1 /*
2 * Copyright (c) 1999, 2019, 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 * <h2><a id="sum">Summary of regular-expression constructs</a></h2>
81 *
82 * <table class="borderless">
83 * <caption style="display:none">Regular expression constructs, and what they match</caption>
84 * <thead style="text-align:left">
85 * <tr>
86 * <th id="construct">Construct</th>
87 * <th id="matches">Matches</th>
88 * </tr>
89 * </thead>
90 * <tbody style="text-align:left">
91 *
92 * <tr><th colspan="2" style="padding-top:20px" id="characters">Characters</th></tr>
93 *
94 * <tr><th style="vertical-align:top; font-weight: normal" id="x"><i>x</i></th>
95 * <td headers="matches characters x">The character <i>x</i></td></tr>
96 * <tr><th style="vertical-align:top; font-weight: normal" id="backslash">{@code \\}</th>
97 * <td headers="matches characters backslash">The backslash character</td></tr>
98 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_n">{@code \0}<i>n</i></th>
99 * <td headers="matches characters octal_n">The character with octal value {@code 0}<i>n</i>
100 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
101 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nn">{@code \0}<i>nn</i></th>
102 * <td headers="matches characters octal_nn">The character with octal value {@code 0}<i>nn</i>
103 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
104 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nnn">{@code \0}<i>mnn</i></th>
105 * <td headers="matches characters octal_nnn">The character with octal value {@code 0}<i>mnn</i>
106 * (0 {@code <=} <i>m</i> {@code <=} 3,
107 * 0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
108 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hh">{@code \x}<i>hh</i></th>
109 * <td headers="matches characters hex_hh">The character with hexadecimal value {@code 0x}<i>hh</i></td></tr>
110 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hhhh"><code>\u</code><i>hhhh</i></th>
111 * <td headers="matches characters hex_hhhh">The character with hexadecimal value {@code 0x}<i>hhhh</i></td></tr>
112 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_h_h"><code>\x</code><i>{h...h}</i></th>
113 * <td headers="matches characters hex_h_h">The character with hexadecimal value {@code 0x}<i>h...h</i>
114 * ({@link java.lang.Character#MIN_CODE_POINT Character.MIN_CODE_POINT}
115 * <= {@code 0x}<i>h...h</i> <=
116 * {@link java.lang.Character#MAX_CODE_POINT Character.MAX_CODE_POINT})</td></tr>
117 * <tr><th style="vertical-align:top; font-weight: normal" id="unicode_name"><code>\N{</code><i>name</i><code>}</code></th>
118 * <td headers="matches characters unicode_name">The character with Unicode character name <i>'name'</i></td></tr>
119 * <tr><th style="vertical-align:top; font-weight:normal" id="tab">{@code \t}</th>
120 * <td headers="matches characters tab">The tab character (<code>'\u0009'</code>)</td></tr>
121 * <tr><th style="vertical-align:top; font-weight:normal" id="newline">{@code \n}</th>
122 * <td headers="matches characters newline">The newline (line feed) character (<code>'\u000A'</code>)</td></tr>
123 * <tr><th style="vertical-align:top; font-weight:normal" id="return">{@code \r}</th>
124 * <td headers="matches characters return">The carriage-return character (<code>'\u000D'</code>)</td></tr>
125 * <tr><th style="vertical-align:top; font-weight:normal" id="form_feed">{@code \f}</th>
126 * <td headers="matches characters form_feed">The form-feed character (<code>'\u000C'</code>)</td></tr>
127 * <tr><th style="vertical-align:top; font-weight:normal" id="bell">{@code \a}</th>
128 * <td headers="matches characters bell">The alert (bell) character (<code>'\u0007'</code>)</td></tr>
129 * <tr><th style="vertical-align:top; font-weight:normal" id="escape">{@code \e}</th>
130 * <td headers="matches characters escape">The escape character (<code>'\u001B'</code>)</td></tr>
131 * <tr><th style="vertical-align:top; font-weight:normal" id="ctrl_x">{@code \c}<i>x</i></th>
132 * <td headers="matches characters ctrl_x">The control character corresponding to <i>x</i></td></tr>
133 *
134 * <tr><th colspan="2" style="padding-top:20px" id="classes">Character classes</th></tr>
135 *
136 * <tr><th style="vertical-align:top; font-weight:normal" id="simple">{@code [abc]}</th>
137 * <td headers="matches classes simple">{@code a}, {@code b}, or {@code c} (simple class)</td></tr>
138 * <tr><th style="vertical-align:top; font-weight:normal" id="negation">{@code [^abc]}</th>
139 * <td headers="matches classes negation">Any character except {@code a}, {@code b}, or {@code c} (negation)</td></tr>
140 * <tr><th style="vertical-align:top; font-weight:normal" id="range">{@code [a-zA-Z]}</th>
141 * <td headers="matches classes range">{@code a} through {@code z}
142 * or {@code A} through {@code Z}, inclusive (range)</td></tr>
143 * <tr><th style="vertical-align:top; font-weight:normal" id="union">{@code [a-d[m-p]]}</th>
144 * <td headers="matches classes union">{@code a} through {@code d},
145 * or {@code m} through {@code p}: {@code [a-dm-p]} (union)</td></tr>
146 * <tr><th style="vertical-align:top; font-weight:normal" id="intersection">{@code [a-z&&[def]]}</th>
147 * <td headers="matches classes intersection">{@code d}, {@code e}, or {@code f} (intersection)</tr>
148 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction1">{@code [a-z&&[^bc]]}</th>
149 * <td headers="matches classes subtraction1">{@code a} through {@code z},
150 * except for {@code b} and {@code c}: {@code [ad-z]} (subtraction)</td></tr>
151 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction2">{@code [a-z&&[^m-p]]}</th>
152 * <td headers="matches classes subtraction2">{@code a} through {@code z},
153 * and not {@code m} through {@code p}: {@code [a-lq-z]}(subtraction)</td></tr>
154 *
155 * <tr><th colspan="2" style="padding-top:20px" id="predef">Predefined character classes</th></tr>
156 *
157 * <tr><th style="vertical-align:top; font-weight:normal" id="any">{@code .}</th>
158 * <td headers="matches predef any">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
159 * <tr><th style="vertical-align:top; font-weight:normal" id="digit">{@code \d}</th>
160 * <td headers="matches predef digit">A digit: {@code [0-9]}</td></tr>
161 * <tr><th style="vertical-align:top; font-weight:normal" id="non_digit">{@code \D}</th>
162 * <td headers="matches predef non_digit">A non-digit: {@code [^0-9]}</td></tr>
163 * <tr><th style="vertical-align:top; font-weight:normal" id="horiz_white">{@code \h}</th>
164 * <td headers="matches predef horiz_white">A horizontal whitespace character:
165 * <code>[ \t\xA0\u1680\u180e\u2000-\u200a\u202f\u205f\u3000]</code></td></tr>
166 * <tr><th style="vertical-align:top; font-weight:normal" id="non_horiz_white">{@code \H}</th>
167 * <td headers="matches predef non_horiz_white">A non-horizontal whitespace character: {@code [^\h]}</td></tr>
168 * <tr><th style="vertical-align:top; font-weight:normal" id="white">{@code \s}</th>
169 * <td headers="matches predef white">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
170 * <tr><th style="vertical-align:top; font-weight:normal" id="non_white">{@code \S}</th>
171 * <td headers="matches predef non_white">A non-whitespace character: {@code [^\s]}</td></tr>
172 * <tr><th style="vertical-align:top; font-weight:normal" id="vert_white">{@code \v}</th>
173 * <td headers="matches predef vert_white">A vertical whitespace character: <code>[\n\x0B\f\r\x85\u2028\u2029]</code>
174 * </td></tr>
175 * <tr><th style="vertical-align:top; font-weight:normal" id="non_vert_white">{@code \V}</th>
176 * <td headers="matches predef non_vert_white">A non-vertical whitespace character: {@code [^\v]}</td></tr>
177 * <tr><th style="vertical-align:top; font-weight:normal" id="word">{@code \w}</th>
178 * <td headers="matches predef word">A word character: {@code [a-zA-Z_0-9]}</td></tr>
179 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word">{@code \W}</th>
180 * <td headers="matches predef non_word">A non-word character: {@code [^\w]}</td></tr>
181 *
182 * <tr><th colspan="2" style="padding-top:20px" id="posix"><b>POSIX character classes (US-ASCII only)</b></th></tr>
183 *
184 * <tr><th style="vertical-align:top; font-weight:normal" id="Lower">{@code \p{Lower}}</th>
185 * <td headers="matches posix Lower">A lower-case alphabetic character: {@code [a-z]}</td></tr>
186 * <tr><th style="vertical-align:top; font-weight:normal" id="Upper">{@code \p{Upper}}</th>
187 * <td headers="matches posix Upper">An upper-case alphabetic character:{@code [A-Z]}</td></tr>
188 * <tr><th style="vertical-align:top; font-weight:normal" id="ASCII">{@code \p{ASCII}}</th>
189 * <td headers="matches posix ASCII">All ASCII:{@code [\x00-\x7F]}</td></tr>
190 * <tr><th style="vertical-align:top; font-weight:normal" id="Alpha">{@code \p{Alpha}}</th>
191 * <td headers="matches posix Alpha">An alphabetic character:{@code [\p{Lower}\p{Upper}]}</td></tr>
192 * <tr><th style="vertical-align:top; font-weight:normal" id="Digit">{@code \p{Digit}}</th>
193 * <td headers="matches posix Digit">A decimal digit: {@code [0-9]}</td></tr>
194 * <tr><th style="vertical-align:top; font-weight:normal" id="Alnum">{@code \p{Alnum}}</th>
195 * <td headers="matches posix Alnum">An alphanumeric character:{@code [\p{Alpha}\p{Digit}]}</td></tr>
196 * <tr><th style="vertical-align:top; font-weight:normal" id="Punct">{@code \p{Punct}}</th>
197 * <td headers="matches posix Punct">Punctuation: One of {@code !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~}</td></tr>
198 * <!-- {@code [\!"#\$%&'\(\)\*\+,\-\./:;\<=\>\?@\[\\\]\^_`\{\|\}~]}
199 * {@code [\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]} -->
200 * <tr><th style="vertical-align:top; font-weight:normal" id="Graph">{@code \p{Graph}}</th>
201 * <td headers="matches posix Graph">A visible character: {@code [\p{Alnum}\p{Punct}]}</td></tr>
202 * <tr><th style="vertical-align:top; font-weight:normal" id="Print">{@code \p{Print}}</th>
203 * <td headers="matches posix Print">A printable character: {@code [\p{Graph}\x20]}</td></tr>
204 * <tr><th style="vertical-align:top; font-weight:normal" id="Blank">{@code \p{Blank}}</th>
205 * <td headers="matches posix Blank">A space or a tab: {@code [ \t]}</td></tr>
206 * <tr><th style="vertical-align:top; font-weight:normal" id="Cntrl">{@code \p{Cntrl}}</th>
207 * <td headers="matches posix Cntrl">A control character: {@code [\x00-\x1F\x7F]}</td></tr>
208 * <tr><th style="vertical-align:top; font-weight:normal" id="XDigit">{@code \p{XDigit}}</th>
209 * <td headers="matches posix XDigit">A hexadecimal digit: {@code [0-9a-fA-F]}</td></tr>
210 * <tr><th style="vertical-align:top; font-weight:normal" id="Space">{@code \p{Space}}</th>
211 * <td headers="matches posix Space">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
212 *
213 * <tr><th colspan="2" style="padding-top:20px" id="java">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr>
214 *
215 * <tr><th style="vertical-align:top; font-weight:normal" id="javaLowerCase">{@code \p{javaLowerCase}}</th>
216 * <td headers="matches java javaLowerCase">Equivalent to java.lang.Character.isLowerCase()</td></tr>
217 * <tr><th style="vertical-align:top; font-weight:normal" id="javaUpperCase">{@code \p{javaUpperCase}}</th>
218 * <td headers="matches java javaUpperCase">Equivalent to java.lang.Character.isUpperCase()</td></tr>
219 * <tr><th style="vertical-align:top; font-weight:normal" id="javaWhitespace">{@code \p{javaWhitespace}}</th>
220 * <td headers="matches java javaWhitespace">Equivalent to java.lang.Character.isWhitespace()</td></tr>
221 * <tr><th style="vertical-align:top; font-weight:normal" id="javaMirrored">{@code \p{javaMirrored}}</th>
222 * <td headers="matches java javaMirrored">Equivalent to java.lang.Character.isMirrored()</td></tr>
223 *
224 * <tr><th colspan="2" style="padding-top:20px" id="unicode">Classes for Unicode scripts, blocks, categories and binary properties</th></tr>
225 *
226 * <tr><th style="vertical-align:top; font-weight:normal" id="IsLatin">{@code \p{IsLatin}}</th>
227 * <td headers="matches unicode IsLatin">A Latin script character (<a href="#usc">script</a>)</td></tr>
228 * <tr><th style="vertical-align:top; font-weight:normal" id="InGreek">{@code \p{InGreek}}</th>
229 * <td headers="matches unicode InGreek">A character in the Greek block (<a href="#ubc">block</a>)</td></tr>
230 * <tr><th style="vertical-align:top; font-weight:normal" id="Lu">{@code \p{Lu}}</th>
231 * <td headers="matches unicode Lu">An uppercase letter (<a href="#ucc">category</a>)</td></tr>
232 * <tr><th style="vertical-align:top; font-weight:normal" id="IsAlphabetic">{@code \p{IsAlphabetic}}</th>
233 * <td headers="matches unicode IsAlphabetic">An alphabetic character (<a href="#ubpc">binary property</a>)</td></tr>
234 * <tr><th style="vertical-align:top; font-weight:normal" id="Sc">{@code \p{Sc}}</th>
235 * <td headers="matches unicode Sc">A currency symbol</td></tr>
236 * <tr><th style="vertical-align:top; font-weight:normal" id="not_InGreek">{@code \P{InGreek}}</th>
237 * <td headers="matches unicode not_InGreek">Any character except one in the Greek block (negation)</td></tr>
238 * <tr><th style="vertical-align:top; font-weight:normal" id="not_uppercase">{@code [\p{L}&&[^\p{Lu}]]}</th>
239 * <td headers="matches unicode not_uppercase">Any letter except an uppercase letter (subtraction)</td></tr>
240 *
241 * <tr><th colspan="2" style="padding-top:20px" id="bounds">Boundary matchers</th></tr>
242 *
243 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_line">{@code ^}</th>
244 * <td headers="matches bounds begin_line">The beginning of a line</td></tr>
245 * <tr><th style="vertical-align:top; font-weight:normal" id="end_line">{@code $}</th>
246 * <td headers="matches bounds end_line">The end of a line</td></tr>
247 * <tr><th style="vertical-align:top; font-weight:normal" id="word_boundary">{@code \b}</th>
248 * <td headers="matches bounds word_boundary">A word boundary</td></tr>
249 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_cluster_boundary">{@code \b{g}}</th>
250 * <td headers="matches bounds grapheme_cluster_boundary">A Unicode extended grapheme cluster boundary</td></tr>
251 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word_boundary">{@code \B}</th>
252 * <td headers="matches bounds non_word_boundary">A non-word boundary</td></tr>
253 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_input">{@code \A}</th>
254 * <td headers="matches bounds begin_input">The beginning of the input</td></tr>
255 * <tr><th style="vertical-align:top; font-weight:normal" id="end_prev_match">{@code \G}</th>
256 * <td headers="matches bounds end_prev_match">The end of the previous match</td></tr>
257 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input_except_term">{@code \Z}</th>
258 * <td headers="matches bounds end_input_except_term">The end of the input but for the final
259 * <a href="#lt">terminator</a>, if any</td></tr>
260 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input">{@code \z}</th>
261 * <td headers="matches bounds end_input">The end of the input</td></tr>
262 *
263 * <tr><th colspan="2" style="padding-top:20px" id="linebreak">Linebreak matcher</th></tr>
264 *
265 * <tr><th style="vertical-align:top; font-weight:normal" id="any_unicode_linebreak">{@code \R}</th>
266 * <td headers="matches linebreak any_unicode_linebreak">Any Unicode linebreak sequence, is equivalent to
267 * <code>\u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029]
268 * </code></td></tr>
269 *
270 * <tr><th colspan="2" style="padding-top:20px" id="grapheme">Unicode Extended Grapheme matcher</th></tr>
271 *
272 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_any">{@code \X}</th>
273 * <td headers="matches grapheme grapheme_any">Any Unicode extended grapheme cluster</td></tr>
274 *
275 * <tr><th colspan="2" style="padding-top:20px" id="greedy">Greedy quantifiers</th></tr>
276 *
277 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_once_or_not"><i>X</i>{@code ?}</th>
278 * <td headers="matches greedy greedy_once_or_not"><i>X</i>, once or not at all</td></tr>
279 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_zero_or_more"><i>X</i>{@code *}</th>
280 * <td headers="matches greedy greedy_zero_or_more"><i>X</i>, zero or more times</td></tr>
281 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_one_or_more"><i>X</i>{@code +}</th>
282 * <td headers="matches greedy greedy_one_or_more"><i>X</i>, one or more times</td></tr>
283 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_exactly"><i>X</i><code>{</code><i>n</i><code>}</code></th>
284 * <td headers="matches greedy greedy_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
285 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least"><i>X</i><code>{</code><i>n</i>{@code ,}}</th>
286 * <td headers="matches greedy greedy_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
287 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}</code></th>
288 * <td headers="matches greedy greedy_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
289 *
290 * <tr><th colspan="2" style="padding-top:20px" id="reluc">Reluctant quantifiers</th></tr>
291 *
292 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_once_or_not"><i>X</i>{@code ??}</th>
293 * <td headers="matches reluc reluc_once_or_not"><i>X</i>, once or not at all</td></tr>
294 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_zero_or_more"><i>X</i>{@code *?}</th>
295 * <td headers="matches reluc reluc_zero_or_more"><i>X</i>, zero or more times</td></tr>
296 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_one_or_more"><i>X</i>{@code +?}</th>
297 * <td headers="matches reluc reluc_one_or_more"><i>X</i>, one or more times</td></tr>
298 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_exactly"><i>X</i><code>{</code><i>n</i><code>}?</code></th>
299 * <td headers="matches reluc reluc_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
300 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least"><i>X</i><code>{</code><i>n</i><code>,}?</code></th>
301 * <td headers="matches reluc reluc_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
302 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}?</code></th>
303 * <td headers="matches reluc reluc_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
304 *
305 * <tr><th colspan="2" style="padding-top:20px" id="poss">Possessive quantifiers</th></tr>
306 *
307 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_once_or_not"><i>X</i>{@code ?+}</th>
308 * <td headers="matches poss poss_once_or_not"><i>X</i>, once or not at all</td></tr>
309 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_zero_or_more"><i>X</i>{@code *+}</th>
310 * <td headers="matches poss poss_zero_or_more"><i>X</i>, zero or more times</td></tr>
311 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_one_or_more"><i>X</i>{@code ++}</th>
312 * <td headers="matches poss poss_one_or_more"><i>X</i>, one or more times</td></tr>
313 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_exactly"><i>X</i><code>{</code><i>n</i><code>}+</code></th>
314 * <td headers="matches poss poss_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
315 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least"><i>X</i><code>{</code><i>n</i><code>,}+</code></th>
316 * <td headers="matches poss poss_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
317 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}+</code></th>
318 * <td headers="matches poss poss_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
319 *
320 * <tr><th colspan="2" style="padding-top:20px" id="logical">Logical operators</th></tr>
321 *
322 * <tr><th style="vertical-align:top; font-weight:normal" id="concat"><i>XY</i></th>
323 * <td headers="matches logical concat"><i>X</i> followed by <i>Y</i></td></tr>
324 * <tr><th style="vertical-align:top; font-weight:normal" id="alternate"><i>X</i>{@code |}<i>Y</i></th>
325 * <td headers="matches logical alternate">Either <i>X</i> or <i>Y</i></td></tr>
326 * <tr><th style="vertical-align:top; font-weight:normal" id="group">{@code (}<i>X</i>{@code )}</th>
327 * <td headers="matches logical group">X, as a <a href="#cg">capturing group</a></td></tr>
328 *
329 * <tr><th colspan="2" style="padding-top:20px" id="backref">Back references</th></tr>
330 *
331 * <tr><th style="vertical-align:top; font-weight:normal" id="back_nth">{@code \}<i>n</i></th>
332 * <td headers="matches backref back_nth">Whatever the <i>n</i><sup>th</sup>
333 * <a href="#cg">capturing group</a> matched</td></tr>
334 * <tr><th style="vertical-align:top; font-weight:normal" id="back_named">{@code \}<i>k</i><<i>name</i>></th>
335 * <td headers="matches backref back_named">Whatever the
336 * <a href="#groupname">named-capturing group</a> "name" matched</td></tr>
337 *
338 * <tr><th colspan="2" style="padding-top:20px" id="quote">Quotation</th></tr>
339 *
340 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_follow">{@code \}</th>
341 * <td headers="matches quote quote_follow">Nothing, but quotes the following character</td></tr>
342 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_begin">{@code \Q}</th>
343 * <td headers="matches quote quote_begin">Nothing, but quotes all characters until {@code \E}</td></tr>
344 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_end">{@code \E}</th>
345 * <td headers="matches quote quote_end">Nothing, but ends quoting started by {@code \Q}</td></tr>
346 * <!-- Metachars: !$()*+.<>?[\]^{|} -->
347 *
348 * <tr><th colspan="2" style="padding-top:20px" id="special">Special constructs (named-capturing and non-capturing)</th></tr>
349 *
350 * <tr><th style="vertical-align:top; font-weight:normal" id="named_group"><code>(?<<a href="#groupname">name</a>></code><i>X</i>{@code )}</th>
351 * <td headers="matches special named_group"><i>X</i>, as a named-capturing group</td></tr>
352 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group">{@code (?:}<i>X</i>{@code )}</th>
353 * <td headers="matches special non_capture_group"><i>X</i>, as a non-capturing group</td></tr>
354 * <tr><th style="vertical-align:top; font-weight:normal" id="flags"><code>(?idmsuxU-idmsuxU) </code></th>
355 * <td headers="matches special flags">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a>
356 * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a>
357 * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> <a href="#UNICODE_CHARACTER_CLASS">U</a>
358 * on - off</td></tr>
359 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group_flags"><code>(?idmsux-idmsux:</code><i>X</i>{@code )} </th>
360 * <td headers="matches special non_capture_group_flags"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the
361 * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a>
362 * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a >
363 * <a href="#COMMENTS">x</a> on - off</td></tr>
364 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookahead">{@code (?=}<i>X</i>{@code )}</th>
365 * <td headers="matches special pos_lookahead"><i>X</i>, via zero-width positive lookahead</td></tr>
366 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookahead">{@code (?!}<i>X</i>{@code )}</th>
367 * <td headers="matches special neg_lookahead"><i>X</i>, via zero-width negative lookahead</td></tr>
368 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookbehind">{@code (?<=}<i>X</i>{@code )}</th>
369 * <td headers="matches special pos_lookbehind"><i>X</i>, via zero-width positive lookbehind</td></tr>
370 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookbehind">{@code (?<!}<i>X</i>{@code )}</th>
371 * <td headers="matches special neg_lookbehind"><i>X</i>, via zero-width negative lookbehind</td></tr>
372 * <tr><th style="vertical-align:top; font-weight:normal" id="indep_non_capture_group">{@code (?>}<i>X</i>{@code )}</th>
373 * <td headers="matches special indep_non_capture_group"><i>X</i>, as an independent, non-capturing group</td></tr>
374 *
375 * </tbody>
376 * </table>
377 *
378 * <hr>
379 *
380 *
381 * <h2><a id="bs">Backslashes, escapes, and quoting</a></h2>
382 *
383 * <p> The backslash character ({@code '\'}) serves to introduce escaped
384 * constructs, as defined in the table above, as well as to quote characters
385 * that otherwise would be interpreted as unescaped constructs. Thus the
386 * expression {@code \\} matches a single backslash and <code>\{</code> matches a
387 * left brace.
388 *
389 * <p> It is an error to use a backslash prior to any alphabetic character that
390 * does not denote an escaped construct; these are reserved for future
391 * extensions to the regular-expression language. A backslash may be used
392 * prior to a non-alphabetic character regardless of whether that character is
393 * part of an unescaped construct.
394 *
395 * <p> Backslashes within string literals in Java source code are interpreted
396 * as required by
397 * <cite>The Java™ Language Specification</cite>
398 * as either Unicode escapes (section 3.3) or other character escapes (section 3.10.6)
399 * It is therefore necessary to double backslashes in string
400 * literals that represent regular expressions to protect them from
401 * interpretation by the Java bytecode compiler. The string literal
402 * <code>"\b"</code>, for example, matches a single backspace character when
403 * interpreted as a regular expression, while {@code "\\b"} matches a
404 * word boundary. The string literal {@code "\(hello\)"} is illegal
405 * and leads to a compile-time error; in order to match the string
406 * {@code (hello)} the string literal {@code "\\(hello\\)"}
407 * must be used.
408 *
409 * <h2><a id="cc">Character Classes</a></h2>
410 *
411 * <p> Character classes may appear within other character classes, and
412 * may be composed by the union operator (implicit) and the intersection
413 * operator ({@code &&}).
414 * The union operator denotes a class that contains every character that is
415 * in at least one of its operand classes. The intersection operator
416 * denotes a class that contains every character that is in both of its
417 * operand classes.
