me.lemire.integercompression

Class Util

java.lang.Object

me.lemire.integercompression.Util

public final class Util
extends Object

Routine utility functions.

Author:

Daniel Lemire

Constructor Summary

Constructors

Constructor and Description
Util()

Method Summary

Modifier and Type	Method and Description
static int	bits(int i) Compute the integer logarithms (ceil(log(x+1)) of a value
static int	greatestMultiple(int value, int factor) return floor(value / factor) * factor
static int	maxbits(int[] i, int pos, int length) Compute the maximum of the integer logarithms (ceil(log(x+1)) of a range of value
protected static int	maxbits32(int[] i, int pos)
static int	maxdiffbits(int initoffset, int[] i, int pos, int length) Compute the maximum of the integer logarithms (ceil(log(x+1)) of a the successive differences (deltas) of a range of value
protected static int	pack(int[] outputarray, int arraypos, int[] data, int datapos, int num, int b)
protected static int	packsize(int num, int b)
protected static int	packsizew(int num, int b)
protected static int	packw(int[] outputarray, int arraypos, int[] data, int num, int b)
protected static int	unpack(int[] sourcearray, int arraypos, int[] data, int datapos, int num, int b)
protected static int	unpackw(int[] sourcearray, int arraypos, int[] data, int num, int b)

Methods inherited from class java.lang.Object

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

Constructor Detail

Util

public Util()

Method Detail

maxbits

public static int maxbits(int[] i,
                          int pos,
                          int length)

Compute the maximum of the integer logarithms (ceil(log(x+1)) of a range of value

Parameters:

i - source array

pos - starting position

length - number of integers to consider

Returns:

integer logarithm

maxbits32

protected static int maxbits32(int[] i,
                               int pos)

maxdiffbits

public static int maxdiffbits(int initoffset,
                              int[] i,
                              int pos,
                              int length)

Compute the maximum of the integer logarithms (ceil(log(x+1)) of a the successive differences (deltas) of a range of value

Parameters:

initoffset - initial vallue for the computation of the deltas

i - source array

pos - starting position

length - number of integers to consider

Returns:

integer logarithm

bits

public static int bits(int i)

Compute the integer logarithms (ceil(log(x+1)) of a value

Parameters:

i - source value

Returns:

integer logarithm

packsize

protected static int packsize(int num,
                              int b)

pack

protected static int pack(int[] outputarray,
                          int arraypos,
                          int[] data,
                          int datapos,
                          int num,
                          int b)

unpack

protected static int unpack(int[] sourcearray,
                            int arraypos,
                            int[] data,
                            int datapos,
                            int num,
                            int b)

packsizew

protected static int packsizew(int num,
                               int b)

packw

protected static int packw(int[] outputarray,
                           int arraypos,
                           int[] data,
                           int num,
                           int b)

unpackw

protected static int unpackw(int[] sourcearray,
                             int arraypos,
                             int[] data,
                             int num,
                             int b)

greatestMultiple

public static int greatestMultiple(int value,
                                   int factor)

return floor(value / factor) * factor

Parameters:

value - numerator

factor - denominator

Returns:

greatest multiple of factor no larger than value