Module org.apache.lucene.core

Package org.apache.lucene.codecs.lucene101

Class ForDeltaUtil

java.lang.Object

org.apache.lucene.codecs.lucene101.ForDeltaUtil

public final class ForDeltaUtil
extends Object

Inspired from https://fulmicoton.com/posts/bitpacking/ Encodes multiple integers in a Java int to get SIMD-like speedups. If bitsPerValue <= 4 then we pack 4 ints per Java int else if bitsPerValue <= 11 we pack 2 ints per Java int else we use scalar operations.

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	HALF_BLOCK_SIZE
private static final int[]	IDENTITY_PLUS_ONE
private static final int	ONE_BLOCK_SIZE_FOURTH
private static final int	THREE_BLOCK_SIZE_FOURTHS
private final int[]	tmp
private static final int	TWO_BLOCK_SIZE_FOURTHS

Constructor Summary

Constructors

Constructor	Description
ForDeltaUtil()

Method Summary

Modifier and Type	Method	Description
private static void	decode11To32(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode12To32(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode13To32(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode14To32(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode15To32(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode16To32(PostingDecodingUtil pdu, int[] ints)
private static void	decode4To16(PostingDecodingUtil pdu, int[] ints)
private static void	decode5To16(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode6To16(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode7To16(PostingDecodingUtil pdu, int[] tmp, int[] ints)
private static void	decode8To16(PostingDecodingUtil pdu, int[] ints)
(package private) void	decodeAndPrefixSum(int bitsPerValue, PostingDecodingUtil pdu, int base, int[] ints)	Delta-decode 128 integers into ints.
(package private) void	decodeAndPrefixSum(PostingDecodingUtil pdu, int base, int[] ints)	Decode deltas, compute the prefix sum and add base to all decoded ints.
(package private) void	encodeDeltas(int[] ints, DataOutput out)	Encode deltas of a strictly monotonically increasing sequence of integers.
private static void	innerPrefixSum16(int[] arr)
private static void	innerPrefixSum8(int[] arr)
private static void	prefixSum16(int[] arr, int base)
private static void	prefixSum32(int[] arr, int base)
private static void	prefixSum8(int[] arr, int base)
private static void	prefixSumOfOnes(int[] arr, int base)

Methods inherited from class java.lang.Object

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

Field Details

HALF_BLOCK_SIZE

private static final int HALF_BLOCK_SIZE

See Also:

• Constant Field Values

ONE_BLOCK_SIZE_FOURTH

private static final int ONE_BLOCK_SIZE_FOURTH

See Also:

• Constant Field Values

TWO_BLOCK_SIZE_FOURTHS

private static final int TWO_BLOCK_SIZE_FOURTHS

See Also:

• Constant Field Values

THREE_BLOCK_SIZE_FOURTHS

private static final int THREE_BLOCK_SIZE_FOURTHS

See Also:

• Constant Field Values

IDENTITY_PLUS_ONE

private static final int[] IDENTITY_PLUS_ONE

tmp

private final int[] tmp

Constructor Details

ForDeltaUtil

public ForDeltaUtil()

Method Details

prefixSumOfOnes

private static void prefixSumOfOnes(int[] arr,
 int base)

prefixSum8

private static void prefixSum8(int[] arr,
 int base)

prefixSum16

private static void prefixSum16(int[] arr,
 int base)

prefixSum32

private static void prefixSum32(int[] arr,
 int base)

innerPrefixSum8

private static void innerPrefixSum8(int[] arr)

innerPrefixSum16

private static void innerPrefixSum16(int[] arr)

encodeDeltas

void encodeDeltas(int[] ints,
 DataOutput out)
           throws IOException

Encode deltas of a strictly monotonically increasing sequence of integers. The provided ints are expected to be deltas between consecutive values.

Throws:

IOException

decodeAndPrefixSum

void decodeAndPrefixSum(PostingDecodingUtil pdu,
 int base,
 int[] ints)
                 throws IOException

Decode deltas, compute the prefix sum and add base to all decoded ints.

Throws:

IOException

decodeAndPrefixSum

void decodeAndPrefixSum(int bitsPerValue,
 PostingDecodingUtil pdu,
 int base,
 int[] ints)
                 throws IOException

Delta-decode 128 integers into ints.

Throws:

IOException

decode4To16

private static void decode4To16(PostingDecodingUtil pdu,
 int[] ints)
                         throws IOException

Throws:

IOException

decode5To16

private static void decode5To16(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                         throws IOException

Throws:

IOException

decode6To16

private static void decode6To16(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                         throws IOException

Throws:

IOException

decode7To16

private static void decode7To16(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                         throws IOException

Throws:

IOException

decode8To16

private static void decode8To16(PostingDecodingUtil pdu,
 int[] ints)
                         throws IOException

Throws:

IOException

decode11To32

private static void decode11To32(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                          throws IOException

Throws:

IOException

decode12To32

private static void decode12To32(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                          throws IOException

Throws:

IOException

decode13To32

private static void decode13To32(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                          throws IOException

Throws:

IOException

decode14To32

private static void decode14To32(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                          throws IOException

Throws:

IOException

decode15To32

private static void decode15To32(PostingDecodingUtil pdu,
 int[] tmp,
 int[] ints)
                          throws IOException

Throws:

IOException

decode16To32

private static void decode16To32(PostingDecodingUtil pdu,
 int[] ints)
                          throws IOException

Throws:

IOException