BS

java.lang.Object
- org.jmol.java.BS

All Implemented Interfaces:

java.lang.Cloneable, javajs.api.JSONEncodable

Direct Known Subclasses:

BondSet
```
public class BS
extends java.lang.Object
implements java.lang.Cloneable, javajs.api.JSONEncodable
```
a fast 64-bit BitSet optimized as 32-bit in Java2Script -- about 25 times faster than java.util.BitSet in JavaScript.

Since:

JDK1.0

Author:

Bob Hanson hansonr@stolaf.edu This class implements a 64-bit vector of bits that grows as needed. Each component of the bit set has a boolean value. The bits of a BitSet are indexed by nonnegative integers. Individual be used to modify the contents of another BitSet 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 relates to logical length of a bit set and is defined independently of implementation.
Unless otherwise noted, passing a null parameter to any of the methods in a BitSet will result in a NullPointerException.
A BitSet is not safe for multithreaded use without external synchronization., Arthur van Hoff, Michael McCloskey, Martin Buchholz

Field Summary

Fields
Modifier and Type	Field and Description
`private static int`	`ADDRESS_BITS_PER_WORD`
`private static int`	`BITS_PER_WORD`
`private static long[]`	`emptyBitmap`
`private boolean`	`sizeIsSticky` Whether the size of "words" is user-specified.
`private static long`	`WORD_MASK`
`private long[]`	`words` The internal field corresponding to the serialField "bits".
`private int`	`wordsInUse` The number of words in the logical size of this BitSet.

Constructor Summary

Constructors
Constructor and Description

BS()
Creates a new bit set.

Constructors
Constructor and Description
`BS()` Creates a new bit set.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`and(BS set)` Performs a logical AND of this target bit set with the argument bit set.
`void`	`andNot(BS set)` Clears all of the bits in this `BitSet` whose corresponding bit is set in the specified `BitSet`.
`int`	`cardinality()` Returns the number of bits set to `true` in this `BitSet`.
`int`	`cardinalityN(int max)`
`void`	`clear(int bitIndex)` Sets the bit specified by the index to `false`.
`void`	`clearAll()` Sets all of the bits in this BitSet to `false`.
`void`	`clearBits(int fromIndex, int toIndex)` Sets the bits from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to `false`.
`java.lang.Object`	`clone()` Cloning this `BitSet` produces a new `BitSet` that is equal to it.
`private void`	`ensureCapacity(int wordsRequired)` Ensures that the BitSet can hold enough words.
`boolean`	`equals(java.lang.Object obj)` Compares this object against the specified object.
`static java.lang.String`	`escape(BS bs, char chOpen, char chClose)`
`private void`	`expandTo(int wordIndex)` Ensures that the BitSet can accommodate a given wordIndex, temporarily violating the invariants.
`boolean`	`get(int bitIndex)` Returns the value of the bit with the specified index.
`int`	`hashCode()` Returns a hash code value for this bit set.
`private void`	`init(int nbits)`
`private void`	`initWords(int nbits)`
`boolean`	`intersects(BS set)` Returns true if the specified `BitSet` has any bits set to `true` that are also set to `true` in this `BitSet`.
`boolean`	`isEmpty()` Returns true if this `BitSet` contains no bits that are set to `true`.
`int`	`length()` Returns the "logical size" of this `BitSet`: the index of the highest set bit in the `BitSet` plus one.
`static BS`	`newN(int nbits)` Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range `0` through `nbits-1`.
`int`	`nextClearBit(int fromIndex)` Returns the index of the first bit that is set to `false` that occurs on or after the specified starting index.
`int`	`nextSetBit(int fromIndex)` Returns the index of the first bit that is set to `true` that occurs on or after the specified starting index.
`void`	`or(BS set)` Performs a logical OR of this bit set with the bit set argument.
`private void`	`recalculateWordsInUse()` Sets the field wordsInUse to the logical size in words of the bit set.
`void`	`set(int bitIndex)` Sets the bit at the specified index to `true`.
`void`	`setBits(int fromIndex, int toIndex)` Sets the bits from the specified `fromIndex` (inclusive) to the specified `toIndex` (exclusive) to `true`.
`void`	`setBitTo(int bitIndex, boolean value)` Sets the bit at the specified index to the specified value.
`private void`	`setLength(int n)`
`int`	`size()` Returns the number of bits of space actually in use by this `BitSet` to represent bit values.
`java.lang.String`	`toJSON()`
`java.lang.String`	`toString()` Returns a string representation of this bit set.
`static BS`	`unescape(java.lang.String str)` ({ 1 2 3:5 }) or ({null}) or [{ 1 2 3:5 }]
`private static int`	`wordIndex(int bitIndex)` Given a bit index, return word index containing it.
`void`	`xor(BS set)` Performs a logical XOR of this bit set with the bit set argument.

