Struct DataStreamReader

Writes data in an endian format to deserialize data.

Namespace: Unity.Collections

Assembly: Unity.Collections.dll

Syntax

[MovedFrom(true, "Unity.Networking.Transport", null, null)]
public struct DataStreamReader

Remarks

The DataStreamReader class is the counterpart of the DataStreamWriter class and can be be used to deserialize data which was prepared with it.

DataStreamWriter writes this data in the endian format native to the current machine architecture.
For network byte order use the so named methods.
Simple usage example:

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);
}

DataStreamReader carries the position of the read pointer inside the struct, taking a copy of the reader will also copy the read position. This includes passing the reader to a method by value instead of by ref.

DataStreamWriter IsLittleEndian

Constructors

DataStreamReader(NativeArray<byte>)

Initializes a new instance of the DataStreamReader struct with a NativeArray<byte>

Declaration

public DataStreamReader(NativeArray<byte> array)

Parameters

Type	Name	Description
NativeArray<byte>	array	The buffer to attach to the DataStreamReader.

Properties

HasFailedReads

If there is a read failure this returns true. A read failure might happen if this attempts to read more than there is capacity for.

Declaration

public readonly bool HasFailedReads { get; }

Property Value

Type	Description
bool

IsCreated

True if the reader has been pointed to a valid buffer space. This would be false if the reader was created with no arguments.

Declaration

public readonly bool IsCreated { get; }

Property Value

Type	Description
bool

IsLittleEndian

Show the byte order in which the current computer architecture stores data.

Declaration

public static bool IsLittleEndian { get; }

Property Value

Type	Description
bool

Remarks

Different computer architectures store data using different byte orders.

• Big-endian: the most significant byte is at the left end of a word.
• Little-endian: means the most significant byte is at the right end of a word.

Length

The total size of the buffer space this reader is working with.

Declaration

public readonly int Length { get; }

Property Value

Type	Description
int

Methods

GetBitsRead()

Gets the number of bits read from the data stream.

Declaration

public int GetBitsRead()

Returns

Type	Description
int	Number of bits read.

GetBytesRead()

Gets the number of bytes read from the data stream.

Declaration

public int GetBytesRead()

Returns

Type	Description
int	Number of bytes read.

ReadByte()

Reads an unsigned byte from the current stream and advances the current position of the stream by one byte.

Declaration

public byte ReadByte()

Returns

Type	Description
byte	The next byte read from the current stream, or 0 if the end of the stream has been reached.

ReadBytes(NativeArray<byte>)

Read and copy data into the given NativeArray of bytes, an error will be logged if not enough bytes are available.

Declaration

public void ReadBytes(NativeArray<byte> array)

Parameters

Type	Name	Description
NativeArray<byte>	array

ReadDouble()

Reads a 8-byte floating point value from the current stream and advances the current position of the stream by four bytes.

Declaration

public double ReadDouble()

Returns

Type	Description
double	A 8-byte floating point value read from the current stream, or 0 if the end of the stream has been reached.

ReadFixedString(NativeArray<byte>)

Read and copy data into the given NativeArray of bytes, an error will be logged if not enough bytes are available in the array.

Declaration

public ushort ReadFixedString(NativeArray<byte> array)

Parameters

Type	Name	Description
NativeArray<byte>	array	Buffer to write the string bytes to.

Returns

Type	Description
ushort	Length of data read into byte array, or zero if error occurred.

ReadFixedString128()

Reads a FixedString128Bytes value from the current stream and advances the current position of the stream by the length of the string.

Declaration

public FixedString128Bytes ReadFixedString128()

Returns

Type	Description
FixedString128Bytes	A FixedString128Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadFixedString32()

Reads a FixedString32Bytes value from the current stream and advances the current position of the stream by the length of the string.

Declaration

public FixedString32Bytes ReadFixedString32()

Returns

Type	Description
FixedString32Bytes	A FixedString32Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadFixedString4096()

Reads a FixedString4096Bytes value from the current stream and advances the current position of the stream by the length of the string.

