Java tutorial
/* * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.util.regex; import java.text.Normalizer; import java.text.Normalizer.Form; import java.util.Locale; import java.util.Iterator; import java.util.Map; import java.util.ArrayList; import java.util.HashMap; import java.util.LinkedHashSet; import java.util.List; import java.util.Set; import java.util.Arrays; import java.util.NoSuchElementException; import java.util.Spliterator; import java.util.Spliterators; import java.util.function.Predicate; import java.util.stream.Stream; import java.util.stream.StreamSupport; import jdk.internal.util.ArraysSupport; /** * A compiled representation of a regular expression. * * <p> A regular expression, specified as a string, must first be compiled into * an instance of this class. The resulting pattern can then be used to create * a {@link Matcher} object that can match arbitrary {@linkplain * java.lang.CharSequence character sequences} against the regular * expression. All of the state involved in performing a match resides in the * matcher, so many matchers can share the same pattern. * * <p> A typical invocation sequence is thus * * <blockquote><pre> * Pattern p = Pattern.{@link #compile compile}("a*b"); * Matcher m = p.{@link #matcher matcher}("aaaaab"); * boolean b = m.{@link Matcher#matches matches}();</pre></blockquote> * * <p> A {@link #matches matches} method is defined by this class as a * convenience for when a regular expression is used just once. This method * compiles an expression and matches an input sequence against it in a single * invocation. The statement * * <blockquote><pre> * boolean b = Pattern.matches("a*b", "aaaaab");</pre></blockquote> * * is equivalent to the three statements above, though for repeated matches it * is less efficient since it does not allow the compiled pattern to be reused. * * <p> Instances of this class are immutable and are safe for use by multiple * concurrent threads. Instances of the {@link Matcher} class are not safe for * such use. * * * <h2><a id="sum">Summary of regular-expression constructs</a></h2> * * <table class="borderless"> * <caption style="display:none">Regular expression constructs, and what they match</caption> * <thead style="text-align:left"> * <tr> * <th id="construct">Construct</th> * <th id="matches">Matches</th> * </tr> * </thead> * <tbody style="text-align:left"> * * <tr><th colspan="2" style="padding-top:20px" id="characters">Characters</th></tr> * * <tr><th style="vertical-align:top; font-weight: normal" id="x"><i>x</i></th> * <td headers="matches characters x">The character <i>x</i></td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="backslash">{@code \\}</th> * <td headers="matches characters backslash">The backslash character</td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="octal_n">{@code \0}<i>n</i></th> * <td headers="matches characters octal_n">The character with octal value {@code 0}<i>n</i> * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nn">{@code \0}<i>nn</i></th> * <td headers="matches characters octal_nn">The character with octal value {@code 0}<i>nn</i> * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nnn">{@code \0}<i>mnn</i></th> * <td headers="matches characters octal_nnn">The character with octal value {@code 0}<i>mnn</i> * (0 {@code <=} <i>m</i> {@code <=} 3, * 0 {@code <=} <i>n</i> {@code <=} 7)</td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hh">{@code \x}<i>hh</i></th> * <td headers="matches characters hex_hh">The character with hexadecimal value {@code 0x}<i>hh</i></td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hhhh"><code>\u</code><i>hhhh</i></th> * <td headers="matches characters hex_hhhh">The character with hexadecimal value {@code 0x}<i>hhhh</i></td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="hex_h_h"><code>\x</code><i>{h...h}</i></th> * <td headers="matches characters hex_h_h">The character with hexadecimal value {@code 0x}<i>h...h</i> * ({@link java.lang.Character#MIN_CODE_POINT Character.MIN_CODE_POINT} * <= {@code 0x}<i>h...h</i> <= * {@link java.lang.Character#MAX_CODE_POINT Character.MAX_CODE_POINT})</td></tr> * <tr><th style="vertical-align:top; font-weight: normal" id="unicode_name"><code>\N{</code><i>name</i><code>}</code></th> * <td headers="matches characters unicode_name">The character with Unicode character name <i>'name'</i></td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="tab">{@code \t}</th> * <td headers="matches characters tab">The tab character (<code>'\u0009'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="newline">{@code \n}</th> * <td headers="matches characters newline">The newline (line feed) character (<code>'\u000A'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="return">{@code \r}</th> * <td headers="matches characters return">The carriage-return character (<code>'\u000D'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="form_feed">{@code \f}</th> * <td headers="matches characters form_feed">The form-feed character (<code>'\u000C'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="bell">{@code \a}</th> * <td headers="matches characters bell">The alert (bell) character (<code>'\u0007'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="escape">{@code \e}</th> * <td headers="matches characters escape">The escape character (<code>'\u001B'</code>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="ctrl_x">{@code \c}<i>x</i></th> * <td headers="matches characters ctrl_x">The control character corresponding to <i>x</i></td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="classes">Character classes</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="simple">{@code [abc]}</th> * <td headers="matches classes simple">{@code a}, {@code b}, or {@code c} (simple class)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="negation">{@code [^abc]}</th> * <td headers="matches classes negation">Any character except {@code a}, {@code b}, or {@code c} (negation)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="range">{@code [a-zA-Z]}</th> * <td headers="matches classes range">{@code a} through {@code z} * or {@code A} through {@code Z}, inclusive (range)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="union">{@code [a-d[m-p]]}</th> * <td headers="matches classes union">{@code a} through {@code d}, * or {@code m} through {@code p}: {@code [a-dm-p]} (union)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="intersection">{@code [a-z&&[def]]}</th> * <td headers="matches classes intersection">{@code d}, {@code e}, or {@code f} (intersection)</tr> * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction1">{@code [a-z&&[^bc]]}</th> * <td headers="matches classes subtraction1">{@code a} through {@code z}, * except for {@code b} and {@code c}: {@code [ad-z]} (subtraction)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction2">{@code [a-z&&[^m-p]]}</th> * <td headers="matches classes subtraction2">{@code a} through {@code z}, * and not {@code m} through {@code p}: {@code [a-lq-z]}(subtraction)</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="predef">Predefined character classes</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="any">{@code .}</th> * <td headers="matches predef any">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="digit">{@code \d}</th> * <td headers="matches predef digit">A digit: {@code [0-9]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_digit">{@code \D}</th> * <td headers="matches predef non_digit">A non-digit: {@code [^0-9]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="horiz_white">{@code \h}</th> * <td headers="matches predef horiz_white">A horizontal whitespace character: * <code>[ \t\xA0\u1680\u180e\u2000-\u200a\u202f\u205f\u3000]</code></td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_horiz_white">{@code \H}</th> * <td headers="matches predef non_horiz_white">A non-horizontal whitespace character: {@code [^\h]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="white">{@code \s}</th> * <td headers="matches predef white">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_white">{@code \S}</th> * <td headers="matches predef non_white">A non-whitespace character: {@code [^\s]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="vert_white">{@code \v}</th> * <td headers="matches predef vert_white">A vertical whitespace character: <code>[\n\x0B\f\r\x85\u2028\u2029]</code> * </td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_vert_white">{@code \V}</th> * <td headers="matches predef non_vert_white">A non-vertical whitespace character: {@code [^\v]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="word">{@code \w}</th> * <td headers="matches predef word">A word character: {@code [a-zA-Z_0-9]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_word">{@code \W}</th> * <td headers="matches predef non_word">A non-word character: {@code [^\w]}</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="posix"><b>POSIX character classes (US-ASCII only)</b></th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="Lower">{@code \p{Lower}}</th> * <td headers="matches posix Lower">A lower-case alphabetic character: {@code [a-z]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Upper">{@code \p{Upper}}</th> * <td headers="matches posix Upper">An upper-case alphabetic character:{@code [A-Z]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="ASCII">{@code \p{ASCII}}</th> * <td headers="matches posix ASCII">All ASCII:{@code [\x00-\x7F]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Alpha">{@code \p{Alpha}}</th> * <td headers="matches posix Alpha">An alphabetic character:{@code [\p{Lower}\p{Upper}]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Digit">{@code \p{Digit}}</th> * <td headers="matches posix Digit">A decimal digit: {@code [0-9]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Alnum">{@code \p{Alnum}}</th> * <td headers="matches posix Alnum">An alphanumeric character:{@code [\p{Alpha}\p{Digit}]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Punct">{@code \p{Punct}}</th> * <td headers="matches posix Punct">Punctuation: One of {@code !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~}</td></tr> * <!-- {@code [\!"#\$%&'\(\)\*\+,\-\./:;\<=\>\?@\[\\\]\^_`\{\|\}~]} * {@code [\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]} --> * <tr><th style="vertical-align:top; font-weight:normal" id="Graph">{@code \p{Graph}}</th> * <td headers="matches posix Graph">A visible character: {@code [\p{Alnum}\p{Punct}]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Print">{@code \p{Print}}</th> * <td headers="matches posix Print">A printable character: {@code [\p{Graph}\x20]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Blank">{@code \p{Blank}}</th> * <td headers="matches posix Blank">A space or a tab: {@code [ \t]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Cntrl">{@code \p{Cntrl}}</th> * <td headers="matches posix Cntrl">A control character: {@code [\x00-\x1F\x7F]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="XDigit">{@code \p{XDigit}}</th> * <td headers="matches posix XDigit">A hexadecimal digit: {@code [0-9a-fA-F]}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Space">{@code \p{Space}}</th> * <td headers="matches posix Space">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="java">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="javaLowerCase">{@code \p{javaLowerCase}}</th> * <td headers="matches java javaLowerCase">Equivalent to java.lang.Character.isLowerCase()</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="javaUpperCase">{@code \p{javaUpperCase}}</th> * <td headers="matches java javaUpperCase">Equivalent to java.lang.Character.isUpperCase()</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="javaWhitespace">{@code \p{javaWhitespace}}</th> * <td headers="matches java javaWhitespace">Equivalent to java.lang.Character.isWhitespace()</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="javaMirrored">{@code \p{javaMirrored}}</th> * <td headers="matches java javaMirrored">Equivalent to java.lang.Character.isMirrored()</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="unicode">Classes for Unicode scripts, blocks, categories and binary properties</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="IsLatin">{@code \p{IsLatin}}</th> * <td headers="matches unicode IsLatin">A Latin script character (<a href="#usc">script</a>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="InGreek">{@code \p{InGreek}}</th> * <td headers="matches unicode InGreek">A character in the Greek block (<a href="#ubc">block</a>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Lu">{@code \p{Lu}}</th> * <td headers="matches unicode Lu">An uppercase letter (<a href="#ucc">category</a>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="IsAlphabetic">{@code \p{IsAlphabetic}}</th> * <td headers="matches unicode IsAlphabetic">An alphabetic character (<a href="#ubpc">binary property</a>)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="Sc">{@code \p{Sc}}</th> * <td headers="matches unicode Sc">A currency symbol</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="not_InGreek">{@code \P{InGreek}}</th> * <td headers="matches unicode not_InGreek">Any character except one in the Greek block (negation)</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="not_uppercase">{@code [\p{L}&&[^\p{Lu}]]}</th> * <td headers="matches unicode not_uppercase">Any letter except an uppercase letter (subtraction)</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="bounds">Boundary matchers</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="begin_line">{@code ^}</th> * <td headers="matches bounds begin_line">The beginning of a line</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="end_line">{@code $}</th> * <td headers="matches bounds end_line">The end of a line</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="word_boundary">{@code \b}</th> * <td headers="matches bounds word_boundary">A word boundary</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_cluster_boundary">{@code \b{g}}</th> * <td headers="matches bounds grapheme_cluster_boundary">A Unicode extended grapheme cluster boundary</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_word_boundary">{@code \B}</th> * <td headers="matches bounds non_word_boundary">A non-word boundary</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="begin_input">{@code \A}</th> * <td headers="matches bounds begin_input">The beginning of the input</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="end_prev_match">{@code \G}</th> * <td headers="matches bounds end_prev_match">The end of the previous match</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="end_input_except_term">{@code \Z}</th> * <td headers="matches bounds end_input_except_term">The end of the input but for the final * <a href="#lt">terminator</a>, if any</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="end_input">{@code \z}</th> * <td headers="matches bounds end_input">The end of the input</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="linebreak">Linebreak matcher</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="any_unicode_linebreak">{@code \R}</th> * <td headers="matches linebreak any_unicode_linebreak">Any Unicode linebreak sequence, is equivalent to * <code>\u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029] * </code></td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="grapheme">Unicode Extended Grapheme matcher</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_any">{@code \X}</th> * <td headers="matches grapheme grapheme_any">Any Unicode extended grapheme cluster</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="greedy">Greedy quantifiers</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_once_or_not"><i>X</i>{@code ?}</th> * <td headers="matches greedy greedy_once_or_not"><i>X</i>, once or not at all</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_zero_or_more"><i>X</i>{@code *}</th> * <td headers="matches greedy greedy_zero_or_more"><i>X</i>, zero or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_one_or_more"><i>X</i>{@code +}</th> * <td headers="matches greedy greedy_one_or_more"><i>X</i>, one or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_exactly"><i>X</i><code>{</code><i>n</i><code>}</code></th> * <td headers="matches greedy greedy_exactly"><i>X</i>, exactly <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least"><i>X</i><code>{</code><i>n</i>{@code ,}}</th> * <td headers="matches greedy greedy_at_least"><i>X</i>, at least <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}</code></th> * <td headers="matches greedy greedy_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="reluc">Reluctant quantifiers</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_once_or_not"><i>X</i>{@code ??}</th> * <td headers="matches reluc reluc_once_or_not"><i>X</i>, once or not at all</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_zero_or_more"><i>X</i>{@code *?}</th> * <td headers="matches reluc reluc_zero_or_more"><i>X</i>, zero or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_one_or_more"><i>X</i>{@code +?}</th> * <td headers="matches reluc reluc_one_or_more"><i>X</i>, one or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_exactly"><i>X</i><code>{</code><i>n</i><code>}?</code></th> * <td headers="matches reluc reluc_exactly"><i>X</i>, exactly <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least"><i>X</i><code>{</code><i>n</i><code>,}?</code></th> * <td headers="matches reluc reluc_at_least"><i>X</i>, at least <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}?</code></th> * <td headers="matches reluc reluc_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="poss">Possessive quantifiers</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="poss_once_or_not"><i>X</i>{@code ?+}</th> * <td headers="matches poss poss_once_or_not"><i>X</i>, once or not at all</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="poss_zero_or_more"><i>X</i>{@code *+}</th> * <td headers="matches poss poss_zero_or_more"><i>X</i>, zero or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="poss_one_or_more"><i>X</i>{@code ++}</th> * <td headers="matches poss poss_one_or_more"><i>X</i>, one or more times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="poss_exactly"><i>X</i><code>{</code><i>n</i><code>}+</code></th> * <td headers="matches poss poss_exactly"><i>X</i>, exactly <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least"><i>X</i><code>{</code><i>n</i><code>,}+</code></th> * <td headers="matches poss poss_at_least"><i>X</i>, at least <i>n</i> times</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}+</code></th> * <td headers="matches poss poss_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="logical">Logical operators</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="concat"><i>XY</i></th> * <td headers="matches logical concat"><i>X</i> followed by <i>Y</i></td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="alternate"><i>X</i>{@code |}<i>Y</i></th> * <td headers="matches logical alternate">Either <i>X</i> or <i>Y</i></td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="group">{@code (}<i>X</i>{@code )}</th> * <td headers="matches logical group">X, as a <a href="#cg">capturing group</a></td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="backref">Back references</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="back_nth">{@code \}<i>n</i></th> * <td headers="matches backref back_nth">Whatever the <i>n</i><sup>th</sup> * <a href="#cg">capturing group</a> matched</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="back_named">{@code \}<i>k</i><<i>name</i>></th> * <td headers="matches backref back_named">Whatever the * <a href="#groupname">named-capturing group</a> "name" matched</td></tr> * * <tr><th colspan="2" style="padding-top:20px" id="quote">Quotation</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="quote_follow">{@code \}</th> * <td headers="matches quote quote_follow">Nothing, but quotes the following character</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="quote_begin">{@code \Q}</th> * <td headers="matches quote quote_begin">Nothing, but quotes all characters until {@code \E}</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="quote_end">{@code \E}</th> * <td headers="matches quote quote_end">Nothing, but ends quoting started by {@code \Q}</td></tr> * <!