1 /*
2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util.regex;
27
28 import java.text.Normalizer;
29 import java.text.Normalizer.Form;
30 import java.util.Locale;
31 import java.util.Iterator;
32 import java.util.Map;
33 import java.util.ArrayList;
34 import java.util.HashMap;
35 import java.util.LinkedHashSet;
36 import java.util.List;
37 import java.util.Set;
38 import java.util.Arrays;
39 import java.util.NoSuchElementException;
40 import java.util.Spliterator;
41 import java.util.Spliterators;
42 import java.util.function.Predicate;
43 import java.util.stream.Stream;
44 import java.util.stream.StreamSupport;
45
46
47 /**
48 * A compiled representation of a regular expression.
49 *
50 * <p> A regular expression, specified as a string, must first be compiled into
51 * an instance of this class. The resulting pattern can then be used to create
52 * a {@link Matcher} object that can match arbitrary {@linkplain
53 * java.lang.CharSequence character sequences} against the regular
54 * expression. All of the state involved in performing a match resides in the
55 * matcher, so many matchers can share the same pattern.
56 *
57 * <p> A typical invocation sequence is thus
58 *
59 * <blockquote><pre>
60 * Pattern p = Pattern.{@link #compile compile}("a*b");
61 * Matcher m = p.{@link #matcher matcher}("aaaaab");
62 * boolean b = m.{@link Matcher#matches matches}();</pre></blockquote>
63 *
64 * <p> A {@link #matches matches} method is defined by this class as a
65 * convenience for when a regular expression is used just once. This method
66 * compiles an expression and matches an input sequence against it in a single
67 * invocation. The statement
68 *
69 * <blockquote><pre>
70 * boolean b = Pattern.matches("a*b", "aaaaab");</pre></blockquote>
71 *
72 * is equivalent to the three statements above, though for repeated matches it
73 * is less efficient since it does not allow the compiled pattern to be reused.
74 *
75 * <p> Instances of this class are immutable and are safe for use by multiple
76 * concurrent threads. Instances of the {@link Matcher} class are not safe for
77 * such use.
78 *
79 *
80 * <h3><a id="sum">Summary of regular-expression constructs</a></h3>
81 *
82 * <table class="borderless">
83 * <caption style="display:none">Regular expression constructs, and what they match</caption>
84 * <thead style="text-align:left">
85 * <tr>
86 * <th id="construct">Construct</th>
87 * <th id="matches">Matches</th>
88 * </tr>
89 * </thead>
90 * <tbody style="text-align:left">
91 *
92 * <tr><th colspan="2" style="padding-top:20px" id="characters">Characters</th></tr>
93 *
94 * <tr><th style="vertical-align:top; font-weight: normal" id="x"><i>x</i></th>
95 * <td headers="matches characters x">The character <i>x</i></td></tr>
96 * <tr><th style="vertical-align:top; font-weight: normal" id="backslash">{@code \\}</th>
97 * <td headers="matches characters backslash">The backslash character</td></tr>
98 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_n">{@code \0}<i>n</i></th>
99 * <td headers="matches characters octal_n">The character with octal value {@code 0}<i>n</i>
100 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
101 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nn">{@code \0}<i>nn</i></th>
102 * <td headers="matches characters octal_nn">The character with octal value {@code 0}<i>nn</i>
103 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
104 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nnn">{@code \0}<i>mnn</i></th>
105 * <td headers="matches characters octal_nnn">The character with octal value {@code 0}<i>mnn</i>
106 * (0 {@code <=} <i>m</i> {@code <=} 3,
107 * 0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
108 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hh">{@code \x}<i>hh</i></th>
109 * <td headers="matches characters hex_hh">The character with hexadecimal value {@code 0x}<i>hh</i></td></tr>
110 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hhhh"><code>\u</code><i>hhhh</i></th>
111 * <td headers="matches characters hex_hhhh">The character with hexadecimal value {@code 0x}<i>hhhh</i></td></tr>
112 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_h_h"><code>\x</code><i>{h...h}</i></th>
113 * <td headers="matches characters hex_h_h">The character with hexadecimal value {@code 0x}<i>h...h</i>
114 * ({@link java.lang.Character#MIN_CODE_POINT Character.MIN_CODE_POINT}
115 * <= {@code 0x}<i>h...h</i> <=
116 * {@link java.lang.Character#MAX_CODE_POINT Character.MAX_CODE_POINT})</td></tr>
117 * <tr><th style="vertical-align:top; font-weight: normal" id="unicode_name"><code>\N{</code><i>name</i><code>}</code></th>
118 * <td headers="matches characters unicode_name">The character with Unicode character name <i>'name'</i></td></tr>
119 * <tr><th style="vertical-align:top; font-weight:normal" id="tab">{@code \t}</th>
120 * <td headers="matches characters tab">The tab character (<code>'\u0009'</code>)</td></tr>
121 * <tr><th style="vertical-align:top; font-weight:normal" id="newline">{@code \n}</th>
122 * <td headers="matches characters newline">The newline (line feed) character (<code>'\u000A'</code>)</td></tr>
123 * <tr><th style="vertical-align:top; font-weight:normal" id="return">{@code \r}</th>
124 * <td headers="matches characters return">The carriage-return character (<code>'\u000D'</code>)</td></tr>
125 * <tr><th style="vertical-align:top; font-weight:normal" id="form_feed">{@code \f}</th>
126 * <td headers="matches characters form_feed">The form-feed character (<code>'\u000C'</code>)</td></tr>
127 * <tr><th style="vertical-align:top; font-weight:normal" id="bell">{@code \a}</th>
128 * <td headers="matches characters bell">The alert (bell) character (<code>'\u0007'</code>)</td></tr>
129 * <tr><th style="vertical-align:top; font-weight:normal" id="escape">{@code \e}</th>
130 * <td headers="matches characters escape">The escape character (<code>'\u001B'</code>)</td></tr>
131 * <tr><th style="vertical-align:top; font-weight:normal" id="ctrl_x">{@code \c}<i>x</i></th>
132 * <td headers="matches characters ctrl_x">The control character corresponding to <i>x</i></td></tr>
133 *
134 * <tr><th colspan="2" style="padding-top:20px" id="classes">Character classes</th></tr>
135 *
136 * <tr><th style="vertical-align:top; font-weight:normal" id="simple">{@code [abc]}</th>
137 * <td headers="matches classes simple">{@code a}, {@code b}, or {@code c} (simple class)</td></tr>
138 * <tr><th style="vertical-align:top; font-weight:normal" id="negation">{@code [^abc]}</th>
139 * <td headers="matches classes negation">Any character except {@code a}, {@code b}, or {@code c} (negation)</td></tr>
140 * <tr><th style="vertical-align:top; font-weight:normal" id="range">{@code [a-zA-Z]}</th>
141 * <td headers="matches classes range">{@code a} through {@code z}
142 * or {@code A} through {@code Z}, inclusive (range)</td></tr>
143 * <tr><th style="vertical-align:top; font-weight:normal" id="union">{@code [a-d[m-p]]}</th>
144 * <td headers="matches classes union">{@code a} through {@code d},
145 * or {@code m} through {@code p}: {@code [a-dm-p]} (union)</td></tr>
146 * <tr><th style="vertical-align:top; font-weight:normal" id="intersection">{@code [a-z&&[def]]}</th>
147 * <td headers="matches classes intersection">{@code d}, {@code e}, or {@code f} (intersection)</tr>
148 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction1">{@code [a-z&&[^bc]]}</th>
149 * <td headers="matches classes subtraction1">{@code a} through {@code z},
150 * except for {@code b} and {@code c}: {@code [ad-z]} (subtraction)</td></tr>
151 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction2">{@code [a-z&&[^m-p]]}</th>
152 * <td headers="matches classes subtraction2">{@code a} through {@code z},
153 * and not {@code m} through {@code p}: {@code [a-lq-z]}(subtraction)</td></tr>
154 *
155 * <tr><th colspan="2" style="padding-top:20px" id="predef">Predefined character classes</th></tr>
156 *
157 * <tr><th style="vertical-align:top; font-weight:normal" id="any">{@code .}</th>
158 * <td headers="matches predef any">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
159 * <tr><th style="vertical-align:top; font-weight:normal" id="digit">{@code \d}</th>
160 * <td headers="matches predef digit">A digit: {@code [0-9]}</td></tr>
161 * <tr><th style="vertical-align:top; font-weight:normal" id="non_digit">{@code \D}</th>
162 * <td headers="matches predef non_digit">A non-digit: {@code [^0-9]}</td></tr>
163 * <tr><th style="vertical-align:top; font-weight:normal" id="horiz_white">{@code \h}</th>
164 * <td headers="matches predef horiz_white">A horizontal whitespace character:
165 * <code>[ \t\xA0\u1680\u180e\u2000-\u200a\u202f\u205f\u3000]</code></td></tr>
166 * <tr><th style="vertical-align:top; font-weight:normal" id="non_horiz_white">{@code \H}</th>
167 * <td headers="matches predef non_horiz_white">A non-horizontal whitespace character: {@code [^\h]}</td></tr>
168 * <tr><th style="vertical-align:top; font-weight:normal" id="white">{@code \s}</th>
169 * <td headers="matches predef white">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
170 * <tr><th style="vertical-align:top; font-weight:normal" id="non_white">{@code \S}</th>
171 * <td headers="matches predef non_white">A non-whitespace character: {@code [^\s]}</td></tr>
172 * <tr><th style="vertical-align:top; font-weight:normal" id="vert_white">{@code \v}</th>
173 * <td headers="matches predef vert_white">A vertical whitespace character: <code>[\n\x0B\f\r\x85\u2028\u2029]</code>
174 * </td></tr>
175 * <tr><th style="vertical-align:top; font-weight:normal" id="non_vert_white">{@code \V}</th>
176 * <td headers="matches predef non_vert_white">A non-vertical whitespace character: {@code [^\v]}</td></tr>
177 * <tr><th style="vertical-align:top; font-weight:normal" id="word">{@code \w}</th>
178 * <td headers="matches predef word">A word character: {@code [a-zA-Z_0-9]}</td></tr>
179 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word">{@code \W}</th>
180 * <td headers="matches predef non_word">A non-word character: {@code [^\w]}</td></tr>
181 *
182 * <tr><th colspan="2" style="padding-top:20px" id="posix"><b>POSIX character classes (US-ASCII only)</b></th></tr>
183 *
184 * <tr><th style="vertical-align:top; font-weight:normal" id="Lower">{@code \p{Lower}}</th>
185 * <td headers="matches posix Lower">A lower-case alphabetic character: {@code [a-z]}</td></tr>
186 * <tr><th style="vertical-align:top; font-weight:normal" id="Upper">{@code \p{Upper}}</th>
187 * <td headers="matches posix Upper">An upper-case alphabetic character:{@code [A-Z]}</td></tr>
188 * <tr><th style="vertical-align:top; font-weight:normal" id="ASCII">{@code \p{ASCII}}</th>
189 * <td headers="matches posix ASCII">All ASCII:{@code [\x00-\x7F]}</td></tr>
190 * <tr><th style="vertical-align:top; font-weight:normal" id="Alpha">{@code \p{Alpha}}</th>
191 * <td headers="matches posix Alpha">An alphabetic character:{@code [\p{Lower}\p{Upper}]}</td></tr>
192 * <tr><th style="vertical-align:top; font-weight:normal" id="Digit">{@code \p{Digit}}</th>
193 * <td headers="matches posix Digit">A decimal digit: {@code [0-9]}</td></tr>
194 * <tr><th style="vertical-align:top; font-weight:normal" id="Alnum">{@code \p{Alnum}}</th>
195 * <td headers="matches posix Alnum">An alphanumeric character:{@code [\p{Alpha}\p{Digit}]}</td></tr>
196 * <tr><th style="vertical-align:top; font-weight:normal" id="Punct">{@code \p{Punct}}</th>
197 * <td headers="matches posix Punct">Punctuation: One of {@code !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~}</td></tr>
198 * <!-- {@code [\!"#\$%&'\(\)\*\+,\-\./:;\<=\>\?@\[\\\]\^_`\{\|\}~]}
199 * {@code [\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]} -->
200 * <tr><th style="vertical-align:top; font-weight:normal" id="Graph">{@code \p{Graph}}</th>
201 * <td headers="matches posix Graph">A visible character: {@code [\p{Alnum}\p{Punct}]}</td></tr>
202 * <tr><th style="vertical-align:top; font-weight:normal" id="Print">{@code \p{Print}}</th>
203 * <td headers="matches posix Print">A printable character: {@code [\p{Graph}\x20]}</td></tr>
204 * <tr><th style="vertical-align:top; font-weight:normal" id="Blank">{@code \p{Blank}}</th>
205 * <td headers="matches posix Blank">A space or a tab: {@code [ \t]}</td></tr>
206 * <tr><th style="vertical-align:top; font-weight:normal" id="Cntrl">{@code \p{Cntrl}}</th>
207 * <td headers="matches posix Cntrl">A control character: {@code [\x00-\x1F\x7F]}</td></tr>
208 * <tr><th style="vertical-align:top; font-weight:normal" id="XDigit">{@code \p{XDigit}}</th>
209 * <td headers="matches posix XDigit">A hexadecimal digit: {@code [0-9a-fA-F]}</td></tr>
210 * <tr><th style="vertical-align:top; font-weight:normal" id="Space">{@code \p{Space}}</th>
211 * <td headers="matches posix Space">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
212 *
213 * <tr><th colspan="2" style="padding-top:20px" id="java">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr>
214 *
215 * <tr><th style="vertical-align:top; font-weight:normal" id="javaLowerCase">{@code \p{javaLowerCase}}</th>
216 * <td headers="matches java javaLowerCase">Equivalent to java.lang.Character.isLowerCase()</td></tr>
217 * <tr><th style="vertical-align:top; font-weight:normal" id="javaUpperCase">{@code \p{javaUpperCase}}</th>
218 * <td headers="matches java javaUpperCase">Equivalent to java.lang.Character.isUpperCase()</td></tr>
219 * <tr><th style="vertical-align:top; font-weight:normal" id="javaWhitespace">{@code \p{javaWhitespace}}</th>
220 * <td headers="matches java javaWhitespace">Equivalent to java.lang.Character.isWhitespace()</td></tr>
221 * <tr><th style="vertical-align:top; font-weight:normal" id="javaMirrored">{@code \p{javaMirrored}}</th>
222 * <td headers="matches java javaMirrored">Equivalent to java.lang.Character.isMirrored()</td></tr>
223 *
224 * <tr><th colspan="2" style="padding-top:20px" id="unicode">Classes for Unicode scripts, blocks, categories and binary properties</th></tr>
225 *
226 * <tr><th style="vertical-align:top; font-weight:normal" id="IsLatin">{@code \p{IsLatin}}</th>
227 * <td headers="matches unicode IsLatin">A Latin script character (<a href="#usc">script</a>)</td></tr>
228 * <tr><th style="vertical-align:top; font-weight:normal" id="InGreek">{@code \p{InGreek}}</th>
229 * <td headers="matches unicode InGreek">A character in the Greek block (<a href="#ubc">block</a>)</td></tr>
230 * <tr><th style="vertical-align:top; font-weight:normal" id="Lu">{@code \p{Lu}}</th>
231 * <td headers="matches unicode Lu">An uppercase letter (<a href="#ucc">category</a>)</td></tr>
232 * <tr><th style="vertical-align:top; font-weight:normal" id="IsAlphabetic">{@code \p{IsAlphabetic}}</th>
233 * <td headers="matches unicode IsAlphabetic">An alphabetic character (<a href="#ubpc">binary property</a>)</td></tr>
234 * <tr><th style="vertical-align:top; font-weight:normal" id="Sc">{@code \p{Sc}}</th>
235 * <td headers="matches unicode Sc">A currency symbol</td></tr>
236 * <tr><th style="vertical-align:top; font-weight:normal" id="not_InGreek">{@code \P{InGreek}}</th>
237 * <td headers="matches unicode not_InGreek">Any character except one in the Greek block (negation)</td></tr>
238 * <tr><th style="vertical-align:top; font-weight:normal" id="not_uppercase">{@code [\p{L}&&[^\p{Lu}]]}</th>
239 * <td headers="matches unicode not_uppercase">Any letter except an uppercase letter (subtraction)</td></tr>
240 *
241 * <tr><th colspan="2" style="padding-top:20px" id="bounds">Boundary matchers</th></tr>
242 *
243 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_line">{@code ^}</th>
244 * <td headers="matches bounds begin_line">The beginning of a line</td></tr>
245 * <tr><th style="vertical-align:top; font-weight:normal" id="end_line">{@code $}</th>
246 * <td headers="matches bounds end_line">The end of a line</td></tr>
247 * <tr><th style="vertical-align:top; font-weight:normal" id="word_boundary">{@code \b}</th>
248 * <td headers="matches bounds word_boundary">A word boundary</td></tr>
249 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_cluster_boundary">{@code \b{g}}</th>
250 * <td headers="matches bounds grapheme_cluster_boundary">A Unicode extended grapheme cluster boundary</td></tr>
251 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word_boundary">{@code \B}</th>
252 * <td headers="matches bounds non_word_boundary">A non-word boundary</td></tr>
253 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_input">{@code \A}</th>
254 * <td headers="matches bounds begin_input">The beginning of the input</td></tr>
255 * <tr><th style="vertical-align:top; font-weight:normal" id="end_prev_match">{@code \G}</th>
256 * <td headers="matches bounds end_prev_match">The end of the previous match</td></tr>
257 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input_except_term">{@code \Z}</th>
258 * <td headers="matches bounds end_input_except_term">The end of the input but for the final
259 * <a href="#lt">terminator</a>, if any</td></tr>
260 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input">{@code \z}</th>
261 * <td headers="matches bounds end_input">The end of the input</td></tr>
262 *
263 * <tr><th colspan="2" style="padding-top:20px" id="linebreak">Linebreak matcher</th></tr>
264 *
265 * <tr><th style="vertical-align:top; font-weight:normal" id="any_unicode_linebreak">{@code \R}</th>
266 * <td headers="matches linebreak any_unicode_linebreak">Any Unicode linebreak sequence, is equivalent to
267 * <code>\u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029]
268 * </code></td></tr>
269 *
270 * <tr><th colspan="2" style="padding-top:20px" id="grapheme">Unicode Extended Grapheme matcher</th></tr>
271 *
272 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_any">{@code \X}</th>
273 * <td headers="matches grapheme grapheme_any">Any Unicode extended grapheme cluster</td></tr>
274 *
275 * <tr><th colspan="2" style="padding-top:20px" id="greedy">Greedy quantifiers</th></tr>
276 *
277 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_once_or_not"><i>X</i>{@code ?}</th>
278 * <td headers="matches greedy greedy_once_or_not"><i>X</i>, once or not at all</td></tr>
279 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_zero_or_more"><i>X</i>{@code *}</th>
280 * <td headers="matches greedy greedy_zero_or_more"><i>X</i>, zero or more times</td></tr>
281 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_one_or_more"><i>X</i>{@code +}</th>
282 * <td headers="matches greedy greedy_one_or_more"><i>X</i>, one or more times</td></tr>
283 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_exactly"><i>X</i><code>{</code><i>n</i><code>}</code></th>
284 * <td headers="matches greedy greedy_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
285 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least"><i>X</i><code>{</code><i>n</i>{@code ,}}</th>
286 * <td headers="matches greedy greedy_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
287 * <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>
288 * <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>
289 *
290 * <tr><th colspan="2" style="padding-top:20px" id="reluc">Reluctant quantifiers</th></tr>
291 *
292 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_once_or_not"><i>X</i>{@code ??}</th>
293 * <td headers="matches reluc reluc_once_or_not"><i>X</i>, once or not at all</td></tr>
294 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_zero_or_more"><i>X</i>{@code *?}</th>
295 * <td headers="matches reluc reluc_zero_or_more"><i>X</i>, zero or more times</td></tr>
296 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_one_or_more"><i>X</i>{@code +?}</th>
297 * <td headers="matches reluc reluc_one_or_more"><i>X</i>, one or more times</td></tr>
298 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_exactly"><i>X</i><code>{</code><i>n</i><code>}?</code></th>
299 * <td headers="matches reluc reluc_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
300 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least"><i>X</i><code>{</code><i>n</i><code>,}?</code></th>
301 * <td headers="matches reluc reluc_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
302 * <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>
303 * <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>
304 *
305 * <tr><th colspan="2" style="padding-top:20px" id="poss">Possessive quantifiers</th></tr>
306 *
307 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_once_or_not"><i>X</i>{@code ?+}</th>
308 * <td headers="matches poss poss_once_or_not"><i>X</i>, once or not at all</td></tr>
309 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_zero_or_more"><i>X</i>{@code *+}</th>
310 * <td headers="matches poss poss_zero_or_more"><i>X</i>, zero or more times</td></tr>
311 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_one_or_more"><i>X</i>{@code ++}</th>
312 * <td headers="matches poss poss_one_or_more"><i>X</i>, one or more times</td></tr>
313 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_exactly"><i>X</i><code>{</code><i>n</i><code>}+</code></th>
314 * <td headers="matches poss poss_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
315 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least"><i>X</i><code>{</code><i>n</i><code>,}+</code></th>
316 * <td headers="matches poss poss_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
317 * <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>
318 * <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>
319 *
320 * <tr><th colspan="2" style="padding-top:20px" id="logical">Logical operators</th></tr>
321 *
322 * <tr><th style="vertical-align:top; font-weight:normal" id="concat"><i>XY</i></th>
323 * <td headers="matches logical concat"><i>X</i> followed by <i>Y</i></td></tr>
324 * <tr><th style="vertical-align:top; font-weight:normal" id="alternate"><i>X</i>{@code |}<i>Y</i></th>
325 * <td headers="matches logical alternate">Either <i>X</i> or <i>Y</i></td></tr>
326 * <tr><th style="vertical-align:top; font-weight:normal" id="group">{@code (}<i>X</i>{@code )}</th>
327 * <td headers="matches logical group">X, as a <a href="#cg">capturing group</a></td></tr>
328 *
329 * <tr><th colspan="2" style="padding-top:20px" id="backref">Back references</th></tr>
330 *
331 * <tr><th style="vertical-align:top; font-weight:normal" id="back_nth">{@code \}<i>n</i></th>
332 * <td headers="matches backref back_nth">Whatever the <i>n</i><sup>th</sup>
333 * <a href="#cg">capturing group</a> matched</td></tr>
334 * <tr><th style="vertical-align:top; font-weight:normal" id="back_named">{@code \}<i>k</i><<i>name</i>></th>
335 * <td headers="matches backref back_named">Whatever the
336 * <a href="#groupname">named-capturing group</a> "name" matched</td></tr>
337 *
338 * <tr><th colspan="2" style="padding-top:20px" id="quote">Quotation</th></tr>
339 *
340 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_follow">{@code \}</th>
341 * <td headers="matches quote quote_follow">Nothing, but quotes the following character</td></tr>
342 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_begin">{@code \Q}</th>
343 * <td headers="matches quote quote_begin">Nothing, but quotes all characters until {@code \E}</td></tr>
344 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_end">{@code \E}</th>
345 * <td headers="matches quote quote_end">Nothing, but ends quoting started by {@code \Q}</td></tr>
346 * <!-- Metachars: !$()*+.<>?[\]^{|} -->
347 *
348 * <tr><th colspan="2" style="padding-top:20px" id="special">Special constructs (named-capturing and non-capturing)</th></tr>
349 *
350 * <tr><th style="vertical-align:top; font-weight:normal" id="named_group"><code>(?<<a href="#groupname">name</a>></code><i>X</i>{@code )}</th>
351 * <td headers="matches special named_group"><i>X</i>, as a named-capturing group</td></tr>
352 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group">{@code (?:}<i>X</i>{@code )}</th>
353 * <td headers="matches special non_capture_group"><i>X</i>, as a non-capturing group</td></tr>
354 * <tr><th style="vertical-align:top; font-weight:normal" id="flags"><code>(?idmsuxU-idmsuxU) </code></th>
355 * <td headers="matches special flags">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a>
356 * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a>
357 * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> <a href="#UNICODE_CHARACTER_CLASS">U</a>
358 * on - off</td></tr>
359 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group_flags"><code>(?idmsux-idmsux:</code><i>X</i>{@code )} </th>
360 * <td headers="matches special non_capture_group_flags"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the
361 * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a>
362 * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a >
363 * <a href="#COMMENTS">x</a> on - off</td></tr>
364 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookahead">{@code (?=}<i>X</i>{@code )}</th>
365 * <td headers="matches special pos_lookahead"><i>X</i>, via zero-width positive lookahead</td></tr>
366 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookahead">{@code (?!}<i>X</i>{@code )}</th>
367 * <td headers="matches special neg_lookahead"><i>X</i>, via zero-width negative lookahead</td></tr>
368 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookbehind">{@code (?<=}<i>X</i>{@code )}</th>
369 * <td headers="matches special pos_lookbehind"><i>X</i>, via zero-width positive lookbehind</td></tr>
370 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookbehind">{@code (?<!}<i>X</i>{@code )}</th>
371 * <td headers="matches special neg_lookbehind"><i>X</i>, via zero-width negative lookbehind</td></tr>
372 * <tr><th style="vertical-align:top; font-weight:normal" id="indep_non_capture_group">{@code (?>}<i>X</i>{@code )}</th>
373 * <td headers="matches special indep_non_capture_group"><i>X</i>, as an independent, non-capturing group</td></tr>
374 *
375 * </tbody>
376 * </table>
377 *
378 * <hr>
379 *
380 *
381 * <h3><a id="bs">Backslashes, escapes, and quoting</a></h3>
382 *
383 * <p> The backslash character ({@code '\'}) serves to introduce escaped
384 * constructs, as defined in the table above, as well as to quote characters
385 * that otherwise would be interpreted as unescaped constructs. Thus the
386 * expression {@code \\} matches a single backslash and <code>\{</code> matches a
387 * left brace.
