csharp/src/Google.Protobuf/CodedOutputStream.cs - third_party/protobuf - Git at Google

 #region Copyright notice and license
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 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 Google.Protobuf.Collections;
 using System;
 using System.IO;
 using System.Text;

 namespace Google.Protobuf
 {
     /// <summary>
     /// Encodes and writes protocol message fields.
     /// </summary>
     /// <remarks>
     /// <para>
     /// This class is generally used by generated code to write appropriate
     /// primitives to the stream. It effectively encapsulates the lowest
     /// levels of protocol buffer format. Unlike some other implementations,
     /// this does not include combined "write tag and value" methods. Generated
     /// code knows the exact byte representations of the tags they're going to write,
     /// so there's no need to re-encode them each time. Manually-written code calling
     /// this class should just call one of the <c>WriteTag</c> overloads before each value.
     /// </para>
     /// <para>
     /// Repeated fields and map fields are not handled by this class; use <c>RepeatedField&lt;T&gt;</c>
     /// and <c>MapField&lt;TKey, TValue&gt;</c> to serialize such fields.
     /// </para>
     /// </remarks>
     public sealed partial class CodedOutputStream : IDisposable
     {
         // "Local" copy of Encoding.UTF8, for efficiency. (Yes, it makes a difference.)
         internal static readonly Encoding Utf8Encoding = Encoding.UTF8;

         /// <summary>
         /// The buffer size used by CreateInstance(Stream).
         /// </summary>
         public static readonly int DefaultBufferSize = 4096;

         private readonly bool leaveOpen;
         private readonly byte[] buffer;
         private readonly int limit;
         private int position;
         private readonly Stream output;

         #region Construction
         /// <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 CodedOutputStream(byte[] flatArray) : this(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>
         private CodedOutputStream(byte[] buffer, int offset, int length)
         {
             this.output = null;
             this.buffer = buffer;
             this.position = offset;
             this.limit = offset + length;
             leaveOpen = true; // Simple way of avoiding trying to dispose of a null reference
         }

         private CodedOutputStream(Stream output, byte[] buffer, bool leaveOpen)
         {
             this.output = ProtoPreconditions.CheckNotNull(output, nameof(output));
             this.buffer = buffer;
             this.position = 0;
             this.limit = buffer.Length;
             this.leaveOpen = leaveOpen;
         }

         /// <summary>
         /// Creates a new <see cref="CodedOutputStream" /> which write to the given stream, and disposes of that
         /// stream when the returned <c>CodedOutputStream</c> is disposed.
         /// </summary>
         /// <param name="output">The stream to write to. It will be disposed when the returned <c>CodedOutputStream is disposed.</c></param>
         public CodedOutputStream(Stream output) : this(output, DefaultBufferSize, false)
         {
         }

         /// <summary>
         /// Creates a new CodedOutputStream which write to the given stream and uses
         /// the specified buffer size.
         /// </summary>
         /// <param name="output">The stream to write to. It will be disposed when the returned <c>CodedOutputStream is disposed.</c></param>
         /// <param name="bufferSize">The size of buffer to use internally.</param>
         public CodedOutputStream(Stream output, int bufferSize) : this(output, new byte[bufferSize], false)
         {
         }

         /// <summary>
         /// Creates a new CodedOutputStream which write to the given stream.
         /// </summary>
         /// <param name="output">The stream to write to.</param>
         /// <param name="leaveOpen">If <c>true</c>, <paramref name="output"/> is left open when the returned <c>CodedOutputStream</c> is disposed;
         /// if <c>false</c>, the provided stream is disposed as well.</param>
         public CodedOutputStream(Stream output, bool leaveOpen) : this(output, DefaultBufferSize, leaveOpen)
         {
         }

         /// <summary>
         /// Creates a new CodedOutputStream which write to the given stream and uses
         /// the specified buffer size.
         /// </summary>
         /// <param name="output">The stream to write to.</param>
         /// <param name="bufferSize">The size of buffer to use internally.</param>
         /// <param name="leaveOpen">If <c>true</c>, <paramref name="output"/> is left open when the returned <c>CodedOutputStream</c> is disposed;
         /// if <c>false</c>, the provided stream is disposed as well.</param>
         public CodedOutputStream(Stream output, int bufferSize, bool leaveOpen) : this(output, new byte[bufferSize], leaveOpen)
         {
         }
         #endregion

