1 /*
2 * Copyright (c) 1999, 2016, 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>
83 * <caption style="display:none">Regular expression constructs, and what they match</caption>
84 * <thead>
85 * <tr style="text-align:left">
86 * <th style="text-align:left" id="construct">Construct</th>
87 * <th style="text-align:left" id="matches">Matches</th>
88 * </tr>
89 * </thead>
90 * <tbody>
91 *
92 * <tr><th> </th></tr>
93 * <tr style="text-align:left"><th colspan="2" id="characters">Characters</th></tr>
94 *
95 * <tr><td style="vertical-align:top" headers="construct characters"><i>x</i></td>
96 * <td headers="matches">The character <i>x</i></td></tr>
97 * <tr><td style="vertical-align:top" headers="construct characters">{@code \\}</td>
98 * <td headers="matches">The backslash character</td></tr>
99 * <tr><td style="vertical-align:top" headers="construct characters">{@code \0}<i>n</i></td>
100 * <td headers="matches">The character with octal value {@code 0}<i>n</i>
101 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
102 * <tr><td style="vertical-align:top" headers="construct characters">{@code \0}<i>nn</i></td>
103 * <td headers="matches">The character with octal value {@code 0}<i>nn</i>
104 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
105 * <tr><td style="vertical-align:top" headers="construct characters">{@code \0}<i>mnn</i></td>
106 * <td headers="matches">The character with octal value {@code 0}<i>mnn</i>
107 * (0 {@code <=} <i>m</i> {@code <=} 3,
108 * 0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
109 * <tr><td style="vertical-align:top" headers="construct characters">{@code \x}<i>hh</i></td>
110 * <td headers="matches">The character with hexadecimal value {@code 0x}<i>hh</i></td></tr>
111 * <tr><td style="vertical-align:top" headers="construct characters"><code>\u</code><i>hhhh</i></td>
112 * <td headers="matches">The character with hexadecimal value {@code 0x}<i>hhhh</i></td></tr>
113 * <tr><td style="vertical-align:top" headers="construct characters"><code>\x</code><i>{h...h}</i></td>
114 * <td headers="matches">The character with hexadecimal value {@code 0x}<i>h...h</i>
115 * ({@link java.lang.Character#MIN_CODE_POINT Character.MIN_CODE_POINT}
116 * <= {@code 0x}<i>h...h</i> <=
117 * {@link java.lang.Character#MAX_CODE_POINT Character.MAX_CODE_POINT})</td></tr>
118 * <tr><td style="vertical-align:top" headers="construct characters"><code>\N{</code><i>name</i><code>}</code></td>
119 * <td headers="matches">The character with Unicode character name <i>'name'</i></td></tr>
120 * <tr><td style="vertical-align:top" headers="matches">{@code \t}</td>
121 * <td headers="matches">The tab character (<code>'\u0009'</code>)</td></tr>
122 * <tr><td style="vertical-align:top" headers="construct characters">{@code \n}</td>
123 * <td headers="matches">The newline (line feed) character (<code>'\u000A'</code>)</td></tr>
124 * <tr><td style="vertical-align:top" headers="construct characters">{@code \r}</td>
125 * <td headers="matches">The carriage-return character (<code>'\u000D'</code>)</td></tr>
126 * <tr><td style="vertical-align:top" headers="construct characters">{@code \f}</td>
127 * <td headers="matches">The form-feed character (<code>'\u000C'</code>)</td></tr>
128 * <tr><td style="vertical-align:top" headers="construct characters">{@code \a}</td>
129 * <td headers="matches">The alert (bell) character (<code>'\u0007'</code>)</td></tr>
130 * <tr><td style="vertical-align:top" headers="construct characters">{@code \e}</td>
131 * <td headers="matches">The escape character (<code>'\u001B'</code>)</td></tr>
132 * <tr><td style="vertical-align:top" headers="construct characters">{@code \c}<i>x</i></td>
133 * <td headers="matches">The control character corresponding to <i>x</i></td></tr>
134 *
135 * <tr><th> </th></tr>
136 * <tr style="text-align:left"><th colspan="2" id="classes">Character classes</th></tr>
137 *
138 * <tr><td style="vertical-align:top" headers="construct classes">{@code [abc]}</td>
139 * <td headers="matches">{@code a}, {@code b}, or {@code c} (simple class)</td></tr>
140 * <tr><td style="vertical-align:top" headers="construct classes">{@code [^abc]}</td>
141 * <td headers="matches">Any character except {@code a}, {@code b}, or {@code c} (negation)</td></tr>
142 * <tr><td style="vertical-align:top" headers="construct classes">{@code [a-zA-Z]}</td>
143 * <td headers="matches">{@code a} through {@code z}
144 * or {@code A} through {@code Z}, inclusive (range)</td></tr>
145 * <tr><td style="vertical-align:top" headers="construct classes">{@code [a-d[m-p]]}</td>
146 * <td headers="matches">{@code a} through {@code d},
147 * or {@code m} through {@code p}: {@code [a-dm-p]} (union)</td></tr>
148 * <tr><td style="vertical-align:top" headers="construct classes">{@code [a-z&&[def]]}</td>
149 * <td headers="matches">{@code d}, {@code e}, or {@code f} (intersection)</tr>
150 * <tr><td style="vertical-align:top" headers="construct classes">{@code [a-z&&[^bc]]}</td>
151 * <td headers="matches">{@code a} through {@code z},
152 * except for {@code b} and {@code c}: {@code [ad-z]} (subtraction)</td></tr>
153 * <tr><td style="vertical-align:top" headers="construct classes">{@code [a-z&&[^m-p]]}</td>
154 * <td headers="matches">{@code a} through {@code z},
155 * and not {@code m} through {@code p}: {@code [a-lq-z]}(subtraction)</td></tr>
156 * <tr><th> </th></tr>
157 *
158 * <tr style="text-align:left"><th colspan="2" id="predef">Predefined character classes</th></tr>
159 *
160 * <tr><td style="vertical-align:top" headers="construct predef">{@code .}</td>
161 * <td headers="matches">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
162 * <tr><td style="vertical-align:top" headers="construct predef">{@code \d}</td>
163 * <td headers="matches">A digit: {@code [0-9]}</td></tr>
164 * <tr><td style="vertical-align:top" headers="construct predef">{@code \D}</td>
165 * <td headers="matches">A non-digit: {@code [^0-9]}</td></tr>
166 * <tr><td style="vertical-align:top" headers="construct predef">{@code \h}</td>
167 * <td headers="matches">A horizontal whitespace character:
168 * <code>[ \t\xA0\u1680\u180e\u2000-\u200a\u202f\u205f\u3000]</code></td></tr>
169 * <tr><td style="vertical-align:top" headers="construct predef">{@code \H}</td>
170 * <td headers="matches">A non-horizontal whitespace character: {@code [^\h]}</td></tr>
171 * <tr><td style="vertical-align:top" headers="construct predef">{@code \s}</td>
172 * <td headers="matches">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
173 * <tr><td style="vertical-align:top" headers="construct predef">{@code \S}</td>
174 * <td headers="matches">A non-whitespace character: {@code [^\s]}</td></tr>
175 * <tr><td style="vertical-align:top" headers="construct predef">{@code \v}</td>
176 * <td headers="matches">A vertical whitespace character: <code>[\n\x0B\f\r\x85\u2028\u2029]</code>
177 * </td></tr>
178 * <tr><td style="vertical-align:top" headers="construct predef">{@code \V}</td>
179 * <td headers="matches">A non-vertical whitespace character: {@code [^\v]}</td></tr>
180 * <tr><td style="vertical-align:top" headers="construct predef">{@code \w}</td>
181 * <td headers="matches">A word character: {@code [a-zA-Z_0-9]}</td></tr>
182 * <tr><td style="vertical-align:top" headers="construct predef">{@code \W}</td>
183 * <td headers="matches">A non-word character: {@code [^\w]}</td></tr>
184 * <tr><th> </th></tr>
185 * <tr style="text-align:left"><th colspan="2" id="posix"><b>POSIX character classes (US-ASCII only)</b></th></tr>
186 *
187 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Lower}}</td>
188 * <td headers="matches">A lower-case alphabetic character: {@code [a-z]}</td></tr>
189 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Upper}}</td>
190 * <td headers="matches">An upper-case alphabetic character:{@code [A-Z]}</td></tr>
191 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{ASCII}}</td>
192 * <td headers="matches">All ASCII:{@code [\x00-\x7F]}</td></tr>
193 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Alpha}}</td>
194 * <td headers="matches">An alphabetic character:{@code [\p{Lower}\p{Upper}]}</td></tr>
195 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Digit}}</td>
196 * <td headers="matches">A decimal digit: {@code [0-9]}</td></tr>
197 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Alnum}}</td>
198 * <td headers="matches">An alphanumeric character:{@code [\p{Alpha}\p{Digit}]}</td></tr>
199 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Punct}}</td>
200 * <td headers="matches">Punctuation: One of {@code !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~}</td></tr>
201 * <!-- {@code [\!"#\$%&'\(\)\*\+,\-\./:;\<=\>\?@\[\\\]\^_`\{\|\}~]}
202 * {@code [\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]} -->
203 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Graph}}</td>
204 * <td headers="matches">A visible character: {@code [\p{Alnum}\p{Punct}]}</td></tr>
205 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Print}}</td>
206 * <td headers="matches">A printable character: {@code [\p{Graph}\x20]}</td></tr>
207 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Blank}}</td>
208 * <td headers="matches">A space or a tab: {@code [ \t]}</td></tr>
209 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Cntrl}}</td>
210 * <td headers="matches">A control character: {@code [\x00-\x1F\x7F]}</td></tr>
211 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{XDigit}}</td>
212 * <td headers="matches">A hexadecimal digit: {@code [0-9a-fA-F]}</td></tr>
213 * <tr><td style="vertical-align:top" headers="construct posix">{@code \p{Space}}</td>
214 * <td headers="matches">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
215 *
216 * <tr><th> </th></tr>
217 * <tr style="text-align:left"><th colspan="2">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr>
218 *
219 * <tr><td style="vertical-align:top">{@code \p{javaLowerCase}}</td>
220 * <td>Equivalent to java.lang.Character.isLowerCase()</td></tr>
221 * <tr><td style="vertical-align:top">{@code \p{javaUpperCase}}</td>
222 * <td>Equivalent to java.lang.Character.isUpperCase()</td></tr>
223 * <tr><td style="vertical-align:top">{@code \p{javaWhitespace}}</td>
224 * <td>Equivalent to java.lang.Character.isWhitespace()</td></tr>
225 * <tr><td style="vertical-align:top">{@code \p{javaMirrored}}</td>
226 * <td>Equivalent to java.lang.Character.isMirrored()</td></tr>
227 *
228 * <tr><th> </th></tr>
229 * <tr style="text-align:left"><th colspan="2" id="unicode">Classes for Unicode scripts, blocks, categories and binary properties</th></tr>
230 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \p{IsLatin}}</td>
231 * <td headers="matches">A Latin script character (<a href="#usc">script</a>)</td></tr>
232 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \p{InGreek}}</td>
233 * <td headers="matches">A character in the Greek block (<a href="#ubc">block</a>)</td></tr>
234 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \p{Lu}}</td>
235 * <td headers="matches">An uppercase letter (<a href="#ucc">category</a>)</td></tr>
236 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \p{IsAlphabetic}}</td>
237 * <td headers="matches">An alphabetic character (<a href="#ubpc">binary property</a>)</td></tr>
238 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \p{Sc}}</td>
239 * <td headers="matches">A currency symbol</td></tr>
240 * <tr><td style="vertical-align:top" headers="construct unicode">{@code \P{InGreek}}</td>
241 * <td headers="matches">Any character except one in the Greek block (negation)</td></tr>
242 * <tr><td style="vertical-align:top" headers="construct unicode">{@code [\p{L}&&[^\p{Lu}]]}</td>
243 * <td headers="matches">Any letter except an uppercase letter (subtraction)</td></tr>
244 *
245 * <tr><th> </th></tr>
246 * <tr style="text-align:left"><th colspan="2" id="bounds">Boundary matchers</th></tr>
247 *
248 * <tr><td style="vertical-align:top" headers="construct bounds">{@code ^}</td>
249 * <td headers="matches">The beginning of a line</td></tr>
250 * <tr><td style="vertical-align:top" headers="construct bounds">{@code $}</td>
251 * <td headers="matches">The end of a line</td></tr>
252 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \b}</td>
253 * <td headers="matches">A word boundary</td></tr>
254 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \b{g}}</td>
255 * <td headers="matches">A Unicode extended grapheme cluster boundary</td></tr>
256 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \B}</td>
257 * <td headers="matches">A non-word boundary</td></tr>
258 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \A}</td>
259 * <td headers="matches">The beginning of the input</td></tr>
260 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \G}</td>
261 * <td headers="matches">The end of the previous match</td></tr>
262 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \Z}</td>
263 * <td headers="matches">The end of the input but for the final
264 * <a href="#lt">terminator</a>, if any</td></tr>
265 * <tr><td style="vertical-align:top" headers="construct bounds">{@code \z}</td>
266 * <td headers="matches">The end of the input</td></tr>
267 *
268 * <tr><th> </th></tr>
269 * <tr style="text-align:left"><th colspan="2" id="lineending">Linebreak matcher</th></tr>
270 * <tr><td style="vertical-align:top" headers="construct lineending">{@code \R}</td>
271 * <td headers="matches">Any Unicode linebreak sequence, is equivalent to
272 * <code>\u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029]
273 * </code></td></tr>
274 *
275 * <tr><th> </th></tr>
276 * <tr style="text-align:left"><th colspan="2" id="grapheme">Unicode Extended Grapheme matcher</th></tr>
277 * <tr><td style="vertical-align:top" headers="construct grapheme">{@code \X}</td>
278 * <td headers="matches">Any Unicode extended grapheme cluster</td></tr>
279 *
280 * <tr><th> </th></tr>
281 * <tr style="text-align:left"><th colspan="2" id="greedy">Greedy quantifiers</th></tr>
282 *
283 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i>{@code ?}</td>
284 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
285 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i>{@code *}</td>
286 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
287 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i>{@code +}</td>
288 * <td headers="matches"><i>X</i>, one or more times</td></tr>
289 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i><code>{</code><i>n</i><code>}</code></td>
290 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
291 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i><code>{</code><i>n</i>{@code ,}}</td>
292 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
293 * <tr><td style="vertical-align:top" headers="construct greedy"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}</code></td>
294 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
295 *
296 * <tr><th> </th></tr>
297 * <tr style="text-align:left"><th colspan="2" id="reluc">Reluctant quantifiers</th></tr>
298 *
299 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i>{@code ??}</td>
300 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
301 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i>{@code *?}</td>
302 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
303 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i>{@code +?}</td>
304 * <td headers="matches"><i>X</i>, one or more times</td></tr>
305 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i><code>{</code><i>n</i><code>}?</code></td>
306 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
307 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i><code>{</code><i>n</i><code>,}?</code></td>
308 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
309 * <tr><td style="vertical-align:top" headers="construct reluc"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}?</code></td>
310 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
311 *
312 * <tr><th> </th></tr>
313 * <tr style="text-align:left"><th colspan="2" id="poss">Possessive quantifiers</th></tr>
314 *
315 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i>{@code ?+}</td>
316 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
317 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i>{@code *+}</td>
318 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
319 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i>{@code ++}</td>
320 * <td headers="matches"><i>X</i>, one or more times</td></tr>
321 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i><code>{</code><i>n</i><code>}+</code></td>
322 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
323 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i><code>{</code><i>n</i><code>,}+</code></td>
324 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
325 * <tr><td style="vertical-align:top" headers="construct poss"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}+</code></td>
326 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
327 *
328 * <tr><th> </th></tr>
329 * <tr style="text-align:left"><th colspan="2" id="logical">Logical operators</th></tr>
330 *
331 * <tr><td style="vertical-align:top" headers="construct logical"><i>XY</i></td>
332 * <td headers="matches"><i>X</i> followed by <i>Y</i></td></tr>
333 * <tr><td style="vertical-align:top" headers="construct logical"><i>X</i>{@code |}<i>Y</i></td>
334 * <td headers="matches">Either <i>X</i> or <i>Y</i></td></tr>
335 * <tr><td style="vertical-align:top" headers="construct logical">{@code (}<i>X</i>{@code )}</td>
336 * <td headers="matches">X, as a <a href="#cg">capturing group</a></td></tr>
337 *
338 * <tr><th> </th></tr>
339 * <tr style="text-align:left"><th colspan="2" id="backref">Back references</th></tr>
340 *
341 * <tr><td style="vertical-align:bottom" headers="construct backref">{@code \}<i>n</i></td>
342 * <td style="vertical-align:bottom" headers="matches">Whatever the <i>n</i><sup>th</sup>
343 * <a href="#cg">capturing group</a> matched</td></tr>
344 *
345 * <tr><td style="vertical-align:bottom" headers="construct backref">{@code \}<i>k</i><<i>name</i>></td>
346 * <td style="vertical-align:bottom" headers="matches">Whatever the
347 * <a href="#groupname">named-capturing group</a> "name" matched</td></tr>
348 *
349 * <tr><th> </th></tr>
350 * <tr style="text-align:left"><th colspan="2" id="quot">Quotation</th></tr>
351 *
352 * <tr><td style="vertical-align:top" headers="construct quot">{@code \}</td>
353 * <td headers="matches">Nothing, but quotes the following character</td></tr>
354 * <tr><td style="vertical-align:top" headers="construct quot">{@code \Q}</td>
355 * <td headers="matches">Nothing, but quotes all characters until {@code \E}</td></tr>
356 * <tr><td style="vertical-align:top" headers="construct quot">{@code \E}</td>
357 * <td headers="matches">Nothing, but ends quoting started by {@code \Q}</td></tr>
358 * <!-- Metachars: !$()*+.<>?[\]^{|} -->
359 *
360 * <tr><th> </th></tr>
361 * <tr style="text-align:left"><th colspan="2" id="special">Special constructs (named-capturing and non-capturing)</th></tr>
362 *
363 * <tr><td style="vertical-align:top" headers="construct special"><code>(?<<a href="#groupname">name</a>></code><i>X</i>{@code )}</td>
364 * <td headers="matches"><i>X</i>, as a named-capturing group</td></tr>
365 * <tr><td style="vertical-align:top" headers="construct special">{@code (?:}<i>X</i>{@code )}</td>
366 * <td headers="matches"><i>X</i>, as a non-capturing group</td></tr>
367 * <tr><td style="vertical-align:top" headers="construct special"><code>(?idmsuxU-idmsuxU) </code></td>
368 * <td headers="matches">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a>
369 * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a>
370 * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> <a href="#UNICODE_CHARACTER_CLASS">U</a>
371 * on - off</td></tr>
372 * <tr><td style="vertical-align:top" headers="construct special"><code>(?idmsux-idmsux:</code><i>X</i>{@code )} </td>
373 * <td headers="matches"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the
374 * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a>
375 * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a >
376 * <a href="#COMMENTS">x</a> on - off</td></tr>
377 * <tr><td style="vertical-align:top" headers="construct special">{@code (?=}<i>X</i>{@code )}</td>
378 * <td headers="matches"><i>X</i>, via zero-width positive lookahead</td></tr>
379 * <tr><td style="vertical-align:top" headers="construct special">{@code (?!}<i>X</i>{@code )}</td>
380 * <td headers="matches"><i>X</i>, via zero-width negative lookahead</td></tr>
381 * <tr><td style="vertical-align:top" headers="construct special">{@code (?<=}<i>X</i>{@code )}</td>
382 * <td headers="matches"><i>X</i>, via zero-width positive lookbehind</td></tr>
383 * <tr><td style="vertical-align:top" headers="construct special">{@code (?<!}<i>X</i>{@code )}</td>
384 * <td headers="matches"><i>X</i>, via zero-width negative lookbehind</td></tr>
385 * <tr><td style="vertical-align:top" headers="construct special">{@code (?>}<i>X</i>{@code )}</td>
386 * <td headers="matches"><i>X</i>, as an independent, non-capturing group</td></tr>
387 *
388 * </tbody>
389 * </table>
390 *
391 * <hr>
392 *
393 *
394 * <h3><a id="bs">Backslashes, escapes, and quoting</a></h3>
395 *
396 * <p> The backslash character ({@code '\'}) serves to introduce escaped
397 * constructs, as defined in the table above, as well as to quote characters
398 * that otherwise would be interpreted as unescaped constructs. Thus the
399 * expression {@code \\} matches a single backslash and <code>\{</code> matches a
400 * left brace.
401 *
402 * <p> It is an error to use a backslash prior to any alphabetic character that
403 * does not denote an escaped construct; these are reserved for future
404 * extensions to the regular-expression language. A backslash may be used
405 * prior to a non-alphabetic character regardless of whether that character is
406 * part of an unescaped construct.
407 *
408 * <p> Backslashes within string literals in Java source code are interpreted
409 * as required by
410 * <cite>The Java™ Language Specification</cite>
411 * as either Unicode escapes (section 3.3) or other character escapes (section 3.10.6)
412 * It is therefore necessary to double backslashes in string
413 * literals that represent regular expressions to protect them from
414 * interpretation by the Java bytecode compiler. The string literal
415 * <code>"\b"</code>, for example, matches a single backspace character when
416 * interpreted as a regular expression, while {@code "\\b"} matches a
417 * word boundary. The string literal {@code "\(hello\)"} is illegal
418 * and leads to a compile-time error; in order to match the string
419 * {@code (hello)} the string literal {@code "\\(hello\\)"}
420 * must be used.
421 *
422 * <h3><a id="cc">Character Classes</a></h3>
423 *
424 * <p> Character classes may appear within other character classes, and
425 * may be composed by the union operator (implicit) and the intersection
426 * operator ({@code &&}).
427 * The union operator denotes a class that contains every character that is
428 * in at least one of its operand classes. The intersection operator
429 * denotes a class that contains every character that is in both of its
430 * operand classes.
431 *
432 * <p> The precedence of character-class operators is as follows, from
433 * highest to lowest:
434 *
435 * <blockquote><table>
436 * <caption style="display:none">Precedence of character class operators.</caption>
437 * <tbody>
438 * <tr><th>1 </th>
439 * <td>Literal escape </td>
440 * <td>{@code \x}</td></tr>
441 * <tr><th>2 </th>
442 * <td>Grouping</td>
443 * <td>{@code [...]}</td></tr>
444 * <tr><th>3 </th>
445 * <td>Range</td>
446 * <td>{@code a-z}</td></tr>
447 * <tr><th>4 </th>
448 * <td>Union</td>
449 * <td>{@code [a-e][i-u]}</td></tr>
450 * <tr><th>5 </th>
451 * <td>Intersection</td>
452 * <td>{@code [a-z&&[aeiou]]}</td></tr>
453 * </tbody>
454 * </table></blockquote>
455 *
456 * <p> Note that a different set of metacharacters are in effect inside
457 * a character class than outside a character class. For instance, the
458 * regular expression {@code .} loses its special meaning inside a
459 * character class, while the expression {@code -} becomes a range
460 * forming metacharacter.
461 *
462 * <h3><a id="lt">Line terminators</a></h3>
463 *
464 * <p> A <i>line terminator</i> is a one- or two-character sequence that marks
465 * the end of a line of the input character sequence. The following are
466 * recognized as line terminators:
467 *
468 * <ul>
469 *
470 * <li> A newline (line feed) character ({@code '\n'}),
471 *
472 * <li> A carriage-return character followed immediately by a newline
473 * character ({@code "\r\n"}),
474 *
475 * <li> A standalone carriage-return character ({@code '\r'}),
476 *
477 * <li> A next-line character (<code>'\u0085'</code>),
478 *
479 * <li> A line-separator character (<code>'\u2028'</code>), or
480 *
481 * <li> A paragraph-separator character (<code>'\u2029'</code>).
482 *
483 * </ul>
484 * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators
485 * recognized are newline characters.
486 *
487 * <p> The regular expression {@code .} matches any character except a line
488 * terminator unless the {@link #DOTALL} flag is specified.
489 *
490 * <p> By default, the regular expressions {@code ^} and {@code $} ignore
491 * line terminators and only match at the beginning and the end, respectively,
492 * of the entire input sequence. If {@link #MULTILINE} mode is activated then
493 * {@code ^} matches at the beginning of input and after any line terminator
494 * except at the end of input. When in {@link #MULTILINE} mode {@code $}
495 * matches just before a line terminator or the end of the input sequence.
496 *
497 * <h3><a id="cg">Groups and capturing</a></h3>
498 *
499 * <h4><a id="gnumber">Group number</a></h4>
500 * <p> Capturing groups are numbered by counting their opening parentheses from
501 * left to right. In the expression {@code ((A)(B(C)))}, for example, there
502 * are four such groups: </p>
503 *
504 * <blockquote><table>
505 * <caption style="display:none">Capturing group numberings</caption>
506 * <tbody>
507 * <tr><th>1 </th>
508 * <td>{@code ((A)(B(C)))}</td></tr>
509 * <tr><th>2 </th>
510 * <td>{@code (A)}</td></tr>
511 * <tr><th>3 </th>
512 * <td>{@code (B(C))}</td></tr>
513 * <tr><th>4 </th>
514 * <td>{@code (C)}</td></tr>
515 * </tbody>
516 * </table></blockquote>
517 *
518 * <p> Group zero always stands for the entire expression.
