core/org.gnit.lucenekmp.util.packed/PackedInts

PackedInts

Simplistic compression for array of unsigned long values. Each value is >= 0 and <= a specified maximum value. The values are stored as packed ints, with each value consuming a fixed number of bits.

Types

Decoder

interface Decoder

A decoder for packed integers.

Encoder

interface Encoder

An encoder for packed integers.

Format

enum Format : Enum<PackedInts.Format>

A format to write packed ints.

FormatAndBits

data class FormatAndBits(val format: PackedInts.Format, val bitsPerValue: Int)

Simple class that holds a format and a number of bits per value.

Mutable

abstract class Mutable : PackedInts.Reader

A packed integer array that can be modified.

NullReader

class NullReader : PackedInts.Reader

A Reader which has all its values equal to 0 (bitsPerValue = 0).

Reader

abstract class Reader : Accountable

A read-only random access array of positive integers.

ReaderIterator

interface ReaderIterator

Run-once iterator interface, to decode previously saved PackedInts.

Writer

abstract class Writer

A write-once Writer.

Properties

CODEC_NAME

const val CODEC_NAME: String

COMPACT

const val COMPACT: Float = 0.0f

No memory overhead at all, but the returned implementation may be slow.

DEFAULT

const val DEFAULT: Float = 0.25f

At most 25% memory overhead.

DEFAULT_BUFFER_SIZE

const val DEFAULT_BUFFER_SIZE: Int = 1024

Default amount of memory to use for bulk operations.

FAST

const val FAST: Float = 0.5f

At most 50% memory overhead, always select a reasonably fast implementation.

FASTEST

const val FASTEST: Float = 7.0f

At most 700% memory overhead, always select a direct implementation.

VERSION_CURRENT

val VERSION_CURRENT: Int

VERSION_MONOTONIC_WITHOUT_ZIGZAG

const val VERSION_MONOTONIC_WITHOUT_ZIGZAG: Int = 2

VERSION_START

val VERSION_START: Int

Functions

bitsRequired

fun bitsRequired(maxValue: Long): Int

Returns how many bits are required to hold values up to and including maxValue NOTE: This method returns at least 1.

checkBlockSize

fun checkBlockSize(blockSize: Int, minBlockSize: Int, maxBlockSize: Int): Int

Check that the block size is a power of 2, in the right bounds, and return its log in base 2.

checkVersion

fun checkVersion(version: Int)

Check the validity of a version number.

copy

fun copy(src: PackedInts.Reader, srcPos: Int, dest: PackedInts.Mutable, destPos: Int, len: Int, mem: Int)

Copy src[srcPos:srcPos+len] into dest[destPos:destPos+len] using at most mem bytes.

fun copy(src: PackedInts.Reader, srcPos: Int, dest: PackedInts.Mutable, destPos: Int, len: Int, buf: LongArray)

Same as .copy but using a pre-allocated buffer.

fastestFormatAndBits

fun fastestFormatAndBits(valueCount: Int, bitsPerValue: Int, acceptableOverheadRatio: Float): PackedInts.FormatAndBits

Try to find the Format and number of bits per value that would restore from disk the fastest reader whose overhead is less than acceptableOverheadRatio.

getDecoder

fun getDecoder(format: PackedInts.Format, version: Int, bitsPerValue: Int): PackedInts.Decoder

Get a Decoder.

getEncoder

fun getEncoder(format: PackedInts.Format, version: Int, bitsPerValue: Int): PackedInts.Encoder

Get an Encoder.

getMutable

fun getMutable(valueCount: Int, bitsPerValue: Int, acceptableOverheadRatio: Float): PackedInts.Mutable

Create a packed integer array with the given amount of values initialized to 0. the valueCount and the bitsPerValue cannot be changed after creation. All Mutables known by this factory are kept fully in RAM.

fun getMutable(valueCount: Int, bitsPerValue: Int, format: PackedInts.Format): PackedInts.Mutable

Same as .getMutable with a pre-computed number of bits per value and format.

getReaderIteratorNoHeader

fun getReaderIteratorNoHeader(in: DataInput, format: PackedInts.Format, version: Int, valueCount: Int, bitsPerValue: Int, mem: Int): PackedInts.ReaderIterator

Expert: Restore a ReaderIterator from a stream without reading metadata at the beginning of the stream. This method is useful to restore data from streams which have been created using PackedInts.getWriterNoHeader.

getWriterNoHeader

fun getWriterNoHeader(out: DataOutput, format: PackedInts.Format, valueCount: Int, bitsPerValue: Int, mem: Int): PackedInts.Writer

Expert: Create a packed integer array writer for the given output, format, value count, and number of bits per value.

maxValue

fun maxValue(bitsPerValue: Int): Long

Calculates the maximum unsigned long that can be expressed with the given number of bits.

numBlocks

fun numBlocks(size: Long, blockSize: Int): Int

Return the number of blocks required to store size values on blockSize * .

unsignedBitsRequired

fun unsignedBitsRequired(bits: Long): Int

Returns how many bits are required to store bits, interpreted as an unsigned value. NOTE: This method returns at least 1.