Struct DataStreamWriter

Data streams can be used to serialize data over the network. The DataStreamWriter and DataStreamReader classes work together to serialize data for sending and then to deserialize when receiving.

Namespace: Unity.Networking.Transport
Syntax
public struct DataStreamWriter : IDisposable
Remarks

The reader can be used to deserialize the data from a writer, writing data to a writer and reading it back can be done like this:

using (var dataWriter = new DataStreamWriter(16, Allocator.Persistent))
{
    dataWriter.Write(42);
    dataWriter.Write(1234);
    // Length is the actual amount of data inside the writer,
    // Capacity is the total amount.
    var dataReader = new DataStreamReader(dataWriter, 0, dataWriter.Length);
    var context = default(DataStreamReader.Context);
    var myFirstInt = dataReader.ReadInt(ref context);
    var mySecondInt = dataReader.ReadInt(ref context);
}

The writer needs to be Disposed (here done by wrapping usage in using statement) because it uses native memory which needs to be freed.

There are a number of functions for various data types. Each write call returns a Deferred* variant for that particular type and this can be used as a marker to overwrite the data later on, this is particularly useful when the size of the data is written at the start and you want to write it at the end when you know the value.

using (var data = new DataStreamWriter(16, Allocator.Persistent))
{
    // My header data
    var headerSizeMark = data.Write((ushort)0);
    var payloadSizeMark = data.Write((ushort)0);
    data.Write(42);
    data.Write(1234);
    var headerSize = data.Length;
    // Update header size to correct value
    headerSizeMark.Update((ushort)headerSize);
    // My payload data
    byte[] someBytes = Encoding.ASCII.GetBytes("some string");
    data.Write(someBytes, someBytes.Length);
    // Update payload size to correct value
    payloadSizeMark.Update((ushort)(data.Length - headerSize));
}

It's possible to get a more direct access to the buffer inside the reader/writer, in an unsafe way. See DataStreamUnsafeUtility

Constructors

DataStreamWriter(Int32, Allocator)

Declaration
public DataStreamWriter(int capacity, Allocator allocator)
Parameters
Type Name Description
Int32 capacity
Allocator allocator

Properties

Capacity

The total size of the data buffer, see Length for the size of space used in the buffer. Capacity can be changed after the writer has been created.

Declaration
public int Capacity { get; set; }
Property Value
Type Description
Int32
Exceptions
Type Condition
InvalidOperationException

Thrown if the given capacity is smaller than the current buffer usage.

IsCreated

True if there is a valid data buffer present. This would be false if the writer was created with no arguments.

Declaration
public bool IsCreated { get; }
Property Value
Type Description
Boolean

Length

The size of the buffer used. See Capacity for the total size.

Declaration
public int Length { get; }
Property Value
Type Description
Int32

LengthInBits

The size of the buffer used in bits. See Length for the length in bytes.

Declaration
public int LengthInBits { get; }
Property Value
Type Description
Int32

Methods

Clear()

Moves the write position to the start of the data buffer used.

Declaration
public void Clear()

CopyTo(Int32, Int32, NativeArray<Byte>)

Copy data from the writer to the given NativeArray, the data size (start to length) must not exceed the total size of the array or an exception will be thrown.

Declaration
public void CopyTo(int start, int length, NativeArray<byte> dest)
Parameters
Type Name Description
Int32 start
Int32 length
NativeArray<Byte> dest

CopyTo(Int32, Int32, ref Byte[])

Copy data from the writer to the given managed byte array, the data size (start to length) must not exceed the total size of the byte array or an exception will be thrown.

Declaration
public void CopyTo(int start, int length, ref byte[] dest)
Parameters
Type Name Description
Int32 start
Int32 length
Byte[] dest

Dispose()

The writer uses unmanaged memory for its data buffer. Dispose needs to be called to free this resource.

Declaration
public void Dispose()

Flush()

Declaration
public void Flush()

GetNativeSlice(Int32, Int32)

Create a NativeSlice with access to the raw data in the writer, the data size (start to length) must not exceed the total size of the array or an exception will be thrown.

Declaration
public NativeSlice<byte> GetNativeSlice(int start, int length)
Parameters
Type Name Description
Int32 start
Int32 length
Returns
Type Description
NativeSlice<Byte>

Write(Byte)

Declaration
public DataStreamWriter.DeferredByte Write(byte value)
Parameters
Type Name Description
Byte value
Returns
Type Description
DataStreamWriter.DeferredByte

Write(Byte[], Int32)

Copy byte array into the writers data buffer, up to the given length or the complete size if no length (or -1) is given.