-- Metachars: !$()*+.<>?[\]^{|} --> * * <tr><th colspan="2" style="padding-top:20px" id="special">Special constructs (named-capturing and non-capturing)</th></tr> * * <tr><th style="vertical-align:top; font-weight:normal" id="named_group"><code>(?<<a href="#groupname">name</a>></code><i>X</i>{@code )}</th> * <td headers="matches special named_group"><i>X</i>, as a named-capturing group</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group">{@code (?:}<i>X</i>{@code )}</th> * <td headers="matches special non_capture_group"><i>X</i>, as a non-capturing group</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="flags"><code>(?idmsuxU-idmsuxU) </code></th> * <td headers="matches special flags">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a> * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> <a href="#UNICODE_CHARACTER_CLASS">U</a> * on - off</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group_flags"><code>(?idmsux-idmsux:</code><i>X</i>{@code )} </th> * <td headers="matches special non_capture_group_flags"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a> * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a > * <a href="#COMMENTS">x</a> on - off</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookahead">{@code (?=}<i>X</i>{@code )}</th> * <td headers="matches special pos_lookahead"><i>X</i>, via zero-width positive lookahead</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookahead">{@code (?!}<i>X</i>{@code )}</th> * <td headers="matches special neg_lookahead"><i>X</i>, via zero-width negative lookahead</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookbehind">{@code (?<=}<i>X</i>{@code )}</th> * <td headers="matches special pos_lookbehind"><i>X</i>, via zero-width positive lookbehind</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookbehind">{@code (?<!}<i>X</i>{@code )}</th> * <td headers="matches special neg_lookbehind"><i>X</i>, via zero-width negative lookbehind</td></tr> * <tr><th style="vertical-align:top; font-weight:normal" id="indep_non_capture_group">{@code (?>}<i>X</i>{@code )}</th> * <td headers="matches special indep_non_capture_group"><i>X</i>, as an independent, non-capturing group</td></tr> * * </tbody> * </table> * * <hr> * * * <h2><a id="bs">Backslashes, escapes, and quoting</a></h2> * * <p> The backslash character ({@code '\'}) serves to introduce escaped * constructs, as defined in the table above, as well as to quote characters * that otherwise would be interpreted as unescaped constructs. Thus the * expression {@code \\} matches a single backslash and <code>\{</code> matches a * left brace. * * <p> It is an error to use a backslash prior to any alphabetic character that * does not denote an escaped construct; these are reserved for future * extensions to the regular-expression language. A backslash may be used * prior to a non-alphabetic character regardless of whether that character is * part of an unescaped construct. * * <p> Backslashes within string literals in Java source code are interpreted * as required by * <cite>The Java™ Language Specification</cite> * as either Unicode escapes (section 3.3) or other character escapes (section 3.10.6) * It is therefore necessary to double backslashes in string * literals that represent regular expressions to protect them from * interpretation by the Java bytecode compiler. The string literal * <code>"\b"</code>, for example, matches a single backspace character when * interpreted as a regular expression, while {@code "\\b"} matches a * word boundary. The string literal {@code "\(hello\)"} is illegal * and leads to a compile-time error; in order to match the string * {@code (hello)} the string literal {@code "\\(hello\\)"} * must be used. * * <h2><a id="cc">Character Classes</a></h2> * * <p> Character classes may appear within other character classes, and * may be composed by the union operator (implicit) and the intersection * operator ({@code &&}). * The union operator denotes a class that contains every character that is * in at least one of its operand classes. The intersection operator * denotes a class that contains every character that is in both of its * operand classes. * * <p> The precedence of character-class operators is as follows, from * highest to lowest: * * <table class="striped" style="margin-left: 2em;"> * <caption style="display:none">Precedence of character class operators.</caption> * <thead> * <tr><th scope="col">Precedence<th scope="col">Name<th scope="col">Example * </thead> * <tbody> * <tr><th scope="row">1</th> * <td>Literal escape </td> * <td>{@code \x}</td></tr> * <tr><th scope="row">2</th> * <td>Grouping</td> * <td>{@code [...]}</td></tr> * <tr><th scope="row">3</th> * <td>Range</td> * <td>{@code a-z}</td></tr> * <tr><th scope="row">4</th> * <td>Union</td> * <td>{@code [a-e][i-u]}</td></tr> * <tr><th scope="row">5</th> * <td>Intersection</td> * <td>{@code [a-z&&[aeiou]]}</td></tr> * </tbody> * </table> * * <p> Note that a different set of metacharacters are in effect inside * a character class than outside a character class. For instance, the * regular expression {@code .} loses its special meaning inside a * character class, while the expression {@code -} becomes a range * forming metacharacter. * * <h2><a id="lt">Line terminators</a></h2> * * <p> A <i>line terminator</i> is a one- or two-character sequence that marks * the end of a line of the input character sequence. The following are * recognized as line terminators: * * <ul> * * <li> A newline (line feed) character ({@code '\n'}), * * <li> A carriage-return character followed immediately by a newline * character ({@code "\r\n"}), * * <li> A standalone carriage-return character ({@code '\r'}), * * <li> A next-line character (<code>'\u0085'</code>), * * <li> A line-separator character (<code>'\u2028'</code>), or * * <li> A paragraph-separator character (<code>'\u2029'</code>). * * </ul> * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators * recognized are newline characters. * * <p> The regular expression {@code .} matches any character except a line * terminator unless the {@link #DOTALL} flag is specified. * * <p> By default, the regular expressions {@code ^} and {@code $} ignore * line terminators and only match at the beginning and the end, respectively, * of the entire input sequence. If {@link #MULTILINE} mode is activated then * {@code ^} matches at the beginning of input and after any line terminator * except at the end of input. When in {@link #MULTILINE} mode {@code $} * matches just before a line terminator or the end of the input sequence. * * <h2><a id="cg">Groups and capturing</a></h2> * * <h3><a id="gnumber">Group number</a></h3> * <p> Capturing groups are numbered by counting their opening parentheses from * left to right. In the expression {@code ((A)(B(C)))}, for example, there * are four such groups: </p> * * <ol style="margin-left:2em;"> * <li> {@code ((A)(B(C)))} * <li> {@code (A)} * <li> {@code (B(C))} * <li> {@code (C)} * </ol> * * <p> Group zero always stands for the entire expression. * * <p> Capturing groups are so named because, during a match, each subsequence * of the input sequence that matches such a group is saved. The captured * subsequence may be used later in the expression, via a back reference, and * may also be retrieved from the matcher once the match operation is complete. * * <h3><a id="groupname">Group name</a></h3> * <p>A capturing group can also be assigned a "name", a {@code named-capturing group}, * and then be back-referenced later by the "name". Group names are composed of * the following characters. The first character must be a {@code letter}. * * <ul> * <li> The uppercase letters {@code 'A'} through {@code 'Z'} * (<code>'\u0041'</code> through <code>'\u005a'</code>), * <li> The lowercase letters {@code 'a'} through {@code 'z'} * (<code>'\u0061'</code> through <code>'\u007a'</code>), * <li> The digits {@code '0'} through {@code '9'} * (<code>'\u0030'</code> through <code>'\u0039'</code>), * </ul> * * <p> A {@code named-capturing group} is still numbered as described in * <a href="#gnumber">Group number</a>. * * <p> The captured input associated with a group is always the subsequence * that the group most recently matched. If a group is evaluated a second time * because of quantification then its previously-captured value, if any, will * be retained if the second evaluation fails. Matching the string * {@code "aba"} against the expression {@code (a(b)?)+}, for example, leaves * group two set to {@code "b"}. All captured input is discarded at the * beginning of each match. * * <p> Groups beginning with {@code (?} are either pure, <i>non-capturing</i> groups * that do not capture text and do not count towards the group total, or * <i>named-capturing</i> group. * * <h2> Unicode support </h2> * * <p> This class is in conformance with Level 1 of <a * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical * Standard #18: Unicode Regular Expression</i></a>, plus RL2.1 * Canonical Equivalents and RL2.2 Extended Grapheme Clusters. * <p> * <b>Unicode escape sequences</b> such as <code>\u2014</code> in Java source code * are processed as described in section 3.3 of * <cite>The Java™ Language Specification</cite>. * Such escape sequences are also implemented directly by the regular-expression * parser so that Unicode escapes can be used in expressions that are read from * files or from the keyboard. Thus the strings <code>"\u2014"</code> and * {@code "\\u2014"}, while not equal, compile into the same pattern, which * matches the character with hexadecimal value {@code 0x2014}. * <p> * A Unicode character can also be represented by using its <b>Hex notation</b> * (hexadecimal code point value) directly as described in construct * <code>\x{...}</code>, for example a supplementary character U+2011F can be * specified as <code>\x{2011F}</code>, instead of two consecutive Unicode escape * sequences of the surrogate pair <code>\uD840</code><code>\uDD1F</code>. * <p> * <b>Unicode character names</b> are supported by the named character construct * <code>\N{</code>...<code>}</code>, for example, <code>\N{WHITE SMILING FACE}</code> * specifies character <code>\u263A</code>. The character names supported * by this class are the valid Unicode character names matched by * {@link java.lang.Character#codePointOf(String) Character.codePointOf(name)}. * <p> * <a href="http://www.unicode.org/reports/tr18/#Default_Grapheme_Clusters"> * <b>Unicode extended grapheme clusters</b></a> are supported by the grapheme * cluster matcher {@code \X} and the corresponding boundary matcher {@code \b{g}}. * <p> * Unicode scripts, blocks, categories and binary properties are written with * the {@code \p} and {@code \P} constructs as in Perl. * <code>\p{</code><i>prop</i><code>}</code> matches if * the input has the property <i>prop</i>, while <code>\P{</code><i>prop</i><code>}</code> * does not match if the input has that property. * <p> * Scripts, blocks, categories and binary properties can be used both inside * and outside of a character class. * * <p> * <b><a id="usc">Scripts</a></b> are specified either with the prefix {@code Is}, as in * {@code IsHiragana}, or by using the {@code script} keyword (or its short * form {@code sc}) as in {@code script=Hiragana} or {@code sc=Hiragana}. * <p> * The script names supported by {@code Pattern} are the valid script names * accepted and defined by * {@link java.lang.Character.UnicodeScript#forName(String) UnicodeScript.forName}. * * <p> * <b><a id="ubc">Blocks</a></b> are specified with the prefix {@code In}, as in * {@code InMongolian}, or by using the keyword {@code block} (or its short * form {@code blk}) as in {@code block=Mongolian} or {@code blk=Mongolian}. * <p> * The block names supported by {@code Pattern} are the valid block names * accepted and defined by * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}. * <p> * * <b><a id="ucc">Categories</a></b> may be specified with the optional prefix {@code Is}: * Both {@code \p{L}} and {@code \p{IsL}} denote the category of Unicode * letters. Same as scripts and blocks, categories can also be specified * by using the keyword {@code general_category} (or its short form * {@code gc}) as in {@code general_category=Lu} or {@code gc=Lu}. * <p> * The supported categories are those of * <a href="http://www.unicode.org/unicode/standard/standard.html"> * <i>The Unicode Standard</i></a> in the version specified by the * {@link java.lang.Character Character} class. The category names are those * defined in the Standard, both normative and informative. * <p> * * <b><a id="ubpc">Binary properties</a></b> are specified with the prefix {@code Is}, as in * {@code IsAlphabetic}. The supported binary properties by {@code Pattern} * are * <ul> * <li> Alphabetic * <li> Ideographic * <li> Letter * <li> Lowercase * <li> Uppercase * <li> Titlecase * <li> Punctuation * <Li> Control * <li> White_Space * <li> Digit * <li> Hex_Digit * <li> Join_Control * <li> Noncharacter_Code_Point * <li> Assigned * </ul> * <p> * The following <b>Predefined Character classes</b> and <b>POSIX character classes</b> * are in conformance with the recommendation of <i>Annex C: Compatibility Properties</i> * of <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Regular Expression * </i></a>, when {@link #UNICODE_CHARACTER_CLASS} flag is specified. * * <table class="striped"> * <caption style="display:none">predefined and posix character classes in Unicode mode</caption> * <thead> * <tr> * <th scope="col" id="predef_classes">Classes</th> * <th scope="col" id="predef_matches">Matches</th> * </tr> * </thead> * <tbody> * <tr><th scope="row">{@code \p{Lower}}</th> * <td>A lowercase character:{@code \p{IsLowercase}}</td></tr> * <tr><th scope="row">{@code \p{Upper}}</th> * <td>An uppercase character:{@code \p{IsUppercase}}</td></tr> * <tr><th scope="row">{@code \p{ASCII}}</th> * <td>All ASCII:{@code [\x00-\x7F]}</td></tr> * <tr><th scope="row">{@code \p{Alpha}}</th> * <td>An alphabetic character:{@code \p{IsAlphabetic}}</td></tr> * <tr><th scope="row">{@code \p{Digit}}</th> * <td>A decimal digit character:{@code \p{IsDigit}}</td></tr> * <tr><th scope="row">{@code \p{Alnum}}</th> * <td>An alphanumeric character:{@code [\p{IsAlphabetic}\p{IsDigit}]}</td></tr> * <tr><th scope="row">{@code \p{Punct}}</th> * <td>A punctuation character:{@code \p{IsPunctuation}}</td></tr> * <tr><th scope="row">{@code \p{Graph}}</th> * <td>A visible character: {@code [^\p{IsWhite_Space}\p{gc=Cc}\p{gc=Cs}\p{gc=Cn}]}</td></tr> * <tr><th scope="row">{@code \p{Print}}</th> * <td>A printable character: {@code [\p{Graph}\p{Blank}&&[^\p{Cntrl}]]}</td></tr> * <tr><th scope="row">{@code \p{Blank}}</th> * <td>A space or a tab: {@code [\p{IsWhite_Space}&&[^\p{gc=Zl}\p{gc=Zp}\x0a\x0b\x0c\x0d\x85]]}</td></tr> * <tr><th scope="row">{@code \p{Cntrl}}</th> * <td>A control character: {@code \p{gc=Cc}}</td></tr> * <tr><th scope="row">{@code \p{XDigit}}</th> * <td>A hexadecimal digit: {@code [\p{gc=Nd}\p{IsHex_Digit}]}</td></tr> * <tr><th scope="row">{@code \p{Space}}</th> * <td>A whitespace character:{@code \p{IsWhite_Space}}</td></tr> * <tr><th scope="row">{@code \d}</th> * <td>A digit: {@code \p{IsDigit}}</td></tr> * <tr><th scope="row">{@code \D}</th> * <td>A non-digit: {@code [^\d]}</td></tr> * <tr><th scope="row">{@code \s}</th> * <td>A whitespace character: {@code \p{IsWhite_Space}}</td></tr> * <tr><th scope="row">{@code \S}</th> * <td>A non-whitespace character: {@code [^\s]}</td></tr> * <tr><th scope="row">{@code \w}</th> * <td>A word character: {@code [\p{Alpha}\p{gc=Mn}\p{gc=Me}\p{gc=Mc}\p{Digit}\p{gc=Pc}\p{IsJoin_Control}]}</td></tr> * <tr><th scope="row">{@code \W}</th> * <td>A non-word character: {@code [^\w]}</td></tr> * </tbody> * </table> * <p> * <a id="jcc"> * Categories that behave like the java.lang.Character * boolean is<i>methodname</i> methods (except for the deprecated ones) are * available through the same <code>\p{</code><i>prop</i><code>}</code> syntax where * the specified property has the name <code>java<i>methodname</i></code></a>. * * <h2> Comparison to Perl 5 </h2> * * <p>The {@code Pattern} engine performs traditional NFA-based matching * with ordered alternation as occurs in Perl 5. * * <p> Perl constructs not supported by this class: </p> * * <ul> * <li><p> The backreference constructs, <code>\g{</code><i>n</i><code>}</code> for * the <i>n</i><sup>th</sup><a href="#cg">capturing group</a> and * <code>\g{</code><i>name</i><code>}</code> for * <a href="#groupname">named-capturing group</a>. * </p></li> * * <li><p> The conditional constructs * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code )} and * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code |}<i>Y</i>{@code )}, * </p></li> * * <li><p> The embedded code constructs <code>(?{</code><i>code</i><code>})</code> * and <code>(??{</code><i>code</i><code>})</code>,</p></li> * * <li><p> The embedded comment syntax {@code (?#comment)}, and </p></li> * * <li><p> The preprocessing operations {@code \l} <code>\u</code>, * {@code \L}, and {@code \U}. </p></li> * * </ul> * * <p> Constructs supported by this class but not by Perl: </p> * * <ul> * * <li><p> Character-class union and intersection as described * <a href="#cc">above</a>.</p></li> * * </ul> * * <p> Notable differences from Perl: </p> * * <ul> * * <li><p> In Perl, {@code \1} through {@code \9} are always interpreted * as back references; a backslash-escaped number greater than {@code 9} is * treated as a back reference if at least that many subexpressions exist, * otherwise it is interpreted, if possible, as an octal escape. In this * class octal escapes must always begin with a zero. In this class, * {@code \1} through {@code \9} are always interpreted as back * references, and a larger number is accepted as a back reference if at * least that many subexpressions exist at that point in the regular * expression, otherwise the parser will drop digits until the number is * smaller or equal to the existing number of groups or it is one digit. * </p></li> * * <li><p> Perl uses the {@code g} flag to request a match that resumes * where the last match left off. This functionality is provided implicitly * by the {@link Matcher} class: Repeated invocations of the {@link * Matcher#find find} method will resume where the last match left off, * unless the matcher is reset. </p></li> * * <li><p> In Perl, embedded flags at the top level of an expression affect * the whole expression. In this class, embedded flags always take effect * at the point at which they appear, whether they are at the top level or * within a group; in the latter case, flags are restored at the end of the * group just as in Perl. </p></li> * * </ul> * * * <p> For a more precise description of the behavior of regular expression * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/"> * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl, * O'Reilly and Associates, 2006.</a> * </p> * * @see java.lang.String#split(String, int) * @see java.lang.String#split(String) * * @author Mike McCloskey * @author Mark Reinhold * @author JSR-51 Expert Group * @since 1.4 * @spec JSR-51 */ public final class Pattern implements java.io.Serializable { /** * Regular expression modifier values. Instead of being passed as * arguments, they can also be passed as inline modifiers. * For example, the following statements have the same effect. * <pre> * Pattern p1 = Pattern.compile("abc", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE); * Pattern p2 = Pattern.compile("(?im)abc", 0); * </pre> */ /** * Enables Unix lines mode. * * <p> In this mode, only the {@code '\n'} line terminator is recognized * in the behavior of {@code .