388 *
389 * <p> It is an error to use a backslash prior to any alphabetic character that
390 * does not denote an escaped construct; these are reserved for future
391 * extensions to the regular-expression language. A backslash may be used
392 * prior to a non-alphabetic character regardless of whether that character is
393 * part of an unescaped construct.
394 *
395 * <p> Backslashes within string literals in Java source code are interpreted
396 * as required by
397 * <cite>The Java™ Language Specification</cite>
398 * as either Unicode escapes (section 3.3) or other character escapes (section 3.10.6)
399 * It is therefore necessary to double backslashes in string
400 * literals that represent regular expressions to protect them from
401 * interpretation by the Java bytecode compiler. The string literal
402 * <code>"\b"</code>, for example, matches a single backspace character when
403 * interpreted as a regular expression, while {@code "\\b"} matches a
404 * word boundary. The string literal {@code "\(hello\)"} is illegal
405 * and leads to a compile-time error; in order to match the string
406 * {@code (hello)} the string literal {@code "\\(hello\\)"}
407 * must be used.
408 *
409 * <h3><a id="cc">Character Classes</a></h3>
410 *
411 * <p> Character classes may appear within other character classes, and
412 * may be composed by the union operator (implicit) and the intersection
413 * operator ({@code &&}).
414 * The union operator denotes a class that contains every character that is
415 * in at least one of its operand classes. The intersection operator
416 * denotes a class that contains every character that is in both of its
417 * operand classes.
418 *
419 * <p> The precedence of character-class operators is as follows, from
420 * highest to lowest:
421 *
422 * <table class="striped" style="margin-left: 2em;">
423 * <caption style="display:none">Precedence of character class operators.</caption>
424 * <thead>
425 * <tr><th scope="col">Precedence<th scope="col">Name<th scope="col">Example
426 * </thead>
427 * <tbody>
428 * <tr><th scope="row">1</th>
429 * <td>Literal escape </td>
430 * <td>{@code \x}</td></tr>
431 * <tr><th scope="row">2</th>
432 * <td>Grouping</td>
433 * <td>{@code [...]}</td></tr>
434 * <tr><th scope="row">3</th>
435 * <td>Range</td>
436 * <td>{@code a-z}</td></tr>
437 * <tr><th scope="row">4</th>
438 * <td>Union</td>
439 * <td>{@code [a-e][i-u]}</td></tr>
440 * <tr><th scope="row">5</th>
441 * <td>Intersection</td>
442 * <td>{@code [a-z&&[aeiou]]}</td></tr>
443 * </tbody>
444 * </table>
445 *
446 * <p> Note that a different set of metacharacters are in effect inside
447 * a character class than outside a character class. For instance, the
448 * regular expression {@code .} loses its special meaning inside a
449 * character class, while the expression {@code -} becomes a range
450 * forming metacharacter.
451 *
452 * <h3><a id="lt">Line terminators</a></h3>
453 *
454 * <p> A <i>line terminator</i> is a one- or two-character sequence that marks
455 * the end of a line of the input character sequence. The following are
456 * recognized as line terminators:
457 *
458 * <ul>
459 *
460 * <li> A newline (line feed) character ({@code '\n'}),
461 *
462 * <li> A carriage-return character followed immediately by a newline
463 * character ({@code "\r\n"}),
464 *
465 * <li> A standalone carriage-return character ({@code '\r'}),
466 *
467 * <li> A next-line character (<code>'\u0085'</code>),
468 *
469 * <li> A line-separator character (<code>'\u2028'</code>), or
470 *
471 * <li> A paragraph-separator character (<code>'\u2029'</code>).
472 *
473 * </ul>
474 * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators
475 * recognized are newline characters.
476 *
477 * <p> The regular expression {@code .} matches any character except a line
478 * terminator unless the {@link #DOTALL} flag is specified.
479 *
480 * <p> By default, the regular expressions {@code ^} and {@code $} ignore
481 * line terminators and only match at the beginning and the end, respectively,
482 * of the entire input sequence. If {@link #MULTILINE} mode is activated then
483 * {@code ^} matches at the beginning of input and after any line terminator
484 * except at the end of input. When in {@link #MULTILINE} mode {@code $}
485 * matches just before a line terminator or the end of the input sequence.
486 *
487 * <h3><a id="cg">Groups and capturing</a></h3>
488 *
489 * <h4><a id="gnumber">Group number</a></h4>
490 * <p> Capturing groups are numbered by counting their opening parentheses from
491 * left to right. In the expression {@code ((A)(B(C)))}, for example, there
492 * are four such groups: </p>
493 *
494 * <ol style="margin-left:2em;">
495 * <li> {@code ((A)(B(C)))}
496 * <li> {@code (A)}
497 * <li> {@code (B(C))}
498 * <li> {@code (C)}
499 * </ol>
500 *
501 * <p> Group zero always stands for the entire expression.
502 *
503 * <p> Capturing groups are so named because, during a match, each subsequence
504 * of the input sequence that matches such a group is saved. The captured
505 * subsequence may be used later in the expression, via a back reference, and
506 * may also be retrieved from the matcher once the match operation is complete.
507 *
508 * <h4><a id="groupname">Group name</a></h4>
509 * <p>A capturing group can also be assigned a "name", a {@code named-capturing group},
510 * and then be back-referenced later by the "name". Group names are composed of
511 * the following characters. The first character must be a {@code letter}.
512 *
513 * <ul>
514 * <li> The uppercase letters {@code 'A'} through {@code 'Z'}
515 * (<code>'\u0041'</code> through <code>'\u005a'</code>),
516 * <li> The lowercase letters {@code 'a'} through {@code 'z'}
517 * (<code>'\u0061'</code> through <code>'\u007a'</code>),
518 * <li> The digits {@code '0'} through {@code '9'}
519 * (<code>'\u0030'</code> through <code>'\u0039'</code>),
520 * </ul>
521 *
522 * <p> A {@code named-capturing group} is still numbered as described in
523 * <a href="#gnumber">Group number</a>.
524 *
525 * <p> The captured input associated with a group is always the subsequence
526 * that the group most recently matched. If a group is evaluated a second time
527 * because of quantification then its previously-captured value, if any, will
528 * be retained if the second evaluation fails. Matching the string
529 * {@code "aba"} against the expression {@code (a(b)?)+}, for example, leaves
530 * group two set to {@code "b"}. All captured input is discarded at the
531 * beginning of each match.
532 *
533 * <p> Groups beginning with {@code (?} are either pure, <i>non-capturing</i> groups
534 * that do not capture text and do not count towards the group total, or
535 * <i>named-capturing</i> group.
536 *
537 * <h3> Unicode support </h3>
538 *
539 * <p> This class is in conformance with Level 1 of <a
540 * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
541 * Standard #18: Unicode Regular Expression</i></a>, plus RL2.1
542 * Canonical Equivalents.
543 * <p>
544 * <b>Unicode escape sequences</b> such as <code>\u2014</code> in Java source code
545 * are processed as described in section 3.3 of
546 * <cite>The Java™ Language Specification</cite>.
547 * Such escape sequences are also implemented directly by the regular-expression
548 * parser so that Unicode escapes can be used in expressions that are read from
549 * files or from the keyboard. Thus the strings <code>"\u2014"</code> and
550 * {@code "\\u2014"}, while not equal, compile into the same pattern, which
551 * matches the character with hexadecimal value {@code 0x2014}.
552 * <p>
553 * A Unicode character can also be represented by using its <b>Hex notation</b>
554 * (hexadecimal code point value) directly as described in construct
555 * <code>\x{...}</code>, for example a supplementary character U+2011F can be
556 * specified as <code>\x{2011F}</code>, instead of two consecutive Unicode escape
557 * sequences of the surrogate pair <code>\uD840</code><code>\uDD1F</code>.
558 * <p>
559 * <b>Unicode character names</b> are supported by the named character construct
560 * <code>\N{</code>...<code>}</code>, for example, <code>\N{WHITE SMILING FACE}</code>
561 * specifies character <code>\u263A</code>. The character names supported
562 * by this class are the valid Unicode character names matched by
563 * {@link java.lang.Character#codePointOf(String) Character.codePointOf(name)}.
564 * <p>
565 * <a href="http://www.unicode.org/reports/tr18/#Default_Grapheme_Clusters">
566 * <b>Unicode extended grapheme clusters</b></a> are supported by the grapheme
567 * cluster matcher {@code \X} and the corresponding boundary matcher {@code \b{g}}.
568 * <p>
569 * Unicode scripts, blocks, categories and binary properties are written with
570 * the {@code \p} and {@code \P} constructs as in Perl.
571 * <code>\p{</code><i>prop</i><code>}</code> matches if
572 * the input has the property <i>prop</i>, while <code>\P{</code><i>prop</i><code>}</code>
573 * does not match if the input has that property.
574 * <p>
575 * Scripts, blocks, categories and binary properties can be used both inside
576 * and outside of a character class.
577 *
578 * <p>
579 * <b><a id="usc">Scripts</a></b> are specified either with the prefix {@code Is}, as in
580 * {@code IsHiragana}, or by using the {@code script} keyword (or its short
581 * form {@code sc}) as in {@code script=Hiragana} or {@code sc=Hiragana}.
582 * <p>
583 * The script names supported by {@code Pattern} are the valid script names
584 * accepted and defined by
585 * {@link java.lang.Character.UnicodeScript#forName(String) UnicodeScript.forName}.
586 *
587 * <p>
588 * <b><a id="ubc">Blocks</a></b> are specified with the prefix {@code In}, as in
589 * {@code InMongolian}, or by using the keyword {@code block} (or its short
590 * form {@code blk}) as in {@code block=Mongolian} or {@code blk=Mongolian}.
591 * <p>
592 * The block names supported by {@code Pattern} are the valid block names
593 * accepted and defined by
594 * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}.
595 * <p>
596 *
597 * <b><a id="ucc">Categories</a></b> may be specified with the optional prefix {@code Is}:
598 * Both {@code \p{L}} and {@code \p{IsL}} denote the category of Unicode
599 * letters. Same as scripts and blocks, categories can also be specified
600 * by using the keyword {@code general_category} (or its short form
601 * {@code gc}) as in {@code general_category=Lu} or {@code gc=Lu}.
602 * <p>
603 * The supported categories are those of
604 * <a href="http://www.unicode.org/unicode/standard/standard.html">
605 * <i>The Unicode Standard</i></a> in the version specified by the
606 * {@link java.lang.Character Character} class. The category names are those
607 * defined in the Standard, both normative and informative.
608 * <p>
609 *
610 * <b><a id="ubpc">Binary properties</a></b> are specified with the prefix {@code Is}, as in
611 * {@code IsAlphabetic}. The supported binary properties by {@code Pattern}
612 * are
613 * <ul>
614 * <li> Alphabetic
615 * <li> Ideographic
616 * <li> Letter
617 * <li> Lowercase
618 * <li> Uppercase
619 * <li> Titlecase
620 * <li> Punctuation
621 * <Li> Control
622 * <li> White_Space
623 * <li> Digit
624 * <li> Hex_Digit
625 * <li> Join_Control
626 * <li> Noncharacter_Code_Point
627 * <li> Assigned
628 * </ul>
629 * <p>
630 * The following <b>Predefined Character classes</b> and <b>POSIX character classes</b>
631 * are in conformance with the recommendation of <i>Annex C: Compatibility Properties</i>
632 * of <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Regular Expression
633 * </i></a>, when {@link #UNICODE_CHARACTER_CLASS} flag is specified.
634 *
635 * <table class="striped">
636 * <caption style="display:none">predefined and posix character classes in Unicode mode</caption>
637 * <thead>
638 * <tr>
639 * <th scope="col" id="predef_classes">Classes</th>
640 * <th scope="col" id="predef_matches">Matches</th>
641 * </tr>
642 * </thead>
643 * <tbody>
644 * <tr><th scope="row">{@code \p{Lower}}</th>
645 * <td>A lowercase character:{@code \p{IsLowercase}}</td></tr>
646 * <tr><th scope="row">{@code \p{Upper}}</th>
647 * <td>An uppercase character:{@code \p{IsUppercase}}</td></tr>
648 * <tr><th scope="row">{@code \p{ASCII}}</th>
649 * <td>All ASCII:{@code [\x00-\x7F]}</td></tr>
650 * <tr><th scope="row">{@code \p{Alpha}}</th>
651 * <td>An alphabetic character:{@code \p{IsAlphabetic}}</td></tr>
652 * <tr><th scope="row">{@code \p{Digit}}</th>
653 * <td>A decimal digit character:{@code \p{IsDigit}}</td></tr>
654 * <tr><th scope="row">{@code \p{Alnum}}</th>
655 * <td>An alphanumeric character:{@code [\p{IsAlphabetic}\p{IsDigit}]}</td></tr>
656 * <tr><th scope="row">{@code \p{Punct}}</th>
657 * <td>A punctuation character:{@code \p{IsPunctuation}}</td></tr>
658 * <tr><th scope="row">{@code \p{Graph}}</th>
659 * <td>A visible character: {@code [^\p{IsWhite_Space}\p{gc=Cc}\p{gc=Cs}\p{gc=Cn}]}</td></tr>
660 * <tr><th scope="row">{@code \p{Print}}</th>
661 * <td>A printable character: {@code [\p{Graph}\p{Blank}&&[^\p{Cntrl}]]}</td></tr>
662 * <tr><th scope="row">{@code \p{Blank}}</th>
663 * <td>A space or a tab: {@code [\p{IsWhite_Space}&&[^\p{gc=Zl}\p{gc=Zp}\x0a\x0b\x0c\x0d\x85]]}</td></tr>
664 * <tr><th scope="row">{@code \p{Cntrl}}</th>
665 * <td>A control character: {@code \p{gc=Cc}}</td></tr>
666 * <tr><th scope="row">{@code \p{XDigit}}</th>
667 * <td>A hexadecimal digit: {@code [\p{gc=Nd}\p{IsHex_Digit}]}</td></tr>
668 * <tr><th scope="row">{@code \p{Space}}</th>
669 * <td>A whitespace character:{@code \p{IsWhite_Space}}</td></tr>
670 * <tr><th scope="row">{@code \d}</th>
671 * <td>A digit: {@code \p{IsDigit}}</td></tr>
672 * <tr><th scope="row">{@code \D}</th>
673 * <td>A non-digit: {@code [^\d]}</td></tr>
674 * <tr><th scope="row">{@code \s}</th>
675 * <td>A whitespace character: {@code \p{IsWhite_Space}}</td></tr>
676 * <tr><th scope="row">{@code \S}</th>
677 * <td>A non-whitespace character: {@code [^\s]}</td></tr>
678 * <tr><th scope="row">{@code \w}</th>
679 * <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>
680 * <tr><th scope="row">{@code \W}</th>
681 * <td>A non-word character: {@code [^\w]}</td></tr>
682 * </tbody>
683 * </table>
684 * <p>
685 * <a id="jcc">
686 * Categories that behave like the java.lang.Character
687 * boolean is<i>methodname</i> methods (except for the deprecated ones) are
688 * available through the same <code>\p{</code><i>prop</i><code>}</code> syntax where
689 * the specified property has the name <code>java<i>methodname</i></code></a>.
690 *
691 * <h3> Comparison to Perl 5 </h3>
692 *
693 * <p>The {@code Pattern} engine performs traditional NFA-based matching
694 * with ordered alternation as occurs in Perl 5.
695 *
696 * <p> Perl constructs not supported by this class: </p>
697 *
698 * <ul>
699 * <li><p> The backreference constructs, <code>\g{</code><i>n</i><code>}</code> for
700 * the <i>n</i><sup>th</sup><a href="#cg">capturing group</a> and
701 * <code>\g{</code><i>name</i><code>}</code> for
702 * <a href="#groupname">named-capturing group</a>.
703 * </p></li>
704 *
705 * <li><p> The conditional constructs
706 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code )} and
707 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code |}<i>Y</i>{@code )},
708 * </p></li>
709 *
710 * <li><p> The embedded code constructs <code>(?{</code><i>code</i><code>})</code>
711 * and <code>(??{</code><i>code</i><code>})</code>,</p></li>
712 *
713 * <li><p> The embedded comment syntax {@code (?#comment)}, and </p></li>
714 *
715 * <li><p> The preprocessing operations {@code \l} <code>\u</code>,
716 * {@code \L}, and {@code \U}. </p></li>
717 *
718 * </ul>
719 *
720 * <p> Constructs supported by this class but not by Perl: </p>
721 *
722 * <ul>
723 *
724 * <li><p> Character-class union and intersection as described
725 * <a href="#cc">above</a>.</p></li>
726 *
727 * </ul>
728 *
729 * <p> Notable differences from Perl: </p>
730 *
731 * <ul>
732 *
733 * <li><p> In Perl, {@code \1} through {@code \9} are always interpreted
734 * as back references; a backslash-escaped number greater than {@code 9} is
735 * treated as a back reference if at least that many subexpressions exist,
736 * otherwise it is interpreted, if possible, as an octal escape. In this
737 * class octal escapes must always begin with a zero. In this class,
738 * {@code \1} through {@code \9} are always interpreted as back
739 * references, and a larger number is accepted as a back reference if at
740 * least that many subexpressions exist at that point in the regular
741 * expression, otherwise the parser will drop digits until the number is
742 * smaller or equal to the existing number of groups or it is one digit.
743 * </p></li>
744 *
745 * <li><p> Perl uses the {@code g} flag to request a match that resumes
746 * where the last match left off. This functionality is provided implicitly
747 * by the {@link Matcher} class: Repeated invocations of the {@link
748 * Matcher#find find} method will resume where the last match left off,
749 * unless the matcher is reset. </p></li>
750 *
751 * <li><p> In Perl, embedded flags at the top level of an expression affect
752 * the whole expression. In this class, embedded flags always take effect
753 * at the point at which they appear, whether they are at the top level or
754 * within a group; in the latter case, flags are restored at the end of the
755 * group just as in Perl. </p></li>
756 *
757 * </ul>
758 *
759 *
760 * <p> For a more precise description of the behavior of regular expression
761 * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/">
762 * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl,
763 * O'Reilly and Associates, 2006.</a>
764 * </p>
765 *
766 * @see java.lang.String#split(String, int)
767 * @see java.lang.String#split(String)
768 *
769 * @author Mike McCloskey
770 * @author Mark Reinhold
771 * @author JSR-51 Expert Group
772 * @since 1.4
773 * @spec JSR-51
774 */
775
776 public final class Pattern
777 implements java.io.Serializable
778 {
779
780 /**
781 * Regular expression modifier values. Instead of being passed as
782 * arguments, they can also be passed as inline modifiers.
783 * For example, the following statements have the same effect.
784 * <pre>
785 * Pattern p1 = Pattern.compile("abc", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE);
786 * Pattern p2 = Pattern.compile("(?im)abc", 0);
787 * </pre>
788 */
789
790 /**
791 * Enables Unix lines mode.
792 *
793 * <p> In this mode, only the {@code '\n'} line terminator is recognized
794 * in the behavior of {@code .}, {@code ^}, and {@code $}.
795 *
796 * <p> Unix lines mode can also be enabled via the embedded flag
797 * expression {@code (?d)}.
798 */
799 public static final int UNIX_LINES = 0x01;
800
801 /**
802 * Enables case-insensitive matching.
803 *
804 * <p> By default, case-insensitive matching assumes that only characters
805 * in the US-ASCII charset are being matched. Unicode-aware
806 * case-insensitive matching can be enabled by specifying the {@link
807 * #UNICODE_CASE} flag in conjunction with this flag.
808 *
809 * <p> Case-insensitive matching can also be enabled via the embedded flag
810 * expression {@code (?i)}.
811 *
812 * <p> Specifying this flag may impose a slight performance penalty. </p>
813 */
814 public static final int CASE_INSENSITIVE = 0x02;
815
816 /**
817 * Permits whitespace and comments in pattern.
818 *
819 * <p> In this mode, whitespace is ignored, and embedded comments starting
820 * with {@code #} are ignored until the end of a line.
821 *
822 * <p> Comments mode can also be enabled via the embedded flag
823 * expression {@code (?x)}.
824 */
825 public static final int COMMENTS = 0x04;
826
827 /**
828 * Enables multiline mode.
829 *
830 * <p> In multiline mode the expressions {@code ^} and {@code $} match
831 * just after or just before, respectively, a line terminator or the end of
832 * the input sequence. By default these expressions only match at the
833 * beginning and the end of the entire input sequence.
834 *
835 * <p> Multiline mode can also be enabled via the embedded flag
836 * expression {@code (?m)}. </p>
837 */
838 public static final int MULTILINE = 0x08;
839
840 /**
841 * Enables literal parsing of the pattern.
842 *
843 * <p> When this flag is specified then the input string that specifies
844 * the pattern is treated as a sequence of literal characters.
845 * Metacharacters or escape sequences in the input sequence will be
846 * given no special meaning.
847 *
848 * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on
849 * matching when used in conjunction with this flag. The other flags
850 * become superfluous.
851 *
852 * <p> There is no embedded flag character for enabling literal parsing.
853 * @since 1.5
854 */
855 public static final int LITERAL = 0x10;
856
857 /**
858 * Enables dotall mode.
859 *
860 * <p> In dotall mode, the expression {@code .} matches any character,
861 * including a line terminator. By default this expression does not match
862 * line terminators.
863 *
864 * <p> Dotall mode can also be enabled via the embedded flag
865 * expression {@code (?s)}. (The {@code s} is a mnemonic for
866 * "single-line" mode, which is what this is called in Perl.) </p>
867 */
868 public static final int DOTALL = 0x20;
869
870 /**
871 * Enables Unicode-aware case folding.
872 *
873 * <p> When this flag is specified then case-insensitive matching, when
874 * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner
875 * consistent with the Unicode Standard. By default, case-insensitive
876 * matching assumes that only characters in the US-ASCII charset are being
877 * matched.
878 *
879 * <p> Unicode-aware case folding can also be enabled via the embedded flag
880 * expression {@code (?u)}.
881 *
882 * <p> Specifying this flag may impose a performance penalty. </p>
883 */
884 public static final int UNICODE_CASE = 0x40;
885
886 /**
887 * Enables canonical equivalence.
888 *
889 * <p> When this flag is specified then two characters will be considered
890 * to match if, and only if, their full canonical decompositions match.
891 * The expression <code>"a\u030A"</code>, for example, will match the
892 * string <code>"\u00E5"</code> when this flag is specified. By default,
893 * matching does not take canonical equivalence into account.
894 *
895 * <p> There is no embedded flag character for enabling canonical
896 * equivalence.
897 *
898 * <p> Specifying this flag may impose a performance penalty. </p>
899 */
900 public static final int CANON_EQ = 0x80;
901
902 /**
903 * Enables the Unicode version of <i>Predefined character classes</i> and
904 * <i>POSIX character classes</i>.
905 *
906 * <p> When this flag is specified then the (US-ASCII only)
907 * <i>Predefined character classes</i> and <i>POSIX character classes</i>
908 * are in conformance with
909 * <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
910 * Standard #18: Unicode Regular Expression</i></a>
911 * <i>Annex C: Compatibility Properties</i>.
912 * <p>
913 * The UNICODE_CHARACTER_CLASS mode can also be enabled via the embedded
914 * flag expression {@code (?U)}.
915 * <p>
916 * The flag implies UNICODE_CASE, that is, it enables Unicode-aware case
917 * folding.
918 * <p>
919 * Specifying this flag may impose a performance penalty. </p>
920 * @since 1.7
921 */
922 public static final int UNICODE_CHARACTER_CLASS = 0x100;
923
924 /**
925 * Contains all possible flags for compile(regex, flags).
926 */
927 private static final int ALL_FLAGS = CASE_INSENSITIVE | MULTILINE |
928 DOTALL | UNICODE_CASE | CANON_EQ | UNIX_LINES | LITERAL |
929 UNICODE_CHARACTER_CLASS | COMMENTS;
930
931 /* Pattern has only two serialized components: The pattern string
932 * and the flags, which are all that is needed to recompile the pattern
933 * when it is deserialized.
934 */
935
936 /** use serialVersionUID from Merlin b59 for interoperability */
937 private static final long serialVersionUID = 5073258162644648461L;
938
939 /**
940 * The original regular-expression pattern string.
941 *
942 * @serial
943 */
944 private String pattern;
945
946 /**
947 * The original pattern flags.
948 *
949 * @serial
950 */
951 private int flags;
952
953 /**
954 * The temporary pattern flags used during compiling. The flags might be turn
955 * on and off by embedded flag.
956 */
957 private transient int flags0;
958
959 /**
960 * Boolean indicating this Pattern is compiled; this is necessary in order
961 * to lazily compile deserialized Patterns.
962 */
963 private transient volatile boolean compiled;
964
965 /**
966 * The normalized pattern string.
967 */
968 private transient String normalizedPattern;
969
970 /**
971 * The starting point of state machine for the find operation. This allows
972 * a match to start anywhere in the input.
973 */
974 transient Node root;
975
976 /**
977 * The root of object tree for a match operation. The pattern is matched
978 * at the beginning. This may include a find that uses BnM or a First
979 * node.
980 */
981 transient Node matchRoot;
982
983 /**
984 * Temporary storage used by parsing pattern slice.
985 */
986 transient int[] buffer;
987
988 /**
989 * A temporary storage used for predicate for double return.
990 */
991 transient CharPredicate predicate;
992
993 /**
994 * Map the "name" of the "named capturing group" to its group id
995 * node.
996 */
997 transient volatile Map<String, Integer> namedGroups;
998
999 /**
1000 * Temporary storage used while parsing group references.
1001 */
1002 transient GroupHead[] groupNodes;
1003
1004 /**
1005 * Temporary storage used to store the top level closure nodes.
1006 */
1007 transient List<Node> topClosureNodes;
1008
1009 /**
1010 * The number of top greedy closure nodes in this Pattern. Used by
1011 * matchers to allocate storage needed for a IntHashSet to keep the
1012 * beginning pos {@code i} of all failed match.
1013 */
1014 transient int localTCNCount;
1015
1016 /*
1017 * Turn off the stop-exponential-backtracking optimization if there
1018 * is a group ref in the pattern.