418 *
419 * <p> The precedence of character-class operators is as follows, from
420 * highest to lowest:
421 *
422 * <table class="striped" style="margin-left: 2em;">
423 * <caption style="display:none">Precedence of character class operators.</caption>
424 * <thead>
425 * <tr><th scope="col">Precedence<th scope="col">Name<th scope="col">Example
426 * </thead>
427 * <tbody>
428 * <tr><th scope="row">1</th>
429 * <td>Literal escape </td>
430 * <td>{@code \x}</td></tr>
431 * <tr><th scope="row">2</th>
432 * <td>Grouping</td>
433 * <td>{@code [...]}</td></tr>
434 * <tr><th scope="row">3</th>
435 * <td>Range</td>
436 * <td>{@code a-z}</td></tr>
437 * <tr><th scope="row">4</th>
438 * <td>Union</td>
439 * <td>{@code [a-e][i-u]}</td></tr>
440 * <tr><th scope="row">5</th>
441 * <td>Intersection</td>
442 * <td>{@code [a-z&&[aeiou]]}</td></tr>
443 * </tbody>
444 * </table>
445 *
446 * <p> Note that a different set of metacharacters are in effect inside
447 * a character class than outside a character class. For instance, the
448 * regular expression {@code .} loses its special meaning inside a
449 * character class, while the expression {@code -} becomes a range
450 * forming metacharacter.
451 *
452 * <h2><a id="lt">Line terminators</a></h2>
453 *
454 * <p> A <i>line terminator</i> is a one- or two-character sequence that marks
455 * the end of a line of the input character sequence. The following are
456 * recognized as line terminators:
457 *
458 * <ul>
459 *
460 * <li> A newline (line feed) character ({@code '\n'}),
461 *
462 * <li> A carriage-return character followed immediately by a newline
463 * character ({@code "\r\n"}),
464 *
465 * <li> A standalone carriage-return character ({@code '\r'}),
466 *
467 * <li> A next-line character (<code>'\u0085'</code>),
468 *
469 * <li> A line-separator character (<code>'\u2028'</code>), or
470 *
471 * <li> A paragraph-separator character (<code>'\u2029'</code>).
472 *
473 * </ul>
474 * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators
475 * recognized are newline characters.
476 *
477 * <p> The regular expression {@code .} matches any character except a line
478 * terminator unless the {@link #DOTALL} flag is specified.
479 *
480 * <p> By default, the regular expressions {@code ^} and {@code $} ignore
481 * line terminators and only match at the beginning and the end, respectively,
482 * of the entire input sequence. If {@link #MULTILINE} mode is activated then
483 * {@code ^} matches at the beginning of input and after any line terminator
484 * except at the end of input. When in {@link #MULTILINE} mode {@code $}
485 * matches just before a line terminator or the end of the input sequence.
486 *
487 * <h2><a id="cg">Groups and capturing</a></h2>
488 *
489 * <h3><a id="gnumber">Group number</a></h3>
490 * <p> Capturing groups are numbered by counting their opening parentheses from
491 * left to right. In the expression {@code ((A)(B(C)))}, for example, there
492 * are four such groups: </p>
493 *
494 * <ol style="margin-left:2em;">
495 * <li> {@code ((A)(B(C)))}
496 * <li> {@code (A)}
497 * <li> {@code (B(C))}
498 * <li> {@code (C)}
499 * </ol>
500 *
501 * <p> Group zero always stands for the entire expression.
502 *
503 * <p> Capturing groups are so named because, during a match, each subsequence
504 * of the input sequence that matches such a group is saved. The captured
505 * subsequence may be used later in the expression, via a back reference, and
506 * may also be retrieved from the matcher once the match operation is complete.
507 *
508 * <h3><a id="groupname">Group name</a></h3>
509 * <p>A capturing group can also be assigned a "name", a {@code named-capturing group},
510 * and then be back-referenced later by the "name". Group names are composed of
511 * the following characters. The first character must be a {@code letter}.
512 *
513 * <ul>
514 * <li> The uppercase letters {@code 'A'} through {@code 'Z'}
515 * (<code>'\u0041'</code> through <code>'\u005a'</code>),
516 * <li> The lowercase letters {@code 'a'} through {@code 'z'}
517 * (<code>'\u0061'</code> through <code>'\u007a'</code>),
518 * <li> The digits {@code '0'} through {@code '9'}
519 * (<code>'\u0030'</code> through <code>'\u0039'</code>),
520 * </ul>
521 *
522 * <p> A {@code named-capturing group} is still numbered as described in
523 * <a href="#gnumber">Group number</a>.
524 *
525 * <p> The captured input associated with a group is always the subsequence
526 * that the group most recently matched. If a group is evaluated a second time
527 * because of quantification then its previously-captured value, if any, will
528 * be retained if the second evaluation fails. Matching the string
529 * {@code "aba"} against the expression {@code (a(b)?)+}, for example, leaves
530 * group two set to {@code "b"}. All captured input is discarded at the
531 * beginning of each match.
532 *
533 * <p> Groups beginning with {@code (?} are either pure, <i>non-capturing</i> groups
534 * that do not capture text and do not count towards the group total, or
535 * <i>named-capturing</i> group.
536 *
537 * <h2> Unicode support </h2>
538 *
539 * <p> This class is in conformance with Level 1 of <a
540 * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
541 * Standard #18: Unicode Regular Expression</i></a>, plus RL2.1
542 * Canonical Equivalents.
543 * <p>
544 * <b>Unicode escape sequences</b> such as <code>\u2014</code> in Java source code
545 * are processed as described in section 3.3 of
546 * <cite>The Java™ Language Specification</cite>.
547 * Such escape sequences are also implemented directly by the regular-expression
548 * parser so that Unicode escapes can be used in expressions that are read from
549 * files or from the keyboard. Thus the strings <code>"\u2014"</code> and
550 * {@code "\\u2014"}, while not equal, compile into the same pattern, which
551 * matches the character with hexadecimal value {@code 0x2014}.
552 * <p>
553 * A Unicode character can also be represented by using its <b>Hex notation</b>
554 * (hexadecimal code point value) directly as described in construct
555 * <code>\x{...}</code>, for example a supplementary character U+2011F can be
556 * specified as <code>\x{2011F}</code>, instead of two consecutive Unicode escape
557 * sequences of the surrogate pair <code>\uD840</code><code>\uDD1F</code>.
558 * <p>
559 * <b>Unicode character names</b> are supported by the named character construct
560 * <code>\N{</code>...<code>}</code>, for example, <code>\N{WHITE SMILING FACE}</code>
561 * specifies character <code>\u263A</code>. The character names supported
562 * by this class are the valid Unicode character names matched by
563 * {@link java.lang.Character#codePointOf(String) Character.codePointOf(name)}.
564 * <p>
565 * <a href="http://www.unicode.org/reports/tr18/#Default_Grapheme_Clusters">
566 * <b>Unicode extended grapheme clusters</b></a> are supported by the grapheme
567 * cluster matcher {@code \X} and the corresponding boundary matcher {@code \b{g}}.
568 * <p>
569 * Unicode scripts, blocks, categories and binary properties are written with
570 * the {@code \p} and {@code \P} constructs as in Perl.
571 * <code>\p{</code><i>prop</i><code>}</code> matches if
572 * the input has the property <i>prop</i>, while <code>\P{</code><i>prop</i><code>}</code>
573 * does not match if the input has that property.
574 * <p>
575 * Scripts, blocks, categories and binary properties can be used both inside
576 * and outside of a character class.
577 *
578 * <p>
579 * <b><a id="usc">Scripts</a></b> are specified either with the prefix {@code Is}, as in
580 * {@code IsHiragana}, or by using the {@code script} keyword (or its short
581 * form {@code sc}) as in {@code script=Hiragana} or {@code sc=Hiragana}.
582 * <p>
583 * The script names supported by {@code Pattern} are the valid script names
584 * accepted and defined by
585 * {@link java.lang.Character.UnicodeScript#forName(String) UnicodeScript.forName}.
586 *
587 * <p>
588 * <b><a id="ubc">Blocks</a></b> are specified with the prefix {@code In}, as in
589 * {@code InMongolian}, or by using the keyword {@code block} (or its short
590 * form {@code blk}) as in {@code block=Mongolian} or {@code blk=Mongolian}.
591 * <p>
592 * The block names supported by {@code Pattern} are the valid block names
593 * accepted and defined by
594 * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}.
595 * <p>
596 *
597 * <b><a id="ucc">Categories</a></b> may be specified with the optional prefix {@code Is}:
598 * Both {@code \p{L}} and {@code \p{IsL}} denote the category of Unicode
599 * letters. Same as scripts and blocks, categories can also be specified
600 * by using the keyword {@code general_category} (or its short form
601 * {@code gc}) as in {@code general_category=Lu} or {@code gc=Lu}.
602 * <p>
603 * The supported categories are those of
604 * <a href="http://www.unicode.org/unicode/standard/standard.html">
605 * <i>The Unicode Standard</i></a> in the version specified by the
606 * {@link java.lang.Character Character} class. The category names are those
607 * defined in the Standard, both normative and informative.
608 * <p>
609 *
610 * <b><a id="ubpc">Binary properties</a></b> are specified with the prefix {@code Is}, as in
611 * {@code IsAlphabetic}. The supported binary properties by {@code Pattern}
612 * are
613 * <ul>
614 * <li> Alphabetic
615 * <li> Ideographic
616 * <li> Letter
617 * <li> Lowercase
618 * <li> Uppercase
619 * <li> Titlecase
620 * <li> Punctuation
621 * <Li> Control
622 * <li> White_Space
623 * <li> Digit
624 * <li> Hex_Digit
625 * <li> Join_Control
626 * <li> Noncharacter_Code_Point
627 * <li> Assigned
628 * </ul>
629 * <p>
630 * The following <b>Predefined Character classes</b> and <b>POSIX character classes</b>
631 * are in conformance with the recommendation of <i>Annex C: Compatibility Properties</i>
632 * of <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Regular Expression
633 * </i></a>, when {@link #UNICODE_CHARACTER_CLASS} flag is specified.
634 *
635 * <table class="striped">
636 * <caption style="display:none">predefined and posix character classes in Unicode mode</caption>
637 * <thead>
638 * <tr>
639 * <th scope="col" id="predef_classes">Classes</th>
640 * <th scope="col" id="predef_matches">Matches</th>
641 * </tr>
642 * </thead>
643 * <tbody>
644 * <tr><th scope="row">{@code \p{Lower}}</th>
645 * <td>A lowercase character:{@code \p{IsLowercase}}</td></tr>
646 * <tr><th scope="row">{@code \p{Upper}}</th>
647 * <td>An uppercase character:{@code \p{IsUppercase}}</td></tr>
648 * <tr><th scope="row">{@code \p{ASCII}}</th>
649 * <td>All ASCII:{@code [\x00-\x7F]}</td></tr>
650 * <tr><th scope="row">{@code \p{Alpha}}</th>
651 * <td>An alphabetic character:{@code \p{IsAlphabetic}}</td></tr>
652 * <tr><th scope="row">{@code \p{Digit}}</th>
653 * <td>A decimal digit character:{@code \p{IsDigit}}</td></tr>
654 * <tr><th scope="row">{@code \p{Alnum}}</th>
655 * <td>An alphanumeric character:{@code [\p{IsAlphabetic}\p{IsDigit}]}</td></tr>
656 * <tr><th scope="row">{@code \p{Punct}}</th>
657 * <td>A punctuation character:{@code \p{IsPunctuation}}</td></tr>
658 * <tr><th scope="row">{@code \p{Graph}}</th>
659 * <td>A visible character: {@code [^\p{IsWhite_Space}\p{gc=Cc}\p{gc=Cs}\p{gc=Cn}]}</td></tr>
660 * <tr><th scope="row">{@code \p{Print}}</th>
661 * <td>A printable character: {@code [\p{Graph}\p{Blank}&&[^\p{Cntrl}]]}</td></tr>
662 * <tr><th scope="row">{@code \p{Blank}}</th>
663 * <td>A space or a tab: {@code [\p{IsWhite_Space}&&[^\p{gc=Zl}\p{gc=Zp}\x0a\x0b\x0c\x0d\x85]]}</td></tr>
664 * <tr><th scope="row">{@code \p{Cntrl}}</th>
665 * <td>A control character: {@code \p{gc=Cc}}</td></tr>
666 * <tr><th scope="row">{@code \p{XDigit}}</th>
667 * <td>A hexadecimal digit: {@code [\p{gc=Nd}\p{IsHex_Digit}]}</td></tr>
668 * <tr><th scope="row">{@code \p{Space}}</th>
669 * <td>A whitespace character:{@code \p{IsWhite_Space}}</td></tr>
670 * <tr><th scope="row">{@code \d}</th>
671 * <td>A digit: {@code \p{IsDigit}}</td></tr>
672 * <tr><th scope="row">{@code \D}</th>
673 * <td>A non-digit: {@code [^\d]}</td></tr>
674 * <tr><th scope="row">{@code \s}</th>
675 * <td>A whitespace character: {@code \p{IsWhite_Space}}</td></tr>
676 * <tr><th scope="row">{@code \S}</th>
677 * <td>A non-whitespace character: {@code [^\s]}</td></tr>
678 * <tr><th scope="row">{@code \w}</th>
679 * <td>A word character: {@code [\p{Alpha}\p{gc=Mn}\p{gc=Me}\p{gc=Mc}\p{Digit}\p{gc=Pc}\p{IsJoin_Control}]}</td></tr>
680 * <tr><th scope="row">{@code \W}</th>
681 * <td>A non-word character: {@code [^\w]}</td></tr>
682 * </tbody>
683 * </table>
684 * <p>
685 * <a id="jcc">
686 * Categories that behave like the java.lang.Character
687 * boolean is<i>methodname</i> methods (except for the deprecated ones) are
688 * available through the same <code>\p{</code><i>prop</i><code>}</code> syntax where
689 * the specified property has the name <code>java<i>methodname</i></code></a>.
690 *
691 * <h2> Comparison to Perl 5 </h2>
692 *
693 * <p>The {@code Pattern} engine performs traditional NFA-based matching
694 * with ordered alternation as occurs in Perl 5.
695 *
696 * <p> Perl constructs not supported by this class: </p>
697 *
698 * <ul>
699 * <li><p> The backreference constructs, <code>\g{</code><i>n</i><code>}</code> for
700 * the <i>n</i><sup>th</sup><a href="#cg">capturing group</a> and
701 * <code>\g{</code><i>name</i><code>}</code> for
702 * <a href="#groupname">named-capturing group</a>.
703 * </p></li>
704 *
705 * <li><p> The conditional constructs
706 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code )} and
707 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code |}<i>Y</i>{@code )},
708 * </p></li>
709 *
710 * <li><p> The embedded code constructs <code>(?{</code><i>code</i><code>})</code>
711 * and <code>(??{</code><i>code</i><code>})</code>,</p></li>
712 *
713 * <li><p> The embedded comment syntax {@code (?#comment)}, and </p></li>
714 *
715 * <li><p> The preprocessing operations {@code \l} <code>\u</code>,
716 * {@code \L}, and {@code \U}. </p></li>
717 *
718 * </ul>
719 *
720 * <p> Constructs supported by this class but not by Perl: </p>
721 *
722 * <ul>
723 *
724 * <li><p> Character-class union and intersection as described
725 * <a href="#cc">above</a>.</p></li>
726 *
727 * </ul>
728 *
729 * <p> Notable differences from Perl: </p>
730 *
731 * <ul>
732 *
733 * <li><p> In Perl, {@code \1} through {@code \9} are always interpreted
734 * as back references; a backslash-escaped number greater than {@code 9} is
735 * treated as a back reference if at least that many subexpressions exist,
736 * otherwise it is interpreted, if possible, as an octal escape. In this
737 * class octal escapes must always begin with a zero. In this class,
738 * {@code \1} through {@code \9} are always interpreted as back
739 * references, and a larger number is accepted as a back reference if at
740 * least that many subexpressions exist at that point in the regular
741 * expression, otherwise the parser will drop digits until the number is
742 * smaller or equal to the existing number of groups or it is one digit.
743 * </p></li>
744 *
745 * <li><p> Perl uses the {@code g} flag to request a match that resumes
746 * where the last match left off. This functionality is provided implicitly
747 * by the {@link Matcher} class: Repeated invocations of the {@link
748 * Matcher#find find} method will resume where the last match left off,
749 * unless the matcher is reset. </p></li>
750 *
751 * <li><p> In Perl, embedded flags at the top level of an expression affect
752 * the whole expression. In this class, embedded flags always take effect
753 * at the point at which they appear, whether they are at the top level or
754 * within a group; in the latter case, flags are restored at the end of the
755 * group just as in Perl. </p></li>
756 *
757 * </ul>
758 *
759 *
760 * <p> For a more precise description of the behavior of regular expression
761 * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/">
762 * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl,
763 * O'Reilly and Associates, 2006.</a>
764 * </p>
765 *
766 * @see java.lang.String#split(String, int)
767 * @see java.lang.String#split(String)
768 *
769 * @author Mike McCloskey
770 * @author Mark Reinhold
771 * @author JSR-51 Expert Group
772 * @since 1.4
773 * @spec JSR-51
774 */
775
776 public final class Pattern
777 implements java.io.Serializable
778 {
779
780 /**
781 * Regular expression modifier values. Instead of being passed as
782 * arguments, they can also be passed as inline modifiers.
783 * For example, the following statements have the same effect.
784 * <pre>
785 * Pattern p1 = Pattern.compile("abc", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE);
786 * Pattern p2 = Pattern.compile("(?im)abc", 0);
787 * </pre>
788 */
789
790 /**
791 * Enables Unix lines mode.
792 *
793 * <p> In this mode, only the {@code '\n'} line terminator is recognized
794 * in the behavior of {@code .}, {@code ^}, and {@code $}.
795 *
796 * <p> Unix lines mode can also be enabled via the embedded flag
797 * expression {@code (?d)}.
798 */
799 public static final int UNIX_LINES = 0x01;
800
801 /**
802 * Enables case-insensitive matching.
803 *
804 * <p> By default, case-insensitive matching assumes that only characters
805 * in the US-ASCII charset are being matched. Unicode-aware
806 * case-insensitive matching can be enabled by specifying the {@link
807 * #UNICODE_CASE} flag in conjunction with this flag.
808 *
809 * <p> Case-insensitive matching can also be enabled via the embedded flag
810 * expression {@code (?i)}.
811 *
812 * <p> Specifying this flag may impose a slight performance penalty. </p>
813 */
814 public static final int CASE_INSENSITIVE = 0x02;
815
816 /**
817 * Permits whitespace and comments in pattern.
818 *
819 * <p> In this mode, whitespace is ignored, and embedded comments starting
820 * with {@code #} are ignored until the end of a line.
821 *
822 * <p> Comments mode can also be enabled via the embedded flag
823 * expression {@code (?x)}.
824 */
825 public static final int COMMENTS = 0x04;
826
827 /**
828 * Enables multiline mode.
829 *
830 * <p> In multiline mode the expressions {@code ^} and {@code $} match
831 * just after or just before, respectively, a line terminator or the end of
832 * the input sequence. By default these expressions only match at the
833 * beginning and the end of the entire input sequence.
834 *
835 * <p> Multiline mode can also be enabled via the embedded flag
836 * expression {@code (?m)}. </p>
837 */
838 public static final int MULTILINE = 0x08;
839
840 /**
841 * Enables literal parsing of the pattern.
842 *
843 * <p> When this flag is specified then the input string that specifies
844 * the pattern is treated as a sequence of literal characters.
845 * Metacharacters or escape sequences in the input sequence will be
846 * given no special meaning.
847 *
848 * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on
849 * matching when used in conjunction with this flag. The other flags
850 * become superfluous.
851 *
852 * <p> There is no embedded flag character for enabling literal parsing.
853 * @since 1.5
854 */
855 public static final int LITERAL = 0x10;
856
857 /**
858 * Enables dotall mode.
859 *
860 * <p> In dotall mode, the expression {@code .} matches any character,
861 * including a line terminator. By default this expression does not match
862 * line terminators.
863 *
864 * <p> Dotall mode can also be enabled via the embedded flag
865 * expression {@code (?s)}. (The {@code s} is a mnemonic for
866 * "single-line" mode, which is what this is called in Perl.) </p>
867 */
868 public static final int DOTALL = 0x20;
869
870 /**
871 * Enables Unicode-aware case folding.
872 *
873 * <p> When this flag is specified then case-insensitive matching, when
874 * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner
875 * consistent with the Unicode Standard. By default, case-insensitive
876 * matching assumes that only characters in the US-ASCII charset are being
877 * matched.
878 *
879 * <p> Unicode-aware case folding can also be enabled via the embedded flag
880 * expression {@code (?u)}.
881 *
882 * <p> Specifying this flag may impose a performance penalty. </p>
883 */
884 public static final int UNICODE_CASE = 0x40;
885
886 /**
887 * Enables canonical equivalence.
888 *
889 * <p> When this flag is specified then two characters will be considered
890 * to match if, and only if, their full canonical decompositions match.
891 * The expression <code>"a\u030A"</code>, for example, will match the
892 * string <code>"\u00E5"</code> when this flag is specified. By default,
893 * matching does not take canonical equivalence into account.
894 *
895 * <p> There is no embedded flag character for enabling canonical
896 * equivalence.
897 *
898 * <p> Specifying this flag may impose a performance penalty. </p>
899 */
900 public static final int CANON_EQ = 0x80;
901
902 /**
903 * Enables the Unicode version of <i>Predefined character classes</i> and
904 * <i>POSIX character classes</i>.
905 *
906 * <p> When this flag is specified then the (US-ASCII only)
907 * <i>Predefined character classes</i> and <i>POSIX character classes</i>
908 * are in conformance with
909 * <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
910 * Standard #18: Unicode Regular Expression</i></a>
911 * <i>Annex C: Compatibility Properties</i>.
912 * <p>
913 * The UNICODE_CHARACTER_CLASS mode can also be enabled via the embedded
914 * flag expression {@code (?U)}.
915 * <p>
916 * The flag implies UNICODE_CASE, that is, it enables Unicode-aware case
917 * folding.
918 * <p>
919 * Specifying this flag may impose a performance penalty. </p>
920 * @since 1.7
921 */
922 public static final int UNICODE_CHARACTER_CLASS = 0x100;
923
924 /**
925 * Contains all possible flags for compile(regex, flags).
926 */
927 private static final int ALL_FLAGS = CASE_INSENSITIVE | MULTILINE |
928 DOTALL | UNICODE_CASE | CANON_EQ | UNIX_LINES | LITERAL |
929 UNICODE_CHARACTER_CLASS | COMMENTS;
930
931 /* Pattern has only two serialized components: The pattern string
932 * and the flags, which are all that is needed to recompile the pattern
933 * when it is deserialized.
934 */
935
936 /** use serialVersionUID from Merlin b59 for interoperability */
937 private static final long serialVersionUID = 5073258162644648461L;
938
939 /**
940 * The original regular-expression pattern string.
941 *
942 * @serial
943 */
944 private String pattern;
945
946 /**
947 * The original pattern flags.
948 *
949 * @serial
950 */
951 private int flags;
952
953 /**
954 * The temporary pattern flags used during compiling. The flags might be turn
955 * on and off by embedded flag.
956 */
957 private transient int flags0;
958
959 /**
960 * Boolean indicating this Pattern is compiled; this is necessary in order
961 * to lazily compile deserialized Patterns.
962 */
963 private transient volatile boolean compiled;
964
965 /**
966 * The normalized pattern string.
967 */
968 private transient String normalizedPattern;
969
970 /**
971 * The starting point of state machine for the find operation. This allows
972 * a match to start anywhere in the input.
973 */
974 transient Node root;
975
976 /**
977 * The root of object tree for a match operation. The pattern is matched
978 * at the beginning. This may include a find that uses BnM or a First
979 * node.
980 */
981 transient Node matchRoot;
982
983 /**
984 * Temporary storage used by parsing pattern slice.
985 */
986 transient int[] buffer;
987
988 /**
989 * A temporary storage used for predicate for double return.
990 */
991 transient CharPredicate predicate;
992
993 /**
994 * Map the "name" of the "named capturing group" to its group id
995 * node.
996 */
997 transient volatile Map<String, Integer> namedGroups;
998
999 /**
1000 * Temporary storage used while parsing group references.
1001 */
1002 transient GroupHead[] groupNodes;
1003
1004 /**
1005 * Temporary storage used to store the top level closure nodes.
1006 */
1007 transient List<Node> topClosureNodes;
1008
1009 /**
1010 * The number of top greedy closure nodes in this Pattern. Used by
1011 * matchers to allocate storage needed for a IntHashSet to keep the
1012 * beginning pos {@code i} of all failed match.
1013 */
1014 transient int localTCNCount;
1015
1016 /*
1017 * Turn off the stop-exponential-backtracking optimization if there
1018 * is a group ref in the pattern.
1019 */
1020 transient boolean hasGroupRef;
1021
1022 /**
1023 * Temporary null terminated code point array used by pattern compiling.
1024 */
1025 private transient int[] temp;
1026
1027 /**
1028 * The number of capturing groups in this Pattern. Used by matchers to
1029 * allocate storage needed to perform a match.
1030 */
1031 transient int capturingGroupCount;
1032
1033 /**
1034 * The local variable count used by parsing tree. Used by matchers to
1035 * allocate storage needed to perform a match.
1036 */
1037 transient int localCount;
1038
1039 /**
1040 * Index into the pattern string that keeps track of how much has been
1041 * parsed.
1042 */
1043 private transient int cursor;
1044
1045 /**
1046 * Holds the length of the pattern string.
1047 */
1048 private transient int patternLength;
1049
1050 /**
1051 * If the Start node might possibly match supplementary characters.
1052 * It is set to true during compiling if
1053 * (1) There is supplementary char in pattern, or
1054 * (2) There is complement node of a "family" CharProperty
1055 */
1056 private transient boolean hasSupplementary;
1057
1058 /**
1059 * Compiles the given regular expression into a pattern.