519 *
520 * <p> Capturing groups are so named because, during a match, each subsequence
521 * of the input sequence that matches such a group is saved. The captured
522 * subsequence may be used later in the expression, via a back reference, and
523 * may also be retrieved from the matcher once the match operation is complete.
524 *
525 * <h4><a id="groupname">Group name</a></h4>
526 * <p>A capturing group can also be assigned a "name", a {@code named-capturing group},
527 * and then be back-referenced later by the "name". Group names are composed of
528 * the following characters. The first character must be a {@code letter}.
529 *
530 * <ul>
531 * <li> The uppercase letters {@code 'A'} through {@code 'Z'}
532 * (<code>'\u0041'</code> through <code>'\u005a'</code>),
533 * <li> The lowercase letters {@code 'a'} through {@code 'z'}
534 * (<code>'\u0061'</code> through <code>'\u007a'</code>),
535 * <li> The digits {@code '0'} through {@code '9'}
536 * (<code>'\u0030'</code> through <code>'\u0039'</code>),
537 * </ul>
538 *
539 * <p> A {@code named-capturing group} is still numbered as described in
540 * <a href="#gnumber">Group number</a>.
541 *
542 * <p> The captured input associated with a group is always the subsequence
543 * that the group most recently matched. If a group is evaluated a second time
544 * because of quantification then its previously-captured value, if any, will
545 * be retained if the second evaluation fails. Matching the string
546 * {@code "aba"} against the expression {@code (a(b)?)+}, for example, leaves
547 * group two set to {@code "b"}. All captured input is discarded at the
548 * beginning of each match.
549 *
550 * <p> Groups beginning with {@code (?} are either pure, <i>non-capturing</i> groups
551 * that do not capture text and do not count towards the group total, or
552 * <i>named-capturing</i> group.
553 *
554 * <h3> Unicode support </h3>
555 *
556 * <p> This class is in conformance with Level 1 of <a
557 * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
558 * Standard #18: Unicode Regular Expression</i></a>, plus RL2.1
559 * Canonical Equivalents.
560 * <p>
561 * <b>Unicode escape sequences</b> such as <code>\u2014</code> in Java source code
562 * are processed as described in section 3.3 of
563 * <cite>The Java™ Language Specification</cite>.
564 * Such escape sequences are also implemented directly by the regular-expression
565 * parser so that Unicode escapes can be used in expressions that are read from
566 * files or from the keyboard. Thus the strings <code>"\u2014"</code> and
567 * {@code "\\u2014"}, while not equal, compile into the same pattern, which
568 * matches the character with hexadecimal value {@code 0x2014}.
569 * <p>
570 * A Unicode character can also be represented by using its <b>Hex notation</b>
571 * (hexadecimal code point value) directly as described in construct
572 * <code>\x{...}</code>, for example a supplementary character U+2011F can be
573 * specified as <code>\x{2011F}</code>, instead of two consecutive Unicode escape
574 * sequences of the surrogate pair <code>\uD840</code><code>\uDD1F</code>.
575 * <p>
576 * <b>Unicode character names</b> are supported by the named character construct
577 * <code>\N{</code>...<code>}</code>, for example, <code>\N{WHITE SMILING FACE}</code>
578 * specifies character <code>\u263A</code>. The character names supported
579 * by this class are the valid Unicode character names matched by
580 * {@link java.lang.Character#codePointOf(String) Character.codePointOf(name)}.
581 * <p>
582 * <a href="http://www.unicode.org/reports/tr18/#Default_Grapheme_Clusters">
583 * <b>Unicode extended grapheme clusters</b></a> are supported by the grapheme
584 * cluster matcher {@code \X} and the corresponding boundary matcher {@code \b{g}}.
585 * <p>
586 * Unicode scripts, blocks, categories and binary properties are written with
587 * the {@code \p} and {@code \P} constructs as in Perl.
588 * <code>\p{</code><i>prop</i><code>}</code> matches if
589 * the input has the property <i>prop</i>, while <code>\P{</code><i>prop</i><code>}</code>
590 * does not match if the input has that property.
591 * <p>
592 * Scripts, blocks, categories and binary properties can be used both inside
593 * and outside of a character class.
594 *
595 * <p>
596 * <b><a id="usc">Scripts</a></b> are specified either with the prefix {@code Is}, as in
597 * {@code IsHiragana}, or by using the {@code script} keyword (or its short
598 * form {@code sc}) as in {@code script=Hiragana} or {@code sc=Hiragana}.
599 * <p>
600 * The script names supported by {@code Pattern} are the valid script names
601 * accepted and defined by
602 * {@link java.lang.Character.UnicodeScript#forName(String) UnicodeScript.forName}.
603 *
604 * <p>
605 * <b><a id="ubc">Blocks</a></b> are specified with the prefix {@code In}, as in
606 * {@code InMongolian}, or by using the keyword {@code block} (or its short
607 * form {@code blk}) as in {@code block=Mongolian} or {@code blk=Mongolian}.
608 * <p>
609 * The block names supported by {@code Pattern} are the valid block names
610 * accepted and defined by
611 * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}.
612 * <p>
613 *
614 * <b><a id="ucc">Categories</a></b> may be specified with the optional prefix {@code Is}:
615 * Both {@code \p{L}} and {@code \p{IsL}} denote the category of Unicode
616 * letters. Same as scripts and blocks, categories can also be specified
617 * by using the keyword {@code general_category} (or its short form
618 * {@code gc}) as in {@code general_category=Lu} or {@code gc=Lu}.
619 * <p>
620 * The supported categories are those of
621 * <a href="http://www.unicode.org/unicode/standard/standard.html">
622 * <i>The Unicode Standard</i></a> in the version specified by the
623 * {@link java.lang.Character Character} class. The category names are those
624 * defined in the Standard, both normative and informative.
625 * <p>
626 *
627 * <b><a id="ubpc">Binary properties</a></b> are specified with the prefix {@code Is}, as in
628 * {@code IsAlphabetic}. The supported binary properties by {@code Pattern}
629 * are
630 * <ul>
631 * <li> Alphabetic
632 * <li> Ideographic
633 * <li> Letter
634 * <li> Lowercase
635 * <li> Uppercase
636 * <li> Titlecase
637 * <li> Punctuation
638 * <Li> Control
639 * <li> White_Space
640 * <li> Digit
641 * <li> Hex_Digit
642 * <li> Join_Control
643 * <li> Noncharacter_Code_Point
644 * <li> Assigned
645 * </ul>
646 * <p>
647 * The following <b>Predefined Character classes</b> and <b>POSIX character classes</b>
648 * are in conformance with the recommendation of <i>Annex C: Compatibility Properties</i>
649 * of <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Regular Expression
650 * </i></a>, when {@link #UNICODE_CHARACTER_CLASS} flag is specified.
651 *
652 * <table>
653 * <caption style="display:none">predefined and posix character classes in Unicode mode</caption>
654 * <thead>
655 * <tr style="text-align:left">
656 * <th style="text-align:left" id="predef_classes">Classes</th>
657 * <th style="text-align:left" id="predef_matches">Matches</th>
658 * </tr>
659 * </thead>
660 * <tbody>
661 * <tr><td>{@code \p{Lower}}</td>
662 * <td>A lowercase character:{@code \p{IsLowercase}}</td></tr>
663 * <tr><td>{@code \p{Upper}}</td>
664 * <td>An uppercase character:{@code \p{IsUppercase}}</td></tr>
665 * <tr><td>{@code \p{ASCII}}</td>
666 * <td>All ASCII:{@code [\x00-\x7F]}</td></tr>
667 * <tr><td>{@code \p{Alpha}}</td>
668 * <td>An alphabetic character:{@code \p{IsAlphabetic}}</td></tr>
669 * <tr><td>{@code \p{Digit}}</td>
670 * <td>A decimal digit character:{@code p{IsDigit}}</td></tr>
671 * <tr><td>{@code \p{Alnum}}</td>
672 * <td>An alphanumeric character:{@code [\p{IsAlphabetic}\p{IsDigit}]}</td></tr>
673 * <tr><td>{@code \p{Punct}}</td>
674 * <td>A punctuation character:{@code p{IsPunctuation}}</td></tr>
675 * <tr><td>{@code \p{Graph}}</td>
676 * <td>A visible character: {@code [^\p{IsWhite_Space}\p{gc=Cc}\p{gc=Cs}\p{gc=Cn}]}</td></tr>
677 * <tr><td>{@code \p{Print}}</td>
678 * <td>A printable character: {@code [\p{Graph}\p{Blank}&&[^\p{Cntrl}]]}</td></tr>
679 * <tr><td>{@code \p{Blank}}</td>
680 * <td>A space or a tab: {@code [\p{IsWhite_Space}&&[^\p{gc=Zl}\p{gc=Zp}\x0a\x0b\x0c\x0d\x85]]}</td></tr>
681 * <tr><td>{@code \p{Cntrl}}</td>
682 * <td>A control character: {@code \p{gc=Cc}}</td></tr>
683 * <tr><td>{@code \p{XDigit}}</td>
684 * <td>A hexadecimal digit: {@code [\p{gc=Nd}\p{IsHex_Digit}]}</td></tr>
685 * <tr><td>{@code \p{Space}}</td>
686 * <td>A whitespace character:{@code \p{IsWhite_Space}}</td></tr>
687 * <tr><td>{@code \d}</td>
688 * <td>A digit: {@code \p{IsDigit}}</td></tr>
689 * <tr><td>{@code \D}</td>
690 * <td>A non-digit: {@code [^\d]}</td></tr>
691 * <tr><td>{@code \s}</td>
692 * <td>A whitespace character: {@code \p{IsWhite_Space}}</td></tr>
693 * <tr><td>{@code \S}</td>
694 * <td>A non-whitespace character: {@code [^\s]}</td></tr>
695 * <tr><td>{@code \w}</td>
696 * <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>
697 * <tr><td>{@code \W}</td>
698 * <td>A non-word character: {@code [^\w]}</td></tr>
699 * </tbody>
700 * </table>
701 * <p>
702 * <a id="jcc">
703 * Categories that behave like the java.lang.Character
704 * boolean is<i>methodname</i> methods (except for the deprecated ones) are
705 * available through the same <code>\p{</code><i>prop</i><code>}</code> syntax where
706 * the specified property has the name <code>java<i>methodname</i></code></a>.
707 *
708 * <h3> Comparison to Perl 5 </h3>
709 *
710 * <p>The {@code Pattern} engine performs traditional NFA-based matching
711 * with ordered alternation as occurs in Perl 5.
712 *
713 * <p> Perl constructs not supported by this class: </p>
714 *
715 * <ul>
716 * <li><p> The backreference constructs, <code>\g{</code><i>n</i><code>}</code> for
717 * the <i>n</i><sup>th</sup><a href="#cg">capturing group</a> and
718 * <code>\g{</code><i>name</i><code>}</code> for
719 * <a href="#groupname">named-capturing group</a>.
720 * </p></li>
721 *
722 * <li><p> The conditional constructs
723 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code )} and
724 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code |}<i>Y</i>{@code )},
725 * </p></li>
726 *
727 * <li><p> The embedded code constructs <code>(?{</code><i>code</i><code>})</code>
728 * and <code>(??{</code><i>code</i><code>})</code>,</p></li>
729 *
730 * <li><p> The embedded comment syntax {@code (?#comment)}, and </p></li>
731 *
732 * <li><p> The preprocessing operations {@code \l} <code>\u</code>,
733 * {@code \L}, and {@code \U}. </p></li>
734 *
735 * </ul>
736 *
737 * <p> Constructs supported by this class but not by Perl: </p>
738 *
739 * <ul>
740 *
741 * <li><p> Character-class union and intersection as described
742 * <a href="#cc">above</a>.</p></li>
743 *
744 * </ul>
745 *
746 * <p> Notable differences from Perl: </p>
747 *
748 * <ul>
749 *
750 * <li><p> In Perl, {@code \1} through {@code \9} are always interpreted
751 * as back references; a backslash-escaped number greater than {@code 9} is
752 * treated as a back reference if at least that many subexpressions exist,
753 * otherwise it is interpreted, if possible, as an octal escape. In this
754 * class octal escapes must always begin with a zero. In this class,
755 * {@code \1} through {@code \9} are always interpreted as back
756 * references, and a larger number is accepted as a back reference if at
757 * least that many subexpressions exist at that point in the regular
758 * expression, otherwise the parser will drop digits until the number is
759 * smaller or equal to the existing number of groups or it is one digit.
760 * </p></li>
761 *
762 * <li><p> Perl uses the {@code g} flag to request a match that resumes
763 * where the last match left off. This functionality is provided implicitly
764 * by the {@link Matcher} class: Repeated invocations of the {@link
765 * Matcher#find find} method will resume where the last match left off,
766 * unless the matcher is reset. </p></li>
767 *
768 * <li><p> In Perl, embedded flags at the top level of an expression affect
769 * the whole expression. In this class, embedded flags always take effect
770 * at the point at which they appear, whether they are at the top level or
771 * within a group; in the latter case, flags are restored at the end of the
772 * group just as in Perl. </p></li>
773 *
774 * </ul>
775 *
776 *
777 * <p> For a more precise description of the behavior of regular expression
778 * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/">
779 * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl,
780 * O'Reilly and Associates, 2006.</a>
781 * </p>
782 *
783 * @see java.lang.String#split(String, int)
784 * @see java.lang.String#split(String)
785 *
786 * @author Mike McCloskey
787 * @author Mark Reinhold
788 * @author JSR-51 Expert Group
789 * @since 1.4
790 * @spec JSR-51
791 */
792
793 public final class Pattern
794 implements java.io.Serializable
795 {
796
797 /**
798 * Regular expression modifier values. Instead of being passed as
799 * arguments, they can also be passed as inline modifiers.
800 * For example, the following statements have the same effect.
801 * <pre>
802 * RegExp r1 = RegExp.compile("abc", Pattern.I|Pattern.M);
803 * RegExp r2 = RegExp.compile("(?im)abc", 0);
804 * </pre>
805 *
806 * The flags are duplicated so that the familiar Perl match flag
807 * names are available.
808 */
809
810 /**
811 * Enables Unix lines mode.
812 *
813 * <p> In this mode, only the {@code '\n'} line terminator is recognized
814 * in the behavior of {@code .}, {@code ^}, and {@code $}.
815 *
816 * <p> Unix lines mode can also be enabled via the embedded flag
817 * expression {@code (?d)}.
818 */
819 public static final int UNIX_LINES = 0x01;
820
821 /**
822 * Enables case-insensitive matching.
823 *
824 * <p> By default, case-insensitive matching assumes that only characters
825 * in the US-ASCII charset are being matched. Unicode-aware
826 * case-insensitive matching can be enabled by specifying the {@link
827 * #UNICODE_CASE} flag in conjunction with this flag.
828 *
829 * <p> Case-insensitive matching can also be enabled via the embedded flag
830 * expression {@code (?i)}.
831 *
832 * <p> Specifying this flag may impose a slight performance penalty. </p>
833 */
834 public static final int CASE_INSENSITIVE = 0x02;
835
836 /**
837 * Permits whitespace and comments in pattern.
838 *
839 * <p> In this mode, whitespace is ignored, and embedded comments starting
840 * with {@code #} are ignored until the end of a line.
841 *
842 * <p> Comments mode can also be enabled via the embedded flag
843 * expression {@code (?x)}.
844 */
845 public static final int COMMENTS = 0x04;
846
847 /**
848 * Enables multiline mode.
849 *
850 * <p> In multiline mode the expressions {@code ^} and {@code $} match
851 * just after or just before, respectively, a line terminator or the end of
852 * the input sequence. By default these expressions only match at the
853 * beginning and the end of the entire input sequence.
854 *
855 * <p> Multiline mode can also be enabled via the embedded flag
856 * expression {@code (?m)}. </p>
857 */
858 public static final int MULTILINE = 0x08;
859
860 /**
861 * Enables literal parsing of the pattern.
862 *
863 * <p> When this flag is specified then the input string that specifies
864 * the pattern is treated as a sequence of literal characters.
865 * Metacharacters or escape sequences in the input sequence will be
866 * given no special meaning.
867 *
868 * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on
869 * matching when used in conjunction with this flag. The other flags
870 * become superfluous.
871 *
872 * <p> There is no embedded flag character for enabling literal parsing.
873 * @since 1.5
874 */
875 public static final int LITERAL = 0x10;
876
877 /**
878 * Enables dotall mode.
879 *
880 * <p> In dotall mode, the expression {@code .} matches any character,
881 * including a line terminator. By default this expression does not match
882 * line terminators.
883 *
884 * <p> Dotall mode can also be enabled via the embedded flag
885 * expression {@code (?s)}. (The {@code s} is a mnemonic for
886 * "single-line" mode, which is what this is called in Perl.) </p>
887 */
888 public static final int DOTALL = 0x20;
889
890 /**
891 * Enables Unicode-aware case folding.
892 *
893 * <p> When this flag is specified then case-insensitive matching, when
894 * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner
895 * consistent with the Unicode Standard. By default, case-insensitive
896 * matching assumes that only characters in the US-ASCII charset are being
897 * matched.
898 *
899 * <p> Unicode-aware case folding can also be enabled via the embedded flag
900 * expression {@code (?u)}.
901 *
902 * <p> Specifying this flag may impose a performance penalty. </p>
903 */
904 public static final int UNICODE_CASE = 0x40;
905
906 /**
907 * Enables canonical equivalence.
908 *
909 * <p> When this flag is specified then two characters will be considered
910 * to match if, and only if, their full canonical decompositions match.
911 * The expression <code>"a\u030A"</code>, for example, will match the
912 * string <code>"\u00E5"</code> when this flag is specified. By default,
913 * matching does not take canonical equivalence into account.
914 *
915 * <p> There is no embedded flag character for enabling canonical
916 * equivalence.
917 *
918 * <p> Specifying this flag may impose a performance penalty. </p>
919 */
920 public static final int CANON_EQ = 0x80;
921
922 /**
923 * Enables the Unicode version of <i>Predefined character classes</i> and
924 * <i>POSIX character classes</i>.
925 *
926 * <p> When this flag is specified then the (US-ASCII only)
927 * <i>Predefined character classes</i> and <i>POSIX character classes</i>
928 * are in conformance with
929 * <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
930 * Standard #18: Unicode Regular Expression</i></a>
931 * <i>Annex C: Compatibility Properties</i>.
932 * <p>
933 * The UNICODE_CHARACTER_CLASS mode can also be enabled via the embedded
934 * flag expression {@code (?U)}.
935 * <p>
936 * The flag implies UNICODE_CASE, that is, it enables Unicode-aware case
937 * folding.
938 * <p>
939 * Specifying this flag may impose a performance penalty. </p>
940 * @since 1.7
941 */
942 public static final int UNICODE_CHARACTER_CLASS = 0x100;
943
944 /**
945 * Contains all possible flags for compile(regex, flags).
946 */
947 private static final int ALL_FLAGS = CASE_INSENSITIVE | MULTILINE |
948 DOTALL | UNICODE_CASE | CANON_EQ | UNIX_LINES | LITERAL |
949 UNICODE_CHARACTER_CLASS | COMMENTS;
950
951 /* Pattern has only two serialized components: The pattern string
952 * and the flags, which are all that is needed to recompile the pattern
953 * when it is deserialized.
954 */
955
956 /** use serialVersionUID from Merlin b59 for interoperability */
957 private static final long serialVersionUID = 5073258162644648461L;
958
959 /**
960 * The original regular-expression pattern string.
961 *
962 * @serial
963 */
964 private String pattern;
965
966 /**
967 * The original pattern flags.
968 *
969 * @serial
970 */
971 private int flags;
972
973 /**
974 * Boolean indicating this Pattern is compiled; this is necessary in order
975 * to lazily compile deserialized Patterns.
976 */
977 private transient volatile boolean compiled;
978
979 /**
980 * The normalized pattern string.
981 */
982 private transient String normalizedPattern;
983
984 /**
985 * The starting point of state machine for the find operation. This allows
986 * a match to start anywhere in the input.
987 */
988 transient Node root;
989
990 /**
991 * The root of object tree for a match operation. The pattern is matched
992 * at the beginning. This may include a find that uses BnM or a First
993 * node.
994 */
995 transient Node matchRoot;
996
997 /**
998 * Temporary storage used by parsing pattern slice.
999 */
1000 transient int[] buffer;
1001
1002 /**
1003 * A temporary storage used for predicate for double return.
1004 */
1005 transient CharPredicate predicate;
1006
1007 /**
1008 * Map the "name" of the "named capturing group" to its group id
1009 * node.
1010 */
1011 transient volatile Map<String, Integer> namedGroups;
1012
1013 /**
1014 * Temporary storage used while parsing group references.
1015 */
1016 transient GroupHead[] groupNodes;
1017
1018 /**
1019 * Temporary storage used to store the top level closure nodes.
1020 */
1021 transient List<Node> topClosureNodes;
1022
1023 /**
1024 * The number of top greedy closure nodes in this Pattern. Used by
1025 * matchers to allocate storage needed for a IntHashSet to keep the
1026 * beginning pos {@code i} of all failed match.
1027 */
1028 transient int localTCNCount;
1029
1030 /*
1031 * Turn off the stop-exponential-backtracking optimization if there
1032 * is a group ref in the pattern.
1033 */
1034 transient boolean hasGroupRef;
1035
1036 /**
1037 * Temporary null terminated code point array used by pattern compiling.
1038 */
1039 private transient int[] temp;
1040
1041 /**
1042 * The number of capturing groups in this Pattern. Used by matchers to
1043 * allocate storage needed to perform a match.
1044 */
1045 transient int capturingGroupCount;
1046
1047 /**
1048 * The local variable count used by parsing tree. Used by matchers to
1049 * allocate storage needed to perform a match.
1050 */
1051 transient int localCount;
1052
1053 /**
1054 * Index into the pattern string that keeps track of how much has been
1055 * parsed.
1056 */
1057 private transient int cursor;
1058
1059 /**
1060 * Holds the length of the pattern string.
1061 */
1062 private transient int patternLength;
1063
1064 /**
1065 * If the Start node might possibly match supplementary characters.
1066 * It is set to true during compiling if
1067 * (1) There is supplementary char in pattern, or
1068 * (2) There is complement node of a "family" CharProperty
1069 */
1070 private transient boolean hasSupplementary;
1071
1072 /**
1073 * Compiles the given regular expression into a pattern.
1074 *
1075 * @param regex
1076 * The expression to be compiled
1077 * @return the given regular expression compiled into a pattern
1078 * @throws PatternSyntaxException
1079 * If the expression's syntax is invalid
1080 */
1081 public static Pattern compile(String regex) {
1082 return new Pattern(regex, 0);
1083 }
1084
1085 /**
1086 * Compiles the given regular expression into a pattern with the given
1087 * flags.
1088 *
1089 * @param regex
1090 * The expression to be compiled
1091 *
1092 * @param flags
1093 * Match flags, a bit mask that may include
1094 * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
1095 * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
1096 * {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS}
1097 * and {@link #COMMENTS}
1098 *
1099 * @return the given regular expression compiled into a pattern with the given flags
1100 * @throws IllegalArgumentException
1101 * If bit values other than those corresponding to the defined
1102 * match flags are set in {@code flags}
1103 *
1104 * @throws PatternSyntaxException
1105 * If the expression's syntax is invalid
1106 */
1107 public static Pattern compile(String regex, int flags) {
1108 return new Pattern(regex, flags);
1109 }
1110
1111 /**
1112 * Returns the regular expression from which this pattern was compiled.
1113 *
1114 * @return The source of this pattern
1115 */
1116 public String pattern() {
1117 return pattern;
1118 }
1119
1120 /**
1121 * <p>Returns the string representation of this pattern. This
1122 * is the regular expression from which this pattern was
1123 * compiled.</p>
1124 *
1125 * @return The string representation of this pattern
1126 * @since 1.5
1127 */
1128 public String toString() {
1129 return pattern;
1130 }
1131
1132 /**
1133 * Creates a matcher that will match the given input against this pattern.
1134 *
1135 * @param input
1136 * The character sequence to be matched
1137 *
1138 * @return A new matcher for this pattern
1139 */
1140 public Matcher matcher(CharSequence input) {
1141 if (!compiled) {
1142 synchronized(this) {
1143 if (!compiled)
1144 compile();
1145 }
1146 }
1147 Matcher m = new Matcher(this, input);
1148 return m;
1149 }
1150
1151 /**
1152 * Returns this pattern's match flags.
1153 *
1154 * @return The match flags specified when this pattern was compiled
1155 */
1156 public int flags() {
1157 return flags;
1158 }
1159
1160 /**
1161 * Compiles the given regular expression and attempts to match the given
1162 * input against it.
1163 *
1164 * <p> An invocation of this convenience method of the form
1165 *
1166 * <blockquote><pre>
1167 * Pattern.matches(regex, input);</pre></blockquote>
1168 *
1169 * behaves in exactly the same way as the expression
1170 *
1171 * <blockquote><pre>
1172 * Pattern.compile(regex).matcher(input).matches()</pre></blockquote>
1173 *
1174 * <p> If a pattern is to be used multiple times, compiling it once and reusing
1175 * it will be more efficient than invoking this method each time. </p>
1176 *
1177 * @param regex
1178 * The expression to be compiled
1179 *
1180 * @param input
1181 * The character sequence to be matched
1182 * @return whether or not the regular expression matches on the input
1183 * @throws PatternSyntaxException
1184 * If the expression's syntax is invalid
1185 */
1186 public static boolean matches(String regex, CharSequence input) {
1187 Pattern p = Pattern.compile(regex);
1188 Matcher m = p.matcher(input);
1189 return m.matches();
1190 }
1191
1192 /**
1193 * Splits the given input sequence around matches of this pattern.