1019 */
1020 transient boolean hasGroupRef;
1021
1022 /**
1023 * Temporary null terminated code point array used by pattern compiling.
1024 */
1025 private transient int[] temp;
1026
1027 /**
1028 * The number of capturing groups in this Pattern. Used by matchers to
1029 * allocate storage needed to perform a match.
1030 */
1031 transient int capturingGroupCount;
1032
1033 /**
1034 * The local variable count used by parsing tree. Used by matchers to
1035 * allocate storage needed to perform a match.
1036 */
1037 transient int localCount;
1038
1039 /**
1040 * Index into the pattern string that keeps track of how much has been
1041 * parsed.
1042 */
1043 private transient int cursor;
1044
1045 /**
1046 * Holds the length of the pattern string.
1047 */
1048 private transient int patternLength;
1049
1050 /**
1051 * If the Start node might possibly match supplementary characters.
1052 * It is set to true during compiling if
1053 * (1) There is supplementary char in pattern, or
1054 * (2) There is complement node of a "family" CharProperty
1055 */
1056 private transient boolean hasSupplementary;
1057
1058 /**
1059 * Compiles the given regular expression into a pattern.
1060 *
1061 * @param regex
1062 * The expression to be compiled
1063 * @return the given regular expression compiled into a pattern
1064 * @throws PatternSyntaxException
1065 * If the expression's syntax is invalid
1066 */
1067 public static Pattern compile(String regex) {
1068 return new Pattern(regex, 0);
1069 }
1070
1071 /**
1072 * Compiles the given regular expression into a pattern with the given
1073 * flags.
1074 *
1075 * @param regex
1076 * The expression to be compiled
1077 *
1078 * @param flags
1079 * Match flags, a bit mask that may include
1080 * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
1081 * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
1082 * {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS}
1083 * and {@link #COMMENTS}
1084 *
1085 * @return the given regular expression compiled into a pattern with the given flags
1086 * @throws IllegalArgumentException
1087 * If bit values other than those corresponding to the defined
1088 * match flags are set in {@code flags}
1089 *
1090 * @throws PatternSyntaxException
1091 * If the expression's syntax is invalid
1092 */
1093 public static Pattern compile(String regex, int flags) {
1094 return new Pattern(regex, flags);
1095 }
1096
1097 /**
1098 * Returns the regular expression from which this pattern was compiled.
1099 *
1100 * @return The source of this pattern
1101 */
1102 public String pattern() {
1103 return pattern;
1104 }
1105
1106 /**
1107 * <p>Returns the string representation of this pattern. This
1108 * is the regular expression from which this pattern was
1109 * compiled.</p>
1110 *
1111 * @return The string representation of this pattern
1112 * @since 1.5
1113 */
1114 public String toString() {
1115 return pattern;
1116 }
1117
1118 /**
1119 * Creates a matcher that will match the given input against this pattern.
1120 *
1121 * @param input
1122 * The character sequence to be matched
1123 *
1124 * @return A new matcher for this pattern
1125 */
1126 public Matcher matcher(CharSequence input) {
1127 if (!compiled) {
1128 synchronized(this) {
1129 if (!compiled)
1130 compile();
1131 }
1132 }
1133 Matcher m = new Matcher(this, input);
1134 return m;
1135 }
1136
1137 /**
1138 * Returns this pattern's match flags.
1139 *
1140 * @return The match flags specified when this pattern was compiled
1141 */
1142 public int flags() {
1143 return flags0;
1144 }
1145
1146 /**
1147 * Compiles the given regular expression and attempts to match the given
1148 * input against it.
1149 *
1150 * <p> An invocation of this convenience method of the form
1151 *
1152 * <blockquote><pre>
1153 * Pattern.matches(regex, input);</pre></blockquote>
1154 *
1155 * behaves in exactly the same way as the expression
1156 *
1157 * <blockquote><pre>
1158 * Pattern.compile(regex).matcher(input).matches()</pre></blockquote>
1159 *
1160 * <p> If a pattern is to be used multiple times, compiling it once and reusing
1161 * it will be more efficient than invoking this method each time. </p>
1162 *
1163 * @param regex
1164 * The expression to be compiled
1165 *
1166 * @param input
1167 * The character sequence to be matched
1168 * @return whether or not the regular expression matches on the input
1169 * @throws PatternSyntaxException
1170 * If the expression's syntax is invalid
1171 */
1172 public static boolean matches(String regex, CharSequence input) {
1173 Pattern p = Pattern.compile(regex);
1174 Matcher m = p.matcher(input);
1175 return m.matches();
1176 }
1177
1178 /**
1179 * Splits the given input sequence around matches of this pattern.
1180 *
1181 * <p> The array returned by this method contains each substring of the
1182 * input sequence that is terminated by another subsequence that matches
1183 * this pattern or is terminated by the end of the input sequence. The
1184 * substrings in the array are in the order in which they occur in the
1185 * input. If this pattern does not match any subsequence of the input then
1186 * the resulting array has just one element, namely the input sequence in
1187 * string form.
1188 *
1189 * <p> When there is a positive-width match at the beginning of the input
1190 * sequence then an empty leading substring is included at the beginning
1191 * of the resulting array. A zero-width match at the beginning however
1192 * never produces such empty leading substring.
1193 *
1194 * <p> The {@code limit} parameter controls the number of times the
1195 * pattern is applied and therefore affects the length of the resulting
1196 * array. If the limit <i>n</i> is greater than zero then the pattern
1197 * will be applied at most <i>n</i> - 1 times, the array's
1198 * length will be no greater than <i>n</i>, and the array's last entry
1199 * will contain all input beyond the last matched delimiter. If <i>n</i>
1200 * is non-positive then the pattern will be applied as many times as
1201 * possible and the array can have any length. If <i>n</i> is zero then
1202 * the pattern will be applied as many times as possible, the array can
1203 * have any length, and trailing empty strings will be discarded.
1204 *
1205 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1206 * results with these parameters:
1207 *
1208 * <table class="plain" style="margin-left:2em;">
1209 * <caption style="display:none">Split example showing regex, limit, and result</caption>
1210 * <thead>
1211 * <tr>
1212 * <th scope="col">Regex</th>
1213 * <th scope="col">Limit</th>
1214 * <th scope="col">Result</th>
1215 * </tr>
1216 * </thead>
1217 * <tbody>
1218 * <tr><th scope="row" rowspan="3" style="font-weight:normal">:</th>
1219 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">2</th>
1220 * <td>{@code { "boo", "and:foo" }}</td></tr>
1221 * <tr><!-- : -->
1222 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th>
1223 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1224 * <tr><!-- : -->
1225 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th>
1226 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1227 * <tr><th scope="row" rowspan="3" style="font-weight:normal">o</th>
1228 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th>
1229 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1230 * <tr><!-- o -->
1231 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th>
1232 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1233 * <tr><!-- o -->
1234 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">0</th>
1235 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1236 * </tbody>
1237 * </table>
1238 *
1239 * @param input
1240 * The character sequence to be split
1241 *
1242 * @param limit
1243 * The result threshold, as described above
1244 *
1245 * @return The array of strings computed by splitting the input
1246 * around matches of this pattern
1247 */
1248 public String[] split(CharSequence input, int limit) {
1249 int index = 0;
1250 boolean matchLimited = limit > 0;
1251 ArrayList<String> matchList = new ArrayList<>();
1252 Matcher m = matcher(input);
1253
1254 // Add segments before each match found
1255 while(m.find()) {
1256 if (!matchLimited || matchList.size() < limit - 1) {
1257 if (index == 0 && index == m.start() && m.start() == m.end()) {
1258 // no empty leading substring included for zero-width match
1259 // at the beginning of the input char sequence.
1260 continue;
1261 }
1262 String match = input.subSequence(index, m.start()).toString();
1263 matchList.add(match);
1264 index = m.end();
1265 } else if (matchList.size() == limit - 1) { // last one
1266 String match = input.subSequence(index,
1267 input.length()).toString();
1268 matchList.add(match);
1269 index = m.end();
1270 }
1271 }
1272
1273 // If no match was found, return this
1274 if (index == 0)
1275 return new String[] {input.toString()};
1276
1277 // Add remaining segment
1278 if (!matchLimited || matchList.size() < limit)
1279 matchList.add(input.subSequence(index, input.length()).toString());
1280
1281 // Construct result
1282 int resultSize = matchList.size();
1283 if (limit == 0)
1284 while (resultSize > 0 && matchList.get(resultSize-1).equals(""))
1285 resultSize--;
1286 String[] result = new String[resultSize];
1287 return matchList.subList(0, resultSize).toArray(result);
1288 }
1289
1290 /**
1291 * Splits the given input sequence around matches of this pattern.
1292 *
1293 * <p> This method works as if by invoking the two-argument {@link
1294 * #split(java.lang.CharSequence, int) split} method with the given input
1295 * sequence and a limit argument of zero. Trailing empty strings are
1296 * therefore not included in the resulting array. </p>
1297 *
1298 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1299 * results with these expressions:
1300 *
1301 * <table class="plain" style="margin-left:2em">
1302 * <caption style="display:none">Split examples showing regex and result</caption>
1303 * <thead>
1304 * <tr>
1305 * <th scope="col">Regex</th>
1306 * <th scope="col">Result</th>
1307 * </tr>
1308 * </thead>
1309 * <tbody>
1310 * <tr><th scope="row" style="text-weight:normal">:</th>
1311 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1312 * <tr><th scope="row" style="text-weight:normal">o</th>
1313 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1314 * </tbody>
1315 * </table>
1316 *
1317 *
1318 * @param input
1319 * The character sequence to be split
1320 *
1321 * @return The array of strings computed by splitting the input
1322 * around matches of this pattern
1323 */
1324 public String[] split(CharSequence input) {
1325 return split(input, 0);
1326 }
1327
1328 /**
1329 * Returns a literal pattern {@code String} for the specified
1330 * {@code String}.
1331 *
1332 * <p>This method produces a {@code String} that can be used to
1333 * create a {@code Pattern} that would match the string
1334 * {@code s} as if it were a literal pattern.</p> Metacharacters
1335 * or escape sequences in the input sequence will be given no special
1336 * meaning.
1337 *
1338 * @param s The string to be literalized
1339 * @return A literal string replacement
1340 * @since 1.5
1341 */
1342 public static String quote(String s) {
1343 int slashEIndex = s.indexOf("\\E");
1344 if (slashEIndex == -1)
1345 return "\\Q" + s + "\\E";
1346
1347 int lenHint = s.length();
1348 lenHint = (lenHint < Integer.MAX_VALUE - 8 - lenHint) ?
1349 (lenHint << 1) : (Integer.MAX_VALUE - 8);
1350
1351 StringBuilder sb = new StringBuilder(lenHint);
1352 sb.append("\\Q");
1353 int current = 0;
1354 do {
1355 sb.append(s, current, slashEIndex)
1356 .append("\\E\\\\E\\Q");
1357 current = slashEIndex + 2;
1358 } while ((slashEIndex = s.indexOf("\\E", current)) != -1);
1359
1360 return sb.append(s, current, s.length())
1361 .append("\\E")
1362 .toString();
1363 }
1364
1365 /**
1366 * Recompile the Pattern instance from a stream. The original pattern
1367 * string is read in and the object tree is recompiled from it.
1368 */
1369 private void readObject(java.io.ObjectInputStream s)
1370 throws java.io.IOException, ClassNotFoundException {
1371
1372 // Read in all fields
1373 s.defaultReadObject();
1374
1375 // reset the flags
1376 flags0 = flags;
1377
1378 // Initialize counts
1379 capturingGroupCount = 1;
1380 localCount = 0;
1381 localTCNCount = 0;
1382
1383 // if length > 0, the Pattern is lazily compiled
1384 if (pattern.length() == 0) {
1385 root = new Start(lastAccept);
1386 matchRoot = lastAccept;
1387 compiled = true;
1388 }
1389 }
1390
1391 /**
1392 * This private constructor is used to create all Patterns. The pattern
1393 * string and match flags are all that is needed to completely describe
1394 * a Pattern. An empty pattern string results in an object tree with
1395 * only a Start node and a LastNode node.
1396 */
1397 private Pattern(String p, int f) {
1398 if ((f & ~ALL_FLAGS) != 0) {
1399 throw new IllegalArgumentException("Unknown flag 0x"
1400 + Integer.toHexString(f));
1401 }
1402 pattern = p;
1403 flags = f;
1404
1405 // to use UNICODE_CASE if UNICODE_CHARACTER_CLASS present
1406 if ((flags & UNICODE_CHARACTER_CLASS) != 0)
1407 flags |= UNICODE_CASE;
1408
1409 // 'flags' for compiling
1410 flags0 = flags;
1411
1412 // Reset group index count
1413 capturingGroupCount = 1;
1414 localCount = 0;
1415 localTCNCount = 0;
1416
1417 if (pattern.length() > 0) {
1418 compile();
1419 } else {
1420 root = new Start(lastAccept);
1421 matchRoot = lastAccept;
1422 }
1423 }
1424
1425 /**
1426 * The pattern is converted to normalized form ({@link
1427 * java.text.Normalizer.Form.NFC NFC}, canonical decomposition,
1428 * followed by canonical composition for the character class
1429 * part, and {@link java.text.Normalizer.Form.NFD NFD},
1430 * canonical decomposition) for the rest), and then a pure
1431 * group is constructed to match canonical equivalences of the
1432 * characters.
1433 */
1434 private static String normalize(String pattern) {
1435 int plen = pattern.length();
1436 StringBuilder pbuf = new StringBuilder(plen);
1437 char last = 0;
1438 int lastStart = 0;
1439 char cc = 0;
1440 for (int i = 0; i < plen;) {
1441 char c = pattern.charAt(i);
1442 if (cc == 0 && // top level
1443 c == '\\' && i + 1 < plen && pattern.charAt(i + 1) == '\\') {
1444 i += 2; last = 0;
1445 continue;
1446 }
1447 if (c == '[' && last != '\\') {
1448 if (cc == 0) {
1449 if (lastStart < i)
1450 normalizeSlice(pattern, lastStart, i, pbuf);
1451 lastStart = i;
1452 }
1453 cc++;
1454 } else if (c == ']' && last != '\\') {
1455 cc--;
1456 if (cc == 0) {
1457 normalizeClazz(pattern, lastStart, i + 1, pbuf);
1458 lastStart = i + 1;
1459 }
1460 }
1461 last = c;
1462 i++;
1463 }
1464 assert (cc == 0);
1465 if (lastStart < plen)
1466 normalizeSlice(pattern, lastStart, plen, pbuf);
1467 return pbuf.toString();
1468 }
1469
1470 private static void normalizeSlice(String src, int off, int limit,
1471 StringBuilder dst)
1472 {
1473 int len = src.length();
1474 int off0 = off;
1475 while (off < limit && ASCII.isAscii(src.charAt(off))) {
1476 off++;
1477 }
1478 if (off == limit) {
1479 dst.append(src, off0, limit);
1480 return;
1481 }
1482 off--;
1483 if (off < off0)
1484 off = off0;
1485 else
1486 dst.append(src, off0, off);
1487 while (off < limit) {
1488 int ch0 = src.codePointAt(off);
1489 if (".$|()[]{}^?*+\\".indexOf(ch0) != -1) {
1490 dst.append((char)ch0);
1491 off++;
1492 continue;
1493 }
1494 int j = off + Character.charCount(ch0);
1495 int ch1;
1496 while (j < limit) {
1497 ch1 = src.codePointAt(j);
1498 if (Grapheme.isBoundary(ch0, ch1))
1499 break;
1500 ch0 = ch1;
1501 j += Character.charCount(ch1);
1502 }
1503 String seq = src.substring(off, j);
1504 String nfd = Normalizer.normalize(seq, Normalizer.Form.NFD);
1505 off = j;
1506 if (nfd.length() > 1) {
1507 ch0 = nfd.codePointAt(0);
1508 ch1 = nfd.codePointAt(Character.charCount(ch0));
1509 if (Character.getType(ch1) == Character.NON_SPACING_MARK) {
1510 Set<String> altns = new LinkedHashSet<>();
1511 altns.add(seq);
1512 produceEquivalentAlternation(nfd, altns);
1513 dst.append("(?:");
1514 altns.forEach( s -> dst.append(s).append('|'));
1515 dst.delete(dst.length() - 1, dst.length());
1516 dst.append(")");
1517 continue;
1518 }
1519 }
1520 String nfc = Normalizer.normalize(seq, Normalizer.Form.NFC);
1521 if (!seq.equals(nfc) && !nfd.equals(nfc))
1522 dst.append("(?:" + seq + "|" + nfd + "|" + nfc + ")");
1523 else if (!seq.equals(nfd))
1524 dst.append("(?:" + seq + "|" + nfd + ")");
1525 else
1526 dst.append(seq);
1527 }
1528 }
1529
1530 private static void normalizeClazz(String src, int off, int limit,
1531 StringBuilder dst)
1532 {
1533 dst.append(Normalizer.normalize(src.substring(off, limit), Form.NFC));
1534 }
1535
1536 /**
1537 * Given a specific sequence composed of a regular character and
1538 * combining marks that follow it, produce the alternation that will
1539 * match all canonical equivalences of that sequence.
1540 */
1541 private static void produceEquivalentAlternation(String src,
1542 Set<String> dst)
1543 {
1544 int len = countChars(src, 0, 1);
1545 if (src.length() == len) {
1546 dst.add(src); // source has one character.
1547 return;
1548 }
1549 String base = src.substring(0,len);
1550 String combiningMarks = src.substring(len);
1551 String[] perms = producePermutations(combiningMarks);
1552 // Add combined permutations
1553 for(int x = 0; x < perms.length; x++) {
1554 String next = base + perms[x];
1555 dst.add(next);
1556 next = composeOneStep(next);
1557 if (next != null) {
1558 produceEquivalentAlternation(next, dst);
1559 }
1560 }
1561 }
1562
1563 /**
1564 * Returns an array of strings that have all the possible
1565 * permutations of the characters in the input string.
1566 * This is used to get a list of all possible orderings
1567 * of a set of combining marks. Note that some of the permutations
1568 * are invalid because of combining class collisions, and these
1569 * possibilities must be removed because they are not canonically
1570 * equivalent.
1571 */
1572 private static String[] producePermutations(String input) {
1573 if (input.length() == countChars(input, 0, 1))
1574 return new String[] {input};
1575
1576 if (input.length() == countChars(input, 0, 2)) {
1577 int c0 = Character.codePointAt(input, 0);
1578 int c1 = Character.codePointAt(input, Character.charCount(c0));
1579 if (getClass(c1) == getClass(c0)) {
1580 return new String[] {input};
1581 }
1582 String[] result = new String[2];
1583 result[0] = input;
1584 StringBuilder sb = new StringBuilder(2);
1585 sb.appendCodePoint(c1);
1586 sb.appendCodePoint(c0);
1587 result[1] = sb.toString();
1588 return result;
1589 }
1590
1591 int length = 1;
1592 int nCodePoints = countCodePoints(input);
1593 for(int x=1; x<nCodePoints; x++)
1594 length = length * (x+1);
1595
1596 String[] temp = new String[length];
1597
1598 int combClass[] = new int[nCodePoints];
1599 for(int x=0, i=0; x<nCodePoints; x++) {
1600 int c = Character.codePointAt(input, i);
1601 combClass[x] = getClass(c);
1602 i += Character.charCount(c);
1603 }
1604
1605 // For each char, take it out and add the permutations
1606 // of the remaining chars
1607 int index = 0;
1608 int len;
1609 // offset maintains the index in code units.
1610 loop: for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
1611 len = countChars(input, offset, 1);
1612 for(int y=x-1; y>=0; y--) {
1613 if (combClass[y] == combClass[x]) {
1614 continue loop;
1615 }
1616 }
1617 StringBuilder sb = new StringBuilder(input);
1618 String otherChars = sb.delete(offset, offset+len).toString();
1619 String[] subResult = producePermutations(otherChars);
1620
1621 String prefix = input.substring(offset, offset+len);
1622 for (String sre : subResult)
1623 temp[index++] = prefix + sre;
1624 }
1625 String[] result = new String[index];
1626 System.arraycopy(temp, 0, result, 0, index);
1627 return result;
1628 }
1629
1630 private static int getClass(int c) {
1631 return sun.text.Normalizer.getCombiningClass(c);
1632 }
1633
1634 /**
1635 * Attempts to compose input by combining the first character
1636 * with the first combining mark following it. Returns a String
1637 * that is the composition of the leading character with its first
1638 * combining mark followed by the remaining combining marks. Returns
1639 * null if the first two characters cannot be further composed.
1640 */
1641 private static String composeOneStep(String input) {
1642 int len = countChars(input, 0, 2);
1643 String firstTwoCharacters = input.substring(0, len);
1644 String result = Normalizer.normalize(firstTwoCharacters, Normalizer.Form.NFC);
1645 if (result.equals(firstTwoCharacters))
1646 return null;
1647 else {
1648 String remainder = input.substring(len);
1649 return result + remainder;
1650 }
1651 }
1652
1653 /**
1654 * Preprocess any \Q...\E sequences in `temp', meta-quoting them.
1655 * See the description of `quotemeta' in perlfunc(1).
1656 */
1657 private void RemoveQEQuoting() {
1658 final int pLen = patternLength;
1659 int i = 0;
1660 while (i < pLen-1) {
1661 if (temp[i] != '\\')
1662 i += 1;
1663 else if (temp[i + 1] != 'Q')
1664 i += 2;
1665 else
1666 break;
1667 }
1668 if (i >= pLen - 1) // No \Q sequence found
1669 return;
1670 int j = i;
1671 i += 2;
1672 int[] newtemp = new int[j + 3*(pLen-i) + 2];
1673 System.arraycopy(temp, 0, newtemp, 0, j);
1674
1675 boolean inQuote = true;
1676 boolean beginQuote = true;
1677 while (i < pLen) {
1678 int c = temp[i++];
1679 if (!ASCII.isAscii(c) || ASCII.isAlpha(c)) {
1680 newtemp[j++] = c;
1681 } else if (ASCII.isDigit(c)) {
1682 if (beginQuote) {
1683 /*
1684 * A unicode escape \[0xu] could be before this quote,
1685 * and we don't want this numeric char to processed as
1686 * part of the escape.
1687 */
1688 newtemp[j++] = '\\';
1689 newtemp[j++] = 'x';
1690 newtemp[j++] = '3';
1691 }
1692 newtemp[j++] = c;
1693 } else if (c != '\\') {
1694 if (inQuote) newtemp[j++] = '\\';
1695 newtemp[j++] = c;
1696 } else if (inQuote) {
1697 if (temp[i] == 'E') {
1698 i++;
1699 inQuote = false;
1700 } else {
1701 newtemp[j++] = '\\';
1702 newtemp[j++] = '\\';
1703 }
1704 } else {
1705 if (temp[i] == 'Q') {
1706 i++;
1707 inQuote = true;
1708 beginQuote = true;
1709 continue;
1710 } else {
1711 newtemp[j++] = c;
1712 if (i != pLen)
1713 newtemp[j++] = temp[i++];
1714 }
1715 }
1716
1717 beginQuote = false;
1718 }
1719
1720 patternLength = j;
1721 temp = Arrays.copyOf(newtemp, j + 2); // double zero termination
1722 }
1723
1724 /**
1725 * Copies regular expression to an int array and invokes the parsing
1726 * of the expression which will create the object tree.
1727 */
1728 private void compile() {
1729 // Handle canonical equivalences
1730 if (has(CANON_EQ) && !has(LITERAL)) {
1731 normalizedPattern = normalize(pattern);
1732 } else {
1733 normalizedPattern = pattern;
1734 }
1735 patternLength = normalizedPattern.length();
1736
1737 // Copy pattern to int array for convenience
1738 // Use double zero to terminate pattern
1739 temp = new int[patternLength + 2];
1740
1741 hasSupplementary = false;
1742 int c, count = 0;
1743 // Convert all chars into code points
1744 for (int x = 0; x < patternLength; x += Character.charCount(c)) {
1745 c = normalizedPattern.codePointAt(x);
1746 if (isSupplementary(c)) {
1747 hasSupplementary = true;
1748 }
1749 temp[count++] = c;
1750 }
1751
1752 patternLength = count; // patternLength now in code points
1753
1754 if (! has(LITERAL))
1755 RemoveQEQuoting();
1756
1757 // Allocate all temporary objects here.
1758 buffer = new int[32];
1759 groupNodes = new GroupHead[10];
1760 namedGroups = null;
1761 topClosureNodes = new ArrayList<>(10);
1762
1763 if (has(LITERAL)) {
1764 // Literal pattern handling
1765 matchRoot = newSlice(temp, patternLength, hasSupplementary);
1766 matchRoot.next = lastAccept;
1767 } else {
1768 // Start recursive descent parsing
1769 matchRoot = expr(lastAccept);
1770 // Check extra pattern characters
1771 if (patternLength != cursor) {
1772 if (peek() == ')') {
1773 throw error("Unmatched closing ')'");
1774 } else {
1775 throw error("Unexpected internal error");
1776 }
1777 }
1778 }
1779
1780 // Peephole optimization
1781 if (matchRoot instanceof Slice) {
1782 root = BnM.optimize(matchRoot);
1783 if (root == matchRoot) {
1784 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1785 }
1786 } else if (matchRoot instanceof Begin || matchRoot instanceof First) {
1787 root = matchRoot;
1788 } else {
1789 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1790 }
1791
1792 // Optimize the greedy Loop to prevent exponential backtracking, IF there
1793 // is no group ref in this pattern. With a non-negative localTCNCount value,
1794 // the greedy type Loop, Curly will skip the backtracking for any starting
1795 // position "i" that failed in the past.
