com.googlecode.javaewah.datastructure
Class StaticBitSet

java.lang.Object
  com.googlecode.javaewah.datastructure.StaticBitSet

public class StaticBitSet
extends Object

This is an optimized version of Java's BitSet.

Since:

0.8.0

Author:

Daniel Lemire

Constructor Summary

StaticBitSet(int sizeinbits)
Construct a bitset with the specified number of bits (initially all false).

Method Summary

int	cardinality() Compute the number of bits set to 1
void	clear() Reset all bits to false
boolean	get(int i)
int	nextSetBit(int i) Usage: for(int i=bs.nextSetBit(0); i>=0; i=bs.nextSetBit(i+1)) { operate on index i here }
int	nextUnsetBit(int i) Usage: for(int i=bs.nextUnsetBit(0); i>=0; i=bs.nextUnsetBit(i+1)) { operate on index i here }
void	resize(int sizeinbits) Resize the bitset
void	set(int i) Set to true
void	set(int i, boolean b)
int	size() Query the size
void	unset(int i) Set to false

Methods inherited from class java.lang.Object

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

Constructor Detail

StaticBitSet

public StaticBitSet(int sizeinbits)

Construct a bitset with the specified number of bits (initially all false). The number of bits is rounded up to the nearest multiple of 64.

Parameters:

sizeinbits - the size in bits

Method Detail

size

public int size()

Query the size

Returns:

the size in bits.

resize

public void resize(int sizeinbits)

Resize the bitset

Parameters:

sizeinbits - new number of bits

clear

public void clear()

Reset all bits to false

cardinality

public int cardinality()

Compute the number of bits set to 1

Returns:

the number of bits

get

public boolean get(int i)

Parameters:

i - index

Returns:

value of the bit

set

public void set(int i)

Set to true

Parameters:

i - index of the bit

unset

public void unset(int i)

Set to false

Parameters:

i - index of the bit

set

public void set(int i,
                boolean b)

Parameters:

i - index

b - value of the bit

nextSetBit

public int nextSetBit(int i)

Usage: for(int i=bs.nextSetBit(0); i>=0; i=bs.nextSetBit(i+1)) { operate on index i here }

Parameters:

i - current set bit

Returns:

next set bit or -1

nextUnsetBit

public int nextUnsetBit(int i)

Usage: for(int i=bs.nextUnsetBit(0); i>=0; i=bs.nextUnsetBit(i+1)) { operate on index i here }

Parameters:

i - current unset bit

Returns:

next unset bit or -1