1194 *
1195 * <p> The array returned by this method contains each substring of the
1196 * input sequence that is terminated by another subsequence that matches
1197 * this pattern or is terminated by the end of the input sequence. The
1198 * substrings in the array are in the order in which they occur in the
1199 * input. If this pattern does not match any subsequence of the input then
1200 * the resulting array has just one element, namely the input sequence in
1201 * string form.
1202 *
1203 * <p> When there is a positive-width match at the beginning of the input
1204 * sequence then an empty leading substring is included at the beginning
1205 * of the resulting array. A zero-width match at the beginning however
1206 * never produces such empty leading substring.
1207 *
1208 * <p> The {@code limit} parameter controls the number of times the
1209 * pattern is applied and therefore affects the length of the resulting
1210 * array. If the limit <i>n</i> is greater than zero then the pattern
1211 * will be applied at most <i>n</i> - 1 times, the array's
1212 * length will be no greater than <i>n</i>, and the array's last entry
1213 * will contain all input beyond the last matched delimiter. If <i>n</i>
1214 * is non-positive then the pattern will be applied as many times as
1215 * possible and the array can have any length. If <i>n</i> is zero then
1216 * the pattern will be applied as many times as possible, the array can
1217 * have any length, and trailing empty strings will be discarded.
1218 *
1219 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1220 * results with these parameters:
1221 *
1222 * <blockquote><table>
1223 * <caption>Split examples showing regex, limit, and result</caption>
1224 * <thead>
1225 * <tr><th style="text-align:left"><i>Regex </i></th>
1226 * <th style="text-align:left"><i>Limit </i></th>
1227 * <th style="text-align:left"><i>Result </i></th></tr>
1228 * </thead>
1229 * <tbody>
1230 * <tr><td style="text-align:center">:</td>
1231 * <td style="text-align:center">2</td>
1232 * <td>{@code { "boo", "and:foo" }}</td></tr>
1233 * <tr><td style="text-align:center">:</td>
1234 * <td style="text-align:center">5</td>
1235 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1236 * <tr><td style="text-align:center">:</td>
1237 * <td style="text-align:center">-2</td>
1238 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1239 * <tr><td style="text-align:center">o</td>
1240 * <td style="text-align:center">5</td>
1241 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1242 * <tr><td style="text-align:center">o</td>
1243 * <td style="text-align:center">-2</td>
1244 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1245 * <tr><td style="text-align:center">o</td>
1246 * <td style="text-align:center">0</td>
1247 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1248 * </tbody>
1249 * </table></blockquote>
1250 *
1251 * @param input
1252 * The character sequence to be split
1253 *
1254 * @param limit
1255 * The result threshold, as described above
1256 *
1257 * @return The array of strings computed by splitting the input
1258 * around matches of this pattern
1259 */
1260 public String[] split(CharSequence input, int limit) {
1261 int index = 0;
1262 boolean matchLimited = limit > 0;
1263 ArrayList<String> matchList = new ArrayList<>();
1264 Matcher m = matcher(input);
1265
1266 // Add segments before each match found
1267 while(m.find()) {
1268 if (!matchLimited || matchList.size() < limit - 1) {
1269 if (index == 0 && index == m.start() && m.start() == m.end()) {
1270 // no empty leading substring included for zero-width match
1271 // at the beginning of the input char sequence.
1272 continue;
1273 }
1274 String match = input.subSequence(index, m.start()).toString();
1275 matchList.add(match);
1276 index = m.end();
1277 } else if (matchList.size() == limit - 1) { // last one
1278 String match = input.subSequence(index,
1279 input.length()).toString();
1280 matchList.add(match);
1281 index = m.end();
1282 }
1283 }
1284
1285 // If no match was found, return this
1286 if (index == 0)
1287 return new String[] {input.toString()};
1288
1289 // Add remaining segment
1290 if (!matchLimited || matchList.size() < limit)
1291 matchList.add(input.subSequence(index, input.length()).toString());
1292
1293 // Construct result
1294 int resultSize = matchList.size();
1295 if (limit == 0)
1296 while (resultSize > 0 && matchList.get(resultSize-1).equals(""))
1297 resultSize--;
1298 String[] result = new String[resultSize];
1299 return matchList.subList(0, resultSize).toArray(result);
1300 }
1301
1302 /**
1303 * Splits the given input sequence around matches of this pattern.
1304 *
1305 * <p> This method works as if by invoking the two-argument {@link
1306 * #split(java.lang.CharSequence, int) split} method with the given input
1307 * sequence and a limit argument of zero. Trailing empty strings are
1308 * therefore not included in the resulting array. </p>
1309 *
1310 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1311 * results with these expressions:
1312 *
1313 * <blockquote><table>
1314 * <caption style="display:none">Split examples showing regex and result</caption>
1315 * <thead>
1316 * <tr><th style="text-align:left"><i>Regex </i></th>
1317 * <th style="text-align:left"><i>Result</i></th></tr>
1318 * </thead>
1319 * <tbody>
1320 * <tr><td style="text-align:center">:</td>
1321 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1322 * <tr><td style="text-align:center">o</td>
1323 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1324 * </tbody>
1325 * </table></blockquote>
1326 *
1327 *
1328 * @param input
1329 * The character sequence to be split
1330 *
1331 * @return The array of strings computed by splitting the input
1332 * around matches of this pattern
1333 */
1334 public String[] split(CharSequence input) {
1335 return split(input, 0);
1336 }
1337
1338 /**
1339 * Returns a literal pattern {@code String} for the specified
1340 * {@code String}.
1341 *
1342 * <p>This method produces a {@code String} that can be used to
1343 * create a {@code Pattern} that would match the string
1344 * {@code s} as if it were a literal pattern.</p> Metacharacters
1345 * or escape sequences in the input sequence will be given no special
1346 * meaning.
1347 *
1348 * @param s The string to be literalized
1349 * @return A literal string replacement
1350 * @since 1.5
1351 */
1352 public static String quote(String s) {
1353 int slashEIndex = s.indexOf("\\E");
1354 if (slashEIndex == -1)
1355 return "\\Q" + s + "\\E";
1356
1357 int lenHint = s.length();
1358 lenHint = (lenHint < Integer.MAX_VALUE - 8 - lenHint) ?
1359 (lenHint << 1) : (Integer.MAX_VALUE - 8);
1360
1361 StringBuilder sb = new StringBuilder(lenHint);
1362 sb.append("\\Q");
1363 int current = 0;
1364 do {
1365 sb.append(s, current, slashEIndex)
1366 .append("\\E\\\\E\\Q");
1367 current = slashEIndex + 2;
1368 } while ((slashEIndex = s.indexOf("\\E", current)) != -1);
1369
1370 return sb.append(s, current, s.length())
1371 .append("\\E")
1372 .toString();
1373 }
1374
1375 /**
1376 * Recompile the Pattern instance from a stream. The original pattern
1377 * string is read in and the object tree is recompiled from it.
1378 */
1379 private void readObject(java.io.ObjectInputStream s)
1380 throws java.io.IOException, ClassNotFoundException {
1381
1382 // Read in all fields
1383 s.defaultReadObject();
1384
1385 // Initialize counts
1386 capturingGroupCount = 1;
1387 localCount = 0;
1388 localTCNCount = 0;
1389
1390 // if length > 0, the Pattern is lazily compiled
1391 if (pattern.length() == 0) {
1392 root = new Start(lastAccept);
1393 matchRoot = lastAccept;
1394 compiled = true;
1395 }
1396 }
1397
1398 /**
1399 * This private constructor is used to create all Patterns. The pattern
1400 * string and match flags are all that is needed to completely describe
1401 * a Pattern. An empty pattern string results in an object tree with
1402 * only a Start node and a LastNode node.
1403 */
1404 private Pattern(String p, int f) {
1405 if ((f & ~ALL_FLAGS) != 0) {
1406 throw new IllegalArgumentException("Unknown flag 0x"
1407 + Integer.toHexString(f));
1408 }
1409 pattern = p;
1410 flags = f;
1411
1412 // to use UNICODE_CASE if UNICODE_CHARACTER_CLASS present
1413 if ((flags & UNICODE_CHARACTER_CLASS) != 0)
1414 flags |= UNICODE_CASE;
1415
1416 // Reset group index count
1417 capturingGroupCount = 1;
1418 localCount = 0;
1419 localTCNCount = 0;
1420
1421 if (pattern.length() > 0) {
1422 compile();
1423 } else {
1424 root = new Start(lastAccept);
1425 matchRoot = lastAccept;
1426 }
1427 }
1428
1429 /**
1430 * The pattern is converted to normalized form ({@link
1431 * java.text.Normalizer.Form.NFC NFC}, canonical decomposition,
1432 * followed by canonical composition for the character class
1433 * part, and {@link java.text.Normalizer.Form.NFD NFD},
1434 * canonical decomposition) for the rest), and then a pure
1435 * group is constructed to match canonical equivalences of the
1436 * characters.
1437 */
1438 private static String normalize(String pattern) {
1439 int plen = pattern.length();
1440 StringBuilder pbuf = new StringBuilder(plen);
1441 char last = 0;
1442 int lastStart = 0;
1443 char cc = 0;
1444 for (int i = 0; i < plen;) {
1445 char c = pattern.charAt(i);
1446 if (cc == 0 && // top level
1447 c == '\\' && i + 1 < plen && pattern.charAt(i + 1) == '\\') {
1448 i += 2; last = 0;
1449 continue;
1450 }
1451 if (c == '[' && last != '\\') {
1452 if (cc == 0) {
1453 if (lastStart < i)
1454 normalizeSlice(pattern, lastStart, i, pbuf);
1455 lastStart = i;
1456 }
1457 cc++;
1458 } else if (c == ']' && last != '\\') {
1459 cc--;
1460 if (cc == 0) {
1461 normalizeClazz(pattern, lastStart, i + 1, pbuf);
1462 lastStart = i + 1;
1463 }
1464 }
1465 last = c;
1466 i++;
1467 }
1468 assert (cc == 0);
1469 if (lastStart < plen)
1470 normalizeSlice(pattern, lastStart, plen, pbuf);
1471 return pbuf.toString();
1472 }
1473
1474 private static void normalizeSlice(String src, int off, int limit,
1475 StringBuilder dst)
1476 {
1477 int len = src.length();
1478 int off0 = off;
1479 while (off < limit && ASCII.isAscii(src.charAt(off))) {
1480 off++;
1481 }
1482 if (off == limit) {
1483 dst.append(src, off0, limit);
1484 return;
1485 }
1486 off--;
1487 if (off < off0)
1488 off = off0;
1489 else
1490 dst.append(src, off0, off);
1491 while (off < limit) {
1492 int ch0 = src.codePointAt(off);
1493 if (".$|()[]{}^?*+\\".indexOf(ch0) != -1) {
1494 dst.append((char)ch0);
1495 off++;
1496 continue;
1497 }
1498 int j = off + Character.charCount(ch0);
1499 int ch1;
1500 while (j < limit) {
1501 ch1 = src.codePointAt(j);
1502 if (Grapheme.isBoundary(ch0, ch1))
1503 break;
1504 ch0 = ch1;
1505 j += Character.charCount(ch1);
1506 }
1507 String seq = src.substring(off, j);
1508 String nfd = Normalizer.normalize(seq, Normalizer.Form.NFD);
1509 off = j;
1510 if (nfd.length() > 1) {
1511 ch0 = nfd.codePointAt(0);
1512 ch1 = nfd.codePointAt(Character.charCount(ch0));
1513 if (Character.getType(ch1) == Character.NON_SPACING_MARK) {
1514 Set<String> altns = new LinkedHashSet<>();
1515 altns.add(seq);
1516 produceEquivalentAlternation(nfd, altns);
1517 dst.append("(?:");
1518 altns.forEach( s -> dst.append(s).append('|'));
1519 dst.delete(dst.length() - 1, dst.length());
1520 dst.append(")");
1521 continue;
1522 }
1523 }
1524 String nfc = Normalizer.normalize(seq, Normalizer.Form.NFC);
1525 if (!seq.equals(nfc) && !nfd.equals(nfc))
1526 dst.append("(?:" + seq + "|" + nfd + "|" + nfc + ")");
1527 else if (!seq.equals(nfd))
1528 dst.append("(?:" + seq + "|" + nfd + ")");
1529 else
1530 dst.append(seq);
1531 }
1532 }
1533
1534 private static void normalizeClazz(String src, int off, int limit,
1535 StringBuilder dst)
1536 {
1537 dst.append(Normalizer.normalize(src.substring(off, limit), Form.NFC));
1538 }
1539
1540 /**
1541 * Given a specific sequence composed of a regular character and
1542 * combining marks that follow it, produce the alternation that will
1543 * match all canonical equivalences of that sequence.
1544 */
1545 private static void produceEquivalentAlternation(String src,
1546 Set<String> dst)
1547 {
1548 int len = countChars(src, 0, 1);
1549 if (src.length() == len) {
1550 dst.add(src); // source has one character.
1551 return;
1552 }
1553 String base = src.substring(0,len);
1554 String combiningMarks = src.substring(len);
1555 String[] perms = producePermutations(combiningMarks);
1556 // Add combined permutations
1557 for(int x = 0; x < perms.length; x++) {
1558 String next = base + perms[x];
1559 dst.add(next);
1560 next = composeOneStep(next);
1561 if (next != null) {
1562 produceEquivalentAlternation(next, dst);
1563 }
1564 }
1565 }
1566
1567 /**
1568 * Returns an array of strings that have all the possible
1569 * permutations of the characters in the input string.
1570 * This is used to get a list of all possible orderings
1571 * of a set of combining marks. Note that some of the permutations
1572 * are invalid because of combining class collisions, and these
1573 * possibilities must be removed because they are not canonically
1574 * equivalent.
1575 */
1576 private static String[] producePermutations(String input) {
1577 if (input.length() == countChars(input, 0, 1))
1578 return new String[] {input};
1579
1580 if (input.length() == countChars(input, 0, 2)) {
1581 int c0 = Character.codePointAt(input, 0);
1582 int c1 = Character.codePointAt(input, Character.charCount(c0));
1583 if (getClass(c1) == getClass(c0)) {
1584 return new String[] {input};
1585 }
1586 String[] result = new String[2];
1587 result[0] = input;
1588 StringBuilder sb = new StringBuilder(2);
1589 sb.appendCodePoint(c1);
1590 sb.appendCodePoint(c0);
1591 result[1] = sb.toString();
1592 return result;
1593 }
1594
1595 int length = 1;
1596 int nCodePoints = countCodePoints(input);
1597 for(int x=1; x<nCodePoints; x++)
1598 length = length * (x+1);
1599
1600 String[] temp = new String[length];
1601
1602 int combClass[] = new int[nCodePoints];
1603 for(int x=0, i=0; x<nCodePoints; x++) {
1604 int c = Character.codePointAt(input, i);
1605 combClass[x] = getClass(c);
1606 i += Character.charCount(c);
1607 }
1608
1609 // For each char, take it out and add the permutations
1610 // of the remaining chars
1611 int index = 0;
1612 int len;
1613 // offset maintains the index in code units.
1614 loop: for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
1615 len = countChars(input, offset, 1);
1616 for(int y=x-1; y>=0; y--) {
1617 if (combClass[y] == combClass[x]) {
1618 continue loop;
1619 }
1620 }
1621 StringBuilder sb = new StringBuilder(input);
1622 String otherChars = sb.delete(offset, offset+len).toString();
1623 String[] subResult = producePermutations(otherChars);
1624
1625 String prefix = input.substring(offset, offset+len);
1626 for (String sre : subResult)
1627 temp[index++] = prefix + sre;
1628 }
1629 String[] result = new String[index];
1630 System.arraycopy(temp, 0, result, 0, index);
1631 return result;
1632 }
1633
1634 private static int getClass(int c) {
1635 return sun.text.Normalizer.getCombiningClass(c);
1636 }
1637
1638 /**
1639 * Attempts to compose input by combining the first character
1640 * with the first combining mark following it. Returns a String
1641 * that is the composition of the leading character with its first
1642 * combining mark followed by the remaining combining marks. Returns
1643 * null if the first two characters cannot be further composed.
1644 */
1645 private static String composeOneStep(String input) {
1646 int len = countChars(input, 0, 2);
1647 String firstTwoCharacters = input.substring(0, len);
1648 String result = Normalizer.normalize(firstTwoCharacters, Normalizer.Form.NFC);
1649 if (result.equals(firstTwoCharacters))
1650 return null;
1651 else {
1652 String remainder = input.substring(len);
1653 return result + remainder;
1654 }
1655 }
1656
1657 /**
1658 * Preprocess any \Q...\E sequences in `temp', meta-quoting them.
1659 * See the description of `quotemeta' in perlfunc(1).
1660 */
1661 private void RemoveQEQuoting() {
1662 final int pLen = patternLength;
1663 int i = 0;
1664 while (i < pLen-1) {
1665 if (temp[i] != '\\')
1666 i += 1;
1667 else if (temp[i + 1] != 'Q')
1668 i += 2;
1669 else
1670 break;
1671 }
1672 if (i >= pLen - 1) // No \Q sequence found
1673 return;
1674 int j = i;
1675 i += 2;
1676 int[] newtemp = new int[j + 3*(pLen-i) + 2];
1677 System.arraycopy(temp, 0, newtemp, 0, j);
1678
1679 boolean inQuote = true;
1680 boolean beginQuote = true;
1681 while (i < pLen) {
1682 int c = temp[i++];
1683 if (!ASCII.isAscii(c) || ASCII.isAlpha(c)) {
1684 newtemp[j++] = c;
1685 } else if (ASCII.isDigit(c)) {
1686 if (beginQuote) {
1687 /*
1688 * A unicode escape \[0xu] could be before this quote,
1689 * and we don't want this numeric char to processed as
1690 * part of the escape.
1691 */
1692 newtemp[j++] = '\\';
1693 newtemp[j++] = 'x';
1694 newtemp[j++] = '3';
1695 }
1696 newtemp[j++] = c;
1697 } else if (c != '\\') {
1698 if (inQuote) newtemp[j++] = '\\';
1699 newtemp[j++] = c;
1700 } else if (inQuote) {
1701 if (temp[i] == 'E') {
1702 i++;
1703 inQuote = false;
1704 } else {
1705 newtemp[j++] = '\\';
1706 newtemp[j++] = '\\';
1707 }
1708 } else {
1709 if (temp[i] == 'Q') {
1710 i++;
1711 inQuote = true;
1712 beginQuote = true;
1713 continue;
1714 } else {
1715 newtemp[j++] = c;
1716 if (i != pLen)
1717 newtemp[j++] = temp[i++];
1718 }
1719 }
1720
1721 beginQuote = false;
1722 }
1723
1724 patternLength = j;
1725 temp = Arrays.copyOf(newtemp, j + 2); // double zero termination
1726 }
1727
1728 /**
1729 * Copies regular expression to an int array and invokes the parsing
1730 * of the expression which will create the object tree.
1731 */
1732 private void compile() {
1733 // Handle canonical equivalences
1734 if (has(CANON_EQ) && !has(LITERAL)) {
1735 normalizedPattern = normalize(pattern);
1736 } else {
1737 normalizedPattern = pattern;
1738 }
1739 patternLength = normalizedPattern.length();
1740
1741 // Copy pattern to int array for convenience
1742 // Use double zero to terminate pattern
1743 temp = new int[patternLength + 2];
1744
1745 hasSupplementary = false;
1746 int c, count = 0;
1747 // Convert all chars into code points
1748 for (int x = 0; x < patternLength; x += Character.charCount(c)) {
1749 c = normalizedPattern.codePointAt(x);
1750 if (isSupplementary(c)) {
1751 hasSupplementary = true;
1752 }
1753 temp[count++] = c;
1754 }
1755
1756 patternLength = count; // patternLength now in code points
1757
1758 if (! has(LITERAL))
1759 RemoveQEQuoting();
1760
1761 // Allocate all temporary objects here.
1762 buffer = new int[32];
1763 groupNodes = new GroupHead[10];
1764 namedGroups = null;
1765 topClosureNodes = new ArrayList<>(10);
1766
1767 if (has(LITERAL)) {
1768 // Literal pattern handling
1769 matchRoot = newSlice(temp, patternLength, hasSupplementary);
1770 matchRoot.next = lastAccept;
1771 } else {
1772 // Start recursive descent parsing
1773 matchRoot = expr(lastAccept);
1774 // Check extra pattern characters
1775 if (patternLength != cursor) {
1776 if (peek() == ')') {
1777 throw error("Unmatched closing ')'");
1778 } else {
1779 throw error("Unexpected internal error");
1780 }
1781 }
1782 }
1783
1784 // Peephole optimization
1785 if (matchRoot instanceof Slice) {
1786 root = BnM.optimize(matchRoot);
1787 if (root == matchRoot) {
1788 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1789 }
1790 } else if (matchRoot instanceof Begin || matchRoot instanceof First) {
1791 root = matchRoot;
1792 } else {
1793 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1794 }
1795
1796 // Optimize the greedy Loop to prevent exponential backtracking, IF there
1797 // is no group ref in this pattern. With a non-negative localTCNCount value,
1798 // the greedy type Loop, Curly will skip the backtracking for any starting
1799 // position "i" that failed in the past.
1800 if (!hasGroupRef) {
1801 for (Node node : topClosureNodes) {
1802 if (node instanceof Loop) {
1803 // non-deterministic-greedy-group
1804 ((Loop)node).posIndex = localTCNCount++;
1805 }
1806 }
1807 }
1808
1809 // Release temporary storage
1810 temp = null;
1811 buffer = null;
1812 groupNodes = null;
1813 patternLength = 0;
1814 compiled = true;
1815 topClosureNodes = null;
1816 }
1817
1818 Map<String, Integer> namedGroups() {
1819 Map<String, Integer> groups = namedGroups;
1820 if (groups == null) {
1821 namedGroups = groups = new HashMap<>(2);
1822 }
1823 return groups;
1824 }
1825
1826 /**
1827 * Used to accumulate information about a subtree of the object graph
1828 * so that optimizations can be applied to the subtree.
1829 */
1830 static final class TreeInfo {
1831 int minLength;
1832 int maxLength;
1833 boolean maxValid;
1834 boolean deterministic;
1835
1836 TreeInfo() {
1837 reset();
1838 }
1839 void reset() {
1840 minLength = 0;
1841 maxLength = 0;
1842 maxValid = true;
1843 deterministic = true;
1844 }
1845 }
1846
1847 /*
1848 * The following private methods are mainly used to improve the
1849 * readability of the code. In order to let the Java compiler easily
1850 * inline them, we should not put many assertions or error checks in them.
1851 */
1852
1853 /**
1854 * Indicates whether a particular flag is set or not.
1855 */
1856 private boolean has(int f) {
1857 return (flags & f) != 0;
1858 }
1859
1860 /**
1861 * Match next character, signal error if failed.
1862 */
1863 private void accept(int ch, String s) {
1864 int testChar = temp[cursor++];
1865 if (has(COMMENTS))
1866 testChar = parsePastWhitespace(testChar);
1867 if (ch != testChar) {
1868 throw error(s);
1869 }
1870 }
1871
1872 /**
1873 * Mark the end of pattern with a specific character.
1874 */
1875 private void mark(int c) {
1876 temp[patternLength] = c;
1877 }
1878
1879 /**
1880 * Peek the next character, and do not advance the cursor.
1881 */
1882 private int peek() {
1883 int ch = temp[cursor];
1884 if (has(COMMENTS))
1885 ch = peekPastWhitespace(ch);
1886 return ch;
1887 }
1888
1889 /**
1890 * Read the next character, and advance the cursor by one.
1891 */
1892 private int read() {
1893 int ch = temp[cursor++];
1894 if (has(COMMENTS))
1895 ch = parsePastWhitespace(ch);
1896 return ch;
1897 }
1898
1899 /**
1900 * Read the next character, and advance the cursor by one,
1901 * ignoring the COMMENTS setting
1902 */
1903 private int readEscaped() {
1904 int ch = temp[cursor++];
1905 return ch;
1906 }
1907
1908 /**
1909 * Advance the cursor by one, and peek the next character.
1910 */
1911 private int next() {
1912 int ch = temp[++cursor];
1913 if (has(COMMENTS))
1914 ch = peekPastWhitespace(ch);
1915 return ch;
1916 }
1917
1918 /**
1919 * Advance the cursor by one, and peek the next character,
1920 * ignoring the COMMENTS setting
1921 */
1922 private int nextEscaped() {
1923 int ch = temp[++cursor];
1924 return ch;
1925 }
1926
1927 /**
1928 * If in xmode peek past whitespace and comments.
1929 */
1930 private int peekPastWhitespace(int ch) {
1931 while (ASCII.isSpace(ch) || ch == '#') {
1932 while (ASCII.isSpace(ch))
1933 ch = temp[++cursor];
1934 if (ch == '#') {
1935 ch = peekPastLine();
1936 }
1937 }
1938 return ch;
1939 }
1940
1941 /**
1942 * If in xmode parse past whitespace and comments.
