core/org.gnit.lucenekmp.util.fst/FST

FST

class FST<T> : Accountable

Represents an finite state machine (FST), using a compact byte[] format.

The format is similar to what's used by Morfologik (https://github.com/morfologik/morfologik-stemming).

See the package documentation for some simple examples.

Constructors

constructor(metadata: FST.FSTMetadata<T>, in: DataInput)

Load a previously saved FST with a DataInput for metdata using an OnHeapFSTStore with maxBlockBits set to .DEFAULT_MAX_BLOCK_BITS

Types

class Arc<T>

Represents a single arc.

abstract class BytesReader : DataInput

Reads bytes stored in an FST.

object Companion

class FSTMetadata<T>(val inputType: FST.INPUT_TYPE, val outputs: Outputs<T>, var emptyOutput: T?, startNode: Long, version: Int, numBytes: Long)

Represents the FST metadata.

enum INPUT_TYPE : Enum<FST.INPUT_TYPE>

Specifies allowed range of each int input label for this FST.

Properties

open val childResources: MutableCollection<Accountable>

Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).

val metadata: FST.FSTMetadata<T>

val outputs: Outputs<T>

Functions

fun findTargetArc(labelToMatch: Int, follow: FST.Arc<T>, arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>?

Finds an arc leaving the incoming arc, replacing the arc in place. This returns null if the arc was not found, else the incoming arc.

fun getBytesReader(): FST.BytesReader

Returns a BytesReader for this FST, positioned at position 0.

fun getEmptyOutput(): T?

fun getFirstArc(arc: FST.Arc<T>): FST.Arc<T>

Fills virtual 'start' arc, ie, an empty incoming arc to the FST's start node

isExpandedTarget

fun isExpandedTarget(follow: FST.Arc<T>, in: FST.BytesReader): Boolean

Returns whether arc's target points to a node in expanded format (fixed length arcs).

fun numBytes(): Long

open override fun ramBytesUsed(): Long

Return the memory usage of this object in bytes. Negative values are illegal.

readArcByContinuous

fun readArcByContinuous(arc: FST.Arc<T>, in: FST.BytesReader, rangeIndex: Int): FST.Arc<T>

Reads a Continuous node arc, with the provided index in the label range.

readArcByDirectAddressing

fun readArcByDirectAddressing(arc: FST.Arc<T>, in: FST.BytesReader, rangeIndex: Int): FST.Arc<T>

Reads a present direct addressing node arc, with the provided index in the label range.

fun readArcByIndex(arc: FST.Arc<T>, in: FST.BytesReader, idx: Int): FST.Arc<T>

readFirstRealTargetArc

fun readFirstRealTargetArc(nodeAddress: Long, arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

readFirstTargetArc

fun readFirstTargetArc(follow: FST.Arc<T>, arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

Follow the follow arc and read the first arc of its target; this changes the provided arc (2nd arg) in-place and returns it.

fun readLabel(in: DataInput): Int

Reads one BYTE1/2/4 label from the provided DataInput.

readLastArcByContinuous

fun readLastArcByContinuous(arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

Reads the last arc of a continuous node.

readLastArcByDirectAddressing

fun readLastArcByDirectAddressing(arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

Reads the last arc of a direct addressing node. This method is equivalent to call .readArcByDirectAddressing with rangeIndex equal to arc.numArcs() - 1, but it is faster.

readLastTargetArc

fun readLastTargetArc(follow: FST.Arc<T>, arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

Follows the follow arc and reads the last arc of its target; this changes the provided arc (2nd arg) in-place and returns it.

fun readNextArc(arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

In-place read; returns the arc.

readNextArcLabel

fun readNextArcLabel(arc: FST.Arc<T>, in: FST.BytesReader): Int

Peeks at next arc's label; does not alter arc. Do not call this if arc.isLast()!

readNextRealArc

fun readNextRealArc(arc: FST.Arc<T>, in: FST.BytesReader): FST.Arc<T>

Never returns null, but you should never call this if arc.isLast() is true.

fun save(path: Path)

Writes an automaton to a file.

fun save(metaOut: DataOutput, out: DataOutput)

Save the FST to DataOutput.

open override fun toString(): String