1060 *
1061 * @param regex
1062 * The expression to be compiled
1063 * @return the given regular expression compiled into a pattern
1064 * @throws PatternSyntaxException
1065 * If the expression's syntax is invalid
1066 */
1067 public static Pattern compile(String regex) {
1068 return new Pattern(regex, 0);
1069 }
1070
1071 /**
1072 * Compiles the given regular expression into a pattern with the given
1073 * flags.
1074 *
1075 * @param regex
1076 * The expression to be compiled
1077 *
1078 * @param flags
1079 * Match flags, a bit mask that may include
1080 * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
1081 * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
1082 * {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS}
1083 * and {@link #COMMENTS}
1084 *
1085 * @return the given regular expression compiled into a pattern with the given flags
1086 * @throws IllegalArgumentException
1087 * If bit values other than those corresponding to the defined
1088 * match flags are set in {@code flags}
1089 *
1090 * @throws PatternSyntaxException
1091 * If the expression's syntax is invalid
1092 */
1093 public static Pattern compile(String regex, int flags) {
1094 return new Pattern(regex, flags);
1095 }
1096
1097 /**
1098 * Returns the regular expression from which this pattern was compiled.
1099 *
1100 * @return The source of this pattern
1101 */
1102 public String pattern() {
1103 return pattern;
1104 }
1105
1106 /**
1107 * <p>Returns the string representation of this pattern. This
1108 * is the regular expression from which this pattern was
1109 * compiled.</p>
1110 *
1111 * @return The string representation of this pattern
1112 * @since 1.5
1113 */
1114 public String toString() {
1115 return pattern;
1116 }
1117
1118 /**
1119 * Creates a matcher that will match the given input against this pattern.
1120 *
1121 * @param input
1122 * The character sequence to be matched
1123 *
1124 * @return A new matcher for this pattern
1125 */
1126 public Matcher matcher(CharSequence input) {
1127 if (!compiled) {
1128 synchronized(this) {
1129 if (!compiled)
1130 compile();
1131 }
1132 }
1133 Matcher m = new Matcher(this, input);
1134 return m;
1135 }
1136
1137 /**
1138 * Returns this pattern's match flags.
1139 *
1140 * @return The match flags specified when this pattern was compiled
1141 */
1142 public int flags() {
1143 return flags0;
1144 }
1145
1146 /**
1147 * Compiles the given regular expression and attempts to match the given
1148 * input against it.
1149 *
1150 * <p> An invocation of this convenience method of the form
1151 *
1152 * <blockquote><pre>
1153 * Pattern.matches(regex, input);</pre></blockquote>
1154 *
1155 * behaves in exactly the same way as the expression
1156 *
1157 * <blockquote><pre>
1158 * Pattern.compile(regex).matcher(input).matches()</pre></blockquote>
1159 *
1160 * <p> If a pattern is to be used multiple times, compiling it once and reusing
1161 * it will be more efficient than invoking this method each time. </p>
1162 *
1163 * @param regex
1164 * The expression to be compiled
1165 *
1166 * @param input
1167 * The character sequence to be matched
1168 * @return whether or not the regular expression matches on the input
1169 * @throws PatternSyntaxException
1170 * If the expression's syntax is invalid
1171 */
1172 public static boolean matches(String regex, CharSequence input) {
1173 Pattern p = Pattern.compile(regex);
1174 Matcher m = p.matcher(input);
1175 return m.matches();
1176 }
1177
1178 /**
1179 * Splits the given input sequence around matches of this pattern.
1180 *
1181 * <p> The array returned by this method contains each substring of the
1182 * input sequence that is terminated by another subsequence that matches
1183 * this pattern or is terminated by the end of the input sequence. The
1184 * substrings in the array are in the order in which they occur in the
1185 * input. If this pattern does not match any subsequence of the input then
1186 * the resulting array has just one element, namely the input sequence in
1187 * string form.
1188 *
1189 * <p> When there is a positive-width match at the beginning of the input
1190 * sequence then an empty leading substring is included at the beginning
1191 * of the resulting array. A zero-width match at the beginning however
1192 * never produces such empty leading substring.
1193 *
1194 * <p> The {@code limit} parameter controls the number of times the
1195 * pattern is applied and therefore affects the length of the resulting
1196 * array.
1197 * <ul>
1198 * <li><p>
1199 * If the <i>limit</i> is positive then the pattern will be applied
1200 * at most <i>limit</i> - 1 times, the array's length will be
1201 * no greater than <i>limit</i>, and the array's last entry will contain
1202 * all input beyond the last matched delimiter.</p></li>
1203 *
1204 * <li><p>
1205 * If the <i>limit</i> is zero then the pattern will be applied as
1206 * many times as possible, the array can have any length, and trailing
1207 * empty strings will be discarded.</p></li>
1208 *
1209 * <li><p>
1210 * If the <i>limit</i> is negative then the pattern will be applied
1211 * as many times as possible and the array can have any length.</p></li>
1212 * </ul>
1213 *
1214 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1215 * results with these parameters:
1216 *
1217 * <table class="plain" style="margin-left:2em;">
1218 * <caption style="display:none">Split example showing regex, limit, and result</caption>
1219 * <thead>
1220 * <tr>
1221 * <th scope="col">Regex</th>
1222 * <th scope="col">Limit</th>
1223 * <th scope="col">Result</th>
1224 * </tr>
1225 * </thead>
1226 * <tbody>
1227 * <tr><th scope="row" rowspan="3" style="font-weight:normal">:</th>
1228 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">2</th>
1229 * <td>{@code { "boo", "and:foo" }}</td></tr>
1230 * <tr><!-- : -->
1231 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th>
1232 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1233 * <tr><!-- : -->
1234 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th>
1235 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1236 * <tr><th scope="row" rowspan="3" style="font-weight:normal">o</th>
1237 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">5</th>
1238 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1239 * <tr><!-- o -->
1240 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">-2</th>
1241 * <td>{@code { "b", "", ":and:f", "", "" }}</td></tr>
1242 * <tr><!-- o -->
1243 * <th scope="row" style="font-weight:normal; text-align:right; padding-right:1em">0</th>
1244 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1245 * </tbody>
1246 * </table>
1247 *
1248 * @param input
1249 * The character sequence to be split
1250 *
1251 * @param limit
1252 * The result threshold, as described above
1253 *
1254 * @return The array of strings computed by splitting the input
1255 * around matches of this pattern
1256 */
1257 public String[] split(CharSequence input, int limit) {
1258 int index = 0;
1259 boolean matchLimited = limit > 0;
1260 ArrayList<String> matchList = new ArrayList<>();
1261 Matcher m = matcher(input);
1262
1263 // Add segments before each match found
1264 while(m.find()) {
1265 if (!matchLimited || matchList.size() < limit - 1) {
1266 if (index == 0 && index == m.start() && m.start() == m.end()) {
1267 // no empty leading substring included for zero-width match
1268 // at the beginning of the input char sequence.
1269 continue;
1270 }
1271 String match = input.subSequence(index, m.start()).toString();
1272 matchList.add(match);
1273 index = m.end();
1274 } else if (matchList.size() == limit - 1) { // last one
1275 String match = input.subSequence(index,
1276 input.length()).toString();
1277 matchList.add(match);
1278 index = m.end();
1279 }
1280 }
1281
1282 // If no match was found, return this
1283 if (index == 0)
1284 return new String[] {input.toString()};
1285
1286 // Add remaining segment
1287 if (!matchLimited || matchList.size() < limit)
1288 matchList.add(input.subSequence(index, input.length()).toString());
1289
1290 // Construct result
1291 int resultSize = matchList.size();
1292 if (limit == 0)
1293 while (resultSize > 0 && matchList.get(resultSize-1).isEmpty())
1294 resultSize--;
1295 String[] result = new String[resultSize];
1296 return matchList.subList(0, resultSize).toArray(result);
1297 }
1298
1299 /**
1300 * Splits the given input sequence around matches of this pattern.
1301 *
1302 * <p> This method works as if by invoking the two-argument {@link
1303 * #split(java.lang.CharSequence, int) split} method with the given input
1304 * sequence and a limit argument of zero. Trailing empty strings are
1305 * therefore not included in the resulting array. </p>
1306 *
1307 * <p> The input {@code "boo:and:foo"}, for example, yields the following
1308 * results with these expressions:
1309 *
1310 * <table class="plain" style="margin-left:2em">
1311 * <caption style="display:none">Split examples showing regex and result</caption>
1312 * <thead>
1313 * <tr>
1314 * <th scope="col">Regex</th>
1315 * <th scope="col">Result</th>
1316 * </tr>
1317 * </thead>
1318 * <tbody>
1319 * <tr><th scope="row" style="text-weight:normal">:</th>
1320 * <td>{@code { "boo", "and", "foo" }}</td></tr>
1321 * <tr><th scope="row" style="text-weight:normal">o</th>
1322 * <td>{@code { "b", "", ":and:f" }}</td></tr>
1323 * </tbody>
1324 * </table>
1325 *
1326 *
1327 * @param input
1328 * The character sequence to be split
1329 *
1330 * @return The array of strings computed by splitting the input
1331 * around matches of this pattern
1332 */
1333 public String[] split(CharSequence input) {
1334 return split(input, 0);
1335 }
1336
1337 /**
1338 * Returns a literal pattern {@code String} for the specified
1339 * {@code String}.
1340 *
1341 * <p>This method produces a {@code String} that can be used to
1342 * create a {@code Pattern} that would match the string
1343 * {@code s} as if it were a literal pattern.</p> Metacharacters
1344 * or escape sequences in the input sequence will be given no special
1345 * meaning.
1346 *
1347 * @param s The string to be literalized
1348 * @return A literal string replacement
1349 * @since 1.5
1350 */
1351 public static String quote(String s) {
1352 int slashEIndex = s.indexOf("\\E");
1353 if (slashEIndex == -1)
1354 return "\\Q" + s + "\\E";
1355
1356 int lenHint = s.length();
1357 lenHint = (lenHint < Integer.MAX_VALUE - 8 - lenHint) ?
1358 (lenHint << 1) : (Integer.MAX_VALUE - 8);
1359
1360 StringBuilder sb = new StringBuilder(lenHint);
1361 sb.append("\\Q");
1362 int current = 0;
1363 do {
1364 sb.append(s, current, slashEIndex)
1365 .append("\\E\\\\E\\Q");
1366 current = slashEIndex + 2;
1367 } while ((slashEIndex = s.indexOf("\\E", current)) != -1);
1368
1369 return sb.append(s, current, s.length())
1370 .append("\\E")
1371 .toString();
1372 }
1373
1374 /**
1375 * Recompile the Pattern instance from a stream. The original pattern
1376 * string is read in and the object tree is recompiled from it.
1377 */
1378 private void readObject(java.io.ObjectInputStream s)
1379 throws java.io.IOException, ClassNotFoundException {
1380
1381 // Read in all fields
1382 s.defaultReadObject();
1383
1384 // reset the flags
1385 flags0 = flags;
1386
1387 // Initialize counts
1388 capturingGroupCount = 1;
1389 localCount = 0;
1390 localTCNCount = 0;
1391
1392 // if length > 0, the Pattern is lazily compiled
1393 if (pattern.isEmpty()) {
1394 root = new Start(lastAccept);
1395 matchRoot = lastAccept;
1396 compiled = true;
1397 }
1398 }
1399
1400 /**
1401 * This private constructor is used to create all Patterns. The pattern
1402 * string and match flags are all that is needed to completely describe
1403 * a Pattern. An empty pattern string results in an object tree with
1404 * only a Start node and a LastNode node.
1405 */
1406 private Pattern(String p, int f) {
1407 if ((f & ~ALL_FLAGS) != 0) {
1408 throw new IllegalArgumentException("Unknown flag 0x"
1409 + Integer.toHexString(f));
1410 }
1411 pattern = p;
1412 flags = f;
1413
1414 // to use UNICODE_CASE if UNICODE_CHARACTER_CLASS present
1415 if ((flags & UNICODE_CHARACTER_CLASS) != 0)
1416 flags |= UNICODE_CASE;
1417
1418 // 'flags' for compiling
1419 flags0 = flags;
1420
1421 // Reset group index count
1422 capturingGroupCount = 1;
1423 localCount = 0;
1424 localTCNCount = 0;
1425
1426 if (!pattern.isEmpty()) {
1427 compile();
1428 } else {
1429 root = new Start(lastAccept);
1430 matchRoot = lastAccept;
1431 }
1432 }
1433
1434 /**
1435 * The pattern is converted to normalized form ({@link
1436 * java.text.Normalizer.Form#NFC NFC}, canonical decomposition,
1437 * followed by canonical composition for the character class
1438 * part, and {@link java.text.Normalizer.Form#NFD NFD},
1439 * canonical decomposition for the rest), and then a pure
1440 * group is constructed to match canonical equivalences of the
1441 * characters.
1442 */
1443 private static String normalize(String pattern) {
1444 int plen = pattern.length();
1445 StringBuilder pbuf = new StringBuilder(plen);
1446 char last = 0;
1447 int lastStart = 0;
1448 char cc = 0;
1449 for (int i = 0; i < plen;) {
1450 char c = pattern.charAt(i);
1451 if (cc == 0 && // top level
1452 c == '\\' && i + 1 < plen && pattern.charAt(i + 1) == '\\') {
1453 i += 2; last = 0;
1454 continue;
1455 }
1456 if (c == '[' && last != '\\') {
1457 if (cc == 0) {
1458 if (lastStart < i)
1459 normalizeSlice(pattern, lastStart, i, pbuf);
1460 lastStart = i;
1461 }
1462 cc++;
1463 } else if (c == ']' && last != '\\') {
1464 cc--;
1465 if (cc == 0) {
1466 normalizeClazz(pattern, lastStart, i + 1, pbuf);
1467 lastStart = i + 1;
1468 }
1469 }
1470 last = c;
1471 i++;
1472 }
1473 assert (cc == 0);
1474 if (lastStart < plen)
1475 normalizeSlice(pattern, lastStart, plen, pbuf);
1476 return pbuf.toString();
1477 }
1478
1479 private static void normalizeSlice(String src, int off, int limit,
1480 StringBuilder dst)
1481 {
1482 int len = src.length();
1483 int off0 = off;
1484 while (off < limit && ASCII.isAscii(src.charAt(off))) {
1485 off++;
1486 }
1487 if (off == limit) {
1488 dst.append(src, off0, limit);
1489 return;
1490 }
1491 off--;
1492 if (off < off0)
1493 off = off0;
1494 else
1495 dst.append(src, off0, off);
1496 while (off < limit) {
1497 int ch0 = src.codePointAt(off);
1498 if (".$|()[]{}^?*+\\".indexOf(ch0) != -1) {
1499 dst.append((char)ch0);
1500 off++;
1501 continue;
1502 }
1503 int j = off + Character.charCount(ch0);
1504 int ch1;
1505 while (j < limit) {
1506 ch1 = src.codePointAt(j);
1507 if (Grapheme.isBoundary(ch0, ch1))
1508 break;
1509 ch0 = ch1;
1510 j += Character.charCount(ch1);
1511 }
1512 String seq = src.substring(off, j);
1513 String nfd = Normalizer.normalize(seq, Normalizer.Form.NFD);
1514 off = j;
1515 if (nfd.length() > 1) {
1516 ch0 = nfd.codePointAt(0);
1517 ch1 = nfd.codePointAt(Character.charCount(ch0));
1518 if (Character.getType(ch1) == Character.NON_SPACING_MARK) {
1519 Set<String> altns = new LinkedHashSet<>();
1520 altns.add(seq);
1521 produceEquivalentAlternation(nfd, altns);
1522 dst.append("(?:");
1523 altns.forEach( s -> dst.append(s).append('|'));
1524 dst.delete(dst.length() - 1, dst.length());
1525 dst.append(")");
1526 continue;
1527 }
1528 }
1529 String nfc = Normalizer.normalize(seq, Normalizer.Form.NFC);
1530 if (!seq.equals(nfc) && !nfd.equals(nfc))
1531 dst.append("(?:" + seq + "|" + nfd + "|" + nfc + ")");
1532 else if (!seq.equals(nfd))
1533 dst.append("(?:" + seq + "|" + nfd + ")");
1534 else
1535 dst.append(seq);
1536 }
1537 }
1538
1539 private static void normalizeClazz(String src, int off, int limit,
1540 StringBuilder dst)
1541 {
1542 dst.append(Normalizer.normalize(src.substring(off, limit), Form.NFC));
1543 }
1544
1545 /**
1546 * Given a specific sequence composed of a regular character and
1547 * combining marks that follow it, produce the alternation that will
1548 * match all canonical equivalences of that sequence.
1549 */
1550 private static void produceEquivalentAlternation(String src,
1551 Set<String> dst)
1552 {
1553 int len = countChars(src, 0, 1);
1554 if (src.length() == len) {
1555 dst.add(src); // source has one character.
1556 return;
1557 }
1558 String base = src.substring(0,len);
1559 String combiningMarks = src.substring(len);
1560 String[] perms = producePermutations(combiningMarks);
1561 // Add combined permutations
1562 for(int x = 0; x < perms.length; x++) {
1563 String next = base + perms[x];
1564 dst.add(next);
1565 next = composeOneStep(next);
1566 if (next != null) {
1567 produceEquivalentAlternation(next, dst);
1568 }
1569 }
1570 }
1571
1572 /**
1573 * Returns an array of strings that have all the possible
1574 * permutations of the characters in the input string.
1575 * This is used to get a list of all possible orderings
1576 * of a set of combining marks. Note that some of the permutations
1577 * are invalid because of combining class collisions, and these
1578 * possibilities must be removed because they are not canonically
1579 * equivalent.
1580 */
1581 private static String[] producePermutations(String input) {
1582 if (input.length() == countChars(input, 0, 1))
1583 return new String[] {input};
1584
1585 if (input.length() == countChars(input, 0, 2)) {
1586 int c0 = Character.codePointAt(input, 0);
1587 int c1 = Character.codePointAt(input, Character.charCount(c0));
1588 if (getClass(c1) == getClass(c0)) {
1589 return new String[] {input};
1590 }
1591 String[] result = new String[2];
1592 result[0] = input;
1593 StringBuilder sb = new StringBuilder(2);
1594 sb.appendCodePoint(c1);
1595 sb.appendCodePoint(c0);
1596 result[1] = sb.toString();
1597 return result;
1598 }
1599
1600 int length = 1;
1601 int nCodePoints = countCodePoints(input);
1602 for(int x=1; x<nCodePoints; x++)
1603 length = length * (x+1);
1604
1605 String[] temp = new String[length];
1606
1607 int combClass[] = new int[nCodePoints];
1608 for(int x=0, i=0; x<nCodePoints; x++) {
1609 int c = Character.codePointAt(input, i);
1610 combClass[x] = getClass(c);
1611 i += Character.charCount(c);
1612 }
1613
1614 // For each char, take it out and add the permutations
1615 // of the remaining chars
1616 int index = 0;
1617 int len;
1618 // offset maintains the index in code units.
1619 loop: for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
1620 len = countChars(input, offset, 1);
1621 for(int y=x-1; y>=0; y--) {
1622 if (combClass[y] == combClass[x]) {
1623 continue loop;
1624 }
1625 }
1626 StringBuilder sb = new StringBuilder(input);
1627 String otherChars = sb.delete(offset, offset+len).toString();
1628 String[] subResult = producePermutations(otherChars);
1629
1630 String prefix = input.substring(offset, offset+len);
1631 for (String sre : subResult)
1632 temp[index++] = prefix + sre;
1633 }
1634 String[] result = new String[index];
1635 System.arraycopy(temp, 0, result, 0, index);
1636 return result;
1637 }
1638
1639 private static int getClass(int c) {
1640 return sun.text.Normalizer.getCombiningClass(c);
1641 }
1642
1643 /**
1644 * Attempts to compose input by combining the first character
1645 * with the first combining mark following it. Returns a String
1646 * that is the composition of the leading character with its first
1647 * combining mark followed by the remaining combining marks. Returns
1648 * null if the first two characters cannot be further composed.
1649 */
1650 private static String composeOneStep(String input) {
1651 int len = countChars(input, 0, 2);
1652 String firstTwoCharacters = input.substring(0, len);
1653 String result = Normalizer.normalize(firstTwoCharacters, Normalizer.Form.NFC);
1654 if (result.equals(firstTwoCharacters))
1655 return null;
1656 else {
1657 String remainder = input.substring(len);
1658 return result + remainder;
1659 }
1660 }
1661
1662 /**
1663 * Preprocess any \Q...\E sequences in `temp', meta-quoting them.
1664 * See the description of `quotemeta' in perlfunc(1).
1665 */
1666 private void RemoveQEQuoting() {
1667 final int pLen = patternLength;
1668 int i = 0;
1669 while (i < pLen-1) {
1670 if (temp[i] != '\\')
1671 i += 1;
1672 else if (temp[i + 1] != 'Q')
1673 i += 2;
1674 else
1675 break;
1676 }
1677 if (i >= pLen - 1) // No \Q sequence found
1678 return;
1679 int j = i;
1680 i += 2;
1681 int newTempLen;
1682 try {
1683 newTempLen = Math.addExact(j + 2, Math.multiplyExact(3, pLen - i));
1684 } catch (ArithmeticException ae) {
1685 throw new OutOfMemoryError();
1686 }
1687 int[] newtemp = new int[newTempLen];
1688 System.arraycopy(temp, 0, newtemp, 0, j);
1689
1690 boolean inQuote = true;
1691 boolean beginQuote = true;
1692 while (i < pLen) {
1693 int c = temp[i++];
1694 if (!ASCII.isAscii(c) || ASCII.isAlpha(c)) {
1695 newtemp[j++] = c;
1696 } else if (ASCII.isDigit(c)) {
1697 if (beginQuote) {
1698 /*
1699 * A unicode escape \[0xu] could be before this quote,
1700 * and we don't want this numeric char to processed as
1701 * part of the escape.
1702 */
1703 newtemp[j++] = '\\';
1704 newtemp[j++] = 'x';
1705 newtemp[j++] = '3';
1706 }
1707 newtemp[j++] = c;
1708 } else if (c != '\\') {
1709 if (inQuote) newtemp[j++] = '\\';
1710 newtemp[j++] = c;
1711 } else if (inQuote) {
1712 if (temp[i] == 'E') {
1713 i++;
1714 inQuote = false;
1715 } else {
1716 newtemp[j++] = '\\';
1717 newtemp[j++] = '\\';
1718 }
1719 } else {
1720 if (temp[i] == 'Q') {
1721 i++;
1722 inQuote = true;
1723 beginQuote = true;
1724 continue;
1725 } else {
1726 newtemp[j++] = c;
1727 if (i != pLen)
1728 newtemp[j++] = temp[i++];
1729 }
1730 }
1731
1732 beginQuote = false;
1733 }
1734
1735 patternLength = j;
1736 temp = Arrays.copyOf(newtemp, j + 2); // double zero termination
1737 }
1738
1739 /**
1740 * Copies regular expression to an int array and invokes the parsing
1741 * of the expression which will create the object tree.
1742 */
1743 private void compile() {
1744 // Handle canonical equivalences
1745 if (has(CANON_EQ) && !has(LITERAL)) {
1746 normalizedPattern = normalize(pattern);
1747 } else {
1748 normalizedPattern = pattern;
1749 }
1750 patternLength = normalizedPattern.length();
1751
1752 // Copy pattern to int array for convenience
1753 // Use double zero to terminate pattern
1754 temp = new int[patternLength + 2];
1755
1756 hasSupplementary = false;
1757 int c, count = 0;
1758 // Convert all chars into code points
1759 for (int x = 0; x < patternLength; x += Character.charCount(c)) {
1760 c = normalizedPattern.codePointAt(x);
1761 if (isSupplementary(c)) {
1762 hasSupplementary = true;
1763 }
1764 temp[count++] = c;
1765 }
1766
1767 patternLength = count; // patternLength now in code points
1768
1769 if (! has(LITERAL))
1770 RemoveQEQuoting();
1771
1772 // Allocate all temporary objects here.
1773 buffer = new int[32];
1774 groupNodes = new GroupHead[10];
1775 namedGroups = null;
1776 topClosureNodes = new ArrayList<>(10);
1777
1778 if (has(LITERAL)) {
1779 // Literal pattern handling
1780 matchRoot = newSlice(temp, patternLength, hasSupplementary);
1781 matchRoot.next = lastAccept;
1782 } else {
1783 // Start recursive descent parsing
1784 matchRoot = expr(lastAccept);
1785 // Check extra pattern characters
1786 if (patternLength != cursor) {
1787 if (peek() == ')') {
1788 throw error("Unmatched closing ')'");
1789 } else {
1790 throw error("Unexpected internal error");
1791 }
1792 }
1793 }
1794
1795 // Peephole optimization
1796 if (matchRoot instanceof Slice) {
1797 root = BnM.optimize(matchRoot);
1798 if (root == matchRoot) {
1799 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1800 }
1801 } else if (matchRoot instanceof Begin || matchRoot instanceof First) {
1802 root = matchRoot;
1803 } else {
1804 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1805 }
1806
1807 // Optimize the greedy Loop to prevent exponential backtracking, IF there
1808 // is no group ref in this pattern. With a non-negative localTCNCount value,
1809 // the greedy type Loop, Curly will skip the backtracking for any starting
1810 // position "i" that failed in the past.
1811 if (!hasGroupRef) {
1812 for (Node node : topClosureNodes) {
1813 if (node instanceof Loop) {
1814 // non-deterministic-greedy-group
1815 ((Loop)node).posIndex = localTCNCount++;
1816 }
1817 }
1818 }
1819
1820 // Release temporary storage
1821 temp = null;
1822 buffer = null;
1823 groupNodes = null;
1824 patternLength = 0;
1825 compiled = true;
1826 topClosureNodes = null;
1827 }
1828
1829 Map<String, Integer> namedGroups() {
1830 Map<String, Integer> groups = namedGroups;
1831 if (groups == null) {
1832 namedGroups = groups = new HashMap<>(2);
1833 }
1834 return groups;
1835 }
1836
1837 /**
1838 * Used to accumulate information about a subtree of the object graph
1839 * so that optimizations can be applied to the subtree.