}, {@code ^}, and {@code $}. * * <p> Unix lines mode can also be enabled via the embedded flag * expression {@code (?d)}. */ public static final int UNIX_LINES = 0x01; /** * Enables case-insensitive matching. * * <p> By default, case-insensitive matching assumes that only characters * in the US-ASCII charset are being matched. Unicode-aware * case-insensitive matching can be enabled by specifying the {@link * #UNICODE_CASE} flag in conjunction with this flag. * * <p> Case-insensitive matching can also be enabled via the embedded flag * expression {@code (?i)}. * * <p> Specifying this flag may impose a slight performance penalty. </p> */ public static final int CASE_INSENSITIVE = 0x02; /** * Permits whitespace and comments in pattern. * * <p> In this mode, whitespace is ignored, and embedded comments starting * with {@code #} are ignored until the end of a line. * * <p> Comments mode can also be enabled via the embedded flag * expression {@code (?x)}. */ public static final int COMMENTS = 0x04; /** * Enables multiline mode. * * <p> In multiline mode the expressions {@code ^} and {@code $} match * just after or just before, respectively, a line terminator or the end of * the input sequence. By default these expressions only match at the * beginning and the end of the entire input sequence. * * <p> Multiline mode can also be enabled via the embedded flag * expression {@code (?m)}. </p> */ public static final int MULTILINE = 0x08; /** * Enables literal parsing of the pattern. * * <p> When this flag is specified then the input string that specifies * the pattern is treated as a sequence of literal characters. * Metacharacters or escape sequences in the input sequence will be * given no special meaning. * * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on * matching when used in conjunction with this flag. The other flags * become superfluous. * * <p> There is no embedded flag character for enabling literal parsing. * @since 1.5 */ public static final int LITERAL = 0x10; /** * Enables dotall mode. * * <p> In dotall mode, the expression {@code .} matches any character, * including a line terminator. By default this expression does not match * line terminators. * * <p> Dotall mode can also be enabled via the embedded flag * expression {@code (?s)}. (The {@code s} is a mnemonic for * "single-line" mode, which is what this is called in Perl.) </p> */ public static final int DOTALL = 0x20; /** * Enables Unicode-aware case folding. * * <p> When this flag is specified then case-insensitive matching, when * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner * consistent with the Unicode Standard. By default, case-insensitive * matching assumes that only characters in the US-ASCII charset are being * matched. * * <p> Unicode-aware case folding can also be enabled via the embedded flag * expression {@code (?u)}. * * <p> Specifying this flag may impose a performance penalty. </p> */ public static final int UNICODE_CASE = 0x40; /** * Enables canonical equivalence. * * <p> When this flag is specified then two characters will be considered * to match if, and only if, their full canonical decompositions match. * The expression <code>"a\u030A"</code>, for example, will match the * string <code>"\u00E5"</code> when this flag is specified. By default, * matching does not take canonical equivalence into account. * * <p> There is no embedded flag character for enabling canonical * equivalence. * * <p> Specifying this flag may impose a performance penalty. </p> */ public static final int CANON_EQ = 0x80; /** * Enables the Unicode version of <i>Predefined character classes</i> and * <i>POSIX character classes</i>. * * <p> When this flag is specified then the (US-ASCII only) * <i>Predefined character classes</i> and <i>POSIX character classes</i> * are in conformance with * <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical * Standard #18: Unicode Regular Expression</i></a> * <i>Annex C: Compatibility Properties</i>. * <p> * The UNICODE_CHARACTER_CLASS mode can also be enabled via the embedded * flag expression {@code (?U)}. * <p> * The flag implies UNICODE_CASE, that is, it enables Unicode-aware case * folding. * <p> * Specifying this flag may impose a performance penalty. </p> * @since 1.7 */ public static final int UNICODE_CHARACTER_CLASS = 0x100; /** * Contains all possible flags for compile(regex, flags). */ private static final int ALL_FLAGS = CASE_INSENSITIVE | MULTILINE | DOTALL | UNICODE_CASE | CANON_EQ | UNIX_LINES | LITERAL | UNICODE_CHARACTER_CLASS | COMMENTS; /* Pattern has only two serialized components: The pattern string * and the flags, which are all that is needed to recompile the pattern * when it is deserialized. */ /** use serialVersionUID from Merlin b59 for interoperability */ private static final long serialVersionUID = 5073258162644648461L; /** * The original regular-expression pattern string. * * @serial */ private String pattern; /** * The original pattern flags. * * @serial */ private int flags; /** * The temporary pattern flags used during compiling. The flags might be turn * on and off by embedded flag. */ private transient int flags0; /** * Boolean indicating this Pattern is compiled; this is necessary in order * to lazily compile deserialized Patterns. */ private transient volatile boolean compiled; /** * The normalized pattern string. */ private transient String normalizedPattern; /** * The starting point of state machine for the find operation. This allows * a match to start anywhere in the input. */ transient Node root; /** * The root of object tree for a match operation. The pattern is matched * at the beginning. This may include a find that uses BnM or a First * node. */ transient Node matchRoot; /** * Temporary storage used by parsing pattern slice. */ transient int[] buffer; /** * A temporary storage used for predicate for double return. */ transient CharPredicate predicate; /** * Map the "name" of the "named capturing group" to its group id * node. */ transient volatile Map<String, Integer> namedGroups; /** * Temporary storage used while parsing group references. */ transient GroupHead[] groupNodes; /** * Temporary storage used to store the top level closure nodes. */ transient List<Node> topClosureNodes; /** * The number of top greedy closure nodes in this Pattern. Used by * matchers to allocate storage needed for a IntHashSet to keep the * beginning pos {@code i} of all failed match. */ transient int localTCNCount; /* * Turn off the stop-exponential-backtracking optimization if there * is a group ref in the pattern. */ transient boolean hasGroupRef; /** * Temporary null terminated code point array used by pattern compiling. */ private transient int[] temp; /** * The number of capturing groups in this Pattern. Used by matchers to * allocate storage needed to perform a match. */ transient int capturingGroupCount; /** * The local variable count used by parsing tree. Used by matchers to * allocate storage needed to perform a match. */ transient int localCount; /** * Index into the pattern string that keeps track of how much has been * parsed. */ private transient int cursor; /** * Holds the length of the pattern string. */ private transient int patternLength; /** * If the Start node might possibly match supplementary characters. * It is set to true during compiling if * (1) There is supplementary char in pattern, or * (2) There is complement node of a "family" CharProperty */ private transient boolean hasSupplementary; /** * Compiles the given regular expression into a pattern. * * @param regex * The expression to be compiled * @return the given regular expression compiled into a pattern * @throws PatternSyntaxException * If the expression's syntax is invalid */ public static Pattern compile(String regex) { return new Pattern(regex, 0); } /** * Compiles the given regular expression into a pattern with the given * flags. * * @param regex * The expression to be compiled * * @param flags * Match flags, a bit mask that may include * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL}, * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES}, * {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS} * and {@link #COMMENTS} * * @return the given regular expression compiled into a pattern with the given flags * @throws IllegalArgumentException * If bit values other than those corresponding to the defined * match flags are set in {@code flags} * * @throws PatternSyntaxException * If the expression's syntax is invalid */ public static Pattern compile(String regex, int flags) { return new Pattern(regex, flags); } /** * Returns the regular expression from which this pattern was compiled. * * @return The source of this pattern */ public String pattern() { return pattern; } /** * <p>Returns the string representation of this pattern. This * is the regular expression from which this pattern was * compiled.</p> * * @return The string representation of this pattern * @since 1.5 */ public String toString() { return pattern; } /** * Creates a matcher that will match the given input against this pattern. * * @param input * The character sequence to be matched * * @return A new matcher for this pattern */ public Matcher matcher(CharSequence input) { if (!compiled) { synchronized (this) { if (!compiled) compile(); } } Matcher m = new Matcher(this, input); return m; } /** * Returns this pattern's match flags. * * @return The match flags specified when this pattern was compiled */ public int flags() { return flags0; } /** * Compiles the given regular expression and attempts to match the given * input against it. * * <p> An invocation of this convenience method of the form * * <blockquote><pre> * Pattern.matches(regex, input);</pre></blockquote> * * behaves in exactly the same way as the expression * * <blockquote><pre> * Pattern.compile(regex).matcher(input).matches()</pre></blockquote> * * <p> If a pattern is to be used multiple times, compiling it once and reusing * it will be more efficient than invoking this method each time. </p> * * @param regex * The expression to be compiled * * @param input * The character sequence to be matched * @return whether or not the regular expression matches on the input * @throws PatternSyntaxException * If the expression's syntax is invalid */ public static boolean matches(String regex, CharSequence input) { Pattern p = Pattern.compile(regex); Matcher m = p.matcher(input); return m.matches(); } /** * Splits the given input sequence around matches of this pattern. * * <p> The array returned by this method contains each substring of the * input sequence that is terminated by another subsequence that matches * this pattern or is terminated by the end of the input sequence. The * substrings in the array are in the order in which they occur in the * input. If this pattern does not match any subsequence of the input then * the resulting array has just one element, namely the input sequence in * string form. * * <p> When there is a positive-width match at the beginning of the input * sequence then an empty leading substring is included at the beginning * of the resulting array. A zero-width match at the beginning however * never produces such empty leading substring. * * <p> The {@code limit} parameter controls the number of times the * pattern is applied and therefore affects the length of the resulting * array. * <ul> * <li><p> * If the <i>limit</i> is positive then the pattern will be applied * at most <i>limit</i> - 1 times, the array's length will be * no greater than <i>limit</i>, and the array's last entry will contain * all input beyond the last matched delimiter.</p></li> * * <li><p> * If the <i>limit</i> is zero then the pattern will be applied as * many times as possible, the array can have any length, and trailing * empty strings will be discarded.</p></li> * * <li><p> * If the <i>limit</i> is negative then the pattern will be applied * as many times as possible and the array can have any length.</p></li> * </ul> * * <p> The input {@code "boo:and:foo"}, for example, yields the following * results with these parameters: * * <table class="plain" style="margin-left:2em;"> * <caption style="display:none">Split example showing regex, limit, and result</caption> * <thead> * <tr> * <th scope="col">Regex</th> * <th scope="col">Limit</th> * <th scope="col">Result</th> * </tr> * </thead> * <tbody> * <tr><th scope="row" rowspan="3" style="font-weight:normal">:</th> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">2</th> * <td>{@code { "boo", "and:foo" }}</td></tr> * <tr><!-- : --> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th> * <td>{@code { "boo", "and", "foo" }}</td></tr> * <tr><!-- : --> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th> * <td>{@code { "boo", "and", "foo" }}</td></tr> * <tr><th scope="row" rowspan="3" style="font-weight:normal">o</th> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th> * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr> * <tr><!-- o --> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th> * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr> * <tr><!-- o --> * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">0</th> * <td>{@code { "b", "", ":and:f" }}</td></tr> * </tbody> * </table> * * @param input * The character sequence to be split * * @param limit * The result threshold, as described above * * @return The array of strings computed by splitting the input * around matches of this pattern */ public String[] split(CharSequence input, int limit) { int index = 0; boolean matchLimited = limit > 0; ArrayList<String> matchList = new ArrayList<>(); Matcher m = matcher(input); // Add segments before each match found while (m.find()) { if (!matchLimited || matchList.size() < limit - 1) { if (index == 0 && index == m.start() && m.start() == m.end()) { // no empty leading substring included for zero-width match // at the beginning of the input char sequence. continue; } String match = input.subSequence(index, m.start()).toString(); matchList.add(match); index = m.end(); } else if (matchList.size() == limit - 1) { // last one String match = input.subSequence(index, input.length()).toString(); matchList.add(match); index = m.end(); } } // If no match was found, return this if (index == 0) return new String[] { input.toString() }; // Add remaining segment if (!matchLimited || matchList.size() < limit) matchList.add(input.subSequence(index, input.length()).toString()); // Construct result int resultSize = matchList.size(); if (limit == 0) while (resultSize > 0 && matchList.get(resultSize - 1).isEmpty()) resultSize--; String[] result = new String[resultSize]; return matchList.subList(0, resultSize).toArray(result); } /** * Splits the given input sequence around matches of this pattern. * * <p> This method works as if by invoking the two-argument {@link * #split(java.lang.CharSequence, int) split} method with the given input * sequence and a limit argument of zero. Trailing empty strings are * therefore not included in the resulting array. </p> * * <p> The input {@code "boo:and:foo"}, for example, yields the following * results with these expressions: * * <table class="plain" style="margin-left:2em"> * <caption style="display:none">Split examples showing regex and result</caption> * <thead> * <tr> * <th scope="col">Regex</th> * <th scope="col">Result</th> * </tr> * </thead> * <tbody> * <tr><th scope="row" style="text-weight:normal">:</th> * <td>{@code { "boo", "and", "foo" }}</td></tr> * <tr><th scope="row" style="text-weight:normal">o</th> * <td>{@code { "b", "", ":and:f" }}</td></tr> * </tbody> * </table> * * * @param input * The character sequence to be split * * @return The array of strings computed by splitting the input * around matches of this pattern */ public String[] split(CharSequence input) { return split(input, 0); } /** * Returns a literal pattern {@code String} for the specified * {@code String}. * * <p>This method produces a {@code String} that can be used to * create a {@code Pattern} that would match the string * {@code s} as if it were a literal pattern.</p> Metacharacters * or escape sequences in the input sequence will be given no special * meaning. * * @param s The string to be literalized * @return A literal string replacement * @since 1.5 */ public static String quote(String s) { int slashEIndex = s.indexOf("\\E"); if (slashEIndex == -1) return "\\Q" + s + "\\E"; int lenHint = s.length(); lenHint = (lenHint < Integer.MAX_VALUE - 8 - lenHint) ? (lenHint << 1) : (Integer.MAX_VALUE - 8); StringBuilder sb = new StringBuilder(lenHint); sb.append("\\Q"); int current = 0; do { sb.append(s, current, slashEIndex).append("\\E\\\\E\\Q"); current = slashEIndex + 2; } while ((slashEIndex = s.indexOf("\\E", current)) != -1); return sb.append(s, current, s.length()).append("\\E").toString(); } /** * Recompile the Pattern instance from a stream. The original pattern * string is read in and the object tree is recompiled from it. */ private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException { // Read in all fields s.defaultReadObject(); // reset the flags flags0 = flags; // Initialize counts capturingGroupCount = 1; localCount = 0; localTCNCount = 0; // if length > 0, the Pattern is lazily compiled if (pattern.isEmpty()) { root = new Start(lastAccept); matchRoot = lastAccept; compiled = true; } } /** * This private constructor is used to create all Patterns. The pattern * string and match flags are all that is needed to completely describe * a Pattern. An empty pattern string results in an object tree with * only a Start node and a LastNode node. */ private Pattern(String p, int f) { if ((f & ~ALL_FLAGS) != 0) { throw new IllegalArgumentException("Unknown flag 0x" + Integer.toHexString(f)); } pattern = p; flags = f; // to use UNICODE_CASE if UNICODE_CHARACTER_CLASS present if ((flags & UNICODE_CHARACTER_CLASS) != 0) flags |= UNICODE_CASE; // 'flags' for compiling flags0 = flags; // Reset group index count capturingGroupCount = 1; localCount = 0; localTCNCount = 0; if (!pattern.isEmpty()) { compile(); } else { root = new Start(lastAccept); matchRoot = lastAccept; } } /** * The pattern is converted to normalized form ({@link * java.text.Normalizer.Form#NFC NFC}, canonical decomposition, * followed by canonical composition for the character class * part, and {@link java.text.Normalizer.Form#NFD NFD}, * canonical decomposition for the rest), and then a pure * group is constructed to match canonical equivalences of the * characters. */ private static String normalize(String pattern) { int plen = pattern.length(); StringBuilder pbuf = new StringBuilder(plen); char last = 0; int lastStart = 0; char cc = 0; for (int i = 0; i < plen;) { char c = pattern.charAt(i); if (cc == 0 && // top level c == '\\' && i + 1 < plen && pattern.charAt(i + 1) == '\\') { i += 2; last = 0; continue; } if (c == '[' && last != '\\') { if (cc == 0) { if (lastStart < i) normalizeSlice(pattern, lastStart, i, pbuf); lastStart = i; } cc++; } else if (c == ']' && last != '\\') { cc--; if (cc == 0) { normalizeClazz(pattern, lastStart, i + 1, pbuf); lastStart = i + 1; } } last = c; i++; } assert (cc == 0); if (lastStart < plen) normalizeSlice(pattern, lastStart, plen, pbuf); return pbuf.toString(); } private static void normalizeSlice(String src, int off, int limit, StringBuilder dst) { int len = src.length(); int off0 = off; while (off < limit && ASCII.isAscii(src.charAt(off))) { off++; } if (off == limit) { dst.append(src, off0, limit); return; } off--; if (off < off0) off = off0; else dst.append(src, off0, off); while (off < limit) { int ch0 = src.codePointAt(off); if (".$|()[]{}^?