         /// <summary>
         /// Returns the current position in the stream, or the position in the output buffer
         /// </summary>
         public long Position
         {
             get
             {
                 if (output != null)
                 {
                     return output.Position + position;
                 }
                 return position;
             }
         }

         #region Writing of values (not including tags)

         /// <summary>
         /// 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));
         }

         /// <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);
             if (!BitConverter.IsLittleEndian)
             {
                 ByteArray.Reverse(rawBytes);
             }

             if (limit - position >= 4)
             {
                 buffer[position++] = rawBytes[0];
                 buffer[position++] = rawBytes[1];
                 buffer[position++] = rawBytes[2];
                 buffer[position++] = rawBytes[3];
             }
             else
             {
                 WriteRawBytes(rawBytes, 0, 4);
             }
         }

         /// <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);
         }

         /// <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);
         }

         /// <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)
             {
                 WriteRawVarint32((uint) value);
             }
             else
             {
                 // Must sign-extend.
                 WriteRawVarint64((ulong) value);
             }
         }

         /// <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);
         }

         /// <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);
         }

         /// <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);
         }

         /// <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);
             WriteLength(length);
             if (limit - position >= length)
             {
                 if (length == value.Length) // Must be all ASCII...
                 {
                     for (int i = 0; i < length; i++)
                     {
                         buffer[position + i] = (byte)value[i];
                     }
                 }
                 else
                 {
                     Utf8Encoding.GetBytes(value, 0, value.Length, buffer, position);
                 }
                 position += length;
             }
             else
             {
                 byte[] bytes = Utf8Encoding.GetBytes(value);
                 WriteRawBytes(bytes);
             }
         }

         /// <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)
         {
             WriteLength(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)
         {
             WriteLength(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);
         }

         /// <summary>
         /// Writes an sfixed32 value, without a tag, to the stream.
         /// </summary>
         /// <param name="value">The value to write.</param>
         public void WriteSFixed32(int value)
         {
             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));
         }

         /// <summary>
         /// Writes an already-encoded tag.
         /// </summary>
         /// <param name="tag">The encoded tag</param>
         public void WriteTag(uint tag)
         {
             WriteRawVarint32(tag);
         }

         /// <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);
         }

         /// <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);
             WriteRawByte(b2);
         }

         /// <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);
             WriteRawByte(b2);
             WriteRawByte(b3);
         }

         /// <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);
             WriteRawByte(b2);
             WriteRawByte(b3);
             WriteRawByte(b4);
         }

         /// <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);
             WriteRawByte(b2);
             WriteRawByte(b3);
             WriteRawByte(b4);
             WriteRawByte(b5);
         }
         #endregion

         #region Underlying writing primitives
         /// <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>
         internal void WriteRawVarint32(uint value)
         {
             // Optimize for the common case of a single byte value
             if (value < 128 && position < limit)
             {
                 buffer[position++] = (byte)value;
                 return;
             }

             while (value > 127 && position < limit)
             {
                 buffer[position++] = (byte) ((value & 0x7F) | 0x80);
                 value >>= 7;
             }
             while (value > 127)
             {
                 WriteRawByte((byte) ((value & 0x7F) | 0x80));
                 value >>= 7;
             }
             if (position < limit)
             {
                 buffer[position++] = (byte) value;
             }
             else
             {
                 WriteRawByte((byte) value);
             }
         }

         internal void WriteRawVarint64(ulong value)
         {
             while (value > 127 && position < limit)
             {
                 buffer[position++] = (byte) ((value & 0x7F) | 0x80);
                 value >>= 7;
             }
             while (value > 127)
             {
                 WriteRawByte((byte) ((value & 0x7F) | 0x80));
                 value >>= 7;
             }
             if (position < limit)
             {
                 buffer[position++] = (byte) value;
             }
             else
             {
                 WriteRawByte((byte) value);
             }
         }

         internal void WriteRawLittleEndian32(uint value)
         {
             if (position + 4 > limit)
             {
                 WriteRawByte((byte) value);
                 WriteRawByte((byte) (value >> 8));
                 WriteRawByte((byte) (value >> 16));
                 WriteRawByte((byte) (value >> 24));
             }
             else
             {
                 buffer[position++] = ((byte) value);
                 buffer[position++] = ((byte) (value >> 8));
                 buffer[position++] = ((byte) (value >> 16));
                 buffer[position++] = ((byte) (value >> 24));
             }
         }