1840 */
1841 static final class TreeInfo {
1842 int minLength;
1843 int maxLength;
1844 boolean maxValid;
1845 boolean deterministic;
1846
1847 TreeInfo() {
1848 reset();
1849 }
1850 void reset() {
1851 minLength = 0;
1852 maxLength = 0;
1853 maxValid = true;
1854 deterministic = true;
1855 }
1856 }
1857
1858 /*
1859 * The following private methods are mainly used to improve the
1860 * readability of the code. In order to let the Java compiler easily
1861 * inline them, we should not put many assertions or error checks in them.
1862 */
1863
1864 /**
1865 * Indicates whether a particular flag is set or not.
1866 */
1867 private boolean has(int f) {
1868 return (flags0 & f) != 0;
1869 }
1870
1871 /**
1872 * Match next character, signal error if failed.
1873 */
1874 private void accept(int ch, String s) {
1875 int testChar = temp[cursor++];
1876 if (has(COMMENTS))
1877 testChar = parsePastWhitespace(testChar);
1878 if (ch != testChar) {
1879 throw error(s);
1880 }
1881 }
1882
1883 /**
1884 * Mark the end of pattern with a specific character.
1885 */
1886 private void mark(int c) {
1887 temp[patternLength] = c;
1888 }
1889
1890 /**
1891 * Peek the next character, and do not advance the cursor.
1892 */
1893 private int peek() {
1894 int ch = temp[cursor];
1895 if (has(COMMENTS))
1896 ch = peekPastWhitespace(ch);
1897 return ch;
1898 }
1899
1900 /**
1901 * Read the next character, and advance the cursor by one.
1902 */
1903 private int read() {
1904 int ch = temp[cursor++];
1905 if (has(COMMENTS))
1906 ch = parsePastWhitespace(ch);
1907 return ch;
1908 }
1909
1910 /**
1911 * Read the next character, and advance the cursor by one,
1912 * ignoring the COMMENTS setting
1913 */
1914 private int readEscaped() {
1915 int ch = temp[cursor++];
1916 return ch;
1917 }
1918
1919 /**
1920 * Advance the cursor by one, and peek the next character.
1921 */
1922 private int next() {
1923 int ch = temp[++cursor];
1924 if (has(COMMENTS))
1925 ch = peekPastWhitespace(ch);
1926 return ch;
1927 }
1928
1929 /**
1930 * Advance the cursor by one, and peek the next character,
1931 * ignoring the COMMENTS setting
1932 */
1933 private int nextEscaped() {
1934 int ch = temp[++cursor];
1935 return ch;
1936 }
1937
1938 /**
1939 * If in xmode peek past whitespace and comments.
1940 */
1941 private int peekPastWhitespace(int ch) {
1942 while (ASCII.isSpace(ch) || ch == '#') {
1943 while (ASCII.isSpace(ch))
1944 ch = temp[++cursor];
1945 if (ch == '#') {
1946 ch = peekPastLine();
1947 }
1948 }
1949 return ch;
1950 }
1951
1952 /**
1953 * If in xmode parse past whitespace and comments.
1954 */
1955 private int parsePastWhitespace(int ch) {
1956 while (ASCII.isSpace(ch) || ch == '#') {
1957 while (ASCII.isSpace(ch))
1958 ch = temp[cursor++];
1959 if (ch == '#')
1960 ch = parsePastLine();
1961 }
1962 return ch;
1963 }
1964
1965 /**
1966 * xmode parse past comment to end of line.
1967 */
1968 private int parsePastLine() {
1969 int ch = temp[cursor++];
1970 while (ch != 0 && !isLineSeparator(ch))
1971 ch = temp[cursor++];
1972 return ch;
1973 }
1974
1975 /**
1976 * xmode peek past comment to end of line.
1977 */
1978 private int peekPastLine() {
1979 int ch = temp[++cursor];
1980 while (ch != 0 && !isLineSeparator(ch))
1981 ch = temp[++cursor];
1982 return ch;
1983 }
1984
1985 /**
1986 * Determines if character is a line separator in the current mode
1987 */
1988 private boolean isLineSeparator(int ch) {
1989 if (has(UNIX_LINES)) {
1990 return ch == '\n';
1991 } else {
1992 return (ch == '\n' ||
1993 ch == '\r' ||
1994 (ch|1) == '\u2029' ||
1995 ch == '\u0085');
1996 }
1997 }
1998
1999 /**
2000 * Read the character after the next one, and advance the cursor by two.
2001 */
2002 private int skip() {
2003 int i = cursor;
2004 int ch = temp[i+1];
2005 cursor = i + 2;
2006 return ch;
2007 }
2008
2009 /**
2010 * Unread one next character, and retreat cursor by one.
2011 */
2012 private void unread() {
2013 cursor--;
2014 }
2015
2016 /**
2017 * Internal method used for handling all syntax errors. The pattern is
2018 * displayed with a pointer to aid in locating the syntax error.
2019 */
2020 private PatternSyntaxException error(String s) {
2021 return new PatternSyntaxException(s, normalizedPattern, cursor - 1);
2022 }
2023
2024 /**
2025 * Determines if there is any supplementary character or unpaired
2026 * surrogate in the specified range.
2027 */
2028 private boolean findSupplementary(int start, int end) {
2029 for (int i = start; i < end; i++) {
2030 if (isSupplementary(temp[i]))
2031 return true;
2032 }
2033 return false;
2034 }
2035
2036 /**
2037 * Determines if the specified code point is a supplementary
2038 * character or unpaired surrogate.
2039 */
2040 private static final boolean isSupplementary(int ch) {
2041 return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT ||
2042 Character.isSurrogate((char)ch);
2043 }
2044
2045 /**
2046 * The following methods handle the main parsing. They are sorted
2047 * according to their precedence order, the lowest one first.
2048 */
2049
2050 /**
2051 * The expression is parsed with branch nodes added for alternations.
2052 * This may be called recursively to parse sub expressions that may
2053 * contain alternations.
2054 */
2055 private Node expr(Node end) {
2056 Node prev = null;
2057 Node firstTail = null;
2058 Branch branch = null;
2059 Node branchConn = null;
2060
2061 for (;;) {
2062 Node node = sequence(end);
2063 Node nodeTail = root; //double return
2064 if (prev == null) {
2065 prev = node;
2066 firstTail = nodeTail;
2067 } else {
2068 // Branch
2069 if (branchConn == null) {
2070 branchConn = new BranchConn();
2071 branchConn.next = end;
2072 }
2073 if (node == end) {
2074 // if the node returned from sequence() is "end"
2075 // we have an empty expr, set a null atom into
2076 // the branch to indicate to go "next" directly.
2077 node = null;
2078 } else {
2079 // the "tail.next" of each atom goes to branchConn
2080 nodeTail.next = branchConn;
2081 }
2082 if (prev == branch) {
2083 branch.add(node);
2084 } else {
2085 if (prev == end) {
2086 prev = null;
2087 } else {
2088 // replace the "end" with "branchConn" at its tail.next
2089 // when put the "prev" into the branch as the first atom.
2090 firstTail.next = branchConn;
2091 }
2092 prev = branch = new Branch(prev, node, branchConn);
2093 }
2094 }
2095 if (peek() != '|') {
2096 return prev;
2097 }
2098 next();
2099 }
2100 }
2101
2102 @SuppressWarnings("fallthrough")
2103 /**
2104 * Parsing of sequences between alternations.
2105 */
2106 private Node sequence(Node end) {
2107 Node head = null;
2108 Node tail = null;
2109 Node node = null;
2110 LOOP:
2111 for (;;) {
2112 int ch = peek();
2113 switch (ch) {
2114 case '(':
2115 // Because group handles its own closure,
2116 // we need to treat it differently
2117 node = group0();
2118 // Check for comment or flag group
2119 if (node == null)
2120 continue;
2121 if (head == null)
2122 head = node;
2123 else
2124 tail.next = node;
2125 // Double return: Tail was returned in root
2126 tail = root;
2127 continue;
2128 case '[':
2129 if (has(CANON_EQ) && !has(LITERAL))
2130 node = new NFCCharProperty(clazz(true));
2131 else
2132 node = newCharProperty(clazz(true));
2133 break;
2134 case '\\':
2135 ch = nextEscaped();
2136 if (ch == 'p' || ch == 'P') {
2137 boolean oneLetter = true;
2138 boolean comp = (ch == 'P');
2139 ch = next(); // Consume { if present
2140 if (ch != '{') {
2141 unread();
2142 } else {
2143 oneLetter = false;
2144 }
2145 // node = newCharProperty(family(oneLetter, comp));
2146 if (has(CANON_EQ) && !has(LITERAL))
2147 node = new NFCCharProperty(family(oneLetter, comp));
2148 else
2149 node = newCharProperty(family(oneLetter, comp));
2150 } else {
2151 unread();
2152 node = atom();
2153 }
2154 break;
2155 case '^':
2156 next();
2157 if (has(MULTILINE)) {
2158 if (has(UNIX_LINES))
2159 node = new UnixCaret();
2160 else
2161 node = new Caret();
2162 } else {
2163 node = new Begin();
2164 }
2165 break;
2166 case '$':
2167 next();
2168 if (has(UNIX_LINES))
2169 node = new UnixDollar(has(MULTILINE));
2170 else
2171 node = new Dollar(has(MULTILINE));
2172 break;
2173 case '.':
2174 next();
2175 if (has(DOTALL)) {
2176 node = new CharProperty(ALL());
2177 } else {
2178 if (has(UNIX_LINES)) {
2179 node = new CharProperty(UNIXDOT());
2180 } else {
2181 node = new CharProperty(DOT());
2182 }
2183 }
2184 break;
2185 case '|':
2186 case ')':
2187 break LOOP;
2188 case ']': // Now interpreting dangling ] and } as literals
2189 case '}':
2190 node = atom();
2191 break;
2192 case '?':
2193 case '*':
2194 case '+':
2195 next();
2196 throw error("Dangling meta character '" + ((char)ch) + "'");
2197 case 0:
2198 if (cursor >= patternLength) {
2199 break LOOP;
2200 }
2201 // Fall through
2202 default:
2203 node = atom();
2204 break;
2205 }
2206
2207 node = closure(node);
2208 /* save the top dot-greedy nodes (.*, .+) as well
2209 if (node instanceof GreedyCharProperty &&
2210 ((GreedyCharProperty)node).cp instanceof Dot) {
2211 topClosureNodes.add(node);
2212 }
2213 */
2214 if (head == null) {
2215 head = tail = node;
2216 } else {
2217 tail.next = node;
2218 tail = node;
2219 }
2220 }
2221 if (head == null) {
2222 return end;
2223 }
2224 tail.next = end;
2225 root = tail; //double return
2226 return head;
2227 }
2228
2229 @SuppressWarnings("fallthrough")
2230 /**
2231 * Parse and add a new Single or Slice.
2232 */
2233 private Node atom() {
2234 int first = 0;
2235 int prev = -1;
2236 boolean hasSupplementary = false;
2237 int ch = peek();
2238 for (;;) {
2239 switch (ch) {
2240 case '*':
2241 case '+':
2242 case '?':
2243 case '{':
2244 if (first > 1) {
2245 cursor = prev; // Unwind one character
2246 first--;
2247 }
2248 break;
2249 case '$':
2250 case '.':
2251 case '^':
2252 case '(':
2253 case '[':
2254 case '|':
2255 case ')':
2256 break;
2257 case '\\':
2258 ch = nextEscaped();
2259 if (ch == 'p' || ch == 'P') { // Property
2260 if (first > 0) { // Slice is waiting; handle it first
2261 unread();
2262 break;
2263 } else { // No slice; just return the family node
2264 boolean comp = (ch == 'P');
2265 boolean oneLetter = true;
2266 ch = next(); // Consume { if present
2267 if (ch != '{')
2268 unread();
2269 else
2270 oneLetter = false;
2271 if (has(CANON_EQ) && !has(LITERAL))
2272 return new NFCCharProperty(family(oneLetter, comp));
2273 else
2274 return newCharProperty(family(oneLetter, comp));
2275 }
2276 }
2277 unread();
2278 prev = cursor;
2279 ch = escape(false, first == 0, false);
2280 if (ch >= 0) {
2281 append(ch, first);
2282 first++;
2283 if (isSupplementary(ch)) {
2284 hasSupplementary = true;
2285 }
2286 ch = peek();
2287 continue;
2288 } else if (first == 0) {
2289 return root;
2290 }
2291 // Unwind meta escape sequence
2292 cursor = prev;
2293 break;
2294 case 0:
2295 if (cursor >= patternLength) {
2296 break;
2297 }
2298 // Fall through
2299 default:
2300 prev = cursor;
2301 append(ch, first);
2302 first++;
2303 if (isSupplementary(ch)) {
2304 hasSupplementary = true;
2305 }
2306 ch = next();
2307 continue;
2308 }
2309 break;
2310 }
2311 if (first == 1) {
2312 return newCharProperty(single(buffer[0]));
2313 } else {
2314 return newSlice(buffer, first, hasSupplementary);
2315 }
2316 }
2317
2318 private void append(int ch, int len) {
2319 if (len >= buffer.length) {
2320 int[] tmp = new int[len+len];
2321 System.arraycopy(buffer, 0, tmp, 0, len);
2322 buffer = tmp;
2323 }
2324 buffer[len] = ch;
2325 }
2326
2327 /**
2328 * Parses a backref greedily, taking as many numbers as it
2329 * can. The first digit is always treated as a backref, but
2330 * multi digit numbers are only treated as a backref if at
2331 * least that many backrefs exist at this point in the regex.
2332 */
2333 private Node ref(int refNum) {
2334 boolean done = false;
2335 while(!done) {
2336 int ch = peek();
2337 switch(ch) {
2338 case '0':
2339 case '1':
2340 case '2':
2341 case '3':
2342 case '4':
2343 case '5':
2344 case '6':
2345 case '7':
2346 case '8':
2347 case '9':
2348 int newRefNum = (refNum * 10) + (ch - '0');
2349 // Add another number if it doesn't make a group
2350 // that doesn't exist
2351 if (capturingGroupCount - 1 < newRefNum) {
2352 done = true;
2353 break;
2354 }
2355 refNum = newRefNum;
2356 read();
2357 break;
2358 default:
2359 done = true;
2360 break;
2361 }
2362 }
2363 hasGroupRef = true;
2364 if (has(CASE_INSENSITIVE))
2365 return new CIBackRef(refNum, has(UNICODE_CASE));
2366 else
2367 return new BackRef(refNum);
2368 }
2369
2370 /**
2371 * Parses an escape sequence to determine the actual value that needs
2372 * to be matched.
2373 * If -1 is returned and create was true a new object was added to the tree
2374 * to handle the escape sequence.
2375 * If the returned value is greater than zero, it is the value that
2376 * matches the escape sequence.
2377 */
2378 private int escape(boolean inclass, boolean create, boolean isrange) {
2379 int ch = skip();
2380 switch (ch) {
2381 case '0':
2382 return o();
2383 case '1':
2384 case '2':
2385 case '3':
2386 case '4':
2387 case '5':
2388 case '6':
2389 case '7':
2390 case '8':
2391 case '9':
2392 if (inclass) break;
2393 if (create) {
2394 root = ref((ch - '0'));
2395 }
2396 return -1;
2397 case 'A':
2398 if (inclass) break;
2399 if (create) root = new Begin();
2400 return -1;
2401 case 'B':
2402 if (inclass) break;
2403 if (create) root = new Bound(Bound.NONE, has(UNICODE_CHARACTER_CLASS));
2404 return -1;
2405 case 'C':
2406 break;
2407 case 'D':
2408 if (create) {
2409 predicate = has(UNICODE_CHARACTER_CLASS) ?
2410 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2411 predicate = predicate.negate();
2412 if (!inclass)
2413 root = newCharProperty(predicate);
2414 }
2415 return -1;
2416 case 'E':
2417 case 'F':
2418 break;
2419 case 'G':
2420 if (inclass) break;
2421 if (create) root = new LastMatch();
2422 return -1;
2423 case 'H':
2424 if (create) {
2425 predicate = HorizWS().negate();
2426 if (!inclass)
2427 root = newCharProperty(predicate);
2428 }
2429 return -1;
2430 case 'I':
2431 case 'J':
2432 case 'K':
2433 case 'L':
2434 case 'M':
2435 break;
2436 case 'N':
2437 return N();
2438 case 'O':
2439 case 'P':
2440 case 'Q':
2441 break;
2442 case 'R':
2443 if (inclass) break;
2444 if (create) root = new LineEnding();
2445 return -1;
2446 case 'S':
2447 if (create) {
2448 predicate = has(UNICODE_CHARACTER_CLASS) ?
2449 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2450 predicate = predicate.negate();
2451 if (!inclass)
2452 root = newCharProperty(predicate);
2453 }
2454 return -1;
2455 case 'T':
2456 case 'U':
2457 break;
2458 case 'V':
2459 if (create) {
2460 predicate = VertWS().negate();
2461 if (!inclass)
2462 root = newCharProperty(predicate);
2463 }
2464 return -1;
2465 case 'W':
2466 if (create) {
2467 predicate = has(UNICODE_CHARACTER_CLASS) ?
2468 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2469 predicate = predicate.negate();
2470 if (!inclass)
2471 root = newCharProperty(predicate);
2472 }
2473 return -1;
2474 case 'X':
2475 if (inclass) break;
2476 if (create) {
2477 root = new XGrapheme();
2478 }
2479 return -1;
2480 case 'Y':
2481 break;
2482 case 'Z':
2483 if (inclass) break;
2484 if (create) {
2485 if (has(UNIX_LINES))
2486 root = new UnixDollar(false);
2487 else
2488 root = new Dollar(false);
2489 }
2490 return -1;
2491 case 'a':
2492 return '\007';
2493 case 'b':
2494 if (inclass) break;
2495 if (create) {
2496 if (peek() == '{') {
2497 if (skip() == 'g') {
2498 if (read() == '}') {
2499 root = new GraphemeBound();
2500 return -1;
2501 }
2502 break; // error missing trailing }
2503 }
2504 unread(); unread();
2505 }
2506 root = new Bound(Bound.BOTH, has(UNICODE_CHARACTER_CLASS));
2507 }
2508 return -1;
2509 case 'c':
2510 return c();
2511 case 'd':
2512 if (create) {
2513 predicate = has(UNICODE_CHARACTER_CLASS) ?
2514 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2515 if (!inclass)
2516 root = newCharProperty(predicate);
2517 }
2518 return -1;
2519 case 'e':
2520 return '\033';
2521 case 'f':
2522 return '\f';
2523 case 'g':
2524 break;
2525 case 'h':
2526 if (create) {
2527 predicate = HorizWS();
2528 if (!inclass)
2529 root = newCharProperty(predicate);
2530 }
2531 return -1;
2532 case 'i':
2533 case 'j':
2534 break;
2535 case 'k':
2536 if (inclass)
2537 break;
2538 if (read() != '<')
2539 throw error("\\k is not followed by '<' for named capturing group");
2540 String name = groupname(read());
2541 if (!namedGroups().containsKey(name))
2542 throw error("named capturing group <" + name + "> does not exist");
2543 if (create) {
2544 hasGroupRef = true;
2545 if (has(CASE_INSENSITIVE))
2546 root = new CIBackRef(namedGroups().get(name), has(UNICODE_CASE));
2547 else
2548 root = new BackRef(namedGroups().get(name));
2549 }
2550 return -1;
2551 case 'l':
2552 case 'm':
2553 break;
2554 case 'n':
2555 return '\n';
2556 case 'o':
2557 case 'p':
2558 case 'q':
2559 break;
2560 case 'r':
2561 return '\r';
2562 case 's':
2563 if (create) {
2564 predicate = has(UNICODE_CHARACTER_CLASS) ?
2565 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2566 if (!inclass)
2567 root = newCharProperty(predicate);
2568 }
2569 return -1;
2570 case 't':
2571 return '\t';
2572 case 'u':
2573 return u();
2574 case 'v':
2575 // '\v' was implemented as VT/0x0B in releases < 1.8 (though
2576 // undocumented). In JDK8 '\v' is specified as a predefined
2577 // character class for all vertical whitespace characters.
2578 // So [-1, root=VertWS node] pair is returned (instead of a
2579 // single 0x0B). This breaks the range if '\v' is used as
2580 // the start or end value, such as [\v-...] or [...-\v], in
2581 // which a single definite value (0x0B) is expected. For
2582 // compatibility concern '\013'/0x0B is returned if isrange.
2583 if (isrange)
2584 return '\013';
2585 if (create) {
2586 predicate = VertWS();
2587 if (!inclass)
2588 root = newCharProperty(predicate);
2589 }
2590 return -1;
2591 case 'w':
2592 if (create) {
2593 predicate = has(UNICODE_CHARACTER_CLASS) ?
2594 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2595 if (!inclass)
2596 root = newCharProperty(predicate);
2597 }
2598 return -1;
2599 case 'x':
2600 return x();
2601 case 'y':
2602 break;
2603 case 'z':
2604 if (inclass) break;
2605 if (create) root = new End();
2606 return -1;
2607 default:
2608 return ch;
2609 }
2610 throw error("Illegal/unsupported escape sequence");
2611 }
2612
2613 /**
2614 * Parse a character class, and return the node that matches it.
2615 *
2616 * Consumes a ] on the way out if consume is true. Usually consume
2617 * is true except for the case of [abc&&def] where def is a separate
2618 * right hand node with "understood" brackets.
2619 */
2620 private CharPredicate clazz(boolean consume) {
2621 CharPredicate prev = null;
2622 CharPredicate curr = null;
2623 BitClass bits = new BitClass();
2624 BmpCharPredicate bitsP = ch -> ch < 256 && bits.bits[ch];
2625
2626 boolean isNeg = false;
2627 boolean hasBits = false;
2628 int ch = next();
2629
2630 // Negates if first char in a class, otherwise literal
2631 if (ch == '^' && temp[cursor-1] == '[') {
2632 ch = next();
2633 isNeg = true;
2634 }
2635 for (;;) {
2636 switch (ch) {
2637 case '[':
2638 curr = clazz(true);
2639 if (prev == null)
2640 prev = curr;
2641 else
2642 prev = prev.union(curr);
2643 ch = peek();
2644 continue;
2645 case '&':
2646 ch = next();
2647 if (ch == '&') {
2648 ch = next();
2649 CharPredicate right = null;
2650 while (ch != ']' && ch != '&') {
2651 if (ch == '[') {
2652 if (right == null)
2653 right = clazz(true);
2654 else
2655 right = right.union(clazz(true));
2656 } else { // abc&&def
2657 unread();
2658 right = clazz(false);
2659 }
2660 ch = peek();
2661 }
2662 if (hasBits) {
2663 // bits used, union has high precedence
2664 if (prev == null) {
2665 prev = curr = bitsP;
2666 } else {
2667 prev = prev.union(bitsP);
2668 }
2669 hasBits = false;
2670 }
2671 if (right != null)
2672 curr = right;
2673 if (prev == null) {
2674 if (right == null)
2675 throw error("Bad class syntax");
2676 else
2677 prev = right;
2678 } else {
2679 prev = prev.and(curr);
2680 }
2681 } else {
2682 // treat as a literal &
2683 unread();
2684 break;
2685 }
2686 continue;
2687 case 0:
2688 if (cursor >= patternLength)
2689 throw error("Unclosed character class");
2690 break;
2691 case ']':
2692 if (prev != null || hasBits) {
2693 if (consume)
2694 next();
2695 if (prev == null)
2696 prev = bitsP;
2697 else if (hasBits)
2698 prev = prev.union(bitsP);
2699 if (isNeg)
2700 return prev.negate();
2701 return prev;
2702 }
2703 break;
2704 default:
2705 break;
2706 }
2707 curr = range(bits);
2708 if (curr == null) { // the bits used
2709 hasBits = true;
2710 } else {
2711 if (prev == null)
2712 prev = curr;
2713 else if (prev != curr)
2714 prev = prev.union(curr);
2715 }
2716 ch = peek();
2717 }
2718 }
2719
2720 private CharPredicate bitsOrSingle(BitClass bits, int ch) {
2721 /* Bits can only handle codepoints in [u+0000-u+00ff] range.
2722 Use "single" node instead of bits when dealing with unicode
2723 case folding for codepoints listed below.
2724 (1)Uppercase out of range: u+00ff, u+00b5
2725 toUpperCase(u+00ff) -> u+0178
2726 toUpperCase(u+00b5) -> u+039c
2727 (2)LatinSmallLetterLongS u+17f
2728 toUpperCase(u+017f) -> u+0053
2729 (3)LatinSmallLetterDotlessI u+131
2730 toUpperCase(u+0131) -> u+0049
2731 (4)LatinCapitalLetterIWithDotAbove u+0130
2732 toLowerCase(u+0130) -> u+0069
2733 (5)KelvinSign u+212a
2734 toLowerCase(u+212a) ==> u+006B
2735 (6)AngstromSign u+212b
2736 toLowerCase(u+212b) ==> u+00e5
2737 */
2738 if (ch < 256 &&
2739 !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) &&
2740 (ch == 0xff || ch == 0xb5 ||
2741 ch == 0x49 || ch == 0x69 || //I and i
2742 ch == 0x53 || ch == 0x73 || //S and s
2743 ch == 0x4b || ch == 0x6b || //K and k
2744 ch == 0xc5 || ch == 0xe5))) { //A+ring
2745 bits.add(ch, flags0);
2746 return null;
2747 }
2748 return single(ch);
2749 }
2750
2751 /**
2752 * Returns a suitably optimized, single character predicate
2753 */
2754 private CharPredicate single(final int ch) {
2755 if (has(CASE_INSENSITIVE)) {
2756 int lower, upper;
2757 if (has(UNICODE_CASE)) {
2758 upper = Character.toUpperCase(ch);
2759 lower = Character.toLowerCase(upper);
2760 // Unicode case insensitive matches
2761 if (upper != lower)
2762 return SingleU(lower);
2763 } else if (ASCII.isAscii(ch)) {
2764 lower = ASCII.toLower(ch);
2765 upper = ASCII.toUpper(ch);
2766 // Case insensitive matches a given BMP character
2767 if (lower != upper)
2768 return SingleI(lower, upper);
2769 }
2770 }
2771 if (isSupplementary(ch))
2772 return SingleS(ch);
2773 return Single(ch); // Match a given BMP character
2774 }
2775
2776 /**
2777 * Parse a single character or a character range in a character class
2778 * and return its representative node.
