org.roaringbitmap.buffer

Class BufferUtil

java.lang.Object

org.roaringbitmap.buffer.BufferUtil

public final class BufferUtil
extends Object

Various useful methods for roaring bitmaps. This class is similar to org.roaringbitmap.Util but meant to be used with memory mapping.

Field Summary

Fields

Modifier and Type	Field and Description
protected static boolean	USE_HYBRID_BINSEARCH

Method Summary

Modifier and Type	Method and Description
protected static int	advanceUntil(ShortBuffer array, int pos, int length, short min) Find the smallest integer larger than pos such that array[pos]>= min.
protected static void	arraycopy(ShortBuffer src, int srcPos, ShortBuffer dest, int destPos, int length)
protected static int	branchyUnsignedBinarySearch(ShortBuffer array, int begin, int end, short k)
static int	compareUnsigned(short a, short b) Compares the two specified short values, treating them as unsigned values between 0 and 2^16 - 1 inclusive.
protected static void	fillArrayAND(short[] container, LongBuffer bitmap1, LongBuffer bitmap2)
protected static void	fillArrayANDNOT(short[] container, LongBuffer bitmap1, LongBuffer bitmap2)
protected static void	fillArrayXOR(short[] container, LongBuffer bitmap1, LongBuffer bitmap2)
static void	flipBitmapRange(LongBuffer bitmap, int start, int end) flip bits at start, start+1,..., end-1
protected static int	getSizeInBytesFromCardinalityEtc(int card, int numRuns, boolean isRunEncoded) From the cardinality of a container, compute the corresponding size in bytes of the container.
protected static short	highbits(int x)
protected static int	hybridUnsignedBinarySearch(ShortBuffer array, int begin, int end, short k)
protected static boolean	isBackedBySimpleArray(Buffer b)
protected static short	lowbits(int x)
protected static short	maxLowBit()
protected static int	maxLowBitAsInteger()
protected static int	oldunsignedOneSidedGallopingIntersect2by2(ShortBuffer smallSet, int smallLength, ShortBuffer largeSet, int largeLength, short[] buffer)
static void	resetBitmapRange(LongBuffer bitmap, int start, int end) clear bits at start, start+1,..., end-1
static void	setBitmapRange(LongBuffer bitmap, int start, int end) set bits at start, start+1,..., end-1
protected static int	toIntUnsigned(short x)
static int	unsignedBinarySearch(ShortBuffer array, int begin, int end, short k) Look for value k in buffer in the range [begin,end).
protected static int	unsignedDifference(ShortBuffer set1, int length1, ShortBuffer set2, int length2, short[] buffer)
protected static int	unsignedExclusiveUnion2by2(ShortBuffer set1, int length1, ShortBuffer set2, int length2, short[] buffer)
protected static int	unsignedIntersect2by2(ShortBuffer set1, int length1, ShortBuffer set2, int length2, short[] buffer)
static boolean	unsignedIntersects(ShortBuffer set1, int length1, ShortBuffer set2, int length2) Checks if two arrays intersect
protected static int	unsignedLocalIntersect2by2(ShortBuffer set1, int length1, ShortBuffer set2, int length2, short[] buffer)
protected static int	unsignedOneSidedGallopingIntersect2by2(ShortBuffer smallSet, int smallLength, ShortBuffer largeSet, int largeLength, short[] buffer)
protected static int	unsignedUnion2by2(ShortBuffer set1, int length1, ShortBuffer set2, int length2, short[] buffer)

Methods inherited from class java.lang.Object

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

Field Detail

USE_HYBRID_BINSEARCH

protected static boolean USE_HYBRID_BINSEARCH

Method Detail

flipBitmapRange

public static void flipBitmapRange(LongBuffer bitmap,
                                   int start,
                                   int end)

flip bits at start, start+1,..., end-1

Parameters:

bitmap - array of words to be modified

start - first index to be modified (inclusive)

end - last index to be modified (exclusive)

resetBitmapRange

public static void resetBitmapRange(LongBuffer bitmap,
                                    int start,
                                    int end)

clear bits at start, start+1,..., end-1

Parameters:

bitmap - array of words to be modified

start - first index to be modified (inclusive)

end - last index to be modified (exclusive)

setBitmapRange

public static void setBitmapRange(LongBuffer bitmap,
                                  int start,
                                  int end)

set bits at start, start+1,..., end-1

Parameters:

bitmap - array of words to be modified

start - first index to be modified (inclusive)

end - last index to be modified (exclusive)

advanceUntil

protected static int advanceUntil(ShortBuffer array,
                                  int pos,
                                  int length,
                                  short min)

Find the smallest integer larger than pos such that array[pos]>= min. If none can be found, return length. Based on code by O. Kaser.