1796 if (!hasGroupRef) {
1797 for (Node node : topClosureNodes) {
1798 if (node instanceof Loop) {
1799 // non-deterministic-greedy-group
1800 ((Loop)node).posIndex = localTCNCount++;
1801 }
1802 }
1803 }
1804
1805 // Release temporary storage
1806 temp = null;
1807 buffer = null;
1808 groupNodes = null;
1809 patternLength = 0;
1810 compiled = true;
1811 topClosureNodes = null;
1812 }
1813
1814 Map<String, Integer> namedGroups() {
1815 Map<String, Integer> groups = namedGroups;
1816 if (groups == null) {
1817 namedGroups = groups = new HashMap<>(2);
1818 }
1819 return groups;
1820 }
1821
1822 /**
1823 * Used to accumulate information about a subtree of the object graph
1824 * so that optimizations can be applied to the subtree.
1825 */
1826 static final class TreeInfo {
1827 int minLength;
1828 int maxLength;
1829 boolean maxValid;
1830 boolean deterministic;
1831
1832 TreeInfo() {
1833 reset();
1834 }
1835 void reset() {
1836 minLength = 0;
1837 maxLength = 0;
1838 maxValid = true;
1839 deterministic = true;
1840 }
1841 }
1842
1843 /*
1844 * The following private methods are mainly used to improve the
1845 * readability of the code. In order to let the Java compiler easily
1846 * inline them, we should not put many assertions or error checks in them.
1847 */
1848
1849 /**
1850 * Indicates whether a particular flag is set or not.
1851 */
1852 private boolean has(int f) {
1853 return (flags0 & f) != 0;
1854 }
1855
1856 /**
1857 * Match next character, signal error if failed.
1858 */
1859 private void accept(int ch, String s) {
1860 int testChar = temp[cursor++];
1861 if (has(COMMENTS))
1862 testChar = parsePastWhitespace(testChar);
1863 if (ch != testChar) {
1864 throw error(s);
1865 }
1866 }
1867
1868 /**
1869 * Mark the end of pattern with a specific character.
1870 */
1871 private void mark(int c) {
1872 temp[patternLength] = c;
1873 }
1874
1875 /**
1876 * Peek the next character, and do not advance the cursor.
1877 */
1878 private int peek() {
1879 int ch = temp[cursor];
1880 if (has(COMMENTS))
1881 ch = peekPastWhitespace(ch);
1882 return ch;
1883 }
1884
1885 /**
1886 * Read the next character, and advance the cursor by one.
1887 */
1888 private int read() {
1889 int ch = temp[cursor++];
1890 if (has(COMMENTS))
1891 ch = parsePastWhitespace(ch);
1892 return ch;
1893 }
1894
1895 /**
1896 * Read the next character, and advance the cursor by one,
1897 * ignoring the COMMENTS setting
1898 */
1899 private int readEscaped() {
1900 int ch = temp[cursor++];
1901 return ch;
1902 }
1903
1904 /**
1905 * Advance the cursor by one, and peek the next character.
1906 */
1907 private int next() {
1908 int ch = temp[++cursor];
1909 if (has(COMMENTS))
1910 ch = peekPastWhitespace(ch);
1911 return ch;
1912 }
1913
1914 /**
1915 * Advance the cursor by one, and peek the next character,
1916 * ignoring the COMMENTS setting
1917 */
1918 private int nextEscaped() {
1919 int ch = temp[++cursor];
1920 return ch;
1921 }
1922
1923 /**
1924 * If in xmode peek past whitespace and comments.
1925 */
1926 private int peekPastWhitespace(int ch) {
1927 while (ASCII.isSpace(ch) || ch == '#') {
1928 while (ASCII.isSpace(ch))
1929 ch = temp[++cursor];
1930 if (ch == '#') {
1931 ch = peekPastLine();
1932 }
1933 }
1934 return ch;
1935 }
1936
1937 /**
1938 * If in xmode parse past whitespace and comments.
1939 */
1940 private int parsePastWhitespace(int ch) {
1941 while (ASCII.isSpace(ch) || ch == '#') {
1942 while (ASCII.isSpace(ch))
1943 ch = temp[cursor++];
1944 if (ch == '#')
1945 ch = parsePastLine();
1946 }
1947 return ch;
1948 }
1949
1950 /**
1951 * xmode parse past comment to end of line.
1952 */
1953 private int parsePastLine() {
1954 int ch = temp[cursor++];
1955 while (ch != 0 && !isLineSeparator(ch))
1956 ch = temp[cursor++];
1957 return ch;
1958 }
1959
1960 /**
1961 * xmode peek past comment to end of line.
1962 */
1963 private int peekPastLine() {
1964 int ch = temp[++cursor];
1965 while (ch != 0 && !isLineSeparator(ch))
1966 ch = temp[++cursor];
1967 return ch;
1968 }
1969
1970 /**
1971 * Determines if character is a line separator in the current mode
1972 */
1973 private boolean isLineSeparator(int ch) {
1974 if (has(UNIX_LINES)) {
1975 return ch == '\n';
1976 } else {
1977 return (ch == '\n' ||
1978 ch == '\r' ||
1979 (ch|1) == '\u2029' ||
1980 ch == '\u0085');
1981 }
1982 }
1983
1984 /**
1985 * Read the character after the next one, and advance the cursor by two.
1986 */
1987 private int skip() {
1988 int i = cursor;
1989 int ch = temp[i+1];
1990 cursor = i + 2;
1991 return ch;
1992 }
1993
1994 /**
1995 * Unread one next character, and retreat cursor by one.
1996 */
1997 private void unread() {
1998 cursor--;
1999 }
2000
2001 /**
2002 * Internal method used for handling all syntax errors. The pattern is
2003 * displayed with a pointer to aid in locating the syntax error.
2004 */
2005 private PatternSyntaxException error(String s) {
2006 return new PatternSyntaxException(s, normalizedPattern, cursor - 1);
2007 }
2008
2009 /**
2010 * Determines if there is any supplementary character or unpaired
2011 * surrogate in the specified range.
2012 */
2013 private boolean findSupplementary(int start, int end) {
2014 for (int i = start; i < end; i++) {
2015 if (isSupplementary(temp[i]))
2016 return true;
2017 }
2018 return false;
2019 }
2020
2021 /**
2022 * Determines if the specified code point is a supplementary
2023 * character or unpaired surrogate.
2024 */
2025 private static final boolean isSupplementary(int ch) {
2026 return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT ||
2027 Character.isSurrogate((char)ch);
2028 }
2029
2030 /**
2031 * The following methods handle the main parsing. They are sorted
2032 * according to their precedence order, the lowest one first.
2033 */
2034
2035 /**
2036 * The expression is parsed with branch nodes added for alternations.
2037 * This may be called recursively to parse sub expressions that may
2038 * contain alternations.
2039 */
2040 private Node expr(Node end) {
2041 Node prev = null;
2042 Node firstTail = null;
2043 Branch branch = null;
2044 Node branchConn = null;
2045
2046 for (;;) {
2047 Node node = sequence(end);
2048 Node nodeTail = root; //double return
2049 if (prev == null) {
2050 prev = node;
2051 firstTail = nodeTail;
2052 } else {
2053 // Branch
2054 if (branchConn == null) {
2055 branchConn = new BranchConn();
2056 branchConn.next = end;
2057 }
2058 if (node == end) {
2059 // if the node returned from sequence() is "end"
2060 // we have an empty expr, set a null atom into
2061 // the branch to indicate to go "next" directly.
2062 node = null;
2063 } else {
2064 // the "tail.next" of each atom goes to branchConn
2065 nodeTail.next = branchConn;
2066 }
2067 if (prev == branch) {
2068 branch.add(node);
2069 } else {
2070 if (prev == end) {
2071 prev = null;
2072 } else {
2073 // replace the "end" with "branchConn" at its tail.next
2074 // when put the "prev" into the branch as the first atom.
2075 firstTail.next = branchConn;
2076 }
2077 prev = branch = new Branch(prev, node, branchConn);
2078 }
2079 }
2080 if (peek() != '|') {
2081 return prev;
2082 }
2083 next();
2084 }
2085 }
2086
2087 @SuppressWarnings("fallthrough")
2088 /**
2089 * Parsing of sequences between alternations.
2090 */
2091 private Node sequence(Node end) {
2092 Node head = null;
2093 Node tail = null;
2094 Node node = null;
2095 LOOP:
2096 for (;;) {
2097 int ch = peek();
2098 switch (ch) {
2099 case '(':
2100 // Because group handles its own closure,
2101 // we need to treat it differently
2102 node = group0();
2103 // Check for comment or flag group
2104 if (node == null)
2105 continue;
2106 if (head == null)
2107 head = node;
2108 else
2109 tail.next = node;
2110 // Double return: Tail was returned in root
2111 tail = root;
2112 continue;
2113 case '[':
2114 if (has(CANON_EQ) && !has(LITERAL))
2115 node = new NFCCharProperty(clazz(true));
2116 else
2117 node = newCharProperty(clazz(true));
2118 break;
2119 case '\\':
2120 ch = nextEscaped();
2121 if (ch == 'p' || ch == 'P') {
2122 boolean oneLetter = true;
2123 boolean comp = (ch == 'P');
2124 ch = next(); // Consume { if present
2125 if (ch != '{') {
2126 unread();
2127 } else {
2128 oneLetter = false;
2129 }
2130 // node = newCharProperty(family(oneLetter, comp));
2131 if (has(CANON_EQ) && !has(LITERAL))
2132 node = new NFCCharProperty(family(oneLetter, comp));
2133 else
2134 node = newCharProperty(family(oneLetter, comp));
2135 } else {
2136 unread();
2137 node = atom();
2138 }
2139 break;
2140 case '^':
2141 next();
2142 if (has(MULTILINE)) {
2143 if (has(UNIX_LINES))
2144 node = new UnixCaret();
2145 else
2146 node = new Caret();
2147 } else {
2148 node = new Begin();
2149 }
2150 break;
2151 case '$':
2152 next();
2153 if (has(UNIX_LINES))
2154 node = new UnixDollar(has(MULTILINE));
2155 else
2156 node = new Dollar(has(MULTILINE));
2157 break;
2158 case '.':
2159 next();
2160 if (has(DOTALL)) {
2161 node = new CharProperty(ALL());
2162 } else {
2163 if (has(UNIX_LINES)) {
2164 node = new CharProperty(UNIXDOT());
2165 } else {
2166 node = new CharProperty(DOT());
2167 }
2168 }
2169 break;
2170 case '|':
2171 case ')':
2172 break LOOP;
2173 case ']': // Now interpreting dangling ] and } as literals
2174 case '}':
2175 node = atom();
2176 break;
2177 case '?':
2178 case '*':
2179 case '+':
2180 next();
2181 throw error("Dangling meta character '" + ((char)ch) + "'");
2182 case 0:
2183 if (cursor >= patternLength) {
2184 break LOOP;
2185 }
2186 // Fall through
2187 default:
2188 node = atom();
2189 break;
2190 }
2191
2192 node = closure(node);
2193 /* save the top dot-greedy nodes (.*, .+) as well
2194 if (node instanceof GreedyCharProperty &&
2195 ((GreedyCharProperty)node).cp instanceof Dot) {
2196 topClosureNodes.add(node);
2197 }
2198 */
2199 if (head == null) {
2200 head = tail = node;
2201 } else {
2202 tail.next = node;
2203 tail = node;
2204 }
2205 }
2206 if (head == null) {
2207 return end;
2208 }
2209 tail.next = end;
2210 root = tail; //double return
2211 return head;
2212 }
2213
2214 @SuppressWarnings("fallthrough")
2215 /**
2216 * Parse and add a new Single or Slice.
2217 */
2218 private Node atom() {
2219 int first = 0;
2220 int prev = -1;
2221 boolean hasSupplementary = false;
2222 int ch = peek();
2223 for (;;) {
2224 switch (ch) {
2225 case '*':
2226 case '+':
2227 case '?':
2228 case '{':
2229 if (first > 1) {
2230 cursor = prev; // Unwind one character
2231 first--;
2232 }
2233 break;
2234 case '$':
2235 case '.':
2236 case '^':
2237 case '(':
2238 case '[':
2239 case '|':
2240 case ')':
2241 break;
2242 case '\\':
2243 ch = nextEscaped();
2244 if (ch == 'p' || ch == 'P') { // Property
2245 if (first > 0) { // Slice is waiting; handle it first
2246 unread();
2247 break;
2248 } else { // No slice; just return the family node
2249 boolean comp = (ch == 'P');
2250 boolean oneLetter = true;
2251 ch = next(); // Consume { if present
2252 if (ch != '{')
2253 unread();
2254 else
2255 oneLetter = false;
2256 if (has(CANON_EQ) && !has(LITERAL))
2257 return new NFCCharProperty(family(oneLetter, comp));
2258 else
2259 return newCharProperty(family(oneLetter, comp));
2260 }
2261 }
2262 unread();
2263 prev = cursor;
2264 ch = escape(false, first == 0, false);
2265 if (ch >= 0) {
2266 append(ch, first);
2267 first++;
2268 if (isSupplementary(ch)) {
2269 hasSupplementary = true;
2270 }
2271 ch = peek();
2272 continue;
2273 } else if (first == 0) {
2274 return root;
2275 }
2276 // Unwind meta escape sequence
2277 cursor = prev;
2278 break;
2279 case 0:
2280 if (cursor >= patternLength) {
2281 break;
2282 }
2283 // Fall through
2284 default:
2285 prev = cursor;
2286 append(ch, first);
2287 first++;
2288 if (isSupplementary(ch)) {
2289 hasSupplementary = true;
2290 }
2291 ch = next();
2292 continue;
2293 }
2294 break;
2295 }
2296 if (first == 1) {
2297 return newCharProperty(single(buffer[0]));
2298 } else {
2299 return newSlice(buffer, first, hasSupplementary);
2300 }
2301 }
2302
2303 private void append(int ch, int len) {
2304 if (len >= buffer.length) {
2305 int[] tmp = new int[len+len];
2306 System.arraycopy(buffer, 0, tmp, 0, len);
2307 buffer = tmp;
2308 }
2309 buffer[len] = ch;
2310 }
2311
2312 /**
2313 * Parses a backref greedily, taking as many numbers as it
2314 * can. The first digit is always treated as a backref, but
2315 * multi digit numbers are only treated as a backref if at
2316 * least that many backrefs exist at this point in the regex.
2317 */
2318 private Node ref(int refNum) {
2319 boolean done = false;
2320 while(!done) {
2321 int ch = peek();
2322 switch(ch) {
2323 case '0':
2324 case '1':
2325 case '2':
2326 case '3':
2327 case '4':
2328 case '5':
2329 case '6':
2330 case '7':
2331 case '8':
2332 case '9':
2333 int newRefNum = (refNum * 10) + (ch - '0');
2334 // Add another number if it doesn't make a group
2335 // that doesn't exist
2336 if (capturingGroupCount - 1 < newRefNum) {
2337 done = true;
2338 break;
2339 }
2340 refNum = newRefNum;
2341 read();
2342 break;
2343 default:
2344 done = true;
2345 break;
2346 }
2347 }
2348 hasGroupRef = true;
2349 if (has(CASE_INSENSITIVE))
2350 return new CIBackRef(refNum, has(UNICODE_CASE));
2351 else
2352 return new BackRef(refNum);
2353 }
2354
2355 /**
2356 * Parses an escape sequence to determine the actual value that needs
2357 * to be matched.
2358 * If -1 is returned and create was true a new object was added to the tree
2359 * to handle the escape sequence.
2360 * If the returned value is greater than zero, it is the value that
2361 * matches the escape sequence.
2362 */
2363 private int escape(boolean inclass, boolean create, boolean isrange) {
2364 int ch = skip();
2365 switch (ch) {
2366 case '0':
2367 return o();
2368 case '1':
2369 case '2':
2370 case '3':
2371 case '4':
2372 case '5':
2373 case '6':
2374 case '7':
2375 case '8':
2376 case '9':
2377 if (inclass) break;
2378 if (create) {
2379 root = ref((ch - '0'));
2380 }
2381 return -1;
2382 case 'A':
2383 if (inclass) break;
2384 if (create) root = new Begin();
2385 return -1;
2386 case 'B':
2387 if (inclass) break;
2388 if (create) root = new Bound(Bound.NONE, has(UNICODE_CHARACTER_CLASS));
2389 return -1;
2390 case 'C':
2391 break;
2392 case 'D':
2393 if (create) {
2394 predicate = has(UNICODE_CHARACTER_CLASS) ?
2395 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2396 predicate = predicate.negate();
2397 if (!inclass)
2398 root = newCharProperty(predicate);
2399 }
2400 return -1;
2401 case 'E':
2402 case 'F':
2403 break;
2404 case 'G':
2405 if (inclass) break;
2406 if (create) root = new LastMatch();
2407 return -1;
2408 case 'H':
2409 if (create) {
2410 predicate = HorizWS().negate();
2411 if (!inclass)
2412 root = newCharProperty(predicate);
2413 }
2414 return -1;
2415 case 'I':
2416 case 'J':
2417 case 'K':
2418 case 'L':
2419 case 'M':
2420 break;
2421 case 'N':
2422 return N();
2423 case 'O':
2424 case 'P':
2425 case 'Q':
2426 break;
2427 case 'R':
2428 if (inclass) break;
2429 if (create) root = new LineEnding();
2430 return -1;
2431 case 'S':
2432 if (create) {
2433 predicate = has(UNICODE_CHARACTER_CLASS) ?
2434 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2435 predicate = predicate.negate();
2436 if (!inclass)
2437 root = newCharProperty(predicate);
2438 }
2439 return -1;
2440 case 'T':
2441 case 'U':
2442 break;
2443 case 'V':
2444 if (create) {
2445 predicate = VertWS().negate();
2446 if (!inclass)
2447 root = newCharProperty(predicate);
2448 }
2449 return -1;
2450 case 'W':
2451 if (create) {
2452 predicate = has(UNICODE_CHARACTER_CLASS) ?
2453 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2454 predicate = predicate.negate();
2455 if (!inclass)
2456 root = newCharProperty(predicate);
2457 }
2458 return -1;
2459 case 'X':
2460 if (inclass) break;
2461 if (create) {
2462 root = new XGrapheme();
2463 }
2464 return -1;
2465 case 'Y':
2466 break;
2467 case 'Z':
2468 if (inclass) break;
2469 if (create) {
2470 if (has(UNIX_LINES))
2471 root = new UnixDollar(false);
2472 else
2473 root = new Dollar(false);
2474 }
2475 return -1;
2476 case 'a':
2477 return '\007';
2478 case 'b':
2479 if (inclass) break;
2480 if (create) {
2481 if (peek() == '{') {
2482 if (skip() == 'g') {
2483 if (read() == '}') {
2484 root = new GraphemeBound();
2485 return -1;
2486 }
2487 break; // error missing trailing }
2488 }
2489 unread(); unread();
2490 }
2491 root = new Bound(Bound.BOTH, has(UNICODE_CHARACTER_CLASS));
2492 }
2493 return -1;
2494 case 'c':
2495 return c();
2496 case 'd':
2497 if (create) {
2498 predicate = has(UNICODE_CHARACTER_CLASS) ?
2499 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2500 if (!inclass)
2501 root = newCharProperty(predicate);
2502 }
2503 return -1;
2504 case 'e':
2505 return '\033';
2506 case 'f':
2507 return '\f';
2508 case 'g':
2509 break;
2510 case 'h':
2511 if (create) {
2512 predicate = HorizWS();
2513 if (!inclass)
2514 root = newCharProperty(predicate);
2515 }
2516 return -1;
2517 case 'i':
2518 case 'j':
2519 break;
2520 case 'k':
2521 if (inclass)
2522 break;
2523 if (read() != '<')
2524 throw error("\\k is not followed by '<' for named capturing group");
2525 String name = groupname(read());
2526 if (!namedGroups().containsKey(name))
2527 throw error("named capturing group <" + name + "> does not exist");
2528 if (create) {
2529 hasGroupRef = true;
2530 if (has(CASE_INSENSITIVE))
2531 root = new CIBackRef(namedGroups().get(name), has(UNICODE_CASE));
2532 else
2533 root = new BackRef(namedGroups().get(name));
2534 }
2535 return -1;
2536 case 'l':
2537 case 'm':
2538 break;
2539 case 'n':
2540 return '\n';
2541 case 'o':
2542 case 'p':
2543 case 'q':
2544 break;
2545 case 'r':
2546 return '\r';
2547 case 's':
2548 if (create) {
2549 predicate = has(UNICODE_CHARACTER_CLASS) ?
2550 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2551 if (!inclass)
2552 root = newCharProperty(predicate);
2553 }
2554 return -1;
2555 case 't':
2556 return '\t';
2557 case 'u':
2558 return u();
2559 case 'v':
2560 // '\v' was implemented as VT/0x0B in releases < 1.8 (though
2561 // undocumented). In JDK8 '\v' is specified as a predefined
2562 // character class for all vertical whitespace characters.
2563 // So [-1, root=VertWS node] pair is returned (instead of a
2564 // single 0x0B). This breaks the range if '\v' is used as
2565 // the start or end value, such as [\v-...] or [...-\v], in
2566 // which a single definite value (0x0B) is expected. For
2567 // compatibility concern '\013'/0x0B is returned if isrange.
2568 if (isrange)
2569 return '\013';
2570 if (create) {
2571 predicate = VertWS();
2572 if (!inclass)
2573 root = newCharProperty(predicate);
2574 }
2575 return -1;
2576 case 'w':
2577 if (create) {
2578 predicate = has(UNICODE_CHARACTER_CLASS) ?
2579 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2580 if (!inclass)
2581 root = newCharProperty(predicate);
2582 }
2583 return -1;
2584 case 'x':
2585 return x();
2586 case 'y':
2587 break;
2588 case 'z':
2589 if (inclass) break;
2590 if (create) root = new End();
2591 return -1;
2592 default:
2593 return ch;
2594 }
2595 throw error("Illegal/unsupported escape sequence");
2596 }
2597
2598 /**
2599 * Parse a character class, and return the node that matches it.
2600 *
2601 * Consumes a ] on the way out if consume is true. Usually consume
2602 * is true except for the case of [abc&&def] where def is a separate
2603 * right hand node with "understood" brackets.
2604 */
2605 private CharPredicate clazz(boolean consume) {
2606 CharPredicate prev = null;
2607 CharPredicate curr = null;
2608 BitClass bits = new BitClass();
2609 BmpCharPredicate bitsP = ch -> ch < 256 && bits.bits[ch];
2610
2611 boolean isNeg = false;
2612 boolean hasBits = false;
2613 int ch = next();
2614
2615 // Negates if first char in a class, otherwise literal
2616 if (ch == '^' && temp[cursor-1] == '[') {
2617 ch = next();
2618 isNeg = true;
2619 }
2620 for (;;) {
2621 switch (ch) {
2622 case '[':
2623 curr = clazz(true);
2624 if (prev == null)
2625 prev = curr;
2626 else
2627 prev = prev.union(curr);
2628 ch = peek();
2629 continue;
2630 case '&':
2631 ch = next();
2632 if (ch == '&') {
2633 ch = next();
2634 CharPredicate right = null;
2635 while (ch != ']' && ch != '&') {
2636 if (ch == '[') {
2637 if (right == null)
2638 right = clazz(true);
2639 else
2640 right = right.union(clazz(true));
2641 } else { // abc&&def
2642 unread();
2643 right = clazz(false);
2644 }
2645 ch = peek();
2646 }
2647 if (hasBits) {
2648 // bits used, union has high precedence
2649 if (prev == null) {
2650 prev = curr = bitsP;
2651 } else {
2652 prev = prev.union(bitsP);
2653 }
2654 hasBits = false;
2655 }
2656 if (right != null)
2657 curr = right;
2658 if (prev == null) {
2659 if (right == null)
2660 throw error("Bad class syntax");
2661 else
2662 prev = right;
2663 } else {
2664 prev = prev.and(curr);
2665 }
2666 } else {
2667 // treat as a literal &
2668 unread();
2669 break;
2670 }
2671 continue;
2672 case 0:
2673 if (cursor >= patternLength)
2674 throw error("Unclosed character class");
2675 break;
2676 case ']':
2677 if (prev != null || hasBits) {
2678 if (consume)
2679 next();
2680 if (prev == null)
2681 prev = bitsP;
2682 else if (hasBits)
2683 prev = prev.union(bitsP);
2684 if (isNeg)
2685 return prev.negate();
2686 return prev;
2687 }
2688 break;
2689 default:
2690 break;
2691 }
2692 curr = range(bits);
2693 if (curr == null) { // the bits used
2694 hasBits = true;
2695 } else {
2696 if (prev == null)
2697 prev = curr;
2698 else if (prev != curr)
2699 prev = prev.union(curr);
2700 }
2701 ch = peek();
2702 }
2703 }
2704
2705 private CharPredicate bitsOrSingle(BitClass bits, int ch) {
2706 /* Bits can only handle codepoints in [u+0000-u+00ff] range.
2707 Use "single" node instead of bits when dealing with unicode
2708 case folding for codepoints listed below.
2709 (1)Uppercase out of range: u+00ff, u+00b5
2710 toUpperCase(u+00ff) -> u+0178
2711 toUpperCase(u+00b5) -> u+039c
2712 (2)LatinSmallLetterLongS u+17f
2713 toUpperCase(u+017f) -> u+0053
2714 (3)LatinSmallLetterDotlessI u+131
2715 toUpperCase(u+0131) -> u+0049
2716 (4)LatinCapitalLetterIWithDotAbove u+0130
2717 toLowerCase(u+0130) -> u+0069
2718 (5)KelvinSign u+212a
2719 toLowerCase(u+212a) ==> u+006B
2720 (6)AngstromSign u+212b
2721 toLowerCase(u+212b) ==> u+00e5
2722 */
2723 if (ch < 256 &&
2724 !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) &&
2725 (ch == 0xff || ch == 0xb5 ||
2726 ch == 0x49 || ch == 0x69 || //I and i
2727 ch == 0x53 || ch == 0x73 || //S and s
2728 ch == 0x4b || ch == 0x6b || //K and k
2729 ch == 0xc5 || ch == 0xe5))) { //A+ring
2730 bits.add(ch, flags0);
2731 return null;
2732 }
2733 return single(ch);
2734 }
2735
2736 /**
2737 * Returns a suitably optimized, single character predicate
2738 */
2739 private CharPredicate single(final int ch) {
2740 if (has(CASE_INSENSITIVE)) {
2741 int lower, upper;
2742 if (has(UNICODE_CASE)) {
2743 upper = Character.toUpperCase(ch);
2744 lower = Character.toLowerCase(upper);
2745 // Unicode case insensitive matches
2746 if (upper != lower)
2747 return SingleU(lower);
2748 } else if (ASCII.isAscii(ch)) {
2749 lower = ASCII.toLower(ch);
2750 upper = ASCII.toUpper(ch);
2751 // Case insensitive matches a given BMP character
2752 if (lower != upper)
2753 return SingleI(lower, upper);
2754 }
2755 }
2756 if (isSupplementary(ch))
2757 return SingleS(ch);
2758 return Single(ch); // Match a given BMP character
2759 }
2760
2761 /**
2762 * Parse a single character or a character range in a character class
2763 * and return its representative node.
