me.lemire.integercompression
Class Delta

java.lang.Object
  me.lemire.integercompression.Delta

public final class Delta
extends Object

Generic class to compute differential coding.

Author:

Daniel Lemire

Constructor Summary

Delta()

Method Summary

static void	delta(int[] data) Apply differential coding (in-place).
static int	delta(int[] data, int start, int length, int init) Apply differential coding (in-place) given an initial value.
static int	delta(int[] data, int start, int length, int init, int[] out) Compute differential coding given an initial value.
static void	fastinverseDelta(int[] data) Undo differential coding (in-place).
static int	fastinverseDelta(int[] data, int start, int length, int init) Undo differential coding (in-place).
static void	inverseDelta(int[] data) Undo differential coding (in-place).

Methods inherited from class java.lang.Object

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

Constructor Detail

Delta

public Delta()

Method Detail

delta

public static void delta(int[] data)

Apply differential coding (in-place).

Parameters:

data - data to be modified

delta

public static int delta(int[] data,
                        int start,
                        int length,
                        int init)

Apply differential coding (in-place) given an initial value.

Parameters:

data - data to be modified

start - starting index

length - number of integers to process

init - initial value

Returns:

next initial vale

delta

public static int delta(int[] data,
                        int start,
                        int length,
                        int init,
                        int[] out)

Compute differential coding given an initial value. Output is written to a provided array: must have length "length" or better.

Parameters:

data - data to be modified

start - starting index

length - number of integers to process

init - initial value

out - output array

Returns:

next initial vale

inverseDelta

public static void inverseDelta(int[] data)

Undo differential coding (in-place). Effectively computes a prefix sum.

Parameters:

data - to be modified.

fastinverseDelta

public static void fastinverseDelta(int[] data)

Undo differential coding (in-place). Effectively computes a prefix sum. Like inverseDelta, only faster.

Parameters:

data - to be modified

fastinverseDelta

public static int fastinverseDelta(int[] data,
                                   int start,
                                   int length,
                                   int init)

Undo differential coding (in-place). Effectively computes a prefix sum. Like inverseDelta, only faster. Uses an initial value.

Parameters:

data - to be modified

start - starting index

length - number of integers to process

init - initial value

Returns:

next initial value