Declaration

public FixedString4096Bytes ReadFixedString4096()

Returns

Type	Description
FixedString4096Bytes	A FixedString4096Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadFixedString512()

Reads a FixedString512Bytes value from the current stream and advances the current position of the stream by the length of the string.

Declaration

public FixedString512Bytes ReadFixedString512()

Returns

Type	Description
FixedString512Bytes	A FixedString512Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadFixedString64()

Reads a FixedString64Bytes value from the current stream and advances the current position of the stream by the length of the string.

Declaration

public FixedString64Bytes ReadFixedString64()

Returns

Type	Description
FixedString64Bytes	A FixedString64Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadFloat()

Reads a 4-byte floating point value from the current stream and advances the current position of the stream by four bytes.

Declaration

public float ReadFloat()

Returns

Type	Description
float	A 4-byte floating point value read from the current stream, or 0 if the end of the stream has been reached.

ReadInt()

Reads a 4-byte signed integer from the current stream and advances the current position of the stream by four bytes.

Declaration

public int ReadInt()

Returns

Type	Description
int	A 4-byte signed integer read from the current stream, or 0 if the end of the stream has been reached.

ReadIntNetworkByteOrder()

Reads a 4-byte signed integer from the current stream in Big-endian byte order and advances the current position of the stream by four bytes. If the current endianness is in little-endian order, the byte order will be swapped.

Declaration

public int ReadIntNetworkByteOrder()

Returns

Type	Description
int	A 4-byte signed integer read from the current stream, or 0 if the end of the stream has been reached.

ReadLong()

Reads an 8-byte signed long from the stream and advances the current position of the stream by eight bytes.

Declaration

public long ReadLong()

Returns

Type	Description
long	An 8-byte signed long read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedDouble(StreamCompressionModel)

Reads a 8-byte floating point value from the data stream using a StreamCompressionModel.

Declaration

public double ReadPackedDouble(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
double	A 8-byte floating point value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedDoubleDelta(double, StreamCompressionModel)

Reads a 8-byte floating point value from the data stream.

If the first bit is 0, the data did not change and baseline will be returned.

Declaration

public double ReadPackedDoubleDelta(double baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
double	baseline	The previous 8-byte floating point value.
StreamCompressionModel	model	Not currently used.

Returns

Type	Description
double	A 8-byte floating point value read from the current stream, or baseline if there are no changes to the value. See: HasFailedReads to verify if the read failed.

ReadPackedFixedString128Delta(FixedString128Bytes, StreamCompressionModel)

Reads a FixedString128Bytes delta value to the data stream using a StreamCompressionModel.

Declaration

public FixedString128Bytes ReadPackedFixedString128Delta(FixedString128Bytes baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
FixedString128Bytes	baseline	The previous FixedString128Bytes value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
FixedString128Bytes	A FixedString128Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFixedString32Delta(FixedString32Bytes, StreamCompressionModel)

Reads a FixedString32Bytes delta value to the data stream using a StreamCompressionModel.

Declaration

public FixedString32Bytes ReadPackedFixedString32Delta(FixedString32Bytes baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
FixedString32Bytes	baseline	The previous FixedString32Bytes value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
FixedString32Bytes	A FixedString32Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFixedString4096Delta(FixedString4096Bytes, StreamCompressionModel)

Reads a FixedString4096Bytes delta value to the data stream using a StreamCompressionModel.

Declaration

public FixedString4096Bytes ReadPackedFixedString4096Delta(FixedString4096Bytes baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
FixedString4096Bytes	baseline	The previous FixedString4096Bytes value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
FixedString4096Bytes	A FixedString4096Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFixedString512Delta(FixedString512Bytes, StreamCompressionModel)

Reads a FixedString512Bytes delta value to the data stream using a StreamCompressionModel.

Declaration

public FixedString512Bytes ReadPackedFixedString512Delta(FixedString512Bytes baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
FixedString512Bytes	baseline	The previous FixedString512Bytes value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
FixedString512Bytes	A FixedString512Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFixedString64Delta(FixedString64Bytes, StreamCompressionModel)

Reads a FixedString64Bytes delta value to the data stream using a StreamCompressionModel.