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

- Field Detail
  - ADDRESS_BITS_PER_WORD
```
private static final int ADDRESS_BITS_PER_WORD
```
    See Also:
    
    Constant Field Values
  - BITS_PER_WORD
```
private static final int BITS_PER_WORD
```
    See Also:
    
    Constant Field Values
  - WORD_MASK
```
private static final long WORD_MASK
```
    See Also:
    
    Constant Field Values
  - words
```
private long[] words
```
    The internal field corresponding to the serialField "bits".
  - wordsInUse
```
private transient int wordsInUse
```
    The number of words in the logical size of this BitSet.
  - sizeIsSticky
```
private transient boolean sizeIsSticky
```
    Whether the size of "words" is user-specified. If so, we assume the user knows what he's doing and try harder to preserve it.
  - emptyBitmap
```
private static final long[] emptyBitmap
```
- Constructor Detail
  - BS
```
public BS()
```
    Creates a new bit set. All bits are initially false.
- Method Detail
  - wordIndex
```
private static int wordIndex(int bitIndex)
```
    Given a bit index, return word index containing it.
    
    Parameters:
    
    bitIndex -
    
    Returns:
    
    index
  - newN
```
public static BS newN(int nbits)
```
    Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range 0 through nbits-1. All bits are initially false.
    
    Parameters:
    
    nbits - the initial size of the bit set
    
    Returns:
    
    bs
    
    Throws:
    
    java.lang.NegativeArraySizeException - if the specified initial size is negative
  - recalculateWordsInUse
```
private void recalculateWordsInUse()
```
    Sets the field wordsInUse to the logical size in words of the bit set. WARNING:This method assumes that the number of words actually in use is less than or equal to the current value of wordsInUse!
  - init
```
private void init(int nbits)
```
  - initWords
```
private void initWords(int nbits)
```
  - ensureCapacity
```
private void ensureCapacity(int wordsRequired)
```
    Ensures that the BitSet can hold enough words.
    
    Parameters:
    
    wordsRequired - the minimum acceptable number of words.
  - expandTo
```
private void expandTo(int wordIndex)
```
    Ensures that the BitSet can accommodate a given wordIndex, temporarily violating the invariants. The caller must restore the invariants before returning to the user, possibly using recalculateWordsInUse().
    
    Parameters:
    
    wordIndex - the index to be accommodated.
  - set
```
public void set(int bitIndex)
```
    Sets the bit at the specified index to true.
    
    Parameters:
    
    bitIndex - a bit index
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
    
    Since:
    
    JDK1.0
  - setBitTo
```
public void setBitTo(int bitIndex,
                     boolean value)
```
    Sets the bit at the specified index to the specified value.
    
    Parameters:
    
    bitIndex - a bit index
    
    value - a boolean value to set
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
    
    Since:
    
    1.4
  - setBits
```
public void setBits(int fromIndex,
                    int toIndex)
```
    Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to true.
    
