Package blbutil

Class BitList

java.lang.Object

blbutil.BitList

public class BitList
extends java.lang.Object

Interface BitList represents a mutable sequence of bits with a fixed length.

Instances of BitList are not thread-safe.

Constructor Summary

Constructors

Constructor	Description
BitList(int size)	Constructs a BitList instance with the specified size and having all bits set to 0 (unset).
BitList(long[] values, int size)	Constructs a BitList instance from the specified values.
BitList(BitList bitList)	Constructs a new BitList instance with the same sequence of bits and the same size as the specified BitList.

Method Summary

Modifier and Type	Method	Description
void	clear()	Clears all bits.
void	clear(int index)	Clears the specified bit.
void	copyFrom(BitList src, int from, int to)	Replaced the specified bits in this Bitlist with the corresponding bits in the specified BitList.
boolean	equal(BitList other, int from, int to)	Returns true if this Bitlist and the specified BitList have identical sequences of bits for the specified indices, and returns false otherwise.
static boolean	equals(BitList a, BitList b)	Returns true if the specified BitList objects represent identical bit sequences having the same size, and returns false otherwise.
boolean	get(int index)	Returns the specified bit as a boolean value.
int	getAsInt(int index)	Returns the specified bit as a int value.
int	hash(int from, int to)	Returns a hash code for the specified bits in this Bitlist
BitList	restrict(int from, int to)	Returns a new BitList of size (from - to) that is a copy of the specified bit indices of this BitList.
void	set(int index)	Sets the specified bit.
int	size()	Returns the number of bits in this BitList.
static void	swapBits(BitList a, BitList b, int from, int to)	Swaps the specified bits of the two specified Bitlist objects.
long[]	toLongArray()	Returns this BitList as a long array.
java.lang.String	toString()	Returns a string representation of this BitList.

Methods inherited from class java.lang.Object

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

Constructor Detail

BitList

public BitList(int size)

Constructs a BitList instance with the specified size and having all bits set to 0 (unset).

Parameters:

size - the number of bits

Throws:

java.lang.IllegalArgumentException - if size < 0

BitList

public BitList(long[] values,
               int size)

Constructs a BitList instance from the specified values.

Parameters:

values - a sequence of bits

size - the number of bits

Throws:

java.lang.IllegalArgumentException - if size < 0

java.lang.IllegalArgumentException - if values.length != (size + Long.SIZE - 1) / Long.SIZE

java.lang.NullPointerException - if values == null

BitList

public BitList(BitList bitList)

Constructs a new BitList instance with the same sequence of bits and the same size as the specified BitList.

Parameters:

bitList - a sequence of bits to be copied

Throws:

java.lang.NullPointerException - if bitList == null

Method Detail

size

public int size()

Returns the number of bits in this BitList.

Returns:

the number of bits in this BitList

get

public boolean get(int index)

Returns the specified bit as a boolean value. A 1 bit returns true and a 0 bit returns false.

Parameters:

index - a bit index

Returns:

the specified bit as a boolean value.

Throws:

java.lang.IndexOutOfBoundsException - if index < 0 || index >= this.size()

getAsInt

public int getAsInt(int index)

Returns the specified bit as a int value.

Parameters:

index - a bit index

Returns:

the specified bit as a int value.

Throws:

java.lang.IndexOutOfBoundsException - if index < 0 || index >= this.size()

set

public void set(int index)

Sets the specified bit.

Parameters:

index - a bit index

Throws:

java.lang.IndexOutOfBoundsException - if index < 0 || index >= this.size()

clear

public void clear(int index)

Clears the specified bit.

Parameters:

index - a bit index

Throws:

java.lang.IndexOutOfBoundsException - if index < 0 || index >= this.size()

clear

public void clear()

Clears all bits.

restrict

public BitList restrict(int from,
                        int to)

Returns a new BitList of size (from - to) that is a copy of the specified bit indices of this BitList.

Parameters:

from - the first bit to be copied (inclusive)

to - the last bit to be copied (exclusive)

Returns:

a new BitList of size (from - to) that is a copy of the specified bit indices of this BitList

Throws:

java.lang.IndexOutOfBoundsException - if from < 0 || from > to || to > this.size

copyFrom

public void copyFrom(BitList src,
                     int from,
                     int to)

Replaced the specified bits in this Bitlist with the corresponding bits in the specified BitList.

Parameters:

src - the BitList to be copied from

from - the first bit to be copied (inclusive)

to - the last bit to be copied (exclusive)

Throws:

java.lang.IndexOutOfBoundsException - if from < 0 || from > to || to > this.size || to > src.size()

java.lang.NullPointerException - if src == null

hash

public int hash(int from,
                int to)

Returns a hash code for the specified bits in this Bitlist

Parameters:

from - the first bit (inclusive)

to - the last bit (exclusive)

Returns:

a hash code for the specified bits in this Bitlist

Throws:

java.lang.IndexOutOfBoundsException - if from < 0 || from > to || to > this.size

swapBits

public static void swapBits(BitList a,
                            BitList b,
                            int from,
                            int to)

Swaps the specified bits of the two specified Bitlist objects.

Parameters:

a - the first BitList

b - the second BitList

from - the first bit to be copied (inclusive)

to - the last bit to be copied (exclusive)

Throws:

java.lang.IllegalArgumentException - if s.size() != b.size()

java.lang.IndexOutOfBoundsException - if from < 0 || from > to || to > a.size()

java.lang.NullPointerException - if a == null || b == null

equal

public boolean equal(BitList other,
                     int from,
                     int to)

Returns true if this Bitlist and the specified BitList have identical sequences of bits for the specified indices, and returns false otherwise.

Parameters:

other - the BitList to be compared with this for equality.

from - the first bit to be compared (inclusive)

to - the last bit to be compared (exclusive)

Returns:

true if this Bitlist and the specified BitList have identical sequences of bits for the specified indices.

Throws:

java.lang.IndexOutOfBoundsException - if from < 0 || from > to || to > this.size || to > other.size()

java.lang.NullPointerException - if other == null

toLongArray

public long[] toLongArray()

Returns this BitList as a long array.

Returns:

this BitList as a long array

toString

public java.lang.String toString()

Returns a string representation of this BitList. The exact details of the representation are unspecified and subject to change.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this BitList.

equals

public static boolean equals(BitList a,
                             BitList b)

Returns true if the specified BitList objects represent identical bit sequences having the same size, and returns false otherwise.

Parameters:

a - a sequence of long values

b - a sequence of long values

Returns:

true if the specified BitList objects represent identical bit sequences having the same size

Throws:

java.lang.NullPointerException - if a == null || b == null