         internal void WriteRawLittleEndian64(ulong value)
         {
             if (position + 8 > limit)
             {
                 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));
             }
             else
             {
                 buffer[position++] = ((byte) value);
                 buffer[position++] = ((byte) (value >> 8));
                 buffer[position++] = ((byte) (value >> 16));
                 buffer[position++] = ((byte) (value >> 24));
                 buffer[position++] = ((byte) (value >> 32));
                 buffer[position++] = ((byte) (value >> 40));
                 buffer[position++] = ((byte) (value >> 48));
                 buffer[position++] = ((byte) (value >> 56));
             }
         }

         internal void WriteRawByte(byte value)
         {
             if (position == limit)
             {
                 RefreshBuffer();
             }

             buffer[position++] = value;
         }

         internal void WriteRawByte(uint value)
         {
             WriteRawByte((byte) value);
         }

         /// <summary>
         /// Writes out an array of bytes.
         /// </summary>
         internal void WriteRawBytes(byte[] value)
         {
             WriteRawBytes(value, 0, value.Length);
         }

         /// <summary>
         /// Writes out part of an array of bytes.
         /// </summary>
         internal void WriteRawBytes(byte[] value, int offset, int length)
         {
             if (limit - position >= length)
             {
                 ByteArray.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;
                 ByteArray.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.
                     ByteArray.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

         /// <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>
         internal 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>
         internal 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.")
             {
             }
         }

         /// <summary>
         /// Flushes any buffered data and optionally closes the underlying stream, if any.
         /// </summary>
         /// <remarks>
         /// <para>
         /// By default, any underlying stream is closed by this method. To configure this behaviour,
         /// use a constructor overload with a <c>leaveOpen</c> parameter. If this instance does not
         /// have an underlying stream, this method does nothing.
         /// </para>
         /// <para>
         /// For the sake of efficiency, calling this method does not prevent future write calls - but
         /// if a later write ends up writing to a stream which has been disposed, that is likely to
         /// fail. It is recommend that you not call any other methods after this.
         /// </para>
         /// </remarks>
         public void Dispose()
         {
             Flush();
             if (!leaveOpen)
             {
                 output.Dispose();
             }
         }

         /// <summary>
         /// Flushes any buffered data to the underlying stream (if there is one).
         /// </summary>
         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.");
                 }
             }
         }
     }
 }
	#region Copyright notice and license
	// Protocol Buffers - Google's data interchange format
	// Copyright 2008 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 Google.Protobuf.Collections;
	using System;
	using System.IO;
	using System.Text;

	namespace Google.Protobuf
	{
	/// <summary>
	/// Encodes and writes protocol message fields.
	/// </summary>
	/// <remarks>
	/// <para>
	/// This class is generally used by generated code to write appropriate
	/// primitives to the stream. It effectively encapsulates the lowest
	/// levels of protocol buffer format. Unlike some other implementations,
	/// this does not include combined "write tag and value" methods. Generated
	/// code knows the exact byte representations of the tags they're going to write,
	/// so there's no need to re-encode them each time. Manually-written code calling
	/// this class should just call one of the <c>WriteTag</c> overloads before each value.
	/// </para>
	/// <para>
	/// Repeated fields and map fields are not handled by this class; use <c>RepeatedField<T></c>
	/// and <c>MapField<TKey, TValue></c> to serialize such fields.
	/// </para>
	/// </remarks>
	public sealed partial class CodedOutputStream : IDisposable
	{
	// "Local" copy of Encoding.UTF8, for efficiency. (Yes, it makes a difference.)
	internal static readonly Encoding Utf8Encoding = Encoding.UTF8;

	/// <summary>
	/// The buffer size used by CreateInstance(Stream).
	/// </summary>
	public static readonly int DefaultBufferSize = 4096;

	private readonly bool leaveOpen;
	private readonly byte[] buffer;
	private readonly int limit;
	private int position;
	private readonly Stream output;

	#region Construction
	/// <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 CodedOutputStream(byte[] flatArray) : this(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>
	private CodedOutputStream(byte[] buffer, int offset, int length)
	{
	this.output = null;
	this.buffer = buffer;
	this.position = offset;
	this.limit = offset + length;
	leaveOpen = true; // Simple way of avoiding trying to dispose of a null reference
	}

	private CodedOutputStream(Stream output, byte[] buffer, bool leaveOpen)
	{
	this.output = ProtoPreconditions.CheckNotNull(output, nameof(output));
	this.buffer = buffer;
	this.position = 0;
	this.limit = buffer.Length;
	this.leaveOpen = leaveOpen;
	}