    Parameters:
    
    fromIndex - index of the first bit to be set
    
    toIndex - index after the last bit to be set
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex
    
    Since:
    
    1.4
  - clear
```
public void clear(int bitIndex)
```
    Sets the bit specified by the index to false.
    
    Parameters:
    
    bitIndex - the index of the bit to be cleared
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
    
    Since:
    
    JDK1.0
  - clearBits
```
public void clearBits(int fromIndex,
                      int toIndex)
```
    Sets the bits from the specified fromIndex (inclusive) to the specified toIndex (exclusive) to false.
    
    Parameters:
    
    fromIndex - index of the first bit to be cleared
    
    toIndex - index after the last bit to be cleared
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex
    
    Since:
    
    1.4
  - clearAll
```
public void clearAll()
```
    Sets all of the bits in this BitSet to false.
    
    Since:
    
    1.4
  - get
```
public boolean get(int bitIndex)
```
    Returns the value of the bit with the specified index. The value is true if the bit with the index bitIndex is currently set in this BitSet; otherwise, the result is false.
    
    Parameters:
    
    bitIndex - the bit index
    
    Returns:
    
    the value of the bit with the specified index
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
  - nextSetBit
```
public int nextSetBit(int fromIndex)
```
    Returns the index of the first bit that is set to true that occurs on or after the specified starting index. If no such bit exists then -1 is returned.
    To iterate over the true bits in a BitSet, use the following loop:
    Parameters:
    
    fromIndex - the index to start checking from (inclusive)
    
    Returns:
    
    the index of the next set bit, or -1 if there is no such bit
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
    
    Since:
    
    1.4
  - nextClearBit
```
public int nextClearBit(int fromIndex)
```
    Returns the index of the first bit that is set to false that occurs on or after the specified starting index.
    
    Parameters:
    
    fromIndex - the index to start checking from (inclusive)
    
    Returns:
    
    the index of the next clear bit
    
    Throws:
    
    java.lang.IndexOutOfBoundsException - if the specified index is negative
    
    Since:
    
    1.4
  - length
```
public int length()
```
    Returns the "logical size" of this BitSet: the index of the highest set bit in the BitSet plus one. Returns zero if the BitSet contains no set bits.
    
    Returns:
    
    the logical size of this BitSet
    
    Since:
    
    1.2
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this BitSet contains no bits that are set to true.
    
    Returns:
    
    boolean indicating whether this BitSet is empty
    
    Since:
    
    1.4
  - intersects
```
public boolean intersects(BS set)
```
    Returns true if the specified BitSet has any bits set to true that are also set to true in this BitSet.
    
    Parameters:
    
    set - BitSet to intersect with
    
    Returns:
    
    boolean indicating whether this BitSet intersects the specified BitSet
    
    Since:
    
    1.4
  - cardinality
```
public int cardinality()
```
    Returns the number of bits set to true in this BitSet.
    
    Returns:
    
    the number of bits set to true in this BitSet
    
    Since:
    
    1.4
  - and
```
public void and(BS set)
```
    Performs a logical AND of this target bit set with the argument bit set. This bit set is modified so that each bit in it has the value true if and only if it both initially had the value true and the corresponding bit in the bit set argument also had the value true.
    
    Parameters:
    
    set - a bit set
  - or
```
public void or(BS set)
```
    Performs a logical OR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if it either already had the value true or the corresponding bit in the bit set argument has the value true.
    
    Parameters:
    
    set - a bit set
  - xor
```
public void xor(BS set)
```
    Performs a logical XOR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if one of the following statements holds:
    - The bit initially has the value true, and the corresponding bit in the argument has the value false.
    - The bit initially has the value false, and the corresponding bit in the argument has the value true.
    Parameters:
    
    set - a bit set
  - andNot
```
public void andNot(BS set)
```
    Clears all of the bits in this BitSet whose corresponding bit is set in the specified BitSet.
    