1943 */
1944 private int parsePastWhitespace(int ch) {
1945 while (ASCII.isSpace(ch) || ch == '#') {
1946 while (ASCII.isSpace(ch))
1947 ch = temp[cursor++];
1948 if (ch == '#')
1949 ch = parsePastLine();
1950 }
1951 return ch;
1952 }
1953
1954 /**
1955 * xmode parse past comment to end of line.
1956 */
1957 private int parsePastLine() {
1958 int ch = temp[cursor++];
1959 while (ch != 0 && !isLineSeparator(ch))
1960 ch = temp[cursor++];
1961 return ch;
1962 }
1963
1964 /**
1965 * xmode peek past comment to end of line.
1966 */
1967 private int peekPastLine() {
1968 int ch = temp[++cursor];
1969 while (ch != 0 && !isLineSeparator(ch))
1970 ch = temp[++cursor];
1971 return ch;
1972 }
1973
1974 /**
1975 * Determines if character is a line separator in the current mode
1976 */
1977 private boolean isLineSeparator(int ch) {
1978 if (has(UNIX_LINES)) {
1979 return ch == '\n';
1980 } else {
1981 return (ch == '\n' ||
1982 ch == '\r' ||
1983 (ch|1) == '\u2029' ||
1984 ch == '\u0085');
1985 }
1986 }
1987
1988 /**
1989 * Read the character after the next one, and advance the cursor by two.
1990 */
1991 private int skip() {
1992 int i = cursor;
1993 int ch = temp[i+1];
1994 cursor = i + 2;
1995 return ch;
1996 }
1997
1998 /**
1999 * Unread one next character, and retreat cursor by one.
2000 */
2001 private void unread() {
2002 cursor--;
2003 }
2004
2005 /**
2006 * Internal method used for handling all syntax errors. The pattern is
2007 * displayed with a pointer to aid in locating the syntax error.
2008 */
2009 private PatternSyntaxException error(String s) {
2010 return new PatternSyntaxException(s, normalizedPattern, cursor - 1);
2011 }
2012
2013 /**
2014 * Determines if there is any supplementary character or unpaired
2015 * surrogate in the specified range.
2016 */
2017 private boolean findSupplementary(int start, int end) {
2018 for (int i = start; i < end; i++) {
2019 if (isSupplementary(temp[i]))
2020 return true;
2021 }
2022 return false;
2023 }
2024
2025 /**
2026 * Determines if the specified code point is a supplementary
2027 * character or unpaired surrogate.
2028 */
2029 private static final boolean isSupplementary(int ch) {
2030 return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT ||
2031 Character.isSurrogate((char)ch);
2032 }
2033
2034 /**
2035 * The following methods handle the main parsing. They are sorted
2036 * according to their precedence order, the lowest one first.
2037 */
2038
2039 /**
2040 * The expression is parsed with branch nodes added for alternations.
2041 * This may be called recursively to parse sub expressions that may
2042 * contain alternations.
2043 */
2044 private Node expr(Node end) {
2045 Node prev = null;
2046 Node firstTail = null;
2047 Branch branch = null;
2048 Node branchConn = null;
2049
2050 for (;;) {
2051 Node node = sequence(end);
2052 Node nodeTail = root; //double return
2053 if (prev == null) {
2054 prev = node;
2055 firstTail = nodeTail;
2056 } else {
2057 // Branch
2058 if (branchConn == null) {
2059 branchConn = new BranchConn();
2060 branchConn.next = end;
2061 }
2062 if (node == end) {
2063 // if the node returned from sequence() is "end"
2064 // we have an empty expr, set a null atom into
2065 // the branch to indicate to go "next" directly.
2066 node = null;
2067 } else {
2068 // the "tail.next" of each atom goes to branchConn
2069 nodeTail.next = branchConn;
2070 }
2071 if (prev == branch) {
2072 branch.add(node);
2073 } else {
2074 if (prev == end) {
2075 prev = null;
2076 } else {
2077 // replace the "end" with "branchConn" at its tail.next
2078 // when put the "prev" into the branch as the first atom.
2079 firstTail.next = branchConn;
2080 }
2081 prev = branch = new Branch(prev, node, branchConn);
2082 }
2083 }
2084 if (peek() != '|') {
2085 return prev;
2086 }
2087 next();
2088 }
2089 }
2090
2091 @SuppressWarnings("fallthrough")
2092 /**
2093 * Parsing of sequences between alternations.
2094 */
2095 private Node sequence(Node end) {
2096 Node head = null;
2097 Node tail = null;
2098 Node node = null;
2099 LOOP:
2100 for (;;) {
2101 int ch = peek();
2102 switch (ch) {
2103 case '(':
2104 // Because group handles its own closure,
2105 // we need to treat it differently
2106 node = group0();
2107 // Check for comment or flag group
2108 if (node == null)
2109 continue;
2110 if (head == null)
2111 head = node;
2112 else
2113 tail.next = node;
2114 // Double return: Tail was returned in root
2115 tail = root;
2116 continue;
2117 case '[':
2118 if (has(CANON_EQ) && !has(LITERAL))
2119 node = new NFCCharProperty(clazz(true));
2120 else
2121 node = newCharProperty(clazz(true));
2122 break;
2123 case '\\':
2124 ch = nextEscaped();
2125 if (ch == 'p' || ch == 'P') {
2126 boolean oneLetter = true;
2127 boolean comp = (ch == 'P');
2128 ch = next(); // Consume { if present
2129 if (ch != '{') {
2130 unread();
2131 } else {
2132 oneLetter = false;
2133 }
2134 // node = newCharProperty(family(oneLetter, comp));
2135 if (has(CANON_EQ) && !has(LITERAL))
2136 node = new NFCCharProperty(family(oneLetter, comp));
2137 else
2138 node = newCharProperty(family(oneLetter, comp));
2139 } else {
2140 unread();
2141 node = atom();
2142 }
2143 break;
2144 case '^':
2145 next();
2146 if (has(MULTILINE)) {
2147 if (has(UNIX_LINES))
2148 node = new UnixCaret();
2149 else
2150 node = new Caret();
2151 } else {
2152 node = new Begin();
2153 }
2154 break;
2155 case '$':
2156 next();
2157 if (has(UNIX_LINES))
2158 node = new UnixDollar(has(MULTILINE));
2159 else
2160 node = new Dollar(has(MULTILINE));
2161 break;
2162 case '.':
2163 next();
2164 if (has(DOTALL)) {
2165 node = new CharProperty(ALL());
2166 } else {
2167 if (has(UNIX_LINES)) {
2168 node = new CharProperty(UNIXDOT());
2169 } else {
2170 node = new CharProperty(DOT());
2171 }
2172 }
2173 break;
2174 case '|':
2175 case ')':
2176 break LOOP;
2177 case ']': // Now interpreting dangling ] and } as literals
2178 case '}':
2179 node = atom();
2180 break;
2181 case '?':
2182 case '*':
2183 case '+':
2184 next();
2185 throw error("Dangling meta character '" + ((char)ch) + "'");
2186 case 0:
2187 if (cursor >= patternLength) {
2188 break LOOP;
2189 }
2190 // Fall through
2191 default:
2192 node = atom();
2193 break;
2194 }
2195
2196 node = closure(node);
2197 /* save the top dot-greedy nodes (.*, .+) as well
2198 if (node instanceof GreedyCharProperty &&
2199 ((GreedyCharProperty)node).cp instanceof Dot) {
2200 topClosureNodes.add(node);
2201 }
2202 */
2203 if (head == null) {
2204 head = tail = node;
2205 } else {
2206 tail.next = node;
2207 tail = node;
2208 }
2209 }
2210 if (head == null) {
2211 return end;
2212 }
2213 tail.next = end;
2214 root = tail; //double return
2215 return head;
2216 }
2217
2218 @SuppressWarnings("fallthrough")
2219 /**
2220 * Parse and add a new Single or Slice.
2221 */
2222 private Node atom() {
2223 int first = 0;
2224 int prev = -1;
2225 boolean hasSupplementary = false;
2226 int ch = peek();
2227 for (;;) {
2228 switch (ch) {
2229 case '*':
2230 case '+':
2231 case '?':
2232 case '{':
2233 if (first > 1) {
2234 cursor = prev; // Unwind one character
2235 first--;
2236 }
2237 break;
2238 case '$':
2239 case '.':
2240 case '^':
2241 case '(':
2242 case '[':
2243 case '|':
2244 case ')':
2245 break;
2246 case '\\':
2247 ch = nextEscaped();
2248 if (ch == 'p' || ch == 'P') { // Property
2249 if (first > 0) { // Slice is waiting; handle it first
2250 unread();
2251 break;
2252 } else { // No slice; just return the family node
2253 boolean comp = (ch == 'P');
2254 boolean oneLetter = true;
2255 ch = next(); // Consume { if present
2256 if (ch != '{')
2257 unread();
2258 else
2259 oneLetter = false;
2260 if (has(CANON_EQ) && !has(LITERAL))
2261 return new NFCCharProperty(family(oneLetter, comp));
2262 else
2263 return newCharProperty(family(oneLetter, comp));
2264 }
2265 }
2266 unread();
2267 prev = cursor;
2268 ch = escape(false, first == 0, false);
2269 if (ch >= 0) {
2270 append(ch, first);
2271 first++;
2272 if (isSupplementary(ch)) {
2273 hasSupplementary = true;
2274 }
2275 ch = peek();
2276 continue;
2277 } else if (first == 0) {
2278 return root;
2279 }
2280 // Unwind meta escape sequence
2281 cursor = prev;
2282 break;
2283 case 0:
2284 if (cursor >= patternLength) {
2285 break;
2286 }
2287 // Fall through
2288 default:
2289 prev = cursor;
2290 append(ch, first);
2291 first++;
2292 if (isSupplementary(ch)) {
2293 hasSupplementary = true;
2294 }
2295 ch = next();
2296 continue;
2297 }
2298 break;
2299 }
2300 if (first == 1) {
2301 return newCharProperty(single(buffer[0]));
2302 } else {
2303 return newSlice(buffer, first, hasSupplementary);
2304 }
2305 }
2306
2307 private void append(int ch, int len) {
2308 if (len >= buffer.length) {
2309 int[] tmp = new int[len+len];
2310 System.arraycopy(buffer, 0, tmp, 0, len);
2311 buffer = tmp;
2312 }
2313 buffer[len] = ch;
2314 }
2315
2316 /**
2317 * Parses a backref greedily, taking as many numbers as it
2318 * can. The first digit is always treated as a backref, but
2319 * multi digit numbers are only treated as a backref if at
2320 * least that many backrefs exist at this point in the regex.
2321 */
2322 private Node ref(int refNum) {
2323 boolean done = false;
2324 while(!done) {
2325 int ch = peek();
2326 switch(ch) {
2327 case '0':
2328 case '1':
2329 case '2':
2330 case '3':
2331 case '4':
2332 case '5':
2333 case '6':
2334 case '7':
2335 case '8':
2336 case '9':
2337 int newRefNum = (refNum * 10) + (ch - '0');
2338 // Add another number if it doesn't make a group
2339 // that doesn't exist
2340 if (capturingGroupCount - 1 < newRefNum) {
2341 done = true;
2342 break;
2343 }
2344 refNum = newRefNum;
2345 read();
2346 break;
2347 default:
2348 done = true;
2349 break;
2350 }
2351 }
2352 hasGroupRef = true;
2353 if (has(CASE_INSENSITIVE))
2354 return new CIBackRef(refNum, has(UNICODE_CASE));
2355 else
2356 return new BackRef(refNum);
2357 }
2358
2359 /**
2360 * Parses an escape sequence to determine the actual value that needs
2361 * to be matched.
2362 * If -1 is returned and create was true a new object was added to the tree
2363 * to handle the escape sequence.
2364 * If the returned value is greater than zero, it is the value that
2365 * matches the escape sequence.
2366 */
2367 private int escape(boolean inclass, boolean create, boolean isrange) {
2368 int ch = skip();
2369 switch (ch) {
2370 case '0':
2371 return o();
2372 case '1':
2373 case '2':
2374 case '3':
2375 case '4':
2376 case '5':
2377 case '6':
2378 case '7':
2379 case '8':
2380 case '9':
2381 if (inclass) break;
2382 if (create) {
2383 root = ref((ch - '0'));
2384 }
2385 return -1;
2386 case 'A':
2387 if (inclass) break;
2388 if (create) root = new Begin();
2389 return -1;
2390 case 'B':
2391 if (inclass) break;
2392 if (create) root = new Bound(Bound.NONE, has(UNICODE_CHARACTER_CLASS));
2393 return -1;
2394 case 'C':
2395 break;
2396 case 'D':
2397 if (create) {
2398 predicate = has(UNICODE_CHARACTER_CLASS) ?
2399 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2400 predicate = predicate.negate();
2401 if (!inclass)
2402 root = newCharProperty(predicate);
2403 }
2404 return -1;
2405 case 'E':
2406 case 'F':
2407 break;
2408 case 'G':
2409 if (inclass) break;
2410 if (create) root = new LastMatch();
2411 return -1;
2412 case 'H':
2413 if (create) {
2414 predicate = HorizWS().negate();
2415 if (!inclass)
2416 root = newCharProperty(predicate);
2417 }
2418 return -1;
2419 case 'I':
2420 case 'J':
2421 case 'K':
2422 case 'L':
2423 case 'M':
2424 break;
2425 case 'N':
2426 return N();
2427 case 'O':
2428 case 'P':
2429 case 'Q':
2430 break;
2431 case 'R':
2432 if (inclass) break;
2433 if (create) root = new LineEnding();
2434 return -1;
2435 case 'S':
2436 if (create) {
2437 predicate = has(UNICODE_CHARACTER_CLASS) ?
2438 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2439 predicate = predicate.negate();
2440 if (!inclass)
2441 root = newCharProperty(predicate);
2442 }
2443 return -1;
2444 case 'T':
2445 case 'U':
2446 break;
2447 case 'V':
2448 if (create) {
2449 predicate = VertWS().negate();
2450 if (!inclass)
2451 root = newCharProperty(predicate);
2452 }
2453 return -1;
2454 case 'W':
2455 if (create) {
2456 predicate = has(UNICODE_CHARACTER_CLASS) ?
2457 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2458 predicate = predicate.negate();
2459 if (!inclass)
2460 root = newCharProperty(predicate);
2461 }
2462 return -1;
2463 case 'X':
2464 if (inclass) break;
2465 if (create) {
2466 root = new XGrapheme();
2467 }
2468 return -1;
2469 case 'Y':
2470 break;
2471 case 'Z':
2472 if (inclass) break;
2473 if (create) {
2474 if (has(UNIX_LINES))
2475 root = new UnixDollar(false);
2476 else
2477 root = new Dollar(false);
2478 }
2479 return -1;
2480 case 'a':
2481 return '\007';
2482 case 'b':
2483 if (inclass) break;
2484 if (create) {
2485 if (peek() == '{') {
2486 if (skip() == 'g') {
2487 if (read() == '}') {
2488 root = new GraphemeBound();
2489 return -1;
2490 }
2491 break; // error missing trailing }
2492 }
2493 unread(); unread();
2494 }
2495 root = new Bound(Bound.BOTH, has(UNICODE_CHARACTER_CLASS));
2496 }
2497 return -1;
2498 case 'c':
2499 return c();
2500 case 'd':
2501 if (create) {
2502 predicate = has(UNICODE_CHARACTER_CLASS) ?
2503 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2504 if (!inclass)
2505 root = newCharProperty(predicate);
2506 }
2507 return -1;
2508 case 'e':
2509 return '\033';
2510 case 'f':
2511 return '\f';
2512 case 'g':
2513 break;
2514 case 'h':
2515 if (create) {
2516 predicate = HorizWS();
2517 if (!inclass)
2518 root = newCharProperty(predicate);
2519 }
2520 return -1;
2521 case 'i':
2522 case 'j':
2523 break;
2524 case 'k':
2525 if (inclass)
2526 break;
2527 if (read() != '<')
2528 throw error("\\k is not followed by '<' for named capturing group");
2529 String name = groupname(read());
2530 if (!namedGroups().containsKey(name))
2531 throw error("(named capturing group <"+ name+"> does not exit");
2532 if (create) {
2533 hasGroupRef = true;
2534 if (has(CASE_INSENSITIVE))
2535 root = new CIBackRef(namedGroups().get(name), has(UNICODE_CASE));
2536 else
2537 root = new BackRef(namedGroups().get(name));
2538 }
2539 return -1;
2540 case 'l':
2541 case 'm':
2542 break;
2543 case 'n':
2544 return '\n';
2545 case 'o':
2546 case 'p':
2547 case 'q':
2548 break;
2549 case 'r':
2550 return '\r';
2551 case 's':
2552 if (create) {
2553 predicate = has(UNICODE_CHARACTER_CLASS) ?
2554 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2555 if (!inclass)
2556 root = newCharProperty(predicate);
2557 }
2558 return -1;
2559 case 't':
2560 return '\t';
2561 case 'u':
2562 return u();
2563 case 'v':
2564 // '\v' was implemented as VT/0x0B in releases < 1.8 (though
2565 // undocumented). In JDK8 '\v' is specified as a predefined
2566 // character class for all vertical whitespace characters.
2567 // So [-1, root=VertWS node] pair is returned (instead of a
2568 // single 0x0B). This breaks the range if '\v' is used as
2569 // the start or end value, such as [\v-...] or [...-\v], in
2570 // which a single definite value (0x0B) is expected. For
2571 // compatibility concern '\013'/0x0B is returned if isrange.
2572 if (isrange)
2573 return '\013';
2574 if (create) {
2575 predicate = VertWS();
2576 if (!inclass)
2577 root = newCharProperty(predicate);
2578 }
2579 return -1;
2580 case 'w':
2581 if (create) {
2582 predicate = has(UNICODE_CHARACTER_CLASS) ?
2583 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2584 if (!inclass)
2585 root = newCharProperty(predicate);
2586 }
2587 return -1;
2588 case 'x':
2589 return x();
2590 case 'y':
2591 break;
2592 case 'z':
2593 if (inclass) break;
2594 if (create) root = new End();
2595 return -1;
2596 default:
2597 return ch;
2598 }
2599 throw error("Illegal/unsupported escape sequence");
2600 }
2601
2602 /**
2603 * Parse a character class, and return the node that matches it.
2604 *
2605 * Consumes a ] on the way out if consume is true. Usually consume
2606 * is true except for the case of [abc&&def] where def is a separate
2607 * right hand node with "understood" brackets.
2608 */
2609 private CharPredicate clazz(boolean consume) {
2610 CharPredicate prev = null;
2611 CharPredicate curr = null;
2612 BitClass bits = new BitClass();
2613 BmpCharPredicate bitsP = ch -> ch < 256 && bits.bits[ch];
2614
2615 boolean isNeg = false;
2616 boolean hasBits = false;
2617 int ch = next();
2618
2619 // Negates if first char in a class, otherwise literal
2620 if (ch == '^' && temp[cursor-1] == '[') {
2621 ch = next();
2622 isNeg = true;
2623 }
2624 for (;;) {
2625 switch (ch) {
2626 case '[':
2627 curr = clazz(true);
2628 if (prev == null)
2629 prev = curr;
2630 else
2631 prev = prev.union(curr);
2632 ch = peek();
2633 continue;
2634 case '&':
2635 ch = next();
2636 if (ch == '&') {
2637 ch = next();
2638 CharPredicate right = null;
2639 while (ch != ']' && ch != '&') {
2640 if (ch == '[') {
2641 if (right == null)
2642 right = clazz(true);
2643 else
2644 right = right.union(clazz(true));
2645 } else { // abc&&def
2646 unread();
2647 right = clazz(false);
2648 }
2649 ch = peek();
2650 }
2651 if (hasBits) {
2652 // bits used, union has high precedence
2653 if (prev == null) {
2654 prev = curr = bitsP;
2655 } else {
2656 prev = prev.union(bitsP);
2657 }
2658 hasBits = false;
2659 }
2660 if (right != null)
2661 curr = right;
2662 if (prev == null) {
2663 if (right == null)
2664 throw error("Bad class syntax");
2665 else
2666 prev = right;
2667 } else {
2668 prev = prev.and(curr);
2669 }
2670 } else {
2671 // treat as a literal &
2672 unread();
2673 break;
2674 }
2675 continue;
2676 case 0:
2677 if (cursor >= patternLength)
2678 throw error("Unclosed character class");
2679 break;
2680 case ']':
2681 if (prev != null || hasBits) {
2682 if (consume)
2683 next();
2684 if (prev == null)
2685 prev = bitsP;
2686 else if (hasBits)
2687 prev = prev.union(bitsP);
2688 if (isNeg)
2689 return prev.negate();
2690 return prev;
2691 }
2692 break;
2693 default:
2694 break;
2695 }
2696 curr = range(bits);
2697 if (curr == null) { // the bits used
2698 hasBits = true;
2699 } else {
2700 if (prev == null)
2701 prev = curr;
2702 else if (prev != curr)
2703 prev = prev.union(curr);
2704 }
2705 ch = peek();
2706 }
2707 }
2708
2709 private CharPredicate bitsOrSingle(BitClass bits, int ch) {
2710 /* Bits can only handle codepoints in [u+0000-u+00ff] range.
2711 Use "single" node instead of bits when dealing with unicode
2712 case folding for codepoints listed below.
2713 (1)Uppercase out of range: u+00ff, u+00b5
2714 toUpperCase(u+00ff) -> u+0178
2715 toUpperCase(u+00b5) -> u+039c
2716 (2)LatinSmallLetterLongS u+17f
2717 toUpperCase(u+017f) -> u+0053
2718 (3)LatinSmallLetterDotlessI u+131
2719 toUpperCase(u+0131) -> u+0049
2720 (4)LatinCapitalLetterIWithDotAbove u+0130
2721 toLowerCase(u+0130) -> u+0069
2722 (5)KelvinSign u+212a
2723 toLowerCase(u+212a) ==> u+006B
2724 (6)AngstromSign u+212b
2725 toLowerCase(u+212b) ==> u+00e5
2726 */
2727 if (ch < 256 &&
2728 !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) &&
2729 (ch == 0xff || ch == 0xb5 ||
2730 ch == 0x49 || ch == 0x69 || //I and i
2731 ch == 0x53 || ch == 0x73 || //S and s
2732 ch == 0x4b || ch == 0x6b || //K and k
2733 ch == 0xc5 || ch == 0xe5))) { //A+ring
2734 bits.add(ch, flags());
2735 return null;
2736 }
2737 return single(ch);
2738 }
2739
2740 /**
2741 * Returns a suitably optimized, single character predicate
2742 */
2743 private CharPredicate single(final int ch) {
2744 if (has(CASE_INSENSITIVE)) {
2745 int lower, upper;
2746 if (has(UNICODE_CASE)) {
2747 upper = Character.toUpperCase(ch);
2748 lower = Character.toLowerCase(upper);
2749 // Unicode case insensitive matches
2750 if (upper != lower)
2751 return SingleU(lower);
2752 } else if (ASCII.isAscii(ch)) {
2753 lower = ASCII.toLower(ch);
2754 upper = ASCII.toUpper(ch);
2755 // Case insensitive matches a given BMP character
2756 if (lower != upper)
2757 return SingleI(lower, upper);
2758 }
2759 }
2760 if (isSupplementary(ch))
2761 return SingleS(ch);
2762 return Single(ch); // Match a given BMP character
2763 }
2764
2765 /**
2766 * Parse a single character or a character range in a character class
2767 * and return its representative node.
2768 */
2769 private CharPredicate range(BitClass bits) {
2770 int ch = peek();
2771 if (ch == '\\') {
2772 ch = nextEscaped();
2773 if (ch == 'p' || ch == 'P') { // A property
2774 boolean comp = (ch == 'P');
2775 boolean oneLetter = true;
2776 // Consume { if present
2777 ch = next();
2778 if (ch != '{')
2779 unread();
2780 else
2781 oneLetter = false;
2782 return family(oneLetter, comp);
2783 } else { // ordinary escape
2784 boolean isrange = temp[cursor+1] == '-';
2785 unread();
2786 ch = escape(true, true, isrange);
2787 if (ch == -1)
2788 return predicate;
2789 }
2790 } else {
2791 next();
2792 }
2793 if (ch >= 0) {
2794 if (peek() == '-') {
2795 int endRange = temp[cursor+1];
2796 if (endRange == '[') {
2797 return bitsOrSingle(bits, ch);
2798 }
2799 if (endRange != ']') {
2800 next();
2801 int m = peek();
2802 if (m == '\\') {
2803 m = escape(true, false, true);
2804 } else {
2805 next();
2806 }
2807 if (m < ch) {
2808 throw error("Illegal character range");
2809 }
2810 if (has(CASE_INSENSITIVE)) {
2811 if (has(UNICODE_CASE))
2812 return CIRangeU(ch, m);
2813 return CIRange(ch, m);
2814 } else {
2815 return Range(ch, m);
2816 }
2817 }
2818 }
2819 return bitsOrSingle(bits, ch);
2820 }
2821 throw error("Unexpected character '"+((char)ch)+"'");
2822 }
2823
2824 /**
2825 * Parses a Unicode character family and returns its representative node.