Declaration

public FixedString64Bytes ReadPackedFixedString64Delta(FixedString64Bytes baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
FixedString64Bytes	baseline	The previous FixedString64Bytes value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
FixedString64Bytes	A FixedString64Bytes value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFixedStringDelta(NativeArray<byte>, NativeArray<byte>, StreamCompressionModel)

Read and copy data into the given NativeArray of bytes, an error will be logged if not enough bytes are available in the array.

Declaration

public ushort ReadPackedFixedStringDelta(NativeArray<byte> data, NativeArray<byte> baseData, StreamCompressionModel model)

Parameters

Type	Name	Description
NativeArray<byte>	data	Array for the current fixed string.
NativeArray<byte>	baseData	Array containing the previous value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for writing value in a packed manner.

Returns

Type	Description
ushort	Length of data read into byte array, or zero if error occurred.

ReadPackedFloat(StreamCompressionModel)

Reads a 4-byte floating point value from the data stream using a StreamCompressionModel.

Declaration

public float ReadPackedFloat(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
float	A 4-byte floating point value read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedFloatDelta(float, StreamCompressionModel)

Reads a 4-byte floating point value from the data stream.

If the first bit is 0, the data did not change and baseline will be returned.

Declaration

public float ReadPackedFloatDelta(float baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
float	baseline	The previous 4-byte floating point value.
StreamCompressionModel	model	Not currently used.

Returns

Type	Description
float	A 4-byte floating point value read from the current stream, or baseline if there are no changes to the value. See: HasFailedReads to verify if the read failed.

ReadPackedInt(StreamCompressionModel)

Reads a 4-byte signed integer value from the data stream using a StreamCompressionModel.
Negative values de-interleaves from positive values before returning, for example (0, -1, 1, -2, 2) -> (-2, -1, 0, 1, 2)

Declaration

public int ReadPackedInt(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
int	A 4-byte signed integer read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedIntDelta(int, StreamCompressionModel)

Reads a 4-byte signed integer delta value from the data stream using a StreamCompressionModel.

Declaration

public int ReadPackedIntDelta(int baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
int	baseline	The previous 4-byte signed integer value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
int	A 4-byte signed integer read from the current stream, or 0 if the end of the stream has been reached. If the data did not change, this also returns 0. See: HasFailedReads to verify if the read failed.

ReadPackedLong(StreamCompressionModel)

Reads an 8-byte signed long value from the data stream using a StreamCompressionModel.
Negative values de-interleaves from positive values before returning, for example (0, -1, 1, -2, 2) -> (-2, -1, 0, 1, 2)

Declaration

public long ReadPackedLong(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
long	An 8-byte signed long read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedLongDelta(long, StreamCompressionModel)

Reads an 8-byte signed long delta value from the data stream using a StreamCompressionModel.

Declaration

public long ReadPackedLongDelta(long baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
long	baseline	The previous 8-byte signed long value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
long	An 8-byte signed long read from the current stream, or 0 if the end of the stream has been reached. If the data did not change, this also returns 0. See: HasFailedReads to verify if the read failed.

ReadPackedUInt(StreamCompressionModel)

Reads a 4-byte unsigned integer from the current stream using a StreamCompressionModel and advances the current position the number of bits depending on the model.

Declaration

public uint ReadPackedUInt(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
uint	A 4-byte unsigned integer read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedUIntDelta(uint, StreamCompressionModel)

Reads a 4-byte unsigned integer delta value from the data stream using a StreamCompressionModel.

Declaration

public uint ReadPackedUIntDelta(uint baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
uint	baseline	The previous 4-byte unsigned integer value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
uint	A 4-byte unsigned integer read from the current stream, or 0 if the end of the stream has been reached. If the data did not change, this also returns 0. See: HasFailedReads to verify if the read failed.

ReadPackedULong(StreamCompressionModel)

Reads an 8-byte unsigned long value from the data stream using a StreamCompressionModel.

