Class FST<T>

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

The format is similar to what's used by Morfologik (http://sourceforge.net/projects/morfologik).

See the FST package documentation for some simple examples.

Note

This API is experimental and might change in incompatible ways in the next release.

Inheritance

System.Object

FST<T>

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Lucene.Net.Util.Fst

Assembly: Lucene.Net.dll

Syntax

public sealed class FST<T>
    where T : class

Type Parameters

Name	Description
T

Constructors

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FST(DataInput, Outputs<T>)

Load a previously saved FST.

Declaration

public FST(DataInput in, Outputs<T> outputs)

Parameters

Type	Name	Description
DataInput	in
Outputs<T>	outputs

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FST(DataInput, Outputs<T>, Int32)

Load a previously saved FST; maxBlockBits allows you to control the size of the byte[] pages used to hold the FST bytes.

Declaration

public FST(DataInput in, Outputs<T> outputs, int maxBlockBits)

Parameters

Type	Name	Description
DataInput	in
Outputs<T>	outputs
System.Int32	maxBlockBits

Properties

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ArcCount

Declaration

public long ArcCount { get; }

Property Value

Type	Description
System.Int64

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ArcWithOutputCount

Declaration

public long ArcWithOutputCount { get; }

Property Value

Type	Description
System.Int64

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EmptyOutput

Declaration

public T EmptyOutput { get; set; }

Property Value

Type	Description
T

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InputType

Declaration

public FST.INPUT_TYPE InputType { get; }

Property Value

Type	Description
FST.INPUT_TYPE

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NodeCount

Declaration

public long NodeCount { get; }

Property Value

Type	Description
System.Int64

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Outputs

Declaration

public Outputs<T> Outputs { get; }

Property Value

Type	Description
Outputs<T>

Methods

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FindTargetArc(Int32, FST.Arc<T>, FST.Arc<T>, FST.BytesReader)

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.

Declaration

public FST.Arc<T> FindTargetArc(int labelToMatch, FST.Arc<T> follow, FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
System.Int32	labelToMatch
FST.Arc<T>	follow
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>

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GetBytesReader()

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

Declaration

public FST.BytesReader GetBytesReader()

Returns

Type	Description
FST.BytesReader

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GetFirstArc(FST.Arc<T>)

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

Declaration

public FST.Arc<T> GetFirstArc(FST.Arc<T> arc)

Parameters

Type	Name	Description
FST.Arc<T>	arc

Returns

Type	Description
FST.Arc<T>

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GetSizeInBytes()

Returns bytes used to represent the FST

Declaration

public long GetSizeInBytes()

Returns

Type	Description
System.Int64

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ReadFirstRealTargetArc(Int64, FST.Arc<T>, FST.BytesReader)

Declaration

public FST.Arc<T> ReadFirstRealTargetArc(long node, FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
System.Int64	node
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>

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ReadFirstTargetArc(FST.Arc<T>, FST.Arc<T>, FST.BytesReader)

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

Declaration

public FST.Arc<T> ReadFirstTargetArc(FST.Arc<T> follow, FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
FST.Arc<T>	follow
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>	Returns the second argument (`arc`).

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ReadLastTargetArc(FST.Arc<T>, FST.Arc<T>, FST.BytesReader)

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

Declaration

public FST.Arc<T> ReadLastTargetArc(FST.Arc<T> follow, FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
FST.Arc<T>	follow
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>	Returns the second argument (`arc`).

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ReadNextArc(FST.Arc<T>, FST.BytesReader)

In-place read; returns the arc.

Declaration

public FST.Arc<T> ReadNextArc(FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>

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ReadNextArcLabel(FST.Arc<T>, FST.BytesReader)

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

Declaration

public int ReadNextArcLabel(FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
System.Int32

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ReadNextRealArc(FST.Arc<T>, FST.BytesReader)

Never returns null, but you should never call this if arc.IsLast is true.

Declaration

public FST.Arc<T> ReadNextRealArc(FST.Arc<T> arc, FST.BytesReader in)

Parameters

Type	Name	Description
FST.Arc<T>	arc
FST.BytesReader	in

Returns

Type	Description
FST.Arc<T>

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ReadRootArcs(FST.Arc<T>[])

Declaration

public void ReadRootArcs(FST.Arc<T>[] arcs)

Parameters

Type	Name	Description
FST.Arc<T>[]	arcs

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Save(DataOutput)

Declaration

public void Save(DataOutput out)

Parameters

Type	Name	Description
DataOutput	out

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Save(FileInfo)

Writes an automaton to a file.

Declaration

public void Save(FileInfo file)

Parameters

Type	Name	Description
System.IO.FileInfo	file

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TargetHasArcs(FST.Arc<T>)

returns true if the node at this address has any outgoing arcs

Declaration

public static bool TargetHasArcs(FST.Arc<T> arc)

Parameters

Type	Name	Description
FST.Arc<T>	arc

Returns

Type	Description
System.Boolean