2826 */
2827 private CharPredicate family(boolean singleLetter, boolean isComplement) {
2828 next();
2829 String name;
2830 CharPredicate p = null;
2831
2832 if (singleLetter) {
2833 int c = temp[cursor];
2834 if (!Character.isSupplementaryCodePoint(c)) {
2835 name = String.valueOf((char)c);
2836 } else {
2837 name = new String(temp, cursor, 1);
2838 }
2839 read();
2840 } else {
2841 int i = cursor;
2842 mark('}');
2843 while(read() != '}') {
2844 }
2845 mark('\000');
2846 int j = cursor;
2847 if (j > patternLength)
2848 throw error("Unclosed character family");
2849 if (i + 1 >= j)
2850 throw error("Empty character family");
2851 name = new String(temp, i, j-i-1);
2852 }
2853
2854 int i = name.indexOf('=');
2855 if (i != -1) {
2856 // property construct \p{name=value}
2857 String value = name.substring(i + 1);
2858 name = name.substring(0, i).toLowerCase(Locale.ENGLISH);
2859 switch (name) {
2860 case "sc":
2861 case "script":
2862 p = CharPredicates.forUnicodeScript(value);
2863 break;
2864 case "blk":
2865 case "block":
2866 p = CharPredicates.forUnicodeBlock(value);
2867 break;
2868 case "gc":
2869 case "general_category":
2870 p = CharPredicates.forProperty(value);
2871 break;
2872 default:
2873 break;
2874 }
2875 if (p == null)
2876 throw error("Unknown Unicode property {name=<" + name + ">, "
2877 + "value=<" + value + ">}");
2878
2879 } else {
2880 if (name.startsWith("In")) {
2881 // \p{InBlockName}
2882 p = CharPredicates.forUnicodeBlock(name.substring(2));
2883 } else if (name.startsWith("Is")) {
2884 // \p{IsGeneralCategory} and \p{IsScriptName}
2885 name = name.substring(2);
2886 p = CharPredicates.forUnicodeProperty(name);
2887 if (p == null)
2888 p = CharPredicates.forProperty(name);
2889 if (p == null)
2890 p = CharPredicates.forUnicodeScript(name);
2891 } else {
2892 if (has(UNICODE_CHARACTER_CLASS)) {
2893 p = CharPredicates.forPOSIXName(name);
2894 }
2895 if (p == null)
2896 p = CharPredicates.forProperty(name);
2897 }
2898 if (p == null)
2899 throw error("Unknown character property name {In/Is" + name + "}");
2900 }
2901 if (isComplement) {
2902 // it might be too expensive to detect if a complement of
2903 // CharProperty can match "certain" supplementary. So just
2904 // go with StartS.
2905 hasSupplementary = true;
2906 p = p.negate();
2907 }
2908 return p;
2909 }
2910
2911 private CharProperty newCharProperty(CharPredicate p) {
2912 if (p == null)
2913 return null;
2914 if (p instanceof BmpCharPredicate)
2915 return new BmpCharProperty((BmpCharPredicate)p);
2916 else
2917 return new CharProperty(p);
2918 }
2919
2920 /**
2921 * Parses and returns the name of a "named capturing group", the trailing
2922 * ">" is consumed after parsing.
2923 */
2924 private String groupname(int ch) {
2925 StringBuilder sb = new StringBuilder();
2926 sb.append(Character.toChars(ch));
2927 while (ASCII.isLower(ch=read()) || ASCII.isUpper(ch) ||
2928 ASCII.isDigit(ch)) {
2929 sb.append(Character.toChars(ch));
2930 }
2931 if (sb.length() == 0)
2932 throw error("named capturing group has 0 length name");
2933 if (ch != '>')
2934 throw error("named capturing group is missing trailing '>'");
2935 return sb.toString();
2936 }
2937
2938 /**
2939 * Parses a group and returns the head node of a set of nodes that process
2940 * the group. Sometimes a double return system is used where the tail is
2941 * returned in root.
2942 */
2943 private Node group0() {
2944 boolean capturingGroup = false;
2945 Node head = null;
2946 Node tail = null;
2947 int save = flags;
2948 int saveTCNCount = topClosureNodes.size();
2949 root = null;
2950 int ch = next();
2951 if (ch == '?') {
2952 ch = skip();
2953 switch (ch) {
2954 case ':': // (?:xxx) pure group
2955 head = createGroup(true);
2956 tail = root;
2957 head.next = expr(tail);
2958 break;
2959 case '=': // (?=xxx) and (?!xxx) lookahead
2960 case '!':
2961 head = createGroup(true);
2962 tail = root;
2963 head.next = expr(tail);
2964 if (ch == '=') {
2965 head = tail = new Pos(head);
2966 } else {
2967 head = tail = new Neg(head);
2968 }
2969 break;
2970 case '>': // (?>xxx) independent group
2971 head = createGroup(true);
2972 tail = root;
2973 head.next = expr(tail);
2974 head = tail = new Ques(head, Qtype.INDEPENDENT);
2975 break;
2976 case '<': // (?<xxx) look behind
2977 ch = read();
2978 if (ASCII.isLower(ch) || ASCII.isUpper(ch)) {
2979 // named captured group
2980 String name = groupname(ch);
2981 if (namedGroups().containsKey(name))
2982 throw error("Named capturing group <" + name
2983 + "> is already defined");
2984 capturingGroup = true;
2985 head = createGroup(false);
2986 tail = root;
2987 namedGroups().put(name, capturingGroupCount-1);
2988 head.next = expr(tail);
2989 break;
2990 }
2991 int start = cursor;
2992 head = createGroup(true);
2993 tail = root;
2994 head.next = expr(tail);
2995 tail.next = lookbehindEnd;
2996 TreeInfo info = new TreeInfo();
2997 head.study(info);
2998 if (info.maxValid == false) {
2999 throw error("Look-behind group does not have "
3000 + "an obvious maximum length");
3001 }
3002 boolean hasSupplementary = findSupplementary(start, patternLength);
3003 if (ch == '=') {
3004 head = tail = (hasSupplementary ?
3005 new BehindS(head, info.maxLength,
3006 info.minLength) :
3007 new Behind(head, info.maxLength,
3008 info.minLength));
3009 } else if (ch == '!') {
3010 head = tail = (hasSupplementary ?
3011 new NotBehindS(head, info.maxLength,
3012 info.minLength) :
3013 new NotBehind(head, info.maxLength,
3014 info.minLength));
3015 } else {
3016 throw error("Unknown look-behind group");
3017 }
3018 // clear all top-closure-nodes inside lookbehind
3019 if (saveTCNCount < topClosureNodes.size())
3020 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3021 break;
3022 case '$':
3023 case '@':
3024 throw error("Unknown group type");
3025 default: // (?xxx:) inlined match flags
3026 unread();
3027 addFlag();
3028 ch = read();
3029 if (ch == ')') {
3030 return null; // Inline modifier only
3031 }
3032 if (ch != ':') {
3033 throw error("Unknown inline modifier");
3034 }
3035 head = createGroup(true);
3036 tail = root;
3037 head.next = expr(tail);
3038 break;
3039 }
3040 } else { // (xxx) a regular group
3041 capturingGroup = true;
3042 head = createGroup(false);
3043 tail = root;
3044 head.next = expr(tail);
3045 }
3046
3047 accept(')', "Unclosed group");
3048 flags = save;
3049
3050 // Check for quantifiers
3051 Node node = closure(head);
3052 if (node == head) { // No closure
3053 root = tail;
3054 return node; // Dual return
3055 }
3056 if (head == tail) { // Zero length assertion
3057 root = node;
3058 return node; // Dual return
3059 }
3060
3061 // have group closure, clear all inner closure nodes from the
3062 // top list (no backtracking stopper optimization for inner
3063 if (saveTCNCount < topClosureNodes.size())
3064 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3065
3066 if (node instanceof Ques) {
3067 Ques ques = (Ques) node;
3068 if (ques.type == Qtype.POSSESSIVE) {
3069 root = node;
3070 return node;
3071 }
3072 tail.next = new BranchConn();
3073 tail = tail.next;
3074 if (ques.type == Qtype.GREEDY) {
3075 head = new Branch(head, null, tail);
3076 } else { // Reluctant quantifier
3077 head = new Branch(null, head, tail);
3078 }
3079 root = tail;
3080 return head;
3081 } else if (node instanceof Curly) {
3082 Curly curly = (Curly) node;
3083 if (curly.type == Qtype.POSSESSIVE) {
3084 root = node;
3085 return node;
3086 }
3087 // Discover if the group is deterministic
3088 TreeInfo info = new TreeInfo();
3089 if (head.study(info)) { // Deterministic
3090 GroupTail temp = (GroupTail) tail;
3091 head = root = new GroupCurly(head.next, curly.cmin,
3092 curly.cmax, curly.type,
3093 ((GroupTail)tail).localIndex,
3094 ((GroupTail)tail).groupIndex,
3095 capturingGroup);
3096 return head;
3097 } else { // Non-deterministic
3098 int temp = ((GroupHead) head).localIndex;
3099 Loop loop;
3100 if (curly.type == Qtype.GREEDY) {
3101 loop = new Loop(this.localCount, temp);
3102 // add the max_reps greedy to the top-closure-node list
3103 if (curly.cmax == MAX_REPS)
3104 topClosureNodes.add(loop);
3105 } else { // Reluctant Curly
3106 loop = new LazyLoop(this.localCount, temp);
3107 }
3108 Prolog prolog = new Prolog(loop);
3109 this.localCount += 1;
3110 loop.cmin = curly.cmin;
3111 loop.cmax = curly.cmax;
3112 loop.body = head;
3113 tail.next = loop;
3114 root = loop;
3115 return prolog; // Dual return
3116 }
3117 }
3118 throw error("Internal logic error");
3119 }
3120
3121 /**
3122 * Create group head and tail nodes using double return. If the group is
3123 * created with anonymous true then it is a pure group and should not
3124 * affect group counting.
3125 */
3126 private Node createGroup(boolean anonymous) {
3127 int localIndex = localCount++;
3128 int groupIndex = 0;
3129 if (!anonymous)
3130 groupIndex = capturingGroupCount++;
3131 GroupHead head = new GroupHead(localIndex);
3132 root = new GroupTail(localIndex, groupIndex);
3133
3134 // for debug/print only, head.match does NOT need the "tail" info
3135 head.tail = (GroupTail)root;
3136
3137 if (!anonymous && groupIndex < 10)
3138 groupNodes[groupIndex] = head;
3139 return head;
3140 }
3141
3142 @SuppressWarnings("fallthrough")
3143 /**
3144 * Parses inlined match flags and set them appropriately.
3145 */
3146 private void addFlag() {
3147 int ch = peek();
3148 for (;;) {
3149 switch (ch) {
3150 case 'i':
3151 flags |= CASE_INSENSITIVE;
3152 break;
3153 case 'm':
3154 flags |= MULTILINE;
3155 break;
3156 case 's':
3157 flags |= DOTALL;
3158 break;
3159 case 'd':
3160 flags |= UNIX_LINES;
3161 break;
3162 case 'u':
3163 flags |= UNICODE_CASE;
3164 break;
3165 case 'c':
3166 flags |= CANON_EQ;
3167 break;
3168 case 'x':
3169 flags |= COMMENTS;
3170 break;
3171 case 'U':
3172 flags |= (UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3173 break;
3174 case '-': // subFlag then fall through
3175 ch = next();
3176 subFlag();
3177 default:
3178 return;
3179 }
3180 ch = next();
3181 }
3182 }
3183
3184 @SuppressWarnings("fallthrough")
3185 /**
3186 * Parses the second part of inlined match flags and turns off
3187 * flags appropriately.
3188 */
3189 private void subFlag() {
3190 int ch = peek();
3191 for (;;) {
3192 switch (ch) {
3193 case 'i':
3194 flags &= ~CASE_INSENSITIVE;
3195 break;
3196 case 'm':
3197 flags &= ~MULTILINE;
3198 break;
3199 case 's':
3200 flags &= ~DOTALL;
3201 break;
3202 case 'd':
3203 flags &= ~UNIX_LINES;
3204 break;
3205 case 'u':
3206 flags &= ~UNICODE_CASE;
3207 break;
3208 case 'c':
3209 flags &= ~CANON_EQ;
3210 break;
3211 case 'x':
3212 flags &= ~COMMENTS;
3213 break;
3214 case 'U':
3215 flags &= ~(UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3216 break;
3217 default:
3218 return;
3219 }
3220 ch = next();
3221 }
3222 }
3223
3224 static final int MAX_REPS = 0x7FFFFFFF;
3225
3226 static enum Qtype {
3227 GREEDY, LAZY, POSSESSIVE, INDEPENDENT
3228 }
3229
3230 private Node curly(Node prev, int cmin) {
3231 int ch = next();
3232 if (ch == '?') {
3233 next();
3234 return new Curly(prev, cmin, MAX_REPS, Qtype.LAZY);
3235 } else if (ch == '+') {
3236 next();
3237 return new Curly(prev, cmin, MAX_REPS, Qtype.POSSESSIVE);
3238 }
3239 if (prev instanceof BmpCharProperty) {
3240 return new BmpCharPropertyGreedy((BmpCharProperty)prev, cmin);
3241 } else if (prev instanceof CharProperty) {
3242 return new CharPropertyGreedy((CharProperty)prev, cmin);
3243 }
3244 return new Curly(prev, cmin, MAX_REPS, Qtype.GREEDY);
3245 }
3246
3247 /**
3248 * Processes repetition. If the next character peeked is a quantifier
3249 * then new nodes must be appended to handle the repetition.
3250 * Prev could be a single or a group, so it could be a chain of nodes.
3251 */
3252 private Node closure(Node prev) {
3253 Node atom;
3254 int ch = peek();
3255 switch (ch) {
3256 case '?':
3257 ch = next();
3258 if (ch == '?') {
3259 next();
3260 return new Ques(prev, Qtype.LAZY);
3261 } else if (ch == '+') {
3262 next();
3263 return new Ques(prev, Qtype.POSSESSIVE);
3264 }
3265 return new Ques(prev, Qtype.GREEDY);
3266 case '*':
3267 return curly(prev, 0);
3268 case '+':
3269 return curly(prev, 1);
3270 case '{':
3271 ch = temp[cursor+1];
3272 if (ASCII.isDigit(ch)) {
3273 skip();
3274 int cmin = 0;
3275 do {
3276 cmin = cmin * 10 + (ch - '0');
3277 } while (ASCII.isDigit(ch = read()));
3278 int cmax = cmin;
3279 if (ch == ',') {
3280 ch = read();
3281 cmax = MAX_REPS;
3282 if (ch != '}') {
3283 cmax = 0;
3284 while (ASCII.isDigit(ch)) {
3285 cmax = cmax * 10 + (ch - '0');
3286 ch = read();
3287 }
3288 }
3289 }
3290 if (ch != '}')
3291 throw error("Unclosed counted closure");
3292 if (((cmin) | (cmax) | (cmax - cmin)) < 0)
3293 throw error("Illegal repetition range");
3294 Curly curly;
3295 ch = peek();
3296 if (ch == '?') {
3297 next();
3298 curly = new Curly(prev, cmin, cmax, Qtype.LAZY);
3299 } else if (ch == '+') {
3300 next();
3301 curly = new Curly(prev, cmin, cmax, Qtype.POSSESSIVE);
3302 } else {
3303 curly = new Curly(prev, cmin, cmax, Qtype.GREEDY);
3304 }
3305 return curly;
3306 } else {
3307 throw error("Illegal repetition");
3308 }
3309 default:
3310 return prev;
3311 }
3312 }
3313
3314 /**
3315 * Utility method for parsing control escape sequences.
3316 */
3317 private int c() {
3318 if (cursor < patternLength) {
3319 return read() ^ 64;
3320 }
3321 throw error("Illegal control escape sequence");
3322 }
3323
3324 /**
3325 * Utility method for parsing octal escape sequences.
3326 */
3327 private int o() {
3328 int n = read();
3329 if (((n-'0')|('7'-n)) >= 0) {
3330 int m = read();
3331 if (((m-'0')|('7'-m)) >= 0) {
3332 int o = read();
3333 if ((((o-'0')|('7'-o)) >= 0) && (((n-'0')|('3'-n)) >= 0)) {
3334 return (n - '0') * 64 + (m - '0') * 8 + (o - '0');
3335 }
3336 unread();
3337 return (n - '0') * 8 + (m - '0');
3338 }
3339 unread();
3340 return (n - '0');
3341 }
3342 throw error("Illegal octal escape sequence");
3343 }
3344
3345 /**
3346 * Utility method for parsing hexadecimal escape sequences.
3347 */
3348 private int x() {
3349 int n = read();
3350 if (ASCII.isHexDigit(n)) {
3351 int m = read();
3352 if (ASCII.isHexDigit(m)) {
3353 return ASCII.toDigit(n) * 16 + ASCII.toDigit(m);
3354 }
3355 } else if (n == '{' && ASCII.isHexDigit(peek())) {
3356 int ch = 0;
3357 while (ASCII.isHexDigit(n = read())) {
3358 ch = (ch << 4) + ASCII.toDigit(n);
3359 if (ch > Character.MAX_CODE_POINT)
3360 throw error("Hexadecimal codepoint is too big");
3361 }
3362 if (n != '}')
3363 throw error("Unclosed hexadecimal escape sequence");
3364 return ch;
3365 }
3366 throw error("Illegal hexadecimal escape sequence");
3367 }
3368
3369 /**
3370 * Utility method for parsing unicode escape sequences.
3371 */
3372 private int cursor() {
3373 return cursor;
3374 }
3375
3376 private void setcursor(int pos) {
3377 cursor = pos;
3378 }
3379
3380 private int uxxxx() {
3381 int n = 0;
3382 for (int i = 0; i < 4; i++) {
3383 int ch = read();
3384 if (!ASCII.isHexDigit(ch)) {
3385 throw error("Illegal Unicode escape sequence");
3386 }
3387 n = n * 16 + ASCII.toDigit(ch);
3388 }
3389 return n;
3390 }
3391
3392 private int u() {
3393 int n = uxxxx();
3394 if (Character.isHighSurrogate((char)n)) {
3395 int cur = cursor();
3396 if (read() == '\\' && read() == 'u') {
3397 int n2 = uxxxx();
3398 if (Character.isLowSurrogate((char)n2))
3399 return Character.toCodePoint((char)n, (char)n2);
3400 }
3401 setcursor(cur);
3402 }
3403 return n;
3404 }
3405
3406 private int N() {
3407 if (read() == '{') {
3408 int i = cursor;
3409 while (cursor < patternLength && read() != '}') {}
3410 if (cursor > patternLength)
3411 throw error("Unclosed character name escape sequence");
3412 String name = new String(temp, i, cursor - i - 1);
3413 try {
3414 return Character.codePointOf(name);
3415 } catch (IllegalArgumentException x) {
3416 throw error("Unknown character name [" + name + "]");
3417 }
3418 }
3419 throw error("Illegal character name escape sequence");
3420 }
3421
3422 //
3423 // Utility methods for code point support
3424 //
3425 private static final int countChars(CharSequence seq, int index,
3426 int lengthInCodePoints) {
3427 // optimization
3428 if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) {
3429 assert (index >= 0 && index < seq.length());
3430 return 1;
3431 }
3432 int length = seq.length();
3433 int x = index;
3434 if (lengthInCodePoints >= 0) {
3435 assert (index >= 0 && index < length);
3436 for (int i = 0; x < length && i < lengthInCodePoints; i++) {
3437 if (Character.isHighSurrogate(seq.charAt(x++))) {
3438 if (x < length && Character.isLowSurrogate(seq.charAt(x))) {
3439 x++;
3440 }
3441 }
3442 }
3443 return x - index;
3444 }
3445
3446 assert (index >= 0 && index <= length);
3447 if (index == 0) {
3448 return 0;
3449 }
3450 int len = -lengthInCodePoints;
3451 for (int i = 0; x > 0 && i < len; i++) {
3452 if (Character.isLowSurrogate(seq.charAt(--x))) {
3453 if (x > 0 && Character.isHighSurrogate(seq.charAt(x-1))) {
3454 x--;
3455 }
3456 }
3457 }
3458 return index - x;
3459 }
3460
3461 private static final int countCodePoints(CharSequence seq) {
3462 int length = seq.length();
3463 int n = 0;
3464 for (int i = 0; i < length; ) {
3465 n++;
3466 if (Character.isHighSurrogate(seq.charAt(i++))) {
3467 if (i < length && Character.isLowSurrogate(seq.charAt(i))) {
3468 i++;
3469 }
3470 }
3471 }
3472 return n;
3473 }
3474
3475 /**
3476 * Creates a bit vector for matching Latin-1 values. A normal BitClass
3477 * never matches values above Latin-1, and a complemented BitClass always
3478 * matches values above Latin-1.
3479 */
3480 static final class BitClass extends BmpCharProperty {
3481 final boolean[] bits;
3482 BitClass() {
3483 this(new boolean[256]);
3484 }
3485 private BitClass(boolean[] bits) {
3486 super( ch -> ch < 256 && bits[ch]);
3487 this.bits = bits;
3488 }
3489 BitClass add(int c, int flags) {
3490 assert c >= 0 && c <= 255;
3491 if ((flags & CASE_INSENSITIVE) != 0) {
3492 if (ASCII.isAscii(c)) {
3493 bits[ASCII.toUpper(c)] = true;
3494 bits[ASCII.toLower(c)] = true;
3495 } else if ((flags & UNICODE_CASE) != 0) {
3496 bits[Character.toLowerCase(c)] = true;
3497 bits[Character.toUpperCase(c)] = true;
3498 }
3499 }
3500 bits[c] = true;
3501 return this;
3502 }
3503 }
3504
3505 /**
3506 * Utility method for creating a string slice matcher.
3507 */
3508 private Node newSlice(int[] buf, int count, boolean hasSupplementary) {
3509 int[] tmp = new int[count];
3510 if (has(CASE_INSENSITIVE)) {
3511 if (has(UNICODE_CASE)) {
3512 for (int i = 0; i < count; i++) {
3513 tmp[i] = Character.toLowerCase(
3514 Character.toUpperCase(buf[i]));
3515 }
3516 return hasSupplementary? new SliceUS(tmp) : new SliceU(tmp);
3517 }
3518 for (int i = 0; i < count; i++) {
3519 tmp[i] = ASCII.toLower(buf[i]);
3520 }
3521 return hasSupplementary? new SliceIS(tmp) : new SliceI(tmp);
3522 }
3523 for (int i = 0; i < count; i++) {
3524 tmp[i] = buf[i];
3525 }
3526 return hasSupplementary ? new SliceS(tmp) : new Slice(tmp);
3527 }
3528
3529 /**
3530 * The following classes are the building components of the object
3531 * tree that represents a compiled regular expression. The object tree
3532 * is made of individual elements that handle constructs in the Pattern.
3533 * Each type of object knows how to match its equivalent construct with
3534 * the match() method.
3535 */
3536
3537 /**
3538 * Base class for all node classes. Subclasses should override the match()
3539 * method as appropriate. This class is an accepting node, so its match()
3540 * always returns true.
3541 */
3542 static class Node extends Object {
3543 Node next;
3544 Node() {
3545 next = Pattern.accept;
3546 }
3547 /**
3548 * This method implements the classic accept node.
3549 */
3550 boolean match(Matcher matcher, int i, CharSequence seq) {
3551 matcher.last = i;
3552 matcher.groups[0] = matcher.first;
3553 matcher.groups[1] = matcher.last;
3554 return true;
3555 }
3556 /**
3557 * This method is good for all zero length assertions.
3558 */
3559 boolean study(TreeInfo info) {
3560 if (next != null) {
3561 return next.study(info);
3562 } else {
3563 return info.deterministic;
3564 }
3565 }
3566 }
3567
3568 static class LastNode extends Node {
3569 /**
3570 * This method implements the classic accept node with
3571 * the addition of a check to see if the match occurred
3572 * using all of the input.
3573 */
3574 boolean match(Matcher matcher, int i, CharSequence seq) {
3575 if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to)
3576 return false;
3577 matcher.last = i;
3578 matcher.groups[0] = matcher.first;
3579 matcher.groups[1] = matcher.last;
3580 return true;
3581 }
3582 }
3583
3584 /**
3585 * Used for REs that can start anywhere within the input string.
3586 * This basically tries to match repeatedly at each spot in the
3587 * input string, moving forward after each try. An anchored search
3588 * or a BnM will bypass this node completely.
3589 */
3590 static class Start extends Node {
3591 int minLength;
3592 Start(Node node) {
3593 this.next = node;
3594 TreeInfo info = new TreeInfo();
3595 next.study(info);
3596 minLength = info.minLength;
3597 }
3598 boolean match(Matcher matcher, int i, CharSequence seq) {
3599 if (i > matcher.to - minLength) {
3600 matcher.hitEnd = true;
3601 return false;
3602 }
3603 int guard = matcher.to - minLength;
3604 for (; i <= guard; i++) {
3605 if (next.match(matcher, i, seq)) {
3606 matcher.first = i;
3607 matcher.groups[0] = matcher.first;
3608 matcher.groups[1] = matcher.last;
3609 return true;
3610 }
3611 }
3612 matcher.hitEnd = true;
3613 return false;
3614 }
3615 boolean study(TreeInfo info) {
3616 next.study(info);
3617 info.maxValid = false;
3618 info.deterministic = false;
3619 return false;
3620 }
3621 }
3622
3623 /*
3624 * StartS supports supplementary characters, including unpaired surrogates.
