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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.common.regex;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.automaton.Automata;
import org.apache.lucene.util.automaton.Automaton;
import org.apache.lucene.util.automaton.CharacterRunAutomaton;
import org.apache.lucene.util.automaton.Operations;
import org.elasticsearch.common.Strings;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import java.util.function.Predicate;
import java.util.regex.Pattern;
public class Regex {
/**
* This Regex / {@link Pattern} flag is supported from Java 7 on.
* If set on a Java6 JVM the flag will be ignored.
*/
public static final int UNICODE_CHARACTER_CLASS = 0x100; // supported in JAVA7
/**
* Is the str a simple match pattern.
*/
public static boolean isSimpleMatchPattern(String str) {
return str.indexOf('*') != -1;
}
public static boolean isMatchAllPattern(String str) {
return str.equals("*");
}
public static boolean isSuffixMatchPattern(String str) {
return str.length() > 1 && str.indexOf("*") == str.length() - 1;
}
/** Return an {@link Automaton} that matches the given pattern. */
public static Automaton simpleMatchToAutomaton(String pattern) {
List automata = new ArrayList<>();
int previous = 0;
for (int i = pattern.indexOf('*'); i != -1; i = pattern.indexOf('*', i + 1)) {
automata.add(Automata.makeString(pattern.substring(previous, i)));
automata.add(Automata.makeAnyString());
previous = i + 1;
}
automata.add(Automata.makeString(pattern.substring(previous)));
return Operations.concatenate(automata);
}
/**
* Return an Automaton that matches the union of the provided patterns.
*/
public static Automaton simpleMatchToAutomaton(String... patterns) {
if (patterns.length < 1) {
throw new IllegalArgumentException("There must be at least one pattern, zero given");
}
List simpleStrings = new ArrayList<>();
List automata = new ArrayList<>();
for (String pattern : patterns) {
// Strings longer than 1000 characters aren't supported by makeStringUnion
if (isSimpleMatchPattern(pattern) || pattern.length() >= 1000) {
automata.add(simpleMatchToAutomaton(pattern));
} else {
simpleStrings.add(new BytesRef(pattern));
}
}
if (false == simpleStrings.isEmpty()) {
Automaton simpleStringsAutomaton;
if (simpleStrings.size() > 0) {
Collections.sort(simpleStrings);
simpleStringsAutomaton = Automata.makeStringUnion(simpleStrings);
} else {
simpleStringsAutomaton = Automata.makeString(simpleStrings.get(0).utf8ToString());
}
if (automata.isEmpty()) {
return simpleStringsAutomaton;
}
automata.add(simpleStringsAutomaton);
}
return Operations.union(automata);
}
/**
* Create a {@link Predicate} that matches the given patterns. Evaluating
* the returned predicate against a {@link String} yields the same result as
* running {@link #simpleMatch(String[], String)} but may run faster,
* especially in the case when there are multiple patterns.
*/
public static Predicate simpleMatcher(String... patterns) {
if (patterns == null || patterns.length == 0) {
return str -> false;
}
boolean hasWildcard = false;
for (String pattern : patterns) {
if (isMatchAllPattern(pattern)) {
return str -> true;
}
if (isSimpleMatchPattern(pattern)) {
hasWildcard = true;
break;
}
}
if (patterns.length == 1) {
if (hasWildcard) {
return str -> simpleMatch(patterns[0], str);
} else {
return patterns[0]::equals;
}
} else if (hasWildcard == false) {
return Set.copyOf(Arrays.asList(patterns))::contains;
} else {
Automaton automaton = simpleMatchToAutomaton(patterns);
return new CharacterRunAutomaton(automaton)::run;
}
}
/**
* Match a String against the given pattern, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
* Matching is case sensitive.
