BitString (JUtil documentation)

java.lang.Object
- net.cscott.jutil.BitString

All Implemented Interfaces:

Serializable, Cloneable
```
public final class BitString
extends Object
implements Cloneable, Serializable
```
BitString implements a vector of bits ; much like BitSet... except that this implementation actually works. Also, BitString has some groovy features which BitSet doesn't; mostly related to efficient iteration over true and false components, I think.
Each component of the BitString has a boolean value. The bits of a BitString are indexed by non-negative integers (that means they are zero-based, of course). Individual indexed bits can be examined, set, or cleared. One BitString may be used to modify the contents of another BitString through logical AND, logical inclusive OR, and logical exclusive OR operations.
By default, all bits in the set initially have the value false.
Every bit set has a current size, which is the number of bits of space currently in use by the bit set. Note that the size is related to the implementation of a bit set, so it may change with implementation. The length of a bit set related to the logical length of a bit set and is defined independently of implementation.

Version:

$Id: BitString.java,v 1.3 2006-10-30 19:58:05 cananian Exp $

Author:

John Whaley

See Also:
Serialized Form

Constructor Summary

Constructors
Constructor and Description

BitString(int nbits)
Creates an empty string with the specified size.

Constructors
Constructor and Description
`BitString(int nbits)` Creates an empty string with the specified size.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`and(BitString set)` Logically ANDs this bit set with the specified set of bits.
`void`	`clear(int bit)` Clears a bit.
`void`	`clearAll()` Clears all bits.
`void`	`clearUpTo(int bit)` Clears all bits up to and including the given bit.
`BitString`	`clone()` Clones the BitString.
`void`	`copyBits(BitString set)` Copies the values of the bits in the specified set into this set.
`boolean`	`equals(Object obj)` Compares this object against the specified object.
`int`	`firstSet()` Returns the first index in the bit string which is set, or -1 if there is no such index.
`int`	`firstSet(int where)` Returns the first index greater than `where` in the bit string which is set, or -1 if there is no such index.
`boolean`	`get(int bit)` Gets a bit.
`int`	`hashCode()` Returns a hash code value for this bit string whose value depends only on which bits have been set within this `BitString`.
`boolean`	`intersectionEmpty(BitString other)` Check if the intersection of the two sets is empty
`boolean`	`isZero()`
`int`	`lastSet()` Returns the last index in the bit string which is set, or -1 if there is no such index.
`int`	`lastSet(int where)` Returns the last index less than `where` in the bit string which is set, or -1 if there is no such index.
`int`	`length()` Returns the "logical size" of this `BitString`: the index of the highest set bit in the `BitString` plus one.
`static void`	`main(String[] argv)` Self-test function.
`int`	`numberOfOnes()`
`int`	`numberOfOnes(int where)`
`boolean`	`or_upTo(BitString set, int bit)` Logically ORs this bit set with the specified set of bits.
`boolean`	`or(BitString set)` Logically ORs this bit set with the specified set of bits.
`void`	`set(int bit)` Sets a bit.
`void`	`setAll()` Sets all bits.
`void`	`setUpTo(int bit)` Sets all bits up to and including the given bit.
`int`	`size()` Returns the number of bits of space actually in use by this `BitString` to represent bit values.
`String`	`toString()` Converts the BitString to a String.
`boolean`	`xor(BitString set)` Logically XORs this bit set with the specified set of bits.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - BitString
```
public BitString(int nbits)
```
    Creates an empty string with the specified size.
    
    Parameters:
    nbits - the size of the string
- Method Detail
  - firstSet
```
public int firstSet()
```
    Returns the first index in the bit string which is set, or -1 if there is no such index.
  - firstSet
```
public int firstSet(int where)
```
    Returns the first index greater than where in the bit string which is set, or -1 if there is no such index.
    
