Module roaringbitmap

Package org.roaringbitmap

Class BitSetUtil

java.lang.Object

org.roaringbitmap.BitSetUtil

public class BitSetUtil
extends Object

This class provides convenience functions to manipulate BitSet and RoaringBitmap objects.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BLOCK_LENGTH

Constructor Summary

Constructors

Constructor	Description
BitSetUtil()

Method Summary

Modifier and Type	Method	Description
static char[]	arrayContainerBufferOf(int from, int to, int cardinality, long[] words)	Creates array container's content char buffer.
static RoaringBitmap	bitmapOf(long[] words)	Generate a RoaringBitmap out of a long[], each long using little-endian representation of its bits
static RoaringBitmap	bitmapOf(ByteBuffer bb, boolean fastRank)	Efficiently generate a RoaringBitmap from an uncompressed byte array or ByteBuffer This method tries to minimise all kinds of memory allocation
static RoaringBitmap	bitmapOf(ByteBuffer bb, boolean fastRank, long[] wordsBuffer)	Efficiently generate a RoaringBitmap from an uncompressed byte array or ByteBuffer This method tries to minimise all kinds of memory allocation You can provide a cached wordsBuffer for avoiding 8 KB of extra allocation on every call No reference is kept to the wordsBuffer, so it can be cached as a ThreadLocal
static RoaringBitmap	bitmapOf(BitSet bitSet)	Generate a RoaringBitmap out of a BitSet
static BitSet	bitsetOf(RoaringBitmap bitmap)	Convert a RoaringBitmap to a BitSet.
static BitSet	bitsetOfWithoutCopy(RoaringBitmap bitmap)	Convert a RoaringBitmap to a BitSet without copying to an intermediate array.
static boolean	equals(BitSet bitset, RoaringBitmap bitmap)	Compares a RoaringBitmap and a BitSet.
static byte[]	toByteArray(RoaringBitmap bitmap)	Returns an array of little-endian ordered bytes, given a RoaringBitmap.
static long[]	toLongArray(RoaringBitmap bitmap)	Returns an array of long, given a RoaringBitmap.

Methods inherited from class java.lang.Object

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

Field Details

BLOCK_LENGTH

public static final int BLOCK_LENGTH

See Also:

• Constant Field Values

Constructor Details

BitSetUtil

public BitSetUtil()

Method Details

bitsetOf

public static BitSet bitsetOf(RoaringBitmap bitmap)

Convert a RoaringBitmap to a BitSet.

Equivalent to calling BitSet.valueOf(BitSetUtil.toLongArray(bitmap)).

bitsetOfWithoutCopy

public static BitSet bitsetOfWithoutCopy(RoaringBitmap bitmap)

Convert a RoaringBitmap to a BitSet without copying to an intermediate array.

toByteArray

public static byte[] toByteArray(RoaringBitmap bitmap)

Returns an array of little-endian ordered bytes, given a RoaringBitmap.

See BitSet.toByteArray().

toLongArray

public static long[] toLongArray(RoaringBitmap bitmap)

Returns an array of long, given a RoaringBitmap.

See BitSet.toLongArray().

arrayContainerBufferOf

public static char[] arrayContainerBufferOf(int from,
 int to,
 int cardinality,
 long[] words)

Creates array container's content char buffer.

Parameters:

from - first value of the range

to - last value of the range

cardinality - new buffer cardinality, expected to be less than 4096 and more than present values in given bitmap

words - bitmap

Returns:

array container's content char buffer

bitmapOf

public static RoaringBitmap bitmapOf(BitSet bitSet)

Generate a RoaringBitmap out of a BitSet

Parameters:

bitSet - original bitset (will not be modified)

Returns:

roaring bitmap equivalent to BitSet

bitmapOf

public static RoaringBitmap bitmapOf(long[] words)

Generate a RoaringBitmap out of a long[], each long using little-endian representation of its bits

Parameters:

words - array of longs (will not be modified)

Returns:

roaring bitmap

See Also:

• for an equivalent

bitmapOf

public static RoaringBitmap bitmapOf(ByteBuffer bb,
 boolean fastRank)

Efficiently generate a RoaringBitmap from an uncompressed byte array or ByteBuffer This method tries to minimise all kinds of memory allocation

Parameters:

bb - the uncompressed bitmap

fastRank - if set, returned bitmap is of type FastRankRoaringBitmap

Returns:

roaring bitmap

bitmapOf

public static RoaringBitmap bitmapOf(ByteBuffer bb,
 boolean fastRank,
 long[] wordsBuffer)

Efficiently generate a RoaringBitmap from an uncompressed byte array or ByteBuffer This method tries to minimise all kinds of memory allocation
You can provide a cached wordsBuffer for avoiding 8 KB of extra allocation on every call No reference is kept to the wordsBuffer, so it can be cached as a ThreadLocal

Parameters:

bb - the uncompressed bitmap

fastRank - if set, returned bitmap is of type FastRankRoaringBitmap

wordsBuffer - buffer of length BLOCK_LENGTH

Returns:

roaring bitmap

equals

public static boolean equals(BitSet bitset,
 RoaringBitmap bitmap)

Compares a RoaringBitmap and a BitSet. They are equal if and only if they contain the same set of integers.

Parameters:

bitset - first object to be compared

bitmap - second object to be compared

Returns:

whether they are equals