*+\\".indexOf(ch0) != -1) { dst.append((char) ch0); off++; continue; } int j = Grapheme.nextBoundary(src, off, limit); int ch1; String seq = src.substring(off, j); String nfd = Normalizer.normalize(seq, Normalizer.Form.NFD); off = j; if (nfd.length() > 1) { ch0 = nfd.codePointAt(0); ch1 = nfd.codePointAt(Character.charCount(ch0)); if (Character.getType(ch1) == Character.NON_SPACING_MARK) { Set<String> altns = new LinkedHashSet<>(); altns.add(seq); produceEquivalentAlternation(nfd, altns); dst.append("(?:"); altns.forEach(s -> dst.append(s).append('|')); dst.delete(dst.length() - 1, dst.length()); dst.append(")"); continue; } } String nfc = Normalizer.normalize(seq, Normalizer.Form.NFC); if (!seq.equals(nfc) && !nfd.equals(nfc)) dst.append("(?:" + seq + "|" + nfd + "|" + nfc + ")"); else if (!seq.equals(nfd)) dst.append("(?:" + seq + "|" + nfd + ")"); else dst.append(seq); } } private static void normalizeClazz(String src, int off, int limit, StringBuilder dst) { dst.append(Normalizer.normalize(src.substring(off, limit), Form.NFC)); } /** * Given a specific sequence composed of a regular character and * combining marks that follow it, produce the alternation that will * match all canonical equivalences of that sequence. */ private static void produceEquivalentAlternation(String src, Set<String> dst) { int len = countChars(src, 0, 1); if (src.length() == len) { dst.add(src); // source has one character. return; } String base = src.substring(0, len); String combiningMarks = src.substring(len); String[] perms = producePermutations(combiningMarks); // Add combined permutations for (int x = 0; x < perms.length; x++) { String next = base + perms[x]; dst.add(next); next = composeOneStep(next); if (next != null) { produceEquivalentAlternation(next, dst); } } } /** * Returns an array of strings that have all the possible * permutations of the characters in the input string. * This is used to get a list of all possible orderings * of a set of combining marks. Note that some of the permutations * are invalid because of combining class collisions, and these * possibilities must be removed because they are not canonically * equivalent. */ private static String[] producePermutations(String input) { if (input.length() == countChars(input, 0, 1)) return new String[] { input }; if (input.length() == countChars(input, 0, 2)) { int c0 = Character.codePointAt(input, 0); int c1 = Character.codePointAt(input, Character.charCount(c0)); if (getClass(c1) == getClass(c0)) { return new String[] { input }; } String[] result = new String[2]; result[0] = input; StringBuilder sb = new StringBuilder(2); sb.appendCodePoint(c1); sb.appendCodePoint(c0); result[1] = sb.toString(); return result; } int length = 1; int nCodePoints = countCodePoints(input); for (int x = 1; x < nCodePoints; x++) length = length * (x + 1); String[] temp = new String[length]; int combClass[] = new int[nCodePoints]; for (int x = 0, i = 0; x < nCodePoints; x++) { int c = Character.codePointAt(input, i); combClass[x] = getClass(c); i += Character.charCount(c); } // For each char, take it out and add the permutations // of the remaining chars int index = 0; int len; // offset maintains the index in code units. loop: for (int x = 0, offset = 0; x < nCodePoints; x++, offset += len) { len = countChars(input, offset, 1); for (int y = x - 1; y >= 0; y--) { if (combClass[y] == combClass[x]) { continue loop; } } StringBuilder sb = new StringBuilder(input); String otherChars = sb.delete(offset, offset + len).toString(); String[] subResult = producePermutations(otherChars); String prefix = input.substring(offset, offset + len); for (String sre : subResult) temp[index++] = prefix + sre; } String[] result = new String[index]; System.arraycopy(temp, 0, result, 0, index); return result; } private static int getClass(int c) { return sun.text.Normalizer.getCombiningClass(c); } /** * Attempts to compose input by combining the first character * with the first combining mark following it. Returns a String * that is the composition of the leading character with its first * combining mark followed by the remaining combining marks. Returns * null if the first two characters cannot be further composed. */ private static String composeOneStep(String input) { int len = countChars(input, 0, 2); String firstTwoCharacters = input.substring(0, len); String result = Normalizer.normalize(firstTwoCharacters, Normalizer.Form.NFC); if (result.equals(firstTwoCharacters)) return null; else { String remainder = input.substring(len); return result + remainder; } } /** * Preprocess any \Q...\E sequences in `temp', meta-quoting them. * See the description of `quotemeta' in perlfunc(1). */ private void RemoveQEQuoting() { final int pLen = patternLength; int i = 0; while (i < pLen - 1) { if (temp[i] != '\\') i += 1; else if (temp[i + 1] != 'Q') i += 2; else break; } if (i >= pLen - 1) // No \Q sequence found return; int j = i; i += 2; int newTempLen; try { newTempLen = Math.addExact(j + 2, Math.multiplyExact(3, pLen - i)); } catch (ArithmeticException ae) { throw new OutOfMemoryError(); } int[] newtemp = new int[newTempLen]; System.arraycopy(temp, 0, newtemp, 0, j); boolean inQuote = true; boolean beginQuote = true; while (i < pLen) { int c = temp[i++]; if (!ASCII.isAscii(c) || ASCII.isAlpha(c)) { newtemp[j++] = c; } else if (ASCII.isDigit(c)) { if (beginQuote) { /* * A unicode escape \[0xu] could be before this quote, * and we don't want this numeric char to processed as * part of the escape. */ newtemp[j++] = '\\'; newtemp[j++] = 'x'; newtemp[j++] = '3'; } newtemp[j++] = c; } else if (c != '\\') { if (inQuote) newtemp[j++] = '\\'; newtemp[j++] = c; } else if (inQuote) { if (temp[i] == 'E') { i++; inQuote = false; } else { newtemp[j++] = '\\'; newtemp[j++] = '\\'; } } else { if (temp[i] == 'Q') { i++; inQuote = true; beginQuote = true; continue; } else { newtemp[j++] = c; if (i != pLen) newtemp[j++] = temp[i++]; } } beginQuote = false; } patternLength = j; temp = Arrays.copyOf(newtemp, j + 2); // double zero termination } /** * Copies regular expression to an int array and invokes the parsing * of the expression which will create the object tree. */ private void compile() { // Handle canonical equivalences if (has(CANON_EQ) && !has(LITERAL)) { normalizedPattern = normalize(pattern); } else { normalizedPattern = pattern; } patternLength = normalizedPattern.length(); // Copy pattern to int array for convenience // Use double zero to terminate pattern temp = new int[patternLength + 2]; hasSupplementary = false; int c, count = 0; // Convert all chars into code points for (int x = 0; x < patternLength; x += Character.charCount(c)) { c = normalizedPattern.codePointAt(x); if (isSupplementary(c)) { hasSupplementary = true; } temp[count++] = c; } patternLength = count; // patternLength now in code points if (!has(LITERAL)) RemoveQEQuoting(); // Allocate all temporary objects here. buffer = new int[32]; groupNodes = new GroupHead[10]; namedGroups = null; topClosureNodes = new ArrayList<>(10); if (has(LITERAL)) { // Literal pattern handling matchRoot = newSlice(temp, patternLength, hasSupplementary); matchRoot.next = lastAccept; } else { // Start recursive descent parsing matchRoot = expr(lastAccept); // Check extra pattern characters if (patternLength != cursor) { if (peek() == ')') { throw error("Unmatched closing ')'"); } else { throw error("Unexpected internal error"); } } } // Peephole optimization if (matchRoot instanceof Slice) { root = BnM.optimize(matchRoot); if (root == matchRoot) { root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot); } } else if (matchRoot instanceof Begin || matchRoot instanceof First) { root = matchRoot; } else { root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot); } // Optimize the greedy Loop to prevent exponential backtracking, IF there // is no group ref in this pattern. With a non-negative localTCNCount value, // the greedy type Loop, Curly will skip the backtracking for any starting // position "i" that failed in the past. if (!hasGroupRef) { for (Node node : topClosureNodes) { if (node instanceof Loop) { // non-deterministic-greedy-group ((Loop) node).posIndex = localTCNCount++; } } } // Release temporary storage temp = null; buffer = null; groupNodes = null; patternLength = 0; compiled = true; topClosureNodes = null; } Map<String, Integer> namedGroups() { Map<String, Integer> groups = namedGroups; if (groups == null) { namedGroups = groups = new HashMap<>(2); } return groups; } /** * Used to accumulate information about a subtree of the object graph * so that optimizations can be applied to the subtree. */ static final class TreeInfo { int minLength; int maxLength; boolean maxValid; boolean deterministic; TreeInfo() { reset(); } void reset() { minLength = 0; maxLength = 0; maxValid = true; deterministic = true; } } /* * The following private methods are mainly used to improve the * readability of the code. In order to let the Java compiler easily * inline them, we should not put many assertions or error checks in them. */ /** * Indicates whether a particular flag is set or not. */ private boolean has(int f) { return (flags0 & f) != 0; } /** * Match next character, signal error if failed. */ private void accept(int ch, String s) { int testChar = temp[cursor++]; if (has(COMMENTS)) testChar = parsePastWhitespace(testChar); if (ch != testChar) { throw error(s); } } /** * Mark the end of pattern with a specific character. */ private void mark(int c) { temp[patternLength] = c; } /** * Peek the next character, and do not advance the cursor. */ private int peek() { int ch = temp[cursor]; if (has(COMMENTS)) ch = peekPastWhitespace(ch); return ch; } /** * Read the next character, and advance the cursor by one. */ private int read() { int ch = temp[cursor++]; if (has(COMMENTS)) ch = parsePastWhitespace(ch); return ch; } /** * Read the next character, and advance the cursor by one, * ignoring the COMMENTS setting */ private int readEscaped() { int ch = temp[cursor++]; return ch; } /** * Advance the cursor by one, and peek the next character. */ private int next() { int ch = temp[++cursor]; if (has(COMMENTS)) ch = peekPastWhitespace(ch); return ch; } /** * Advance the cursor by one, and peek the next character, * ignoring the COMMENTS setting */ private int nextEscaped() { int ch = temp[++cursor]; return ch; } /** * If in xmode peek past whitespace and comments. */ private int peekPastWhitespace(int ch) { while (ASCII.isSpace(ch) || ch == '#') { while (ASCII.isSpace(ch)) ch = temp[++cursor]; if (ch == '#') { ch = peekPastLine(); } } return ch; } /** * If in xmode parse past whitespace and comments. */ private int parsePastWhitespace(int ch) { while (ASCII.isSpace(ch) || ch == '#') { while (ASCII.isSpace(ch)) ch = temp[cursor++]; if (ch == '#') ch = parsePastLine(); } return ch; } /** * xmode parse past comment to end of line. */ private int parsePastLine() { int ch = temp[cursor++]; while (ch != 0 && !isLineSeparator(ch)) ch = temp[cursor++]; return ch; } /** * xmode peek past comment to end of line. */ private int peekPastLine() { int ch = temp[++cursor]; while (ch != 0 && !isLineSeparator(ch)) ch = temp[++cursor]; return ch; } /** * Determines if character is a line separator in the current mode */ private boolean isLineSeparator(int ch) { if (has(UNIX_LINES)) { return ch == '\n'; } else { return (ch == '\n' || ch == '\r' || (ch | 1) == '\u2029' || ch == '\u0085'); } } /** * Read the character after the next one, and advance the cursor by two. */ private int skip() { int i = cursor; int ch = temp[i + 1]; cursor = i + 2; return ch; } /** * Unread one next character, and retreat cursor by one. */ private void unread() { cursor--; } /** * Internal method used for handling all syntax errors. The pattern is * displayed with a pointer to aid in locating the syntax error. */ private PatternSyntaxException error(String s) { return new PatternSyntaxException(s, normalizedPattern, cursor - 1); } /** * Determines if there is any supplementary character or unpaired * surrogate in the specified range. */ private boolean findSupplementary(int start, int end) { for (int i = start; i < end; i++) { if (isSupplementary(temp[i])) return true; } return false; } /** * Determines if the specified code point is a supplementary * character or unpaired surrogate. */ private static final boolean isSupplementary(int ch) { return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT || Character.isSurrogate((char) ch); } /** * The following methods handle the main parsing. They are sorted * according to their precedence order, the lowest one first. */ /** * The expression is parsed with branch nodes added for alternations. * This may be called recursively to parse sub expressions that may * contain alternations. */ private Node expr(Node end) { Node prev = null; Node firstTail = null; Branch branch = null; Node branchConn = null; for (;;) { Node node = sequence(end); Node nodeTail = root; //double return if (prev == null) { prev = node; firstTail = nodeTail; } else { // Branch if (branchConn == null) { branchConn = new BranchConn(); branchConn.next = end; } if (node == end) { // if the node returned from sequence() is "end" // we have an empty expr, set a null atom into // the branch to indicate to go "next" directly. node = null; } else { // the "tail.next" of each atom goes to branchConn nodeTail.next = branchConn; } if (prev == branch) { branch.add(node); } else { if (prev == end) { prev = null; } else { // replace the "end" with "branchConn" at its tail.next // when put the "prev" into the branch as the first atom. firstTail.next = branchConn; } prev = branch = new Branch(prev, node, branchConn); } } if (peek() != '|') { return prev; } next(); } } @SuppressWarnings("fallthrough") /** * Parsing of sequences between alternations. */ private Node sequence(Node end) { Node head = null; Node tail = null; Node node; LOOP: for (;;) { int ch = peek(); switch (ch) { case '(': // Because group handles its own closure, // we need to treat it differently node = group0(); // Check for comment or flag group if (node == null) continue; if (head == null) head = node; else tail.next = node; // Double return: Tail was returned in root tail = root; continue; case '[': if (has(CANON_EQ) && !has(LITERAL)) node = new NFCCharProperty(clazz(true)); else node = newCharProperty(clazz(true)); break; case '\\': ch = nextEscaped(); if (ch == 'p' || ch == 'P') { boolean oneLetter = true; boolean comp = (ch == 'P'); ch = next(); // Consume { if present if (ch != '{') { unread(); } else { oneLetter = false; } // node = newCharProperty(family(oneLetter, comp)); if (has(CANON_EQ) && !has(LITERAL)) node = new NFCCharProperty(family(oneLetter, comp)); else node = newCharProperty(family(oneLetter, comp)); } else { unread(); node = atom(); } break; case '^': next(); if (has(MULTILINE)) { if (has(UNIX_LINES)) node = new UnixCaret(); else node = new Caret(); } else { node = new Begin(); } break; case '$': next(); if (has(UNIX_LINES)) node = new UnixDollar(has(MULTILINE)); else node = new Dollar(has(MULTILINE)); break; case '.': next(); if (has(DOTALL)) { node = new CharProperty(ALL()); } else { if (has(UNIX_LINES)) { node = new CharProperty(UNIXDOT()); } else { node = new CharProperty(DOT()); } } break; case '|': case ')': break LOOP; case ']': // Now interpreting dangling ] and } as literals case '}': node = atom(); break; case '?': case '*': case '+': next(); throw error("Dangling meta character '" + ((char) ch) + "'"); case 0: if (cursor >= patternLength) { break LOOP; } // Fall through default: node = atom(); break; } node = closure(node); /* save the top dot-greedy nodes (.*, .+) as well if (node instanceof GreedyCharProperty && ((GreedyCharProperty)node).cp instanceof Dot) { topClosureNodes.add(node); } */ if (head == null) { head = tail = node; } else { tail.next = node; tail = node; } } if (head == null) { return end; } tail.next = end; root = tail; //double return return head; } @SuppressWarnings("fallthrough") /** * Parse and add a new Single or Slice. */ private Node atom() { int first = 0; int prev = -1; boolean hasSupplementary = false; int ch = peek(); for (;;) { switch (ch) { case '*': case '+': case '?': case '{': if (first > 1) { cursor = prev; // Unwind one character first--; } break; case '$': case '.': case '^': case '(': case '[': case '|': case ')': break; case '\\': ch = nextEscaped(); if (ch == 'p' || ch == 'P') { // Property if (first > 0) { // Slice is waiting; handle it first unread(); break; } else { // No slice; just return the family node boolean comp = (ch == 'P'); boolean oneLetter = true; ch = next(); // Consume { if present if (ch != '{') unread(); else oneLetter = false; if (has(CANON_EQ) && !has(LITERAL)) return new NFCCharProperty(family(oneLetter, comp)); else return newCharProperty(family(oneLetter, comp)); } } unread(); prev = cursor; ch = escape(false, first == 0, false); if (ch >= 0) { append(ch, first); first++; if (isSupplementary(ch)) { hasSupplementary = true; } ch = peek(); continue; } else if (first == 0) { return root; } // Unwind meta escape sequence cursor = prev; break; case 0: if (cursor >= patternLength) { break; } // Fall through default: prev = cursor; append(ch, first); first++; if (isSupplementary(ch)) { hasSupplementary = true; } ch = next(); continue; } break; } if (first == 1) { return newCharProperty(single(buffer[0])); } else { return newSlice(buffer, first, hasSupplementary); } } private void append(int ch, int index) { int len = buffer.length; if (index - len >= 0) { len = ArraysSupport.newLength(len, 1 + index - len, /* minimum growth */ len /* preferred growth */); buffer = Arrays.copyOf(buffer, len); } buffer[index] = ch; } /** * Parses a backref greedily, taking as many numbers as it * can. The first digit is always treated as a backref, but * multi digit numbers are only treated as a backref if at * least that many backrefs exist at this point in the regex. */ private Node ref(int refNum) { boolean done = false; while (!done) { int ch = peek(); switch (ch) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': int newRefNum = (refNum * 10) + (ch - '0'); // Add another number if it doesn't make a group // that doesn't exist if (capturingGroupCount - 1 < newRefNum) { done = true; break; } refNum = newRefNum; read(); break; default: done = true; break; } } hasGroupRef = true; if (has(CASE_INSENSITIVE)) return new CIBackRef(refNum, has(UNICODE_CASE)); else return new BackRef(refNum); } /** * Parses an escape sequence to determine the actual value that needs * to be matched. * If -1 is returned and create was true a new object was added to the tree * to handle the escape sequence. * If the returned value is greater than zero, it is the value that * matches the escape sequence. */ private int escape(boolean inclass, boolean create, boolean isrange) { int ch = skip(); switch (ch) { case '0': return o(); case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': if (inclass) break; if (create) { root = ref((ch - '0')); } return -1; case 'A': if (inclass) break; if (create) root = new Begin(); return -1; case 'B': if (inclass) break; if (create) root = new Bound(Bound.NONE, has(UNICODE_CHARACTER_CLASS)); return -1; case 'C': break; case 'D': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT(); predicate = predicate.negate(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'E': case 'F': break; case 'G': if (inclass) break; if (create) root = new LastMatch(); return -1; case 'H': if (create) { predicate = HorizWS().negate(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'I': case 'J': case 'K': case 'L': case 'M': break; case 'N': return N(); case 'O': case 'P': case 'Q': break; case 'R': if (inclass) break; if (create) root = new LineEnding(); return -1; case 'S': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE(); predicate = predicate.negate(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'T': case 'U': break; case 'V': if (create) { predicate = VertWS().negate(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'W': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.WORD() : CharPredicates.ASCII_WORD(); predicate = predicate.negate(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'X': if (inclass) break; if (create) { root = new XGrapheme(); } return -1; case 'Y': break; case 'Z': if (inclass) break; if (create) { if (has(UNIX_LINES)) root = new UnixDollar(false); else root = new Dollar(false); } return -1; case 'a': return '\007'; case 'b': if (inclass) break; if (create) { if (peek() == '{') { if (skip() == 'g') { if (read() == '}') { root = new GraphemeBound(); return -1; } break; // error missing trailing } } unread(); unread(); } root = new Bound(Bound.BOTH, has(UNICODE_CHARACTER_CLASS)); } return -1; case 'c': return c(); case 'd': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'e': return '\033'; case 'f': return '\f'; case 'g': break; case 'h': if (create) { predicate = HorizWS(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'i': case 'j': break; case 'k': if (inclass) break; if (read() != '<') throw error("\\k is not followed by '<' for named capturing group"); String name = groupname(read()); if (!namedGroups().containsKey(name)) throw error("named capturing group <" + name + "> does not exist"); if (create) { hasGroupRef = true; if (has(CASE_INSENSITIVE)) root = new CIBackRef(namedGroups().get(name), has(UNICODE_CASE)); else root = new BackRef(namedGroups().get(name)); } return -1; case 'l': case 'm': break; case 'n': return '\n'; case 'o': case 'p': case 'q': break; case 'r': return '\r'; case 's': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE(); if (!inclass) root = newCharProperty(predicate); } return -1; case 't': return '\t'; case 'u': return u(); case 'v': // '\v' was implemented as VT/0x0B in releases < 1.8 (though // undocumented). In JDK8 '\v' is specified as a predefined // character class for all vertical whitespace characters. // So [-1, root=VertWS node] pair is returned (instead of a // single 0x0B). This breaks the range if '\v' is used as // the start or end value, such as [\v-...] or [...