2779 */
2780 private CharPredicate range(BitClass bits) {
2781 int ch = peek();
2782 if (ch == '\\') {
2783 ch = nextEscaped();
2784 if (ch == 'p' || ch == 'P') { // A property
2785 boolean comp = (ch == 'P');
2786 boolean oneLetter = true;
2787 // Consume { if present
2788 ch = next();
2789 if (ch != '{')
2790 unread();
2791 else
2792 oneLetter = false;
2793 return family(oneLetter, comp);
2794 } else { // ordinary escape
2795 boolean isrange = temp[cursor+1] == '-';
2796 unread();
2797 ch = escape(true, true, isrange);
2798 if (ch == -1)
2799 return predicate;
2800 }
2801 } else {
2802 next();
2803 }
2804 if (ch >= 0) {
2805 if (peek() == '-') {
2806 int endRange = temp[cursor+1];
2807 if (endRange == '[') {
2808 return bitsOrSingle(bits, ch);
2809 }
2810 if (endRange != ']') {
2811 next();
2812 int m = peek();
2813 if (m == '\\') {
2814 m = escape(true, false, true);
2815 } else {
2816 next();
2817 }
2818 if (m < ch) {
2819 throw error("Illegal character range");
2820 }
2821 if (has(CASE_INSENSITIVE)) {
2822 if (has(UNICODE_CASE))
2823 return CIRangeU(ch, m);
2824 return CIRange(ch, m);
2825 } else {
2826 return Range(ch, m);
2827 }
2828 }
2829 }
2830 return bitsOrSingle(bits, ch);
2831 }
2832 throw error("Unexpected character '"+((char)ch)+"'");
2833 }
2834
2835 /**
2836 * Parses a Unicode character family and returns its representative node.
2837 */
2838 private CharPredicate family(boolean singleLetter, boolean isComplement) {
2839 next();
2840 String name;
2841 CharPredicate p = null;
2842
2843 if (singleLetter) {
2844 int c = temp[cursor];
2845 if (!Character.isSupplementaryCodePoint(c)) {
2846 name = String.valueOf((char)c);
2847 } else {
2848 name = new String(temp, cursor, 1);
2849 }
2850 read();
2851 } else {
2852 int i = cursor;
2853 mark('}');
2854 while(read() != '}') {
2855 }
2856 mark('\000');
2857 int j = cursor;
2858 if (j > patternLength)
2859 throw error("Unclosed character family");
2860 if (i + 1 >= j)
2861 throw error("Empty character family");
2862 name = new String(temp, i, j-i-1);
2863 }
2864
2865 int i = name.indexOf('=');
2866 if (i != -1) {
2867 // property construct \p{name=value}
2868 String value = name.substring(i + 1);
2869 name = name.substring(0, i).toLowerCase(Locale.ENGLISH);
2870 switch (name) {
2871 case "sc":
2872 case "script":
2873 p = CharPredicates.forUnicodeScript(value);
2874 break;
2875 case "blk":
2876 case "block":
2877 p = CharPredicates.forUnicodeBlock(value);
2878 break;
2879 case "gc":
2880 case "general_category":
2881 p = CharPredicates.forProperty(value);
2882 break;
2883 default:
2884 break;
2885 }
2886 if (p == null)
2887 throw error("Unknown Unicode property {name=<" + name + ">, "
2888 + "value=<" + value + ">}");
2889
2890 } else {
2891 if (name.startsWith("In")) {
2892 // \p{InBlockName}
2893 p = CharPredicates.forUnicodeBlock(name.substring(2));
2894 } else if (name.startsWith("Is")) {
2895 // \p{IsGeneralCategory} and \p{IsScriptName}
2896 name = name.substring(2);
2897 p = CharPredicates.forUnicodeProperty(name);
2898 if (p == null)
2899 p = CharPredicates.forProperty(name);
2900 if (p == null)
2901 p = CharPredicates.forUnicodeScript(name);
2902 } else {
2903 if (has(UNICODE_CHARACTER_CLASS)) {
2904 p = CharPredicates.forPOSIXName(name);
2905 }
2906 if (p == null)
2907 p = CharPredicates.forProperty(name);
2908 }
2909 if (p == null)
2910 throw error("Unknown character property name {In/Is" + name + "}");
2911 }
2912 if (isComplement) {
2913 // it might be too expensive to detect if a complement of
2914 // CharProperty can match "certain" supplementary. So just
2915 // go with StartS.
2916 hasSupplementary = true;
2917 p = p.negate();
2918 }
2919 return p;
2920 }
2921
2922 private CharProperty newCharProperty(CharPredicate p) {
2923 if (p == null)
2924 return null;
2925 if (p instanceof BmpCharPredicate)
2926 return new BmpCharProperty((BmpCharPredicate)p);
2927 else
2928 return new CharProperty(p);
2929 }
2930
2931 /**
2932 * Parses and returns the name of a "named capturing group", the trailing
2933 * ">" is consumed after parsing.
2934 */
2935 private String groupname(int ch) {
2936 StringBuilder sb = new StringBuilder();
2937 if (!ASCII.isAlpha(ch))
2938 throw error("capturing group name does not start with a Latin letter");
2939 do {
2940 sb.append((char) ch);
2941 } while (ASCII.isAlnum(ch=read()));
2942 if (ch != '>')
2943 throw error("named capturing group is missing trailing '>'");
2944 return sb.toString();
2945 }
2946
2947 /**
2948 * Parses a group and returns the head node of a set of nodes that process
2949 * the group. Sometimes a double return system is used where the tail is
2950 * returned in root.
2951 */
2952 private Node group0() {
2953 boolean capturingGroup = false;
2954 Node head = null;
2955 Node tail = null;
2956 int save = flags0;
2957 int saveTCNCount = topClosureNodes.size();
2958 root = null;
2959 int ch = next();
2960 if (ch == '?') {
2961 ch = skip();
2962 switch (ch) {
2963 case ':': // (?:xxx) pure group
2964 head = createGroup(true);
2965 tail = root;
2966 head.next = expr(tail);
2967 break;
2968 case '=': // (?=xxx) and (?!xxx) lookahead
2969 case '!':
2970 head = createGroup(true);
2971 tail = root;
2972 head.next = expr(tail);
2973 if (ch == '=') {
2974 head = tail = new Pos(head);
2975 } else {
2976 head = tail = new Neg(head);
2977 }
2978 break;
2979 case '>': // (?>xxx) independent group
2980 head = createGroup(true);
2981 tail = root;
2982 head.next = expr(tail);
2983 head = tail = new Ques(head, Qtype.INDEPENDENT);
2984 break;
2985 case '<': // (?<xxx) look behind
2986 ch = read();
2987 if (ch != '=' && ch != '!') {
2988 // named captured group
2989 String name = groupname(ch);
2990 if (namedGroups().containsKey(name))
2991 throw error("Named capturing group <" + name
2992 + "> is already defined");
2993 capturingGroup = true;
2994 head = createGroup(false);
2995 tail = root;
2996 namedGroups().put(name, capturingGroupCount-1);
2997 head.next = expr(tail);
2998 break;
2999 }
3000 int start = cursor;
3001 head = createGroup(true);
3002 tail = root;
3003 head.next = expr(tail);
3004 tail.next = lookbehindEnd;
3005 TreeInfo info = new TreeInfo();
3006 head.study(info);
3007 if (info.maxValid == false) {
3008 throw error("Look-behind group does not have "
3009 + "an obvious maximum length");
3010 }
3011 boolean hasSupplementary = findSupplementary(start, patternLength);
3012 if (ch == '=') {
3013 head = tail = (hasSupplementary ?
3014 new BehindS(head, info.maxLength,
3015 info.minLength) :
3016 new Behind(head, info.maxLength,
3017 info.minLength));
3018 } else { // if (ch == '!')
3019 head = tail = (hasSupplementary ?
3020 new NotBehindS(head, info.maxLength,
3021 info.minLength) :
3022 new NotBehind(head, info.maxLength,
3023 info.minLength));
3024 }
3025 // clear all top-closure-nodes inside lookbehind
3026 if (saveTCNCount < topClosureNodes.size())
3027 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3028 break;
3029 case '$':
3030 case '@':
3031 throw error("Unknown group type");
3032 default: // (?xxx:) inlined match flags
3033 unread();
3034 addFlag();
3035 ch = read();
3036 if (ch == ')') {
3037 return null; // Inline modifier only
3038 }
3039 if (ch != ':') {
3040 throw error("Unknown inline modifier");
3041 }
3042 head = createGroup(true);
3043 tail = root;
3044 head.next = expr(tail);
3045 break;
3046 }
3047 } else { // (xxx) a regular group
3048 capturingGroup = true;
3049 head = createGroup(false);
3050 tail = root;
3051 head.next = expr(tail);
3052 }
3053
3054 accept(')', "Unclosed group");
3055 flags0 = save;
3056
3057 // Check for quantifiers
3058 Node node = closure(head);
3059 if (node == head) { // No closure
3060 root = tail;
3061 return node; // Dual return
3062 }
3063 if (head == tail) { // Zero length assertion
3064 root = node;
3065 return node; // Dual return
3066 }
3067
3068 // have group closure, clear all inner closure nodes from the
3069 // top list (no backtracking stopper optimization for inner
3070 if (saveTCNCount < topClosureNodes.size())
3071 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3072
3073 if (node instanceof Ques) {
3074 Ques ques = (Ques) node;
3075 if (ques.type == Qtype.POSSESSIVE) {
3076 root = node;
3077 return node;
3078 }
3079 tail.next = new BranchConn();
3080 tail = tail.next;
3081 if (ques.type == Qtype.GREEDY) {
3082 head = new Branch(head, null, tail);
3083 } else { // Reluctant quantifier
3084 head = new Branch(null, head, tail);
3085 }
3086 root = tail;
3087 return head;
3088 } else if (node instanceof Curly) {
3089 Curly curly = (Curly) node;
3090 if (curly.type == Qtype.POSSESSIVE) {
3091 root = node;
3092 return node;
3093 }
3094 // Discover if the group is deterministic
3095 TreeInfo info = new TreeInfo();
3096 if (head.study(info)) { // Deterministic
3097 GroupTail temp = (GroupTail) tail;
3098 head = root = new GroupCurly(head.next, curly.cmin,
3099 curly.cmax, curly.type,
3100 ((GroupTail)tail).localIndex,
3101 ((GroupTail)tail).groupIndex,
3102 capturingGroup);
3103 return head;
3104 } else { // Non-deterministic
3105 int temp = ((GroupHead) head).localIndex;
3106 Loop loop;
3107 if (curly.type == Qtype.GREEDY) {
3108 loop = new Loop(this.localCount, temp);
3109 // add the max_reps greedy to the top-closure-node list
3110 if (curly.cmax == MAX_REPS)
3111 topClosureNodes.add(loop);
3112 } else { // Reluctant Curly
3113 loop = new LazyLoop(this.localCount, temp);
3114 }
3115 Prolog prolog = new Prolog(loop);
3116 this.localCount += 1;
3117 loop.cmin = curly.cmin;
3118 loop.cmax = curly.cmax;
3119 loop.body = head;
3120 tail.next = loop;
3121 root = loop;
3122 return prolog; // Dual return
3123 }
3124 }
3125 throw error("Internal logic error");
3126 }
3127
3128 /**
3129 * Create group head and tail nodes using double return. If the group is
3130 * created with anonymous true then it is a pure group and should not
3131 * affect group counting.
3132 */
3133 private Node createGroup(boolean anonymous) {
3134 int localIndex = localCount++;
3135 int groupIndex = 0;
3136 if (!anonymous)
3137 groupIndex = capturingGroupCount++;
3138 GroupHead head = new GroupHead(localIndex);
3139 root = new GroupTail(localIndex, groupIndex);
3140
3141 // for debug/print only, head.match does NOT need the "tail" info
3142 head.tail = (GroupTail)root;
3143
3144 if (!anonymous && groupIndex < 10)
3145 groupNodes[groupIndex] = head;
3146 return head;
3147 }
3148
3149 @SuppressWarnings("fallthrough")
3150 /**
3151 * Parses inlined match flags and set them appropriately.
3152 */
3153 private void addFlag() {
3154 int ch = peek();
3155 for (;;) {
3156 switch (ch) {
3157 case 'i':
3158 flags0 |= CASE_INSENSITIVE;
3159 break;
3160 case 'm':
3161 flags0 |= MULTILINE;
3162 break;
3163 case 's':
3164 flags0 |= DOTALL;
3165 break;
3166 case 'd':
3167 flags0 |= UNIX_LINES;
3168 break;
3169 case 'u':
3170 flags0 |= UNICODE_CASE;
3171 break;
3172 case 'c':
3173 flags0 |= CANON_EQ;
3174 break;
3175 case 'x':
3176 flags0 |= COMMENTS;
3177 break;
3178 case 'U':
3179 flags0 |= (UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3180 break;
3181 case '-': // subFlag then fall through
3182 ch = next();
3183 subFlag();
3184 default:
3185 return;
3186 }
3187 ch = next();
3188 }
3189 }
3190
3191 @SuppressWarnings("fallthrough")
3192 /**
3193 * Parses the second part of inlined match flags and turns off
3194 * flags appropriately.
3195 */
3196 private void subFlag() {
3197 int ch = peek();
3198 for (;;) {
3199 switch (ch) {
3200 case 'i':
3201 flags0 &= ~CASE_INSENSITIVE;
3202 break;
3203 case 'm':
3204 flags0 &= ~MULTILINE;
3205 break;
3206 case 's':
3207 flags0 &= ~DOTALL;
3208 break;
3209 case 'd':
3210 flags0 &= ~UNIX_LINES;
3211 break;
3212 case 'u':
3213 flags0 &= ~UNICODE_CASE;
3214 break;
3215 case 'c':
3216 flags0 &= ~CANON_EQ;
3217 break;
3218 case 'x':
3219 flags0 &= ~COMMENTS;
3220 break;
3221 case 'U':
3222 flags0 &= ~(UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3223 break;
3224 default:
3225 return;
3226 }
3227 ch = next();
3228 }
3229 }
3230
3231 static final int MAX_REPS = 0x7FFFFFFF;
3232
3233 static enum Qtype {
3234 GREEDY, LAZY, POSSESSIVE, INDEPENDENT
3235 }
3236
3237 private Node curly(Node prev, int cmin) {
3238 int ch = next();
3239 if (ch == '?') {
3240 next();
3241 return new Curly(prev, cmin, MAX_REPS, Qtype.LAZY);
3242 } else if (ch == '+') {
3243 next();
3244 return new Curly(prev, cmin, MAX_REPS, Qtype.POSSESSIVE);
3245 }
3246 if (prev instanceof BmpCharProperty) {
3247 return new BmpCharPropertyGreedy((BmpCharProperty)prev, cmin);
3248 } else if (prev instanceof CharProperty) {
3249 return new CharPropertyGreedy((CharProperty)prev, cmin);
3250 }
3251 return new Curly(prev, cmin, MAX_REPS, Qtype.GREEDY);
3252 }
3253
3254 /**
3255 * Processes repetition. If the next character peeked is a quantifier
3256 * then new nodes must be appended to handle the repetition.
3257 * Prev could be a single or a group, so it could be a chain of nodes.
3258 */
3259 private Node closure(Node prev) {
3260 Node atom;
3261 int ch = peek();
3262 switch (ch) {
3263 case '?':
3264 ch = next();
3265 if (ch == '?') {
3266 next();
3267 return new Ques(prev, Qtype.LAZY);
3268 } else if (ch == '+') {
3269 next();
3270 return new Ques(prev, Qtype.POSSESSIVE);
3271 }
3272 return new Ques(prev, Qtype.GREEDY);
3273 case '*':
3274 return curly(prev, 0);
3275 case '+':
3276 return curly(prev, 1);
3277 case '{':
3278 ch = temp[cursor+1];
3279 if (ASCII.isDigit(ch)) {
3280 skip();
3281 int cmin = 0;
3282 do {
3283 cmin = cmin * 10 + (ch - '0');
3284 } while (ASCII.isDigit(ch = read()));
3285 int cmax = cmin;
3286 if (ch == ',') {
3287 ch = read();
3288 cmax = MAX_REPS;
3289 if (ch != '}') {
3290 cmax = 0;
3291 while (ASCII.isDigit(ch)) {
3292 cmax = cmax * 10 + (ch - '0');
3293 ch = read();
3294 }
3295 }
3296 }
3297 if (ch != '}')
3298 throw error("Unclosed counted closure");
3299 if (((cmin) | (cmax) | (cmax - cmin)) < 0)
3300 throw error("Illegal repetition range");
3301 Curly curly;
3302 ch = peek();
3303 if (ch == '?') {
3304 next();
3305 curly = new Curly(prev, cmin, cmax, Qtype.LAZY);
3306 } else if (ch == '+') {
3307 next();
3308 curly = new Curly(prev, cmin, cmax, Qtype.POSSESSIVE);
3309 } else {
3310 curly = new Curly(prev, cmin, cmax, Qtype.GREEDY);
3311 }
3312 return curly;
3313 } else {
3314 throw error("Illegal repetition");
3315 }
3316 default:
3317 return prev;
3318 }
3319 }
3320
3321 /**
3322 * Utility method for parsing control escape sequences.
3323 */
3324 private int c() {
3325 if (cursor < patternLength) {
3326 return read() ^ 64;
3327 }
3328 throw error("Illegal control escape sequence");
3329 }
3330
3331 /**
3332 * Utility method for parsing octal escape sequences.
3333 */
3334 private int o() {
3335 int n = read();
3336 if (((n-'0')|('7'-n)) >= 0) {
3337 int m = read();
3338 if (((m-'0')|('7'-m)) >= 0) {
3339 int o = read();
3340 if ((((o-'0')|('7'-o)) >= 0) && (((n-'0')|('3'-n)) >= 0)) {
3341 return (n - '0') * 64 + (m - '0') * 8 + (o - '0');
3342 }
3343 unread();
3344 return (n - '0') * 8 + (m - '0');
3345 }
3346 unread();
3347 return (n - '0');
3348 }
3349 throw error("Illegal octal escape sequence");
3350 }
3351
3352 /**
3353 * Utility method for parsing hexadecimal escape sequences.
3354 */
3355 private int x() {
3356 int n = read();
3357 if (ASCII.isHexDigit(n)) {
3358 int m = read();
3359 if (ASCII.isHexDigit(m)) {
3360 return ASCII.toDigit(n) * 16 + ASCII.toDigit(m);
3361 }
3362 } else if (n == '{' && ASCII.isHexDigit(peek())) {
3363 int ch = 0;
3364 while (ASCII.isHexDigit(n = read())) {
3365 ch = (ch << 4) + ASCII.toDigit(n);
3366 if (ch > Character.MAX_CODE_POINT)
3367 throw error("Hexadecimal codepoint is too big");
3368 }
3369 if (n != '}')
3370 throw error("Unclosed hexadecimal escape sequence");
3371 return ch;
3372 }
3373 throw error("Illegal hexadecimal escape sequence");
3374 }
3375
3376 /**
3377 * Utility method for parsing unicode escape sequences.
3378 */
3379 private int cursor() {
3380 return cursor;
3381 }
3382
3383 private void setcursor(int pos) {
3384 cursor = pos;
3385 }
3386
3387 private int uxxxx() {
3388 int n = 0;
3389 for (int i = 0; i < 4; i++) {
3390 int ch = read();
3391 if (!ASCII.isHexDigit(ch)) {
3392 throw error("Illegal Unicode escape sequence");
3393 }
3394 n = n * 16 + ASCII.toDigit(ch);
3395 }
3396 return n;
3397 }
3398
3399 private int u() {
3400 int n = uxxxx();
3401 if (Character.isHighSurrogate((char)n)) {
3402 int cur = cursor();
3403 if (read() == '\\' && read() == 'u') {
3404 int n2 = uxxxx();
3405 if (Character.isLowSurrogate((char)n2))
3406 return Character.toCodePoint((char)n, (char)n2);
3407 }
3408 setcursor(cur);
3409 }
3410 return n;
3411 }
3412
3413 private int N() {
3414 if (read() == '{') {
3415 int i = cursor;
3416 while (cursor < patternLength && read() != '}') {}
3417 if (cursor > patternLength)
3418 throw error("Unclosed character name escape sequence");
3419 String name = new String(temp, i, cursor - i - 1);
3420 try {
3421 return Character.codePointOf(name);
3422 } catch (IllegalArgumentException x) {
3423 throw error("Unknown character name [" + name + "]");
3424 }
3425 }
3426 throw error("Illegal character name escape sequence");
3427 }
3428
3429 //
3430 // Utility methods for code point support
3431 //
3432 private static final int countChars(CharSequence seq, int index,
3433 int lengthInCodePoints) {
3434 // optimization
3435 if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) {
3436 assert (index >= 0 && index < seq.length());
3437 return 1;
3438 }
3439 int length = seq.length();
3440 int x = index;
3441 if (lengthInCodePoints >= 0) {
3442 assert (index >= 0 && index < length);
3443 for (int i = 0; x < length && i < lengthInCodePoints; i++) {
3444 if (Character.isHighSurrogate(seq.charAt(x++))) {
3445 if (x < length && Character.isLowSurrogate(seq.charAt(x))) {
3446 x++;
3447 }
3448 }
3449 }
3450 return x - index;
3451 }
3452
3453 assert (index >= 0 && index <= length);
3454 if (index == 0) {
3455 return 0;
3456 }
3457 int len = -lengthInCodePoints;
3458 for (int i = 0; x > 0 && i < len; i++) {
3459 if (Character.isLowSurrogate(seq.charAt(--x))) {
3460 if (x > 0 && Character.isHighSurrogate(seq.charAt(x-1))) {
3461 x--;
3462 }
3463 }
3464 }
3465 return index - x;
3466 }
3467
3468 private static final int countCodePoints(CharSequence seq) {
3469 int length = seq.length();
3470 int n = 0;
3471 for (int i = 0; i < length; ) {
3472 n++;
3473 if (Character.isHighSurrogate(seq.charAt(i++))) {
3474 if (i < length && Character.isLowSurrogate(seq.charAt(i))) {
3475 i++;
3476 }
3477 }
3478 }
3479 return n;
3480 }
3481
3482 /**
3483 * Creates a bit vector for matching Latin-1 values. A normal BitClass
3484 * never matches values above Latin-1, and a complemented BitClass always
3485 * matches values above Latin-1.
3486 */
3487 static final class BitClass extends BmpCharProperty {
3488 final boolean[] bits;
3489 BitClass() {
3490 this(new boolean[256]);
3491 }
3492 private BitClass(boolean[] bits) {
3493 super( ch -> ch < 256 && bits[ch]);
3494 this.bits = bits;
3495 }
3496 BitClass add(int c, int flags) {
3497 assert c >= 0 && c <= 255;
3498 if ((flags & CASE_INSENSITIVE) != 0) {
3499 if (ASCII.isAscii(c)) {
3500 bits[ASCII.toUpper(c)] = true;
3501 bits[ASCII.toLower(c)] = true;
3502 } else if ((flags & UNICODE_CASE) != 0) {
3503 bits[Character.toLowerCase(c)] = true;
3504 bits[Character.toUpperCase(c)] = true;
3505 }
3506 }
3507 bits[c] = true;
3508 return this;
3509 }
3510 }
3511
3512 /**
3513 * Utility method for creating a string slice matcher.
3514 */
3515 private Node newSlice(int[] buf, int count, boolean hasSupplementary) {
3516 int[] tmp = new int[count];
3517 if (has(CASE_INSENSITIVE)) {
3518 if (has(UNICODE_CASE)) {
3519 for (int i = 0; i < count; i++) {
3520 tmp[i] = Character.toLowerCase(
3521 Character.toUpperCase(buf[i]));
3522 }
3523 return hasSupplementary? new SliceUS(tmp) : new SliceU(tmp);
3524 }
3525 for (int i = 0; i < count; i++) {
3526 tmp[i] = ASCII.toLower(buf[i]);
3527 }
3528 return hasSupplementary? new SliceIS(tmp) : new SliceI(tmp);
3529 }
3530 for (int i = 0; i < count; i++) {
3531 tmp[i] = buf[i];
3532 }
3533 return hasSupplementary ? new SliceS(tmp) : new Slice(tmp);
3534 }
3535
3536 /**
3537 * The following classes are the building components of the object
3538 * tree that represents a compiled regular expression. The object tree
3539 * is made of individual elements that handle constructs in the Pattern.
3540 * Each type of object knows how to match its equivalent construct with
3541 * the match() method.
3542 */
3543
3544 /**
3545 * Base class for all node classes. Subclasses should override the match()
3546 * method as appropriate. This class is an accepting node, so its match()
3547 * always returns true.
3548 */
3549 static class Node extends Object {
3550 Node next;
3551 Node() {
3552 next = Pattern.accept;
3553 }
3554 /**
3555 * This method implements the classic accept node.
