Skip navigation links

com.tangosol.util
Class BitHelper

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper

Direct Known Subclasses:

ExternalizableHelper

public class BitHelper

extends Base

A collection of methods for bit-based operations.

Author:

cp 2006.01.10 starting from the MemberSet implementation

Constructor Summary

BitHelper()

Method Summary

static int	countBits(byte b) Count the number of bits set in the passed integral value.
static int	countBits(int n) Count the number of bits set in the passed integral value.
static int	countBits(long l) Count the number of bits set in the passed integral value.
static int	indexOfLSB(byte b) Determine the least significant bit of the passed integral value.
static int	indexOfLSB(int n) Determine the least significant bit of the passed integral value.
static int	indexOfLSB(long l) Determine the least significant bit of the passed integral value.
static int	indexOfMSB(byte b) Determine the most significant bit of the passed integral value.
static int	indexOfMSB(int n) Determine the most significant bit of the passed integral value.
static int	indexOfMSB(long l) Determine the most significant bit of the passed integral value.
static byte	rotateLeft(byte b, int cBits) Rotate the bits of the passed byte value to the left by the number of bits specified.
static int	rotateLeft(int n, int cBits) Rotate the bits of the passed int value to the left by the number of bits specified.
static long	rotateLeft(long n, int cBits) Rotate the bits of the passed long value to the left by the number of bits specified.
static byte	rotateRight(byte b, int cBits) Rotate the bits of the passed byte value to the right by the number of bits specified.
static int	rotateRight(int n, int cBits) Rotate the bits of the passed int value to the right by the number of bits specified.
static long	rotateRight(long n, int cBits) Rotate the bits of the passed long value to the right by the number of bits specified.
static java.lang.String	toBitString(byte b) Convert a byte to a String of ones and zeros.
static java.lang.String	toBitString(int n) Convert an int to a String of ones and zeros.
static java.lang.String	toBitString(long l) Convert a long to a String of ones and zeros.
static byte[]	toBytes(int l) Convert the specified int into a byte array containing a series of eight bytes in big-endian form (MSB first).
static void	toBytes(int n, byte[] ab, int of) Convert the specified int into a series of eight bytes, and write them to the specified byte-array in big-endian form (MSB first).
static byte[]	toBytes(long l) Convert the specified long into a byte array containing a series of eight bytes in big-endian form (MSB first).
static void	toBytes(long l, byte[] ab, int of) Convert the specified long into a series of eight bytes, and write them to the specified byte-array in big-endian form (MSB first).
static int	toInt(byte[] ab) Return the int represented by the sequence of eight bytes (in big-endian form) in the specified byte-array.
static int	toInt(byte[] ab, int of) Return the int represented by the sequence of eight bytes (in big-endian form) in the specified byte-array starting at the given offset.
static long	toLong(byte[] ab) Return the long represented by the sequence of eight bytes (in big-endian form) in the specified byte-array.
static long	toLong(byte[] ab, int of) Return the long represented by the sequence of eight bytes (in big-endian form) in the specified byte-array starting at the given offset.

Constructor Detail

BitHelper

public BitHelper()

Method Detail

rotateLeft

public static byte rotateLeft(byte b,
                              int cBits)

Rotate the bits of the passed byte value to the left by the number of bits specified.

Parameters:

b - a byte value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

rotateRight

public static byte rotateRight(byte b,
                               int cBits)

Rotate the bits of the passed byte value to the right by the number of bits specified.

Parameters:

b - a byte value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

rotateLeft

public static int rotateLeft(int n,
                             int cBits)

Rotate the bits of the passed int value to the left by the number of bits specified.

Parameters:

n - an int value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

rotateRight

public static int rotateRight(int n,
                              int cBits)

Rotate the bits of the passed int value to the right by the number of bits specified.

Parameters:

n - an int value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

rotateLeft

public static long rotateLeft(long n,
                              int cBits)

Rotate the bits of the passed long value to the left by the number of bits specified.

Parameters:

n - a long value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

rotateRight

public static long rotateRight(long n,
                               int cBits)

Rotate the bits of the passed long value to the right by the number of bits specified.

Parameters:

n - a long value

cBits - the number of bit rotations to perform

Returns:

the value with its bits rotated as indicated

Since:

Coherence 3.5

countBits

public static int countBits(byte b)

Count the number of bits set in the passed integral value.

Parameters:

b - a byte

Returns:

the number of bits set in the byte [0..8]

countBits

public static int countBits(int n)

Count the number of bits set in the passed integral value.