Declaration
public void Write(byte[] value, int length = -1)
Parameters
Type Name Description
Byte[] value

Source byte array
Int32 length

Length to copy, omit this to copy all the byte array

Write(Int16)

Declaration
public DataStreamWriter.DeferredShort Write(short value)
Parameters
Type Name Description
Int16 value
Returns
Type Description
DataStreamWriter.DeferredShort

Write(Int32)

Declaration
public DataStreamWriter.DeferredInt Write(int value)
Parameters
Type Name Description
Int32 value
Returns
Type Description
DataStreamWriter.DeferredInt

Write(Single)

Declaration
public DataStreamWriter.DeferredFloat Write(float value)
Parameters
Type Name Description
Single value
Returns
Type Description
DataStreamWriter.DeferredFloat

Write(UInt16)

Declaration
public DataStreamWriter.DeferredUShort Write(ushort value)
Parameters
Type Name Description
UInt16 value
Returns
Type Description
DataStreamWriter.DeferredUShort

Write(UInt32)

Declaration
public DataStreamWriter.DeferredUInt Write(uint value)
Parameters
Type Name Description
UInt32 value
Returns
Type Description
DataStreamWriter.DeferredUInt

Write(UInt64)

Declaration
public void Write(ulong value)
Parameters
Type Name Description
UInt64 value

WriteBytes(Byte*, Int32)

Declaration
public void WriteBytes(byte *data, int bytes)
Parameters
Type Name Description
Byte* data
Int32 bytes

WriteNetworkByteOrder(Int16)

Declaration
public DataStreamWriter.DeferredShortNetworkByteOrder WriteNetworkByteOrder(short value)
Parameters
Type Name Description
Int16 value
Returns
Type Description
DataStreamWriter.DeferredShortNetworkByteOrder

WriteNetworkByteOrder(Int32)

Declaration
public DataStreamWriter.DeferredIntNetworkByteOrder WriteNetworkByteOrder(int value)
Parameters
Type Name Description
Int32 value
Returns
Type Description
DataStreamWriter.DeferredIntNetworkByteOrder

WriteNetworkByteOrder(UInt16)

Declaration
public DataStreamWriter.DeferredUShortNetworkByteOrder WriteNetworkByteOrder(ushort value)
Parameters
Type Name Description
UInt16 value
Returns
Type Description
DataStreamWriter.DeferredUShortNetworkByteOrder

WriteNetworkByteOrder(UInt32)

Declaration
public DataStreamWriter.DeferredUIntNetworkByteOrder WriteNetworkByteOrder(uint value)
Parameters
Type Name Description
UInt32 value
Returns
Type Description
DataStreamWriter.DeferredUIntNetworkByteOrder

WritePackedFloat(Single, NetworkCompressionModel)

Declaration
public void WritePackedFloat(float value, NetworkCompressionModel model)
Parameters
Type Name Description
Single value
NetworkCompressionModel model

WritePackedFloatDelta(Single, Single, NetworkCompressionModel)

Declaration
public void WritePackedFloatDelta(float value, float baseline, NetworkCompressionModel model)
Parameters
Type Name Description
Single value
Single baseline
NetworkCompressionModel model

WritePackedInt(Int32, NetworkCompressionModel)

Declaration
public void WritePackedInt(int value, NetworkCompressionModel model)
Parameters
Type Name Description
Int32 value
NetworkCompressionModel model

WritePackedIntDelta(Int32, Int32, NetworkCompressionModel)

Declaration
public void WritePackedIntDelta(int value, int baseline, NetworkCompressionModel model)
Parameters
Type Name Description
Int32 value
Int32 baseline
NetworkCompressionModel model

WritePackedStringDelta(NativeString64, NativeString64, NetworkCompressionModel)

Declaration
public void WritePackedStringDelta(NativeString64 str, NativeString64 baseline, NetworkCompressionModel model)
Parameters
Type Name Description
NativeString64 str
NativeString64 baseline
NetworkCompressionModel model

WritePackedUInt(UInt32, NetworkCompressionModel)

Declaration
public void WritePackedUInt(uint value, NetworkCompressionModel model)
Parameters
Type Name Description
UInt32 value
NetworkCompressionModel model

WritePackedUIntDelta(UInt32, UInt32, NetworkCompressionModel)

Declaration
public void WritePackedUIntDelta(uint value, uint baseline, NetworkCompressionModel model)
Parameters
Type Name Description
UInt32 value
UInt32 baseline
NetworkCompressionModel model

WriteString(NativeString64)

Declaration
public void WriteString(NativeString64 str)
Parameters
Type Name Description
NativeString64 str

Extension Methods