java.lang.Object
- com.github.javabdd.BitString

All Implemented Interfaces:

Serializable, Cloneable
```
public final class BitString
extends Object
implements Cloneable, Serializable
```
BitString implements a vector of bits much like java.util.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.
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.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`class`	`BitString.BackwardBitStringIterator`	Iterator for iterating through a bit string in backward order.
`static class`	`BitString.BitStringIterator`	Abstract bit string iterator class.
`class`	`BitString.ForwardBitStringIterator`	Iterator for iterating through a bit string in forward order.
`class`	`BitString.ForwardBitStringZeroIterator`	Iterator for iterating through a bit string in forward order.

Constructor Summary

Constructors
Constructor Description

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

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`and(BitString set)`	Logically ANDs this bit set with the specified set of bits.
`BitString.BackwardBitStringIterator`	`backwardsIterator()`	Returns an iterator that iterates through the bits in backward order.
`BitString.BackwardBitStringIterator`	`backwardsIterator(int i)`	Returns an iterator that iterates through the bits in backward order, starting at the given index.
`static int`	`bsf(int b)`	Utility function to return the index of the first (lowest-order) one bit in the given integer.
`static int`	`bsr(int v)`	Utility function to return the index of the last one bit in the given integer.
`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.
`Object`	`clone()`	Clones the BitString.
`boolean`	`contains(BitString other)`	Check if this set contains all bits of the given set.
`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()`	Returns whether this `BitString` is all zeroes.
`BitString.ForwardBitStringIterator`	`iterator()`	Returns an iterator that iterates through the bits in forward order.
`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.
`boolean`	`minus(BitString set)`	Logically subtracts this bit set with the specified set of bits.
`int`	`numberOfOnes()`	Returns the number of ones in this `BitString`.
`int`	`numberOfOnes(int where)`	Returns the number of ones in this `BitString` up to a given index.
`boolean`	`or(BitString set)`	Logically ORs this bit set with the specified set of bits.
`boolean`	`or_upTo(BitString set, int bit)`	Logically ORs this bit set with the specified set of bits.
`static byte`	`popcount(int b)`	Utility function to return the number of 1 bits in the given integer value.
`static byte`	`popcount(long b)`	Utility function to return the number of 1 bits in the given long value.
`void`	`set(int bit)`	Sets a bit.
`void`	`setAll()`	Sets all bits.
`void`	`setRange(int lo, int hi)`
`void`	`setUpTo(int bit)`	Sets all bits up to and including the given bit.
`void`	`shl(int amt)`	Performs a left-shift operation.
`void`	`shr(int amt)`	Performs a right-shift operation.
`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.
`BitString.ForwardBitStringZeroIterator`	`zeroIterator()`

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.
    
    Returns:
    
    the first 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.
    
    Returns:
    
    the first index
  - popcount
```
public static final byte popcount(int b)
```
    Utility function to return the number of 1 bits in the given integer value.
    
    Parameters:
    
    b - value to check
    
    Returns:
    
    byte number of one bits
  - popcount
```
public static final byte popcount(long b)
```
    Utility function to return the number of 1 bits in the given long value.
    
    Parameters:
    
    b - value to check
    
    Returns:
    
    byte number of one bits
  - bsf
```
public static final int bsf(int b)
```
    Utility function to return the index of the first (lowest-order) one bit in the given integer. Returns zero if the given number is zero.
    
    Parameters:
    
    b - value to check
    
    Returns:
    
    byte index of first one bit, or zero if the number is zero
  - bsr
```
public static final int bsr(int v)
```
    Utility function to return the index of the last one bit in the given integer. Returns zero if the given number is zero.
    
    Parameters:
    
    v - value to check
    
    Returns:
    
    byte index of first one bit, or zero if the number is zero
  - 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.
    
    Returns:
    
    last index
  - lastSet
```
public int lastSet()
```
    Returns the last index in the bit string which is set, or -1 if there is no such index.
    
    Returns:
    
    last 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)
  - setRange
```
public void setRange(int lo,
                     int hi)
```
  - 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)
    
    Returns:
    
    the bit
  - 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
    
    Returns:
    
    modified
  - 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
    
    Returns:
    
    modified
  - 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
    
    Returns:
    
    modified
  - 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
    
    Returns:
    
    modified
  - minus
```
public boolean minus(BitString set)
```
    Logically subtracts 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 subtract
    
    Returns:
    
    modified
  - intersectionEmpty
```
public boolean intersectionEmpty(BitString other)
```
    Check if the intersection of the two sets is empty.
    
    Parameters:
    
    other - the set to check intersection with
    
    Returns:
    
    is empty or not
  - contains
```
public boolean contains(BitString other)
```
    Check if this set contains all bits of the given set.
    
    Parameters:
    
    other - the set to check containment with
    
    Returns:
    
    contains or not
  - shl
```
public void shl(int amt)
```
    Performs a left-shift operation.
    
    Parameters:
    
    amt - number of bits to shift, can be negative
  - shr
```
public void shr(int amt)
```
    Performs a right-shift operation.
    
    Parameters:
    
    amt - number of bits to shift
  - 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.
    
    Returns:
    
    logical size
  - 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.
    
    Returns:
    
    number of bits
  - 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()
```
    Returns whether this BitString is all zeroes.
    
    Returns:
    
    true if it is all zeroes.
  - numberOfOnes
```
public int numberOfOnes()
```
    Returns the number of ones in this BitString.
    
    Returns:
    
    number of bits set.
  - numberOfOnes
```
public int numberOfOnes(int where)
```
    Returns the number of ones in this BitString up to a given index.
    
    Returns:
    
    number of bits set.
  - clone
```
public Object clone()
```
    Clones the BitString.
    
    Overrides:
    
    clone in class Object
  - toString
```
public String toString()
```
    Converts the BitString to a String.
    
    Overrides:
    
    toString in class Object
  - iterator
```
public BitString.ForwardBitStringIterator iterator()
```
    Returns an iterator that iterates through the bits in forward order.
    
    Returns:
    
    an iterator
  - zeroIterator
```
public BitString.ForwardBitStringZeroIterator zeroIterator()
```
  - backwardsIterator
```
public BitString.BackwardBitStringIterator backwardsIterator()
```
    Returns an iterator that iterates through the bits in backward order.
    
    Returns:
    
    an iterator
  - backwardsIterator
```
public BitString.BackwardBitStringIterator backwardsIterator(int i)
```
    Returns an iterator that iterates through the bits in backward order, starting at the given index.
    
    Returns:
    
    an iterator

Class BitString

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BitString

Method Detail

firstSet

firstSet

popcount

popcount

bsf

bsr

lastSet

lastSet

setAll

setUpTo

setRange

set

clearAll

clearUpTo

clear

get

and

or

or_upTo

xor

minus

intersectionEmpty

contains

shl

shr

copyBits

hashCode

length

size

equals

isZero

numberOfOnes

numberOfOnes

clone

toString

iterator

zeroIterator

backwardsIterator

backwardsIterator