2764 */
2765 private CharPredicate range(BitClass bits) {
2766 int ch = peek();
2767 if (ch == '\\') {
2768 ch = nextEscaped();
2769 if (ch == 'p' || ch == 'P') { // A property
2770 boolean comp = (ch == 'P');
2771 boolean oneLetter = true;
2772 // Consume { if present
2773 ch = next();
2774 if (ch != '{')
2775 unread();
2776 else
2777 oneLetter = false;
2778 return family(oneLetter, comp);
2779 } else { // ordinary escape
2780 boolean isrange = temp[cursor+1] == '-';
2781 unread();
2782 ch = escape(true, true, isrange);
2783 if (ch == -1)
2784 return predicate;
2785 }
2786 } else {
2787 next();
2788 }
2789 if (ch >= 0) {
2790 if (peek() == '-') {
2791 int endRange = temp[cursor+1];
2792 if (endRange == '[') {
2793 return bitsOrSingle(bits, ch);
2794 }
2795 if (endRange != ']') {
2796 next();
2797 int m = peek();
2798 if (m == '\\') {
2799 m = escape(true, false, true);
2800 } else {
2801 next();
2802 }
2803 if (m < ch) {
2804 throw error("Illegal character range");
2805 }
2806 if (has(CASE_INSENSITIVE)) {
2807 if (has(UNICODE_CASE))
2808 return CIRangeU(ch, m);
2809 return CIRange(ch, m);
2810 } else {
2811 return Range(ch, m);
2812 }
2813 }
2814 }
2815 return bitsOrSingle(bits, ch);
2816 }
2817 throw error("Unexpected character '"+((char)ch)+"'");
2818 }
2819
2820 /**
2821 * Parses a Unicode character family and returns its representative node.
2822 */
2823 private CharPredicate family(boolean singleLetter, boolean isComplement) {
2824 next();
2825 String name;
2826 CharPredicate p = null;
2827
2828 if (singleLetter) {
2829 int c = temp[cursor];
2830 if (!Character.isSupplementaryCodePoint(c)) {
2831 name = String.valueOf((char)c);
2832 } else {
2833 name = new String(temp, cursor, 1);
2834 }
2835 read();
2836 } else {
2837 int i = cursor;
2838 mark('}');
2839 while(read() != '}') {
2840 }
2841 mark('\000');
2842 int j = cursor;
2843 if (j > patternLength)
2844 throw error("Unclosed character family");
2845 if (i + 1 >= j)
2846 throw error("Empty character family");
2847 name = new String(temp, i, j-i-1);
2848 }
2849
2850 int i = name.indexOf('=');
2851 if (i != -1) {
2852 // property construct \p{name=value}
2853 String value = name.substring(i + 1);
2854 name = name.substring(0, i).toLowerCase(Locale.ENGLISH);
2855 switch (name) {
2856 case "sc":
2857 case "script":
2858 p = CharPredicates.forUnicodeScript(value);
2859 break;
2860 case "blk":
2861 case "block":
2862 p = CharPredicates.forUnicodeBlock(value);
2863 break;
2864 case "gc":
2865 case "general_category":
2866 p = CharPredicates.forProperty(value);
2867 break;
2868 default:
2869 break;
2870 }
2871 if (p == null)
2872 throw error("Unknown Unicode property {name=<" + name + ">, "
2873 + "value=<" + value + ">}");
2874
2875 } else {
2876 if (name.startsWith("In")) {
2877 // \p{InBlockName}
2878 p = CharPredicates.forUnicodeBlock(name.substring(2));
2879 } else if (name.startsWith("Is")) {
2880 // \p{IsGeneralCategory} and \p{IsScriptName}
2881 name = name.substring(2);
2882 p = CharPredicates.forUnicodeProperty(name);
2883 if (p == null)
2884 p = CharPredicates.forProperty(name);
2885 if (p == null)
2886 p = CharPredicates.forUnicodeScript(name);
2887 } else {
2888 if (has(UNICODE_CHARACTER_CLASS)) {
2889 p = CharPredicates.forPOSIXName(name);
2890 }
2891 if (p == null)
2892 p = CharPredicates.forProperty(name);
2893 }
2894 if (p == null)
2895 throw error("Unknown character property name {In/Is" + name + "}");
2896 }
2897 if (isComplement) {
2898 // it might be too expensive to detect if a complement of
2899 // CharProperty can match "certain" supplementary. So just
2900 // go with StartS.
2901 hasSupplementary = true;
2902 p = p.negate();
2903 }
2904 return p;
2905 }
2906
2907 private CharProperty newCharProperty(CharPredicate p) {
2908 if (p == null)
2909 return null;
2910 if (p instanceof BmpCharPredicate)
2911 return new BmpCharProperty((BmpCharPredicate)p);
2912 else
2913 return new CharProperty(p);
2914 }
2915
2916 /**
2917 * Parses and returns the name of a "named capturing group", the trailing
2918 * ">" is consumed after parsing.
2919 */
2920 private String groupname(int ch) {
2921 StringBuilder sb = new StringBuilder();
2922 if (!ASCII.isAlpha(ch))
2923 throw error("capturing group name does not start with a Latin letter");
2924 do {
2925 sb.append((char) ch);
2926 } while (ASCII.isAlnum(ch=read()));
2927 if (ch != '>')
2928 throw error("named capturing group is missing trailing '>'");
2929 return sb.toString();
2930 }
2931
2932 /**
2933 * Parses a group and returns the head node of a set of nodes that process
2934 * the group. Sometimes a double return system is used where the tail is
2935 * returned in root.
2936 */
2937 private Node group0() {
2938 boolean capturingGroup = false;
2939 Node head = null;
2940 Node tail = null;
2941 int save = flags0;
2942 int saveTCNCount = topClosureNodes.size();
2943 root = null;
2944 int ch = next();
2945 if (ch == '?') {
2946 ch = skip();
2947 switch (ch) {
2948 case ':': // (?:xxx) pure group
2949 head = createGroup(true);
2950 tail = root;
2951 head.next = expr(tail);
2952 break;
2953 case '=': // (?=xxx) and (?!xxx) lookahead
2954 case '!':
2955 head = createGroup(true);
2956 tail = root;
2957 head.next = expr(tail);
2958 if (ch == '=') {
2959 head = tail = new Pos(head);
2960 } else {
2961 head = tail = new Neg(head);
2962 }
2963 break;
2964 case '>': // (?>xxx) independent group
2965 head = createGroup(true);
2966 tail = root;
2967 head.next = expr(tail);
2968 head = tail = new Ques(head, Qtype.INDEPENDENT);
2969 break;
2970 case '<': // (?<xxx) look behind
2971 ch = read();
2972 if (ch != '=' && ch != '!') {
2973 // named captured group
2974 String name = groupname(ch);
2975 if (namedGroups().containsKey(name))
2976 throw error("Named capturing group <" + name
2977 + "> is already defined");
2978 capturingGroup = true;
2979 head = createGroup(false);
2980 tail = root;
2981 namedGroups().put(name, capturingGroupCount-1);
2982 head.next = expr(tail);
2983 break;
2984 }
2985 int start = cursor;
2986 head = createGroup(true);
2987 tail = root;
2988 head.next = expr(tail);
2989 tail.next = lookbehindEnd;
2990 TreeInfo info = new TreeInfo();
2991 head.study(info);
2992 if (info.maxValid == false) {
2993 throw error("Look-behind group does not have "
2994 + "an obvious maximum length");
2995 }
2996 boolean hasSupplementary = findSupplementary(start, patternLength);
2997 if (ch == '=') {
2998 head = tail = (hasSupplementary ?
2999 new BehindS(head, info.maxLength,
3000 info.minLength) :
3001 new Behind(head, info.maxLength,
3002 info.minLength));
3003 } else { // if (ch == '!')
3004 head = tail = (hasSupplementary ?
3005 new NotBehindS(head, info.maxLength,
3006 info.minLength) :
3007 new NotBehind(head, info.maxLength,
3008 info.minLength));
3009 }
3010 // clear all top-closure-nodes inside lookbehind
3011 if (saveTCNCount < topClosureNodes.size())
3012 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3013 break;
3014 case '$':
3015 case '@':
3016 throw error("Unknown group type");
3017 default: // (?xxx:) inlined match flags
3018 unread();
3019 addFlag();
3020 ch = read();
3021 if (ch == ')') {
3022 return null; // Inline modifier only
3023 }
3024 if (ch != ':') {
3025 throw error("Unknown inline modifier");
3026 }
3027 head = createGroup(true);
3028 tail = root;
3029 head.next = expr(tail);
3030 break;
3031 }
3032 } else { // (xxx) a regular group
3033 capturingGroup = true;
3034 head = createGroup(false);
3035 tail = root;
3036 head.next = expr(tail);
3037 }
3038
3039 accept(')', "Unclosed group");
3040 flags0 = save;
3041
3042 // Check for quantifiers
3043 Node node = closure(head);
3044 if (node == head) { // No closure
3045 root = tail;
3046 return node; // Dual return
3047 }
3048 if (head == tail) { // Zero length assertion
3049 root = node;
3050 return node; // Dual return
3051 }
3052
3053 // have group closure, clear all inner closure nodes from the
3054 // top list (no backtracking stopper optimization for inner
3055 if (saveTCNCount < topClosureNodes.size())
3056 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3057
3058 if (node instanceof Ques) {
3059 Ques ques = (Ques) node;
3060 if (ques.type == Qtype.POSSESSIVE) {
3061 root = node;
3062 return node;
3063 }
3064 tail.next = new BranchConn();
3065 tail = tail.next;
3066 if (ques.type == Qtype.GREEDY) {
3067 head = new Branch(head, null, tail);
3068 } else { // Reluctant quantifier
3069 head = new Branch(null, head, tail);
3070 }
3071 root = tail;
3072 return head;
3073 } else if (node instanceof Curly) {
3074 Curly curly = (Curly) node;
3075 if (curly.type == Qtype.POSSESSIVE) {
3076 root = node;
3077 return node;
3078 }
3079 // Discover if the group is deterministic
3080 TreeInfo info = new TreeInfo();
3081 if (head.study(info)) { // Deterministic
3082 GroupTail temp = (GroupTail) tail;
3083 head = root = new GroupCurly(head.next, curly.cmin,
3084 curly.cmax, curly.type,
3085 ((GroupTail)tail).localIndex,
3086 ((GroupTail)tail).groupIndex,
3087 capturingGroup);
3088 return head;
3089 } else { // Non-deterministic
3090 int temp = ((GroupHead) head).localIndex;
3091 Loop loop;
3092 if (curly.type == Qtype.GREEDY) {
3093 loop = new Loop(this.localCount, temp);
3094 // add the max_reps greedy to the top-closure-node list
3095 if (curly.cmax == MAX_REPS)
3096 topClosureNodes.add(loop);
3097 } else { // Reluctant Curly
3098 loop = new LazyLoop(this.localCount, temp);
3099 }
3100 Prolog prolog = new Prolog(loop);
3101 this.localCount += 1;
3102 loop.cmin = curly.cmin;
3103 loop.cmax = curly.cmax;
3104 loop.body = head;
3105 tail.next = loop;
3106 root = loop;
3107 return prolog; // Dual return
3108 }
3109 }
3110 throw error("Internal logic error");
3111 }
3112
3113 /**
3114 * Create group head and tail nodes using double return. If the group is
3115 * created with anonymous true then it is a pure group and should not
3116 * affect group counting.
3117 */
3118 private Node createGroup(boolean anonymous) {
3119 int localIndex = localCount++;
3120 int groupIndex = 0;
3121 if (!anonymous)
3122 groupIndex = capturingGroupCount++;
3123 GroupHead head = new GroupHead(localIndex);
3124 root = new GroupTail(localIndex, groupIndex);
3125
3126 // for debug/print only, head.match does NOT need the "tail" info
3127 head.tail = (GroupTail)root;
3128
3129 if (!anonymous && groupIndex < 10)
3130 groupNodes[groupIndex] = head;
3131 return head;
3132 }
3133
3134 @SuppressWarnings("fallthrough")
3135 /**
3136 * Parses inlined match flags and set them appropriately.
3137 */
3138 private void addFlag() {
3139 int ch = peek();
3140 for (;;) {
3141 switch (ch) {
3142 case 'i':
3143 flags0 |= CASE_INSENSITIVE;
3144 break;
3145 case 'm':
3146 flags0 |= MULTILINE;
3147 break;
3148 case 's':
3149 flags0 |= DOTALL;
3150 break;
3151 case 'd':
3152 flags0 |= UNIX_LINES;
3153 break;
3154 case 'u':
3155 flags0 |= UNICODE_CASE;
3156 break;
3157 case 'c':
3158 flags0 |= CANON_EQ;
3159 break;
3160 case 'x':
3161 flags0 |= COMMENTS;
3162 break;
3163 case 'U':
3164 flags0 |= (UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3165 break;
3166 case '-': // subFlag then fall through
3167 ch = next();
3168 subFlag();
3169 default:
3170 return;
3171 }
3172 ch = next();
3173 }
3174 }
3175
3176 @SuppressWarnings("fallthrough")
3177 /**
3178 * Parses the second part of inlined match flags and turns off
3179 * flags appropriately.
3180 */
3181 private void subFlag() {
3182 int ch = peek();
3183 for (;;) {
3184 switch (ch) {
3185 case 'i':
3186 flags0 &= ~CASE_INSENSITIVE;
3187 break;
3188 case 'm':
3189 flags0 &= ~MULTILINE;
3190 break;
3191 case 's':
3192 flags0 &= ~DOTALL;
3193 break;
3194 case 'd':
3195 flags0 &= ~UNIX_LINES;
3196 break;
3197 case 'u':
3198 flags0 &= ~UNICODE_CASE;
3199 break;
3200 case 'c':
3201 flags0 &= ~CANON_EQ;
3202 break;
3203 case 'x':
3204 flags0 &= ~COMMENTS;
3205 break;
3206 case 'U':
3207 flags0 &= ~(UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3208 break;
3209 default:
3210 return;
3211 }
3212 ch = next();
3213 }
3214 }
3215
3216 static final int MAX_REPS = 0x7FFFFFFF;
3217
3218 static enum Qtype {
3219 GREEDY, LAZY, POSSESSIVE, INDEPENDENT
3220 }
3221
3222 private Node curly(Node prev, int cmin) {
3223 int ch = next();
3224 if (ch == '?') {
3225 next();
3226 return new Curly(prev, cmin, MAX_REPS, Qtype.LAZY);
3227 } else if (ch == '+') {
3228 next();
3229 return new Curly(prev, cmin, MAX_REPS, Qtype.POSSESSIVE);
3230 }
3231 if (prev instanceof BmpCharProperty) {
3232 return new BmpCharPropertyGreedy((BmpCharProperty)prev, cmin);
3233 } else if (prev instanceof CharProperty) {
3234 return new CharPropertyGreedy((CharProperty)prev, cmin);
3235 }
3236 return new Curly(prev, cmin, MAX_REPS, Qtype.GREEDY);
3237 }
3238
3239 /**
3240 * Processes repetition. If the next character peeked is a quantifier
3241 * then new nodes must be appended to handle the repetition.
3242 * Prev could be a single or a group, so it could be a chain of nodes.
3243 */
3244 private Node closure(Node prev) {
3245 Node atom;
3246 int ch = peek();
3247 switch (ch) {
3248 case '?':
3249 ch = next();
3250 if (ch == '?') {
3251 next();
3252 return new Ques(prev, Qtype.LAZY);
3253 } else if (ch == '+') {
3254 next();
3255 return new Ques(prev, Qtype.POSSESSIVE);
3256 }
3257 return new Ques(prev, Qtype.GREEDY);
3258 case '*':
3259 return curly(prev, 0);
3260 case '+':
3261 return curly(prev, 1);
3262 case '{':
3263 ch = temp[cursor+1];
3264 if (ASCII.isDigit(ch)) {
3265 skip();
3266 int cmin = 0;
3267 do {
3268 cmin = cmin * 10 + (ch - '0');
3269 } while (ASCII.isDigit(ch = read()));
3270 int cmax = cmin;
3271 if (ch == ',') {
3272 ch = read();
3273 cmax = MAX_REPS;
3274 if (ch != '}') {
3275 cmax = 0;
3276 while (ASCII.isDigit(ch)) {
3277 cmax = cmax * 10 + (ch - '0');
3278 ch = read();
3279 }
3280 }
3281 }
3282 if (ch != '}')
3283 throw error("Unclosed counted closure");
3284 if (((cmin) | (cmax) | (cmax - cmin)) < 0)
3285 throw error("Illegal repetition range");
3286 Curly curly;
3287 ch = peek();
3288 if (ch == '?') {
3289 next();
3290 curly = new Curly(prev, cmin, cmax, Qtype.LAZY);
3291 } else if (ch == '+') {
3292 next();
3293 curly = new Curly(prev, cmin, cmax, Qtype.POSSESSIVE);
3294 } else {
3295 curly = new Curly(prev, cmin, cmax, Qtype.GREEDY);
3296 }
3297 return curly;
3298 } else {
3299 throw error("Illegal repetition");
3300 }
3301 default:
3302 return prev;
3303 }
3304 }
3305
3306 /**
3307 * Utility method for parsing control escape sequences.
3308 */
3309 private int c() {
3310 if (cursor < patternLength) {
3311 return read() ^ 64;
3312 }
3313 throw error("Illegal control escape sequence");
3314 }
3315
3316 /**
3317 * Utility method for parsing octal escape sequences.
3318 */
3319 private int o() {
3320 int n = read();
3321 if (((n-'0')|('7'-n)) >= 0) {
3322 int m = read();
3323 if (((m-'0')|('7'-m)) >= 0) {
3324 int o = read();
3325 if ((((o-'0')|('7'-o)) >= 0) && (((n-'0')|('3'-n)) >= 0)) {
3326 return (n - '0') * 64 + (m - '0') * 8 + (o - '0');
3327 }
3328 unread();
3329 return (n - '0') * 8 + (m - '0');
3330 }
3331 unread();
3332 return (n - '0');
3333 }
3334 throw error("Illegal octal escape sequence");
3335 }
3336
3337 /**
3338 * Utility method for parsing hexadecimal escape sequences.
3339 */
3340 private int x() {
3341 int n = read();
3342 if (ASCII.isHexDigit(n)) {
3343 int m = read();
3344 if (ASCII.isHexDigit(m)) {
3345 return ASCII.toDigit(n) * 16 + ASCII.toDigit(m);
3346 }
3347 } else if (n == '{' && ASCII.isHexDigit(peek())) {
3348 int ch = 0;
3349 while (ASCII.isHexDigit(n = read())) {
3350 ch = (ch << 4) + ASCII.toDigit(n);
3351 if (ch > Character.MAX_CODE_POINT)
3352 throw error("Hexadecimal codepoint is too big");
3353 }
3354 if (n != '}')
3355 throw error("Unclosed hexadecimal escape sequence");
3356 return ch;
3357 }
3358 throw error("Illegal hexadecimal escape sequence");
3359 }
3360
3361 /**
3362 * Utility method for parsing unicode escape sequences.
3363 */
3364 private int cursor() {
3365 return cursor;
3366 }
3367
3368 private void setcursor(int pos) {
3369 cursor = pos;
3370 }
3371
3372 private int uxxxx() {
3373 int n = 0;
3374 for (int i = 0; i < 4; i++) {
3375 int ch = read();
3376 if (!ASCII.isHexDigit(ch)) {
3377 throw error("Illegal Unicode escape sequence");
3378 }
3379 n = n * 16 + ASCII.toDigit(ch);
3380 }
3381 return n;
3382 }
3383
3384 private int u() {
3385 int n = uxxxx();
3386 if (Character.isHighSurrogate((char)n)) {
3387 int cur = cursor();
3388 if (read() == '\\' && read() == 'u') {
3389 int n2 = uxxxx();
3390 if (Character.isLowSurrogate((char)n2))
3391 return Character.toCodePoint((char)n, (char)n2);
3392 }
3393 setcursor(cur);
3394 }
3395 return n;
3396 }
3397
3398 private int N() {
3399 if (read() == '{') {
3400 int i = cursor;
3401 while (cursor < patternLength && read() != '}') {}
3402 if (cursor > patternLength)
3403 throw error("Unclosed character name escape sequence");
3404 String name = new String(temp, i, cursor - i - 1);
3405 try {
3406 return Character.codePointOf(name);
3407 } catch (IllegalArgumentException x) {
3408 throw error("Unknown character name [" + name + "]");
3409 }
3410 }
3411 throw error("Illegal character name escape sequence");
3412 }
3413
3414 //
3415 // Utility methods for code point support
3416 //
3417 private static final int countChars(CharSequence seq, int index,
3418 int lengthInCodePoints) {
3419 // optimization
3420 if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) {
3421 assert (index >= 0 && index < seq.length());
3422 return 1;
3423 }
3424 int length = seq.length();
3425 int x = index;
3426 if (lengthInCodePoints >= 0) {
3427 assert (index >= 0 && index < length);
3428 for (int i = 0; x < length && i < lengthInCodePoints; i++) {
3429 if (Character.isHighSurrogate(seq.charAt(x++))) {
3430 if (x < length && Character.isLowSurrogate(seq.charAt(x))) {
3431 x++;
3432 }
3433 }
3434 }
3435 return x - index;
3436 }
3437
3438 assert (index >= 0 && index <= length);
3439 if (index == 0) {
3440 return 0;
3441 }
3442 int len = -lengthInCodePoints;
3443 for (int i = 0; x > 0 && i < len; i++) {
3444 if (Character.isLowSurrogate(seq.charAt(--x))) {
3445 if (x > 0 && Character.isHighSurrogate(seq.charAt(x-1))) {
3446 x--;
3447 }
3448 }
3449 }
3450 return index - x;
3451 }
3452
3453 private static final int countCodePoints(CharSequence seq) {
3454 int length = seq.length();
3455 int n = 0;
3456 for (int i = 0; i < length; ) {
3457 n++;
3458 if (Character.isHighSurrogate(seq.charAt(i++))) {
3459 if (i < length && Character.isLowSurrogate(seq.charAt(i))) {
3460 i++;
3461 }
3462 }
3463 }
3464 return n;
3465 }
3466
3467 /**
3468 * Creates a bit vector for matching Latin-1 values. A normal BitClass
3469 * never matches values above Latin-1, and a complemented BitClass always
3470 * matches values above Latin-1.
3471 */
3472 static final class BitClass extends BmpCharProperty {
3473 final boolean[] bits;
3474 BitClass() {
3475 this(new boolean[256]);
3476 }
3477 private BitClass(boolean[] bits) {
3478 super( ch -> ch < 256 && bits[ch]);
3479 this.bits = bits;
3480 }
3481 BitClass add(int c, int flags) {
3482 assert c >= 0 && c <= 255;
3483 if ((flags & CASE_INSENSITIVE) != 0) {
3484 if (ASCII.isAscii(c)) {
3485 bits[ASCII.toUpper(c)] = true;
3486 bits[ASCII.toLower(c)] = true;
3487 } else if ((flags & UNICODE_CASE) != 0) {
3488 bits[Character.toLowerCase(c)] = true;
3489 bits[Character.toUpperCase(c)] = true;
3490 }
3491 }
3492 bits[c] = true;
3493 return this;
3494 }
3495 }
3496
3497 /**
3498 * Utility method for creating a string slice matcher.
3499 */
3500 private Node newSlice(int[] buf, int count, boolean hasSupplementary) {
3501 int[] tmp = new int[count];
3502 if (has(CASE_INSENSITIVE)) {
3503 if (has(UNICODE_CASE)) {
3504 for (int i = 0; i < count; i++) {
3505 tmp[i] = Character.toLowerCase(
3506 Character.toUpperCase(buf[i]));
3507 }
3508 return hasSupplementary? new SliceUS(tmp) : new SliceU(tmp);
3509 }
3510 for (int i = 0; i < count; i++) {
3511 tmp[i] = ASCII.toLower(buf[i]);
3512 }
3513 return hasSupplementary? new SliceIS(tmp) : new SliceI(tmp);
3514 }
3515 for (int i = 0; i < count; i++) {
3516 tmp[i] = buf[i];
3517 }
3518 return hasSupplementary ? new SliceS(tmp) : new Slice(tmp);
3519 }
3520
3521 /**
3522 * The following classes are the building components of the object
3523 * tree that represents a compiled regular expression. The object tree
3524 * is made of individual elements that handle constructs in the Pattern.
3525 * Each type of object knows how to match its equivalent construct with
3526 * the match() method.
3527 */
3528
3529 /**
3530 * Base class for all node classes. Subclasses should override the match()
3531 * method as appropriate. This class is an accepting node, so its match()
3532 * always returns true.
3533 */
3534 static class Node extends Object {
3535 Node next;
3536 Node() {
3537 next = Pattern.accept;
3538 }
3539 /**
3540 * This method implements the classic accept node.
3541 */
3542 boolean match(Matcher matcher, int i, CharSequence seq) {
3543 matcher.last = i;
3544 matcher.groups[0] = matcher.first;
3545 matcher.groups[1] = matcher.last;
3546 return true;
3547 }
3548 /**
3549 * This method is good for all zero length assertions.