3556 */
3557 boolean match(Matcher matcher, int i, CharSequence seq) {
3558 matcher.last = i;
3559 matcher.groups[0] = matcher.first;
3560 matcher.groups[1] = matcher.last;
3561 return true;
3562 }
3563 /**
3564 * This method is good for all zero length assertions.
3565 */
3566 boolean study(TreeInfo info) {
3567 if (next != null) {
3568 return next.study(info);
3569 } else {
3570 return info.deterministic;
3571 }
3572 }
3573 }
3574
3575 static class LastNode extends Node {
3576 /**
3577 * This method implements the classic accept node with
3578 * the addition of a check to see if the match occurred
3579 * using all of the input.
3580 */
3581 boolean match(Matcher matcher, int i, CharSequence seq) {
3582 if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to)
3583 return false;
3584 matcher.last = i;
3585 matcher.groups[0] = matcher.first;
3586 matcher.groups[1] = matcher.last;
3587 return true;
3588 }
3589 }
3590
3591 /**
3592 * Used for REs that can start anywhere within the input string.
3593 * This basically tries to match repeatedly at each spot in the
3594 * input string, moving forward after each try. An anchored search
3595 * or a BnM will bypass this node completely.
3596 */
3597 static class Start extends Node {
3598 int minLength;
3599 Start(Node node) {
3600 this.next = node;
3601 TreeInfo info = new TreeInfo();
3602 next.study(info);
3603 minLength = info.minLength;
3604 }
3605 boolean match(Matcher matcher, int i, CharSequence seq) {
3606 if (i > matcher.to - minLength) {
3607 matcher.hitEnd = true;
3608 return false;
3609 }
3610 int guard = matcher.to - minLength;
3611 for (; i <= guard; i++) {
3612 if (next.match(matcher, i, seq)) {
3613 matcher.first = i;
3614 matcher.groups[0] = matcher.first;
3615 matcher.groups[1] = matcher.last;
3616 return true;
3617 }
3618 }
3619 matcher.hitEnd = true;
3620 return false;
3621 }
3622 boolean study(TreeInfo info) {
3623 next.study(info);
3624 info.maxValid = false;
3625 info.deterministic = false;
3626 return false;
3627 }
3628 }
3629
3630 /*
3631 * StartS supports supplementary characters, including unpaired surrogates.
3632 */
3633 static final class StartS extends Start {
3634 StartS(Node node) {
3635 super(node);
3636 }
3637 boolean match(Matcher matcher, int i, CharSequence seq) {
3638 if (i > matcher.to - minLength) {
3639 matcher.hitEnd = true;
3640 return false;
3641 }
3642 int guard = matcher.to - minLength;
3643 while (i <= guard) {
3644 //if ((ret = next.match(matcher, i, seq)) || i == guard)
3645 if (next.match(matcher, i, seq)) {
3646 matcher.first = i;
3647 matcher.groups[0] = matcher.first;
3648 matcher.groups[1] = matcher.last;
3649 return true;
3650 }
3651 if (i == guard)
3652 break;
3653 // Optimization to move to the next character. This is
3654 // faster than countChars(seq, i, 1).
3655 if (Character.isHighSurrogate(seq.charAt(i++))) {
3656 if (i < seq.length() &&
3657 Character.isLowSurrogate(seq.charAt(i))) {
3658 i++;
3659 }
3660 }
3661 }
3662 matcher.hitEnd = true;
3663 return false;
3664 }
3665 }
3666
3667 /**
3668 * Node to anchor at the beginning of input. This object implements the
3669 * match for a \A sequence, and the caret anchor will use this if not in
3670 * multiline mode.
3671 */
3672 static final class Begin extends Node {
3673 boolean match(Matcher matcher, int i, CharSequence seq) {
3674 int fromIndex = (matcher.anchoringBounds) ?
3675 matcher.from : 0;
3676 if (i == fromIndex && next.match(matcher, i, seq)) {
3677 matcher.first = i;
3678 matcher.groups[0] = i;
3679 matcher.groups[1] = matcher.last;
3680 return true;
3681 } else {
3682 return false;
3683 }
3684 }
3685 }
3686
3687 /**
3688 * Node to anchor at the end of input. This is the absolute end, so this
3689 * should not match at the last newline before the end as $ will.
3690 */
3691 static final class End extends Node {
3692 boolean match(Matcher matcher, int i, CharSequence seq) {
3693 int endIndex = (matcher.anchoringBounds) ?
3694 matcher.to : matcher.getTextLength();
3695 if (i == endIndex) {
3696 matcher.hitEnd = true;
3697 return next.match(matcher, i, seq);
3698 }
3699 return false;
3700 }
3701 }
3702
3703 /**
3704 * Node to anchor at the beginning of a line. This is essentially the
3705 * object to match for the multiline ^.
3706 */
3707 static final class Caret extends Node {
3708 boolean match(Matcher matcher, int i, CharSequence seq) {
3709 int startIndex = matcher.from;
3710 int endIndex = matcher.to;
3711 if (!matcher.anchoringBounds) {
3712 startIndex = 0;
3713 endIndex = matcher.getTextLength();
3714 }
3715 // Perl does not match ^ at end of input even after newline
3716 if (i == endIndex) {
3717 matcher.hitEnd = true;
3718 return false;
3719 }
3720 if (i > startIndex) {
3721 char ch = seq.charAt(i-1);
3722 if (ch != '\n' && ch != '\r'
3723 && (ch|1) != '\u2029'
3724 && ch != '\u0085' ) {
3725 return false;
3726 }
3727 // Should treat /r/n as one newline
3728 if (ch == '\r' && seq.charAt(i) == '\n')
3729 return false;
3730 }
3731 return next.match(matcher, i, seq);
3732 }
3733 }
3734
3735 /**
3736 * Node to anchor at the beginning of a line when in unixdot mode.
3737 */
3738 static final class UnixCaret extends Node {
3739 boolean match(Matcher matcher, int i, CharSequence seq) {
3740 int startIndex = matcher.from;
3741 int endIndex = matcher.to;
3742 if (!matcher.anchoringBounds) {
3743 startIndex = 0;
3744 endIndex = matcher.getTextLength();
3745 }
3746 // Perl does not match ^ at end of input even after newline
3747 if (i == endIndex) {
3748 matcher.hitEnd = true;
3749 return false;
3750 }
3751 if (i > startIndex) {
3752 char ch = seq.charAt(i-1);
3753 if (ch != '\n') {
3754 return false;
3755 }
3756 }
3757 return next.match(matcher, i, seq);
3758 }
3759 }
3760
3761 /**
3762 * Node to match the location where the last match ended.
3763 * This is used for the \G construct.
3764 */
3765 static final class LastMatch extends Node {
3766 boolean match(Matcher matcher, int i, CharSequence seq) {
3767 if (i != matcher.oldLast)
3768 return false;
3769 return next.match(matcher, i, seq);
3770 }
3771 }
3772
3773 /**
3774 * Node to anchor at the end of a line or the end of input based on the
3775 * multiline mode.
3776 *
3777 * When not in multiline mode, the $ can only match at the very end
3778 * of the input, unless the input ends in a line terminator in which
3779 * it matches right before the last line terminator.
3780 *
3781 * Note that \r\n is considered an atomic line terminator.
3782 *
3783 * Like ^ the $ operator matches at a position, it does not match the
3784 * line terminators themselves.
3785 */
3786 static final class Dollar extends Node {
3787 boolean multiline;
3788 Dollar(boolean mul) {
3789 multiline = mul;
3790 }
3791 boolean match(Matcher matcher, int i, CharSequence seq) {
3792 int endIndex = (matcher.anchoringBounds) ?
3793 matcher.to : matcher.getTextLength();
3794 if (!multiline) {
3795 if (i < endIndex - 2)
3796 return false;
3797 if (i == endIndex - 2) {
3798 char ch = seq.charAt(i);
3799 if (ch != '\r')
3800 return false;
3801 ch = seq.charAt(i + 1);
3802 if (ch != '\n')
3803 return false;
3804 }
3805 }
3806 // Matches before any line terminator; also matches at the
3807 // end of input
3808 // Before line terminator:
3809 // If multiline, we match here no matter what
3810 // If not multiline, fall through so that the end
3811 // is marked as hit; this must be a /r/n or a /n
3812 // at the very end so the end was hit; more input
3813 // could make this not match here
3814 if (i < endIndex) {
3815 char ch = seq.charAt(i);
3816 if (ch == '\n') {
3817 // No match between \r\n
3818 if (i > 0 && seq.charAt(i-1) == '\r')
3819 return false;
3820 if (multiline)
3821 return next.match(matcher, i, seq);
3822 } else if (ch == '\r' || ch == '\u0085' ||
3823 (ch|1) == '\u2029') {
3824 if (multiline)
3825 return next.match(matcher, i, seq);
3826 } else { // No line terminator, no match
3827 return false;
3828 }
3829 }
3830 // Matched at current end so hit end
3831 matcher.hitEnd = true;
3832 // If a $ matches because of end of input, then more input
3833 // could cause it to fail!
3834 matcher.requireEnd = true;
3835 return next.match(matcher, i, seq);
3836 }
3837 boolean study(TreeInfo info) {
3838 next.study(info);
3839 return info.deterministic;
3840 }
3841 }
3842
3843 /**
3844 * Node to anchor at the end of a line or the end of input based on the
3845 * multiline mode when in unix lines mode.
3846 */
3847 static final class UnixDollar extends Node {
3848 boolean multiline;
3849 UnixDollar(boolean mul) {
3850 multiline = mul;
3851 }
3852 boolean match(Matcher matcher, int i, CharSequence seq) {
3853 int endIndex = (matcher.anchoringBounds) ?
3854 matcher.to : matcher.getTextLength();
3855 if (i < endIndex) {
3856 char ch = seq.charAt(i);
3857 if (ch == '\n') {
3858 // If not multiline, then only possible to
3859 // match at very end or one before end
3860 if (multiline == false && i != endIndex - 1)
3861 return false;
3862 // If multiline return next.match without setting
3863 // matcher.hitEnd
3864 if (multiline)
3865 return next.match(matcher, i, seq);
3866 } else {
3867 return false;
3868 }
3869 }
3870 // Matching because at the end or 1 before the end;
3871 // more input could change this so set hitEnd
3872 matcher.hitEnd = true;
3873 // If a $ matches because of end of input, then more input
3874 // could cause it to fail!
3875 matcher.requireEnd = true;
3876 return next.match(matcher, i, seq);
3877 }
3878 boolean study(TreeInfo info) {
3879 next.study(info);
3880 return info.deterministic;
3881 }
3882 }
3883
3884 /**
3885 * Node class that matches a Unicode line ending '\R'
3886 */
3887 static final class LineEnding extends Node {
3888 boolean match(Matcher matcher, int i, CharSequence seq) {
3889 // (u+000Du+000A|[u+000Au+000Bu+000Cu+000Du+0085u+2028u+2029])
3890 if (i < matcher.to) {
3891 int ch = seq.charAt(i);
3892 if (ch == 0x0A || ch == 0x0B || ch == 0x0C ||
3893 ch == 0x85 || ch == 0x2028 || ch == 0x2029)
3894 return next.match(matcher, i + 1, seq);
3895 if (ch == 0x0D) {
3896 i++;
3897 if (i < matcher.to) {
3898 if (seq.charAt(i) == 0x0A &&
3899 next.match(matcher, i + 1, seq)) {
3900 return true;
3901 }
3902 } else {
3903 matcher.hitEnd = true;
3904 }
3905 return next.match(matcher, i, seq);
3906 }
3907 } else {
3908 matcher.hitEnd = true;
3909 }
3910 return false;
3911 }
3912 boolean study(TreeInfo info) {
3913 info.minLength++;
3914 info.maxLength += 2;
3915 return next.study(info);
3916 }
3917 }
3918
3919 /**
3920 * Abstract node class to match one character satisfying some
3921 * boolean property.
3922 */
3923 static class CharProperty extends Node {
3924 CharPredicate predicate;
3925
3926 CharProperty (CharPredicate predicate) {
3927 this.predicate = predicate;
3928 }
3929 boolean match(Matcher matcher, int i, CharSequence seq) {
3930 if (i < matcher.to) {
3931 int ch = Character.codePointAt(seq, i);
3932 return predicate.is(ch) &&
3933 next.match(matcher, i + Character.charCount(ch), seq);
3934 } else {
3935 matcher.hitEnd = true;
3936 return false;
3937 }
3938 }
3939 boolean study(TreeInfo info) {
3940 info.minLength++;
3941 info.maxLength++;
3942 return next.study(info);
3943 }
3944 }
3945
3946 /**
3947 * Optimized version of CharProperty that works only for
3948 * properties never satisfied by Supplementary characters.
3949 */
3950 private static class BmpCharProperty extends CharProperty {
3951 BmpCharProperty (BmpCharPredicate predicate) {
3952 super(predicate);
3953 }
3954 boolean match(Matcher matcher, int i, CharSequence seq) {
3955 if (i < matcher.to) {
3956 return predicate.is(seq.charAt(i)) &&
3957 next.match(matcher, i + 1, seq);
3958 } else {
3959 matcher.hitEnd = true;
3960 return false;
3961 }
3962 }
3963 }
3964
3965 private static class NFCCharProperty extends Node {
3966 CharPredicate predicate;
3967 NFCCharProperty (CharPredicate predicate) {
3968 this.predicate = predicate;
3969 }
3970
3971 boolean match(Matcher matcher, int i, CharSequence seq) {
3972 if (i < matcher.to) {
3973 int ch0 = Character.codePointAt(seq, i);
3974 int n = Character.charCount(ch0);
3975 int j = i + n;
3976 while (j < matcher.to) {
3977 int ch1 = Character.codePointAt(seq, j);
3978 if (Grapheme.isBoundary(ch0, ch1))
3979 break;
3980 ch0 = ch1;
3981 j += Character.charCount(ch1);
3982 }
3983 if (i + n == j) { // single, assume nfc cp
3984 if (predicate.is(ch0))
3985 return next.match(matcher, j, seq);
3986 } else {
3987 while (i + n < j) {
3988 String nfc = Normalizer.normalize(
3989 seq.toString().substring(i, j), Normalizer.Form.NFC);
3990 if (nfc.codePointCount(0, nfc.length()) == 1) {
3991 if (predicate.is(nfc.codePointAt(0)) &&
3992 next.match(matcher, j, seq)) {
3993 return true;
3994 }
3995 }
3996
3997 ch0 = Character.codePointBefore(seq, j);
3998 j -= Character.charCount(ch0);
3999 }
4000 }
4001 if (j < matcher.to)
4002 return false;
4003 }
4004 matcher.hitEnd = true;
4005 return false;
4006 }
4007
4008 boolean study(TreeInfo info) {
4009 info.minLength++;
4010 info.deterministic = false;
4011 return next.study(info);
4012 }
4013 }
4014
4015 /**
4016 * Node class that matches an unicode extended grapheme cluster
4017 */
4018 static class XGrapheme extends Node {
4019 boolean match(Matcher matcher, int i, CharSequence seq) {
4020 if (i < matcher.to) {
4021 int ch0 = Character.codePointAt(seq, i);
4022 i += Character.charCount(ch0);
4023 while (i < matcher.to) {
4024 int ch1 = Character.codePointAt(seq, i);
4025 if (Grapheme.isBoundary(ch0, ch1))
4026 break;
4027 ch0 = ch1;
4028 i += Character.charCount(ch1);
4029 }
4030 return next.match(matcher, i, seq);
4031 }
4032 matcher.hitEnd = true;
4033 return false;
4034 }
4035
4036 boolean study(TreeInfo info) {
4037 info.minLength++;
4038 info.deterministic = false;
4039 return next.study(info);
4040 }
4041 }
4042
4043 /**
4044 * Node class that handles grapheme boundaries
4045 */
4046 static class GraphemeBound extends Node {
4047 boolean match(Matcher matcher, int i, CharSequence seq) {
4048 int startIndex = matcher.from;
4049 int endIndex = matcher.to;
4050 if (matcher.transparentBounds) {
4051 startIndex = 0;
4052 endIndex = matcher.getTextLength();
4053 }
4054 if (i == startIndex) {
4055 return next.match(matcher, i, seq);
4056 }
4057 if (i < endIndex) {
4058 if (Character.isSurrogatePair(seq.charAt(i-1), seq.charAt(i)) ||
4059 !Grapheme.isBoundary(Character.codePointBefore(seq, i),
4060 Character.codePointAt(seq, i))) {
4061 return false;
4062 }
4063 } else {
4064 matcher.hitEnd = true;
4065 matcher.requireEnd = true;
4066 }
4067 return next.match(matcher, i, seq);
4068 }
4069 }
4070
4071 /**
4072 * Base class for all Slice nodes
4073 */
4074 static class SliceNode extends Node {
4075 int[] buffer;
4076 SliceNode(int[] buf) {
4077 buffer = buf;
4078 }
4079 boolean study(TreeInfo info) {
4080 info.minLength += buffer.length;
4081 info.maxLength += buffer.length;
4082 return next.study(info);
4083 }
4084 }
4085
4086 /**
4087 * Node class for a case sensitive/BMP-only sequence of literal
4088 * characters.
4089 */
4090 static class Slice extends SliceNode {
4091 Slice(int[] buf) {
4092 super(buf);
4093 }
4094 boolean match(Matcher matcher, int i, CharSequence seq) {
4095 int[] buf = buffer;
4096 int len = buf.length;
4097 for (int j=0; j<len; j++) {
4098 if ((i+j) >= matcher.to) {
4099 matcher.hitEnd = true;
4100 return false;
4101 }
4102 if (buf[j] != seq.charAt(i+j))
4103 return false;
4104 }
4105 return next.match(matcher, i+len, seq);
4106 }
4107 }
4108
4109 /**
4110 * Node class for a case_insensitive/BMP-only sequence of literal
4111 * characters.
4112 */
4113 static class SliceI extends SliceNode {
4114 SliceI(int[] buf) {
4115 super(buf);
4116 }
4117 boolean match(Matcher matcher, int i, CharSequence seq) {
4118 int[] buf = buffer;
4119 int len = buf.length;
4120 for (int j=0; j<len; j++) {
4121 if ((i+j) >= matcher.to) {
4122 matcher.hitEnd = true;
4123 return false;
4124 }
4125 int c = seq.charAt(i+j);
4126 if (buf[j] != c &&
4127 buf[j] != ASCII.toLower(c))
4128 return false;
4129 }
4130 return next.match(matcher, i+len, seq);
4131 }
4132 }
4133
4134 /**
4135 * Node class for a unicode_case_insensitive/BMP-only sequence of
4136 * literal characters. Uses unicode case folding.
4137 */
4138 static final class SliceU extends SliceNode {
4139 SliceU(int[] buf) {
4140 super(buf);
4141 }
4142 boolean match(Matcher matcher, int i, CharSequence seq) {
4143 int[] buf = buffer;
4144 int len = buf.length;
4145 for (int j=0; j<len; j++) {
4146 if ((i+j) >= matcher.to) {
4147 matcher.hitEnd = true;
4148 return false;
4149 }
4150 int c = seq.charAt(i+j);
4151 if (buf[j] != c &&
4152 buf[j] != Character.toLowerCase(Character.toUpperCase(c)))
4153 return false;
4154 }
4155 return next.match(matcher, i+len, seq);
4156 }
4157 }
4158
4159 /**
4160 * Node class for a case sensitive sequence of literal characters
4161 * including supplementary characters.
4162 */
4163 static final class SliceS extends Slice {
4164 SliceS(int[] buf) {
4165 super(buf);
4166 }
4167 boolean match(Matcher matcher, int i, CharSequence seq) {
4168 int[] buf = buffer;
4169 int x = i;
4170 for (int j = 0; j < buf.length; j++) {
4171 if (x >= matcher.to) {
4172 matcher.hitEnd = true;
4173 return false;
4174 }
4175 int c = Character.codePointAt(seq, x);
4176 if (buf[j] != c)
4177 return false;
4178 x += Character.charCount(c);
4179 if (x > matcher.to) {
4180 matcher.hitEnd = true;
4181 return false;
4182 }
4183 }
4184 return next.match(matcher, x, seq);
4185 }
4186 }
4187
4188 /**
4189 * Node class for a case insensitive sequence of literal characters
4190 * including supplementary characters.
4191 */
4192 static class SliceIS extends SliceNode {
4193 SliceIS(int[] buf) {
4194 super(buf);
4195 }
4196 int toLower(int c) {
4197 return ASCII.toLower(c);
4198 }
4199 boolean match(Matcher matcher, int i, CharSequence seq) {
4200 int[] buf = buffer;
4201 int x = i;
4202 for (int j = 0; j < buf.length; j++) {
4203 if (x >= matcher.to) {
4204 matcher.hitEnd = true;
4205 return false;
4206 }
4207 int c = Character.codePointAt(seq, x);
4208 if (buf[j] != c && buf[j] != toLower(c))
4209 return false;
4210 x += Character.charCount(c);
4211 if (x > matcher.to) {
4212 matcher.hitEnd = true;
4213 return false;
4214 }
4215 }
4216 return next.match(matcher, x, seq);
4217 }
4218 }
4219
4220 /**
4221 * Node class for a case insensitive sequence of literal characters.
4222 * Uses unicode case folding.
4223 */
4224 static final class SliceUS extends SliceIS {
4225 SliceUS(int[] buf) {
4226 super(buf);
4227 }
4228 int toLower(int c) {
4229 return Character.toLowerCase(Character.toUpperCase(c));
4230 }
4231 }
4232
4233 /**
4234 * The 0 or 1 quantifier. This one class implements all three types.
4235 */
4236 static final class Ques extends Node {
4237 Node atom;
4238 Qtype type;
4239 Ques(Node node, Qtype type) {
4240 this.atom = node;
4241 this.type = type;
4242 }
4243 boolean match(Matcher matcher, int i, CharSequence seq) {
4244 switch (type) {
4245 case GREEDY:
4246 return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq))
4247 || next.match(matcher, i, seq);
4248 case LAZY:
4249 return next.match(matcher, i, seq)
4250 || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq));
4251 case POSSESSIVE:
4252 if (atom.match(matcher, i, seq)) i = matcher.last;
4253 return next.match(matcher, i, seq);
4254 default:
4255 return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq);
4256 }
4257 }
4258 boolean study(TreeInfo info) {
4259 if (type != Qtype.INDEPENDENT) {
4260 int minL = info.minLength;
4261 atom.study(info);
4262 info.minLength = minL;
4263 info.deterministic = false;
4264 return next.study(info);
4265 } else {
4266 atom.study(info);
4267 return next.study(info);
4268 }
4269 }
4270 }
4271
4272 /**
4273 * Handles the greedy style repetition with the minimum either be
4274 * 0 or 1 and the maximum be MAX_REPS, for * and + quantifier.
4275 */
4276 static class CharPropertyGreedy extends Node {
4277 final CharPredicate predicate;
4278 final int cmin;
4279
4280 CharPropertyGreedy(CharProperty cp, int cmin) {
4281 this.predicate = cp.predicate;
4282 this.cmin = cmin;
4283 }
4284 boolean match(Matcher matcher, int i, CharSequence seq) {
4285 int n = 0;
4286 int to = matcher.to;
4287 // greedy, all the way down
4288 while (i < to) {
4289 int ch = Character.codePointAt(seq, i);
4290 if (!predicate.is(ch))
4291 break;
4292 i += Character.charCount(ch);
4293 n++;
4294 }
4295 if (i >= to) {
4296 matcher.hitEnd = true;
4297 }
4298 while (n >= cmin) {
4299 if (next.match(matcher, i, seq))
4300 return true;
4301 if (n == cmin)
4302 return false;
4303 // backing off if match fails
4304 int ch = Character.codePointBefore(seq, i);
4305 i -= Character.charCount(ch);
4306 n--;
4307 }
4308 return false;
4309 }
4310
4311 boolean study(TreeInfo info) {
4312 info.minLength += cmin;
4313 if (info.maxValid) {
4314 info.maxLength += MAX_REPS;
4315 }
4316 info.deterministic = false;
4317 return next.study(info);
4318 }
4319 }
4320
4321 static final class BmpCharPropertyGreedy extends CharPropertyGreedy {
4322
4323 BmpCharPropertyGreedy(BmpCharProperty bcp, int cmin) {
4324 super(bcp, cmin);
4325 }
4326
4327 boolean match(Matcher matcher, int i, CharSequence seq) {
4328 int n = 0;
4329 int to = matcher.to;
4330 while (i < to && predicate.is(seq.charAt(i))) {
4331 i++; n++;
4332 }
4333 if (i >= to) {
4334 matcher.hitEnd = true;
4335 }
4336 while (n >= cmin) {
4337 if (next.match(matcher, i, seq))
4338 return true;
4339 i--; n--; // backing off if match fails
4340 }
4341 return false;
4342 }
4343 }
4344
4345 /**
4346 * Handles the curly-brace style repetition with a specified minimum and
4347 * maximum occurrences. The * quantifier is handled as a special case.
4348 * This class handles the three types.
4349 */
4350 static final class Curly extends Node {
4351 Node atom;
4352 Qtype type;
4353 int cmin;
4354 int cmax;
4355
4356 Curly(Node node, int cmin, int cmax, Qtype type) {
4357 this.atom = node;
4358 this.type = type;
4359 this.cmin = cmin;
4360 this.cmax = cmax;
4361 }
4362 boolean match(Matcher matcher, int i, CharSequence seq) {
4363 int j;
4364 for (j = 0; j < cmin; j++) {
4365 if (atom.match(matcher, i, seq)) {
4366 i = matcher.last;
4367 continue;
4368 }
4369 return false;
4370 }
4371 if (type == Qtype.GREEDY)
4372 return match0(matcher, i, j, seq);
4373 else if (type == Qtype.LAZY)
4374 return match1(matcher, i, j, seq);
4375 else
4376 return match2(matcher, i, j, seq);
4377 }
4378 // Greedy match.
