    #region Size computations
+
+    const int LittleEndian64Size = 8;
+    const int LittleEndian32Size = 4;
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// double field, including the tag.
+    /// </summary>
+    public static int ComputeDoubleSize(int fieldNumber, double value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian64Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// float field, including the tag.
+    /// </summary>
+    public static int ComputeFloatSize(int fieldNumber, float value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian32Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// uint64 field, including the tag.
+    /// </summary>
+    public static int ComputeUInt64Size(int fieldNumber, ulong value) {
+      return ComputeTagSize(fieldNumber) + ComputeRawVarint64Size(value);
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// int64 field, including the tag.
+    /// </summary>
+    public static int ComputeInt64Size(int fieldNumber, long value) {
+      return ComputeTagSize(fieldNumber) + ComputeRawVarint64Size((ulong)value);
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// int32 field, including the tag.
+    /// </summary>
+    public static int ComputeInt32Size(int fieldNumber, int value) {
+      if (value >= 0) {
+        return ComputeTagSize(fieldNumber) + ComputeRawVarint32Size((uint)value);
+      } else {
+        // Must sign-extend.
+        return ComputeTagSize(fieldNumber) + 10;
+      }
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// fixed64 field, including the tag.
+    /// </summary>
+    public static int ComputeFixed64Size(int fieldNumber, ulong value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian64Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// fixed32 field, including the tag.
+    /// </summary>
+    public static int ComputeFixed32Size(int fieldNumber, uint value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian32Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// bool field, including the tag.
+    /// </summary>
+    public static int ComputeBoolSize(int fieldNumber, bool value) {
+      return ComputeTagSize(fieldNumber) + 1;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// string field, including the tag.
+    /// </summary>
+    public static int ComputeStringSize(int fieldNumber, String value) {
+      int byteArraySize = Encoding.UTF8.GetByteCount(value);
+      return ComputeTagSize(fieldNumber) +
+             ComputeRawVarint32Size((uint)byteArraySize) +
+             byteArraySize;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// group field, including the tag.
+    /// </summary>
+    public static int ComputeGroupSize(int fieldNumber, IMessage value) {
+      return ComputeTagSize(fieldNumber) * 2 + value.SerializedSize;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// group field represented by an UnknownFieldSet, including the tag.
+    /// </summary>
+    public static int ComputeUnknownGroupSize(int fieldNumber,
+                                              UnknownFieldSet value) {
+      return ComputeTagSize(fieldNumber) * 2 + value.SerializedSize;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// embedded message field, including the tag.
+    /// </summary>
+    public static int ComputeMessageSize(int fieldNumber, IMessage value) {
+      int size = value.SerializedSize;
+      return ComputeTagSize(fieldNumber) + ComputeRawVarint32Size((uint)size) + size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// bytes field, including the tag.
+    /// </summary>
+    public static int ComputeBytesSize(int fieldNumber, ByteString value) {
+      return ComputeTagSize(fieldNumber) +
+             ComputeRawVarint32Size((uint)value.Length) +
+             value.Length;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// uint32 field, including the tag.
+    /// </summary>
+    public static int ComputeUInt32Size(int fieldNumber, uint value) {
+      return ComputeTagSize(fieldNumber) + ComputeRawVarint32Size(value);
+    }
+
+    /// <summary>
+    /// Compute 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>
+    public static int ComputeEnumSize(int fieldNumber, int value) {
+      return ComputeTagSize(fieldNumber) + ComputeRawVarint32Size((uint)value);
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// sfixed32 field, including the tag.
+    /// </summary>
+    public static int ComputeSFixed32Size(int fieldNumber, int value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian32Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// sfixed64 field, including the tag.
+    /// </summary>
+    public static int ComputeSFixed64Size(int fieldNumber, long value) {
+      return ComputeTagSize(fieldNumber) + LittleEndian64Size;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// sint32 field, including the tag.
+    /// </summary>
+    public static int ComputeSInt32Size(int fieldNumber, int value) {
+      return ComputeTagSize(fieldNumber) +
+             ComputeRawVarint32Size(EncodeZigZag32(value));
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// sint64 field, including the tag.