3550 */
3551 boolean study(TreeInfo info) {
3552 if (next != null) {
3553 return next.study(info);
3554 } else {
3555 return info.deterministic;
3556 }
3557 }
3558 }
3559
3560 static class LastNode extends Node {
3561 /**
3562 * This method implements the classic accept node with
3563 * the addition of a check to see if the match occurred
3564 * using all of the input.
3565 */
3566 boolean match(Matcher matcher, int i, CharSequence seq) {
3567 if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to)
3568 return false;
3569 matcher.last = i;
3570 matcher.groups[0] = matcher.first;
3571 matcher.groups[1] = matcher.last;
3572 return true;
3573 }
3574 }
3575
3576 /**
3577 * Used for REs that can start anywhere within the input string.
3578 * This basically tries to match repeatedly at each spot in the
3579 * input string, moving forward after each try. An anchored search
3580 * or a BnM will bypass this node completely.
3581 */
3582 static class Start extends Node {
3583 int minLength;
3584 Start(Node node) {
3585 this.next = node;
3586 TreeInfo info = new TreeInfo();
3587 next.study(info);
3588 minLength = info.minLength;
3589 }
3590 boolean match(Matcher matcher, int i, CharSequence seq) {
3591 if (i > matcher.to - minLength) {
3592 matcher.hitEnd = true;
3593 return false;
3594 }
3595 int guard = matcher.to - minLength;
3596 for (; i <= guard; i++) {
3597 if (next.match(matcher, i, seq)) {
3598 matcher.first = i;
3599 matcher.groups[0] = matcher.first;
3600 matcher.groups[1] = matcher.last;
3601 return true;
3602 }
3603 }
3604 matcher.hitEnd = true;
3605 return false;
3606 }
3607 boolean study(TreeInfo info) {
3608 next.study(info);
3609 info.maxValid = false;
3610 info.deterministic = false;
3611 return false;
3612 }
3613 }
3614
3615 /*
3616 * StartS supports supplementary characters, including unpaired surrogates.
3617 */
3618 static final class StartS extends Start {
3619 StartS(Node node) {
3620 super(node);
3621 }
3622 boolean match(Matcher matcher, int i, CharSequence seq) {
3623 if (i > matcher.to - minLength) {
3624 matcher.hitEnd = true;
3625 return false;
3626 }
3627 int guard = matcher.to - minLength;
3628 while (i <= guard) {
3629 //if ((ret = next.match(matcher, i, seq)) || i == guard)
3630 if (next.match(matcher, i, seq)) {
3631 matcher.first = i;
3632 matcher.groups[0] = matcher.first;
3633 matcher.groups[1] = matcher.last;
3634 return true;
3635 }
3636 if (i == guard)
3637 break;
3638 // Optimization to move to the next character. This is
3639 // faster than countChars(seq, i, 1).
3640 if (Character.isHighSurrogate(seq.charAt(i++))) {
3641 if (i < seq.length() &&
3642 Character.isLowSurrogate(seq.charAt(i))) {
3643 i++;
3644 }
3645 }
3646 }
3647 matcher.hitEnd = true;
3648 return false;
3649 }
3650 }
3651
3652 /**
3653 * Node to anchor at the beginning of input. This object implements the
3654 * match for a \A sequence, and the caret anchor will use this if not in
3655 * multiline mode.
3656 */
3657 static final class Begin extends Node {
3658 boolean match(Matcher matcher, int i, CharSequence seq) {
3659 int fromIndex = (matcher.anchoringBounds) ?
3660 matcher.from : 0;
3661 if (i == fromIndex && next.match(matcher, i, seq)) {
3662 matcher.first = i;
3663 matcher.groups[0] = i;
3664 matcher.groups[1] = matcher.last;
3665 return true;
3666 } else {
3667 return false;
3668 }
3669 }
3670 }
3671
3672 /**
3673 * Node to anchor at the end of input. This is the absolute end, so this
3674 * should not match at the last newline before the end as $ will.
3675 */
3676 static final class End extends Node {
3677 boolean match(Matcher matcher, int i, CharSequence seq) {
3678 int endIndex = (matcher.anchoringBounds) ?
3679 matcher.to : matcher.getTextLength();
3680 if (i == endIndex) {
3681 matcher.hitEnd = true;
3682 return next.match(matcher, i, seq);
3683 }
3684 return false;
3685 }
3686 }
3687
3688 /**
3689 * Node to anchor at the beginning of a line. This is essentially the
3690 * object to match for the multiline ^.
3691 */
3692 static final class Caret extends Node {
3693 boolean match(Matcher matcher, int i, CharSequence seq) {
3694 int startIndex = matcher.from;
3695 int endIndex = matcher.to;
3696 if (!matcher.anchoringBounds) {
3697 startIndex = 0;
3698 endIndex = matcher.getTextLength();
3699 }
3700 // Perl does not match ^ at end of input even after newline
3701 if (i == endIndex) {
3702 matcher.hitEnd = true;
3703 return false;
3704 }
3705 if (i > startIndex) {
3706 char ch = seq.charAt(i-1);
3707 if (ch != '\n' && ch != '\r'
3708 && (ch|1) != '\u2029'
3709 && ch != '\u0085' ) {
3710 return false;
3711 }
3712 // Should treat /r/n as one newline
3713 if (ch == '\r' && seq.charAt(i) == '\n')
3714 return false;
3715 }
3716 return next.match(matcher, i, seq);
3717 }
3718 }
3719
3720 /**
3721 * Node to anchor at the beginning of a line when in unixdot mode.
3722 */
3723 static final class UnixCaret extends Node {
3724 boolean match(Matcher matcher, int i, CharSequence seq) {
3725 int startIndex = matcher.from;
3726 int endIndex = matcher.to;
3727 if (!matcher.anchoringBounds) {
3728 startIndex = 0;
3729 endIndex = matcher.getTextLength();
3730 }
3731 // Perl does not match ^ at end of input even after newline
3732 if (i == endIndex) {
3733 matcher.hitEnd = true;
3734 return false;
3735 }
3736 if (i > startIndex) {
3737 char ch = seq.charAt(i-1);
3738 if (ch != '\n') {
3739 return false;
3740 }
3741 }
3742 return next.match(matcher, i, seq);
3743 }
3744 }
3745
3746 /**
3747 * Node to match the location where the last match ended.
3748 * This is used for the \G construct.
3749 */
3750 static final class LastMatch extends Node {
3751 boolean match(Matcher matcher, int i, CharSequence seq) {
3752 if (i != matcher.oldLast)
3753 return false;
3754 return next.match(matcher, i, seq);
3755 }
3756 }
3757
3758 /**
3759 * Node to anchor at the end of a line or the end of input based on the
3760 * multiline mode.
3761 *
3762 * When not in multiline mode, the $ can only match at the very end
3763 * of the input, unless the input ends in a line terminator in which
3764 * it matches right before the last line terminator.
3765 *
3766 * Note that \r\n is considered an atomic line terminator.
3767 *
3768 * Like ^ the $ operator matches at a position, it does not match the
3769 * line terminators themselves.
3770 */
3771 static final class Dollar extends Node {
3772 boolean multiline;
3773 Dollar(boolean mul) {
3774 multiline = mul;
3775 }
3776 boolean match(Matcher matcher, int i, CharSequence seq) {
3777 int endIndex = (matcher.anchoringBounds) ?
3778 matcher.to : matcher.getTextLength();
3779 if (!multiline) {
3780 if (i < endIndex - 2)
3781 return false;
3782 if (i == endIndex - 2) {
3783 char ch = seq.charAt(i);
3784 if (ch != '\r')
3785 return false;
3786 ch = seq.charAt(i + 1);
3787 if (ch != '\n')
3788 return false;
3789 }
3790 }
3791 // Matches before any line terminator; also matches at the
3792 // end of input
3793 // Before line terminator:
3794 // If multiline, we match here no matter what
3795 // If not multiline, fall through so that the end
3796 // is marked as hit; this must be a /r/n or a /n
3797 // at the very end so the end was hit; more input
3798 // could make this not match here
3799 if (i < endIndex) {
3800 char ch = seq.charAt(i);
3801 if (ch == '\n') {
3802 // No match between \r\n
3803 if (i > 0 && seq.charAt(i-1) == '\r')
3804 return false;
3805 if (multiline)
3806 return next.match(matcher, i, seq);
3807 } else if (ch == '\r' || ch == '\u0085' ||
3808 (ch|1) == '\u2029') {
3809 if (multiline)
3810 return next.match(matcher, i, seq);
3811 } else { // No line terminator, no match
3812 return false;
3813 }
3814 }
3815 // Matched at current end so hit end
3816 matcher.hitEnd = true;
3817 // If a $ matches because of end of input, then more input
3818 // could cause it to fail!
3819 matcher.requireEnd = true;
3820 return next.match(matcher, i, seq);
3821 }
3822 boolean study(TreeInfo info) {
3823 next.study(info);
3824 return info.deterministic;
3825 }
3826 }
3827
3828 /**
3829 * Node to anchor at the end of a line or the end of input based on the
3830 * multiline mode when in unix lines mode.
3831 */
3832 static final class UnixDollar extends Node {
3833 boolean multiline;
3834 UnixDollar(boolean mul) {
3835 multiline = mul;
3836 }
3837 boolean match(Matcher matcher, int i, CharSequence seq) {
3838 int endIndex = (matcher.anchoringBounds) ?
3839 matcher.to : matcher.getTextLength();
3840 if (i < endIndex) {
3841 char ch = seq.charAt(i);
3842 if (ch == '\n') {
3843 // If not multiline, then only possible to
3844 // match at very end or one before end
3845 if (multiline == false && i != endIndex - 1)
3846 return false;
3847 // If multiline return next.match without setting
3848 // matcher.hitEnd
3849 if (multiline)
3850 return next.match(matcher, i, seq);
3851 } else {
3852 return false;
3853 }
3854 }
3855 // Matching because at the end or 1 before the end;
3856 // more input could change this so set hitEnd
3857 matcher.hitEnd = true;
3858 // If a $ matches because of end of input, then more input
3859 // could cause it to fail!
3860 matcher.requireEnd = true;
3861 return next.match(matcher, i, seq);
3862 }
3863 boolean study(TreeInfo info) {
3864 next.study(info);
3865 return info.deterministic;
3866 }
3867 }
3868
3869 /**
3870 * Node class that matches a Unicode line ending '\R'
3871 */
3872 static final class LineEnding extends Node {
3873 boolean match(Matcher matcher, int i, CharSequence seq) {
3874 // (u+000Du+000A|[u+000Au+000Bu+000Cu+000Du+0085u+2028u+2029])
3875 if (i < matcher.to) {
3876 int ch = seq.charAt(i);
3877 if (ch == 0x0A || ch == 0x0B || ch == 0x0C ||
3878 ch == 0x85 || ch == 0x2028 || ch == 0x2029)
3879 return next.match(matcher, i + 1, seq);
3880 if (ch == 0x0D) {
3881 i++;
3882 if (i < matcher.to) {
3883 if (seq.charAt(i) == 0x0A &&
3884 next.match(matcher, i + 1, seq)) {
3885 return true;
3886 }
3887 } else {
3888 matcher.hitEnd = true;
3889 }
3890 return next.match(matcher, i, seq);
3891 }
3892 } else {
3893 matcher.hitEnd = true;
3894 }
3895 return false;
3896 }
3897 boolean study(TreeInfo info) {
3898 info.minLength++;
3899 info.maxLength += 2;
3900 return next.study(info);
3901 }
3902 }
3903
3904 /**
3905 * Abstract node class to match one character satisfying some
3906 * boolean property.
3907 */
3908 static class CharProperty extends Node {
3909 CharPredicate predicate;
3910
3911 CharProperty (CharPredicate predicate) {
3912 this.predicate = predicate;
3913 }
3914 boolean match(Matcher matcher, int i, CharSequence seq) {
3915 if (i < matcher.to) {
3916 int ch = Character.codePointAt(seq, i);
3917 return predicate.is(ch) &&
3918 next.match(matcher, i + Character.charCount(ch), seq);
3919 } else {
3920 matcher.hitEnd = true;
3921 return false;
3922 }
3923 }
3924 boolean study(TreeInfo info) {
3925 info.minLength++;
3926 info.maxLength++;
3927 return next.study(info);
3928 }
3929 }
3930
3931 /**
3932 * Optimized version of CharProperty that works only for
3933 * properties never satisfied by Supplementary characters.
3934 */
3935 private static class BmpCharProperty extends CharProperty {
3936 BmpCharProperty (BmpCharPredicate predicate) {
3937 super(predicate);
3938 }
3939 boolean match(Matcher matcher, int i, CharSequence seq) {
3940 if (i < matcher.to) {
3941 return predicate.is(seq.charAt(i)) &&
3942 next.match(matcher, i + 1, seq);
3943 } else {
3944 matcher.hitEnd = true;
3945 return false;
3946 }
3947 }
3948 }
3949
3950 private static class NFCCharProperty extends Node {
3951 CharPredicate predicate;
3952 NFCCharProperty (CharPredicate predicate) {
3953 this.predicate = predicate;
3954 }
3955
3956 boolean match(Matcher matcher, int i, CharSequence seq) {
3957 if (i < matcher.to) {
3958 int ch0 = Character.codePointAt(seq, i);
3959 int n = Character.charCount(ch0);
3960 int j = i + n;
3961 while (j < matcher.to) {
3962 int ch1 = Character.codePointAt(seq, j);
3963 if (Grapheme.isBoundary(ch0, ch1))
3964 break;
3965 ch0 = ch1;
3966 j += Character.charCount(ch1);
3967 }
3968 if (i + n == j) { // single, assume nfc cp
3969 if (predicate.is(ch0))
3970 return next.match(matcher, j, seq);
3971 } else {
3972 while (i + n < j) {
3973 String nfc = Normalizer.normalize(
3974 seq.toString().substring(i, j), Normalizer.Form.NFC);
3975 if (nfc.codePointCount(0, nfc.length()) == 1) {
3976 if (predicate.is(nfc.codePointAt(0)) &&
3977 next.match(matcher, j, seq)) {
3978 return true;
3979 }
3980 }
3981
3982 ch0 = Character.codePointBefore(seq, j);
3983 j -= Character.charCount(ch0);
3984 }
3985 }
3986 if (j < matcher.to)
3987 return false;
3988 }
3989 matcher.hitEnd = true;
3990 return false;
3991 }
3992
3993 boolean study(TreeInfo info) {
3994 info.minLength++;
3995 info.deterministic = false;
3996 return next.study(info);
3997 }
3998 }
3999
4000 /**
4001 * Node class that matches an unicode extended grapheme cluster
4002 */
4003 static class XGrapheme extends Node {
4004 boolean match(Matcher matcher, int i, CharSequence seq) {
4005 if (i < matcher.to) {
4006 int ch0 = Character.codePointAt(seq, i);
4007 i += Character.charCount(ch0);
4008 while (i < matcher.to) {
4009 int ch1 = Character.codePointAt(seq, i);
4010 if (Grapheme.isBoundary(ch0, ch1))
4011 break;
4012 ch0 = ch1;
4013 i += Character.charCount(ch1);
4014 }
4015 return next.match(matcher, i, seq);
4016 }
4017 matcher.hitEnd = true;
4018 return false;
4019 }
4020
4021 boolean study(TreeInfo info) {
4022 info.minLength++;
4023 info.deterministic = false;
4024 return next.study(info);
4025 }
4026 }
4027
4028 /**
4029 * Node class that handles grapheme boundaries
4030 */
4031 static class GraphemeBound extends Node {
4032 boolean match(Matcher matcher, int i, CharSequence seq) {
4033 int startIndex = matcher.from;
4034 int endIndex = matcher.to;
4035 if (matcher.transparentBounds) {
4036 startIndex = 0;
4037 endIndex = matcher.getTextLength();
4038 }
4039 if (i == startIndex) {
4040 return next.match(matcher, i, seq);
4041 }
4042 if (i < endIndex) {
4043 if (Character.isSurrogatePair(seq.charAt(i-1), seq.charAt(i)) ||
4044 !Grapheme.isBoundary(Character.codePointBefore(seq, i),
4045 Character.codePointAt(seq, i))) {
4046 return false;
4047 }
4048 } else {
4049 matcher.hitEnd = true;
4050 matcher.requireEnd = true;
4051 }
4052 return next.match(matcher, i, seq);
4053 }
4054 }
4055
4056 /**
4057 * Base class for all Slice nodes
4058 */
4059 static class SliceNode extends Node {
4060 int[] buffer;
4061 SliceNode(int[] buf) {
4062 buffer = buf;
4063 }
4064 boolean study(TreeInfo info) {
4065 info.minLength += buffer.length;
4066 info.maxLength += buffer.length;
4067 return next.study(info);
4068 }
4069 }
4070
4071 /**
4072 * Node class for a case sensitive/BMP-only sequence of literal
4073 * characters.
4074 */
4075 static class Slice extends SliceNode {
4076 Slice(int[] buf) {
4077 super(buf);
4078 }
4079 boolean match(Matcher matcher, int i, CharSequence seq) {
4080 int[] buf = buffer;
4081 int len = buf.length;
4082 for (int j=0; j<len; j++) {
4083 if ((i+j) >= matcher.to) {
4084 matcher.hitEnd = true;
4085 return false;
4086 }
4087 if (buf[j] != seq.charAt(i+j))
4088 return false;
4089 }
4090 return next.match(matcher, i+len, seq);
4091 }
4092 }
4093
4094 /**
4095 * Node class for a case_insensitive/BMP-only sequence of literal
4096 * characters.
4097 */
4098 static class SliceI extends SliceNode {
4099 SliceI(int[] buf) {
4100 super(buf);
4101 }
4102 boolean match(Matcher matcher, int i, CharSequence seq) {
4103 int[] buf = buffer;
4104 int len = buf.length;
4105 for (int j=0; j<len; j++) {
4106 if ((i+j) >= matcher.to) {
4107 matcher.hitEnd = true;
4108 return false;
4109 }
4110 int c = seq.charAt(i+j);
4111 if (buf[j] != c &&
4112 buf[j] != ASCII.toLower(c))
4113 return false;
4114 }
4115 return next.match(matcher, i+len, seq);
4116 }
4117 }
4118
4119 /**
4120 * Node class for a unicode_case_insensitive/BMP-only sequence of
4121 * literal characters. Uses unicode case folding.
4122 */
4123 static final class SliceU extends SliceNode {
4124 SliceU(int[] buf) {
4125 super(buf);
4126 }
4127 boolean match(Matcher matcher, int i, CharSequence seq) {
4128 int[] buf = buffer;
4129 int len = buf.length;
4130 for (int j=0; j<len; j++) {
4131 if ((i+j) >= matcher.to) {
4132 matcher.hitEnd = true;
4133 return false;
4134 }
4135 int c = seq.charAt(i+j);
4136 if (buf[j] != c &&
4137 buf[j] != Character.toLowerCase(Character.toUpperCase(c)))
4138 return false;
4139 }
4140 return next.match(matcher, i+len, seq);
4141 }
4142 }
4143
4144 /**
4145 * Node class for a case sensitive sequence of literal characters
4146 * including supplementary characters.
4147 */
4148 static final class SliceS extends Slice {
4149 SliceS(int[] buf) {
4150 super(buf);
4151 }
4152 boolean match(Matcher matcher, int i, CharSequence seq) {
4153 int[] buf = buffer;
4154 int x = i;
4155 for (int j = 0; j < buf.length; j++) {
4156 if (x >= matcher.to) {
4157 matcher.hitEnd = true;
4158 return false;
4159 }
4160 int c = Character.codePointAt(seq, x);
4161 if (buf[j] != c)
4162 return false;
4163 x += Character.charCount(c);
4164 if (x > matcher.to) {
4165 matcher.hitEnd = true;
4166 return false;
4167 }
4168 }
4169 return next.match(matcher, x, seq);
4170 }
4171 }
4172
4173 /**
4174 * Node class for a case insensitive sequence of literal characters
4175 * including supplementary characters.
4176 */
4177 static class SliceIS extends SliceNode {
4178 SliceIS(int[] buf) {
4179 super(buf);
4180 }
4181 int toLower(int c) {
4182 return ASCII.toLower(c);
4183 }
4184 boolean match(Matcher matcher, int i, CharSequence seq) {
4185 int[] buf = buffer;
4186 int x = i;
4187 for (int j = 0; j < buf.length; j++) {
4188 if (x >= matcher.to) {
4189 matcher.hitEnd = true;
4190 return false;
4191 }
4192 int c = Character.codePointAt(seq, x);
4193 if (buf[j] != c && buf[j] != toLower(c))
4194 return false;
4195 x += Character.charCount(c);
4196 if (x > matcher.to) {
4197 matcher.hitEnd = true;
4198 return false;
4199 }
4200 }
4201 return next.match(matcher, x, seq);
4202 }
4203 }
4204
4205 /**
4206 * Node class for a case insensitive sequence of literal characters.
4207 * Uses unicode case folding.
4208 */
4209 static final class SliceUS extends SliceIS {
4210 SliceUS(int[] buf) {
4211 super(buf);
4212 }
4213 int toLower(int c) {
4214 return Character.toLowerCase(Character.toUpperCase(c));
4215 }
4216 }
4217
4218 /**
4219 * The 0 or 1 quantifier. This one class implements all three types.
4220 */
4221 static final class Ques extends Node {
4222 Node atom;
4223 Qtype type;
4224 Ques(Node node, Qtype type) {
4225 this.atom = node;
4226 this.type = type;
4227 }
4228 boolean match(Matcher matcher, int i, CharSequence seq) {
4229 switch (type) {
4230 case GREEDY:
4231 return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq))
4232 || next.match(matcher, i, seq);
4233 case LAZY:
4234 return next.match(matcher, i, seq)
4235 || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq));
4236 case POSSESSIVE:
4237 if (atom.match(matcher, i, seq)) i = matcher.last;
4238 return next.match(matcher, i, seq);
4239 default:
4240 return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq);
4241 }
4242 }
4243 boolean study(TreeInfo info) {
4244 if (type != Qtype.INDEPENDENT) {
4245 int minL = info.minLength;
4246 atom.study(info);
4247 info.minLength = minL;
4248 info.deterministic = false;
4249 return next.study(info);
4250 } else {
4251 atom.study(info);
4252 return next.study(info);
4253 }
4254 }
4255 }
4256
4257 /**
4258 * Handles the greedy style repetition with the minimum either be
4259 * 0 or 1 and the maximum be MAX_REPS, for * and + quantifier.
4260 */
4261 static class CharPropertyGreedy extends Node {
4262 final CharPredicate predicate;
4263 final int cmin;
4264
4265 CharPropertyGreedy(CharProperty cp, int cmin) {
4266 this.predicate = cp.predicate;
4267 this.cmin = cmin;
4268 }
4269 boolean match(Matcher matcher, int i, CharSequence seq) {
4270 int n = 0;
4271 int to = matcher.to;
4272 // greedy, all the way down
4273 while (i < to) {
4274 int ch = Character.codePointAt(seq, i);
4275 if (!predicate.is(ch))
4276 break;
4277 i += Character.charCount(ch);
4278 n++;
4279 }
4280 if (i >= to) {
4281 matcher.hitEnd = true;
4282 }
4283 while (n >= cmin) {
4284 if (next.match(matcher, i, seq))
4285 return true;
4286 if (n == cmin)
4287 return false;
4288 // backing off if match fails
4289 int ch = Character.codePointBefore(seq, i);
4290 i -= Character.charCount(ch);
4291 n--;
4292 }
4293 return false;
4294 }
4295
4296 boolean study(TreeInfo info) {
4297 info.minLength += cmin;
4298 if (info.maxValid) {
4299 info.maxLength += MAX_REPS;
4300 }
4301 info.deterministic = false;
4302 return next.study(info);
4303 }
4304 }
4305
4306 static final class BmpCharPropertyGreedy extends CharPropertyGreedy {
4307
4308 BmpCharPropertyGreedy(BmpCharProperty bcp, int cmin) {
4309 super(bcp, cmin);
4310 }
4311
4312 boolean match(Matcher matcher, int i, CharSequence seq) {
4313 int n = 0;
4314 int to = matcher.to;
4315 while (i < to && predicate.is(seq.charAt(i))) {
4316 i++; n++;
4317 }
4318 if (i >= to) {
4319 matcher.hitEnd = true;
4320 }
4321 while (n >= cmin) {
4322 if (next.match(matcher, i, seq))
4323 return true;
4324 i--; n--; // backing off if match fails
4325 }
4326 return false;
4327 }
4328 }
4329
4330 /**
4331 * Handles the curly-brace style repetition with a specified minimum and
4332 * maximum occurrences. The * quantifier is handled as a special case.
4333 * This class handles the three types.
4334 */
4335 static final class Curly extends Node {
4336 Node atom;
4337 Qtype type;
4338 int cmin;
4339 int cmax;
4340
4341 Curly(Node node, int cmin, int cmax, Qtype type) {
4342 this.atom = node;
4343 this.type = type;
4344 this.cmin = cmin;
4345 this.cmax = cmax;
4346 }
4347 boolean match(Matcher matcher, int i, CharSequence seq) {
4348 int j;
4349 for (j = 0; j < cmin; j++) {
4350 if (atom.match(matcher, i, seq)) {
4351 i = matcher.last;
4352 continue;
4353 }
4354 return false;
4355 }
4356 if (type == Qtype.GREEDY)
4357 return match0(matcher, i, j, seq);
4358 else if (type == Qtype.LAZY)
4359 return match1(matcher, i, j, seq);
4360 else
4361 return match2(matcher, i, j, seq);
4362 }
4363 // Greedy match.
