Package net.tangly.commons.utilities

Class BitUtilities

java.lang.Object

net.tangly.commons.utilities.BitUtilities

public final class BitUtilities
extends Object

The bit utility class provides utility functions to manipulate bit streams as used on older communication protocols. The functions manipulate byte (8 bits), short (16 bits) and long (32 bits) bit streams and append them into the bit stream at location. Mirror functions support the extraction of bits from a bit stream.

Any legacy bit oriented communication protocols can efficiently be handled with the provided functions.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BYTE	Size of a byte in bits.
static final int	DWORD	Size of a double word in bits.
static final int	WORD	Size of a word in bits.

Method Summary

Modifier and Type	Method	Description
static int	appendBits(byte[] stream, byte data, int position, int length)	Writes length number of bits from data into the byte stream at the bit position.
static int	appendBits(byte[] stream, int data, int position, int length)	Writes length number of bits from data into the byte stream at the bit position.
static int	appendBits(byte[] stream, short data, int position, int length)	Writes length number of bits from data into the byte stream at the bit position.
static byte	extractBitsToByte(byte[] stream, int position, int length)	Extracts length number of bits from the byte stream at the bit position.
static int	extractBitsToInt(byte[] stream, int position, int length)	Extracts length number of bits from the byte stream starting at the bit position.
static short	extractBitsToShort(byte[] stream, int position, int length)	Extracts length number of bits from the byte stream at the bit position.
static String	toHex(byte[] stream)	Transforms the stream of byte into a human-readable sequence of hexadecimal values.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

BYTE

public static final int BYTE

Size of a byte in bits.

See Also:

• Constant Field Values

WORD

public static final int WORD

Size of a word in bits.

See Also:

• Constant Field Values

DWORD

public static final int DWORD

Size of a double word in bits.

See Also:

• Constant Field Values

Method Details

appendBits

public static int appendBits(byte[] stream,
 byte data,
 int position,
 int length)

Writes length number of bits from data into the byte stream at the bit position. The assumption is that bits are appended and the stream is initialized to 0.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

data - byte of data to be inserted into the bit stream

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..8]

Returns:

the position at the end of the written stream

extractBitsToByte

public static byte extractBitsToByte(byte[] stream,
 int position,
 int length)

Extracts length number of bits from the byte stream at the bit position.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..8]

Returns:

the extracted data from the byte stream

appendBits

public static int appendBits(byte[] stream,
 short data,
 int position,
 int length)

Writes length number of bits from data into the byte stream at the bit position. The assumption is that bits are appended and the stream is initialized to 0.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

data - word of data to be inserted into the bit stream

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..16]

Returns:

the position at the end of the written stream

extractBitsToShort

public static short extractBitsToShort(byte[] stream,
 int position,
 int length)

Extracts length number of bits from the byte stream at the bit position.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..16]

Returns:

the extracted data from the byte stream

appendBits

public static int appendBits(byte[] stream,
 int data,
 int position,
 int length)

Writes length number of bits from data into the byte stream at the bit position. The assumption is that bits are appended and the stream is initialized to 0.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

data - long word of data to be inserted into the bit stream

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..32]

Returns:

the position at the end of the written stream

extractBitsToInt

public static int extractBitsToInt(byte[] stream,
 int position,
 int length)

Extracts length number of bits from the byte stream starting at the bit position.

Parameters:

stream - stream of bits encoded as an array of bytes. The stream cannot be null

position - start index in bits in the stream, starting at 0

length - number of bits to insert into the stream. The format is constrained in [1..32]

Returns:

the extracted data from the byte stream

toHex

public static String toHex(byte[] stream)

Transforms the stream of byte into a human-readable sequence of hexadecimal values.

Parameters:

stream - the byte stream to transform. The stream must not be null

Returns:

the hexadecimal representation of the byte stream