Namespace Lucene.Net.Util.Fst

Misc FST classes.

Classes

ListOfOutputs<T>

Wraps another Outputs implementation and encodes one or more of its output values. You can use this when a single input may need to map to more than one output, maintaining order: pass the same input with a different output by calling Lucene.Net.Util.Fst.Builder<T>.Add(Lucene.Net.Util.Int32sRef, T) multiple times. The builder will then combine the outputs using the Lucene.Net.Util.Fst.Outputs<T>.Merge(T, T) method.

The resulting FST may not be minimal when an input has more than one output, as this requires pushing all multi-output values to a final state.

NOTE: the only way to create multiple outputs is to add the same input to the FST multiple times in a row. This is how the FST maps a single input to multiple outputs (e.g. you cannot pass a List<Object> to Lucene.Net.Util.Fst.Builder<T>.Add(Lucene.Net.Util.Int32sRef, T)). If your outputs are longs, and you need at most 2, then use UpToTwoPositiveInt64Outputs instead since it stores the outputs more compactly (by stealing a bit from each long value).

NOTE: this cannot wrap itself (ie you cannot make an FST with List<List<Object>> outputs using this).

Note

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

UpToTwoPositiveInt64Outputs

An FST Lucene.Net.Util.Fst.Outputs<T> implementation where each output is one or two non-negative long values. If it's a float output, Nullable<T> is returned; else, UpToTwoPositiveInt64Outputs.TwoInt64s. Order is preserved in the UpToTwoPositiveInt64Outputs.TwoInt64s case, ie .first is the first input/output added to Lucene.Net.Util.Fst.Builder<T>, and .second is the second. You cannot store 0 output with this (that's reserved to mean "no output")!

NOTE: the only way to create a TwoLongs output is to add the same input to the FST twice in a row. This is how the FST maps a single input to two outputs (e.g. you cannot pass a UpToTwoPositiveInt64Outputs.TwoInt64s to Lucene.Net.Util.Fst.Builder<T>.Add(Lucene.Net.Util.Int32sRef, T). If you need more than two then use ListOfOutputs<T>, but if you only have at most 2 then this implementation will require fewer bytes as it steals one bit from each long value.

NOTE: the resulting FST is not guaranteed to be minimal! See Lucene.Net.Util.Fst.Builder<T>.

NOTE: This was UpToTwoPositiveIntOutputs in Lucene - the data type (int) was wrong there - it should have been long

Note

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

UpToTwoPositiveInt64Outputs.TwoInt64s

Holds two long outputs.

NOTE: This was TwoLongs in Lucene