    Parameters:
    
    set - the BitSet with which to mask this BitSet
    
    Since:
    
    1.2
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for this bit set. The hash code depends only on which bits have been set within this BitSet. The algorithm used to compute it may be described as follows.
    Suppose the bits in the BitSet were to be stored in an array of long integers called, say, words, in such a manner that bit k is set in the BitSet (for nonnegative values of k) if and only if the expression
```
 ((k >> 6) < words.length) && ((words[k >> 6] & (1L << (bit & 0x3F))) != 0)
 
```
    is true. Then the following definition of the hashCode method would be a correct implementation of the actual algorithm:
```
 public int hashCode() {
  long h = 1234;
  for (int i = words.length; --i >= 0;) {
    h ˆ= words[i] * (i + 1);
  }
  return (int) ((h >> 32) ˆ h);
 }
 
```
    Note that the hash code values change if the set of bits is altered.
    Overrides the hashCode method of Object.
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    a hash code value for this bit set.
  - size
```
public int size()
```
    Returns the number of bits of space actually in use by this BitSet to represent bit values. The maximum element in the set is the size - 1st element.
    
    Returns:
    
    the number of bits currently in this bit set
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Compares this object against the specified object. The result is true if and only if the argument is not null and is a Bitset object that has exactly the same set of bits set to true as this bit set. That is, for every nonnegative int index k,
```
 ((BitSet) obj).get(k) == this.get(k)
 
```
    must be true. The current sizes of the two bit sets are not compared.
    Overrides:
    
    equals in class java.lang.Object
    
    Parameters:
    
    obj - the object to compare with
    
    Returns:
    
    true if the objects are the same; false otherwise
    
    See Also:
    
    size()
  - clone
```
public java.lang.Object clone()
```
    Cloning this BitSet produces a new BitSet that is equal to it. The clone of the bit set is another bit set that has exactly the same bits set to true as this bit set.
    
    Overrides:
    
    clone in class java.lang.Object
    
    Returns:
    
    a clone of this bit set
    
    See Also:
    
    size()
  - setLength
```
private void setLength(int n)
```
  - toString
```
public java.lang.String toString()
```
    Returns a string representation of this bit set. For every index for which this BitSet contains a bit in the set state, the decimal representation of that index is included in the result. Such indices are listed in order from lowest to highest, separated by ", " (a comma and a space) and surrounded by braces, resulting in the usual mathematical notation for a set of integers.
    Example:
```
 BitSet drPepper = new BitSet();
 
```
    Now drPepper.toString() returns empty braces.
```
 drPepper.set(2);
 
```
    Now drPepper.toString() returns "{2}".
```
 drPepper.set(4);
 drPepper.set(10);
 
```
    Now drPepper.toString() returns "{2, 4, 10}".
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a string representation of this bit set
  - cardinalityN
```
public int cardinalityN(int max)
```
    Parameters:
    
    max -
    
    Returns:
    
    n bits below max
  - toJSON
```
public java.lang.String toJSON()
```
    Specified by:
    
    toJSON in interface javajs.api.JSONEncodable
  - unescape
```
public static BS unescape(java.lang.String str)
```
    ({ 1 2 3:5 }) or ({null}) or [{ 1 2 3:5 }]
    
    Parameters:
    
    str -
    
    Returns:
    
    BS
  - escape
```
public static java.lang.String escape(BS bs,
                                      char chOpen,
                                      char chClose)
```

Class BS

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ADDRESS_BITS_PER_WORD

BITS_PER_WORD

WORD_MASK

words

wordsInUse

sizeIsSticky

emptyBitmap

Constructor Detail

BS

Method Detail

wordIndex

newN

recalculateWordsInUse

init

initWords

ensureCapacity

expandTo

set

setBitTo

setBits

clear

clearBits

clearAll

get

nextSetBit

nextClearBit

length

isEmpty

intersects

cardinality

and

or

xor

andNot

hashCode

size

equals

clone

setLength

toString

cardinalityN

toJSON

unescape

escape