io.lacuna.bifurcan.utils

Class Bits

java.lang.Object

io.lacuna.bifurcan.utils.Bits

public class Bits
extends Object

Constructor Summary

Constructors

Constructor and Description
Bits()

Method Summary

Modifier and Type	Method and Description
static int	bitOffset(long n)
static int	branchingBit(long a, long b)
static int	highestBit(int n)
static long	highestBit(long n)
static boolean	isPowerOfTwo(long n)
static int	log2Ceil(long n)
static int	log2Floor(long n)
static int	lowestBit(int n)
static long	lowestBit(long n)
static long	maskAbove(int bits)
static long	maskBelow(int bits)
static long	slice(long n, int start, int end)
static boolean	test(int n, int offset)
static boolean	test(long n, int offset)

Methods inherited from class java.lang.Object

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

Constructor Detail

Bits

public Bits()

Method Detail

bitOffset

public static int bitOffset(long n)

Parameters:

n - a number, which must be a power of two

Returns:

the offset of the bit

lowestBit

public static long lowestBit(long n)

Parameters:

n - a number

Returns:

the same number, with all but the lowest bit zeroed out

lowestBit

public static int lowestBit(int n)

Parameters:

n - a number

Returns:

the same number, with all but the lowest bit zeroed out

highestBit

public static long highestBit(long n)

Parameters:

n - a number

Returns:

the same number, with all but the highest bit zeroed out

highestBit

public static int highestBit(int n)

Parameters:

n - a number

Returns:

the same number, with all but the highest bit zeroed out

log2Floor

public static int log2Floor(long n)

Parameters:

n - a number

Returns:

the log2 of that value, rounded down

log2Ceil

public static int log2Ceil(long n)

Parameters:

n - a number

Returns:

the log2 of the value, rounded up

test

public static boolean test(int n,
                           int offset)

Parameters:

n - a number

offset - the offset of the bit being tested

Returns:

true if the bit is 1, false otherwise

test

public static boolean test(long n,
                           int offset)

Parameters:

n - a number

offset - the offset of the bit being tested

Returns:

true if the bit is 1, false otherwise

maskBelow

public static long maskBelow(int bits)

Parameters:

bits - a bit offset

Returns:

a mask, with all bits below that offset set to one

maskAbove

public static long maskAbove(int bits)

Parameters:

bits - a bit offset

Returns:

a mask, with all bits above that offset set to one

branchingBit

public static int branchingBit(long a,
                               long b)

Returns:

the offset of the highest bit which differs between a and b

isPowerOfTwo

public static boolean isPowerOfTwo(long n)

Parameters:

n - a number

Returns:

true, if the number is a power of two

slice

public static long slice(long n,
                         int start,
                         int end)