ParsableBitArray

@UnstableApi
@CheckReturnValue
public final class ParsableBitArray

Wraps a byte array, providing methods that allow it to be read as a bitstream.

Summary

Public fields
byte[]

Public constructors

Creates a new instance that initially has no backing data.
ParsableBitArray(byte[] data)

Creates a new instance that wraps an existing array.
ParsableBitArray(byte[] data, int limit)

Creates a new instance that wraps an existing array.

Public methods
int

Returns the number of bits yet to be read.
void

Aligns the position to the next byte boundary.
int

Returns the current byte offset.
int

Returns the current bit offset.
void
putInt(int value, int numBits)

Overwrites numBits from this array using the numBits least significant bits from value.
boolean

Reads a single bit.
int
readBits(int numBits)

Reads up to 32 bits.
void
readBits(byte[] buffer, int offset, int numBits)

Reads numBits bits into buffer.
long
readBitsToLong(int numBits)

Reads up to 64 bits.
void
readBytes(byte[] buffer, int offset, int length)

Reads the next length bytes into buffer.
String
readBytesAsString(int length)

Reads the next length bytes as a UTF-8 string.
String
readBytesAsString(int length, Charset charset)

Reads the next length bytes as a string encoded in Charset.
void
reset(byte[] data)

Updates the instance to wrap data, and resets the position to zero.
void
reset(ParsableByteArray parsableByteArray)

Sets this instance's data, position and limit to match the provided parsableByteArray.
void
reset(byte[] data, int limit)

Updates the instance to wrap data, and resets the position to zero.
void
setPosition(int position)

Sets the current bit offset.
void

Skips a single bit.
void
skipBits(int numBits)

Skips bits and moves current reading position forward.
void
skipBytes(int length)

Skips the next length bytes.

Public fields

data

public byte[] data

Public constructors

ParsableBitArray

public ParsableBitArray()

Creates a new instance that initially has no backing data.

ParsableBitArray

public ParsableBitArray(byte[] data)

Creates a new instance that wraps an existing array.

Parameters
byte[] data

The data to wrap.

ParsableBitArray

public ParsableBitArray(byte[] data, int limit)

Creates a new instance that wraps an existing array.

Parameters
byte[] data

The data to wrap.
int limit

The limit in bytes.

Public methods

bitsLeft

public int bitsLeft()

Returns the number of bits yet to be read.

byteAlign

public void byteAlign()

Aligns the position to the next byte boundary. Does nothing if the position is already aligned.

getBytePosition

public int getBytePosition()

Returns the current byte offset. Must only be called when the position is byte aligned.

Throws
java.lang.IllegalStateException

If the position isn't byte aligned.

getPosition

public int getPosition()

Returns the current bit offset.

putInt

public void putInt(int value, int numBits)

Overwrites numBits from this array using the numBits least significant bits from value. Bits are written in order from most significant to least significant. The read position is advanced by numBits.

Parameters
int value

The integer whose numBits least significant bits are written into data.
int numBits

The number of bits to write.

readBit

public boolean readBit()

Reads a single bit.

Returns
boolean

Whether the bit is set.

readBits

public int readBits(int numBits)

Reads up to 32 bits.

Parameters
int numBits

The number of bits to read.
Returns
int

An integer whose bottom numBits bits hold the read data.

readBits

public void readBits(byte[] buffer, int offset, int numBits)

Reads numBits bits into buffer.

Parameters
byte[] buffer

The array into which the read data should be written. The trailing numBits % 8 bits are written into the most significant bits of the last modified buffer byte. The remaining ones are unmodified.
int offset

The offset in buffer at which the read data should be written.
int numBits

The number of bits to read.

readBitsToLong

public long readBitsToLong(int numBits)

Reads up to 64 bits.

Parameters
int numBits

The number of bits to read.
Returns
long

A long whose bottom numBits bits hold the read data.

readBytes

public void readBytes(byte[] buffer, int offset, int length)

Reads the next length bytes into buffer. Must only be called when the position is byte aligned.

Parameters
byte[] buffer

The array into which the read data should be written.
int offset

The offset in buffer at which the read data should be written.
int length

The number of bytes to read.
Throws
java.lang.IllegalStateException

If the position isn't byte aligned.
See also
arraycopy

readBytesAsString

public String readBytesAsString(int length)

Reads the next length bytes as a UTF-8 string. Must only be called when the position is byte aligned.

Parameters
int length

The number of bytes to read.
Returns
String

The string encoded by the bytes in UTF-8.

readBytesAsString

public String readBytesAsString(int length, Charset charset)

Reads the next length bytes as a string encoded in Charset. Must only be called when the position is byte aligned.

Parameters
int length

The number of bytes to read.
Charset charset

The character set of the encoded characters.
Returns
String

The string encoded by the bytes in the specified character set.

reset

public void reset(byte[] data)

Updates the instance to wrap data, and resets the position to zero.

Parameters
byte[] data

The array to wrap.

reset

public void reset(ParsableByteArray parsableByteArray)

Sets this instance's data, position and limit to match the provided parsableByteArray. Any modifications to the underlying data array will be visible in both instances

Parameters
ParsableByteArray parsableByteArray

The ParsableByteArray.

reset

public void reset(byte[] data, int limit)

Updates the instance to wrap data, and resets the position to zero.

Parameters
byte[] data

The array to wrap.
int limit

The limit in bytes.

setPosition

public void setPosition(int position)

Sets the current bit offset.

Parameters
int position

The position to set.

skipBit

public void skipBit()

Skips a single bit.

skipBits

public void skipBits(int numBits)

Skips bits and moves current reading position forward.

Parameters
int numBits

The number of bits to skip.

skipBytes

public void skipBytes(int length)

Skips the next length bytes. Must only be called when the position is byte aligned.

Parameters
int length

The number of bytes to read.
Throws
java.lang.IllegalStateException

If the position isn't byte aligned.