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(Span<byte>)

Read and copy data into the given Span of bytes. An error will be logged if not enough bytes are available to fill the array, and HasFailedReads will then be true.

Declaration
public void ReadBytes(Span<byte> span)
Parameters
Type Name Description
Span<byte> span

Span to copy data into.

ReadBytes(NativeArray<byte>)

Read and copy data into the given NativeArray of bytes. An error will be logged if not enough bytes are available to fill the array, and HasFailedReads will then be true.

Declaration
public void ReadBytes(NativeArray<byte> array)
Parameters
Type Name Description
NativeArray<byte> array

Array to copy data into.

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(in StreamCompressionModel)

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

Declaration
public double ReadPackedDouble(in 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, in 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, in 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, in StreamCompressionModel)

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

Declaration
public FixedString128Bytes ReadPackedFixedString128Delta(FixedString128Bytes baseline, in 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, in StreamCompressionModel)

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

Declaration
public FixedString32Bytes ReadPackedFixedString32Delta(FixedString32Bytes baseline, in 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, in StreamCompressionModel)

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

Declaration
public FixedString4096Bytes ReadPackedFixedString4096Delta(FixedString4096Bytes baseline, in 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, in StreamCompressionModel)

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

Declaration
public FixedString512Bytes ReadPackedFixedString512Delta(FixedString512Bytes baseline, in 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, in StreamCompressionModel)

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

Declaration
public FixedString64Bytes ReadPackedFixedString64Delta(FixedString64Bytes baseline, in 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>, in 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, in 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(in StreamCompressionModel)

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

Declaration
public float ReadPackedFloat(in 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, in 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, in 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(in 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(in 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, in StreamCompressionModel)

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

Declaration
public int ReadPackedIntDelta(int baseline, in 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(in 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(in 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, in StreamCompressionModel)

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

Declaration
public long ReadPackedLongDelta(long baseline, in 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(in 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(in 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, in StreamCompressionModel)

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

Declaration
public uint ReadPackedUIntDelta(uint baseline, in 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(in StreamCompressionModel)

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

Declaration
public ulong ReadPackedULong(in 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, in StreamCompressionModel)

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

Declaration
public ulong ReadPackedULongDelta(ulong baseline, in 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