*
* @param pattern the pattern to match against
* @param str the String to match
* @return whether the String matches the given pattern
*/
public static boolean simpleMatch(String pattern, String str) {
return simpleMatch(pattern, str, false);
}
/**
* Match a String against the given pattern, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
*
* @param pattern the pattern to match against
* @param str the String to match
* @param caseInsensitive true if ASCII case differences should be ignored
* @return whether the String matches the given pattern
*/
public static boolean simpleMatch(String pattern, String str, boolean caseInsensitive) {
if (pattern == null || str == null) {
return false;
}
if (caseInsensitive) {
pattern = Strings.toLowercaseAscii(pattern);
str = Strings.toLowercaseAscii(str);
}
return simpleMatchWithNormalizedStrings(pattern, str);
}
private static boolean simpleMatchWithNormalizedStrings(String pattern, String str) {
final int firstIndex = pattern.indexOf('*');
if (firstIndex == -1) {
return pattern.equals(str);
}
if (firstIndex == 0) {
if (pattern.length() == 1) {
return true;
}
final int nextIndex = pattern.indexOf('*', firstIndex + 1);
if (nextIndex == -1) {
// str.endsWith(pattern.substring(1)), but avoiding the construction of pattern.substring(1):
return str.regionMatches(str.length() - pattern.length() + 1, pattern, 1, pattern.length() - 1);
} else if (nextIndex == 1) {
// Double wildcard "**" - skipping the first "*"
return simpleMatchWithNormalizedStrings(pattern.substring(1), str);
}
final String part = pattern.substring(1, nextIndex);
int partIndex = str.indexOf(part);
while (partIndex != -1) {
if (simpleMatchWithNormalizedStrings(pattern.substring(nextIndex), str.substring(partIndex + part.length()))) {
return true;
}
partIndex = str.indexOf(part, partIndex + 1);
}
return false;
}
return str.regionMatches(0, pattern, 0, firstIndex)
&& (firstIndex == pattern.length() - 1 // only wildcard in pattern is at the end, so no need to look at the rest of the string
|| simpleMatchWithNormalizedStrings(pattern.substring(firstIndex), str.substring(firstIndex)));
}
/**
* Match a String against the given patterns, supporting the following simple
* pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
* arbitrary number of pattern parts), as well as direct equality.
*
* @param patterns the patterns to match against
* @param str the String to match
* @return whether the String matches any of the given patterns
*/
public static boolean simpleMatch(String[] patterns, String str) {
if (patterns != null) {
for (String pattern : patterns) {
if (simpleMatch(pattern, str)) {
return true;
}
}
}
return false;
}
/**
* Similar to {@link #simpleMatch(String[], String)}, but accepts a list of strings instead of an array of strings for the patterns to
* match.
*/
public static boolean simpleMatch(final List patterns, final String str) {
// #simpleMatch(String[], String) is likely to be inlined into this method
return patterns != null && simpleMatch(patterns.toArray(Strings.EMPTY_ARRAY), str);
}
public static Pattern compile(String regex, String flags) {
int pFlags = flags == null ? 0 : flagsFromString(flags);
return Pattern.compile(regex, pFlags);
}
public static int flagsFromString(String flags) {
int pFlags = 0;
for (String s : Strings.delimitedListToStringArray(flags, "|")) {
if (s.isEmpty()) {
continue;
}
s = s.toUpperCase(Locale.ROOT);
if ("CASE_INSENSITIVE".equals(s)) {
pFlags |= Pattern.CASE_INSENSITIVE;
} else if ("MULTILINE".equals(s)) {
pFlags |= Pattern.MULTILINE;
} else if ("DOTALL".equals(s)) {
pFlags |= Pattern.DOTALL;
} else if ("UNICODE_CASE".equals(s)) {
pFlags |= Pattern.UNICODE_CASE;
} else if ("CANON_EQ".equals(s)) {
pFlags |= Pattern.CANON_EQ;
} else if ("UNIX_LINES".equals(s)) {
pFlags |= Pattern.UNIX_LINES;
} else if ("LITERAL".equals(s)) {
pFlags |= Pattern.LITERAL;
} else if ("COMMENTS".equals(s)) {
pFlags |= Pattern.COMMENTS;
} else if (("UNICODE_CHAR_CLASS".equals(s)) || ("UNICODE_CHARACTER_CLASS".equals(s))) {
pFlags |= UNICODE_CHARACTER_CLASS;
} else {
throw new IllegalArgumentException("Unknown regex flag [" + s + "]");
}
}
return pFlags;
}
public static String flagsToString(int flags) {
StringBuilder sb = new StringBuilder();
if ((flags & Pattern.CASE_INSENSITIVE) != 0) {
sb.append("CASE_INSENSITIVE|");
}
if ((flags & Pattern.MULTILINE) != 0) {
sb.append("MULTILINE|");
}
if ((flags & Pattern.DOTALL) != 0) {
sb.append("DOTALL|");
}
if ((flags & Pattern.UNICODE_CASE) != 0) {
sb.append("UNICODE_CASE|");
}
if ((flags & Pattern.CANON_EQ) != 0) {
sb.append("CANON_EQ|");
}
if ((flags & Pattern.UNIX_LINES) != 0) {
sb.append("UNIX_LINES|");
}
if ((flags & Pattern.LITERAL) != 0) {
sb.append("LITERAL|");
}
if ((flags & Pattern.COMMENTS) != 0) {
sb.append("COMMENTS|");
}
if ((flags & UNICODE_CHARACTER_CLASS) != 0) {
sb.append("UNICODE_CHAR_CLASS|");
}
return sb.toString();
}
}
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