4364 // i is the index to start matching at
4365 // j is the number of atoms that have matched
4366 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4367 if (j >= cmax) {
4368 // We have matched the maximum... continue with the rest of
4369 // the regular expression
4370 return next.match(matcher, i, seq);
4371 }
4372 int backLimit = j;
4373 while (atom.match(matcher, i, seq)) {
4374 // k is the length of this match
4375 int k = matcher.last - i;
4376 if (k == 0) // Zero length match
4377 break;
4378 // Move up index and number matched
4379 i = matcher.last;
4380 j++;
4381 // We are greedy so match as many as we can
4382 while (j < cmax) {
4383 if (!atom.match(matcher, i, seq))
4384 break;
4385 if (i + k != matcher.last) {
4386 if (match0(matcher, matcher.last, j+1, seq))
4387 return true;
4388 break;
4389 }
4390 i += k;
4391 j++;
4392 }
4393 // Handle backing off if match fails
4394 while (j >= backLimit) {
4395 if (next.match(matcher, i, seq))
4396 return true;
4397 i -= k;
4398 j--;
4399 }
4400 return false;
4401 }
4402 return next.match(matcher, i, seq);
4403 }
4404 // Reluctant match. At this point, the minimum has been satisfied.
4405 // i is the index to start matching at
4406 // j is the number of atoms that have matched
4407 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4408 for (;;) {
4409 // Try finishing match without consuming any more
4410 if (next.match(matcher, i, seq))
4411 return true;
4412 // At the maximum, no match found
4413 if (j >= cmax)
4414 return false;
4415 // Okay, must try one more atom
4416 if (!atom.match(matcher, i, seq))
4417 return false;
4418 // If we haven't moved forward then must break out
4419 if (i == matcher.last)
4420 return false;
4421 // Move up index and number matched
4422 i = matcher.last;
4423 j++;
4424 }
4425 }
4426 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4427 for (; j < cmax; j++) {
4428 if (!atom.match(matcher, i, seq))
4429 break;
4430 if (i == matcher.last)
4431 break;
4432 i = matcher.last;
4433 }
4434 return next.match(matcher, i, seq);
4435 }
4436 boolean study(TreeInfo info) {
4437 // Save original info
4438 int minL = info.minLength;
4439 int maxL = info.maxLength;
4440 boolean maxV = info.maxValid;
4441 boolean detm = info.deterministic;
4442 info.reset();
4443
4444 atom.study(info);
4445
4446 int temp = info.minLength * cmin + minL;
4447 if (temp < minL) {
4448 temp = 0xFFFFFFF; // arbitrary large number
4449 }
4450 info.minLength = temp;
4451
4452 if (maxV & info.maxValid) {
4453 temp = info.maxLength * cmax + maxL;
4454 info.maxLength = temp;
4455 if (temp < maxL) {
4456 info.maxValid = false;
4457 }
4458 } else {
4459 info.maxValid = false;
4460 }
4461
4462 if (info.deterministic && cmin == cmax)
4463 info.deterministic = detm;
4464 else
4465 info.deterministic = false;
4466 return next.study(info);
4467 }
4468 }
4469
4470 /**
4471 * Handles the curly-brace style repetition with a specified minimum and
4472 * maximum occurrences in deterministic cases. This is an iterative
4473 * optimization over the Prolog and Loop system which would handle this
4474 * in a recursive way. The * quantifier is handled as a special case.
4475 * If capture is true then this class saves group settings and ensures
4476 * that groups are unset when backing off of a group match.
4477 */
4478 static final class GroupCurly extends Node {
4479 Node atom;
4480 Qtype type;
4481 int cmin;
4482 int cmax;
4483 int localIndex;
4484 int groupIndex;
4485 boolean capture;
4486
4487 GroupCurly(Node node, int cmin, int cmax, Qtype type, int local,
4488 int group, boolean capture) {
4489 this.atom = node;
4490 this.type = type;
4491 this.cmin = cmin;
4492 this.cmax = cmax;
4493 this.localIndex = local;
4494 this.groupIndex = group;
4495 this.capture = capture;
4496 }
4497 boolean match(Matcher matcher, int i, CharSequence seq) {
4498 int[] groups = matcher.groups;
4499 int[] locals = matcher.locals;
4500 int save0 = locals[localIndex];
4501 int save1 = 0;
4502 int save2 = 0;
4503
4504 if (capture) {
4505 save1 = groups[groupIndex];
4506 save2 = groups[groupIndex+1];
4507 }
4508
4509 // Notify GroupTail there is no need to setup group info
4510 // because it will be set here
4511 locals[localIndex] = -1;
4512
4513 boolean ret = true;
4514 for (int j = 0; j < cmin; j++) {
4515 if (atom.match(matcher, i, seq)) {
4516 if (capture) {
4517 groups[groupIndex] = i;
4518 groups[groupIndex+1] = matcher.last;
4519 }
4520 i = matcher.last;
4521 } else {
4522 ret = false;
4523 break;
4524 }
4525 }
4526 if (ret) {
4527 if (type == Qtype.GREEDY) {
4528 ret = match0(matcher, i, cmin, seq);
4529 } else if (type == Qtype.LAZY) {
4530 ret = match1(matcher, i, cmin, seq);
4531 } else {
4532 ret = match2(matcher, i, cmin, seq);
4533 }
4534 }
4535 if (!ret) {
4536 locals[localIndex] = save0;
4537 if (capture) {
4538 groups[groupIndex] = save1;
4539 groups[groupIndex+1] = save2;
4540 }
4541 }
4542 return ret;
4543 }
4544 // Aggressive group match
4545 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4546 // don't back off passing the starting "j"
4547 int min = j;
4548 int[] groups = matcher.groups;
4549 int save0 = 0;
4550 int save1 = 0;
4551 if (capture) {
4552 save0 = groups[groupIndex];
4553 save1 = groups[groupIndex+1];
4554 }
4555 for (;;) {
4556 if (j >= cmax)
4557 break;
4558 if (!atom.match(matcher, i, seq))
4559 break;
4560 int k = matcher.last - i;
4561 if (k <= 0) {
4562 if (capture) {
4563 groups[groupIndex] = i;
4564 groups[groupIndex+1] = i + k;
4565 }
4566 i = i + k;
4567 break;
4568 }
4569 for (;;) {
4570 if (capture) {
4571 groups[groupIndex] = i;
4572 groups[groupIndex+1] = i + k;
4573 }
4574 i = i + k;
4575 if (++j >= cmax)
4576 break;
4577 if (!atom.match(matcher, i, seq))
4578 break;
4579 if (i + k != matcher.last) {
4580 if (match0(matcher, i, j, seq))
4581 return true;
4582 break;
4583 }
4584 }
4585 while (j > min) {
4586 if (next.match(matcher, i, seq)) {
4587 if (capture) {
4588 groups[groupIndex+1] = i;
4589 groups[groupIndex] = i - k;
4590 }
4591 return true;
4592 }
4593 // backing off
4594 i = i - k;
4595 if (capture) {
4596 groups[groupIndex+1] = i;
4597 groups[groupIndex] = i - k;
4598 }
4599 j--;
4600
4601 }
4602 break;
4603 }
4604 if (capture) {
4605 groups[groupIndex] = save0;
4606 groups[groupIndex+1] = save1;
4607 }
4608 return next.match(matcher, i, seq);
4609 }
4610 // Reluctant matching
4611 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4612 for (;;) {
4613 if (next.match(matcher, i, seq))
4614 return true;
4615 if (j >= cmax)
4616 return false;
4617 if (!atom.match(matcher, i, seq))
4618 return false;
4619 if (i == matcher.last)
4620 return false;
4621 if (capture) {
4622 matcher.groups[groupIndex] = i;
4623 matcher.groups[groupIndex+1] = matcher.last;
4624 }
4625 i = matcher.last;
4626 j++;
4627 }
4628 }
4629 // Possessive matching
4630 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4631 for (; j < cmax; j++) {
4632 if (!atom.match(matcher, i, seq)) {
4633 break;
4634 }
4635 if (capture) {
4636 matcher.groups[groupIndex] = i;
4637 matcher.groups[groupIndex+1] = matcher.last;
4638 }
4639 if (i == matcher.last) {
4640 break;
4641 }
4642 i = matcher.last;
4643 }
4644 return next.match(matcher, i, seq);
4645 }
4646 boolean study(TreeInfo info) {
4647 // Save original info
4648 int minL = info.minLength;
4649 int maxL = info.maxLength;
4650 boolean maxV = info.maxValid;
4651 boolean detm = info.deterministic;
4652 info.reset();
4653
4654 atom.study(info);
4655
4656 int temp = info.minLength * cmin + minL;
4657 if (temp < minL) {
4658 temp = 0xFFFFFFF; // Arbitrary large number
4659 }
4660 info.minLength = temp;
4661
4662 if (maxV & info.maxValid) {
4663 temp = info.maxLength * cmax + maxL;
4664 info.maxLength = temp;
4665 if (temp < maxL) {
4666 info.maxValid = false;
4667 }
4668 } else {
4669 info.maxValid = false;
4670 }
4671
4672 if (info.deterministic && cmin == cmax) {
4673 info.deterministic = detm;
4674 } else {
4675 info.deterministic = false;
4676 }
4677 return next.study(info);
4678 }
4679 }
4680
4681 /**
4682 * A Guard node at the end of each atom node in a Branch. It
4683 * serves the purpose of chaining the "match" operation to
4684 * "next" but not the "study", so we can collect the TreeInfo
4685 * of each atom node without including the TreeInfo of the
4686 * "next".
4687 */
4688 static final class BranchConn extends Node {
4689 BranchConn() {};
4690 boolean match(Matcher matcher, int i, CharSequence seq) {
4691 return next.match(matcher, i, seq);
4692 }
4693 boolean study(TreeInfo info) {
4694 return info.deterministic;
4695 }
4696 }
4697
4698 /**
4699 * Handles the branching of alternations. Note this is also used for
4700 * the ? quantifier to branch between the case where it matches once
4701 * and where it does not occur.
4702 */
4703 static final class Branch extends Node {
4704 Node[] atoms = new Node[2];
4705 int size = 2;
4706 Node conn;
4707 Branch(Node first, Node second, Node branchConn) {
4708 conn = branchConn;
4709 atoms[0] = first;
4710 atoms[1] = second;
4711 }
4712
4713 void add(Node node) {
4714 if (size >= atoms.length) {
4715 Node[] tmp = new Node[atoms.length*2];
4716 System.arraycopy(atoms, 0, tmp, 0, atoms.length);
4717 atoms = tmp;
4718 }
4719 atoms[size++] = node;
4720 }
4721
4722 boolean match(Matcher matcher, int i, CharSequence seq) {
4723 for (int n = 0; n < size; n++) {
4724 if (atoms[n] == null) {
4725 if (conn.next.match(matcher, i, seq))
4726 return true;
4727 } else if (atoms[n].match(matcher, i, seq)) {
4728 return true;
4729 }
4730 }
4731 return false;
4732 }
4733
4734 boolean study(TreeInfo info) {
4735 int minL = info.minLength;
4736 int maxL = info.maxLength;
4737 boolean maxV = info.maxValid;
4738
4739 int minL2 = Integer.MAX_VALUE; //arbitrary large enough num
4740 int maxL2 = -1;
4741 for (int n = 0; n < size; n++) {
4742 info.reset();
4743 if (atoms[n] != null)
4744 atoms[n].study(info);
4745 minL2 = Math.min(minL2, info.minLength);
4746 maxL2 = Math.max(maxL2, info.maxLength);
4747 maxV = (maxV & info.maxValid);
4748 }
4749
4750 minL += minL2;
4751 maxL += maxL2;
4752
4753 info.reset();
4754 conn.next.study(info);
4755
4756 info.minLength += minL;
4757 info.maxLength += maxL;
4758 info.maxValid &= maxV;
4759 info.deterministic = false;
4760 return false;
4761 }
4762 }
4763
4764 /**
4765 * The GroupHead saves the location where the group begins in the locals
4766 * and restores them when the match is done.
4767 *
4768 * The matchRef is used when a reference to this group is accessed later
4769 * in the expression. The locals will have a negative value in them to
4770 * indicate that we do not want to unset the group if the reference
4771 * doesn't match.
4772 */
4773 static final class GroupHead extends Node {
4774 int localIndex;
4775 GroupTail tail; // for debug/print only, match does not need to know
4776 GroupHead(int localCount) {
4777 localIndex = localCount;
4778 }
4779 boolean match(Matcher matcher, int i, CharSequence seq) {
4780 int save = matcher.locals[localIndex];
4781 matcher.locals[localIndex] = i;
4782 boolean ret = next.match(matcher, i, seq);
4783 matcher.locals[localIndex] = save;
4784 return ret;
4785 }
4786 boolean matchRef(Matcher matcher, int i, CharSequence seq) {
4787 int save = matcher.locals[localIndex];
4788 matcher.locals[localIndex] = ~i; // HACK
4789 boolean ret = next.match(matcher, i, seq);
4790 matcher.locals[localIndex] = save;
4791 return ret;
4792 }
4793 }
4794
4795 /**
4796 * Recursive reference to a group in the regular expression. It calls
4797 * matchRef because if the reference fails to match we would not unset
4798 * the group.
4799 */
4800 static final class GroupRef extends Node {
4801 GroupHead head;
4802 GroupRef(GroupHead head) {
4803 this.head = head;
4804 }
4805 boolean match(Matcher matcher, int i, CharSequence seq) {
4806 return head.matchRef(matcher, i, seq)
4807 && next.match(matcher, matcher.last, seq);
4808 }
4809 boolean study(TreeInfo info) {
4810 info.maxValid = false;
4811 info.deterministic = false;
4812 return next.study(info);
4813 }
4814 }
4815
4816 /**
4817 * The GroupTail handles the setting of group beginning and ending
4818 * locations when groups are successfully matched. It must also be able to
4819 * unset groups that have to be backed off of.
4820 *
4821 * The GroupTail node is also used when a previous group is referenced,
4822 * and in that case no group information needs to be set.
4823 */
4824 static final class GroupTail extends Node {
4825 int localIndex;
4826 int groupIndex;
4827 GroupTail(int localCount, int groupCount) {
4828 localIndex = localCount;
4829 groupIndex = groupCount + groupCount;
4830 }
4831 boolean match(Matcher matcher, int i, CharSequence seq) {
4832 int tmp = matcher.locals[localIndex];
4833 if (tmp >= 0) { // This is the normal group case.
4834 // Save the group so we can unset it if it
4835 // backs off of a match.
4836 int groupStart = matcher.groups[groupIndex];
4837 int groupEnd = matcher.groups[groupIndex+1];
4838
4839 matcher.groups[groupIndex] = tmp;
4840 matcher.groups[groupIndex+1] = i;
4841 if (next.match(matcher, i, seq)) {
4842 return true;
4843 }
4844 matcher.groups[groupIndex] = groupStart;
4845 matcher.groups[groupIndex+1] = groupEnd;
4846 return false;
4847 } else {
4848 // This is a group reference case. We don't need to save any
4849 // group info because it isn't really a group.
4850 matcher.last = i;
4851 return true;
4852 }
4853 }
4854 }
4855
4856 /**
4857 * This sets up a loop to handle a recursive quantifier structure.
4858 */
4859 static final class Prolog extends Node {
4860 Loop loop;
4861 Prolog(Loop loop) {
4862 this.loop = loop;
4863 }
4864 boolean match(Matcher matcher, int i, CharSequence seq) {
4865 return loop.matchInit(matcher, i, seq);
4866 }
4867 boolean study(TreeInfo info) {
4868 return loop.study(info);
4869 }
4870 }
4871
4872 /**
4873 * Handles the repetition count for a greedy Curly. The matchInit
4874 * is called from the Prolog to save the index of where the group
4875 * beginning is stored. A zero length group check occurs in the
4876 * normal match but is skipped in the matchInit.
4877 */
4878 static class Loop extends Node {
4879 Node body;
4880 int countIndex; // local count index in matcher locals
4881 int beginIndex; // group beginning index
4882 int cmin, cmax;
4883 int posIndex;
4884 Loop(int countIndex, int beginIndex) {
4885 this.countIndex = countIndex;
4886 this.beginIndex = beginIndex;
4887 this.posIndex = -1;
4888 }
4889 boolean match(Matcher matcher, int i, CharSequence seq) {
4890 // Avoid infinite loop in zero-length case.
4891 if (i > matcher.locals[beginIndex]) {
4892 int count = matcher.locals[countIndex];
4893
4894 // This block is for before we reach the minimum
4895 // iterations required for the loop to match
4896 if (count < cmin) {
4897 matcher.locals[countIndex] = count + 1;
4898 boolean b = body.match(matcher, i, seq);
4899 // If match failed we must backtrack, so
4900 // the loop count should NOT be incremented
4901 if (!b)
4902 matcher.locals[countIndex] = count;
4903 // Return success or failure since we are under
4904 // minimum
4905 return b;
4906 }
4907 // This block is for after we have the minimum
4908 // iterations required for the loop to match
4909 if (count < cmax) {
4910 // Let's check if we have already tried and failed
4911 // at this starting position "i" in the past.
4912 // If yes, then just return false wihtout trying
4913 // again, to stop the exponential backtracking.
4914 if (posIndex != -1 &&
4915 matcher.localsPos[posIndex].contains(i)) {
4916 return next.match(matcher, i, seq);
4917 }
4918 matcher.locals[countIndex] = count + 1;
4919 boolean b = body.match(matcher, i, seq);
4920 // If match failed we must backtrack, so
4921 // the loop count should NOT be incremented
4922 if (b)
4923 return true;
4924 matcher.locals[countIndex] = count;
4925 // save the failed position
4926 if (posIndex != -1) {
4927 matcher.localsPos[posIndex].add(i);
4928 }
4929 }
4930 }
4931 return next.match(matcher, i, seq);
4932 }
4933 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4934 int save = matcher.locals[countIndex];
4935 boolean ret = false;
4936 if (posIndex != -1 && matcher.localsPos[posIndex] == null) {
4937 matcher.localsPos[posIndex] = new IntHashSet();
4938 }
4939 if (0 < cmin) {
4940 matcher.locals[countIndex] = 1;
4941 ret = body.match(matcher, i, seq);
4942 } else if (0 < cmax) {
4943 matcher.locals[countIndex] = 1;
4944 ret = body.match(matcher, i, seq);
4945 if (ret == false)
4946 ret = next.match(matcher, i, seq);
4947 } else {
4948 ret = next.match(matcher, i, seq);
4949 }
4950 matcher.locals[countIndex] = save;
4951 return ret;
4952 }
4953 boolean study(TreeInfo info) {
4954 info.maxValid = false;
4955 info.deterministic = false;
4956 return false;
4957 }
4958 }
4959
4960 /**
4961 * Handles the repetition count for a reluctant Curly. The matchInit
4962 * is called from the Prolog to save the index of where the group
4963 * beginning is stored. A zero length group check occurs in the
4964 * normal match but is skipped in the matchInit.
4965 */
4966 static final class LazyLoop extends Loop {
4967 LazyLoop(int countIndex, int beginIndex) {
4968 super(countIndex, beginIndex);
4969 }
4970 boolean match(Matcher matcher, int i, CharSequence seq) {
4971 // Check for zero length group
4972 if (i > matcher.locals[beginIndex]) {
4973 int count = matcher.locals[countIndex];
4974 if (count < cmin) {
4975 matcher.locals[countIndex] = count + 1;
4976 boolean result = body.match(matcher, i, seq);
4977 // If match failed we must backtrack, so
4978 // the loop count should NOT be incremented
4979 if (!result)
4980 matcher.locals[countIndex] = count;
4981 return result;
4982 }
4983 if (next.match(matcher, i, seq))
4984 return true;
4985 if (count < cmax) {
4986 matcher.locals[countIndex] = count + 1;
4987 boolean result = body.match(matcher, i, seq);
4988 // If match failed we must backtrack, so
4989 // the loop count should NOT be incremented
4990 if (!result)
4991 matcher.locals[countIndex] = count;
4992 return result;
4993 }
4994 return false;
4995 }
4996 return next.match(matcher, i, seq);
4997 }
4998 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4999 int save = matcher.locals[countIndex];
5000 boolean ret = false;
5001 if (0 < cmin) {
5002 matcher.locals[countIndex] = 1;
5003 ret = body.match(matcher, i, seq);
5004 } else if (next.match(matcher, i, seq)) {
5005 ret = true;
5006 } else if (0 < cmax) {
5007 matcher.locals[countIndex] = 1;
5008 ret = body.match(matcher, i, seq);
5009 }
5010 matcher.locals[countIndex] = save;
5011 return ret;
5012 }
5013 boolean study(TreeInfo info) {
5014 info.maxValid = false;
5015 info.deterministic = false;
5016 return false;
5017 }
5018 }
5019
5020 /**
5021 * Refers to a group in the regular expression. Attempts to match
5022 * whatever the group referred to last matched.
5023 */
5024 static class BackRef extends Node {
5025 int groupIndex;
5026 BackRef(int groupCount) {
5027 super();
5028 groupIndex = groupCount + groupCount;
5029 }
5030 boolean match(Matcher matcher, int i, CharSequence seq) {
5031 int j = matcher.groups[groupIndex];
5032 int k = matcher.groups[groupIndex+1];
5033
5034 int groupSize = k - j;
5035 // If the referenced group didn't match, neither can this
5036 if (j < 0)
5037 return false;
5038
5039 // If there isn't enough input left no match
5040 if (i + groupSize > matcher.to) {
5041 matcher.hitEnd = true;
5042 return false;
5043 }
5044 // Check each new char to make sure it matches what the group
5045 // referenced matched last time around
5046 for (int index=0; index<groupSize; index++)
5047 if (seq.charAt(i+index) != seq.charAt(j+index))
5048 return false;
5049
5050 return next.match(matcher, i+groupSize, seq);
5051 }
5052 boolean study(TreeInfo info) {
5053 info.maxValid = false;
5054 return next.study(info);
5055 }
5056 }
5057
5058 static class CIBackRef extends Node {
5059 int groupIndex;
5060 boolean doUnicodeCase;
5061 CIBackRef(int groupCount, boolean doUnicodeCase) {
5062 super();
5063 groupIndex = groupCount + groupCount;
5064 this.doUnicodeCase = doUnicodeCase;
5065 }
5066 boolean match(Matcher matcher, int i, CharSequence seq) {
5067 int j = matcher.groups[groupIndex];
5068 int k = matcher.groups[groupIndex+1];
5069
5070 int groupSize = k - j;
5071
5072 // If the referenced group didn't match, neither can this
5073 if (j < 0)
5074 return false;
5075
5076 // If there isn't enough input left no match
5077 if (i + groupSize > matcher.to) {
5078 matcher.hitEnd = true;
5079 return false;
5080 }
5081
5082 // Check each new char to make sure it matches what the group
5083 // referenced matched last time around
5084 int x = i;
5085 for (int index=0; index<groupSize; index++) {
5086 int c1 = Character.codePointAt(seq, x);
5087 int c2 = Character.codePointAt(seq, j);
5088 if (c1 != c2) {
5089 if (doUnicodeCase) {
5090 int cc1 = Character.toUpperCase(c1);
5091 int cc2 = Character.toUpperCase(c2);
5092 if (cc1 != cc2 &&
5093 Character.toLowerCase(cc1) !=
5094 Character.toLowerCase(cc2))
5095 return false;
5096 } else {
5097 if (ASCII.toLower(c1) != ASCII.toLower(c2))
5098 return false;
5099 }
5100 }
5101 x += Character.charCount(c1);
5102 j += Character.charCount(c2);
5103 }
5104
5105 return next.match(matcher, i+groupSize, seq);
5106 }
5107 boolean study(TreeInfo info) {
5108 info.maxValid = false;
5109 return next.study(info);
5110 }
5111 }
5112
5113 /**
5114 * Searches until the next instance of its atom. This is useful for
5115 * finding the atom efficiently without passing an instance of it
5116 * (greedy problem) and without a lot of wasted search time (reluctant
5117 * problem).
5118 */
5119 static final class First extends Node {
5120 Node atom;
5121 First(Node node) {
5122 this.atom = BnM.optimize(node);
5123 }
5124 boolean match(Matcher matcher, int i, CharSequence seq) {
5125 if (atom instanceof BnM) {
5126 return atom.match(matcher, i, seq)
5127 && next.match(matcher, matcher.last, seq);
5128 }
5129 for (;;) {
5130 if (i > matcher.to) {
5131 matcher.hitEnd = true;
5132 return false;
5133 }
5134 if (atom.match(matcher, i, seq)) {
5135 return next.match(matcher, matcher.last, seq);
5136 }
5137 i += countChars(seq, i, 1);
5138 matcher.first++;
5139 }
5140 }
5141 boolean study(TreeInfo info) {
5142 atom.study(info);
5143 info.maxValid = false;
5144 info.deterministic = false;
5145 return next.study(info);
5146 }
5147 }
5148
5149 static final class Conditional extends Node {
5150 Node cond, yes, not;
5151 Conditional(Node cond, Node yes, Node not) {
5152 this.cond = cond;
5153 this.yes = yes;
5154 this.not = not;
5155 }
5156 boolean match(Matcher matcher, int i, CharSequence seq) {
5157 if (cond.match(matcher, i, seq)) {
5158 return yes.match(matcher, i, seq);
5159 } else {
5160 return not.match(matcher, i, seq);
5161 }
5162 }
5163 boolean study(TreeInfo info) {
5164 int minL = info.minLength;
5165 int maxL = info.maxLength;
5166 boolean maxV = info.maxValid;
5167 info.reset();
5168 yes.study(info);
5169
5170 int minL2 = info.minLength;
5171 int maxL2 = info.maxLength;
5172 boolean maxV2 = info.maxValid;
5173 info.reset();
5174 not.study(info);
5175
5176 info.minLength = minL + Math.min(minL2, info.minLength);
5177 info.maxLength = maxL + Math.max(maxL2, info.maxLength);
5178 info.maxValid = (maxV & maxV2 & info.maxValid);
5179 info.deterministic = false;
5180 return next.study(info);
5181 }
5182 }
5183
5184 /**
5185 * Zero width positive lookahead.
