org.jscsi.target.util

Class BitManip

java.lang.Object

org.jscsi.target.util.BitManip

public final class BitManip
extends Object

A utility class with static methods for accessing individual bits of bytes.

The value of a single bit can be easily retrieved with the getBit(byte, int) method.

Setting a bit is a little bit more complicated. The byte to be changed must be set to the return value of getByteWithBitSet(byte, int, boolean).

Author:

Andreas Ergenzinger

Constructor Summary

Constructors

Constructor and Description
BitManip()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	getBit(byte b, int bitNumber) Returns true, if the bit at the given position is set to one and false if it is set to zero .
static byte	getByteWithBitSet(byte b, int bitNumber, boolean value) Sets a single bit.

Methods inherited from class java.lang.Object

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

Constructor Detail

BitManip

public BitManip()

Method Detail

getByteWithBitSet

public static final byte getByteWithBitSet(byte b,
                     int bitNumber,
                     boolean value)

Sets a single bit. If the value parameter is true, the bit will be set to one, and to zero otherwise. All other bits will be left unchanged.

The bits are numbered in big-endian format, from 0 (LSB) to 7 (MSB).

+---+---+---+---+---+---+---+---+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | bit number
+---+---+---+---+---+---+---+---+


Parameters:

b - the original byte value

bitNumber - the big-endian position of the bit to be changed, from 0 to 7

value - true for 1, false for 0

Returns:

the edited byte value

getBit

public static boolean getBit(byte b,
             int bitNumber)

Returns true, if the bit at the given position is set to one and false if it is set to zero . The bits are numbered in big-endian format, from 0 (LSB) to 7 (MSB).

+---+---+---+---+---+---+---+---+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | bit number
+---+---+---+---+---+---+---+---+


Parameters:

b - the byte value in question

bitNumber - the big-endian position of the bit to be changed, from 0 to 7

Returns:

true if bit is set to one, else false