3625 */
3626 static final class StartS extends Start {
3627 StartS(Node node) {
3628 super(node);
3629 }
3630 boolean match(Matcher matcher, int i, CharSequence seq) {
3631 if (i > matcher.to - minLength) {
3632 matcher.hitEnd = true;
3633 return false;
3634 }
3635 int guard = matcher.to - minLength;
3636 while (i <= guard) {
3637 //if ((ret = next.match(matcher, i, seq)) || i == guard)
3638 if (next.match(matcher, i, seq)) {
3639 matcher.first = i;
3640 matcher.groups[0] = matcher.first;
3641 matcher.groups[1] = matcher.last;
3642 return true;
3643 }
3644 if (i == guard)
3645 break;
3646 // Optimization to move to the next character. This is
3647 // faster than countChars(seq, i, 1).
3648 if (Character.isHighSurrogate(seq.charAt(i++))) {
3649 if (i < seq.length() &&
3650 Character.isLowSurrogate(seq.charAt(i))) {
3651 i++;
3652 }
3653 }
3654 }
3655 matcher.hitEnd = true;
3656 return false;
3657 }
3658 }
3659
3660 /**
3661 * Node to anchor at the beginning of input. This object implements the
3662 * match for a \A sequence, and the caret anchor will use this if not in
3663 * multiline mode.
3664 */
3665 static final class Begin extends Node {
3666 boolean match(Matcher matcher, int i, CharSequence seq) {
3667 int fromIndex = (matcher.anchoringBounds) ?
3668 matcher.from : 0;
3669 if (i == fromIndex && next.match(matcher, i, seq)) {
3670 matcher.first = i;
3671 matcher.groups[0] = i;
3672 matcher.groups[1] = matcher.last;
3673 return true;
3674 } else {
3675 return false;
3676 }
3677 }
3678 }
3679
3680 /**
3681 * Node to anchor at the end of input. This is the absolute end, so this
3682 * should not match at the last newline before the end as $ will.
3683 */
3684 static final class End extends Node {
3685 boolean match(Matcher matcher, int i, CharSequence seq) {
3686 int endIndex = (matcher.anchoringBounds) ?
3687 matcher.to : matcher.getTextLength();
3688 if (i == endIndex) {
3689 matcher.hitEnd = true;
3690 return next.match(matcher, i, seq);
3691 }
3692 return false;
3693 }
3694 }
3695
3696 /**
3697 * Node to anchor at the beginning of a line. This is essentially the
3698 * object to match for the multiline ^.
3699 */
3700 static final class Caret extends Node {
3701 boolean match(Matcher matcher, int i, CharSequence seq) {
3702 int startIndex = matcher.from;
3703 int endIndex = matcher.to;
3704 if (!matcher.anchoringBounds) {
3705 startIndex = 0;
3706 endIndex = matcher.getTextLength();
3707 }
3708 // Perl does not match ^ at end of input even after newline
3709 if (i == endIndex) {
3710 matcher.hitEnd = true;
3711 return false;
3712 }
3713 if (i > startIndex) {
3714 char ch = seq.charAt(i-1);
3715 if (ch != '\n' && ch != '\r'
3716 && (ch|1) != '\u2029'
3717 && ch != '\u0085' ) {
3718 return false;
3719 }
3720 // Should treat /r/n as one newline
3721 if (ch == '\r' && seq.charAt(i) == '\n')
3722 return false;
3723 }
3724 return next.match(matcher, i, seq);
3725 }
3726 }
3727
3728 /**
3729 * Node to anchor at the beginning of a line when in unixdot mode.
3730 */
3731 static final class UnixCaret extends Node {
3732 boolean match(Matcher matcher, int i, CharSequence seq) {
3733 int startIndex = matcher.from;
3734 int endIndex = matcher.to;
3735 if (!matcher.anchoringBounds) {
3736 startIndex = 0;
3737 endIndex = matcher.getTextLength();
3738 }
3739 // Perl does not match ^ at end of input even after newline
3740 if (i == endIndex) {
3741 matcher.hitEnd = true;
3742 return false;
3743 }
3744 if (i > startIndex) {
3745 char ch = seq.charAt(i-1);
3746 if (ch != '\n') {
3747 return false;
3748 }
3749 }
3750 return next.match(matcher, i, seq);
3751 }
3752 }
3753
3754 /**
3755 * Node to match the location where the last match ended.
3756 * This is used for the \G construct.
3757 */
3758 static final class LastMatch extends Node {
3759 boolean match(Matcher matcher, int i, CharSequence seq) {
3760 if (i != matcher.oldLast)
3761 return false;
3762 return next.match(matcher, i, seq);
3763 }
3764 }
3765
3766 /**
3767 * Node to anchor at the end of a line or the end of input based on the
3768 * multiline mode.
3769 *
3770 * When not in multiline mode, the $ can only match at the very end
3771 * of the input, unless the input ends in a line terminator in which
3772 * it matches right before the last line terminator.
3773 *
3774 * Note that \r\n is considered an atomic line terminator.
3775 *
3776 * Like ^ the $ operator matches at a position, it does not match the
3777 * line terminators themselves.
3778 */
3779 static final class Dollar extends Node {
3780 boolean multiline;
3781 Dollar(boolean mul) {
3782 multiline = mul;
3783 }
3784 boolean match(Matcher matcher, int i, CharSequence seq) {
3785 int endIndex = (matcher.anchoringBounds) ?
3786 matcher.to : matcher.getTextLength();
3787 if (!multiline) {
3788 if (i < endIndex - 2)
3789 return false;
3790 if (i == endIndex - 2) {
3791 char ch = seq.charAt(i);
3792 if (ch != '\r')
3793 return false;
3794 ch = seq.charAt(i + 1);
3795 if (ch != '\n')
3796 return false;
3797 }
3798 }
3799 // Matches before any line terminator; also matches at the
3800 // end of input
3801 // Before line terminator:
3802 // If multiline, we match here no matter what
3803 // If not multiline, fall through so that the end
3804 // is marked as hit; this must be a /r/n or a /n
3805 // at the very end so the end was hit; more input
3806 // could make this not match here
3807 if (i < endIndex) {
3808 char ch = seq.charAt(i);
3809 if (ch == '\n') {
3810 // No match between \r\n
3811 if (i > 0 && seq.charAt(i-1) == '\r')
3812 return false;
3813 if (multiline)
3814 return next.match(matcher, i, seq);
3815 } else if (ch == '\r' || ch == '\u0085' ||
3816 (ch|1) == '\u2029') {
3817 if (multiline)
3818 return next.match(matcher, i, seq);
3819 } else { // No line terminator, no match
3820 return false;
3821 }
3822 }
3823 // Matched at current end so hit end
3824 matcher.hitEnd = true;
3825 // If a $ matches because of end of input, then more input
3826 // could cause it to fail!
3827 matcher.requireEnd = true;
3828 return next.match(matcher, i, seq);
3829 }
3830 boolean study(TreeInfo info) {
3831 next.study(info);
3832 return info.deterministic;
3833 }
3834 }
3835
3836 /**
3837 * Node to anchor at the end of a line or the end of input based on the
3838 * multiline mode when in unix lines mode.
3839 */
3840 static final class UnixDollar extends Node {
3841 boolean multiline;
3842 UnixDollar(boolean mul) {
3843 multiline = mul;
3844 }
3845 boolean match(Matcher matcher, int i, CharSequence seq) {
3846 int endIndex = (matcher.anchoringBounds) ?
3847 matcher.to : matcher.getTextLength();
3848 if (i < endIndex) {
3849 char ch = seq.charAt(i);
3850 if (ch == '\n') {
3851 // If not multiline, then only possible to
3852 // match at very end or one before end
3853 if (multiline == false && i != endIndex - 1)
3854 return false;
3855 // If multiline return next.match without setting
3856 // matcher.hitEnd
3857 if (multiline)
3858 return next.match(matcher, i, seq);
3859 } else {
3860 return false;
3861 }
3862 }
3863 // Matching because at the end or 1 before the end;
3864 // more input could change this so set hitEnd
3865 matcher.hitEnd = true;
3866 // If a $ matches because of end of input, then more input
3867 // could cause it to fail!
3868 matcher.requireEnd = true;
3869 return next.match(matcher, i, seq);
3870 }
3871 boolean study(TreeInfo info) {
3872 next.study(info);
3873 return info.deterministic;
3874 }
3875 }
3876
3877 /**
3878 * Node class that matches a Unicode line ending '\R'
3879 */
3880 static final class LineEnding extends Node {
3881 boolean match(Matcher matcher, int i, CharSequence seq) {
3882 // (u+000Du+000A|[u+000Au+000Bu+000Cu+000Du+0085u+2028u+2029])
3883 if (i < matcher.to) {
3884 int ch = seq.charAt(i);
3885 if (ch == 0x0A || ch == 0x0B || ch == 0x0C ||
3886 ch == 0x85 || ch == 0x2028 || ch == 0x2029)
3887 return next.match(matcher, i + 1, seq);
3888 if (ch == 0x0D) {
3889 i++;
3890 if (i < matcher.to && seq.charAt(i) == 0x0A &&
3891 next.match(matcher, i + 1, seq)) {
3892 return true;
3893 }
3894 return next.match(matcher, i, seq);
3895 }
3896 } else {
3897 matcher.hitEnd = true;
3898 }
3899 return false;
3900 }
3901 boolean study(TreeInfo info) {
3902 info.minLength++;
3903 info.maxLength += 2;
3904 return next.study(info);
3905 }
3906 }
3907
3908 /**
3909 * Abstract node class to match one character satisfying some
3910 * boolean property.
3911 */
3912 static class CharProperty extends Node {
3913 CharPredicate predicate;
3914
3915 CharProperty (CharPredicate predicate) {
3916 this.predicate = predicate;
3917 }
3918 boolean match(Matcher matcher, int i, CharSequence seq) {
3919 if (i < matcher.to) {
3920 int ch = Character.codePointAt(seq, i);
3921 return predicate.is(ch) &&
3922 next.match(matcher, i + Character.charCount(ch), seq);
3923 } else {
3924 matcher.hitEnd = true;
3925 return false;
3926 }
3927 }
3928 boolean study(TreeInfo info) {
3929 info.minLength++;
3930 info.maxLength++;
3931 return next.study(info);
3932 }
3933 }
3934
3935 /**
3936 * Optimized version of CharProperty that works only for
3937 * properties never satisfied by Supplementary characters.
3938 */
3939 private static class BmpCharProperty extends CharProperty {
3940 BmpCharProperty (BmpCharPredicate predicate) {
3941 super(predicate);
3942 }
3943 boolean match(Matcher matcher, int i, CharSequence seq) {
3944 if (i < matcher.to) {
3945 return predicate.is(seq.charAt(i)) &&
3946 next.match(matcher, i + 1, seq);
3947 } else {
3948 matcher.hitEnd = true;
3949 return false;
3950 }
3951 }
3952 }
3953
3954 private static class NFCCharProperty extends Node {
3955 CharPredicate predicate;
3956 NFCCharProperty (CharPredicate predicate) {
3957 this.predicate = predicate;
3958 }
3959
3960 boolean match(Matcher matcher, int i, CharSequence seq) {
3961 if (i < matcher.to) {
3962 int ch0 = Character.codePointAt(seq, i);
3963 int n = Character.charCount(ch0);
3964 int j = i + n;
3965 while (j < matcher.to) {
3966 int ch1 = Character.codePointAt(seq, j);
3967 if (Grapheme.isBoundary(ch0, ch1))
3968 break;
3969 ch0 = ch1;
3970 j += Character.charCount(ch1);
3971 }
3972 if (i + n == j) { // single, assume nfc cp
3973 if (predicate.is(ch0))
3974 return next.match(matcher, j, seq);
3975 } else {
3976 while (i + n < j) {
3977 String nfc = Normalizer.normalize(
3978 seq.toString().substring(i, j), Normalizer.Form.NFC);
3979 if (nfc.codePointCount(0, nfc.length()) == 1) {
3980 if (predicate.is(nfc.codePointAt(0)) &&
3981 next.match(matcher, j, seq)) {
3982 return true;
3983 }
3984 }
3985
3986 ch0 = Character.codePointBefore(seq, j);
3987 j -= Character.charCount(ch0);
3988 }
3989 }
3990 if (j < matcher.to)
3991 return false;
3992 }
3993 matcher.hitEnd = true;
3994 return false;
3995 }
3996
3997 boolean study(TreeInfo info) {
3998 info.minLength++;
3999 info.deterministic = false;
4000 return next.study(info);
4001 }
4002 }
4003
4004 /**
4005 * Node class that matches an unicode extended grapheme cluster
4006 */
4007 static class XGrapheme extends Node {
4008 boolean match(Matcher matcher, int i, CharSequence seq) {
4009 if (i < matcher.to) {
4010 int ch0 = Character.codePointAt(seq, i);
4011 i += Character.charCount(ch0);
4012 while (i < matcher.to) {
4013 int ch1 = Character.codePointAt(seq, i);
4014 if (Grapheme.isBoundary(ch0, ch1))
4015 break;
4016 ch0 = ch1;
4017 i += Character.charCount(ch1);
4018 }
4019 return next.match(matcher, i, seq);
4020 }
4021 matcher.hitEnd = true;
4022 return false;
4023 }
4024
4025 boolean study(TreeInfo info) {
4026 info.minLength++;
4027 info.deterministic = false;
4028 return next.study(info);
4029 }
4030 }
4031
4032 /**
4033 * Node class that handles grapheme boundaries
4034 */
4035 static class GraphemeBound extends Node {
4036 boolean match(Matcher matcher, int i, CharSequence seq) {
4037 int startIndex = matcher.from;
4038 int endIndex = matcher.to;
4039 if (matcher.transparentBounds) {
4040 startIndex = 0;
4041 endIndex = matcher.getTextLength();
4042 }
4043 if (i == startIndex) {
4044 return next.match(matcher, i, seq);
4045 }
4046 if (i < endIndex) {
4047 if (Character.isSurrogatePair(seq.charAt(i-1), seq.charAt(i)) ||
4048 !Grapheme.isBoundary(Character.codePointBefore(seq, i),
4049 Character.codePointAt(seq, i))) {
4050 return false;
4051 }
4052 } else {
4053 matcher.hitEnd = true;
4054 matcher.requireEnd = true;
4055 }
4056 return next.match(matcher, i, seq);
4057 }
4058 }
4059
4060 /**
4061 * Base class for all Slice nodes
4062 */
4063 static class SliceNode extends Node {
4064 int[] buffer;
4065 SliceNode(int[] buf) {
4066 buffer = buf;
4067 }
4068 boolean study(TreeInfo info) {
4069 info.minLength += buffer.length;
4070 info.maxLength += buffer.length;
4071 return next.study(info);
4072 }
4073 }
4074
4075 /**
4076 * Node class for a case sensitive/BMP-only sequence of literal
4077 * characters.
4078 */
4079 static class Slice extends SliceNode {
4080 Slice(int[] buf) {
4081 super(buf);
4082 }
4083 boolean match(Matcher matcher, int i, CharSequence seq) {
4084 int[] buf = buffer;
4085 int len = buf.length;
4086 for (int j=0; j<len; j++) {
4087 if ((i+j) >= matcher.to) {
4088 matcher.hitEnd = true;
4089 return false;
4090 }
4091 if (buf[j] != seq.charAt(i+j))
4092 return false;
4093 }
4094 return next.match(matcher, i+len, seq);
4095 }
4096 }
4097
4098 /**
4099 * Node class for a case_insensitive/BMP-only sequence of literal
4100 * characters.
4101 */
4102 static class SliceI extends SliceNode {
4103 SliceI(int[] buf) {
4104 super(buf);
4105 }
4106 boolean match(Matcher matcher, int i, CharSequence seq) {
4107 int[] buf = buffer;
4108 int len = buf.length;
4109 for (int j=0; j<len; j++) {
4110 if ((i+j) >= matcher.to) {
4111 matcher.hitEnd = true;
4112 return false;
4113 }
4114 int c = seq.charAt(i+j);
4115 if (buf[j] != c &&
4116 buf[j] != ASCII.toLower(c))
4117 return false;
4118 }
4119 return next.match(matcher, i+len, seq);
4120 }
4121 }
4122
4123 /**
4124 * Node class for a unicode_case_insensitive/BMP-only sequence of
4125 * literal characters. Uses unicode case folding.
4126 */
4127 static final class SliceU extends SliceNode {
4128 SliceU(int[] buf) {
4129 super(buf);
4130 }
4131 boolean match(Matcher matcher, int i, CharSequence seq) {
4132 int[] buf = buffer;
4133 int len = buf.length;
4134 for (int j=0; j<len; j++) {
4135 if ((i+j) >= matcher.to) {
4136 matcher.hitEnd = true;
4137 return false;
4138 }
4139 int c = seq.charAt(i+j);
4140 if (buf[j] != c &&
4141 buf[j] != Character.toLowerCase(Character.toUpperCase(c)))
4142 return false;
4143 }
4144 return next.match(matcher, i+len, seq);
4145 }
4146 }
4147
4148 /**
4149 * Node class for a case sensitive sequence of literal characters
4150 * including supplementary characters.
4151 */
4152 static final class SliceS extends Slice {
4153 SliceS(int[] buf) {
4154 super(buf);
4155 }
4156 boolean match(Matcher matcher, int i, CharSequence seq) {
4157 int[] buf = buffer;
4158 int x = i;
4159 for (int j = 0; j < buf.length; j++) {
4160 if (x >= matcher.to) {
4161 matcher.hitEnd = true;
4162 return false;
4163 }
4164 int c = Character.codePointAt(seq, x);
4165 if (buf[j] != c)
4166 return false;
4167 x += Character.charCount(c);
4168 if (x > matcher.to) {
4169 matcher.hitEnd = true;
4170 return false;
4171 }
4172 }
4173 return next.match(matcher, x, seq);
4174 }
4175 }
4176
4177 /**
4178 * Node class for a case insensitive sequence of literal characters
4179 * including supplementary characters.
4180 */
4181 static class SliceIS extends SliceNode {
4182 SliceIS(int[] buf) {
4183 super(buf);
4184 }
4185 int toLower(int c) {
4186 return ASCII.toLower(c);
4187 }
4188 boolean match(Matcher matcher, int i, CharSequence seq) {
4189 int[] buf = buffer;
4190 int x = i;
4191 for (int j = 0; j < buf.length; j++) {
4192 if (x >= matcher.to) {
4193 matcher.hitEnd = true;
4194 return false;
4195 }
4196 int c = Character.codePointAt(seq, x);
4197 if (buf[j] != c && buf[j] != toLower(c))
4198 return false;
4199 x += Character.charCount(c);
4200 if (x > matcher.to) {
4201 matcher.hitEnd = true;
4202 return false;
4203 }
4204 }
4205 return next.match(matcher, x, seq);
4206 }
4207 }
4208
4209 /**
4210 * Node class for a case insensitive sequence of literal characters.
4211 * Uses unicode case folding.
4212 */
4213 static final class SliceUS extends SliceIS {
4214 SliceUS(int[] buf) {
4215 super(buf);
4216 }
4217 int toLower(int c) {
4218 return Character.toLowerCase(Character.toUpperCase(c));
4219 }
4220 }
4221
4222 /**
4223 * The 0 or 1 quantifier. This one class implements all three types.
4224 */
4225 static final class Ques extends Node {
4226 Node atom;
4227 Qtype type;
4228 Ques(Node node, Qtype type) {
4229 this.atom = node;
4230 this.type = type;
4231 }
4232 boolean match(Matcher matcher, int i, CharSequence seq) {
4233 switch (type) {
4234 case GREEDY:
4235 return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq))
4236 || next.match(matcher, i, seq);
4237 case LAZY:
4238 return next.match(matcher, i, seq)
4239 || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq));
4240 case POSSESSIVE:
4241 if (atom.match(matcher, i, seq)) i = matcher.last;
4242 return next.match(matcher, i, seq);
4243 default:
4244 return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq);
4245 }
4246 }
4247 boolean study(TreeInfo info) {
4248 if (type != Qtype.INDEPENDENT) {
4249 int minL = info.minLength;
4250 atom.study(info);
4251 info.minLength = minL;
4252 info.deterministic = false;
4253 return next.study(info);
4254 } else {
4255 atom.study(info);
4256 return next.study(info);
4257 }
4258 }
4259 }
4260
4261 /**
4262 * Handles the greedy style repetition with the minimum either be
4263 * 0 or 1 and the maximum be MAX_REPS, for * and + quantifier.
4264 */
4265 static class CharPropertyGreedy extends Node {
4266 final CharPredicate predicate;
4267 final int cmin;
4268
4269 CharPropertyGreedy(CharProperty cp, int cmin) {
4270 this.predicate = cp.predicate;
4271 this.cmin = cmin;
4272 }
4273 boolean match(Matcher matcher, int i, CharSequence seq) {
4274 int n = 0;
4275 int to = matcher.to;
4276 // greedy, all the way down
4277 while (i < to) {
4278 int ch = Character.codePointAt(seq, i);
4279 if (!predicate.is(ch))
4280 break;
4281 i += Character.charCount(ch);
4282 n++;
4283 }
4284 if (i >= to) {
4285 matcher.hitEnd = true;
4286 }
4287 while (n >= cmin) {
4288 if (next.match(matcher, i, seq))
4289 return true;
4290 if (n == cmin)
4291 return false;
4292 // backing off if match fails
4293 int ch = Character.codePointBefore(seq, i);
4294 i -= Character.charCount(ch);
4295 n--;
4296 }
4297 return false;
4298 }
4299
4300 boolean study(TreeInfo info) {
4301 info.minLength += cmin;
4302 if (info.maxValid) {
4303 info.maxLength += MAX_REPS;
4304 }
4305 info.deterministic = false;
4306 return next.study(info);
4307 }
4308 }
4309
4310 static final class BmpCharPropertyGreedy extends CharPropertyGreedy {
4311
4312 BmpCharPropertyGreedy(BmpCharProperty bcp, int cmin) {
4313 super(bcp, cmin);
4314 }
4315
4316 boolean match(Matcher matcher, int i, CharSequence seq) {
4317 int n = 0;
4318 int to = matcher.to;
4319 while (i < to && predicate.is(seq.charAt(i))) {
4320 i++; n++;
4321 }
4322 if (i >= to) {
4323 matcher.hitEnd = true;
4324 }
4325 while (n >= cmin) {
4326 if (next.match(matcher, i, seq))
4327 return true;
4328 i--; n--; // backing off if match fails
4329 }
4330 return false;
4331 }
4332 }
4333
4334 /**
4335 * Handles the curly-brace style repetition with a specified minimum and
4336 * maximum occurrences. The * quantifier is handled as a special case.
4337 * This class handles the three types.
4338 */
4339 static final class Curly extends Node {
4340 Node atom;
4341 Qtype type;
4342 int cmin;
4343 int cmax;
4344
4345 Curly(Node node, int cmin, int cmax, Qtype type) {
4346 this.atom = node;
4347 this.type = type;
4348 this.cmin = cmin;
4349 this.cmax = cmax;
4350 }
4351 boolean match(Matcher matcher, int i, CharSequence seq) {
4352 int j;
4353 for (j = 0; j < cmin; j++) {
4354 if (atom.match(matcher, i, seq)) {
4355 i = matcher.last;
4356 continue;
4357 }
4358 return false;
4359 }
4360 if (type == Qtype.GREEDY)
4361 return match0(matcher, i, j, seq);
4362 else if (type == Qtype.LAZY)
4363 return match1(matcher, i, j, seq);
4364 else
4365 return match2(matcher, i, j, seq);
4366 }
4367 // Greedy match.
4368 // i is the index to start matching at
4369 // j is the number of atoms that have matched
4370 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4371 if (j >= cmax) {
4372 // We have matched the maximum... continue with the rest of
4373 // the regular expression
4374 return next.match(matcher, i, seq);
4375 }
4376 int backLimit = j;
4377 while (atom.match(matcher, i, seq)) {
4378 // k is the length of this match
4379 int k = matcher.last - i;
4380 if (k == 0) // Zero length match
4381 break;
4382 // Move up index and number matched
4383 i = matcher.last;
4384 j++;
4385 // We are greedy so match as many as we can
4386 while (j < cmax) {
4387 if (!atom.match(matcher, i, seq))
4388 break;
4389 if (i + k != matcher.last) {
4390 if (match0(matcher, matcher.last, j+1, seq))
4391 return true;
4392 break;
4393 }
4394 i += k;
4395 j++;
4396 }
4397 // Handle backing off if match fails
4398 while (j >= backLimit) {
4399 if (next.match(matcher, i, seq))
4400 return true;
4401 i -= k;
4402 j--;
4403 }
4404 return false;
4405 }
4406 return next.match(matcher, i, seq);
4407 }
4408 // Reluctant match. At this point, the minimum has been satisfied.
