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#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#endregion
using System;
using System.IO;
using System.Security;
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>
[SecuritySafeCritical]
public sealed partial class CodedOutputStream : IDisposable
{
/// <summary>
/// The buffer size used by CreateInstance(Stream).
/// </summary>
public static readonly int DefaultBufferSize = 4096;
private readonly bool leaveOpen;
private readonly byte[] buffer;
private WriterInternalState state;
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 = ProtoPreconditions.CheckNotNull(buffer, nameof(buffer));
this.state.position = offset;
this.state.limit = offset + length;
WriteBufferHelper.Initialize(this, out this.state.writeBufferHelper);
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.state.position = 0;
this.state.limit = buffer.Length;
WriteBufferHelper.Initialize(this, out this.state.writeBufferHelper);
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 + state.position;
}
return state.position;
}
}
/// <summary>
/// Configures whether or not serialization is deterministic.
/// </summary>
/// <remarks>
/// Deterministic serialization guarantees that for a given binary, equal messages (defined by the
/// equals methods in protos) will always be serialized to the same bytes. This implies:
/// <list type="bullet">
/// <item><description>Repeated serialization of a message will return the same bytes.</description></item>
/// <item><description>Different processes of the same binary (which may be executing on different machines)
/// will serialize equal messages to the same bytes.</description></item>
/// </list>
/// Note the deterministic serialization is NOT canonical across languages; it is also unstable
/// across different builds with schema changes due to unknown fields. Users who need canonical
/// serialization, e.g. persistent storage in a canonical form, fingerprinting, etc, should define
/// their own canonicalization specification and implement the serializer using reflection APIs
/// rather than relying on this API.
/// Once set, the serializer will: (Note this is an implementation detail and may subject to
/// change in the future)
/// <list type="bullet">
/// <item><description>Sort map entries by keys in lexicographical order or numerical order. Note: For string
/// keys, the order is based on comparing the UTF-16 code unit value of each character in the strings.
/// The order may be different from the deterministic serialization in other languages where
/// maps are sorted on the lexicographical order of the UTF8 encoded keys.</description></item>
/// </list>
/// </remarks>
public bool Deterministic { get; set; }
#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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteDouble(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteFloat(ref span, ref state, value);
}
/// <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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteUInt64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteInt64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteInt32(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteFixed64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteFixed32(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteBool(ref span, ref state, value);
}
/// <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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteString(ref span, ref state, value);
}
/// <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)
{
// TODO: if the message doesn't implement IBufferMessage (and thus does not provide the InternalWriteTo method),
// what we're doing here works fine, but could be more efficient.
// For now, this inefficiency is fine, considering this is only a backward-compatibility scenario (and regenerating the code fixes it).
var span = new Span<byte>(buffer);
WriteContext.Initialize(ref span, ref state, out WriteContext ctx);
try
{
WritingPrimitivesMessages.WriteMessage(ref ctx, value);
}
finally
{
ctx.CopyStateTo(this);
}
}
/// <summary>
/// Writes a message, without a tag, to the stream.
/// Only the message data is written, without a length-delimiter.
/// </summary>
/// <param name="value">The value to write</param>
public void WriteRawMessage(IMessage value)
{
// TODO: if the message doesn't implement IBufferMessage (and thus does not provide the InternalWriteTo method),
// what we're doing here works fine, but could be more efficient.
// For now, this inefficiency is fine, considering this is only a backward-compatibility scenario (and regenerating the code fixes it).
var span = new Span<byte>(buffer);
WriteContext.Initialize(ref span, ref state, out WriteContext ctx);
try
{
WritingPrimitivesMessages.WriteRawMessage(ref ctx, value);
}
finally
{
ctx.CopyStateTo(this);
}
}
/// <summary>
/// Writes a group, without a tag, to the stream.
/// </summary>
/// <param name="value">The value to write</param>
public void WriteGroup(IMessage value)
{
var span = new Span<byte>(buffer);
WriteContext.Initialize(ref span, ref state, out WriteContext ctx);
try
{
WritingPrimitivesMessages.WriteGroup(ref ctx, value);
}
finally
{
ctx.CopyStateTo(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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteBytes(ref span, ref state, value);
}
/// <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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteUInt32(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteEnum(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteSFixed32(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteSFixed64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteSInt32(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteSInt64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteLength(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteTag(ref span, ref state, fieldNumber, type);
}
/// <summary>
/// Writes an already-encoded tag.
/// </summary>
/// <param name="tag">The encoded tag</param>
public void WriteTag(uint tag)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteTag(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawTag(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawTag(ref span, ref state, b1, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawTag(ref span, ref state, b1, b2, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawTag(ref span, ref state, b1, b2, b3, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawTag(ref span, ref state, b1, b2, b3, b4, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawVarint32(ref span, ref state, value);
}
internal void WriteRawVarint64(ulong value)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawVarint64(ref span, ref state, value);
}
internal void WriteRawLittleEndian32(uint value)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawLittleEndian32(ref span, ref state, value);
}
internal void WriteRawLittleEndian64(ulong value)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawLittleEndian64(ref span, ref state, 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)
{
var span = new Span<byte>(buffer);
WritingPrimitives.WriteRawBytes(ref span, ref state, value, offset, length);
}
#endregion
/// <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()
{
var span = new Span<byte>(buffer);
WriteBufferHelper.Flush(ref span, ref state);
}
/// <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 finding bugs.
/// </summary>
public void CheckNoSpaceLeft()
{
WriteBufferHelper.CheckNoSpaceLeft(ref state);
}
/// <summary>
/// If writing to a flat array, returns the space left in the array. Otherwise,
/// throws an InvalidOperationException.
/// </summary>
public int SpaceLeft => WriteBufferHelper.GetSpaceLeft(ref state);
internal byte[] InternalBuffer => buffer;
internal Stream InternalOutputStream => output;
internal ref WriterInternalState InternalState => ref state;
}
}