cc.redberry.core.utils

Class BitArray

java.lang.Object

cc.redberry.core.utils.BitArray

public class BitArray
extends java.lang.Object

This class represents an "array of booleans" with many fast and useful methods. Consumes ~ 8 times less memory than array of booleans for big sizes. Has slightly different semantics than java's built in BitSet and also provides additional functionality like loadValueFrom(BitArray, int, int, int) and copyOfRange(int, int).

Field Summary

Fields

Modifier and Type	Field and Description
static BitArray	EMPTY

Constructor Summary

Constructors

Constructor and Description
BitArray(boolean[] array) Creates a bit array from array of booleans
BitArray(int size) Creates an array with specified size.

Method Summary

Modifier and Type	Method and Description
void	and(BitArray bitArray) Compound assignment and.
BitArray	append(BitArray other)
int	bitCount() Returns the number of 1 bits.
void	clear(int i) Clears the specified bit (sets to 0)
void	clearAll() Clears all bits of this bit array
BitArray	clone() Returns a clone of this bit array.
BitArray	copyOfRange(int from)
BitArray	copyOfRange(int from, int to) Returns a new bit array, containing values from the specified range
boolean	equals(java.lang.Object o)
boolean	get(int i) Returns the state of specified bit
int[]	getBits() Returns an array with positions of all "1" bits.
int	hashCode()
boolean	intersects(BitArray bitArray) Returns true if there are 1 bits in the same positions.
boolean	isEmpty() Returns true if all bits in this array are in the 0 state.
boolean	isFull() Returns true if all bits in this array are in the 1 state.
void	loadValueFrom(BitArray bitArray) Copy values from the array of the same size
void	loadValueFrom(BitArray bitArray, int sourceOffset, int thisOffset, int length) Analog of System.arraycopy(Object, int, Object, int, int), where src is bitArray.
int	nextBit(int position) Returns the next "1" bit from the specified position.
int	nextZeroBit(int position) Returns the next "0" bit from the specified position (inclusively).
void	not() Inverts all bits in this bit array
void	or(BitArray bitArray) Compound assignment or.
void	set(int i) Sets the specified bit (sets to 1)
void	set(int i, boolean value) Sets the value of specified bit to specified value
void	setAll() Sets all bits of this bit array
void	setAll(int[] positions, boolean value) Sets values at specified positions to specified value
void	setAll(IntArrayList positions, boolean value) Sets values at specified positions to specified value
int	size() Returns the length of this bit array
BitArray	times(int times)
java.lang.String	toString()
void	xor(BitArray bitArray) Compound assignment xor.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY

public static final BitArray EMPTY

Constructor Detail

BitArray

public BitArray(int size)

Creates an array with specified size. Initial state of all bits is 0 (cleared).

Parameters:

size -

BitArray

public BitArray(boolean[] array)

Creates a bit array from array of booleans

Parameters:

array - boolean array

Method Detail

and

public void and(BitArray bitArray)

Compound assignment and.

Parameters:

bitArray - rhs of and

or

public void or(BitArray bitArray)

Compound assignment or.

Parameters:

bitArray - rhs of or

xor

public void xor(BitArray bitArray)

Compound assignment xor.

Parameters:

bitArray - rhs of xor

not

public void not()

Inverts all bits in this bit array

bitCount

public int bitCount()

Returns the number of 1 bits.

Returns:

number of 1 bits

clearAll

public void clearAll()

Clears all bits of this bit array

clone

public BitArray clone()

Returns a clone of this bit array.

Overrides:

clone in class java.lang.Object

Returns:

clone of this bit array

intersects

public boolean intersects(BitArray bitArray)

Returns true if there are 1 bits in the same positions. Equivalent to !this.and(other).isEmpty()

Parameters:

bitArray - other bit array

Returns:

true if there are 1 bits in the same positions

loadValueFrom

public void loadValueFrom(BitArray bitArray)

Copy values from the array of the same size

Parameters:

bitArray - bit array to copy values from

get

public boolean get(int i)

Returns the state of specified bit

Parameters:

i - index

Returns:

true if bit is set, false if bit is cleared

set

public void set(int i)

Sets the specified bit (sets to 1)

Parameters:

i - index of bit

clear

public void clear(int i)

Clears the specified bit (sets to 0)

Parameters:

i - index of bit

set

public void set(int i,
                boolean value)

Sets the value of specified bit to specified value

Parameters:

i - index

value - value

setAll

public void setAll(int[] positions,
                   boolean value)

Sets values at specified positions to specified value

Parameters:

positions - positions

value - value

setAll

public void setAll(IntArrayList positions,
                   boolean value)

Sets values at specified positions to specified value

Parameters:

positions - positions

value - value

setAll

public void setAll()

Sets all bits of this bit array

size

public int size()

Returns the length of this bit array

Returns:

length of this bit array

isFull

public boolean isFull()

Returns true if all bits in this array are in the 1 state.

Returns:

true if all bits in this array are in the 1 state

isEmpty

public boolean isEmpty()

Returns true if all bits in this array are in the 0 state.

Returns:

true if all bits in this array are in the 0 state

getBits

public int[] getBits()

Returns an array with positions of all "1" bits.

Returns:

array with positions of all "1" bits

nextBit

public int nextBit(int position)

Returns the next "1" bit from the specified position.

Parameters:

position - initial position

Returns:

position of the next "1" bit of -1 if all bits after position are 0

nextZeroBit

public int nextZeroBit(int position)

Returns the next "0" bit from the specified position (inclusively).

Parameters:

position - initial position

Returns:

position of the next "0" bit of -1 if all bits after position are 0

copyOfRange

public BitArray copyOfRange(int from,
                            int to)

Returns a new bit array, containing values from the specified range

Parameters:

from - lower bound of range

to - upper bound of range

Returns:

new bit array, containing values from the specified range

copyOfRange

public BitArray copyOfRange(int from)

loadValueFrom

public void loadValueFrom(BitArray bitArray,
                          int sourceOffset,
                          int thisOffset,
                          int length)

Analog of System.arraycopy(Object, int, Object, int, int), where src is bitArray.

Parameters:

bitArray - source

sourceOffset - source offset

thisOffset - destination offset

length - number of bits to copy

append

public BitArray append(BitArray other)

times

public BitArray times(int times)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object