Package org.basex.util

Class BitArray

java.lang.Object

org.basex.util.BitArray

public final class BitArray
extends Object

Bit array that grows when needed. The implementation is similar to BitSet.

Author:

BaseX Team 2005-23, BSD License, Dimitar Popov

Constructor Summary

Constructors

Constructor	Description
BitArray()	Constructs a new bit array.
BitArray(int capacity, boolean set)	Constructs a new bit array and an initial value.
BitArray(long[] array, int nr)	Constructs a new bit array with the specified backing array.

Method Summary

Modifier and Type	Method	Description
int	cardinality()	Returns the number of bits set to true.
void	clear(int i)	Sets the ith bit to 0.
boolean	get(int i)	Gets the value of the ith bit.
int	nextFree()	Gets the index of the first clear bit.
int	nextSet(int i)	Gets the next bit set to 1, starting from the ith bit.
void	set(int i)	Sets the ith bit to 1.
long[]	toArray()	The word array used to store the bits.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

BitArray

public BitArray(long[] array,
                int nr)

Constructs a new bit array with the specified backing array.

Parameters:

array - array with bits

nr - number of used bits

BitArray

public BitArray()

Constructs a new bit array.

BitArray

public BitArray(int capacity,
                boolean set)

Constructs a new bit array and an initial value.

Parameters:

capacity - initial number of bits

set - sets or clears all values

Method Detail

toArray

public long[] toArray()

The word array used to store the bits. The array is shrunk to the last word, where a bit is set.

Returns:

array of longs

cardinality

public int cardinality()

Returns the number of bits set to true.

Returns:

number of bits set to true

get

public boolean get(int i)

Gets the value of the i^th bit.

Parameters:

i - index of the bit

Returns:

true if the i^th bit is set

set

public void set(int i)

Sets the i^th bit to 1.

Parameters:

i - index of the bit

clear

public void clear(int i)

Sets the i^th bit to 0.

Parameters:

i - index of the bit

nextFree

public int nextFree()

Gets the index of the first clear bit.

Returns:

index

nextSet

public int nextSet(int i)

Gets the next bit set to 1, starting from the i^th bit.

Parameters:

i - index from which to start the search (inclusive)

Returns:

index of the next set bit after the i^th bit

toString

public String toString()

Overrides:

toString in class Object