-\v], in // which a single definite value (0x0B) is expected. For // compatibility concern '\013'/0x0B is returned if isrange. if (isrange) return '\013'; if (create) { predicate = VertWS(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'w': if (create) { predicate = has(UNICODE_CHARACTER_CLASS) ? CharPredicates.WORD() : CharPredicates.ASCII_WORD(); if (!inclass) root = newCharProperty(predicate); } return -1; case 'x': return x(); case 'y': break; case 'z': if (inclass) break; if (create) root = new End(); return -1; default: return ch; } throw error("Illegal/unsupported escape sequence"); } /** * Parse a character class, and return the node that matches it. * * Consumes a ] on the way out if consume is true. Usually consume * is true except for the case of [abc&&def] where def is a separate * right hand node with "understood" brackets. */ private CharPredicate clazz(boolean consume) { CharPredicate prev = null; CharPredicate curr = null; BitClass bits = new BitClass(); boolean isNeg = false; boolean hasBits = false; int ch = next(); // Negates if first char in a class, otherwise literal if (ch == '^' && temp[cursor - 1] == '[') { ch = next(); isNeg = true; } for (;;) { switch (ch) { case '[': curr = clazz(true); if (prev == null) prev = curr; else prev = prev.union(curr); ch = peek(); continue; case '&': ch = next(); if (ch == '&') { ch = next(); CharPredicate right = null; while (ch != ']' && ch != '&') { if (ch == '[') { if (right == null) right = clazz(true); else right = right.union(clazz(true)); } else { // abc&&def unread(); right = clazz(false); } ch = peek(); } if (hasBits) { // bits used, union has high precedence if (prev == null) { prev = curr = bits; } else { prev = prev.union(bits); } hasBits = false; } if (right != null) curr = right; if (prev == null) { if (right == null) throw error("Bad class syntax"); else prev = right; } else { prev = prev.and(curr); } } else { // treat as a literal & unread(); break; } continue; case 0: if (cursor >= patternLength) throw error("Unclosed character class"); break; case ']': if (prev != null || hasBits) { if (consume) next(); if (prev == null) prev = bits; else if (hasBits) prev = prev.union(bits); if (isNeg) return prev.negate(); return prev; } break; default: break; } curr = range(bits); if (curr == null) { // the bits used hasBits = true; } else { if (prev == null) prev = curr; else if (prev != curr) prev = prev.union(curr); } ch = peek(); } } private CharPredicate bitsOrSingle(BitClass bits, int ch) { /* Bits can only handle codepoints in [u+0000-u+00ff] range. Use "single" node instead of bits when dealing with unicode case folding for codepoints listed below. (1)Uppercase out of range: u+00ff, u+00b5 toUpperCase(u+00ff) -> u+0178 toUpperCase(u+00b5) -> u+039c (2)LatinSmallLetterLongS u+17f toUpperCase(u+017f) -> u+0053 (3)LatinSmallLetterDotlessI u+131 toUpperCase(u+0131) -> u+0049 (4)LatinCapitalLetterIWithDotAbove u+0130 toLowerCase(u+0130) -> u+0069 (5)KelvinSign u+212a toLowerCase(u+212a) ==> u+006B (6)AngstromSign u+212b toLowerCase(u+212b) ==> u+00e5 */ if (ch < 256 && !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) && (ch == 0xff || ch == 0xb5 || ch == 0x49 || ch == 0x69 || //I and i ch == 0x53 || ch == 0x73 || //S and s ch == 0x4b || ch == 0x6b || //K and k ch == 0xc5 || ch == 0xe5))) { //A+ring bits.add(ch, flags0); return null; } return single(ch); } /** * Returns a suitably optimized, single character predicate */ private CharPredicate single(final int ch) { if (has(CASE_INSENSITIVE)) { int lower, upper; if (has(UNICODE_CASE)) { upper = Character.toUpperCase(ch); lower = Character.toLowerCase(upper); // Unicode case insensitive matches if (upper != lower) return SingleU(lower); } else if (ASCII.isAscii(ch)) { lower = ASCII.toLower(ch); upper = ASCII.toUpper(ch); // Case insensitive matches a given BMP character if (lower != upper) return SingleI(lower, upper); } } if (isSupplementary(ch)) return SingleS(ch); return Single(ch); // Match a given BMP character } /** * Parse a single character or a character range in a character class * and return its representative node. */ private CharPredicate range(BitClass bits) { int ch = peek(); if (ch == '\\') { ch = nextEscaped(); if (ch == 'p' || ch == 'P') { // A property boolean comp = (ch == 'P'); boolean oneLetter = true; // Consume { if present ch = next(); if (ch != '{') unread(); else oneLetter = false; return family(oneLetter, comp); } else { // ordinary escape boolean isrange = temp[cursor + 1] == '-'; unread(); ch = escape(true, true, isrange); if (ch == -1) return predicate; } } else { next(); } if (ch >= 0) { if (peek() == '-') { int endRange = temp[cursor + 1]; if (endRange == '[') { return bitsOrSingle(bits, ch); } if (endRange != ']') { next(); int m = peek(); if (m == '\\') { m = escape(true, false, true); } else { next(); } if (m < ch) { throw error("Illegal character range"); } if (has(CASE_INSENSITIVE)) { if (has(UNICODE_CASE)) return CIRangeU(ch, m); return CIRange(ch, m); } else { return Range(ch, m); } } } return bitsOrSingle(bits, ch); } throw error("Unexpected character '" + ((char) ch) + "'"); } /** * Parses a Unicode character family and returns its representative node. */ private CharPredicate family(boolean singleLetter, boolean isComplement) { next(); String name; CharPredicate p = null; if (singleLetter) { int c = temp[cursor]; if (!Character.isSupplementaryCodePoint(c)) { name = String.valueOf((char) c); } else { name = new String(temp, cursor, 1); } read(); } else { int i = cursor; mark('}'); while (read() != '}') { } mark('\000'); int j = cursor; if (j > patternLength) throw error("Unclosed character family"); if (i + 1 >= j) throw error("Empty character family"); name = new String(temp, i, j - i - 1); } int i = name.indexOf('='); if (i != -1) { // property construct \p{name=value} String value = name.substring(i + 1); name = name.substring(0, i).toLowerCase(Locale.ENGLISH); switch (name) { case "sc": case "script": p = CharPredicates.forUnicodeScript(value); break; case "blk": case "block": p = CharPredicates.forUnicodeBlock(value); break; case "gc": case "general_category": p = CharPredicates.forProperty(value); break; default: break; } if (p == null) throw error("Unknown Unicode property {name=<" + name + ">, " + "value=<" + value + ">}"); } else { if (name.startsWith("In")) { // \p{InBlockName} p = CharPredicates.forUnicodeBlock(name.substring(2)); } else if (name.startsWith("Is")) { // \p{IsGeneralCategory} and \p{IsScriptName} name = name.substring(2); p = CharPredicates.forUnicodeProperty(name); if (p == null) p = CharPredicates.forProperty(name); if (p == null) p = CharPredicates.forUnicodeScript(name); } else { if (has(UNICODE_CHARACTER_CLASS)) { p = CharPredicates.forPOSIXName(name); } if (p == null) p = CharPredicates.forProperty(name); } if (p == null) throw error("Unknown character property name {In/Is" + name + "}"); } if (isComplement) { // it might be too expensive to detect if a complement of // CharProperty can match "certain" supplementary. So just // go with StartS. hasSupplementary = true; p = p.negate(); } return p; } private CharProperty newCharProperty(CharPredicate p) { if (p == null) return null; if (p instanceof BmpCharPredicate) return new BmpCharProperty((BmpCharPredicate) p); else return new CharProperty(p); } /** * Parses and returns the name of a "named capturing group", the trailing * ">" is consumed after parsing. */ private String groupname(int ch) { StringBuilder sb = new StringBuilder(); if (!ASCII.isAlpha(ch)) throw error("capturing group name does not start with a Latin letter"); do { sb.append((char) ch); } while (ASCII.isAlnum(ch = read())); if (ch != '>') throw error("named capturing group is missing trailing '>'"); return sb.toString(); } /** * Parses a group and returns the head node of a set of nodes that process * the group. Sometimes a double return system is used where the tail is * returned in root. */ private Node group0() { boolean capturingGroup = false; Node head; Node tail; int save = flags0; int saveTCNCount = topClosureNodes.size(); root = null; int ch = next(); if (ch == '?') { ch = skip(); switch (ch) { case ':': // (?:xxx) pure group head = createGroup(true); tail = root; head.next = expr(tail); break; case '=': // (?=xxx) and (?!xxx) lookahead case '!': head = createGroup(true); tail = root; head.next = expr(tail); if (ch == '=') { head = tail = new Pos(head); } else { head = tail = new Neg(head); } break; case '>': // (?>xxx) independent group head = createGroup(true); tail = root; head.next = expr(tail); head = tail = new Ques(head, Qtype.INDEPENDENT); break; case '<': // (?<xxx) look behind ch = read(); if (ch != '=' && ch != '!') { // named captured group String name = groupname(ch); if (namedGroups().containsKey(name)) throw error("Named capturing group <" + name + "> is already defined"); capturingGroup = true; head = createGroup(false); tail = root; namedGroups().put(name, capturingGroupCount - 1); head.next = expr(tail); break; } int start = cursor; head = createGroup(true); tail = root; head.next = expr(tail); tail.next = LookBehindEndNode.INSTANCE; TreeInfo info = new TreeInfo(); head.study(info); if (info.maxValid == false) { throw error("Look-behind group does not have " + "an obvious maximum length"); } boolean hasSupplementary = findSupplementary(start, patternLength); if (ch == '=') { head = tail = (hasSupplementary ? new BehindS(head, info.maxLength, info.minLength) : new Behind(head, info.maxLength, info.minLength)); } else { // if (ch == '!') head = tail = (hasSupplementary ? new NotBehindS(head, info.maxLength, info.minLength) : new NotBehind(head, info.maxLength, info.minLength)); } // clear all top-closure-nodes inside lookbehind if (saveTCNCount < topClosureNodes.size()) topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear(); break; case '$': case '@': throw error("Unknown group type"); default: // (?xxx:) inlined match flags unread(); addFlag(); ch = read(); if (ch == ')') { return null; // Inline modifier only } if (ch != ':') { throw error("Unknown inline modifier"); } head = createGroup(true); tail = root; head.next = expr(tail); break; } } else { // (xxx) a regular group capturingGroup = true; head = createGroup(false); tail = root; head.next = expr(tail); } accept(')', "Unclosed group"); flags0 = save; // Check for quantifiers Node node = closure(head); if (node == head) { // No closure root = tail; return node; // Dual return } if (head == tail) { // Zero length assertion root = node; return node; // Dual return } // have group closure, clear all inner closure nodes from the // top list (no backtracking stopper optimization for inner if (saveTCNCount < topClosureNodes.size()) topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear(); if (node instanceof Ques) { Ques ques = (Ques) node; if (ques.type == Qtype.POSSESSIVE) { root = node; return node; } tail.next = new BranchConn(); tail = tail.next; if (ques.type == Qtype.GREEDY) { head = new Branch(head, null, tail); } else { // Reluctant quantifier head = new Branch(null, head, tail); } root = tail; return head; } else if (node instanceof Curly) { Curly curly = (Curly) node; if (curly.type == Qtype.POSSESSIVE) { root = node; return node; } // Discover if the group is deterministic TreeInfo info = new TreeInfo(); if (head.study(info)) { // Deterministic GroupTail temp = (GroupTail) tail; head = root = new GroupCurly(head.next, curly.cmin, curly.cmax, curly.type, ((GroupTail) tail).localIndex, ((GroupTail) tail).groupIndex, capturingGroup); return head; } else { // Non-deterministic int temp = ((GroupHead) head).localIndex; Loop loop; if (curly.type == Qtype.GREEDY) { loop = new Loop(this.localCount, temp); // add the max_reps greedy to the top-closure-node list if (curly.cmax == MAX_REPS) topClosureNodes.add(loop); } else { // Reluctant Curly loop = new LazyLoop(this.localCount, temp); } Prolog prolog = new Prolog(loop); this.localCount += 1; loop.cmin = curly.cmin; loop.cmax = curly.cmax; loop.body = head; tail.next = loop; root = loop; return prolog; // Dual return } } throw error("Internal logic error"); } /** * Create group head and tail nodes using double return. If the group is * created with anonymous true then it is a pure group and should not * affect group counting. */ private Node createGroup(boolean anonymous) { int localIndex = localCount++; int groupIndex = 0; if (!anonymous) groupIndex = capturingGroupCount++; GroupHead head = new GroupHead(localIndex); root = new GroupTail(localIndex, groupIndex); // for debug/print only, head.match does NOT need the "tail" info head.tail = (GroupTail) root; if (!anonymous && groupIndex < 10) groupNodes[groupIndex] = head; return head; } @SuppressWarnings("fallthrough") /** * Parses inlined match flags and set them appropriately. */ private void addFlag() { int ch = peek(); for (;;) { switch (ch) { case 'i': flags0 |= CASE_INSENSITIVE; break; case 'm': flags0 |= MULTILINE; break; case 's': flags0 |= DOTALL; break; case 'd': flags0 |= UNIX_LINES; break; case 'u': flags0 |= UNICODE_CASE; break; case 'c': flags0 |= CANON_EQ; break; case 'x': flags0 |= COMMENTS; break; case 'U': flags0 |= (UNICODE_CHARACTER_CLASS | UNICODE_CASE); break; case '-': // subFlag then fall through ch = next(); subFlag(); default: return; } ch = next(); } } @SuppressWarnings("fallthrough") /** * Parses the second part of inlined match flags and turns off * flags appropriately. */ private void subFlag() { int ch = peek(); for (;;) { switch (ch) { case 'i': flags0 &= ~CASE_INSENSITIVE; break; case 'm': flags0 &= ~MULTILINE; break; case 's': flags0 &= ~DOTALL; break; case 'd': flags0 &= ~UNIX_LINES; break; case 'u': flags0 &= ~UNICODE_CASE; break; case 'c': flags0 &= ~CANON_EQ; break; case 'x': flags0 &= ~COMMENTS; break; case 'U': flags0 &= ~(UNICODE_CHARACTER_CLASS | UNICODE_CASE); break; default: return; } ch = next(); } } static final int MAX_REPS = 0x7FFFFFFF; static enum Qtype { GREEDY, LAZY, POSSESSIVE, INDEPENDENT } private Node curly(Node prev, int cmin) { int ch = next(); if (ch == '?') { next(); return new Curly(prev, cmin, MAX_REPS, Qtype.LAZY); } else if (ch == '+') { next(); return new Curly(prev, cmin, MAX_REPS, Qtype.POSSESSIVE); } if (prev instanceof BmpCharProperty) { return new BmpCharPropertyGreedy((BmpCharProperty) prev, cmin); } else if (prev instanceof CharProperty) { return new CharPropertyGreedy((CharProperty) prev, cmin); } return new Curly(prev, cmin, MAX_REPS, Qtype.GREEDY); } /** * Processes repetition. If the next character peeked is a quantifier * then new nodes must be appended to handle the repetition. * Prev could be a single or a group, so it could be a chain of nodes. */ private Node closure(Node prev) { int ch = peek(); switch (ch) { case '?': ch = next(); if (ch == '?') { next(); return new Ques(prev, Qtype.LAZY); } else if (ch == '+') { next(); return new Ques(prev, Qtype.POSSESSIVE); } return new Ques(prev, Qtype.GREEDY); case '*': return curly(prev, 0); case '+': return curly(prev, 1); case '{': ch = skip(); if (ASCII.isDigit(ch)) { int cmin = 0, cmax; try { do { cmin = Math.addExact(Math.multiplyExact(cmin, 10), ch - '0'); } while (ASCII.isDigit(ch = read())); if (ch == ',') { ch = read(); if (ch == '}') { unread(); return curly(prev, cmin); } else { cmax = 0; while (ASCII.isDigit(ch)) { cmax = Math.addExact(Math.multiplyExact(cmax, 10), ch - '0'); ch = read(); } } } else { cmax = cmin; } } catch (ArithmeticException ae) { throw error("Illegal repetition range"); } if (ch != '}') throw error("Unclosed counted closure"); if (cmax < cmin) throw error("Illegal repetition range"); ch = peek(); if (ch == '?') { next(); return new Curly(prev, cmin, cmax, Qtype.LAZY); } else if (ch == '+') { next(); return new Curly(prev, cmin, cmax, Qtype.POSSESSIVE); } else { return new Curly(prev, cmin, cmax, Qtype.GREEDY); } } else { throw error("Illegal repetition"); } default: return prev; } } /** * Utility method for parsing control escape sequences. */ private int c() { if (cursor < patternLength) { return read() ^ 64; } throw error("Illegal control escape sequence"); } /** * Utility method for parsing octal escape sequences. */ private int o() { int n = read(); if (((n - '0') | ('7' - n)) >= 0) { int m = read(); if (((m - '0') | ('7' - m)) >= 0) { int o = read(); if ((((o - '0') | ('7' - o)) >= 0) && (((n - '0') | ('3' - n)) >= 0)) { return (n - '0') * 64 + (m - '0') * 8 + (o - '0'); } unread(); return (n - '0') * 8 + (m - '0'); } unread(); return (n - '0'); } throw error("Illegal octal escape sequence"); } /** * Utility method for parsing hexadecimal escape sequences. */ private int x() { int n = read(); if (ASCII.isHexDigit(n)) { int m = read(); if (ASCII.isHexDigit(m)) { return ASCII.toDigit(n) * 16 + ASCII.toDigit(m); } } else if (n == '{' && ASCII.isHexDigit(peek())) { int ch = 0; while (ASCII.isHexDigit(n = read())) { ch = (ch << 4) + ASCII.toDigit(n); if (ch > Character.MAX_CODE_POINT) throw error("Hexadecimal codepoint is too big"); } if (n != '}') throw error("Unclosed hexadecimal escape sequence"); return ch; } throw error("Illegal hexadecimal escape sequence"); } /** * Utility method for parsing unicode escape sequences. */ private int cursor() { return cursor; } private void setcursor(int pos) { cursor = pos; } private int uxxxx() { int n = 0; for (int i = 0; i < 4; i++) { int ch = read(); if (!ASCII.isHexDigit(ch)) { throw error("Illegal Unicode escape sequence"); } n = n * 16 + ASCII.toDigit(ch); } return n; } private int u() { int n = uxxxx(); if (Character.isHighSurrogate((char) n)) { int cur = cursor(); if (read() == '\\' && read() == 'u') { int n2 = uxxxx(); if (Character.isLowSurrogate((char) n2)) return Character.toCodePoint((char) n, (char) n2); } setcursor(cur); } return n; } private int N() { if (read() == '{') { int i = cursor; while (cursor < patternLength && read() != '}') { } if (cursor > patternLength) throw error("Unclosed character name escape sequence"); String name = new String(temp, i, cursor - i - 1); try { return Character.codePointOf(name); } catch (IllegalArgumentException x) { throw error("Unknown character name [" + name + "]"); } } throw error("Illegal character name escape sequence"); } // // Utility methods for code point support // private static final int countChars(CharSequence seq, int index, int