Parameters:

n - an int

Returns:

the number of bits set in the int [0..32]

countBits

public static int countBits(long l)

Count the number of bits set in the passed integral value.

Parameters:

l - a long

Returns:

the number of bits set in the long [0..64]

indexOfMSB

public static int indexOfMSB(byte b)

Determine the most significant bit of the passed integral value.

Parameters:

b - a byte

Returns:

-1 if no bits are set; otherwise, the bit position p of the most significant bit such that 1 << p is the most significant bit of b

indexOfMSB

public static int indexOfMSB(int n)

Determine the most significant bit of the passed integral value.

Parameters:

n - an int

Returns:

-1 if no bits are set; otherwise, the bit position p of the most significant bit such that 1 << p is the most significant bit of n

indexOfMSB

public static int indexOfMSB(long l)

Determine the most significant bit of the passed integral value.

Parameters:

l - a long

Returns:

-1 if no bits are set; otherwise, the bit position p of the most significant bit such that 1 << p is the most significant bit of l

indexOfLSB

public static int indexOfLSB(byte b)

Determine the least significant bit of the passed integral value.

Parameters:

b - a byte

Returns:

-1 if no bits are set; otherwise, the bit position p of the least significant bit such that 1 << p is the least significant bit of b

indexOfLSB

public static int indexOfLSB(int n)

Determine the least significant bit of the passed integral value.

Parameters:

n - an int

Returns:

-1 if no bits are set; otherwise, the bit position p of the least significant bit such that 1 << p is the least significant bit of n

indexOfLSB

public static int indexOfLSB(long l)

Determine the least significant bit of the passed integral value.

Parameters:

l - a long

Returns:

-1 if no bits are set; otherwise, the bit position p of the least significant bit such that 1 << p is the least significant bit of l

toBitString

public static java.lang.String toBitString(byte b)

Convert a byte to a String of ones and zeros.

Parameters:

b - a byte

Returns:

a String of ones and zeros representing the byte value

toBitString

public static java.lang.String toBitString(int n)

Convert an int to a String of ones and zeros.

Parameters:

n - an int

Returns:

a String of ones and zeros representing the int value

toBitString

public static java.lang.String toBitString(long l)

Convert a long to a String of ones and zeros.

Parameters:

l - a long

Returns:

a String of ones and zeros representing the long value

toBytes

public static void toBytes(int n,
                           byte[] ab,
                           int of)

Convert the specified int into a series of eight bytes, and write them to the specified byte-array in big-endian form (MSB first).

Parameters:

n - the int to convert to bytes

ab - the byte array to write into

of - the starting offset

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is shorter than of + 4

toBytes

public static byte[] toBytes(int l)

Convert the specified int into a byte array containing a series of eight bytes in big-endian form (MSB first).

Parameters:

l - the int to convert to bytes

Returns:

a byte[] representing the big-endian representation of the int

toBytes

public static void toBytes(long l,
                           byte[] ab,
                           int of)

Convert the specified long into a series of eight bytes, and write them to the specified byte-array in big-endian form (MSB first).

Parameters:

l - the long to convert to bytes

ab - the byte array to write into

of - the starting offset

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is shorter than of + 8

toBytes

public static byte[] toBytes(long l)

Convert the specified long into a byte array containing a series of eight bytes in big-endian form (MSB first).

Parameters:

l - the long to convert to bytes

Returns:

a byte[] representing the big-endian representation of the long

toInt

public static int toInt(byte[] ab,
                        int of)

Return the int represented by the sequence of eight bytes (in big-endian form) in the specified byte-array starting at the given offset.

Parameters:

ab - the byte-array

of - the offset

Returns:

the int represented by the sequence of bytes

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is less than of + 4

toInt

public static int toInt(byte[] ab)

Return the int represented by the sequence of eight bytes (in big-endian form) in the specified byte-array.

Parameters:

ab - the byte-array

Returns:

the int represented by the byte-array

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is less than 4

toLong

public static long toLong(byte[] ab,
                          int of)

Return the long represented by the sequence of eight bytes (in big-endian form) in the specified byte-array starting at the given offset.

Parameters:

ab - the byte-array

of - the offset

Returns:

the long represented by the sequence of bytes

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is less than of + 8

toLong

public static long toLong(byte[] ab)

Return the long represented by the sequence of eight bytes (in big-endian form) in the specified byte-array.

Parameters:

ab - the byte-array

Returns:

the long represented by the byte-array

Throws:

java.lang.ArrayIndexOutOfBoundsException - iff the length of the byte array is less than 8

Skip navigation links