com.oracle.truffle.regex

Class RegexProfile

java.lang.Object

com.oracle.truffle.regex.RegexProfile

public final class RegexProfile
extends Object

This profile is used for tracking statistics about a compiled regular expression, such as the amount of times the expression was executed and the amount of matches that were found. The profiling information is used by TRegex for deciding whether a regular expression should match capture groups in a lazy or eager way.

See Also:

TRegexExecRootNode, TRegexLazyCaptureGroupsRootNode

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RegexProfile.TracksRegexProfile

Constructor Summary

Constructors

Constructor and Description
RegexProfile()

Method Summary

Modifier and Type	Method and Description
boolean	atEvaluationTripPoint() Check if the profiling information gathered so far is sufficient for making a decision.
void	incCalls() Increase the number of times the regular expression was executed by one.
void	incMatches() Increase the number of times a match for the regular expression was found by one.
void	profileCaptureGroupAccess(int matchLength, int numberOfCharsTraversed) Update profile after the execution of a lazy capture groups search DFA.
void	resetCalls()
boolean	shouldGenerateDFA() Decides whether the regular expression was executed often enough to warrant the costly generation of a fully expanded DFA.
boolean	shouldUseEagerMatching() Decides whether the capture groups of the regular expression should be matched in an eager manner.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

RegexProfile

public RegexProfile()

Method Detail

incCalls

public void incCalls()

Increase the number of times the regular expression was executed by one.

resetCalls

public void resetCalls()

incMatches

public void incMatches()

Increase the number of times a match for the regular expression was found by one.

profileCaptureGroupAccess

public void profileCaptureGroupAccess(int matchLength,
                                      int numberOfCharsTraversed)

Update profile after the execution of a lazy capture groups search DFA.

Parameters:

matchLength - the length of capture group 0 of the match.

numberOfCharsTraversed - the number of characters that were traversed between the initial index (fromIndex) and the end of the match.

See Also:

TRegexLazyCaptureGroupsRootNode

atEvaluationTripPoint

public boolean atEvaluationTripPoint()

Check if the profiling information gathered so far is sufficient for making a decision.

Returns:

true if the number of times the regular expression was called is divisible by .

shouldGenerateDFA

public boolean shouldGenerateDFA()

Decides whether the regular expression was executed often enough to warrant the costly generation of a fully expanded DFA.

shouldUseEagerMatching

public boolean shouldUseEagerMatching()

Decides whether the capture groups of the regular expression should be matched in an eager manner.

Returns:

true if:

• most searches led to a match
• the capture groups of most search results were queried
• the match often covered a big part of the part of the input string that had to be traversed in order to find it.

toString

public String toString()

Overrides:

toString in class Object