com.oracle.truffle.regex.tregex.automaton

Class StateTransitionCanonicalizer<SI extends StateIndex<? super S>,S extends AbstractState<S,T>,T extends AbstractTransition<S,T>,TB extends TransitionBuilder<SI,S,T>>

java.lang.Object

com.oracle.truffle.regex.tregex.automaton.StateTransitionCanonicalizer<SI,S,T,TB>

Type Parameters:

TB - represents a DFA transition fragment. This type is used for both intermediate and final results.

Direct Known Subclasses:

ASTTransitionCanonicalizer, DFATransitionCanonicalizer

public abstract class StateTransitionCanonicalizer<SI extends StateIndex<? super S>,S extends AbstractState<S,T>,T extends AbstractTransition<S,T>,TB extends TransitionBuilder<SI,S,T>>
extends Object

This class provides an algorithm for converting a list of NFA transitions into a set of DFA transitions.

See Also:

TransitionBuilder, TransitionSet

Constructor Summary

Constructors

Constructor and Description
StateTransitionCanonicalizer(SI stateIndex, boolean forward, boolean prioritySensitive)

Method Summary

Modifier and Type	Method and Description
void	addArgument(T transition, CodePointSet charSet) Submits an argument to be processed by StateTransitionCanonicalizer.run(CompilationBuffer).
protected abstract boolean	canMerge(TB a, TB b) Returns true if two DFA transitions are allowed to be merged into one.
protected abstract TB[]	createResultArray(int size) Returns an array suitable for holding the result of StateTransitionCanonicalizer.run(CompilationBuffer).
protected abstract T[]	createTransitionArray(int size)
protected abstract TB	createTransitionBuilder(T[] transitions, StateSet<SI,S> targetStateSet, CodePointSet matcherBuilder)
protected boolean	isPrioritySensitive() If priority-sensitive mode, transition sets are pruned after transitions to final states.
TB[]	run(CompilationBuffer compilationBuffer) Runs the NFA to DFA transition conversion algorithm on the NFA transitions given by previous calls to StateTransitionCanonicalizer.addArgument(AbstractTransition, CodePointSet).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StateTransitionCanonicalizer

public StateTransitionCanonicalizer(SI stateIndex,
                                    boolean forward,
                                    boolean prioritySensitive)

Method Detail

isPrioritySensitive

protected boolean isPrioritySensitive()

If priority-sensitive mode, transition sets are pruned after transitions to final states. Also, target state sets are considered equal iff their order is equal as well.

addArgument

public void addArgument(T transition,
                        CodePointSet charSet)

Submits an argument to be processed by StateTransitionCanonicalizer.run(CompilationBuffer).

run

public TB[] run(CompilationBuffer compilationBuffer)

Runs the NFA to DFA transition conversion algorithm on the NFA transitions given by previous calls to StateTransitionCanonicalizer.addArgument(AbstractTransition, CodePointSet). This algorithm has two phases:

1. Merge NFA transitions according to their expected character sets. The result of this phase is a list of TransitionBuilders whose CodePointSets have no more intersections.
2. Merge TransitionBuilders generated by the first phase if their target state is equal and StateTransitionCanonicalizer.canMerge(TransitionBuilder, TransitionBuilder) returns true.

Returns:

a set of transition builders representing the DFA transitions generated from the given NFA transitions.

createTransitionBuilder

protected abstract TB createTransitionBuilder(T[] transitions,
                                              StateSet<SI,S> targetStateSet,
                                              CodePointSet matcherBuilder)

canMerge

protected abstract boolean canMerge(TB a,
                                    TB b)

Returns true if two DFA transitions are allowed to be merged into one.

createTransitionArray

protected abstract T[] createTransitionArray(int size)

createResultArray

protected abstract TB[] createResultArray(int size)

Returns an array suitable for holding the result of StateTransitionCanonicalizer.run(CompilationBuffer).