4379 // i is the index to start matching at
4380 // j is the number of atoms that have matched
4381 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4382 if (j >= cmax) {
4383 // We have matched the maximum... continue with the rest of
4384 // the regular expression
4385 return next.match(matcher, i, seq);
4386 }
4387 int backLimit = j;
4388 while (atom.match(matcher, i, seq)) {
4389 // k is the length of this match
4390 int k = matcher.last - i;
4391 if (k == 0) // Zero length match
4392 break;
4393 // Move up index and number matched
4394 i = matcher.last;
4395 j++;
4396 // We are greedy so match as many as we can
4397 while (j < cmax) {
4398 if (!atom.match(matcher, i, seq))
4399 break;
4400 if (i + k != matcher.last) {
4401 if (match0(matcher, matcher.last, j+1, seq))
4402 return true;
4403 break;
4404 }
4405 i += k;
4406 j++;
4407 }
4408 // Handle backing off if match fails
4409 while (j >= backLimit) {
4410 if (next.match(matcher, i, seq))
4411 return true;
4412 i -= k;
4413 j--;
4414 }
4415 return false;
4416 }
4417 return next.match(matcher, i, seq);
4418 }
4419 // Reluctant match. At this point, the minimum has been satisfied.
4420 // i is the index to start matching at
4421 // j is the number of atoms that have matched
4422 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4423 for (;;) {
4424 // Try finishing match without consuming any more
4425 if (next.match(matcher, i, seq))
4426 return true;
4427 // At the maximum, no match found
4428 if (j >= cmax)
4429 return false;
4430 // Okay, must try one more atom
4431 if (!atom.match(matcher, i, seq))
4432 return false;
4433 // If we haven't moved forward then must break out
4434 if (i == matcher.last)
4435 return false;
4436 // Move up index and number matched
4437 i = matcher.last;
4438 j++;
4439 }
4440 }
4441 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4442 for (; j < cmax; j++) {
4443 if (!atom.match(matcher, i, seq))
4444 break;
4445 if (i == matcher.last)
4446 break;
4447 i = matcher.last;
4448 }
4449 return next.match(matcher, i, seq);
4450 }
4451 boolean study(TreeInfo info) {
4452 // Save original info
4453 int minL = info.minLength;
4454 int maxL = info.maxLength;
4455 boolean maxV = info.maxValid;
4456 boolean detm = info.deterministic;
4457 info.reset();
4458
4459 atom.study(info);
4460
4461 int temp = info.minLength * cmin + minL;
4462 if (temp < minL) {
4463 temp = 0xFFFFFFF; // arbitrary large number
4464 }
4465 info.minLength = temp;
4466
4467 if (maxV & info.maxValid) {
4468 temp = info.maxLength * cmax + maxL;
4469 info.maxLength = temp;
4470 if (temp < maxL) {
4471 info.maxValid = false;
4472 }
4473 } else {
4474 info.maxValid = false;
4475 }
4476
4477 if (info.deterministic && cmin == cmax)
4478 info.deterministic = detm;
4479 else
4480 info.deterministic = false;
4481 return next.study(info);
4482 }
4483 }
4484
4485 /**
4486 * Handles the curly-brace style repetition with a specified minimum and
4487 * maximum occurrences in deterministic cases. This is an iterative
4488 * optimization over the Prolog and Loop system which would handle this
4489 * in a recursive way. The * quantifier is handled as a special case.
4490 * If capture is true then this class saves group settings and ensures
4491 * that groups are unset when backing off of a group match.
4492 */
4493 static final class GroupCurly extends Node {
4494 Node atom;
4495 Qtype type;
4496 int cmin;
4497 int cmax;
4498 int localIndex;
4499 int groupIndex;
4500 boolean capture;
4501
4502 GroupCurly(Node node, int cmin, int cmax, Qtype type, int local,
4503 int group, boolean capture) {
4504 this.atom = node;
4505 this.type = type;
4506 this.cmin = cmin;
4507 this.cmax = cmax;
4508 this.localIndex = local;
4509 this.groupIndex = group;
4510 this.capture = capture;
4511 }
4512 boolean match(Matcher matcher, int i, CharSequence seq) {
4513 int[] groups = matcher.groups;
4514 int[] locals = matcher.locals;
4515 int save0 = locals[localIndex];
4516 int save1 = 0;
4517 int save2 = 0;
4518
4519 if (capture) {
4520 save1 = groups[groupIndex];
4521 save2 = groups[groupIndex+1];
4522 }
4523
4524 // Notify GroupTail there is no need to setup group info
4525 // because it will be set here
4526 locals[localIndex] = -1;
4527
4528 boolean ret = true;
4529 for (int j = 0; j < cmin; j++) {
4530 if (atom.match(matcher, i, seq)) {
4531 if (capture) {
4532 groups[groupIndex] = i;
4533 groups[groupIndex+1] = matcher.last;
4534 }
4535 i = matcher.last;
4536 } else {
4537 ret = false;
4538 break;
4539 }
4540 }
4541 if (ret) {
4542 if (type == Qtype.GREEDY) {
4543 ret = match0(matcher, i, cmin, seq);
4544 } else if (type == Qtype.LAZY) {
4545 ret = match1(matcher, i, cmin, seq);
4546 } else {
4547 ret = match2(matcher, i, cmin, seq);
4548 }
4549 }
4550 if (!ret) {
4551 locals[localIndex] = save0;
4552 if (capture) {
4553 groups[groupIndex] = save1;
4554 groups[groupIndex+1] = save2;
4555 }
4556 }
4557 return ret;
4558 }
4559 // Aggressive group match
4560 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4561 // don't back off passing the starting "j"
4562 int min = j;
4563 int[] groups = matcher.groups;
4564 int save0 = 0;
4565 int save1 = 0;
4566 if (capture) {
4567 save0 = groups[groupIndex];
4568 save1 = groups[groupIndex+1];
4569 }
4570 for (;;) {
4571 if (j >= cmax)
4572 break;
4573 if (!atom.match(matcher, i, seq))
4574 break;
4575 int k = matcher.last - i;
4576 if (k <= 0) {
4577 if (capture) {
4578 groups[groupIndex] = i;
4579 groups[groupIndex+1] = i + k;
4580 }
4581 i = i + k;
4582 break;
4583 }
4584 for (;;) {
4585 if (capture) {
4586 groups[groupIndex] = i;
4587 groups[groupIndex+1] = i + k;
4588 }
4589 i = i + k;
4590 if (++j >= cmax)
4591 break;
4592 if (!atom.match(matcher, i, seq))
4593 break;
4594 if (i + k != matcher.last) {
4595 if (match0(matcher, i, j, seq))
4596 return true;
4597 break;
4598 }
4599 }
4600 while (j > min) {
4601 if (next.match(matcher, i, seq)) {
4602 if (capture) {
4603 groups[groupIndex+1] = i;
4604 groups[groupIndex] = i - k;
4605 }
4606 return true;
4607 }
4608 // backing off
4609 i = i - k;
4610 if (capture) {
4611 groups[groupIndex+1] = i;
4612 groups[groupIndex] = i - k;
4613 }
4614 j--;
4615
4616 }
4617 break;
4618 }
4619 if (capture) {
4620 groups[groupIndex] = save0;
4621 groups[groupIndex+1] = save1;
4622 }
4623 return next.match(matcher, i, seq);
4624 }
4625 // Reluctant matching
4626 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4627 for (;;) {
4628 if (next.match(matcher, i, seq))
4629 return true;
4630 if (j >= cmax)
4631 return false;
4632 if (!atom.match(matcher, i, seq))
4633 return false;
4634 if (i == matcher.last)
4635 return false;
4636 if (capture) {
4637 matcher.groups[groupIndex] = i;
4638 matcher.groups[groupIndex+1] = matcher.last;
4639 }
4640 i = matcher.last;
4641 j++;
4642 }
4643 }
4644 // Possessive matching
4645 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4646 for (; j < cmax; j++) {
4647 if (!atom.match(matcher, i, seq)) {
4648 break;
4649 }
4650 if (capture) {
4651 matcher.groups[groupIndex] = i;
4652 matcher.groups[groupIndex+1] = matcher.last;
4653 }
4654 if (i == matcher.last) {
4655 break;
4656 }
4657 i = matcher.last;
4658 }
4659 return next.match(matcher, i, seq);
4660 }
4661 boolean study(TreeInfo info) {
4662 // Save original info
4663 int minL = info.minLength;
4664 int maxL = info.maxLength;
4665 boolean maxV = info.maxValid;
4666 boolean detm = info.deterministic;
4667 info.reset();
4668
4669 atom.study(info);
4670
4671 int temp = info.minLength * cmin + minL;
4672 if (temp < minL) {
4673 temp = 0xFFFFFFF; // Arbitrary large number
4674 }
4675 info.minLength = temp;
4676
4677 if (maxV & info.maxValid) {
4678 temp = info.maxLength * cmax + maxL;
4679 info.maxLength = temp;
4680 if (temp < maxL) {
4681 info.maxValid = false;
4682 }
4683 } else {
4684 info.maxValid = false;
4685 }
4686
4687 if (info.deterministic && cmin == cmax) {
4688 info.deterministic = detm;
4689 } else {
4690 info.deterministic = false;
4691 }
4692 return next.study(info);
4693 }
4694 }
4695
4696 /**
4697 * A Guard node at the end of each atom node in a Branch. It
4698 * serves the purpose of chaining the "match" operation to
4699 * "next" but not the "study", so we can collect the TreeInfo
4700 * of each atom node without including the TreeInfo of the
4701 * "next".
4702 */
4703 static final class BranchConn extends Node {
4704 BranchConn() {};
4705 boolean match(Matcher matcher, int i, CharSequence seq) {
4706 return next.match(matcher, i, seq);
4707 }
4708 boolean study(TreeInfo info) {
4709 return info.deterministic;
4710 }
4711 }
4712
4713 /**
4714 * Handles the branching of alternations. Note this is also used for
4715 * the ? quantifier to branch between the case where it matches once
4716 * and where it does not occur.
4717 */
4718 static final class Branch extends Node {
4719 Node[] atoms = new Node[2];
4720 int size = 2;
4721 Node conn;
4722 Branch(Node first, Node second, Node branchConn) {
4723 conn = branchConn;
4724 atoms[0] = first;
4725 atoms[1] = second;
4726 }
4727
4728 void add(Node node) {
4729 if (size >= atoms.length) {
4730 Node[] tmp = new Node[atoms.length*2];
4731 System.arraycopy(atoms, 0, tmp, 0, atoms.length);
4732 atoms = tmp;
4733 }
4734 atoms[size++] = node;
4735 }
4736
4737 boolean match(Matcher matcher, int i, CharSequence seq) {
4738 for (int n = 0; n < size; n++) {
4739 if (atoms[n] == null) {
4740 if (conn.next.match(matcher, i, seq))
4741 return true;
4742 } else if (atoms[n].match(matcher, i, seq)) {
4743 return true;
4744 }
4745 }
4746 return false;
4747 }
4748
4749 boolean study(TreeInfo info) {
4750 int minL = info.minLength;
4751 int maxL = info.maxLength;
4752 boolean maxV = info.maxValid;
4753
4754 int minL2 = Integer.MAX_VALUE; //arbitrary large enough num
4755 int maxL2 = -1;
4756 for (int n = 0; n < size; n++) {
4757 info.reset();
4758 if (atoms[n] != null)
4759 atoms[n].study(info);
4760 minL2 = Math.min(minL2, info.minLength);
4761 maxL2 = Math.max(maxL2, info.maxLength);
4762 maxV = (maxV & info.maxValid);
4763 }
4764
4765 minL += minL2;
4766 maxL += maxL2;
4767
4768 info.reset();
4769 conn.next.study(info);
4770
4771 info.minLength += minL;
4772 info.maxLength += maxL;
4773 info.maxValid &= maxV;
4774 info.deterministic = false;
4775 return false;
4776 }
4777 }
4778
4779 /**
4780 * The GroupHead saves the location where the group begins in the locals
4781 * and restores them when the match is done.
4782 *
4783 * The matchRef is used when a reference to this group is accessed later
4784 * in the expression. The locals will have a negative value in them to
4785 * indicate that we do not want to unset the group if the reference
4786 * doesn't match.
4787 */
4788 static final class GroupHead extends Node {
4789 int localIndex;
4790 GroupTail tail; // for debug/print only, match does not need to know
4791 GroupHead(int localCount) {
4792 localIndex = localCount;
4793 }
4794 boolean match(Matcher matcher, int i, CharSequence seq) {
4795 int save = matcher.locals[localIndex];
4796 matcher.locals[localIndex] = i;
4797 boolean ret = next.match(matcher, i, seq);
4798 matcher.locals[localIndex] = save;
4799 return ret;
4800 }
4801 boolean matchRef(Matcher matcher, int i, CharSequence seq) {
4802 int save = matcher.locals[localIndex];
4803 matcher.locals[localIndex] = ~i; // HACK
4804 boolean ret = next.match(matcher, i, seq);
4805 matcher.locals[localIndex] = save;
4806 return ret;
4807 }
4808 }
4809
4810 /**
4811 * Recursive reference to a group in the regular expression. It calls
4812 * matchRef because if the reference fails to match we would not unset
4813 * the group.
4814 */
4815 static final class GroupRef extends Node {
4816 GroupHead head;
4817 GroupRef(GroupHead head) {
4818 this.head = head;
4819 }
4820 boolean match(Matcher matcher, int i, CharSequence seq) {
4821 return head.matchRef(matcher, i, seq)
4822 && next.match(matcher, matcher.last, seq);
4823 }
4824 boolean study(TreeInfo info) {
4825 info.maxValid = false;
4826 info.deterministic = false;
4827 return next.study(info);
4828 }
4829 }
4830
4831 /**
4832 * The GroupTail handles the setting of group beginning and ending
4833 * locations when groups are successfully matched. It must also be able to
4834 * unset groups that have to be backed off of.
4835 *
4836 * The GroupTail node is also used when a previous group is referenced,
4837 * and in that case no group information needs to be set.
4838 */
4839 static final class GroupTail extends Node {
4840 int localIndex;
4841 int groupIndex;
4842 GroupTail(int localCount, int groupCount) {
4843 localIndex = localCount;
4844 groupIndex = groupCount + groupCount;
4845 }
4846 boolean match(Matcher matcher, int i, CharSequence seq) {
4847 int tmp = matcher.locals[localIndex];
4848 if (tmp >= 0) { // This is the normal group case.
4849 // Save the group so we can unset it if it
4850 // backs off of a match.
4851 int groupStart = matcher.groups[groupIndex];
4852 int groupEnd = matcher.groups[groupIndex+1];
4853
4854 matcher.groups[groupIndex] = tmp;
4855 matcher.groups[groupIndex+1] = i;
4856 if (next.match(matcher, i, seq)) {
4857 return true;
4858 }
4859 matcher.groups[groupIndex] = groupStart;
4860 matcher.groups[groupIndex+1] = groupEnd;
4861 return false;
4862 } else {
4863 // This is a group reference case. We don't need to save any
4864 // group info because it isn't really a group.
4865 matcher.last = i;
4866 return true;
4867 }
4868 }
4869 }
4870
4871 /**
4872 * This sets up a loop to handle a recursive quantifier structure.
4873 */
4874 static final class Prolog extends Node {
4875 Loop loop;
4876 Prolog(Loop loop) {
4877 this.loop = loop;
4878 }
4879 boolean match(Matcher matcher, int i, CharSequence seq) {
4880 return loop.matchInit(matcher, i, seq);
4881 }
4882 boolean study(TreeInfo info) {
4883 return loop.study(info);
4884 }
4885 }
4886
4887 /**
4888 * Handles the repetition count for a greedy Curly. The matchInit
4889 * is called from the Prolog to save the index of where the group
4890 * beginning is stored. A zero length group check occurs in the
4891 * normal match but is skipped in the matchInit.
4892 */
4893 static class Loop extends Node {
4894 Node body;
4895 int countIndex; // local count index in matcher locals
4896 int beginIndex; // group beginning index
4897 int cmin, cmax;
4898 int posIndex;
4899 Loop(int countIndex, int beginIndex) {
4900 this.countIndex = countIndex;
4901 this.beginIndex = beginIndex;
4902 this.posIndex = -1;
4903 }
4904 boolean match(Matcher matcher, int i, CharSequence seq) {
4905 // Avoid infinite loop in zero-length case.
4906 if (i > matcher.locals[beginIndex]) {
4907 int count = matcher.locals[countIndex];
4908
4909 // This block is for before we reach the minimum
4910 // iterations required for the loop to match
4911 if (count < cmin) {
4912 matcher.locals[countIndex] = count + 1;
4913 boolean b = body.match(matcher, i, seq);
4914 // If match failed we must backtrack, so
4915 // the loop count should NOT be incremented
4916 if (!b)
4917 matcher.locals[countIndex] = count;
4918 // Return success or failure since we are under
4919 // minimum
4920 return b;
4921 }
4922 // This block is for after we have the minimum
4923 // iterations required for the loop to match
4924 if (count < cmax) {
4925 // Let's check if we have already tried and failed
4926 // at this starting position "i" in the past.
4927 // If yes, then just return false wihtout trying
4928 // again, to stop the exponential backtracking.
4929 if (posIndex != -1 &&
4930 matcher.localsPos[posIndex].contains(i)) {
4931 return next.match(matcher, i, seq);
4932 }
4933 matcher.locals[countIndex] = count + 1;
4934 boolean b = body.match(matcher, i, seq);
4935 // If match failed we must backtrack, so
4936 // the loop count should NOT be incremented
4937 if (b)
4938 return true;
4939 matcher.locals[countIndex] = count;
4940 // save the failed position
4941 if (posIndex != -1) {
4942 matcher.localsPos[posIndex].add(i);
4943 }
4944 }
4945 }
4946 return next.match(matcher, i, seq);
4947 }
4948 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4949 int save = matcher.locals[countIndex];
4950 boolean ret = false;
4951 if (posIndex != -1 && matcher.localsPos[posIndex] == null) {
4952 matcher.localsPos[posIndex] = new IntHashSet();
4953 }
4954 if (0 < cmin) {
4955 matcher.locals[countIndex] = 1;
4956 ret = body.match(matcher, i, seq);
4957 } else if (0 < cmax) {
4958 matcher.locals[countIndex] = 1;
4959 ret = body.match(matcher, i, seq);
4960 if (ret == false)
4961 ret = next.match(matcher, i, seq);
4962 } else {
4963 ret = next.match(matcher, i, seq);
4964 }
4965 matcher.locals[countIndex] = save;
4966 return ret;
4967 }
4968 boolean study(TreeInfo info) {
4969 info.maxValid = false;
4970 info.deterministic = false;
4971 return false;
4972 }
4973 }
4974
4975 /**
4976 * Handles the repetition count for a reluctant Curly. The matchInit
4977 * is called from the Prolog to save the index of where the group
4978 * beginning is stored. A zero length group check occurs in the
4979 * normal match but is skipped in the matchInit.
4980 */
4981 static final class LazyLoop extends Loop {
4982 LazyLoop(int countIndex, int beginIndex) {
4983 super(countIndex, beginIndex);
4984 }
4985 boolean match(Matcher matcher, int i, CharSequence seq) {
4986 // Check for zero length group
4987 if (i > matcher.locals[beginIndex]) {
4988 int count = matcher.locals[countIndex];
4989 if (count < cmin) {
4990 matcher.locals[countIndex] = count + 1;
4991 boolean result = body.match(matcher, i, seq);
4992 // If match failed we must backtrack, so
4993 // the loop count should NOT be incremented
4994 if (!result)
4995 matcher.locals[countIndex] = count;
4996 return result;
4997 }
4998 if (next.match(matcher, i, seq))
4999 return true;
5000 if (count < cmax) {
5001 matcher.locals[countIndex] = count + 1;
5002 boolean result = body.match(matcher, i, seq);
5003 // If match failed we must backtrack, so
5004 // the loop count should NOT be incremented
5005 if (!result)
5006 matcher.locals[countIndex] = count;
5007 return result;
5008 }
5009 return false;
5010 }
5011 return next.match(matcher, i, seq);
5012 }
5013 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
5014 int save = matcher.locals[countIndex];
5015 boolean ret = false;
5016 if (0 < cmin) {
5017 matcher.locals[countIndex] = 1;
5018 ret = body.match(matcher, i, seq);
5019 } else if (next.match(matcher, i, seq)) {
5020 ret = true;
5021 } else if (0 < cmax) {
5022 matcher.locals[countIndex] = 1;
5023 ret = body.match(matcher, i, seq);
5024 }
5025 matcher.locals[countIndex] = save;
5026 return ret;
5027 }
5028 boolean study(TreeInfo info) {
5029 info.maxValid = false;
5030 info.deterministic = false;
5031 return false;
5032 }
5033 }
5034
5035 /**
5036 * Refers to a group in the regular expression. Attempts to match
5037 * whatever the group referred to last matched.
5038 */
5039 static class BackRef extends Node {
5040 int groupIndex;
5041 BackRef(int groupCount) {
5042 super();
5043 groupIndex = groupCount + groupCount;
5044 }
5045 boolean match(Matcher matcher, int i, CharSequence seq) {
5046 int j = matcher.groups[groupIndex];
5047 int k = matcher.groups[groupIndex+1];
5048
5049 int groupSize = k - j;
5050 // If the referenced group didn't match, neither can this
5051 if (j < 0)
5052 return false;
5053
5054 // If there isn't enough input left no match
5055 if (i + groupSize > matcher.to) {
5056 matcher.hitEnd = true;
5057 return false;
5058 }
5059 // Check each new char to make sure it matches what the group
5060 // referenced matched last time around
5061 for (int index=0; index<groupSize; index++)
5062 if (seq.charAt(i+index) != seq.charAt(j+index))
5063 return false;
5064
5065 return next.match(matcher, i+groupSize, seq);
5066 }
5067 boolean study(TreeInfo info) {
5068 info.maxValid = false;
5069 return next.study(info);
5070 }
5071 }
5072
5073 static class CIBackRef extends Node {
5074 int groupIndex;
5075 boolean doUnicodeCase;
5076 CIBackRef(int groupCount, boolean doUnicodeCase) {
5077 super();
5078 groupIndex = groupCount + groupCount;
5079 this.doUnicodeCase = doUnicodeCase;
5080 }
5081 boolean match(Matcher matcher, int i, CharSequence seq) {
5082 int j = matcher.groups[groupIndex];
5083 int k = matcher.groups[groupIndex+1];
5084
5085 int groupSize = k - j;
5086
5087 // If the referenced group didn't match, neither can this
5088 if (j < 0)
5089 return false;
5090
5091 // If there isn't enough input left no match
5092 if (i + groupSize > matcher.to) {
5093 matcher.hitEnd = true;
5094 return false;
5095 }
5096
5097 // Check each new char to make sure it matches what the group
5098 // referenced matched last time around
5099 int x = i;
5100 for (int index=0; index<groupSize; index++) {
5101 int c1 = Character.codePointAt(seq, x);
5102 int c2 = Character.codePointAt(seq, j);
5103 if (c1 != c2) {
5104 if (doUnicodeCase) {
5105 int cc1 = Character.toUpperCase(c1);
5106 int cc2 = Character.toUpperCase(c2);
5107 if (cc1 != cc2 &&
5108 Character.toLowerCase(cc1) !=
5109 Character.toLowerCase(cc2))
5110 return false;
5111 } else {
5112 if (ASCII.toLower(c1) != ASCII.toLower(c2))
5113 return false;
5114 }
5115 }
5116 x += Character.charCount(c1);
5117 j += Character.charCount(c2);
5118 }
5119
5120 return next.match(matcher, i+groupSize, seq);
5121 }
5122 boolean study(TreeInfo info) {
5123 info.maxValid = false;
5124 return next.study(info);
5125 }
5126 }
5127
5128 /**
5129 * Searches until the next instance of its atom. This is useful for
5130 * finding the atom efficiently without passing an instance of it
5131 * (greedy problem) and without a lot of wasted search time (reluctant
5132 * problem).
5133 */
5134 static final class First extends Node {
5135 Node atom;
5136 First(Node node) {
5137 this.atom = BnM.optimize(node);
5138 }
5139 boolean match(Matcher matcher, int i, CharSequence seq) {
5140 if (atom instanceof BnM) {
5141 return atom.match(matcher, i, seq)
5142 && next.match(matcher, matcher.last, seq);
5143 }
5144 for (;;) {
5145 if (i > matcher.to) {
5146 matcher.hitEnd = true;
5147 return false;
5148 }
5149 if (atom.match(matcher, i, seq)) {
5150 return next.match(matcher, matcher.last, seq);
5151 }
5152 i += countChars(seq, i, 1);
5153 matcher.first++;
5154 }
5155 }
5156 boolean study(TreeInfo info) {
5157 atom.study(info);
5158 info.maxValid = false;
5159 info.deterministic = false;
5160 return next.study(info);
5161 }
5162 }
5163
5164 static final class Conditional extends Node {
5165 Node cond, yes, not;
5166 Conditional(Node cond, Node yes, Node not) {
5167 this.cond = cond;
5168 this.yes = yes;
5169 this.not = not;
5170 }
5171 boolean match(Matcher matcher, int i, CharSequence seq) {
5172 if (cond.match(matcher, i, seq)) {
5173 return yes.match(matcher, i, seq);
5174 } else {
5175 return not.match(matcher, i, seq);
5176 }
5177 }
5178 boolean study(TreeInfo info) {
5179 int minL = info.minLength;
5180 int maxL = info.maxLength;
5181 boolean maxV = info.maxValid;
5182 info.reset();
5183 yes.study(info);
5184
5185 int minL2 = info.minLength;
5186 int maxL2 = info.maxLength;
5187 boolean maxV2 = info.maxValid;
5188 info.reset();
5189 not.study(info);
5190
5191 info.minLength = minL + Math.min(minL2, info.minLength);
5192 info.maxLength = maxL + Math.max(maxL2, info.maxLength);
5193 info.maxValid = (maxV & maxV2 & info.maxValid);
5194 info.deterministic = false;
5195 return next.study(info);
5196 }
5197 }
5198
5199 /**
5200 * Zero width positive lookahead.