lengthInCodePoints) { // optimization if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) { assert (index >= 0 && index < seq.length()); return 1; } int length = seq.length(); int x = index; if (lengthInCodePoints >= 0) { assert (index >= 0 && index < length); for (int i = 0; x < length && i < lengthInCodePoints; i++) { if (Character.isHighSurrogate(seq.charAt(x++))) { if (x < length && Character.isLowSurrogate(seq.charAt(x))) { x++; } } } return x - index; } assert (index >= 0 && index <= length); if (index == 0) { return 0; } int len = -lengthInCodePoints; for (int i = 0; x > 0 && i < len; i++) { if (Character.isLowSurrogate(seq.charAt(--x))) { if (x > 0 && Character.isHighSurrogate(seq.charAt(x - 1))) { x--; } } } return index - x; } private static final int countCodePoints(CharSequence seq) { int length = seq.length(); int n = 0; for (int i = 0; i < length;) { n++; if (Character.isHighSurrogate(seq.charAt(i++))) { if (i < length && Character.isLowSurrogate(seq.charAt(i))) { i++; } } } return n; } /** * Creates a bit vector for matching Latin-1 values. A normal BitClass * never matches values above Latin-1, and a complemented BitClass always * matches values above Latin-1. */ static final class BitClass implements BmpCharPredicate { final boolean[] bits; BitClass() { bits = new boolean[256]; } BitClass add(int c, int flags) { assert c >= 0 && c <= 255; if ((flags & CASE_INSENSITIVE) != 0) { if (ASCII.isAscii(c)) { bits[ASCII.toUpper(c)] = true; bits[ASCII.toLower(c)] = true; } else if ((flags & UNICODE_CASE) != 0) { bits[Character.toLowerCase(c)] = true; bits[Character.toUpperCase(c)] = true; } } bits[c] = true; return this; } public boolean is(int ch) { return ch < 256 && bits[ch]; } } /** * Utility method for creating a string slice matcher. */ private Node newSlice(int[] buf, int count, boolean hasSupplementary) { int[] tmp = new int[count]; if (has(CASE_INSENSITIVE)) { if (has(UNICODE_CASE)) { for (int i = 0; i < count; i++) { tmp[i] = Character.toLowerCase(Character.toUpperCase(buf[i])); } return hasSupplementary ? new SliceUS(tmp) : new SliceU(tmp); } for (int i = 0; i < count; i++) { tmp[i] = ASCII.toLower(buf[i]); } return hasSupplementary ? new SliceIS(tmp) : new SliceI(tmp); } for (int i = 0; i < count; i++) { tmp[i] = buf[i]; } return hasSupplementary ? new SliceS(tmp) : new Slice(tmp); } /** * The following classes are the building components of the object * tree that represents a compiled regular expression. The object tree * is made of individual elements that handle constructs in the Pattern. * Each type of object knows how to match its equivalent construct with * the match() method. */ /** * Base class for all node classes. Subclasses should override the match() * method as appropriate. This class is an accepting node, so its match() * always returns true. */ static class Node extends Object { Node next; Node() { next = Pattern.accept; } /** * This method implements the classic accept node. */ boolean match(Matcher matcher, int i, CharSequence seq) { matcher.last = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } /** * This method is good for all zero length assertions. */ boolean study(TreeInfo info) { if (next != null) { return next.study(info); } else { return info.deterministic; } } } static class LastNode extends Node { /** * This method implements the classic accept node with * the addition of a check to see if the match occurred * using all of the input. */ boolean match(Matcher matcher, int i, CharSequence seq) { if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to) return false; matcher.last = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } } /** * Used for REs that can start anywhere within the input string. * This basically tries to match repeatedly at each spot in the * input string, moving forward after each try. An anchored search * or a BnM will bypass this node completely. */ static class Start extends Node { int minLength; Start(Node node) { this.next = node; TreeInfo info = new TreeInfo(); next.study(info); minLength = info.minLength; } boolean match(Matcher matcher, int i, CharSequence seq) { if (i > matcher.to - minLength) { matcher.hitEnd = true; return false; } int guard = matcher.to - minLength; for (; i <= guard; i++) { if (next.match(matcher, i, seq)) { matcher.first = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } } matcher.hitEnd = true; return false; } boolean study(TreeInfo info) { next.study(info); info.maxValid = false; info.deterministic = false; return false; } } /* * StartS supports supplementary characters, including unpaired surrogates. */ static final class StartS extends Start { StartS(Node node) { super(node); } boolean match(Matcher matcher, int i, CharSequence seq) { if (i > matcher.to - minLength) { matcher.hitEnd = true; return false; } int guard = matcher.to - minLength; while (i <= guard) { //if ((ret = next.match(matcher, i, seq)) || i == guard) if (next.match(matcher, i, seq)) { matcher.first = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } if (i == guard) break; // Optimization to move to the next character. This is // faster than countChars(seq, i, 1). if (Character.isHighSurrogate(seq.charAt(i++))) { if (i < seq.length() && Character.isLowSurrogate(seq.charAt(i))) { i++; } } } matcher.hitEnd = true; return false; } } /** * Node to anchor at the beginning of input. This object implements the * match for a \A sequence, and the caret anchor will use this if not in * multiline mode. */ static final class Begin extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { int fromIndex = (matcher.anchoringBounds) ? matcher.from : 0; if (i == fromIndex && next.match(matcher, i, seq)) { matcher.first = i; matcher.groups[0] = i; matcher.groups[1] = matcher.last; return true; } else { return false; } } } /** * Node to anchor at the end of input. This is the absolute end, so this * should not match at the last newline before the end as $ will. */ static final class End extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { int endIndex = (matcher.anchoringBounds) ? matcher.to : matcher.getTextLength(); if (i == endIndex) { matcher.hitEnd = true; return next.match(matcher, i, seq); } return false; } } /** * Node to anchor at the beginning of a line. This is essentially the * object to match for the multiline ^. */ static final class Caret extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { int startIndex = matcher.from; int endIndex = matcher.to; if (!matcher.anchoringBounds) { startIndex = 0; endIndex = matcher.getTextLength(); } // Perl does not match ^ at end of input even after newline if (i == endIndex) { matcher.hitEnd = true; return false; } if (i > startIndex) { char ch = seq.charAt(i - 1); if (ch != '\n' && ch != '\r' && (ch | 1) != '\u2029' && ch != '\u0085') { return false; } // Should treat /r/n as one newline if (ch == '\r' && seq.charAt(i) == '\n') return false; } return next.match(matcher, i, seq); } } /** * Node to anchor at the beginning of a line when in unixdot mode. */ static final class UnixCaret extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { int startIndex = matcher.from; int endIndex = matcher.to; if (!matcher.anchoringBounds) { startIndex = 0; endIndex = matcher.getTextLength(); } // Perl does not match ^ at end of input even after newline if (i == endIndex) { matcher.hitEnd = true; return false; } if (i > startIndex) { char ch = seq.charAt(i - 1); if (ch != '\n') { return false; } } return next.match(matcher, i, seq); } } /** * Node to match the location where the last match ended. * This is used for the \G construct. */ static final class LastMatch extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { if (i != matcher.oldLast) return false; return next.match(matcher, i, seq); } } /** * Node to anchor at the end of a line or the end of input based on the * multiline mode. * * When not in multiline mode, the $ can only match at the very end * of the input, unless the input ends in a line terminator in which * it matches right before the last line terminator. * * Note that \r\n is considered an atomic line terminator. * * Like ^ the $ operator matches at a position, it does not match the * line terminators themselves. */ static final class Dollar extends Node { boolean multiline; Dollar(boolean mul) { multiline = mul; } boolean match(Matcher matcher, int i, CharSequence seq) { int endIndex = (matcher.anchoringBounds) ? matcher.to : matcher.getTextLength(); if (!multiline) { if (i < endIndex - 2) return false; if (i == endIndex - 2) { char ch = seq.charAt(i); if (ch != '\r') return false; ch = seq.charAt(i + 1); if (ch != '\n') return false; } } // Matches before any line terminator; also matches at the // end of input // Before line terminator: // If multiline, we match here no matter what // If not multiline, fall through so that the end // is marked as hit; this must be a /r/n or a /n // at the very end so the end was hit; more input // could make this not match here if (i < endIndex) { char ch = seq.charAt(i); if (ch == '\n') { // No match between \r\n if (i > 0 && seq.charAt(i - 1) == '\r') return false; if (multiline) return next.match(matcher, i, seq); } else if (ch == '\r' || ch == '\u0085' || (ch | 1) == '\u2029') { if (multiline) return next.match(matcher, i, seq); } else { // No line terminator, no match return false; } } // Matched at current end so hit end matcher.hitEnd = true; // If a $ matches because of end of input, then more input // could cause it to fail! matcher.requireEnd = true; return next.match(matcher, i, seq); } boolean study(TreeInfo info) { next.study(info); return info.deterministic; } } /** * Node to anchor at the end of a line or the end of input based on the * multiline mode when in unix lines mode. */ static final class UnixDollar extends Node { boolean multiline; UnixDollar(boolean mul) { multiline = mul; } boolean match(Matcher matcher, int i, CharSequence seq) { int endIndex = (matcher.anchoringBounds) ? matcher.to : matcher.getTextLength(); if (i < endIndex) { char ch = seq.charAt(i); if (ch == '\n') { // If not multiline, then only possible to // match at very end or one before end if (multiline == false && i != endIndex - 1) return false; // If multiline return next.match without setting // matcher.hitEnd if (multiline) return next.match(matcher, i, seq); } else { return false; } } // Matching because at the end or 1 before the end; // more input could change this so set hitEnd matcher.hitEnd = true; // If a $ matches because of end of input, then more input // could cause it to fail! matcher.requireEnd = true; return next.match(matcher, i, seq); } boolean study(TreeInfo info) { next.study(info); return info.deterministic; } } /** * Node class that matches a Unicode line ending '\R' */ static final class LineEnding extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { // (u+000Du+000A|[u+000Au+000Bu+000Cu+000Du+0085u+2028u+2029]) if (i < matcher.to) { int ch = seq.charAt(i); if (ch == 0x0A || ch == 0x0B || ch == 0x0C || ch == 0x85 || ch == 0x2028 || ch == 0x2029) return next.match(matcher, i + 1, seq); if (ch == 0x0D) { i++; if (i < matcher.to) { if (seq.charAt(i) == 0x0A && next.match(matcher, i + 1, seq)) { return true; } } else { matcher.hitEnd = true; } return next.match(matcher, i, seq); } } else { matcher.hitEnd = true; } return false; } boolean study(TreeInfo info) { info.minLength++; info.maxLength += 2; return next.study(info); } } /** * Abstract node class to match one character satisfying some * boolean property. */ static class CharProperty extends Node { final CharPredicate predicate; CharProperty(CharPredicate predicate) { this.predicate = predicate; } boolean match(Matcher matcher, int i, CharSequence seq) { if (i < matcher.to) { int ch = Character.codePointAt(seq, i); return predicate.is(ch) && next.match(matcher, i + Character.charCount(ch), seq); } else { matcher.hitEnd = true; return false; } } boolean study(TreeInfo info) { info.minLength++; info.maxLength++; return next.study(info); } } /** * Optimized version of CharProperty that works only for * properties never satisfied by Supplementary characters. */ private static class BmpCharProperty extends CharProperty { BmpCharProperty(BmpCharPredicate predicate) { super(predicate); } boolean match(Matcher matcher, int i, CharSequence seq) { if (i < matcher.to) { return predicate.is(seq.charAt(i)) && next.match(matcher, i + 1, seq); } else { matcher.hitEnd = true; return false; } } } private static class NFCCharProperty extends Node { CharPredicate predicate; NFCCharProperty(CharPredicate predicate) { this.predicate = predicate; } boolean match(Matcher matcher, int i, CharSequence seq) { if (i < matcher.to) { int ch0 = Character.codePointAt(seq, i); int n = Character.charCount(ch0); int j = i + n; // Fast check if it's necessary to call Normalizer; // testing Grapheme.isBoundary is enough for this case while (j < matcher.to) { int ch1 = Character.codePointAt(seq, j); if (Grapheme.isBoundary(ch0, ch1)) break; ch0 = ch1; j += Character.charCount(ch1); } if (i + n == j) { // single, assume nfc cp if (predicate.is(ch0)) return next.match(matcher, j, seq); } else { while (i + n < j) { String nfc = Normalizer.normalize(seq.toString().substring(i, j), Normalizer.Form.NFC); if (nfc.codePointCount(0, nfc.length()) == 1) { if (predicate.is(nfc.codePointAt(0)) && next.match(matcher, j, seq)) { return true; } } ch0 = Character.codePointBefore(seq, j); j -= Character.charCount(ch0); } } if (j < matcher.to) return false; } matcher.hitEnd = true; return false; } boolean study(TreeInfo info) { info.minLength++; info.deterministic = false; return next.study(info); } } /** * Node class that matches an unicode extended grapheme cluster */ static class XGrapheme extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { if (i < matcher.to) { i = Grapheme.nextBoundary(seq, i, matcher.to); return next.match(matcher, i, seq); } matcher.hitEnd = true; return false; } boolean study(TreeInfo info) { info.minLength++; info.deterministic = false; return next.study(info); } } /** * Node class that handles grapheme boundaries */ static class GraphemeBound extends Node { boolean match(Matcher matcher, int i, CharSequence seq) { int startIndex = matcher.from; int endIndex = matcher.to; if (matcher.transparentBounds) { startIndex = 0; endIndex = matcher.getTextLength(); } if (i == startIndex) { return next.match(matcher, i, seq); } if (i < endIndex) { if (Character.isSurrogatePair(seq.charAt(i - 1), seq.charAt(i)) || Grapheme.nextBoundary(seq, i - Character.charCount(Character.codePointBefore(seq, i)), i + Character.charCount(Character.codePointAt(seq, i))) > i) { return false; } } else { matcher.hitEnd = true; matcher.requireEnd = true; } return next.match(matcher, i, seq); } } /** * Base class for all Slice nodes */ static class SliceNode extends Node { int[] buffer; SliceNode(int[] buf) { buffer = buf; } boolean study(TreeInfo info) { info.minLength += buffer.length; info.maxLength += buffer.length; return next.study(info); } } /** * Node class for a case sensitive/BMP-only sequence of literal * characters. */ static class Slice extends SliceNode { Slice(int[] buf) { super(buf); } boolean match(Matcher matcher, int i, CharSequence seq) { int[] buf = buffer; int len = buf.length; for (int j = 0; j < len; j++) { if ((i + j) >= matcher.to) { matcher.hitEnd = true; return false; } if (buf[j] != seq.charAt(i + j)) return false; } return next.match(matcher, i + len, seq); } } /** * Node class for a case_insensitive/BMP-only sequence of literal * characters. */ static class SliceI extends SliceNode { SliceI(int[] buf) { super(buf); } boolean match(Matcher matcher, int i, CharSequence seq) { int[] buf = buffer; int len = buf.length; for (int j = 0; j < len; j++) { if ((i + j) >= matcher.to) { matcher.hitEnd = true; return false; } int c = seq.charAt(i + j); if (buf[j] != c && buf[j] != ASCII.toLower(c)) return false; } return next.match(matcher, i + len, seq); } } /** * Node class for a unicode_case_insensitive/BMP-only sequence of * literal characters. Uses unicode case folding. */ static final class SliceU extends SliceNode { SliceU(int[] buf) { super(buf); } boolean match(Matcher matcher, int i, CharSequence seq) { int[] buf = buffer; int len = buf.length; for (int j = 0; j < len; j++) { if ((i + j) >= matcher.to) { matcher.hitEnd = true; return false; } int c = seq.charAt(i + j); if (buf[j] != c && buf[j] != Character.toLowerCase(Character.toUpperCase(c))) return false; } return next.match(matcher, i + len, seq); } } /** * Node class for a case sensitive sequence of literal characters * including supplementary characters. */ static final class SliceS extends Slice { SliceS(int[] buf) { super(buf); } boolean match(Matcher matcher, int i, CharSequence seq) { int[] buf = buffer; int x = i; for (int j = 0; j < buf.length; j++) { if (x >= matcher.to) { matcher.hitEnd = true; return false; } int c = Character.codePointAt(seq, x); if (buf[j] != c) return false; x += Character.charCount(c); if (x > matcher.to) { matcher.hitEnd = true; return false; } } return next.match(matcher, x, seq); } } /** * Node class for a case insensitive sequence of literal characters * including supplementary characters. */ static class SliceIS extends SliceNode { SliceIS(int[] buf) { super(buf); } int toLower(int c) { return ASCII.toLower(c); } boolean match(Matcher matcher, int i, CharSequence seq) { int[] buf = buffer; int x = i; for (int j = 0; j < buf.length; j++) { if (x >= matcher.to) { matcher.hitEnd = true; return false; } int c = Character.codePointAt(seq, x); if (buf[j] != c && buf[j] != toLower(c)) return false; x += Character.charCount(c); if (x > matcher.to) { matcher.hitEnd = true; return false; } } return next.match(matcher, x, seq); } } /** * Node class for a case insensitive sequence of literal characters. * Uses unicode case folding. */ static final class SliceUS extends SliceIS { SliceUS(int[] buf) { super(buf); } int toLower(int c) { return Character.toLowerCase(Character.toUpperCase(c)); } } /** * The 0 or 1 quantifier. This one class implements all three types. */ static final class Ques extends Node { Node atom; Qtype type; Ques(Node node, Qtype type) { this.atom = node; this.type = type; } boolean match(Matcher matcher, int i, CharSequence seq) { switch (type) { case GREEDY: return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq)) || next.match(matcher, i, seq); case LAZY: return next.match(matcher, i, seq) || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq)); case POSSESSIVE: if (atom.match(matcher, i, seq)) i = matcher.last; return next.match(matcher, i, seq); default: return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq); } } boolean study(TreeInfo info) { if (type != Qtype.INDEPENDENT) { int minL = info.minLength; atom.study(info); info.minLength = minL; info.deterministic = false; return next.study(info); } else { atom.study(info); return next.study(info); } } } /** * Handles the greedy style repetition with the specified minimum * and the maximum equal to MAX_REPS, for *, + and {N,} quantifiers. */ static class CharPropertyGreedy extends Node { final CharPredicate predicate; final int cmin; CharPropertyGreedy(CharProperty cp, int cmin) { this.predicate = cp.predicate; this.cmin = cmin; } boolean match(Matcher matcher, int i, CharSequence seq) { int n = 0; int to = matcher.to; // greedy, all the way down while (i < to) { int ch = Character.codePointAt(seq, i); if (!predicate.is(ch)) break; i += Character.charCount(ch); n++; } if (i >= to) { matcher.hitEnd = true; } while (n >= cmin) { if (next.match(matcher, i, seq)) return true; if (n == cmin) return false; // backing off if match fails int ch = Character.codePointBefore(seq, i); i -= Character.charCount(ch); n--; } return false; } boolean study(TreeInfo info) { info.minLength += cmin; if (info.maxValid) { info.maxLength += MAX_REPS; } info.deterministic = false; return next.study(info); } } static final class BmpCharPropertyGreedy extends CharPropertyGreedy { BmpCharPropertyGreedy(BmpCharProperty