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.

This is a Lucene.NET EXPERIMENTAL API, use at your own risk
Inheritance
System.Object
FST<T>
Namespace: Lucene.Net.Util.Fst
Assembly: Lucene.Net.dll
Syntax
public sealed class FST<T> : object
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(FileInfo)

Writes an automaton to a file.

Declaration
public void Save(FileInfo file)
Parameters
Type Name Description
FileInfo file
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Save(DataOutput)

Declaration
public void Save(DataOutput out)
Parameters
Type Name Description
DataOutput out
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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