	/// <summary>
	/// Creates a new <see cref="CodedOutputStream" /> which write to the given stream, and disposes of that
	/// stream when the returned <c>CodedOutputStream</c> is disposed.
	/// </summary>
	/// <param name="output">The stream to write to. It will be disposed when the returned <c>CodedOutputStream is disposed.</c></param>
	public CodedOutputStream(Stream output) : this(output, DefaultBufferSize, false)
	{
	}

	/// <summary>
	/// Creates a new CodedOutputStream which write to the given stream and uses
	/// the specified buffer size.
	/// </summary>
	/// <param name="output">The stream to write to. It will be disposed when the returned <c>CodedOutputStream is disposed.</c></param>
	/// <param name="bufferSize">The size of buffer to use internally.</param>
	public CodedOutputStream(Stream output, int bufferSize) : this(output, new byte[bufferSize], false)
	{
	}

	/// <summary>
	/// Creates a new CodedOutputStream which write to the given stream.
	/// </summary>
	/// <param name="output">The stream to write to.</param>
	/// <param name="leaveOpen">If <c>true</c>, <paramref name="output"/> is left open when the returned <c>CodedOutputStream</c> is disposed;
	/// if <c>false</c>, the provided stream is disposed as well.</param>
	public CodedOutputStream(Stream output, bool leaveOpen) : this(output, DefaultBufferSize, leaveOpen)
	{
	}

	/// <summary>
	/// Creates a new CodedOutputStream which write to the given stream and uses
	/// the specified buffer size.
	/// </summary>
	/// <param name="output">The stream to write to.</param>
	/// <param name="bufferSize">The size of buffer to use internally.</param>
	/// <param name="leaveOpen">If <c>true</c>, <paramref name="output"/> is left open when the returned <c>CodedOutputStream</c> is disposed;
	/// if <c>false</c>, the provided stream is disposed as well.</param>
	public CodedOutputStream(Stream output, int bufferSize, bool leaveOpen) : this(output, new byte[bufferSize], leaveOpen)
	{
	}
	#endregion

	/// <summary>
	/// Returns the current position in the stream, or the position in the output buffer
	/// </summary>
	public long Position
	{
	get
	{
	if (output != null)
	{
	return output.Position + position;
	}
	return position;
	}
	}

	#region Writing of values (not including tags)

	/// <summary>
	/// 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));
	}

	/// <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);
	if (!BitConverter.IsLittleEndian)
	{
	ByteArray.Reverse(rawBytes);
	}

	if (limit - position >= 4)
	{
	buffer[position++] = rawBytes[0];
	buffer[position++] = rawBytes[1];
	buffer[position++] = rawBytes[2];
	buffer[position++] = rawBytes[3];
	}
	else
	{
	WriteRawBytes(rawBytes, 0, 4);
	}
	}

	/// <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);
	}

	/// <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);
	}

	/// <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)
	{
	WriteRawVarint32((uint) value);
	}
	else
	{
	// Must sign-extend.
	WriteRawVarint64((ulong) value);
	}
	}

	/// <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);
	}

	/// <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);
	}

	/// <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);
	}

	/// <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);
	WriteLength(length);
	if (limit - position >= length)
	{
	if (length == value.Length) // Must be all ASCII...
	{
	for (int i = 0; i < length; i++)
	{
	buffer[position + i] = (byte)value[i];
	}
	}
	else
	{
	Utf8Encoding.GetBytes(value, 0, value.Length, buffer, position);
	}
	position += length;
	}
	else
	{
	byte[] bytes = Utf8Encoding.GetBytes(value);
	WriteRawBytes(bytes);
	}
	}

	/// <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)
	{
	WriteLength(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)
	{
	WriteLength(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);
	}

	/// <summary>
	/// Writes an sfixed32 value, without a tag, to the stream.
	/// </summary>
	/// <param name="value">The value to write.</param>
	public void WriteSFixed32(int value)
	{
	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));
	}

	/// <summary>
	/// Writes an already-encoded tag.
	/// </summary>
	/// <param name="tag">The encoded tag</param>
	public void WriteTag(uint tag)
	{
	WriteRawVarint32(tag);
	}

	/// <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);
	}

	/// <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);
	WriteRawByte(b2);
	}