bcp, int cmin) { super(bcp, cmin); } boolean match(Matcher matcher, int i, CharSequence seq) { int n = 0; int to = matcher.to; while (i < to && predicate.is(seq.charAt(i))) { i++; n++; } if (i >= to) { matcher.hitEnd = true; } while (n >= cmin) { if (next.match(matcher, i, seq)) return true; i--; n--; // backing off if match fails } return false; } } /** * Handles the curly-brace style repetition with a specified minimum and * maximum occurrences. The * quantifier is handled as a special case. * This class handles the three types. */ static final class Curly extends Node { Node atom; Qtype type; int cmin; int cmax; Curly(Node node, int cmin, int cmax, Qtype type) { this.atom = node; this.type = type; this.cmin = cmin; this.cmax = cmax; } boolean match(Matcher matcher, int i, CharSequence seq) { int j; for (j = 0; j < cmin; j++) { if (atom.match(matcher, i, seq)) { i = matcher.last; continue; } return false; } if (type == Qtype.GREEDY) return match0(matcher, i, j, seq); else if (type == Qtype.LAZY) return match1(matcher, i, j, seq); else return match2(matcher, i, j, seq); } // Greedy match. // i is the index to start matching at // j is the number of atoms that have matched boolean match0(Matcher matcher, int i, int j, CharSequence seq) { if (j >= cmax) { // We have matched the maximum... continue with the rest of // the regular expression return next.match(matcher, i, seq); } int backLimit = j; while (atom.match(matcher, i, seq)) { // k is the length of this match int k = matcher.last - i; if (k == 0) // Zero length match break; // Move up index and number matched i = matcher.last; j++; // We are greedy so match as many as we can while (j < cmax) { if (!atom.match(matcher, i, seq)) break; if (i + k != matcher.last) { if (match0(matcher, matcher.last, j + 1, seq)) return true; break; } i += k; j++; } // Handle backing off if match fails while (j >= backLimit) { if (next.match(matcher, i, seq)) return true; i -= k; j--; } return false; } return next.match(matcher, i, seq); } // Reluctant match. At this point, the minimum has been satisfied. // i is the index to start matching at // j is the number of atoms that have matched boolean match1(Matcher matcher, int i, int j, CharSequence seq) { for (;;) { // Try finishing match without consuming any more if (next.match(matcher, i, seq)) return true; // At the maximum, no match found if (j >= cmax) return false; // Okay, must try one more atom if (!atom.match(matcher, i, seq)) return false; // If we haven't moved forward then must break out if (i == matcher.last) return false; // Move up index and number matched i = matcher.last; j++; } } boolean match2(Matcher matcher, int i, int j, CharSequence seq) { for (; j < cmax; j++) { if (!atom.match(matcher, i, seq)) break; if (i == matcher.last) break; i = matcher.last; } return next.match(matcher, i, seq); } boolean study(TreeInfo info) { // Save original info int minL = info.minLength; int maxL = info.maxLength; boolean maxV = info.maxValid; boolean detm = info.deterministic; info.reset(); atom.study(info); int temp = info.minLength * cmin + minL; if (temp < minL) { temp = 0xFFFFFFF; // arbitrary large number } info.minLength = temp; if (maxV & info.maxValid) { temp = info.maxLength * cmax + maxL; info.maxLength = temp; if (temp < maxL) { info.maxValid = false; } } else { info.maxValid = false; } if (info.deterministic && cmin == cmax) info.deterministic = detm; else info.deterministic = false; return next.study(info); } } /** * Handles the curly-brace style repetition with a specified minimum and * maximum occurrences in deterministic cases. This is an iterative * optimization over the Prolog and Loop system which would handle this * in a recursive way. The * quantifier is handled as a special case. * If capture is true then this class saves group settings and ensures * that groups are unset when backing off of a group match. */ static final class GroupCurly extends Node { Node atom; Qtype type; int cmin; int cmax; int localIndex; int groupIndex; boolean capture; GroupCurly(Node node, int cmin, int cmax, Qtype type, int local, int group, boolean capture) { this.atom = node; this.type = type; this.cmin = cmin; this.cmax = cmax; this.localIndex = local; this.groupIndex = group; this.capture = capture; } boolean match(Matcher matcher, int i, CharSequence seq) { int[] groups = matcher.groups; int[] locals = matcher.locals; int save0 = locals[localIndex]; int save1 = 0; int save2 = 0; if (capture) { save1 = groups[groupIndex]; save2 = groups[groupIndex + 1]; } // Notify GroupTail there is no need to setup group info // because it will be set here locals[localIndex] = -1; boolean ret = true; for (int j = 0; j < cmin; j++) { if (atom.match(matcher, i, seq)) { if (capture) { groups[groupIndex] = i; groups[groupIndex + 1] = matcher.last; } i = matcher.last; } else { ret = false; break; } } if (ret) { if (type == Qtype.GREEDY) { ret = match0(matcher, i, cmin, seq); } else if (type == Qtype.LAZY) { ret = match1(matcher, i, cmin, seq); } else { ret = match2(matcher, i, cmin, seq); } } if (!ret) { locals[localIndex] = save0; if (capture) { groups[groupIndex] = save1; groups[groupIndex + 1] = save2; } } return ret; } // Aggressive group match boolean match0(Matcher matcher, int i, int j, CharSequence seq) { // don't back off passing the starting "j" int min = j; int[] groups = matcher.groups; int save0 = 0; int save1 = 0; if (capture) { save0 = groups[groupIndex]; save1 = groups[groupIndex + 1]; } for (;;) { if (j >= cmax) break; if (!atom.match(matcher, i, seq)) break; int k = matcher.last - i; if (k <= 0) { if (capture) { groups[groupIndex] = i; groups[groupIndex + 1] = i + k; } i = i + k; break; } for (;;) { if (capture) { groups[groupIndex] = i; groups[groupIndex + 1] = i + k; } i = i + k; if (++j >= cmax) break; if (!atom.match(matcher, i, seq)) break; if (i + k != matcher.last) { if (match0(matcher, i, j, seq)) return true; break; } } while (j > min) { if (next.match(matcher, i, seq)) { if (capture) { groups[groupIndex + 1] = i; groups[groupIndex] = i - k; } return true; } // backing off i = i - k; if (capture) { groups[groupIndex + 1] = i; groups[groupIndex] = i - k; } j--; } break; } if (capture) { groups[groupIndex] = save0; groups[groupIndex + 1] = save1; } return next.match(matcher, i, seq); } // Reluctant matching boolean match1(Matcher matcher, int i, int j, CharSequence seq) { for (;;) { if (next.match(matcher, i, seq)) return true; if (j >= cmax) return false; if (!atom.match(matcher, i, seq)) return false; if (i == matcher.last) return false; if (capture) { matcher.groups[groupIndex] = i; matcher.groups[groupIndex + 1] = matcher.last; } i = matcher.last; j++; } } // Possessive matching boolean match2(Matcher matcher, int i, int j, CharSequence seq) { for (; j < cmax; j++) { if (!atom.match(matcher, i, seq)) { break; } if (capture) { matcher.groups[groupIndex] = i; matcher.groups[groupIndex + 1] = matcher.last; } if (i == matcher.last) { break; } i = matcher.last; } return next.match(matcher, i, seq); } boolean study(TreeInfo info) { // Save original info int minL = info.minLength; int maxL = info.maxLength; boolean maxV = info.maxValid; boolean detm = info.deterministic; info.reset(); atom.study(info); int temp = info.minLength * cmin + minL; if (temp < minL) { temp = 0xFFFFFFF; // Arbitrary large number } info.minLength = temp; if (maxV & info.maxValid) { temp = info.maxLength * cmax + maxL; info.maxLength = temp; if (temp < maxL) { info.maxValid = false; } } else { info.maxValid = false; } if (info.deterministic && cmin == cmax) { info.deterministic = detm; } else { info.deterministic = false; } return next.study(info); } } /** * A Guard node at the end of each atom node in a Branch. It * serves the purpose of chaining the "match" operation to * "next" but not the "study", so we can collect the TreeInfo * of each atom node without including the TreeInfo of the * "next". */ static final class BranchConn extends Node { BranchConn() { } boolean match(Matcher matcher, int i, CharSequence seq) { return next.match(matcher, i, seq); } boolean study(TreeInfo info) { return info.deterministic; } } /** * Handles the branching of alternations. Note this is also used for * the ? quantifier to branch between the case where it matches once * and where it does not occur. */ static final class Branch extends Node { Node[] atoms = new Node[2]; int size = 2; Node conn; Branch(Node first, Node second, Node branchConn) { conn = branchConn; atoms[0] = first; atoms[1] = second; } void add(Node node) { if (size >= atoms.length) { Node[] tmp = new Node[atoms.length * 2]; System.arraycopy(atoms, 0, tmp, 0, atoms.length); atoms = tmp; } atoms[size++] = node; } boolean match(Matcher matcher, int i, CharSequence seq) { for (int n = 0; n < size; n++) { if (atoms[n] == null) { if (conn.next.match(matcher, i, seq)) return true; } else if (atoms[n].match(matcher, i, seq)) { return true; } } return false; } boolean study(TreeInfo info) { int minL = info.minLength; int maxL = info.maxLength; boolean maxV = info.maxValid; int minL2 = Integer.MAX_VALUE; //arbitrary large enough num int maxL2 = -1; for (int n = 0; n < size; n++) { info.reset(); if (atoms[n] != null) atoms[n].study(info); minL2 = Math.min(minL2, info.minLength); maxL2 = Math.max(maxL2, info.maxLength); maxV = (maxV & info.maxValid); } minL += minL2; maxL += maxL2; info.reset(); conn.next.study(info); info.minLength += minL; info.maxLength += maxL; info.maxValid &= maxV; info.deterministic = false; return false; } } /** * The GroupHead saves the location where the group begins in the locals * and restores them when the match is done. * * The matchRef is used when a reference to this group is accessed later * in the expression. The locals will have a negative value in them to * indicate that we do not want to unset the group if the reference * doesn't match. */ static final class GroupHead extends Node { int localIndex; GroupTail tail; // for debug/print only, match does not need to know GroupHead(int localCount) { localIndex = localCount; } boolean match(Matcher matcher, int i, CharSequence seq) { int save = matcher.locals[localIndex]; matcher.locals[localIndex] = i; boolean ret = next.match(matcher, i, seq); matcher.locals[localIndex] = save; return ret; } } /** * The GroupTail handles the setting of group beginning and ending * locations when groups are successfully matched. It must also be able to * unset groups that have to be backed off of. * * The GroupTail node is also used when a previous group is referenced, * and in that case no group information needs to be set. */ static final class GroupTail extends Node { int localIndex; int groupIndex; GroupTail(int localCount, int groupCount) { localIndex = localCount; groupIndex = groupCount + groupCount; } boolean match(Matcher matcher, int i, CharSequence seq) { int tmp = matcher.locals[localIndex]; if (tmp >= 0) { // This is the normal group case. // Save the group so we can unset it if it // backs off of a match. int groupStart = matcher.groups[groupIndex]; int groupEnd = matcher.groups[groupIndex + 1]; matcher.groups[groupIndex] = tmp; matcher.groups[groupIndex + 1] = i; if (next.match(matcher, i, seq)) { return true; } matcher.groups[groupIndex] = groupStart; matcher.groups[groupIndex + 1] = groupEnd; return false; } else { // This is a group reference case. We don't need to save any // group info because it isn't really a group. matcher.last = i; return true; } } } /** * This sets up a loop to handle a recursive quantifier structure. */ static final class Prolog extends Node { Loop loop; Prolog(Loop loop) { this.loop = loop; } boolean match(Matcher matcher, int i, CharSequence seq) { return loop.matchInit(matcher, i, seq); } boolean study(TreeInfo info) { return loop.study(info); } } /** * Handles the repetition count for a greedy Curly. The matchInit * is called from the Prolog to save the index of where the group * beginning is stored. A zero length group check occurs in the * normal match but is skipped in the matchInit. */ static class Loop extends Node { Node body; int countIndex; // local count index in matcher locals int beginIndex; // group beginning index int cmin, cmax; int posIndex; Loop(int countIndex, int beginIndex) { this.countIndex = countIndex; this.beginIndex = beginIndex; this.posIndex = -1; } boolean match(Matcher matcher, int i, CharSequence seq) { // Avoid infinite loop in zero-length case. if (i > matcher.locals[beginIndex]) { int count = matcher.locals[countIndex]; // This block is for before we reach the minimum // iterations required for the loop to match if (count < cmin) { matcher.locals[countIndex] = count + 1; boolean b = body.match(matcher, i, seq); // If match failed we must backtrack, so // the loop count should NOT be incremented if (!b) matcher.locals[countIndex] = count; // Return success or failure since we are under // minimum return b; } // This block is for after we have the minimum // iterations required for the loop to match if (count < cmax) { // Let's check if we have already tried and failed // at this starting position "i" in the past. // If yes, then just return false wihtout trying // again, to stop the exponential backtracking. if (posIndex != -1 && matcher.localsPos[posIndex].contains(i)) { return next.match(matcher, i, seq); } matcher.locals[countIndex] = count + 1; boolean b = body.match(matcher, i, seq); // If match failed we must backtrack, so // the loop count should NOT be incremented if (b) return true; matcher.locals[countIndex] = count; // save the failed position if (posIndex != -1) { matcher.localsPos[posIndex].add(i); } } } return next.match(matcher, i, seq); } boolean matchInit(Matcher matcher, int i, CharSequence seq) { int save = matcher.locals[countIndex]; boolean ret; if (posIndex != -1 && matcher.localsPos[posIndex] == null) { matcher.localsPos[posIndex] = new IntHashSet(); } if (0 < cmin) { matcher.locals[countIndex] = 1; ret = body.match(matcher, i, seq); } else if (0 < cmax) { matcher.locals[countIndex] = 1; ret = body.match(matcher, i, seq); if (ret == false) ret = next.match(matcher, i, seq); } else { ret = next.match(matcher, i, seq); } matcher.locals[countIndex] = save; return ret; } boolean study(TreeInfo info) { info.maxValid = false; info.deterministic = false; return false; } } /** * Handles the repetition count for a reluctant Curly. The matchInit * is called from the Prolog to save the index of where the group * beginning is stored. A zero length group check occurs in the * normal match but is skipped in the matchInit. */ static final class LazyLoop extends Loop { LazyLoop(int countIndex, int beginIndex) { super(countIndex, beginIndex); } boolean match(Matcher matcher, int i, CharSequence seq) { // Check for zero length group if (i > matcher.locals[beginIndex]) { int count = matcher.locals[countIndex]; if (count < cmin) { matcher.locals[countIndex] = count + 1; boolean result = body.match(matcher, i, seq); // If match failed we must backtrack, so // the loop count should NOT be incremented if (!result) matcher.locals[countIndex] = count; return result; } if (next.match(matcher, i, seq)) return true; if (count < cmax) { matcher.locals[countIndex] = count + 1; boolean result = body.match(matcher, i, seq); // If match failed we must backtrack, so // the loop count should NOT be incremented if (!result) matcher.locals[countIndex] = count; return result; } return false; } return next.match(matcher, i, seq); } boolean matchInit(Matcher matcher, int i, CharSequence seq) { int save = matcher.locals[countIndex]; boolean ret = false; if (0 < cmin) { matcher.locals[countIndex] = 1; ret = body.match(matcher, i, seq); } else if (next.match(matcher, i, seq)) { ret = true; } else if (0 < cmax) { matcher.locals[countIndex] = 1; ret = body.match(matcher, i, seq); } matcher.locals[countIndex] = save; return ret; } boolean study(TreeInfo info) { info.maxValid = false; info.deterministic = false; return false; } } /** * Refers to a group in the regular expression. Attempts to match * whatever the group referred to last matched. */ static class BackRef extends Node { int groupIndex; BackRef(int groupCount) { super(); groupIndex = groupCount + groupCount; } boolean match(Matcher matcher, int i, CharSequence seq) { int j = matcher.groups[groupIndex]; int k = matcher.groups[groupIndex + 1]; int groupSize = k - j; // If the referenced group didn't match, neither can this if (j < 0) return false; // If there isn't enough input left no match if (i + groupSize > matcher.to) { matcher.hitEnd = true; return false; } // Check each new char to make sure it matches what the group // referenced matched last time around for (int index = 0; index < groupSize; index++) if (seq.charAt(i + index) != seq.charAt(j + index)) return false; return next.match(matcher, i + groupSize, seq); } boolean study(TreeInfo info) { info.maxValid = false; return next.study(info); } } static class CIBackRef extends Node { int groupIndex; boolean doUnicodeCase; CIBackRef(int groupCount, boolean doUnicodeCase) { super(); groupIndex = groupCount + groupCount; this.doUnicodeCase = doUnicodeCase; } boolean match(Matcher matcher, int i, CharSequence seq) { int j = matcher.groups[groupIndex]; int k = matcher.groups[groupIndex + 1]; int groupSize = k - j; // If the referenced group didn't match, neither can this if (j < 0) return false; // If there isn't enough input left no match if (i + groupSize > matcher.to) { matcher.hitEnd = true; return false; } // Check each new char to make sure it matches what the group // referenced matched last time around int x = i; for (int index = 0; index < groupSize; index++) { int c1 = Character.codePointAt(seq, x); int c2 = Character.codePointAt(seq, j); if (c1 != c2) { if (doUnicodeCase) { int cc1 = Character.toUpperCase(c1); int cc2 = Character.toUpperCase(c2); if (cc1 != cc2 && Character.toLowerCase(cc1) != Character.toLowerCase(cc2)) return false; } else { if (ASCII.toLower(c1) != ASCII.toLower(c2)) return false; } } x += Character.charCount(c1); j += Character.charCount(c2); } return next.match(matcher, i + groupSize, seq); } boolean study(TreeInfo info) { info.maxValid = false; return next.study(info); } } /** * Searches until the next instance of its atom. This is useful for * finding the atom efficiently without passing an instance of it * (greedy problem) and without a lot of wasted search time (reluctant * problem). */ static final class First extends Node { Node atom; First(Node node) { this.atom = BnM.optimize(node); } boolean match(Matcher matcher, int i, CharSequence seq) { if (atom instanceof BnM) { return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq); } for (;;) { if (i > matcher.to) { matcher.hitEnd = true; return false; } if (atom.match(matcher, i, seq)) { return next.match(matcher, matcher.last, seq); } i += countChars(seq, i, 1); matcher.first++; } } boolean study(TreeInfo info) { atom.study(info); info.maxValid = false; info.deterministic = false; return next.study(info); } } /** * Zero width positive lookahead. */ static final class Pos extends Node { Node cond; Pos(Node cond) { this.cond = cond; } boolean match(Matcher matcher, int i, CharSequence seq) { int savedTo = matcher.to; boolean conditionMatched; // Relax transparent region boundaries for lookahead if (matcher.transparentBounds) matcher.to = matcher.getTextLength(); try { conditionMatched = cond.match(matcher, i, seq); } finally { // Reinstate region boundaries matcher.to = savedTo; } return conditionMatched && next.match(matcher, i, seq); } } /** * Zero width negative lookahead. */ static final class Neg extends Node { Node cond; Neg(Node cond) { this.cond = cond; } boolean match(Matcher matcher, int i, CharSequence seq) { int savedTo = matcher.to; boolean conditionMatched; // Relax transparent region boundaries for lookahead if (matcher.transparentBounds) matcher.to = matcher.getTextLength(); try { if (i < matcher.to) { conditionMatched = !cond.match(matcher, i, seq); } else { // If a negative lookahead succeeds then more input // could cause it to