    Parameters:
    where - the starting point for the search. May be negative.
  - lastSet
```
public int lastSet(int where)
```
    Returns the last index less than where in the bit string which is set, or -1 if there is no such index.
    
    Parameters:
    where - the starting point for the search.
  - lastSet
```
public int lastSet()
```
    Returns the last index in the bit string which is set, or -1 if there is no such index.
  - setAll
```
public void setAll()
```
    Sets all bits.
  - setUpTo
```
public void setUpTo(int bit)
```
    Sets all bits up to and including the given bit.
    
    Parameters:
    bit - the bit to be set up to (zero-based)
  - set
```
public void set(int bit)
```
    Sets a bit.
    
    Parameters:
    bit - the bit to be set (zero-based)
  - clearAll
```
public void clearAll()
```
    Clears all bits.
  - clearUpTo
```
public void clearUpTo(int bit)
```
    Clears all bits up to and including the given bit.
    
    Parameters:
    bit - the bit to be set up to (zero-based)
  - clear
```
public void clear(int bit)
```
    Clears a bit.
    
    Parameters:
    bit - the bit to be cleared (zero-based)
  - get
```
public boolean get(int bit)
```
    Gets a bit.
    
    Parameters:
    bit - the bit to be gotten (zero-based)
  - and
```
public boolean and(BitString set)
```
    Logically ANDs this bit set with the specified set of bits. Returns true if this was modified in response to the operation.
    
    Parameters:
    set - the bit set to be ANDed with
  - or
```
public boolean or(BitString set)
```
    Logically ORs this bit set with the specified set of bits. Returns true if this was modified in response to the operation.
    
    Parameters:
    set - the bit set to be ORed with
  - or_upTo
```
public boolean or_upTo(BitString set,
              int bit)
```
    Logically ORs this bit set with the specified set of bits. Returns true if this was modified in response to the operation.
    
    Parameters:
    set - the bit set to be ORed with
  - xor
```
public boolean xor(BitString set)
```
    Logically XORs this bit set with the specified set of bits. Returns true if this was modified in response to the operation.
    
    Parameters:
    set - the bit set to be XORed with
  - intersectionEmpty
```
public boolean intersectionEmpty(BitString other)
```
    Check if the intersection of the two sets is empty
    
    Parameters:
    other - the set to check intersection with
  - copyBits
```
public void copyBits(BitString set)
```
    Copies the values of the bits in the specified set into this set.
    
    Parameters:
    set - the bit set to copy the bits from
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for this bit string whose value depends only on which bits have been set within this BitString.
    
    Overrides:
    
    hashCode in class Object
  - length
```
public int length()
```
    Returns the "logical size" of this BitString: the index of the highest set bit in the BitString plus one. Returns zero if the BitString contains no set bits.
  - size
```
public int size()
```
    Returns the number of bits of space actually in use by this BitString to represent bit values. The maximum element in the set is the size - 1st element. The minimum element in the set is the zero'th element.
  - equals
```
public boolean equals(Object obj)
```
    Compares this object against the specified object.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    obj - the object to compare with
    
    Returns:
    true if the contents of the bitsets are the same; false otherwise.
  - isZero
```
public boolean isZero()
```
  - numberOfOnes
```
public int numberOfOnes()
```
  - numberOfOnes
```
public int numberOfOnes(int where)
```
  - clone
```
public BitString clone()
```
    Clones the BitString.
    
    Overrides:
    
    clone in class Object
  - toString
```
public String toString()
```
    Converts the BitString to a String.
    
    Overrides:
    
    toString in class Object
  - main
```
public static void main(String[] argv)
```
    Self-test function.

Class BitString

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BitString

Method Detail

firstSet

firstSet

lastSet

lastSet

setAll

setUpTo

set

clearAll

clearUpTo

clear

get

and

or

or_upTo

xor

intersectionEmpty

copyBits

hashCode

length

size

equals

isZero

numberOfOnes

numberOfOnes

clone

toString

main