5186 */
5187 static final class Pos extends Node {
5188 Node cond;
5189 Pos(Node cond) {
5190 this.cond = cond;
5191 }
5192 boolean match(Matcher matcher, int i, CharSequence seq) {
5193 int savedTo = matcher.to;
5194 boolean conditionMatched = false;
5195
5196 // Relax transparent region boundaries for lookahead
5197 if (matcher.transparentBounds)
5198 matcher.to = matcher.getTextLength();
5199 try {
5200 conditionMatched = cond.match(matcher, i, seq);
5201 } finally {
5202 // Reinstate region boundaries
5203 matcher.to = savedTo;
5204 }
5205 return conditionMatched && next.match(matcher, i, seq);
5206 }
5207 }
5208
5209 /**
5210 * Zero width negative lookahead.
5211 */
5212 static final class Neg extends Node {
5213 Node cond;
5214 Neg(Node cond) {
5215 this.cond = cond;
5216 }
5217 boolean match(Matcher matcher, int i, CharSequence seq) {
5218 int savedTo = matcher.to;
5219 boolean conditionMatched = false;
5220
5221 // Relax transparent region boundaries for lookahead
5222 if (matcher.transparentBounds)
5223 matcher.to = matcher.getTextLength();
5224 try {
5225 if (i < matcher.to) {
5226 conditionMatched = !cond.match(matcher, i, seq);
5227 } else {
5228 // If a negative lookahead succeeds then more input
5229 // could cause it to fail!
5230 matcher.requireEnd = true;
5231 conditionMatched = !cond.match(matcher, i, seq);
5232 }
5233 } finally {
5234 // Reinstate region boundaries
5235 matcher.to = savedTo;
5236 }
5237 return conditionMatched && next.match(matcher, i, seq);
5238 }
5239 }
5240
5241 /**
5242 * For use with lookbehinds; matches the position where the lookbehind
5243 * was encountered.
5244 */
5245 static Node lookbehindEnd = new Node() {
5246 boolean match(Matcher matcher, int i, CharSequence seq) {
5247 return i == matcher.lookbehindTo;
5248 }
5249 };
5250
5251 /**
5252 * Zero width positive lookbehind.
5253 */
5254 static class Behind extends Node {
5255 Node cond;
5256 int rmax, rmin;
5257 Behind(Node cond, int rmax, int rmin) {
5258 this.cond = cond;
5259 this.rmax = rmax;
5260 this.rmin = rmin;
5261 }
5262
5263 boolean match(Matcher matcher, int i, CharSequence seq) {
5264 int savedFrom = matcher.from;
5265 boolean conditionMatched = false;
5266 int startIndex = (!matcher.transparentBounds) ?
5267 matcher.from : 0;
5268 int from = Math.max(i - rmax, startIndex);
5269 // Set end boundary
5270 int savedLBT = matcher.lookbehindTo;
5271 matcher.lookbehindTo = i;
5272 // Relax transparent region boundaries for lookbehind
5273 if (matcher.transparentBounds)
5274 matcher.from = 0;
5275 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5276 conditionMatched = cond.match(matcher, j, seq);
5277 }
5278 matcher.from = savedFrom;
5279 matcher.lookbehindTo = savedLBT;
5280 return conditionMatched && next.match(matcher, i, seq);
5281 }
5282 }
5283
5284 /**
5285 * Zero width positive lookbehind, including supplementary
5286 * characters or unpaired surrogates.
5287 */
5288 static final class BehindS extends Behind {
5289 BehindS(Node cond, int rmax, int rmin) {
5290 super(cond, rmax, rmin);
5291 }
5292 boolean match(Matcher matcher, int i, CharSequence seq) {
5293 int rmaxChars = countChars(seq, i, -rmax);
5294 int rminChars = countChars(seq, i, -rmin);
5295 int savedFrom = matcher.from;
5296 int startIndex = (!matcher.transparentBounds) ?
5297 matcher.from : 0;
5298 boolean conditionMatched = false;
5299 int from = Math.max(i - rmaxChars, startIndex);
5300 // Set end boundary
5301 int savedLBT = matcher.lookbehindTo;
5302 matcher.lookbehindTo = i;
5303 // Relax transparent region boundaries for lookbehind
5304 if (matcher.transparentBounds)
5305 matcher.from = 0;
5306
5307 for (int j = i - rminChars;
5308 !conditionMatched && j >= from;
5309 j -= j>from ? countChars(seq, j, -1) : 1) {
5310 conditionMatched = cond.match(matcher, j, seq);
5311 }
5312 matcher.from = savedFrom;
5313 matcher.lookbehindTo = savedLBT;
5314 return conditionMatched && next.match(matcher, i, seq);
5315 }
5316 }
5317
5318 /**
5319 * Zero width negative lookbehind.
5320 */
5321 static class NotBehind extends Node {
5322 Node cond;
5323 int rmax, rmin;
5324 NotBehind(Node cond, int rmax, int rmin) {
5325 this.cond = cond;
5326 this.rmax = rmax;
5327 this.rmin = rmin;
5328 }
5329
5330 boolean match(Matcher matcher, int i, CharSequence seq) {
5331 int savedLBT = matcher.lookbehindTo;
5332 int savedFrom = matcher.from;
5333 boolean conditionMatched = false;
5334 int startIndex = (!matcher.transparentBounds) ?
5335 matcher.from : 0;
5336 int from = Math.max(i - rmax, startIndex);
5337 matcher.lookbehindTo = i;
5338 // Relax transparent region boundaries for lookbehind
5339 if (matcher.transparentBounds)
5340 matcher.from = 0;
5341 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5342 conditionMatched = cond.match(matcher, j, seq);
5343 }
5344 // Reinstate region boundaries
5345 matcher.from = savedFrom;
5346 matcher.lookbehindTo = savedLBT;
5347 return !conditionMatched && next.match(matcher, i, seq);
5348 }
5349 }
5350
5351 /**
5352 * Zero width negative lookbehind, including supplementary
5353 * characters or unpaired surrogates.
5354 */
5355 static final class NotBehindS extends NotBehind {
5356 NotBehindS(Node cond, int rmax, int rmin) {
5357 super(cond, rmax, rmin);
5358 }
5359 boolean match(Matcher matcher, int i, CharSequence seq) {
5360 int rmaxChars = countChars(seq, i, -rmax);
5361 int rminChars = countChars(seq, i, -rmin);
5362 int savedFrom = matcher.from;
5363 int savedLBT = matcher.lookbehindTo;
5364 boolean conditionMatched = false;
5365 int startIndex = (!matcher.transparentBounds) ?
5366 matcher.from : 0;
5367 int from = Math.max(i - rmaxChars, startIndex);
5368 matcher.lookbehindTo = i;
5369 // Relax transparent region boundaries for lookbehind
5370 if (matcher.transparentBounds)
5371 matcher.from = 0;
5372 for (int j = i - rminChars;
5373 !conditionMatched && j >= from;
5374 j -= j>from ? countChars(seq, j, -1) : 1) {
5375 conditionMatched = cond.match(matcher, j, seq);
5376 }
5377 //Reinstate region boundaries
5378 matcher.from = savedFrom;
5379 matcher.lookbehindTo = savedLBT;
5380 return !conditionMatched && next.match(matcher, i, seq);
5381 }
5382 }
5383
5384 /**
5385 * Handles word boundaries. Includes a field to allow this one class to
5386 * deal with the different types of word boundaries we can match. The word
5387 * characters include underscores, letters, and digits. Non spacing marks
5388 * can are also part of a word if they have a base character, otherwise
5389 * they are ignored for purposes of finding word boundaries.
5390 */
5391 static final class Bound extends Node {
5392 static int LEFT = 0x1;
5393 static int RIGHT= 0x2;
5394 static int BOTH = 0x3;
5395 static int NONE = 0x4;
5396 int type;
5397 boolean useUWORD;
5398 Bound(int n, boolean useUWORD) {
5399 type = n;
5400 this.useUWORD = useUWORD;
5401 }
5402
5403 boolean isWord(int ch) {
5404 return useUWORD ? CharPredicates.WORD().is(ch)
5405 : (ch == '_' || Character.isLetterOrDigit(ch));
5406 }
5407
5408 int check(Matcher matcher, int i, CharSequence seq) {
5409 int ch;
5410 boolean left = false;
5411 int startIndex = matcher.from;
5412 int endIndex = matcher.to;
5413 if (matcher.transparentBounds) {
5414 startIndex = 0;
5415 endIndex = matcher.getTextLength();
5416 }
5417 if (i > startIndex) {
5418 ch = Character.codePointBefore(seq, i);
5419 left = (isWord(ch) ||
5420 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5421 && hasBaseCharacter(matcher, i-1, seq)));
5422 }
5423 boolean right = false;
5424 if (i < endIndex) {
5425 ch = Character.codePointAt(seq, i);
5426 right = (isWord(ch) ||
5427 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5428 && hasBaseCharacter(matcher, i, seq)));
5429 } else {
5430 // Tried to access char past the end
5431 matcher.hitEnd = true;
5432 // The addition of another char could wreck a boundary
5433 matcher.requireEnd = true;
5434 }
5435 return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE);
5436 }
5437 boolean match(Matcher matcher, int i, CharSequence seq) {
5438 return (check(matcher, i, seq) & type) > 0
5439 && next.match(matcher, i, seq);
5440 }
5441 }
5442
5443 /**
5444 * Non spacing marks only count as word characters in bounds calculations
5445 * if they have a base character.
5446 */
5447 private static boolean hasBaseCharacter(Matcher matcher, int i,
5448 CharSequence seq)
5449 {
5450 int start = (!matcher.transparentBounds) ?
5451 matcher.from : 0;
5452 for (int x=i; x >= start; x--) {
5453 int ch = Character.codePointAt(seq, x);
5454 if (Character.isLetterOrDigit(ch))
5455 return true;
5456 if (Character.getType(ch) == Character.NON_SPACING_MARK)
5457 continue;
5458 return false;
5459 }
5460 return false;
5461 }
5462
5463 /**
5464 * Attempts to match a slice in the input using the Boyer-Moore string
5465 * matching algorithm. The algorithm is based on the idea that the
5466 * pattern can be shifted farther ahead in the search text if it is
5467 * matched right to left.
5468 * <p>
5469 * The pattern is compared to the input one character at a time, from
5470 * the rightmost character in the pattern to the left. If the characters
5471 * all match the pattern has been found. If a character does not match,
5472 * the pattern is shifted right a distance that is the maximum of two
5473 * functions, the bad character shift and the good suffix shift. This
5474 * shift moves the attempted match position through the input more
5475 * quickly than a naive one position at a time check.
5476 * <p>
5477 * The bad character shift is based on the character from the text that
5478 * did not match. If the character does not appear in the pattern, the
5479 * pattern can be shifted completely beyond the bad character. If the
5480 * character does occur in the pattern, the pattern can be shifted to
5481 * line the pattern up with the next occurrence of that character.
5482 * <p>
5483 * The good suffix shift is based on the idea that some subset on the right
5484 * side of the pattern has matched. When a bad character is found, the
5485 * pattern can be shifted right by the pattern length if the subset does
5486 * not occur again in pattern, or by the amount of distance to the
5487 * next occurrence of the subset in the pattern.
5488 *
5489 * Boyer-Moore search methods adapted from code by Amy Yu.
5490 */
5491 static class BnM extends Node {
5492 int[] buffer;
5493 int[] lastOcc;
5494 int[] optoSft;
5495
5496 /**
5497 * Pre calculates arrays needed to generate the bad character
5498 * shift and the good suffix shift. Only the last seven bits
5499 * are used to see if chars match; This keeps the tables small
5500 * and covers the heavily used ASCII range, but occasionally
5501 * results in an aliased match for the bad character shift.
5502 */
5503 static Node optimize(Node node) {
5504 if (!(node instanceof Slice)) {
5505 return node;
5506 }
5507
5508 int[] src = ((Slice) node).buffer;
5509 int patternLength = src.length;
5510 // The BM algorithm requires a bit of overhead;
5511 // If the pattern is short don't use it, since
5512 // a shift larger than the pattern length cannot
5513 // be used anyway.
5514 if (patternLength < 4) {
5515 return node;
5516 }
5517 int i, j, k;
5518 int[] lastOcc = new int[128];
5519 int[] optoSft = new int[patternLength];
5520 // Precalculate part of the bad character shift
5521 // It is a table for where in the pattern each
5522 // lower 7-bit value occurs
5523 for (i = 0; i < patternLength; i++) {
5524 lastOcc[src[i]&0x7F] = i + 1;
5525 }
5526 // Precalculate the good suffix shift
5527 // i is the shift amount being considered
5528 NEXT: for (i = patternLength; i > 0; i--) {
5529 // j is the beginning index of suffix being considered
5530 for (j = patternLength - 1; j >= i; j--) {
5531 // Testing for good suffix
5532 if (src[j] == src[j-i]) {
5533 // src[j..len] is a good suffix
5534 optoSft[j-1] = i;
5535 } else {
5536 // No match. The array has already been
5537 // filled up with correct values before.
5538 continue NEXT;
5539 }
5540 }
5541 // This fills up the remaining of optoSft
5542 // any suffix can not have larger shift amount
5543 // then its sub-suffix. Why???
5544 while (j > 0) {
5545 optoSft[--j] = i;
5546 }
5547 }
5548 // Set the guard value because of unicode compression
5549 optoSft[patternLength-1] = 1;
5550 if (node instanceof SliceS)
5551 return new BnMS(src, lastOcc, optoSft, node.next);
5552 return new BnM(src, lastOcc, optoSft, node.next);
5553 }
5554 BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5555 this.buffer = src;
5556 this.lastOcc = lastOcc;
5557 this.optoSft = optoSft;
5558 this.next = next;
5559 }
5560 boolean match(Matcher matcher, int i, CharSequence seq) {
5561 int[] src = buffer;
5562 int patternLength = src.length;
5563 int last = matcher.to - patternLength;
5564
5565 // Loop over all possible match positions in text
5566 NEXT: while (i <= last) {
5567 // Loop over pattern from right to left
5568 for (int j = patternLength - 1; j >= 0; j--) {
5569 int ch = seq.charAt(i+j);
5570 if (ch != src[j]) {
5571 // Shift search to the right by the maximum of the
5572 // bad character shift and the good suffix shift
5573 i += Math.max(j + 1 - lastOcc[ch&0x7F], optoSft[j]);
5574 continue NEXT;
5575 }
5576 }
5577 // Entire pattern matched starting at i
5578 matcher.first = i;
5579 boolean ret = next.match(matcher, i + patternLength, seq);
5580 if (ret) {
5581 matcher.first = i;
5582 matcher.groups[0] = matcher.first;
5583 matcher.groups[1] = matcher.last;
5584 return true;
5585 }
5586 i++;
5587 }
5588 // BnM is only used as the leading node in the unanchored case,
5589 // and it replaced its Start() which always searches to the end
5590 // if it doesn't find what it's looking for, so hitEnd is true.
5591 matcher.hitEnd = true;
5592 return false;
5593 }
5594 boolean study(TreeInfo info) {
5595 info.minLength += buffer.length;
5596 info.maxValid = false;
5597 return next.study(info);
5598 }
5599 }
5600
5601 /**
5602 * Supplementary support version of BnM(). Unpaired surrogates are
5603 * also handled by this class.
5604 */
5605 static final class BnMS extends BnM {
5606 int lengthInChars;
5607
5608 BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5609 super(src, lastOcc, optoSft, next);
5610 for (int cp : buffer) {
5611 lengthInChars += Character.charCount(cp);
5612 }
5613 }
5614 boolean match(Matcher matcher, int i, CharSequence seq) {
5615 int[] src = buffer;
5616 int patternLength = src.length;
5617 int last = matcher.to - lengthInChars;
5618
5619 // Loop over all possible match positions in text
5620 NEXT: while (i <= last) {
5621 // Loop over pattern from right to left
5622 int ch;
5623 for (int j = countChars(seq, i, patternLength), x = patternLength - 1;
5624 j > 0; j -= Character.charCount(ch), x--) {
5625 ch = Character.codePointBefore(seq, i+j);
5626 if (ch != src[x]) {
5627 // Shift search to the right by the maximum of the
5628 // bad character shift and the good suffix shift
5629 int n = Math.max(x + 1 - lastOcc[ch&0x7F], optoSft[x]);
5630 i += countChars(seq, i, n);
5631 continue NEXT;
5632 }
5633 }
5634 // Entire pattern matched starting at i
5635 matcher.first = i;
5636 boolean ret = next.match(matcher, i + lengthInChars, seq);
5637 if (ret) {
5638 matcher.first = i;
5639 matcher.groups[0] = matcher.first;
5640 matcher.groups[1] = matcher.last;
5641 return true;
5642 }
5643 i += countChars(seq, i, 1);
5644 }
5645 matcher.hitEnd = true;
5646 return false;
5647 }
5648 }
5649
5650 @FunctionalInterface
5651 static interface CharPredicate {
5652 boolean is(int ch);
5653
5654 default CharPredicate and(CharPredicate p) {
5655 return ch -> is(ch) && p.is(ch);
5656 }
5657 default CharPredicate union(CharPredicate p) {
5658 return ch -> is(ch) || p.is(ch);
5659 }
5660 default CharPredicate union(CharPredicate p1,
5661 CharPredicate p2 ) {
5662 return ch -> is(ch) || p1.is(ch) || p2.is(ch);
5663 }
5664 default CharPredicate negate() {
5665 return ch -> !is(ch);
5666 }
5667 }
5668
5669 static interface BmpCharPredicate extends CharPredicate {
5670
5671 default CharPredicate and(CharPredicate p) {
5672 if(p instanceof BmpCharPredicate)
5673 return (BmpCharPredicate)(ch -> is(ch) && p.is(ch));
5674 return ch -> is(ch) && p.is(ch);
5675 }
5676 default CharPredicate union(CharPredicate p) {
5677 if (p instanceof BmpCharPredicate)
5678 return (BmpCharPredicate)(ch -> is(ch) || p.is(ch));
5679 return ch -> is(ch) || p.is(ch);
5680 }
5681 static CharPredicate union(CharPredicate... predicates) {
5682 CharPredicate cp = ch -> {
5683 for (CharPredicate p : predicates) {
5684 if (!p.is(ch))
5685 return false;
5686 }
5687 return true;
5688 };
5689 for (CharPredicate p : predicates) {
5690 if (! (p instanceof BmpCharPredicate))
5691 return cp;
5692 }
5693 return (BmpCharPredicate)cp;
5694 }
5695 }
5696
5697 /**
5698 * matches a Perl vertical whitespace
5699 */
5700 static BmpCharPredicate VertWS() {
5701 return cp -> (cp >= 0x0A && cp <= 0x0D) ||
5702 cp == 0x85 || cp == 0x2028 || cp == 0x2029;
5703 }
5704
5705 /**
5706 * matches a Perl horizontal whitespace
5707 */
5708 static BmpCharPredicate HorizWS() {
5709 return cp ->
5710 cp == 0x09 || cp == 0x20 || cp == 0xa0 || cp == 0x1680 ||
5711 cp == 0x180e || cp >= 0x2000 && cp <= 0x200a || cp == 0x202f ||
5712 cp == 0x205f || cp == 0x3000;
5713 }
5714
5715 /**
5716 * for the Unicode category ALL and the dot metacharacter when
5717 * in dotall mode.
5718 */
5719 static CharPredicate ALL() {
5720 return ch -> true;
5721 }
5722
5723 /**
5724 * for the dot metacharacter when dotall is not enabled.
5725 */
5726 static CharPredicate DOT() {
5727 return ch ->
5728 (ch != '\n' && ch != '\r'
5729 && (ch|1) != '\u2029'
5730 && ch != '\u0085');
5731 }
5732
5733 /**
5734 * the dot metacharacter when dotall is not enabled but UNIX_LINES is enabled.
5735 */
5736 static CharPredicate UNIXDOT() {
5737 return ch -> ch != '\n';
5738 }
5739
5740 /**
5741 * Indicate that matches a Supplementary Unicode character
5742 */
5743 static CharPredicate SingleS(int c) {
5744 return ch -> ch == c;
5745 }
5746
5747 /**
5748 * A bmp/optimized predicate of single
5749 */
5750 static BmpCharPredicate Single(int c) {
5751 return ch -> ch == c;
5752 }
5753
5754 /**
5755 * Case insensitive matches a given BMP character
5756 */
5757 static BmpCharPredicate SingleI(int lower, int upper) {
5758 return ch -> ch == lower || ch == upper;
5759 }
5760
5761 /**
5762 * Unicode case insensitive matches a given Unicode character
5763 */
5764 static CharPredicate SingleU(int lower) {
5765 return ch -> lower == ch ||
5766 lower == Character.toLowerCase(Character.toUpperCase(ch));
5767 }
5768
5769 private static boolean inRange(int lower, int ch, int upper) {
5770 return lower <= ch && ch <= upper;
5771 }
5772
5773 /**
5774 * Charactrs within a explicit value range
5775 */
5776 static CharPredicate Range(int lower, int upper) {
5777 if (upper < Character.MIN_HIGH_SURROGATE ||
5778 lower > Character.MAX_HIGH_SURROGATE &&
5779 upper < Character.MIN_SUPPLEMENTARY_CODE_POINT)
5780 return (BmpCharPredicate)(ch -> inRange(lower, ch, upper));
5781 return ch -> inRange(lower, ch, upper);
5782 }
5783
5784 /**
5785 * Charactrs within a explicit value range in a case insensitive manner.
5786 */
5787 static CharPredicate CIRange(int lower, int upper) {
5788 return ch -> inRange(lower, ch, upper) ||
5789 ASCII.isAscii(ch) &&
5790 (inRange(lower, ASCII.toUpper(ch), upper) ||
5791 inRange(lower, ASCII.toLower(ch), upper));
5792 }
5793
5794 static CharPredicate CIRangeU(int lower, int upper) {
5795 return ch -> {
5796 if (inRange(lower, ch, upper))
5797 return true;
5798 int up = Character.toUpperCase(ch);
5799 return inRange(lower, up, upper) ||
5800 inRange(lower, Character.toLowerCase(up), upper);
5801 };
5802 }
5803
5804 /**
5805 * This must be the very first initializer.
5806 */
5807 static final Node accept = new Node();
5808
5809 static final Node lastAccept = new LastNode();
5810
5811 /**
5812 * Creates a predicate that tests if for a given input string argument, an
5813 * input sequence, there exists a subsequence that matches this pattern.
5814 *
5815 * @apiNote
5816 * This method creates a predicate that behaves as if it creates a matcher
5817 * from the input sequence and then calls {@code find}, for example a
5818 * predicate of the form:
5819 * <pre>{@code
5820 * s -> matcher(s).find();
5821 * }</pre>
5822 *
5823 * @return The predicate which can be used for finding a match on a subsequence of a string
5824 * @since 1.8
5825 * @see Matcher#find
5826 */
5827 public Predicate<String> asPredicate() {
5828 return s -> matcher(s).find();
5829 }
5830
5831 /**
5832 * Creates a stream from the given input sequence around matches of this
5833 * pattern.
5834 *
5835 * <p> The stream returned by this method contains each substring of the
5836 * input sequence that is terminated by another subsequence that matches
5837 * this pattern or is terminated by the end of the input sequence. The
5838 * substrings in the stream are in the order in which they occur in the
5839 * input. Trailing empty strings will be discarded and not encountered in
5840 * the stream.
5841 *
5842 * <p> If this pattern does not match any subsequence of the input then
5843 * the resulting stream has just one element, namely the input sequence in
5844 * string form.
5845 *
5846 * <p> When there is a positive-width match at the beginning of the input
5847 * sequence then an empty leading substring is included at the beginning
5848 * of the stream. A zero-width match at the beginning however never produces
5849 * such empty leading substring.
5850 *
5851 * <p> If the input sequence is mutable, it must remain constant during the
5852 * execution of the terminal stream operation. Otherwise, the result of the
5853 * terminal stream operation is undefined.
5854 *
5855 * @param input
5856 * The character sequence to be split
5857 *
5858 * @return The stream of strings computed by splitting the input
5859 * around matches of this pattern
5860 * @see #split(CharSequence)
5861 * @since 1.8
5862 */
5863 public Stream<String> splitAsStream(final CharSequence input) {
5864 class MatcherIterator implements Iterator<String> {
5865 private Matcher matcher;
5866 // The start position of the next sub-sequence of input
5867 // when current == input.length there are no more elements
5868 private int current;
5869 // null if the next element, if any, needs to obtained
5870 private String nextElement;
5871 // > 0 if there are N next empty elements
5872 private int emptyElementCount;
5873
5874 public String next() {
5875 if (!hasNext())
5876 throw new NoSuchElementException();
5877
5878 if (emptyElementCount == 0) {
5879 String n = nextElement;
5880 nextElement = null;
5881 return n;
5882 } else {
5883 emptyElementCount--;
5884 return "";
5885 }
5886 }
5887
5888 public boolean hasNext() {
5889 if (matcher == null) {
5890 matcher = matcher(input);
5891 // If the input is an empty string then the result can only be a
5892 // stream of the input. Induce that by setting the empty
5893 // element count to 1
5894 emptyElementCount = input.length() == 0 ? 1 : 0;
5895 }
5896 if (nextElement != null || emptyElementCount > 0)
5897 return true;
5898
5899 if (current == input.length())
5900 return false;
5901
5902 // Consume the next matching element
5903 // Count sequence of matching empty elements
5904 while (matcher.find()) {
5905 nextElement = input.subSequence(current, matcher.start()).toString();
5906 current = matcher.end();
5907 if (!nextElement.isEmpty()) {
5908 return true;
5909 } else if (current > 0) { // no empty leading substring for zero-width
5910 // match at the beginning of the input
5911 emptyElementCount++;
5912 }
5913 }
5914
5915 // Consume last matching element
5916 nextElement = input.subSequence(current, input.length()).toString();
5917 current = input.length();
5918 if (!nextElement.isEmpty()) {
5919 return true;
5920 } else {
5921 // Ignore a terminal sequence of matching empty elements
5922 emptyElementCount = 0;
5923 nextElement = null;
5924 return false;
5925 }
5926 }
5927 }
5928 return StreamSupport.stream(Spliterators.spliteratorUnknownSize(
5929 new MatcherIterator(), Spliterator.ORDERED | Spliterator.NONNULL), false);
5930 }
5931 }