fail! matcher.requireEnd = true; conditionMatched = !cond.match(matcher, i, seq); } } finally { // Reinstate region boundaries matcher.to = savedTo; } return conditionMatched && next.match(matcher, i, seq); } } /** * For use with lookbehinds; matches the position where the lookbehind * was encountered. */ static class LookBehindEndNode extends Node { private LookBehindEndNode() { } // Singleton static LookBehindEndNode INSTANCE = new LookBehindEndNode(); boolean match(Matcher matcher, int i, CharSequence seq) { return i == matcher.lookbehindTo; } } /** * Zero width positive lookbehind. */ static class Behind extends Node { Node cond; int rmax, rmin; Behind(Node cond, int rmax, int rmin) { this.cond = cond; this.rmax = rmax; this.rmin = rmin; } boolean match(Matcher matcher, int i, CharSequence seq) { int savedFrom = matcher.from; boolean conditionMatched = false; int startIndex = (!matcher.transparentBounds) ? matcher.from : 0; int from = Math.max(i - rmax, startIndex); // Set end boundary int savedLBT = matcher.lookbehindTo; matcher.lookbehindTo = i; // Relax transparent region boundaries for lookbehind if (matcher.transparentBounds) matcher.from = 0; for (int j = i - rmin; !conditionMatched && j >= from; j--) { conditionMatched = cond.match(matcher, j, seq); } matcher.from = savedFrom; matcher.lookbehindTo = savedLBT; return conditionMatched && next.match(matcher, i, seq); } } /** * Zero width positive lookbehind, including supplementary * characters or unpaired surrogates. */ static final class BehindS extends Behind { BehindS(Node cond, int rmax, int rmin) { super(cond, rmax, rmin); } boolean match(Matcher matcher, int i, CharSequence seq) { int rmaxChars = countChars(seq, i, -rmax); int rminChars = countChars(seq, i, -rmin); int savedFrom = matcher.from; int startIndex = (!matcher.transparentBounds) ? matcher.from : 0; boolean conditionMatched = false; int from = Math.max(i - rmaxChars, startIndex); // Set end boundary int savedLBT = matcher.lookbehindTo; matcher.lookbehindTo = i; // Relax transparent region boundaries for lookbehind if (matcher.transparentBounds) matcher.from = 0; for (int j = i - rminChars; !conditionMatched && j >= from; j -= j > from ? countChars(seq, j, -1) : 1) { conditionMatched = cond.match(matcher, j, seq); } matcher.from = savedFrom; matcher.lookbehindTo = savedLBT; return conditionMatched && next.match(matcher, i, seq); } } /** * Zero width negative lookbehind. */ static class NotBehind extends Node { Node cond; int rmax, rmin; NotBehind(Node cond, int rmax, int rmin) { this.cond = cond; this.rmax = rmax; this.rmin = rmin; } boolean match(Matcher matcher, int i, CharSequence seq) { int savedLBT = matcher.lookbehindTo; int savedFrom = matcher.from; boolean conditionMatched = false; int startIndex = (!matcher.transparentBounds) ? matcher.from : 0; int from = Math.max(i - rmax, startIndex); matcher.lookbehindTo = i; // Relax transparent region boundaries for lookbehind if (matcher.transparentBounds) matcher.from = 0; for (int j = i - rmin; !conditionMatched && j >= from; j--) { conditionMatched = cond.match(matcher, j, seq); } // Reinstate region boundaries matcher.from = savedFrom; matcher.lookbehindTo = savedLBT; return !conditionMatched && next.match(matcher, i, seq); } } /** * Zero width negative lookbehind, including supplementary * characters or unpaired surrogates. */ static final class NotBehindS extends NotBehind { NotBehindS(Node cond, int rmax, int rmin) { super(cond, rmax, rmin); } boolean match(Matcher matcher, int i, CharSequence seq) { int rmaxChars = countChars(seq, i, -rmax); int rminChars = countChars(seq, i, -rmin); int savedFrom = matcher.from; int savedLBT = matcher.lookbehindTo; boolean conditionMatched = false; int startIndex = (!matcher.transparentBounds) ? matcher.from : 0; int from = Math.max(i - rmaxChars, startIndex); matcher.lookbehindTo = i; // Relax transparent region boundaries for lookbehind if (matcher.transparentBounds) matcher.from = 0; for (int j = i - rminChars; !conditionMatched && j >= from; j -= j > from ? countChars(seq, j, -1) : 1) { conditionMatched = cond.match(matcher, j, seq); } //Reinstate region boundaries matcher.from = savedFrom; matcher.lookbehindTo = savedLBT; return !conditionMatched && next.match(matcher, i, seq); } } /** * Handles word boundaries. Includes a field to allow this one class to * deal with the different types of word boundaries we can match. The word * characters include underscores, letters, and digits. Non spacing marks * can are also part of a word if they have a base character, otherwise * they are ignored for purposes of finding word boundaries. */ static final class Bound extends Node { static int LEFT = 0x1; static int RIGHT = 0x2; static int BOTH = 0x3; static int NONE = 0x4; int type; boolean useUWORD; Bound(int n, boolean useUWORD) { type = n; this.useUWORD = useUWORD; } boolean isWord(int ch) { return useUWORD ? CharPredicates.WORD().is(ch) : (ch == '_' || Character.isLetterOrDigit(ch)); } int check(Matcher matcher, int i, CharSequence seq) { int ch; boolean left = false; int startIndex = matcher.from; int endIndex = matcher.to; if (matcher.transparentBounds) { startIndex = 0; endIndex = matcher.getTextLength(); } if (i > startIndex) { ch = Character.codePointBefore(seq, i); left = (isWord(ch) || ((Character.getType(ch) == Character.NON_SPACING_MARK) && hasBaseCharacter(matcher, i - 1, seq))); } boolean right = false; if (i < endIndex) { ch = Character.codePointAt(seq, i); right = (isWord(ch) || ((Character.getType(ch) == Character.NON_SPACING_MARK) && hasBaseCharacter(matcher, i, seq))); } else { // Tried to access char past the end matcher.hitEnd = true; // The addition of another char could wreck a boundary matcher.requireEnd = true; } return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE); } boolean match(Matcher matcher, int i, CharSequence seq) { return (check(matcher, i, seq) & type) > 0 && next.match(matcher, i, seq); } } /** * Non spacing marks only count as word characters in bounds calculations * if they have a base character. */ private static boolean hasBaseCharacter(Matcher matcher, int i, CharSequence seq) { int start = (!matcher.transparentBounds) ? matcher.from : 0; for (int x = i; x >= start; x--) { int ch = Character.codePointAt(seq, x); if (Character.isLetterOrDigit(ch)) return true; if (Character.getType(ch) == Character.NON_SPACING_MARK) continue; return false; } return false; } /** * Attempts to match a slice in the input using the Boyer-Moore string * matching algorithm. The algorithm is based on the idea that the * pattern can be shifted farther ahead in the search text if it is * matched right to left. * <p> * The pattern is compared to the input one character at a time, from * the rightmost character in the pattern to the left. If the characters * all match the pattern has been found. If a character does not match, * the pattern is shifted right a distance that is the maximum of two * functions, the bad character shift and the good suffix shift. This * shift moves the attempted match position through the input more * quickly than a naive one position at a time check. * <p> * The bad character shift is based on the character from the text that * did not match. If the character does not appear in the pattern, the * pattern can be shifted completely beyond the bad character. If the * character does occur in the pattern, the pattern can be shifted to * line the pattern up with the next occurrence of that character. * <p> * The good suffix shift is based on the idea that some subset on the right * side of the pattern has matched. When a bad character is found, the * pattern can be shifted right by the pattern length if the subset does * not occur again in pattern, or by the amount of distance to the * next occurrence of the subset in the pattern. * * Boyer-Moore search methods adapted from code by Amy Yu. */ static class BnM extends Node { int[] buffer; int[] lastOcc; int[] optoSft; /** * Pre calculates arrays needed to generate the bad character * shift and the good suffix shift. Only the last seven bits * are used to see if chars match; This keeps the tables small * and covers the heavily used ASCII range, but occasionally * results in an aliased match for the bad character shift. */ static Node optimize(Node node) { if (!(node instanceof Slice)) { return node; } int[] src = ((Slice) node).buffer; int patternLength = src.length; // The BM algorithm requires a bit of overhead; // If the pattern is short don't use it, since // a shift larger than the pattern length cannot // be used anyway. if (patternLength < 4) { return node; } int i, j; int[] lastOcc = new int[128]; int[] optoSft = new int[patternLength]; // Precalculate part of the bad character shift // It is a table for where in the pattern each // lower 7-bit value occurs for (i = 0; i < patternLength; i++) { lastOcc[src[i] & 0x7F] = i + 1; } // Precalculate the good suffix shift // i is the shift amount being considered NEXT: for (i = patternLength; i > 0; i--) { // j is the beginning index of suffix being considered for (j = patternLength - 1; j >= i; j--) { // Testing for good suffix if (src[j] == src[j - i]) { // src[j..len] is a good suffix optoSft[j - 1] = i; } else { // No match. The array has already been // filled up with correct values before. continue NEXT; } } // This fills up the remaining of optoSft // any suffix can not have larger shift amount // then its sub-suffix. Why??? while (j > 0) { optoSft[--j] = i; } } // Set the guard value because of unicode compression optoSft[patternLength - 1] = 1; if (node instanceof SliceS) return new BnMS(src, lastOcc, optoSft, node.next); return new BnM(src, lastOcc, optoSft, node.next); } BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) { this.buffer = src; this.lastOcc = lastOcc; this.optoSft = optoSft; this.next = next; } boolean match(Matcher matcher, int i, CharSequence seq) { int[] src = buffer; int patternLength = src.length; int last = matcher.to - patternLength; // Loop over all possible match positions in text NEXT: while (i <= last) { // Loop over pattern from right to left for (int j = patternLength - 1; j >= 0; j--) { int ch = seq.charAt(i + j); if (ch != src[j]) { // Shift search to the right by the maximum of the // bad character shift and the good suffix shift i += Math.max(j + 1 - lastOcc[ch & 0x7F], optoSft[j]); continue NEXT; } } // Entire pattern matched starting at i matcher.first = i; boolean ret = next.match(matcher, i + patternLength, seq); if (ret) { matcher.first = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } i++; } // BnM is only used as the leading node in the unanchored case, // and it replaced its Start() which always searches to the end // if it doesn't find what it's looking for, so hitEnd is true. matcher.hitEnd = true; return false; } boolean study(TreeInfo info) { info.minLength += buffer.length; info.maxValid = false; return next.study(info); } } /** * Supplementary support version of BnM(). Unpaired surrogates are * also handled by this class. */ static final class BnMS extends BnM { int lengthInChars; BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) { super(src, lastOcc, optoSft, next); for (int cp : buffer) { lengthInChars += Character.charCount(cp); } } boolean match(Matcher matcher, int i, CharSequence seq) { int[] src = buffer; int patternLength = src.length; int last = matcher.to - lengthInChars; // Loop over all possible match positions in text NEXT: while (i <= last) { // Loop over pattern from right to left int ch; for (int j = countChars(seq, i, patternLength), x = patternLength - 1; j > 0; j -= Character .charCount(ch), x--) { ch = Character.codePointBefore(seq, i + j); if (ch != src[x]) { // Shift search to the right by the maximum of the // bad character shift and the good suffix shift int n = Math.max(x + 1 - lastOcc[ch & 0x7F], optoSft[x]); i += countChars(seq, i, n); continue NEXT; } } // Entire pattern matched starting at i matcher.first = i; boolean ret = next.match(matcher, i + lengthInChars, seq); if (ret) { matcher.first = i; matcher.groups[0] = matcher.first; matcher.groups[1] = matcher.last; return true; } i += countChars(seq, i, 1); } matcher.hitEnd = true; return false; } } @FunctionalInterface static interface CharPredicate { boolean is(int ch); default CharPredicate and(CharPredicate p) { return ch -> is(ch) && p.is(ch); } default CharPredicate union(CharPredicate p) { return ch -> is(ch) || p.is(ch); } default CharPredicate union(CharPredicate p1, CharPredicate p2) { return ch -> is(ch) || p1.is(ch) || p2.is(ch); } default CharPredicate negate() { return ch -> !is(ch); } } static interface BmpCharPredicate extends CharPredicate { default CharPredicate and(CharPredicate p) { if (p instanceof BmpCharPredicate) return (BmpCharPredicate) (ch -> is(ch) && p.is(ch)); return ch -> is(ch) && p.is(ch); } default CharPredicate union(CharPredicate p) { if (p instanceof BmpCharPredicate) return (BmpCharPredicate) (ch -> is(ch) || p.is(ch)); return ch -> is(ch) || p.is(ch); } static CharPredicate union(CharPredicate... predicates) { CharPredicate cp = ch -> { for (CharPredicate p : predicates) { if (!p.is(ch)) return false; } return true; }; for (CharPredicate p : predicates) { if (!(p instanceof BmpCharPredicate)) return cp; } return (BmpCharPredicate) cp; } } /** * matches a Perl vertical whitespace */ static BmpCharPredicate VertWS() { return cp -> (cp >= 0x0A && cp <= 0x0D) || cp == 0x85 || cp == 0x2028 || cp == 0x2029; } /** * matches a Perl horizontal whitespace */ static BmpCharPredicate HorizWS() { return cp -> cp == 0x09 || cp == 0x20 || cp == 0xa0 || cp == 0x1680 || cp == 0x180e || cp >= 0x2000 && cp <= 0x200a || cp == 0x202f || cp == 0x205f || cp == 0x3000; } /** * for the Unicode category ALL and the dot metacharacter when * in dotall mode. */ static CharPredicate ALL() { return ch -> true; } /** * for the dot metacharacter when dotall is not enabled. */ static CharPredicate DOT() { return ch -> (ch != '\n' && ch != '\r' && (ch | 1) != '\u2029' && ch != '\u0085'); } /** * the dot metacharacter when dotall is not enabled but UNIX_LINES is enabled. */ static CharPredicate UNIXDOT() { return ch -> ch != '\n'; } /** * Indicate that matches a Supplementary Unicode character */ static CharPredicate SingleS(int c) { return ch -> ch == c; } /** * A bmp/optimized predicate of single */ static BmpCharPredicate Single(int c) { return ch -> ch == c; } /** * Case insensitive matches a given BMP character */ static BmpCharPredicate SingleI(int lower, int upper) { return ch -> ch == lower || ch == upper; } /** * Unicode case insensitive matches a given Unicode character */ static CharPredicate SingleU(int lower) { return ch -> lower == ch || lower == Character.toLowerCase(Character.toUpperCase(ch)); } private static boolean inRange(int lower, int ch, int upper) { return lower <= ch && ch <= upper; } /** * Charactrs within a explicit value range */ static CharPredicate Range(int lower, int upper) { if (upper < Character.MIN_HIGH_SURROGATE || lower > Character.MAX_HIGH_SURROGATE && upper < Character.MIN_SUPPLEMENTARY_CODE_POINT) return (BmpCharPredicate) (ch -> inRange(lower, ch, upper)); return ch -> inRange(lower, ch, upper); } /** * Charactrs within a explicit value range in a case insensitive manner. */ static CharPredicate CIRange(int lower, int upper) { return ch -> inRange(lower, ch, upper) || ASCII.isAscii(ch) && (inRange(lower, ASCII.toUpper(ch), upper) || inRange(lower, ASCII.toLower(ch), upper)); } static CharPredicate CIRangeU(int lower, int upper) { return ch -> { if (inRange(lower, ch, upper)) return true; int up = Character.toUpperCase(ch); return inRange(lower, up, upper) || inRange(lower, Character.toLowerCase(up), upper); }; } /** * This must be the very first initializer. */ static final Node accept = new Node(); static final Node lastAccept = new LastNode(); /** * Creates a predicate that tests if this pattern is found in a given input * string. * * @apiNote * This method creates a predicate that behaves as if it creates a matcher * from the input sequence and then calls {@code find}, for example a * predicate of the form: * <pre>{@code * s -> matcher(s).find(); * }</pre> * * @return The predicate which can be used for finding a match on a * subsequence of a string * @since 1.8 * @see Matcher#find */ public Predicate<String> asPredicate() { return s -> matcher(s).find(); } /** * Creates a predicate that tests if this pattern matches a given input string. * * @apiNote * This method creates a predicate that behaves as if it creates a matcher * from the input sequence and then calls {@code matches}, for example a * predicate of the form: * <pre>{@code * s -> matcher(s).matches(); * }</pre> * * @return The predicate which can be used for matching an input string * against this pattern. * @since 11 * @see Matcher#matches */ public Predicate<String> asMatchPredicate() { return s -> matcher(s).matches(); } /** * Creates a stream from the given input sequence around matches of this * pattern. * * <p> The stream returned by this method contains each substring of the * input sequence that is terminated by another subsequence that matches * this pattern or is terminated by the end of the input sequence. The * substrings in the stream are in the order in which they occur in the * input. Trailing empty strings will be discarded and not encountered in * the stream. * * <p> If this pattern does not match any subsequence of the input then * the resulting stream has just one element, namely the input sequence in * string form. * * <p> When there is a positive-width match at the beginning of the input * sequence then an empty leading substring is included at the beginning * of the stream. A zero-width match at the beginning however never produces * such empty leading substring. * * <p> If the input sequence is mutable, it must remain constant during the * execution of the terminal stream operation. Otherwise, the result of the * terminal stream operation is undefined. * * @param input * The character sequence to be split * * @return The stream of strings computed by splitting the input * around matches of this pattern * @see #split(CharSequence) * @since 1.8 */ public Stream<String> splitAsStream(final CharSequence input) { class MatcherIterator implements Iterator<String> { private Matcher matcher; // The start position of the next sub-sequence of input // when current == input.length there are no more elements private int current; // null if the next element, if any, needs to obtained private String nextElement; // > 0 if there are N next empty elements private int emptyElementCount; public String next() { if (!hasNext()) throw new NoSuchElementException(); if (emptyElementCount == 0) { String n = nextElement; nextElement = null; return n; } else { emptyElementCount--; return ""; } } public boolean hasNext() { if (matcher == null) { matcher = matcher(input); // If the input is an empty string then the result can only be a // stream of the input. Induce that by setting the empty // element count to 1 emptyElementCount = input.length() == 0 ? 1 : 0; } if (nextElement != null || emptyElementCount > 0) return true; if (current == input.length()) return false; // Consume the next matching element // Count sequence of matching empty elements while (matcher.find()) { nextElement = input.subSequence(current, matcher.start()).toString(); current = matcher.end(); if (!nextElement.isEmpty()) { return true; } else if (current > 0) { // no empty leading substring for zero-width // match at the beginning of the input emptyElementCount++; } } // Consume last matching element nextElement = input.subSequence(current, input.length()).toString(); current = input.length(); if (!nextElement.isEmpty()) { return true; } else { // Ignore a terminal sequence of matching empty elements emptyElementCount = 0; nextElement = null; return false; } } } return StreamSupport.stream(Spliterators.spliteratorUnknownSize(new MatcherIterator(), Spliterator.ORDERED | Spliterator.NONNULL), false); } }