4409 // i is the index to start matching at
4410 // j is the number of atoms that have matched
4411 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4412 for (;;) {
4413 // Try finishing match without consuming any more
4414 if (next.match(matcher, i, seq))
4415 return true;
4416 // At the maximum, no match found
4417 if (j >= cmax)
4418 return false;
4419 // Okay, must try one more atom
4420 if (!atom.match(matcher, i, seq))
4421 return false;
4422 // If we haven't moved forward then must break out
4423 if (i == matcher.last)
4424 return false;
4425 // Move up index and number matched
4426 i = matcher.last;
4427 j++;
4428 }
4429 }
4430 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4431 for (; j < cmax; j++) {
4432 if (!atom.match(matcher, i, seq))
4433 break;
4434 if (i == matcher.last)
4435 break;
4436 i = matcher.last;
4437 }
4438 return next.match(matcher, i, seq);
4439 }
4440 boolean study(TreeInfo info) {
4441 // Save original info
4442 int minL = info.minLength;
4443 int maxL = info.maxLength;
4444 boolean maxV = info.maxValid;
4445 boolean detm = info.deterministic;
4446 info.reset();
4447
4448 atom.study(info);
4449
4450 int temp = info.minLength * cmin + minL;
4451 if (temp < minL) {
4452 temp = 0xFFFFFFF; // arbitrary large number
4453 }
4454 info.minLength = temp;
4455
4456 if (maxV & info.maxValid) {
4457 temp = info.maxLength * cmax + maxL;
4458 info.maxLength = temp;
4459 if (temp < maxL) {
4460 info.maxValid = false;
4461 }
4462 } else {
4463 info.maxValid = false;
4464 }
4465
4466 if (info.deterministic && cmin == cmax)
4467 info.deterministic = detm;
4468 else
4469 info.deterministic = false;
4470 return next.study(info);
4471 }
4472 }
4473
4474 /**
4475 * Handles the curly-brace style repetition with a specified minimum and
4476 * maximum occurrences in deterministic cases. This is an iterative
4477 * optimization over the Prolog and Loop system which would handle this
4478 * in a recursive way. The * quantifier is handled as a special case.
4479 * If capture is true then this class saves group settings and ensures
4480 * that groups are unset when backing off of a group match.
4481 */
4482 static final class GroupCurly extends Node {
4483 Node atom;
4484 Qtype type;
4485 int cmin;
4486 int cmax;
4487 int localIndex;
4488 int groupIndex;
4489 boolean capture;
4490
4491 GroupCurly(Node node, int cmin, int cmax, Qtype type, int local,
4492 int group, boolean capture) {
4493 this.atom = node;
4494 this.type = type;
4495 this.cmin = cmin;
4496 this.cmax = cmax;
4497 this.localIndex = local;
4498 this.groupIndex = group;
4499 this.capture = capture;
4500 }
4501 boolean match(Matcher matcher, int i, CharSequence seq) {
4502 int[] groups = matcher.groups;
4503 int[] locals = matcher.locals;
4504 int save0 = locals[localIndex];
4505 int save1 = 0;
4506 int save2 = 0;
4507
4508 if (capture) {
4509 save1 = groups[groupIndex];
4510 save2 = groups[groupIndex+1];
4511 }
4512
4513 // Notify GroupTail there is no need to setup group info
4514 // because it will be set here
4515 locals[localIndex] = -1;
4516
4517 boolean ret = true;
4518 for (int j = 0; j < cmin; j++) {
4519 if (atom.match(matcher, i, seq)) {
4520 if (capture) {
4521 groups[groupIndex] = i;
4522 groups[groupIndex+1] = matcher.last;
4523 }
4524 i = matcher.last;
4525 } else {
4526 ret = false;
4527 break;
4528 }
4529 }
4530 if (ret) {
4531 if (type == Qtype.GREEDY) {
4532 ret = match0(matcher, i, cmin, seq);
4533 } else if (type == Qtype.LAZY) {
4534 ret = match1(matcher, i, cmin, seq);
4535 } else {
4536 ret = match2(matcher, i, cmin, seq);
4537 }
4538 }
4539 if (!ret) {
4540 locals[localIndex] = save0;
4541 if (capture) {
4542 groups[groupIndex] = save1;
4543 groups[groupIndex+1] = save2;
4544 }
4545 }
4546 return ret;
4547 }
4548 // Aggressive group match
4549 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4550 // don't back off passing the starting "j"
4551 int min = j;
4552 int[] groups = matcher.groups;
4553 int save0 = 0;
4554 int save1 = 0;
4555 if (capture) {
4556 save0 = groups[groupIndex];
4557 save1 = groups[groupIndex+1];
4558 }
4559 for (;;) {
4560 if (j >= cmax)
4561 break;
4562 if (!atom.match(matcher, i, seq))
4563 break;
4564 int k = matcher.last - i;
4565 if (k <= 0) {
4566 if (capture) {
4567 groups[groupIndex] = i;
4568 groups[groupIndex+1] = i + k;
4569 }
4570 i = i + k;
4571 break;
4572 }
4573 for (;;) {
4574 if (capture) {
4575 groups[groupIndex] = i;
4576 groups[groupIndex+1] = i + k;
4577 }
4578 i = i + k;
4579 if (++j >= cmax)
4580 break;
4581 if (!atom.match(matcher, i, seq))
4582 break;
4583 if (i + k != matcher.last) {
4584 if (match0(matcher, i, j, seq))
4585 return true;
4586 break;
4587 }
4588 }
4589 while (j > min) {
4590 if (next.match(matcher, i, seq)) {
4591 if (capture) {
4592 groups[groupIndex+1] = i;
4593 groups[groupIndex] = i - k;
4594 }
4595 return true;
4596 }
4597 // backing off
4598 i = i - k;
4599 if (capture) {
4600 groups[groupIndex+1] = i;
4601 groups[groupIndex] = i - k;
4602 }
4603 j--;
4604
4605 }
4606 break;
4607 }
4608 if (capture) {
4609 groups[groupIndex] = save0;
4610 groups[groupIndex+1] = save1;
4611 }
4612 return next.match(matcher, i, seq);
4613 }
4614 // Reluctant matching
4615 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4616 for (;;) {
4617 if (next.match(matcher, i, seq))
4618 return true;
4619 if (j >= cmax)
4620 return false;
4621 if (!atom.match(matcher, i, seq))
4622 return false;
4623 if (i == matcher.last)
4624 return false;
4625 if (capture) {
4626 matcher.groups[groupIndex] = i;
4627 matcher.groups[groupIndex+1] = matcher.last;
4628 }
4629 i = matcher.last;
4630 j++;
4631 }
4632 }
4633 // Possessive matching
4634 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4635 for (; j < cmax; j++) {
4636 if (!atom.match(matcher, i, seq)) {
4637 break;
4638 }
4639 if (capture) {
4640 matcher.groups[groupIndex] = i;
4641 matcher.groups[groupIndex+1] = matcher.last;
4642 }
4643 if (i == matcher.last) {
4644 break;
4645 }
4646 i = matcher.last;
4647 }
4648 return next.match(matcher, i, seq);
4649 }
4650 boolean study(TreeInfo info) {
4651 // Save original info
4652 int minL = info.minLength;
4653 int maxL = info.maxLength;
4654 boolean maxV = info.maxValid;
4655 boolean detm = info.deterministic;
4656 info.reset();
4657
4658 atom.study(info);
4659
4660 int temp = info.minLength * cmin + minL;
4661 if (temp < minL) {
4662 temp = 0xFFFFFFF; // Arbitrary large number
4663 }
4664 info.minLength = temp;
4665
4666 if (maxV & info.maxValid) {
4667 temp = info.maxLength * cmax + maxL;
4668 info.maxLength = temp;
4669 if (temp < maxL) {
4670 info.maxValid = false;
4671 }
4672 } else {
4673 info.maxValid = false;
4674 }
4675
4676 if (info.deterministic && cmin == cmax) {
4677 info.deterministic = detm;
4678 } else {
4679 info.deterministic = false;
4680 }
4681 return next.study(info);
4682 }
4683 }
4684
4685 /**
4686 * A Guard node at the end of each atom node in a Branch. It
4687 * serves the purpose of chaining the "match" operation to
4688 * "next" but not the "study", so we can collect the TreeInfo
4689 * of each atom node without including the TreeInfo of the
4690 * "next".
4691 */
4692 static final class BranchConn extends Node {
4693 BranchConn() {};
4694 boolean match(Matcher matcher, int i, CharSequence seq) {
4695 return next.match(matcher, i, seq);
4696 }
4697 boolean study(TreeInfo info) {
4698 return info.deterministic;
4699 }
4700 }
4701
4702 /**
4703 * Handles the branching of alternations. Note this is also used for
4704 * the ? quantifier to branch between the case where it matches once
4705 * and where it does not occur.
4706 */
4707 static final class Branch extends Node {
4708 Node[] atoms = new Node[2];
4709 int size = 2;
4710 Node conn;
4711 Branch(Node first, Node second, Node branchConn) {
4712 conn = branchConn;
4713 atoms[0] = first;
4714 atoms[1] = second;
4715 }
4716
4717 void add(Node node) {
4718 if (size >= atoms.length) {
4719 Node[] tmp = new Node[atoms.length*2];
4720 System.arraycopy(atoms, 0, tmp, 0, atoms.length);
4721 atoms = tmp;
4722 }
4723 atoms[size++] = node;
4724 }
4725
4726 boolean match(Matcher matcher, int i, CharSequence seq) {
4727 for (int n = 0; n < size; n++) {
4728 if (atoms[n] == null) {
4729 if (conn.next.match(matcher, i, seq))
4730 return true;
4731 } else if (atoms[n].match(matcher, i, seq)) {
4732 return true;
4733 }
4734 }
4735 return false;
4736 }
4737
4738 boolean study(TreeInfo info) {
4739 int minL = info.minLength;
4740 int maxL = info.maxLength;
4741 boolean maxV = info.maxValid;
4742
4743 int minL2 = Integer.MAX_VALUE; //arbitrary large enough num
4744 int maxL2 = -1;
4745 for (int n = 0; n < size; n++) {
4746 info.reset();
4747 if (atoms[n] != null)
4748 atoms[n].study(info);
4749 minL2 = Math.min(minL2, info.minLength);
4750 maxL2 = Math.max(maxL2, info.maxLength);
4751 maxV = (maxV & info.maxValid);
4752 }
4753
4754 minL += minL2;
4755 maxL += maxL2;
4756
4757 info.reset();
4758 conn.next.study(info);
4759
4760 info.minLength += minL;
4761 info.maxLength += maxL;
4762 info.maxValid &= maxV;
4763 info.deterministic = false;
4764 return false;
4765 }
4766 }
4767
4768 /**
4769 * The GroupHead saves the location where the group begins in the locals
4770 * and restores them when the match is done.
4771 *
4772 * The matchRef is used when a reference to this group is accessed later
4773 * in the expression. The locals will have a negative value in them to
4774 * indicate that we do not want to unset the group if the reference
4775 * doesn't match.
4776 */
4777 static final class GroupHead extends Node {
4778 int localIndex;
4779 GroupTail tail; // for debug/print only, match does not need to know
4780 GroupHead(int localCount) {
4781 localIndex = localCount;
4782 }
4783 boolean match(Matcher matcher, int i, CharSequence seq) {
4784 int save = matcher.locals[localIndex];
4785 matcher.locals[localIndex] = i;
4786 boolean ret = next.match(matcher, i, seq);
4787 matcher.locals[localIndex] = save;
4788 return ret;
4789 }
4790 boolean matchRef(Matcher matcher, int i, CharSequence seq) {
4791 int save = matcher.locals[localIndex];
4792 matcher.locals[localIndex] = ~i; // HACK
4793 boolean ret = next.match(matcher, i, seq);
4794 matcher.locals[localIndex] = save;
4795 return ret;
4796 }
4797 }
4798
4799 /**
4800 * Recursive reference to a group in the regular expression. It calls
4801 * matchRef because if the reference fails to match we would not unset
4802 * the group.
4803 */
4804 static final class GroupRef extends Node {
4805 GroupHead head;
4806 GroupRef(GroupHead head) {
4807 this.head = head;
4808 }
4809 boolean match(Matcher matcher, int i, CharSequence seq) {
4810 return head.matchRef(matcher, i, seq)
4811 && next.match(matcher, matcher.last, seq);
4812 }
4813 boolean study(TreeInfo info) {
4814 info.maxValid = false;
4815 info.deterministic = false;
4816 return next.study(info);
4817 }
4818 }
4819
4820 /**
4821 * The GroupTail handles the setting of group beginning and ending
4822 * locations when groups are successfully matched. It must also be able to
4823 * unset groups that have to be backed off of.
4824 *
4825 * The GroupTail node is also used when a previous group is referenced,
4826 * and in that case no group information needs to be set.
4827 */
4828 static final class GroupTail extends Node {
4829 int localIndex;
4830 int groupIndex;
4831 GroupTail(int localCount, int groupCount) {
4832 localIndex = localCount;
4833 groupIndex = groupCount + groupCount;
4834 }
4835 boolean match(Matcher matcher, int i, CharSequence seq) {
4836 int tmp = matcher.locals[localIndex];
4837 if (tmp >= 0) { // This is the normal group case.
4838 // Save the group so we can unset it if it
4839 // backs off of a match.
4840 int groupStart = matcher.groups[groupIndex];
4841 int groupEnd = matcher.groups[groupIndex+1];
4842
4843 matcher.groups[groupIndex] = tmp;
4844 matcher.groups[groupIndex+1] = i;
4845 if (next.match(matcher, i, seq)) {
4846 return true;
4847 }
4848 matcher.groups[groupIndex] = groupStart;
4849 matcher.groups[groupIndex+1] = groupEnd;
4850 return false;
4851 } else {
4852 // This is a group reference case. We don't need to save any
4853 // group info because it isn't really a group.
4854 matcher.last = i;
4855 return true;
4856 }
4857 }
4858 }
4859
4860 /**
4861 * This sets up a loop to handle a recursive quantifier structure.
4862 */
4863 static final class Prolog extends Node {
4864 Loop loop;
4865 Prolog(Loop loop) {
4866 this.loop = loop;
4867 }
4868 boolean match(Matcher matcher, int i, CharSequence seq) {
4869 return loop.matchInit(matcher, i, seq);
4870 }
4871 boolean study(TreeInfo info) {
4872 return loop.study(info);
4873 }
4874 }
4875
4876 /**
4877 * Handles the repetition count for a greedy Curly. The matchInit
4878 * is called from the Prolog to save the index of where the group
4879 * beginning is stored. A zero length group check occurs in the
4880 * normal match but is skipped in the matchInit.
4881 */
4882 static class Loop extends Node {
4883 Node body;
4884 int countIndex; // local count index in matcher locals
4885 int beginIndex; // group beginning index
4886 int cmin, cmax;
4887 int posIndex;
4888 Loop(int countIndex, int beginIndex) {
4889 this.countIndex = countIndex;
4890 this.beginIndex = beginIndex;
4891 this.posIndex = -1;
4892 }
4893 boolean match(Matcher matcher, int i, CharSequence seq) {
4894 // Avoid infinite loop in zero-length case.
4895 if (i > matcher.locals[beginIndex]) {
4896 int count = matcher.locals[countIndex];
4897
4898 // This block is for before we reach the minimum
4899 // iterations required for the loop to match
4900 if (count < cmin) {
4901 matcher.locals[countIndex] = count + 1;
4902 boolean b = body.match(matcher, i, seq);
4903 // If match failed we must backtrack, so
4904 // the loop count should NOT be incremented
4905 if (!b)
4906 matcher.locals[countIndex] = count;
4907 // Return success or failure since we are under
4908 // minimum
4909 return b;
4910 }
4911 // This block is for after we have the minimum
4912 // iterations required for the loop to match
4913 if (count < cmax) {
4914 // Let's check if we have already tried and failed
4915 // at this starting position "i" in the past.
4916 // If yes, then just return false wihtout trying
4917 // again, to stop the exponential backtracking.
4918 if (posIndex != -1 &&
4919 matcher.localsPos[posIndex].contains(i)) {
4920 return next.match(matcher, i, seq);
4921 }
4922 matcher.locals[countIndex] = count + 1;
4923 boolean b = body.match(matcher, i, seq);
4924 // If match failed we must backtrack, so
4925 // the loop count should NOT be incremented
4926 if (b)
4927 return true;
4928 matcher.locals[countIndex] = count;
4929 // save the failed position
4930 if (posIndex != -1) {
4931 matcher.localsPos[posIndex].add(i);
4932 }
4933 }
4934 }
4935 return next.match(matcher, i, seq);
4936 }
4937 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4938 int save = matcher.locals[countIndex];
4939 boolean ret = false;
4940 if (posIndex != -1 && matcher.localsPos[posIndex] == null) {
4941 matcher.localsPos[posIndex] = new IntHashSet();
4942 }
4943 if (0 < cmin) {
4944 matcher.locals[countIndex] = 1;
4945 ret = body.match(matcher, i, seq);
4946 } else if (0 < cmax) {
4947 matcher.locals[countIndex] = 1;
4948 ret = body.match(matcher, i, seq);
4949 if (ret == false)
4950 ret = next.match(matcher, i, seq);
4951 } else {
4952 ret = next.match(matcher, i, seq);
4953 }
4954 matcher.locals[countIndex] = save;
4955 return ret;
4956 }
4957 boolean study(TreeInfo info) {
4958 info.maxValid = false;
4959 info.deterministic = false;
4960 return false;
4961 }
4962 }
4963
4964 /**
4965 * Handles the repetition count for a reluctant Curly. The matchInit
4966 * is called from the Prolog to save the index of where the group
4967 * beginning is stored. A zero length group check occurs in the
4968 * normal match but is skipped in the matchInit.
4969 */
4970 static final class LazyLoop extends Loop {
4971 LazyLoop(int countIndex, int beginIndex) {
4972 super(countIndex, beginIndex);
4973 }
4974 boolean match(Matcher matcher, int i, CharSequence seq) {
4975 // Check for zero length group
4976 if (i > matcher.locals[beginIndex]) {
4977 int count = matcher.locals[countIndex];
4978 if (count < cmin) {
4979 matcher.locals[countIndex] = count + 1;
4980 boolean result = body.match(matcher, i, seq);
4981 // If match failed we must backtrack, so
4982 // the loop count should NOT be incremented
4983 if (!result)
4984 matcher.locals[countIndex] = count;
4985 return result;
4986 }
4987 if (next.match(matcher, i, seq))
4988 return true;
4989 if (count < cmax) {
4990 matcher.locals[countIndex] = count + 1;
4991 boolean result = body.match(matcher, i, seq);
4992 // If match failed we must backtrack, so
4993 // the loop count should NOT be incremented
4994 if (!result)
4995 matcher.locals[countIndex] = count;
4996 return result;
4997 }
4998 return false;
4999 }
5000 return next.match(matcher, i, seq);
5001 }
5002 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
5003 int save = matcher.locals[countIndex];
5004 boolean ret = false;
5005 if (0 < cmin) {
5006 matcher.locals[countIndex] = 1;
5007 ret = body.match(matcher, i, seq);
5008 } else if (next.match(matcher, i, seq)) {
5009 ret = true;
5010 } else if (0 < cmax) {
5011 matcher.locals[countIndex] = 1;
5012 ret = body.match(matcher, i, seq);
5013 }
5014 matcher.locals[countIndex] = save;
5015 return ret;
5016 }
5017 boolean study(TreeInfo info) {
5018 info.maxValid = false;
5019 info.deterministic = false;
5020 return false;
5021 }
5022 }
5023
5024 /**
5025 * Refers to a group in the regular expression. Attempts to match
5026 * whatever the group referred to last matched.
5027 */
5028 static class BackRef extends Node {
5029 int groupIndex;
5030 BackRef(int groupCount) {
5031 super();
5032 groupIndex = groupCount + groupCount;
5033 }
5034 boolean match(Matcher matcher, int i, CharSequence seq) {
5035 int j = matcher.groups[groupIndex];
5036 int k = matcher.groups[groupIndex+1];
5037
5038 int groupSize = k - j;
5039 // If the referenced group didn't match, neither can this
5040 if (j < 0)
5041 return false;
5042
5043 // If there isn't enough input left no match
5044 if (i + groupSize > matcher.to) {
5045 matcher.hitEnd = true;
5046 return false;
5047 }
5048 // Check each new char to make sure it matches what the group
5049 // referenced matched last time around
5050 for (int index=0; index<groupSize; index++)
5051 if (seq.charAt(i+index) != seq.charAt(j+index))
5052 return false;
5053
5054 return next.match(matcher, i+groupSize, seq);
5055 }
5056 boolean study(TreeInfo info) {
5057 info.maxValid = false;
5058 return next.study(info);
5059 }
5060 }
5061
5062 static class CIBackRef extends Node {
5063 int groupIndex;
5064 boolean doUnicodeCase;
5065 CIBackRef(int groupCount, boolean doUnicodeCase) {
5066 super();
5067 groupIndex = groupCount + groupCount;
5068 this.doUnicodeCase = doUnicodeCase;
5069 }
5070 boolean match(Matcher matcher, int i, CharSequence seq) {
5071 int j = matcher.groups[groupIndex];
5072 int k = matcher.groups[groupIndex+1];
5073
5074 int groupSize = k - j;
5075
5076 // If the referenced group didn't match, neither can this
5077 if (j < 0)
5078 return false;
5079
5080 // If there isn't enough input left no match
5081 if (i + groupSize > matcher.to) {
5082 matcher.hitEnd = true;
5083 return false;
5084 }
5085
5086 // Check each new char to make sure it matches what the group
5087 // referenced matched last time around
5088 int x = i;
5089 for (int index=0; index<groupSize; index++) {
5090 int c1 = Character.codePointAt(seq, x);
5091 int c2 = Character.codePointAt(seq, j);
5092 if (c1 != c2) {
5093 if (doUnicodeCase) {
5094 int cc1 = Character.toUpperCase(c1);
5095 int cc2 = Character.toUpperCase(c2);
5096 if (cc1 != cc2 &&
5097 Character.toLowerCase(cc1) !=
5098 Character.toLowerCase(cc2))
5099 return false;
5100 } else {
5101 if (ASCII.toLower(c1) != ASCII.toLower(c2))
5102 return false;
5103 }
5104 }
5105 x += Character.charCount(c1);
5106 j += Character.charCount(c2);
5107 }
5108
5109 return next.match(matcher, i+groupSize, seq);
5110 }
5111 boolean study(TreeInfo info) {
5112 info.maxValid = false;
5113 return next.study(info);
5114 }
5115 }
5116
5117 /**
5118 * Searches until the next instance of its atom. This is useful for
5119 * finding the atom efficiently without passing an instance of it
5120 * (greedy problem) and without a lot of wasted search time (reluctant
5121 * problem).
5122 */
5123 static final class First extends Node {
5124 Node atom;
5125 First(Node node) {
5126 this.atom = BnM.optimize(node);
5127 }
5128 boolean match(Matcher matcher, int i, CharSequence seq) {
5129 if (atom instanceof BnM) {
5130 return atom.match(matcher, i, seq)
5131 && next.match(matcher, matcher.last, seq);
5132 }
5133 for (;;) {
5134 if (i > matcher.to) {
5135 matcher.hitEnd = true;
5136 return false;
5137 }
5138 if (atom.match(matcher, i, seq)) {
5139 return next.match(matcher, matcher.last, seq);
5140 }
5141 i += countChars(seq, i, 1);
5142 matcher.first++;
5143 }
5144 }
5145 boolean study(TreeInfo info) {
5146 atom.study(info);
5147 info.maxValid = false;
5148 info.deterministic = false;
5149 return next.study(info);
5150 }
5151 }
5152
5153 static final class Conditional extends Node {
5154 Node cond, yes, not;
5155 Conditional(Node cond, Node yes, Node not) {
5156 this.cond = cond;
5157 this.yes = yes;
5158 this.not = not;
5159 }
5160 boolean match(Matcher matcher, int i, CharSequence seq) {
5161 if (cond.match(matcher, i, seq)) {
5162 return yes.match(matcher, i, seq);
5163 } else {
5164 return not.match(matcher, i, seq);
5165 }
5166 }
5167 boolean study(TreeInfo info) {
5168 int minL = info.minLength;
5169 int maxL = info.maxLength;
5170 boolean maxV = info.maxValid;
5171 info.reset();
5172 yes.study(info);
5173
5174 int minL2 = info.minLength;
5175 int maxL2 = info.maxLength;
5176 boolean maxV2 = info.maxValid;
5177 info.reset();
5178 not.study(info);
5179
5180 info.minLength = minL + Math.min(minL2, info.minLength);
5181 info.maxLength = maxL + Math.max(maxL2, info.maxLength);
5182 info.maxValid = (maxV & maxV2 & info.maxValid);
5183 info.deterministic = false;
5184 return next.study(info);
5185 }
5186 }
5187
5188 /**
5189 * Zero width positive lookahead.
5190 */
5191 static final class Pos extends Node {
5192 Node cond;
5193 Pos(Node cond) {
5194 this.cond = cond;
5195 }
5196 boolean match(Matcher matcher, int i, CharSequence seq) {
5197 int savedTo = matcher.to;
5198 boolean conditionMatched = false;
5199
5200 // Relax transparent region boundaries for lookahead
5201 if (matcher.transparentBounds)
5202 matcher.to = matcher.getTextLength();
5203 try {
5204 conditionMatched = cond.match(matcher, i, seq);
5205 } finally {
5206 // Reinstate region boundaries
5207 matcher.to = savedTo;
5208 }
5209 return conditionMatched && next.match(matcher, i, seq);
5210 }
5211 }
5212
5213 /**
5214 * Zero width negative lookahead.
