org.roaringbitmap

Class Util

java.lang.Object

org.roaringbitmap.Util

public final class Util
extends Object

Various useful methods for roaring bitmaps.

Method Summary

Modifier and Type	Method and Description
static void	fillArrayAND(short[] container, long[] bitmap1, long[] bitmap2) Compute the bitwise AND between two long arrays and write the set bits in the container.
static void	fillArrayANDNOT(short[] container, long[] bitmap1, long[] bitmap2) Compute the bitwise ANDNOT between two long arrays and write the set bits in the container.
static void	fillArrayXOR(short[] container, long[] bitmap1, long[] bitmap2) Compute the bitwise XOR between two long arrays and write the set bits in the container.
protected static short	highbits(int x)
protected static short	lowbits(int x)
protected static short	maxLowBit()
static int	select(int w, int j) Given a word w, return the position of the jth true bit.
static int	select(long w, int j) Given a word w, return the position of the jth true bit.
static int	select(short w, int j) Given a word w, return the position of the jth true bit.
protected static int	toIntUnsigned(short x)
protected static int	unsignedBinarySearch(short[] array, int begin, int end, short k)
static int	unsignedDifference(short[] set1, int length1, short[] set2, int length2, short[] buffer) Compute the difference between two sorted lists and write the result to the provided output array
static int	unsignedExclusiveUnion2by2(short[] set1, int length1, short[] set2, int length2, short[] buffer) Compute the exclusive union of two sorted lists and write the result to the provided output array
static int	unsignedIntersect2by2(short[] set1, int length1, short[] set2, int length2, short[] buffer) Intersect two sorted lists and write the result to the provided output array
protected static int	unsignedLocalIntersect2by2(short[] set1, int length1, short[] set2, int length2, short[] buffer)
protected static int	unsignedOneSidedGallopingIntersect2by2(short[] smallSet, int smallLength, short[] largeSet, int largeLength, short[] buffer)
static int	unsignedUnion2by2(short[] set1, int length1, short[] set2, int length2, short[] buffer) Unite two sorted lists and write the result to the provided output array

Methods inherited from class java.lang.Object

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

Method Detail

fillArrayAND

public static void fillArrayAND(short[] container,
                                long[] bitmap1,
                                long[] bitmap2)

Compute the bitwise AND between two long arrays and write the set bits in the container.

Parameters:

container - where we write

bitmap1 - first bitmap

bitmap2 - second bitmap

fillArrayANDNOT

public static void fillArrayANDNOT(short[] container,
                                   long[] bitmap1,
                                   long[] bitmap2)

Compute the bitwise ANDNOT between two long arrays and write the set bits in the container.

Parameters:

container - where we write

bitmap1 - first bitmap

bitmap2 - second bitmap

fillArrayXOR

public static void fillArrayXOR(short[] container,
                                long[] bitmap1,
                                long[] bitmap2)

Compute the bitwise XOR between two long arrays and write the set bits in the container.

Parameters:

container - where we write

bitmap1 - first bitmap

bitmap2 - second bitmap

highbits

protected static short highbits(int x)

lowbits

protected static short lowbits(int x)

maxLowBit

protected static short maxLowBit()

toIntUnsigned

protected static int toIntUnsigned(short x)

unsignedBinarySearch

protected static int unsignedBinarySearch(short[] array,
                                          int begin,
                                          int end,
                                          short k)

unsignedDifference

public static int unsignedDifference(short[] set1,
                                     int length1,
                                     short[] set2,
                                     int length2,
                                     short[] buffer)

Compute the difference between two sorted lists and write the result to the provided output array

Parameters:

set1 - first array

length1 - length of first array

set2 - second array

length2 - length of second array

buffer - output array

Returns:

cardinality of the difference

unsignedExclusiveUnion2by2

public static int unsignedExclusiveUnion2by2(short[] set1,
                                             int length1,
                                             short[] set2,
                                             int length2,
                                             short[] buffer)

Compute the exclusive union of two sorted lists and write the result to the provided output array

Parameters:

set1 - first array

length1 - length of first array

set2 - second array

length2 - length of second array

buffer - output array

Returns:

cardinality of the exclusive union

unsignedIntersect2by2

public static int unsignedIntersect2by2(short[] set1,
                                        int length1,
                                        short[] set2,
                                        int length2,
                                        short[] buffer)

Intersect two sorted lists and write the result to the provided output array

Parameters:

set1 - first array

length1 - length of first array

set2 - second array

length2 - length of second array

buffer - output array

Returns:

cardinality of the intersection

unsignedLocalIntersect2by2

protected static int unsignedLocalIntersect2by2(short[] set1,
                                                int length1,
                                                short[] set2,
                                                int length2,
                                                short[] buffer)

unsignedOneSidedGallopingIntersect2by2

protected static int unsignedOneSidedGallopingIntersect2by2(short[] smallSet,
                                                            int smallLength,
                                                            short[] largeSet,
                                                            int largeLength,
                                                            short[] buffer)

unsignedUnion2by2

public static int unsignedUnion2by2(short[] set1,
                                    int length1,
                                    short[] set2,
                                    int length2,
                                    short[] buffer)

Unite two sorted lists and write the result to the provided output array

Parameters:

set1 - first array

length1 - length of first array

set2 - second array

length2 - length of second array

buffer - output array

Returns:

cardinality of the union

select

public static int select(long w,
                         int j)

Given a word w, return the position of the jth true bit.

Parameters:

w - word

j - index

Returns:

position of jth true bit in w

select

public static int select(int w,
                         int j)

Given a word w, return the position of the jth true bit.

Parameters:

w - word

j - index

Returns:

position of jth true bit in w

select

public static int select(short w,
                         int j)

Given a word w, return the position of the jth true bit.

Parameters:

w - word

j - index

Returns:

position of jth true bit in w