	/// <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);
	WriteRawByte(b2);
	WriteRawByte(b3);
	}

	/// <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);
	WriteRawByte(b2);
	WriteRawByte(b3);
	WriteRawByte(b4);
	}

	/// <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);
	WriteRawByte(b2);
	WriteRawByte(b3);
	WriteRawByte(b4);
	WriteRawByte(b5);
	}
	#endregion

	#region Underlying writing primitives
	/// <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>
	internal void WriteRawVarint32(uint value)
	{
	// Optimize for the common case of a single byte value
	if (value < 128 && position < limit)
	{
	buffer[position++] = (byte)value;
	return;
	}

	while (value > 127 && position < limit)
	{
	buffer[position++] = (byte) ((value & 0x7F) \| 0x80);
	value >>= 7;
	}
	while (value > 127)
	{
	WriteRawByte((byte) ((value & 0x7F) \| 0x80));
	value >>= 7;
	}
	if (position < limit)
	{
	buffer[position++] = (byte) value;
	}
	else
	{
	WriteRawByte((byte) value);
	}
	}

	internal void WriteRawVarint64(ulong value)
	{
	while (value > 127 && position < limit)
	{
	buffer[position++] = (byte) ((value & 0x7F) \| 0x80);
	value >>= 7;
	}
	while (value > 127)
	{
	WriteRawByte((byte) ((value & 0x7F) \| 0x80));
	value >>= 7;
	}
	if (position < limit)
	{
	buffer[position++] = (byte) value;
	}
	else
	{
	WriteRawByte((byte) value);
	}
	}

	internal void WriteRawLittleEndian32(uint value)
	{
	if (position + 4 > limit)
	{
	WriteRawByte((byte) value);
	WriteRawByte((byte) (value >> 8));
	WriteRawByte((byte) (value >> 16));
	WriteRawByte((byte) (value >> 24));
	}
	else
	{
	buffer[position++] = ((byte) value);
	buffer[position++] = ((byte) (value >> 8));
	buffer[position++] = ((byte) (value >> 16));
	buffer[position++] = ((byte) (value >> 24));
	}
	}

	internal void WriteRawLittleEndian64(ulong value)
	{
	if (position + 8 > limit)
	{
	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));
	}
	else
	{
	buffer[position++] = ((byte) value);
	buffer[position++] = ((byte) (value >> 8));
	buffer[position++] = ((byte) (value >> 16));
	buffer[position++] = ((byte) (value >> 24));
	buffer[position++] = ((byte) (value >> 32));
	buffer[position++] = ((byte) (value >> 40));
	buffer[position++] = ((byte) (value >> 48));
	buffer[position++] = ((byte) (value >> 56));
	}
	}

	internal void WriteRawByte(byte value)
	{
	if (position == limit)
	{
	RefreshBuffer();
	}

	buffer[position++] = value;
	}

	internal void WriteRawByte(uint value)
	{
	WriteRawByte((byte) value);
	}

	/// <summary>
	/// Writes out an array of bytes.
	/// </summary>
	internal void WriteRawBytes(byte[] value)
	{
	WriteRawBytes(value, 0, value.Length);
	}

	/// <summary>
	/// Writes out part of an array of bytes.
	/// </summary>
	internal void WriteRawBytes(byte[] value, int offset, int length)
	{
	if (limit - position >= length)
	{
	ByteArray.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;
	ByteArray.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.
	ByteArray.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

	/// <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>
	internal 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>
	internal 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.")
	{
	}
	}

	/// <summary>
	/// Flushes any buffered data and optionally closes the underlying stream, if any.
	/// </summary>
	/// <remarks>
	/// <para>
	/// By default, any underlying stream is closed by this method. To configure this behaviour,
	/// use a constructor overload with a <c>leaveOpen</c> parameter. If this instance does not
	/// have an underlying stream, this method does nothing.
	/// </para>
	/// <para>
	/// For the sake of efficiency, calling this method does not prevent future write calls - but
	/// if a later write ends up writing to a stream which has been disposed, that is likely to
	/// fail. It is recommend that you not call any other methods after this.
	/// </para>
	/// </remarks>
	public void Dispose()
	{
	Flush();
	if (!leaveOpen)
	{
	output.Dispose();
	}
	}

	/// <summary>
	/// Flushes any buffered data to the underlying stream (if there is one).
	/// </summary>
	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.");
	}
	}
	}
	}
	}