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