5215 */
5216 static final class Neg extends Node {
5217 Node cond;
5218 Neg(Node cond) {
5219 this.cond = cond;
5220 }
5221 boolean match(Matcher matcher, int i, CharSequence seq) {
5222 int savedTo = matcher.to;
5223 boolean conditionMatched = false;
5224
5225 // Relax transparent region boundaries for lookahead
5226 if (matcher.transparentBounds)
5227 matcher.to = matcher.getTextLength();
5228 try {
5229 if (i < matcher.to) {
5230 conditionMatched = !cond.match(matcher, i, seq);
5231 } else {
5232 // If a negative lookahead succeeds then more input
5233 // could cause it to fail!
5234 matcher.requireEnd = true;
5235 conditionMatched = !cond.match(matcher, i, seq);
5236 }
5237 } finally {
5238 // Reinstate region boundaries
5239 matcher.to = savedTo;
5240 }
5241 return conditionMatched && next.match(matcher, i, seq);
5242 }
5243 }
5244
5245 /**
5246 * For use with lookbehinds; matches the position where the lookbehind
5247 * was encountered.
5248 */
5249 static Node lookbehindEnd = new Node() {
5250 boolean match(Matcher matcher, int i, CharSequence seq) {
5251 return i == matcher.lookbehindTo;
5252 }
5253 };
5254
5255 /**
5256 * Zero width positive lookbehind.
5257 */
5258 static class Behind extends Node {
5259 Node cond;
5260 int rmax, rmin;
5261 Behind(Node cond, int rmax, int rmin) {
5262 this.cond = cond;
5263 this.rmax = rmax;
5264 this.rmin = rmin;
5265 }
5266
5267 boolean match(Matcher matcher, int i, CharSequence seq) {
5268 int savedFrom = matcher.from;
5269 boolean conditionMatched = false;
5270 int startIndex = (!matcher.transparentBounds) ?
5271 matcher.from : 0;
5272 int from = Math.max(i - rmax, startIndex);
5273 // Set end boundary
5274 int savedLBT = matcher.lookbehindTo;
5275 matcher.lookbehindTo = i;
5276 // Relax transparent region boundaries for lookbehind
5277 if (matcher.transparentBounds)
5278 matcher.from = 0;
5279 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5280 conditionMatched = cond.match(matcher, j, seq);
5281 }
5282 matcher.from = savedFrom;
5283 matcher.lookbehindTo = savedLBT;
5284 return conditionMatched && next.match(matcher, i, seq);
5285 }
5286 }
5287
5288 /**
5289 * Zero width positive lookbehind, including supplementary
5290 * characters or unpaired surrogates.
5291 */
5292 static final class BehindS extends Behind {
5293 BehindS(Node cond, int rmax, int rmin) {
5294 super(cond, rmax, rmin);
5295 }
5296 boolean match(Matcher matcher, int i, CharSequence seq) {
5297 int rmaxChars = countChars(seq, i, -rmax);
5298 int rminChars = countChars(seq, i, -rmin);
5299 int savedFrom = matcher.from;
5300 int startIndex = (!matcher.transparentBounds) ?
5301 matcher.from : 0;
5302 boolean conditionMatched = false;
5303 int from = Math.max(i - rmaxChars, startIndex);
5304 // Set end boundary
5305 int savedLBT = matcher.lookbehindTo;
5306 matcher.lookbehindTo = i;
5307 // Relax transparent region boundaries for lookbehind
5308 if (matcher.transparentBounds)
5309 matcher.from = 0;
5310
5311 for (int j = i - rminChars;
5312 !conditionMatched && j >= from;
5313 j -= j>from ? countChars(seq, j, -1) : 1) {
5314 conditionMatched = cond.match(matcher, j, seq);
5315 }
5316 matcher.from = savedFrom;
5317 matcher.lookbehindTo = savedLBT;
5318 return conditionMatched && next.match(matcher, i, seq);
5319 }
5320 }
5321
5322 /**
5323 * Zero width negative lookbehind.
5324 */
5325 static class NotBehind extends Node {
5326 Node cond;
5327 int rmax, rmin;
5328 NotBehind(Node cond, int rmax, int rmin) {
5329 this.cond = cond;
5330 this.rmax = rmax;
5331 this.rmin = rmin;
5332 }
5333
5334 boolean match(Matcher matcher, int i, CharSequence seq) {
5335 int savedLBT = matcher.lookbehindTo;
5336 int savedFrom = matcher.from;
5337 boolean conditionMatched = false;
5338 int startIndex = (!matcher.transparentBounds) ?
5339 matcher.from : 0;
5340 int from = Math.max(i - rmax, startIndex);
5341 matcher.lookbehindTo = i;
5342 // Relax transparent region boundaries for lookbehind
5343 if (matcher.transparentBounds)
5344 matcher.from = 0;
5345 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5346 conditionMatched = cond.match(matcher, j, seq);
5347 }
5348 // Reinstate region boundaries
5349 matcher.from = savedFrom;
5350 matcher.lookbehindTo = savedLBT;
5351 return !conditionMatched && next.match(matcher, i, seq);
5352 }
5353 }
5354
5355 /**
5356 * Zero width negative lookbehind, including supplementary
5357 * characters or unpaired surrogates.
5358 */
5359 static final class NotBehindS extends NotBehind {
5360 NotBehindS(Node cond, int rmax, int rmin) {
5361 super(cond, rmax, rmin);
5362 }
5363 boolean match(Matcher matcher, int i, CharSequence seq) {
5364 int rmaxChars = countChars(seq, i, -rmax);
5365 int rminChars = countChars(seq, i, -rmin);
5366 int savedFrom = matcher.from;
5367 int savedLBT = matcher.lookbehindTo;
5368 boolean conditionMatched = false;
5369 int startIndex = (!matcher.transparentBounds) ?
5370 matcher.from : 0;
5371 int from = Math.max(i - rmaxChars, startIndex);
5372 matcher.lookbehindTo = i;
5373 // Relax transparent region boundaries for lookbehind
5374 if (matcher.transparentBounds)
5375 matcher.from = 0;
5376 for (int j = i - rminChars;
5377 !conditionMatched && j >= from;
5378 j -= j>from ? countChars(seq, j, -1) : 1) {
5379 conditionMatched = cond.match(matcher, j, seq);
5380 }
5381 //Reinstate region boundaries
5382 matcher.from = savedFrom;
5383 matcher.lookbehindTo = savedLBT;
5384 return !conditionMatched && next.match(matcher, i, seq);
5385 }
5386 }
5387
5388 /**
5389 * Handles word boundaries. Includes a field to allow this one class to
5390 * deal with the different types of word boundaries we can match. The word
5391 * characters include underscores, letters, and digits. Non spacing marks
5392 * can are also part of a word if they have a base character, otherwise
5393 * they are ignored for purposes of finding word boundaries.
5394 */
5395 static final class Bound extends Node {
5396 static int LEFT = 0x1;
5397 static int RIGHT= 0x2;
5398 static int BOTH = 0x3;
5399 static int NONE = 0x4;
5400 int type;
5401 boolean useUWORD;
5402 Bound(int n, boolean useUWORD) {
5403 type = n;
5404 this.useUWORD = useUWORD;
5405 }
5406
5407 boolean isWord(int ch) {
5408 return useUWORD ? CharPredicates.WORD().is(ch)
5409 : (ch == '_' || Character.isLetterOrDigit(ch));
5410 }
5411
5412 int check(Matcher matcher, int i, CharSequence seq) {
5413 int ch;
5414 boolean left = false;
5415 int startIndex = matcher.from;
5416 int endIndex = matcher.to;
5417 if (matcher.transparentBounds) {
5418 startIndex = 0;
5419 endIndex = matcher.getTextLength();
5420 }
5421 if (i > startIndex) {
5422 ch = Character.codePointBefore(seq, i);
5423 left = (isWord(ch) ||
5424 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5425 && hasBaseCharacter(matcher, i-1, seq)));
5426 }
5427 boolean right = false;
5428 if (i < endIndex) {
5429 ch = Character.codePointAt(seq, i);
5430 right = (isWord(ch) ||
5431 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5432 && hasBaseCharacter(matcher, i, seq)));
5433 } else {
5434 // Tried to access char past the end
5435 matcher.hitEnd = true;
5436 // The addition of another char could wreck a boundary
5437 matcher.requireEnd = true;
5438 }
5439 return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE);
5440 }
5441 boolean match(Matcher matcher, int i, CharSequence seq) {
5442 return (check(matcher, i, seq) & type) > 0
5443 && next.match(matcher, i, seq);
5444 }
5445 }
5446
5447 /**
5448 * Non spacing marks only count as word characters in bounds calculations
5449 * if they have a base character.
5450 */
5451 private static boolean hasBaseCharacter(Matcher matcher, int i,
5452 CharSequence seq)
5453 {
5454 int start = (!matcher.transparentBounds) ?
5455 matcher.from : 0;
5456 for (int x=i; x >= start; x--) {
5457 int ch = Character.codePointAt(seq, x);
5458 if (Character.isLetterOrDigit(ch))
5459 return true;
5460 if (Character.getType(ch) == Character.NON_SPACING_MARK)
5461 continue;
5462 return false;
5463 }
5464 return false;
5465 }
5466
5467 /**
5468 * Attempts to match a slice in the input using the Boyer-Moore string
5469 * matching algorithm. The algorithm is based on the idea that the
5470 * pattern can be shifted farther ahead in the search text if it is
5471 * matched right to left.
5472 * <p>
5473 * The pattern is compared to the input one character at a time, from
5474 * the rightmost character in the pattern to the left. If the characters
5475 * all match the pattern has been found. If a character does not match,
5476 * the pattern is shifted right a distance that is the maximum of two
5477 * functions, the bad character shift and the good suffix shift. This
5478 * shift moves the attempted match position through the input more
5479 * quickly than a naive one position at a time check.
5480 * <p>
5481 * The bad character shift is based on the character from the text that
5482 * did not match. If the character does not appear in the pattern, the
5483 * pattern can be shifted completely beyond the bad character. If the
5484 * character does occur in the pattern, the pattern can be shifted to
5485 * line the pattern up with the next occurrence of that character.
5486 * <p>
5487 * The good suffix shift is based on the idea that some subset on the right
5488 * side of the pattern has matched. When a bad character is found, the
5489 * pattern can be shifted right by the pattern length if the subset does
5490 * not occur again in pattern, or by the amount of distance to the
5491 * next occurrence of the subset in the pattern.
5492 *
5493 * Boyer-Moore search methods adapted from code by Amy Yu.
5494 */
5495 static class BnM extends Node {
5496 int[] buffer;
5497 int[] lastOcc;
5498 int[] optoSft;
5499
5500 /**
5501 * Pre calculates arrays needed to generate the bad character
5502 * shift and the good suffix shift. Only the last seven bits
5503 * are used to see if chars match; This keeps the tables small
5504 * and covers the heavily used ASCII range, but occasionally
5505 * results in an aliased match for the bad character shift.
5506 */
5507 static Node optimize(Node node) {
5508 if (!(node instanceof Slice)) {
5509 return node;
5510 }
5511
5512 int[] src = ((Slice) node).buffer;
5513 int patternLength = src.length;
5514 // The BM algorithm requires a bit of overhead;
5515 // If the pattern is short don't use it, since
5516 // a shift larger than the pattern length cannot
5517 // be used anyway.
5518 if (patternLength < 4) {
5519 return node;
5520 }
5521 int i, j, k;
5522 int[] lastOcc = new int[128];
5523 int[] optoSft = new int[patternLength];
5524 // Precalculate part of the bad character shift
5525 // It is a table for where in the pattern each
5526 // lower 7-bit value occurs
5527 for (i = 0; i < patternLength; i++) {
5528 lastOcc[src[i]&0x7F] = i + 1;
5529 }
5530 // Precalculate the good suffix shift
5531 // i is the shift amount being considered
5532 NEXT: for (i = patternLength; i > 0; i--) {
5533 // j is the beginning index of suffix being considered
5534 for (j = patternLength - 1; j >= i; j--) {
5535 // Testing for good suffix
5536 if (src[j] == src[j-i]) {
5537 // src[j..len] is a good suffix
5538 optoSft[j-1] = i;
5539 } else {
5540 // No match. The array has already been
5541 // filled up with correct values before.
5542 continue NEXT;
5543 }
5544 }
5545 // This fills up the remaining of optoSft
5546 // any suffix can not have larger shift amount
5547 // then its sub-suffix. Why???
5548 while (j > 0) {
5549 optoSft[--j] = i;
5550 }
5551 }
5552 // Set the guard value because of unicode compression
5553 optoSft[patternLength-1] = 1;
5554 if (node instanceof SliceS)
5555 return new BnMS(src, lastOcc, optoSft, node.next);
5556 return new BnM(src, lastOcc, optoSft, node.next);
5557 }
5558 BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5559 this.buffer = src;
5560 this.lastOcc = lastOcc;
5561 this.optoSft = optoSft;
5562 this.next = next;
5563 }
5564 boolean match(Matcher matcher, int i, CharSequence seq) {
5565 int[] src = buffer;
5566 int patternLength = src.length;
5567 int last = matcher.to - patternLength;
5568
5569 // Loop over all possible match positions in text
5570 NEXT: while (i <= last) {
5571 // Loop over pattern from right to left
5572 for (int j = patternLength - 1; j >= 0; j--) {
5573 int ch = seq.charAt(i+j);
5574 if (ch != src[j]) {
5575 // Shift search to the right by the maximum of the
5576 // bad character shift and the good suffix shift
5577 i += Math.max(j + 1 - lastOcc[ch&0x7F], optoSft[j]);
5578 continue NEXT;
5579 }
5580 }
5581 // Entire pattern matched starting at i
5582 matcher.first = i;
5583 boolean ret = next.match(matcher, i + patternLength, seq);
5584 if (ret) {
5585 matcher.first = i;
5586 matcher.groups[0] = matcher.first;
5587 matcher.groups[1] = matcher.last;
5588 return true;
5589 }
5590 i++;
5591 }
5592 // BnM is only used as the leading node in the unanchored case,
5593 // and it replaced its Start() which always searches to the end
5594 // if it doesn't find what it's looking for, so hitEnd is true.
5595 matcher.hitEnd = true;
5596 return false;
5597 }
5598 boolean study(TreeInfo info) {
5599 info.minLength += buffer.length;
5600 info.maxValid = false;
5601 return next.study(info);
5602 }
5603 }
5604
5605 /**
5606 * Supplementary support version of BnM(). Unpaired surrogates are
5607 * also handled by this class.
5608 */
5609 static final class BnMS extends BnM {
5610 int lengthInChars;
5611
5612 BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5613 super(src, lastOcc, optoSft, next);
5614 for (int cp : buffer) {
5615 lengthInChars += Character.charCount(cp);
5616 }
5617 }
5618 boolean match(Matcher matcher, int i, CharSequence seq) {
5619 int[] src = buffer;
5620 int patternLength = src.length;
5621 int last = matcher.to - lengthInChars;
5622
5623 // Loop over all possible match positions in text
5624 NEXT: while (i <= last) {
5625 // Loop over pattern from right to left
5626 int ch;
5627 for (int j = countChars(seq, i, patternLength), x = patternLength - 1;
5628 j > 0; j -= Character.charCount(ch), x--) {
5629 ch = Character.codePointBefore(seq, i+j);
5630 if (ch != src[x]) {
5631 // Shift search to the right by the maximum of the
5632 // bad character shift and the good suffix shift
5633 int n = Math.max(x + 1 - lastOcc[ch&0x7F], optoSft[x]);
5634 i += countChars(seq, i, n);
5635 continue NEXT;
5636 }
5637 }
5638 // Entire pattern matched starting at i
5639 matcher.first = i;
5640 boolean ret = next.match(matcher, i + lengthInChars, seq);
5641 if (ret) {
5642 matcher.first = i;
5643 matcher.groups[0] = matcher.first;
5644 matcher.groups[1] = matcher.last;
5645 return true;
5646 }
5647 i += countChars(seq, i, 1);
5648 }
5649 matcher.hitEnd = true;
5650 return false;
5651 }
5652 }
5653
5654 @FunctionalInterface
5655 static interface CharPredicate {
5656 boolean is(int ch);
5657
5658 default CharPredicate and(CharPredicate p) {
5659 return ch -> is(ch) && p.is(ch);
5660 }
5661 default CharPredicate union(CharPredicate p) {
5662 return ch -> is(ch) || p.is(ch);
5663 }
5664 default CharPredicate union(CharPredicate p1,
5665 CharPredicate p2 ) {
5666 return ch -> is(ch) || p1.is(ch) || p2.is(ch);
5667 }
5668 default CharPredicate negate() {
5669 return ch -> !is(ch);
5670 }
5671 }
5672
5673 static interface BmpCharPredicate extends CharPredicate {
5674
5675 default CharPredicate and(CharPredicate p) {
5676 if(p instanceof BmpCharPredicate)
5677 return (BmpCharPredicate)(ch -> is(ch) && p.is(ch));
5678 return ch -> is(ch) && p.is(ch);
5679 }
5680 default CharPredicate union(CharPredicate p) {
5681 if (p instanceof BmpCharPredicate)
5682 return (BmpCharPredicate)(ch -> is(ch) || p.is(ch));
5683 return ch -> is(ch) || p.is(ch);
5684 }
5685 static CharPredicate union(CharPredicate... predicates) {
5686 CharPredicate cp = ch -> {
5687 for (CharPredicate p : predicates) {
5688 if (!p.is(ch))
5689 return false;
5690 }
5691 return true;
5692 };
5693 for (CharPredicate p : predicates) {
5694 if (! (p instanceof BmpCharPredicate))
5695 return cp;
5696 }
5697 return (BmpCharPredicate)cp;
5698 }
5699 }
5700
5701 /**
5702 * matches a Perl vertical whitespace
5703 */
5704 static BmpCharPredicate VertWS() {
5705 return cp -> (cp >= 0x0A && cp <= 0x0D) ||
5706 cp == 0x85 || cp == 0x2028 || cp == 0x2029;
5707 }
5708
5709 /**
5710 * matches a Perl horizontal whitespace
5711 */
5712 static BmpCharPredicate HorizWS() {
5713 return cp ->
5714 cp == 0x09 || cp == 0x20 || cp == 0xa0 || cp == 0x1680 ||
5715 cp == 0x180e || cp >= 0x2000 && cp <= 0x200a || cp == 0x202f ||
5716 cp == 0x205f || cp == 0x3000;
5717 }
5718
5719 /**
5720 * for the Unicode category ALL and the dot metacharacter when
5721 * in dotall mode.
5722 */
5723 static CharPredicate ALL() {
5724 return ch -> true;
5725 }
5726
5727 /**
5728 * for the dot metacharacter when dotall is not enabled.
5729 */
5730 static CharPredicate DOT() {
5731 return ch ->
5732 (ch != '\n' && ch != '\r'
5733 && (ch|1) != '\u2029'
5734 && ch != '\u0085');
5735 }
5736
5737 /**
5738 * the dot metacharacter when dotall is not enabled but UNIX_LINES is enabled.
5739 */
5740 static CharPredicate UNIXDOT() {
5741 return ch -> ch != '\n';
5742 }
5743
5744 /**
5745 * Indicate that matches a Supplementary Unicode character
5746 */
5747 static CharPredicate SingleS(int c) {
5748 return ch -> ch == c;
5749 }
5750
5751 /**
5752 * A bmp/optimized predicate of single
5753 */
5754 static BmpCharPredicate Single(int c) {
5755 return ch -> ch == c;
5756 }
5757
5758 /**
5759 * Case insensitive matches a given BMP character
5760 */
5761 static BmpCharPredicate SingleI(int lower, int upper) {
5762 return ch -> ch == lower || ch == upper;
5763 }
5764
5765 /**
5766 * Unicode case insensitive matches a given Unicode character
5767 */
5768 static CharPredicate SingleU(int lower) {
5769 return ch -> lower == ch ||
5770 lower == Character.toLowerCase(Character.toUpperCase(ch));
5771 }
5772
5773 private static boolean inRange(int lower, int ch, int upper) {
5774 return lower <= ch && ch <= upper;
5775 }
5776
5777 /**
5778 * Charactrs within a explicit value range
5779 */
5780 static CharPredicate Range(int lower, int upper) {
5781 if (upper < Character.MIN_HIGH_SURROGATE ||
5782 lower > Character.MAX_HIGH_SURROGATE &&
5783 upper < Character.MIN_SUPPLEMENTARY_CODE_POINT)
5784 return (BmpCharPredicate)(ch -> inRange(lower, ch, upper));
5785 return ch -> inRange(lower, ch, upper);
5786 }
5787
5788 /**
5789 * Charactrs within a explicit value range in a case insensitive manner.
5790 */
5791 static CharPredicate CIRange(int lower, int upper) {
5792 return ch -> inRange(lower, ch, upper) ||
5793 ASCII.isAscii(ch) &&
5794 (inRange(lower, ASCII.toUpper(ch), upper) ||
5795 inRange(lower, ASCII.toLower(ch), upper));
5796 }
5797
5798 static CharPredicate CIRangeU(int lower, int upper) {
5799 return ch -> {
5800 if (inRange(lower, ch, upper))
5801 return true;
5802 int up = Character.toUpperCase(ch);
5803 return inRange(lower, up, upper) ||
5804 inRange(lower, Character.toLowerCase(up), upper);
5805 };
5806 }
5807
5808 /**
5809 * This must be the very first initializer.
5810 */
5811 static final Node accept = new Node();
5812
5813 static final Node lastAccept = new LastNode();
5814
5815 /**
5816 * Creates a predicate which can be used to match a string.
5817 *
5818 * @return The predicate which can be used for matching on a string
5819 * @since 1.8
5820 */
5821 public Predicate<String> asPredicate() {
5822 return s -> matcher(s).find();
5823 }
5824
5825 /**
5826 * Creates a stream from the given input sequence around matches of this
5827 * pattern.
5828 *
5829 * <p> The stream returned by this method contains each substring of the
5830 * input sequence that is terminated by another subsequence that matches
5831 * this pattern or is terminated by the end of the input sequence. The
5832 * substrings in the stream are in the order in which they occur in the
5833 * input. Trailing empty strings will be discarded and not encountered in
5834 * the stream.
5835 *
5836 * <p> If this pattern does not match any subsequence of the input then
5837 * the resulting stream has just one element, namely the input sequence in
5838 * string form.
5839 *
5840 * <p> When there is a positive-width match at the beginning of the input
5841 * sequence then an empty leading substring is included at the beginning
5842 * of the stream. A zero-width match at the beginning however never produces
5843 * such empty leading substring.
5844 *
5845 * <p> If the input sequence is mutable, it must remain constant during the
5846 * execution of the terminal stream operation. Otherwise, the result of the
5847 * terminal stream operation is undefined.
5848 *
5849 * @param input
5850 * The character sequence to be split
5851 *
5852 * @return The stream of strings computed by splitting the input
5853 * around matches of this pattern
5854 * @see #split(CharSequence)
5855 * @since 1.8
5856 */
5857 public Stream<String> splitAsStream(final CharSequence input) {
5858 class MatcherIterator implements Iterator<String> {
5859 private Matcher matcher;
5860 // The start position of the next sub-sequence of input
5861 // when current == input.length there are no more elements
5862 private int current;
5863 // null if the next element, if any, needs to obtained
5864 private String nextElement;
5865 // > 0 if there are N next empty elements
5866 private int emptyElementCount;
5867
5868 public String next() {
5869 if (!hasNext())
5870 throw new NoSuchElementException();
5871
5872 if (emptyElementCount == 0) {
5873 String n = nextElement;
5874 nextElement = null;
5875 return n;
5876 } else {
5877 emptyElementCount--;
5878 return "";
5879 }
5880 }
5881
5882 public boolean hasNext() {
5883 if (matcher == null) {
5884 matcher = matcher(input);
5885 // If the input is an empty string then the result can only be a
5886 // stream of the input. Induce that by setting the empty
5887 // element count to 1
5888 emptyElementCount = input.length() == 0 ? 1 : 0;
5889 }
5890 if (nextElement != null || emptyElementCount > 0)
5891 return true;
5892
5893 if (current == input.length())
5894 return false;
5895
5896 // Consume the next matching element
5897 // Count sequence of matching empty elements
5898 while (matcher.find()) {
5899 nextElement = input.subSequence(current, matcher.start()).toString();
5900 current = matcher.end();
5901 if (!nextElement.isEmpty()) {
5902 return true;
5903 } else if (current > 0) { // no empty leading substring for zero-width
5904 // match at the beginning of the input
5905 emptyElementCount++;
5906 }
5907 }
5908
5909 // Consume last matching element
5910 nextElement = input.subSequence(current, input.length()).toString();
5911 current = input.length();
5912 if (!nextElement.isEmpty()) {
5913 return true;
5914 } else {
5915 // Ignore a terminal sequence of matching empty elements
5916 emptyElementCount = 0;
5917 nextElement = null;
5918 return false;
5919 }
5920 }
5921 }
5922 return StreamSupport.stream(Spliterators.spliteratorUnknownSize(
5923 new MatcherIterator(), Spliterator.ORDERED | Spliterator.NONNULL), false);
5924 }
5925 }