Declaration

public ulong ReadPackedULong(StreamCompressionModel model)

Parameters

Type	Name	Description
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
ulong	An 8-byte unsigned long read from the current stream, or 0 if the end of the stream has been reached.

ReadPackedULongDelta(ulong, StreamCompressionModel)

Reads an 8-byte unsigned long delta value from the data stream using a StreamCompressionModel.

Declaration

public ulong ReadPackedULongDelta(ulong baseline, StreamCompressionModel model)

Parameters

Type	Name	Description
ulong	baseline	The previous 8-byte unsigned long value, used to compute the diff.
StreamCompressionModel	model	StreamCompressionModel model for reading value in a packed manner.

Returns

Type	Description
ulong	An 8-byte unsigned long read from the current stream, or 0 if the end of the stream has been reached. If the data did not change, this also returns 0. See: HasFailedReads to verify if the read failed.

ReadRawBits(int)

Reads a specified number of bits from the data stream.

Declaration

public uint ReadRawBits(int numbits)

Parameters

Type	Name	Description
int	numbits	A positive number of bytes to write.

Returns

Type	Description
uint	A 4-byte unsigned integer read from the current stream, or 0 if the end of the stream has been reached.

ReadShort()

Reads a 2-byte signed short from the current stream and advances the current position of the stream by two bytes.

Declaration

public short ReadShort()

Returns

Type	Description
short	A 2-byte signed short read from the current stream, or 0 if the end of the stream has been reached.

ReadShortNetworkByteOrder()

Reads a 2-byte signed short from the current stream in Big-endian byte order and advances the current position of the stream by two bytes. If the current endianness is in little-endian order, the byte order will be swapped.

Declaration

public short ReadShortNetworkByteOrder()

Returns

Type	Description
short	A 2-byte signed short read from the current stream, or 0 if the end of the stream has been reached.

ReadUInt()

Reads a 4-byte unsigned integer from the current stream and advances the current position of the stream by four bytes.

Declaration

public uint ReadUInt()

Returns

Type	Description
uint	A 4-byte unsigned integer read from the current stream, or 0 if the end of the stream has been reached.

ReadUIntNetworkByteOrder()

Reads a 4-byte unsigned integer from the current stream in Big-endian byte order and advances the current position of the stream by four bytes. If the current endianness is in little-endian order, the byte order will be swapped.

Declaration

public uint ReadUIntNetworkByteOrder()

Returns

Type	Description
uint	A 4-byte unsigned integer read from the current stream, or 0 if the end of the stream has been reached.

ReadULong()

Reads an 8-byte unsigned long from the stream and advances the current position of the stream by eight bytes.

Declaration

public ulong ReadULong()

Returns

Type	Description
ulong	An 8-byte unsigned long read from the current stream, or 0 if the end of the stream has been reached.

ReadUShort()

Reads a 2-byte unsigned short from the current stream and advances the current position of the stream by two bytes.

Declaration

public ushort ReadUShort()

Returns

Type	Description
ushort	A 2-byte unsigned short read from the current stream, or 0 if the end of the stream has been reached.

ReadUShortNetworkByteOrder()

Reads a 2-byte unsigned short from the current stream in Big-endian byte order and advances the current position of the stream by two bytes. If the current endianness is in little-endian order, the byte order will be swapped.

Declaration

public ushort ReadUShortNetworkByteOrder()

Returns

Type	Description
ushort	A 2-byte unsigned short read from the current stream, or 0 if the end of the stream has been reached.

SeekSet(int)

Sets the current position of this stream to the given value. An error will be logged if pos is outside the length of the stream.
In addition this will reset the bit index and the bit buffer.

Declaration

public void SeekSet(int pos)

Parameters

Type	Name	Description
int	pos	Seek position.

Extension Methods

DataStreamExtensions.ReadBytesUnsafe(ref DataStreamReader, byte*, int)

DataStreamExtensions.ReadFixedStringUnsafe(ref DataStreamReader, byte*, int)

DataStreamExtensions.ReadPackedFixedStringDeltaUnsafe(ref DataStreamReader, byte*, int, byte*, ushort, StreamCompressionModel)