+    /// </summary>
+    public static int ComputeSInt64Size(int fieldNumber, long value) {
+      return ComputeTagSize(fieldNumber) +
+             ComputeRawVarint64Size(EncodeZigZag64(value));
+    }
+
+    /*
+     * Compute the number of bytes that would be needed to encode a
+     * MessageSet extension to the stream.  For historical reasons,
+     * the wire format differs from normal fields.
+     */
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a
+    /// MessageSet extension to the stream. For historical reasons,
+    /// the wire format differs from normal fields.
+    /// </summary>
+    public static int ComputeMessageSetExtensionSize(int fieldNumber, IMessage value) {
+      return ComputeTagSize(WireFormat.MessageSetField.Item) * 2 +
+             ComputeUInt32Size(WireFormat.MessageSetField.TypeID, (uint) fieldNumber) +
+             ComputeMessageSize(WireFormat.MessageSetField.Message, value);
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode an
+    /// unparsed MessageSet extension field to the stream. For
+    /// historical reasons, the wire format differs from normal fields.
+    /// </summary>
+    public static int ComputeRawMessageSetExtensionSize(int fieldNumber, ByteString value) {
+      return ComputeTagSize(WireFormat.MessageSetField.Item) * 2 +
+             ComputeUInt32Size(WireFormat.MessageSetField.TypeID, (uint) fieldNumber) +
+             ComputeBytesSize(WireFormat.MessageSetField.Message, value);
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a varint.
+    /// </summary>
+    public static int ComputeRawVarint32Size(uint value) {
+      if ((value & (0xffffffff << 7)) == 0) return 1;
+      if ((value & (0xffffffff << 14)) == 0) return 2;
+      if ((value & (0xffffffff << 21)) == 0) return 3;
+      if ((value & (0xffffffff << 28)) == 0) return 4;
+      return 5;
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a varint.
+    /// </summary>
+    public static int ComputeRawVarint64Size(ulong value) {
+      if ((value & (0xffffffffffffffffL << 7)) == 0) return 1;
+      if ((value & (0xffffffffffffffffL << 14)) == 0) return 2;
+      if ((value & (0xffffffffffffffffL << 21)) == 0) return 3;
+      if ((value & (0xffffffffffffffffL << 28)) == 0) return 4;
+      if ((value & (0xffffffffffffffffL << 35)) == 0) return 5;
+      if ((value & (0xffffffffffffffffL << 42)) == 0) return 6;
+      if ((value & (0xffffffffffffffffL << 49)) == 0) return 7;
+      if ((value & (0xffffffffffffffffL << 56)) == 0) return 8;
+      if ((value & (0xffffffffffffffffL << 63)) == 0) return 9;
+      return 10;
+    }
+
+
+    /*
+     * Compute the number of bytes that would be needed to encode a
+     * field of arbitrary type, including tag, to the stream.
+     *
+     * @param type   The field's type.
+     * @param number The field's number.
+     * @param value  Object representing the field's value.  Must be of the exact
+     *               type which would be returned by
+     *               {@link Message#getField(FieldDescriptor)} for
+     *               this field.
+     */
+    public static int ComputeFieldSize(FieldType fieldType, int fieldNumber, Object value) {
+      switch (fieldType) {
+        case FieldType.Double: return ComputeDoubleSize(fieldNumber, (double)value);
+        case FieldType.Float: return ComputeFloatSize(fieldNumber, (float)value);
+        case FieldType.Int64: return ComputeInt64Size(fieldNumber, (long)value);
+        case FieldType.UInt64: return ComputeUInt64Size(fieldNumber, (ulong)value);
+        case FieldType.Int32: return ComputeInt32Size(fieldNumber, (int)value);
+        case FieldType.Fixed64: return ComputeFixed64Size(fieldNumber, (ulong)value);
+        case FieldType.Fixed32: return ComputeFixed32Size(fieldNumber, (uint)value);
+        case FieldType.Bool: return ComputeBoolSize(fieldNumber, (bool)value);
+        case FieldType.String: return ComputeStringSize(fieldNumber, (string)value);
+        case FieldType.Group: return ComputeGroupSize(fieldNumber, (IMessage)value);
+        case FieldType.Message: return ComputeMessageSize(fieldNumber, (IMessage)value);
+        case FieldType.Bytes: return ComputeBytesSize(fieldNumber, (ByteString)value);
+        case FieldType.UInt32: return ComputeUInt32Size(fieldNumber, (uint)value);
+        case FieldType.SFixed32: return ComputeSFixed32Size(fieldNumber, (int)value);
+        case FieldType.SFixed64: return ComputeSFixed64Size(fieldNumber, (long)value);
+        case FieldType.SInt32: return ComputeSInt32Size(fieldNumber, (int)value);
+        case FieldType.SInt64: return ComputeSInt64Size(fieldNumber, (long)value);
+        case FieldType.Enum: return ComputeEnumSize(fieldNumber, ((EnumValueDescriptor)value).Number);
+        default:
+          throw new ArgumentOutOfRangeException("Invalid field type " + fieldType);
+      }
+    }
+
+    /// <summary>
+    /// Compute the number of bytes that would be needed to encode a tag.