Parameters:

array - container where we search

pos - initial position

min - minimal threshold

length - how big should the array consider to be

Returns:

x greater than pos such that array[pos] is at least as large as min, pos is is equal to length if it is not possible.

fillArrayAND

protected static void fillArrayAND(short[] container,
                                   LongBuffer bitmap1,
                                   LongBuffer bitmap2)

fillArrayANDNOT

protected static void fillArrayANDNOT(short[] container,
                                      LongBuffer bitmap1,
                                      LongBuffer bitmap2)

fillArrayXOR

protected static void fillArrayXOR(short[] container,
                                   LongBuffer bitmap1,
                                   LongBuffer bitmap2)

getSizeInBytesFromCardinalityEtc

protected static int getSizeInBytesFromCardinalityEtc(int card,
                                                      int numRuns,
                                                      boolean isRunEncoded)

From the cardinality of a container, compute the corresponding size in bytes of the container. Additional information is required if the container is run encoded.

Parameters:

card - the cardinality if this is not run encoded, otherwise ignored

numRuns - number of runs if run encoded, othewise ignored

isRunEncoded - boolean

Returns:

the size in bytes

isBackedBySimpleArray

protected static boolean isBackedBySimpleArray(Buffer b)

highbits

protected static short highbits(int x)

lowbits

protected static short lowbits(int x)

maxLowBit

protected static short maxLowBit()

maxLowBitAsInteger

protected static int maxLowBitAsInteger()

arraycopy

protected static void arraycopy(ShortBuffer src,
                                int srcPos,
                                ShortBuffer dest,
                                int destPos,
                                int length)

toIntUnsigned

protected static int toIntUnsigned(short x)

unsignedBinarySearch

public static int unsignedBinarySearch(ShortBuffer array,
                                       int begin,
                                       int end,
                                       short k)

Look for value k in buffer in the range [begin,end). If the value is found, return its index. If not, return -(i+1) where i is the index where the value would be inserted. The buffer is assumed to contain sorted values where shorts are interpreted as unsigned integers.

Parameters:

array - buffer where we search

begin - first index (inclusive)

end - last index (exclusive)

k - value we search for

Returns:

count

hybridUnsignedBinarySearch

protected static int hybridUnsignedBinarySearch(ShortBuffer array,
                                                int begin,
                                                int end,
                                                short k)

branchyUnsignedBinarySearch

protected static int branchyUnsignedBinarySearch(ShortBuffer array,
                                                 int begin,
                                                 int end,
                                                 short k)

unsignedDifference

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

unsignedExclusiveUnion2by2

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

unsignedIntersect2by2

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

unsignedOneSidedGallopingIntersect2by2

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

unsignedLocalIntersect2by2

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

oldunsignedOneSidedGallopingIntersect2by2

protected static int oldunsignedOneSidedGallopingIntersect2by2(ShortBuffer smallSet,
                                                               int smallLength,
                                                               ShortBuffer largeSet,
                                                               int largeLength,
                                                               short[] buffer)

unsignedUnion2by2

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

compareUnsigned

public static int compareUnsigned(short a,
                                  short b)

Compares the two specified short values, treating them as unsigned values between 0 and 2^16 - 1 inclusive.

Parameters:

a - the first unsigned short to compare

b - the second unsigned short to compare

Returns:

a negative value if a is less than b; a positive value if a is greater than b; or zero if they are equal

unsignedIntersects

public static boolean unsignedIntersects(ShortBuffer set1,
                                         int length1,
                                         ShortBuffer set2,
                                         int length2)

Checks if two arrays intersect

Parameters:

set1 - first array

length1 - length of first array

set2 - second array

length2 - length of second array

Returns:

true if they intersect