+    /// </summary>
+    public static int ComputeTagSize(int fieldNumber) {
+      return ComputeRawVarint32Size(WireFormat.MakeTag(fieldNumber, 0));
+    }
+    #endregion
+
+    /// <summary>
+    /// Encode a 32-bit value with ZigZag encoding.
+    /// </summary>
+    /// <remarks>
+    /// ZigZag encodes signed integers into values that can be efficiently
+    /// encoded with varint.  (Otherwise, negative values must be 
+    /// sign-extended to 64 bits to be varint encoded, thus always taking
+    /// 10 bytes on the wire.)
+    /// </remarks>
+    public static uint EncodeZigZag32(int n) {
+      // Note:  the right-shift must be arithmetic
+      return (uint)((n << 1) ^ (n >> 31));
+    }
+
+    /// <summary>
+    /// Encode a 64-bit value with ZigZag encoding.
+    /// </summary>
+    /// <remarks>
+    /// ZigZag encodes signed integers into values that can be efficiently
+    /// encoded with varint.  (Otherwise, negative values must be 
+    /// sign-extended to 64 bits to be varint encoded, thus always taking
+    /// 10 bytes on the wire.)
+    /// </remarks>
+    public static ulong EncodeZigZag64(long n) {
+      return (ulong)((n << 1) ^ (n >> 63));
+    }
+
+    private void RefreshBuffer() {
+      if (output == null) {
+        // We're writing to a single buffer.
+        throw new OutOfSpaceException();
+      }
+
+      // Since we have an output stream, this is our buffer
+      // and buffer offset == 0
+      output.Write(buffer, 0, position);
+      position = 0;
+    }
+
+    /// <summary>
+    /// Indicates that a CodedOutputStream wrapping a flat byte array
+    /// ran out of space.
+    /// </summary>
+    public sealed class OutOfSpaceException : IOException {
+      internal OutOfSpaceException()
+        : base("CodedOutputStream was writing to a flat byte array and ran out of space.") {
+      }
+    }
+
+    public void Flush() {
+      if (output != null) {
+        RefreshBuffer();
+      }
+    }
+
+    /// <summary>
+    /// Verifies that SpaceLeft returns zero. It's common to create a byte array
+    /// that is exactly big enough to hold a message, then write to it with
+    /// a CodedOutputStream. Calling CheckNoSpaceLeft after writing verifies that
+    /// the message was actually as big as expected, which can help bugs.
+    /// </summary>
+    public void CheckNoSpaceLeft() {
+      if (SpaceLeft != 0) {
+        throw new InvalidOperationException("Did not write as much data as expected.");
+      }
+    }
+
+    /// <summary>
+    /// If writing to a flat array, returns the space left in the array. Otherwise,
+    /// throws an InvalidOperationException.
+    /// </summary>
+    public int SpaceLeft {
+      get {
+        if (output == null) {
+          return limit - position;
+        } else {
+          throw new InvalidOperationException(
+            "SpaceLeft can only be called on CodedOutputStreams that are " +
+            "writing to a flat array.");
+        }
+      }
+    }
+  }
+}
\ No newline at end of file