5201 */
5202 static final class Pos extends Node {
5203 Node cond;
5204 Pos(Node cond) {
5205 this.cond = cond;
5206 }
5207 boolean match(Matcher matcher, int i, CharSequence seq) {
5208 int savedTo = matcher.to;
5209 boolean conditionMatched = false;
5210
5211 // Relax transparent region boundaries for lookahead
5212 if (matcher.transparentBounds)
5213 matcher.to = matcher.getTextLength();
5214 try {
5215 conditionMatched = cond.match(matcher, i, seq);
5216 } finally {
5217 // Reinstate region boundaries
5218 matcher.to = savedTo;
5219 }
5220 return conditionMatched && next.match(matcher, i, seq);
5221 }
5222 }
5223
5224 /**
5225 * Zero width negative lookahead.
5226 */
5227 static final class Neg extends Node {
5228 Node cond;
5229 Neg(Node cond) {
5230 this.cond = cond;
5231 }
5232 boolean match(Matcher matcher, int i, CharSequence seq) {
5233 int savedTo = matcher.to;
5234 boolean conditionMatched = false;
5235
5236 // Relax transparent region boundaries for lookahead
5237 if (matcher.transparentBounds)
5238 matcher.to = matcher.getTextLength();
5239 try {
5240 if (i < matcher.to) {
5241 conditionMatched = !cond.match(matcher, i, seq);
5242 } else {
5243 // If a negative lookahead succeeds then more input
5244 // could cause it to fail!
5245 matcher.requireEnd = true;
5246 conditionMatched = !cond.match(matcher, i, seq);
5247 }
5248 } finally {
5249 // Reinstate region boundaries
5250 matcher.to = savedTo;
5251 }
5252 return conditionMatched && next.match(matcher, i, seq);
5253 }
5254 }
5255
5256 /**
5257 * For use with lookbehinds; matches the position where the lookbehind
5258 * was encountered.
5259 */
5260 static Node lookbehindEnd = new Node() {
5261 boolean match(Matcher matcher, int i, CharSequence seq) {
5262 return i == matcher.lookbehindTo;
5263 }
5264 };
5265
5266 /**
5267 * Zero width positive lookbehind.
5268 */
5269 static class Behind extends Node {
5270 Node cond;
5271 int rmax, rmin;
5272 Behind(Node cond, int rmax, int rmin) {
5273 this.cond = cond;
5274 this.rmax = rmax;
5275 this.rmin = rmin;
5276 }
5277
5278 boolean match(Matcher matcher, int i, CharSequence seq) {
5279 int savedFrom = matcher.from;
5280 boolean conditionMatched = false;
5281 int startIndex = (!matcher.transparentBounds) ?
5282 matcher.from : 0;
5283 int from = Math.max(i - rmax, 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 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5291 conditionMatched = cond.match(matcher, j, seq);
5292 }
5293 matcher.from = savedFrom;
5294 matcher.lookbehindTo = savedLBT;
5295 return conditionMatched && next.match(matcher, i, seq);
5296 }
5297 }
5298
5299 /**
5300 * Zero width positive lookbehind, including supplementary
5301 * characters or unpaired surrogates.
5302 */
5303 static final class BehindS extends Behind {
5304 BehindS(Node cond, int rmax, int rmin) {
5305 super(cond, rmax, rmin);
5306 }
5307 boolean match(Matcher matcher, int i, CharSequence seq) {
5308 int rmaxChars = countChars(seq, i, -rmax);
5309 int rminChars = countChars(seq, i, -rmin);
5310 int savedFrom = matcher.from;
5311 int startIndex = (!matcher.transparentBounds) ?
5312 matcher.from : 0;
5313 boolean conditionMatched = false;
5314 int from = Math.max(i - rmaxChars, startIndex);
5315 // Set end boundary
5316 int savedLBT = matcher.lookbehindTo;
5317 matcher.lookbehindTo = i;
5318 // Relax transparent region boundaries for lookbehind
5319 if (matcher.transparentBounds)
5320 matcher.from = 0;
5321
5322 for (int j = i - rminChars;
5323 !conditionMatched && j >= from;
5324 j -= j>from ? countChars(seq, j, -1) : 1) {
5325 conditionMatched = cond.match(matcher, j, seq);
5326 }
5327 matcher.from = savedFrom;
5328 matcher.lookbehindTo = savedLBT;
5329 return conditionMatched && next.match(matcher, i, seq);
5330 }
5331 }
5332
5333 /**
5334 * Zero width negative lookbehind.
5335 */
5336 static class NotBehind extends Node {
5337 Node cond;
5338 int rmax, rmin;
5339 NotBehind(Node cond, int rmax, int rmin) {
5340 this.cond = cond;
5341 this.rmax = rmax;
5342 this.rmin = rmin;
5343 }
5344
5345 boolean match(Matcher matcher, int i, CharSequence seq) {
5346 int savedLBT = matcher.lookbehindTo;
5347 int savedFrom = matcher.from;
5348 boolean conditionMatched = false;
5349 int startIndex = (!matcher.transparentBounds) ?
5350 matcher.from : 0;
5351 int from = Math.max(i - rmax, 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 - rmin; !conditionMatched && j >= from; j--) {
5357 conditionMatched = cond.match(matcher, j, seq);
5358 }
5359 // Reinstate region boundaries
5360 matcher.from = savedFrom;
5361 matcher.lookbehindTo = savedLBT;
5362 return !conditionMatched && next.match(matcher, i, seq);
5363 }
5364 }
5365
5366 /**
5367 * Zero width negative lookbehind, including supplementary
5368 * characters or unpaired surrogates.
5369 */
5370 static final class NotBehindS extends NotBehind {
5371 NotBehindS(Node cond, int rmax, int rmin) {
5372 super(cond, rmax, rmin);
5373 }
5374 boolean match(Matcher matcher, int i, CharSequence seq) {
5375 int rmaxChars = countChars(seq, i, -rmax);
5376 int rminChars = countChars(seq, i, -rmin);
5377 int savedFrom = matcher.from;
5378 int savedLBT = matcher.lookbehindTo;
5379 boolean conditionMatched = false;
5380 int startIndex = (!matcher.transparentBounds) ?
5381 matcher.from : 0;
5382 int from = Math.max(i - rmaxChars, startIndex);
5383 matcher.lookbehindTo = i;
5384 // Relax transparent region boundaries for lookbehind
5385 if (matcher.transparentBounds)
5386 matcher.from = 0;
5387 for (int j = i - rminChars;
5388 !conditionMatched && j >= from;
5389 j -= j>from ? countChars(seq, j, -1) : 1) {
5390 conditionMatched = cond.match(matcher, j, seq);
5391 }
5392 //Reinstate region boundaries
5393 matcher.from = savedFrom;
5394 matcher.lookbehindTo = savedLBT;
5395 return !conditionMatched && next.match(matcher, i, seq);
5396 }
5397 }
5398
5399 /**
5400 * Handles word boundaries. Includes a field to allow this one class to
5401 * deal with the different types of word boundaries we can match. The word
5402 * characters include underscores, letters, and digits. Non spacing marks
5403 * can are also part of a word if they have a base character, otherwise
5404 * they are ignored for purposes of finding word boundaries.
5405 */
5406 static final class Bound extends Node {
5407 static int LEFT = 0x1;
5408 static int RIGHT= 0x2;
5409 static int BOTH = 0x3;
5410 static int NONE = 0x4;
5411 int type;
5412 boolean useUWORD;
5413 Bound(int n, boolean useUWORD) {
5414 type = n;
5415 this.useUWORD = useUWORD;
5416 }
5417
5418 boolean isWord(int ch) {
5419 return useUWORD ? CharPredicates.WORD().is(ch)
5420 : (ch == '_' || Character.isLetterOrDigit(ch));
5421 }
5422
5423 int check(Matcher matcher, int i, CharSequence seq) {
5424 int ch;
5425 boolean left = false;
5426 int startIndex = matcher.from;
5427 int endIndex = matcher.to;
5428 if (matcher.transparentBounds) {
5429 startIndex = 0;
5430 endIndex = matcher.getTextLength();
5431 }
5432 if (i > startIndex) {
5433 ch = Character.codePointBefore(seq, i);
5434 left = (isWord(ch) ||
5435 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5436 && hasBaseCharacter(matcher, i-1, seq)));
5437 }
5438 boolean right = false;
5439 if (i < endIndex) {
5440 ch = Character.codePointAt(seq, i);
5441 right = (isWord(ch) ||
5442 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5443 && hasBaseCharacter(matcher, i, seq)));
5444 } else {
5445 // Tried to access char past the end
5446 matcher.hitEnd = true;
5447 // The addition of another char could wreck a boundary
5448 matcher.requireEnd = true;
5449 }
5450 return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE);
5451 }
5452 boolean match(Matcher matcher, int i, CharSequence seq) {
5453 return (check(matcher, i, seq) & type) > 0
5454 && next.match(matcher, i, seq);
5455 }
5456 }
5457
5458 /**
5459 * Non spacing marks only count as word characters in bounds calculations
5460 * if they have a base character.
5461 */
5462 private static boolean hasBaseCharacter(Matcher matcher, int i,
5463 CharSequence seq)
5464 {
5465 int start = (!matcher.transparentBounds) ?
5466 matcher.from : 0;
5467 for (int x=i; x >= start; x--) {
5468 int ch = Character.codePointAt(seq, x);
5469 if (Character.isLetterOrDigit(ch))
5470 return true;
5471 if (Character.getType(ch) == Character.NON_SPACING_MARK)
5472 continue;
5473 return false;
5474 }
5475 return false;
5476 }
5477
5478 /**
5479 * Attempts to match a slice in the input using the Boyer-Moore string
5480 * matching algorithm. The algorithm is based on the idea that the
5481 * pattern can be shifted farther ahead in the search text if it is
5482 * matched right to left.
5483 * <p>
5484 * The pattern is compared to the input one character at a time, from
5485 * the rightmost character in the pattern to the left. If the characters
5486 * all match the pattern has been found. If a character does not match,
5487 * the pattern is shifted right a distance that is the maximum of two
5488 * functions, the bad character shift and the good suffix shift. This
5489 * shift moves the attempted match position through the input more
5490 * quickly than a naive one position at a time check.
5491 * <p>
5492 * The bad character shift is based on the character from the text that
5493 * did not match. If the character does not appear in the pattern, the
5494 * pattern can be shifted completely beyond the bad character. If the
5495 * character does occur in the pattern, the pattern can be shifted to
5496 * line the pattern up with the next occurrence of that character.
5497 * <p>
5498 * The good suffix shift is based on the idea that some subset on the right
5499 * side of the pattern has matched. When a bad character is found, the
5500 * pattern can be shifted right by the pattern length if the subset does
5501 * not occur again in pattern, or by the amount of distance to the
5502 * next occurrence of the subset in the pattern.
5503 *
5504 * Boyer-Moore search methods adapted from code by Amy Yu.
5505 */
5506 static class BnM extends Node {
5507 int[] buffer;
5508 int[] lastOcc;
5509 int[] optoSft;
5510
5511 /**
5512 * Pre calculates arrays needed to generate the bad character
5513 * shift and the good suffix shift. Only the last seven bits
5514 * are used to see if chars match; This keeps the tables small
5515 * and covers the heavily used ASCII range, but occasionally
5516 * results in an aliased match for the bad character shift.
5517 */
5518 static Node optimize(Node node) {
5519 if (!(node instanceof Slice)) {
5520 return node;
5521 }
5522
5523 int[] src = ((Slice) node).buffer;
5524 int patternLength = src.length;
5525 // The BM algorithm requires a bit of overhead;
5526 // If the pattern is short don't use it, since
5527 // a shift larger than the pattern length cannot
5528 // be used anyway.
5529 if (patternLength < 4) {
5530 return node;
5531 }
5532 int i, j, k;
5533 int[] lastOcc = new int[128];
5534 int[] optoSft = new int[patternLength];
5535 // Precalculate part of the bad character shift
5536 // It is a table for where in the pattern each
5537 // lower 7-bit value occurs
5538 for (i = 0; i < patternLength; i++) {
5539 lastOcc[src[i]&0x7F] = i + 1;
5540 }
5541 // Precalculate the good suffix shift
5542 // i is the shift amount being considered
5543 NEXT: for (i = patternLength; i > 0; i--) {
5544 // j is the beginning index of suffix being considered
5545 for (j = patternLength - 1; j >= i; j--) {
5546 // Testing for good suffix
5547 if (src[j] == src[j-i]) {
5548 // src[j..len] is a good suffix
5549 optoSft[j-1] = i;
5550 } else {
5551 // No match. The array has already been
5552 // filled up with correct values before.
5553 continue NEXT;
5554 }
5555 }
5556 // This fills up the remaining of optoSft
5557 // any suffix can not have larger shift amount
5558 // then its sub-suffix. Why???
5559 while (j > 0) {
5560 optoSft[--j] = i;
5561 }
5562 }
5563 // Set the guard value because of unicode compression
5564 optoSft[patternLength-1] = 1;
5565 if (node instanceof SliceS)
5566 return new BnMS(src, lastOcc, optoSft, node.next);
5567 return new BnM(src, lastOcc, optoSft, node.next);
5568 }
5569 BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5570 this.buffer = src;
5571 this.lastOcc = lastOcc;
5572 this.optoSft = optoSft;
5573 this.next = next;
5574 }
5575 boolean match(Matcher matcher, int i, CharSequence seq) {
5576 int[] src = buffer;
5577 int patternLength = src.length;
5578 int last = matcher.to - patternLength;
5579
5580 // Loop over all possible match positions in text
5581 NEXT: while (i <= last) {
5582 // Loop over pattern from right to left
5583 for (int j = patternLength - 1; j >= 0; j--) {
5584 int ch = seq.charAt(i+j);
5585 if (ch != src[j]) {
5586 // Shift search to the right by the maximum of the
5587 // bad character shift and the good suffix shift
5588 i += Math.max(j + 1 - lastOcc[ch&0x7F], optoSft[j]);
5589 continue NEXT;
5590 }
5591 }
5592 // Entire pattern matched starting at i
5593 matcher.first = i;
5594 boolean ret = next.match(matcher, i + patternLength, seq);
5595 if (ret) {
5596 matcher.first = i;
5597 matcher.groups[0] = matcher.first;
5598 matcher.groups[1] = matcher.last;
5599 return true;
5600 }
5601 i++;
5602 }
5603 // BnM is only used as the leading node in the unanchored case,
5604 // and it replaced its Start() which always searches to the end
5605 // if it doesn't find what it's looking for, so hitEnd is true.
5606 matcher.hitEnd = true;
5607 return false;
5608 }
5609 boolean study(TreeInfo info) {
5610 info.minLength += buffer.length;
5611 info.maxValid = false;
5612 return next.study(info);
5613 }
5614 }
5615
5616 /**
5617 * Supplementary support version of BnM(). Unpaired surrogates are
5618 * also handled by this class.
5619 */
5620 static final class BnMS extends BnM {
5621 int lengthInChars;
5622
5623 BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5624 super(src, lastOcc, optoSft, next);
5625 for (int cp : buffer) {
5626 lengthInChars += Character.charCount(cp);
5627 }
5628 }
5629 boolean match(Matcher matcher, int i, CharSequence seq) {
5630 int[] src = buffer;
5631 int patternLength = src.length;
5632 int last = matcher.to - lengthInChars;
5633
5634 // Loop over all possible match positions in text
5635 NEXT: while (i <= last) {
5636 // Loop over pattern from right to left
5637 int ch;
5638 for (int j = countChars(seq, i, patternLength), x = patternLength - 1;
5639 j > 0; j -= Character.charCount(ch), x--) {
5640 ch = Character.codePointBefore(seq, i+j);
5641 if (ch != src[x]) {
5642 // Shift search to the right by the maximum of the
5643 // bad character shift and the good suffix shift
5644 int n = Math.max(x + 1 - lastOcc[ch&0x7F], optoSft[x]);
5645 i += countChars(seq, i, n);
5646 continue NEXT;
5647 }
5648 }
5649 // Entire pattern matched starting at i
5650 matcher.first = i;
5651 boolean ret = next.match(matcher, i + lengthInChars, seq);
5652 if (ret) {
5653 matcher.first = i;
5654 matcher.groups[0] = matcher.first;
5655 matcher.groups[1] = matcher.last;
5656 return true;
5657 }
5658 i += countChars(seq, i, 1);
5659 }
5660 matcher.hitEnd = true;
5661 return false;
5662 }
5663 }
5664
5665 @FunctionalInterface
5666 static interface CharPredicate {
5667 boolean is(int ch);
5668
5669 default CharPredicate and(CharPredicate p) {
5670 return ch -> is(ch) && p.is(ch);
5671 }
5672 default CharPredicate union(CharPredicate p) {
5673 return ch -> is(ch) || p.is(ch);
5674 }
5675 default CharPredicate union(CharPredicate p1,
5676 CharPredicate p2 ) {
5677 return ch -> is(ch) || p1.is(ch) || p2.is(ch);
5678 }
5679 default CharPredicate negate() {
5680 return ch -> !is(ch);
5681 }
5682 }
5683
5684 static interface BmpCharPredicate extends CharPredicate {
5685
5686 default CharPredicate and(CharPredicate p) {
5687 if(p instanceof BmpCharPredicate)
5688 return (BmpCharPredicate)(ch -> is(ch) && p.is(ch));
5689 return ch -> is(ch) && p.is(ch);
5690 }
5691 default CharPredicate union(CharPredicate p) {
5692 if (p instanceof BmpCharPredicate)
5693 return (BmpCharPredicate)(ch -> is(ch) || p.is(ch));
5694 return ch -> is(ch) || p.is(ch);
5695 }
5696 static CharPredicate union(CharPredicate... predicates) {
5697 CharPredicate cp = ch -> {
5698 for (CharPredicate p : predicates) {
5699 if (!p.is(ch))
5700 return false;
5701 }
5702 return true;
5703 };
5704 for (CharPredicate p : predicates) {
5705 if (! (p instanceof BmpCharPredicate))
5706 return cp;
5707 }
5708 return (BmpCharPredicate)cp;
5709 }
5710 }
5711
5712 /**
5713 * matches a Perl vertical whitespace
5714 */
5715 static BmpCharPredicate VertWS() {
5716 return cp -> (cp >= 0x0A && cp <= 0x0D) ||
5717 cp == 0x85 || cp == 0x2028 || cp == 0x2029;
5718 }
5719
5720 /**
5721 * matches a Perl horizontal whitespace
5722 */
5723 static BmpCharPredicate HorizWS() {
5724 return cp ->
5725 cp == 0x09 || cp == 0x20 || cp == 0xa0 || cp == 0x1680 ||
5726 cp == 0x180e || cp >= 0x2000 && cp <= 0x200a || cp == 0x202f ||
5727 cp == 0x205f || cp == 0x3000;
5728 }
5729
5730 /**
5731 * for the Unicode category ALL and the dot metacharacter when
5732 * in dotall mode.
5733 */
5734 static CharPredicate ALL() {
5735 return ch -> true;
5736 }
5737
5738 /**
5739 * for the dot metacharacter when dotall is not enabled.
5740 */
5741 static CharPredicate DOT() {
5742 return ch ->
5743 (ch != '\n' && ch != '\r'
5744 && (ch|1) != '\u2029'
5745 && ch != '\u0085');
5746 }
5747
5748 /**
5749 * the dot metacharacter when dotall is not enabled but UNIX_LINES is enabled.
5750 */
5751 static CharPredicate UNIXDOT() {
5752 return ch -> ch != '\n';
5753 }
5754
5755 /**
5756 * Indicate that matches a Supplementary Unicode character
5757 */
5758 static CharPredicate SingleS(int c) {
5759 return ch -> ch == c;
5760 }
5761
5762 /**
5763 * A bmp/optimized predicate of single
5764 */
5765 static BmpCharPredicate Single(int c) {
5766 return ch -> ch == c;
5767 }
5768
5769 /**
5770 * Case insensitive matches a given BMP character
5771 */
5772 static BmpCharPredicate SingleI(int lower, int upper) {
5773 return ch -> ch == lower || ch == upper;
5774 }
5775
5776 /**
5777 * Unicode case insensitive matches a given Unicode character
5778 */
5779 static CharPredicate SingleU(int lower) {
5780 return ch -> lower == ch ||
5781 lower == Character.toLowerCase(Character.toUpperCase(ch));
5782 }
5783
5784 private static boolean inRange(int lower, int ch, int upper) {
5785 return lower <= ch && ch <= upper;
5786 }
5787
5788 /**
5789 * Charactrs within a explicit value range
5790 */
5791 static CharPredicate Range(int lower, int upper) {
5792 if (upper < Character.MIN_HIGH_SURROGATE ||
5793 lower > Character.MAX_HIGH_SURROGATE &&
5794 upper < Character.MIN_SUPPLEMENTARY_CODE_POINT)
5795 return (BmpCharPredicate)(ch -> inRange(lower, ch, upper));
5796 return ch -> inRange(lower, ch, upper);
5797 }
5798
5799 /**
5800 * Charactrs within a explicit value range in a case insensitive manner.
5801 */
5802 static CharPredicate CIRange(int lower, int upper) {
5803 return ch -> inRange(lower, ch, upper) ||
5804 ASCII.isAscii(ch) &&
5805 (inRange(lower, ASCII.toUpper(ch), upper) ||
5806 inRange(lower, ASCII.toLower(ch), upper));
5807 }
5808
5809 static CharPredicate CIRangeU(int lower, int upper) {
5810 return ch -> {
5811 if (inRange(lower, ch, upper))
5812 return true;
5813 int up = Character.toUpperCase(ch);
5814 return inRange(lower, up, upper) ||
5815 inRange(lower, Character.toLowerCase(up), upper);
5816 };
5817 }
5818
5819 /**
5820 * This must be the very first initializer.
5821 */
5822 static final Node accept = new Node();
5823
5824 static final Node lastAccept = new LastNode();
5825
5826 /**
5827 * Creates a predicate that tests if this pattern is found in a given input
5828 * string.
5829 *
5830 * @apiNote
5831 * This method creates a predicate that behaves as if it creates a matcher
5832 * from the input sequence and then calls {@code find}, for example a
5833 * predicate of the form:
5834 * <pre>{@code
5835 * s -> matcher(s).find();
5836 * }</pre>
5837 *
5838 * @return The predicate which can be used for finding a match on a
5839 * subsequence of a string
5840 * @since 1.8
5841 * @see Matcher#find
5842 */
5843 public Predicate<String> asPredicate() {
5844 return s -> matcher(s).find();
5845 }
5846
5847 /**
5848 * Creates a predicate that tests if this pattern matches a given input string.
5849 *
5850 * @apiNote
5851 * This method creates a predicate that behaves as if it creates a matcher
5852 * from the input sequence and then calls {@code matches}, for example a
5853 * predicate of the form:
5854 * <pre>{@code
5855 * s -> matcher(s).matches();
5856 * }</pre>
5857 *
5858 * @return The predicate which can be used for matching an input string
5859 * against this pattern.
5860 * @since 11
5861 * @see Matcher#matches
5862 */
5863 public Predicate<String> asMatchPredicate() {
5864 return s -> matcher(s).matches();
5865 }
5866
5867 /**
5868 * Creates a stream from the given input sequence around matches of this
5869 * pattern.
5870 *
5871 * <p> The stream returned by this method contains each substring of the
5872 * input sequence that is terminated by another subsequence that matches
5873 * this pattern or is terminated by the end of the input sequence. The
5874 * substrings in the stream are in the order in which they occur in the
5875 * input. Trailing empty strings will be discarded and not encountered in
5876 * the stream.
5877 *
5878 * <p> If this pattern does not match any subsequence of the input then
5879 * the resulting stream has just one element, namely the input sequence in
5880 * string form.
5881 *
5882 * <p> When there is a positive-width match at the beginning of the input
5883 * sequence then an empty leading substring is included at the beginning
5884 * of the stream. A zero-width match at the beginning however never produces
5885 * such empty leading substring.
5886 *
5887 * <p> If the input sequence is mutable, it must remain constant during the
5888 * execution of the terminal stream operation. Otherwise, the result of the
5889 * terminal stream operation is undefined.
5890 *
5891 * @param input
5892 * The character sequence to be split
5893 *
5894 * @return The stream of strings computed by splitting the input
5895 * around matches of this pattern
5896 * @see #split(CharSequence)
5897 * @since 1.8
5898 */
5899 public Stream<String> splitAsStream(final CharSequence input) {
5900 class MatcherIterator implements Iterator<String> {
5901 private Matcher matcher;
5902 // The start position of the next sub-sequence of input
5903 // when current == input.length there are no more elements
5904 private int current;
5905 // null if the next element, if any, needs to obtained
5906 private String nextElement;
5907 // > 0 if there are N next empty elements
5908 private int emptyElementCount;
5909
5910 public String next() {
5911 if (!hasNext())
5912 throw new NoSuchElementException();
5913
5914 if (emptyElementCount == 0) {
5915 String n = nextElement;
5916 nextElement = null;
5917 return n;
5918 } else {
5919 emptyElementCount--;
5920 return "";
5921 }
5922 }
5923
5924 public boolean hasNext() {
5925 if (matcher == null) {
5926 matcher = matcher(input);
5927 // If the input is an empty string then the result can only be a
5928 // stream of the input. Induce that by setting the empty
5929 // element count to 1
5930 emptyElementCount = input.length() == 0 ? 1 : 0;
5931 }
5932 if (nextElement != null || emptyElementCount > 0)
5933 return true;
5934
5935 if (current == input.length())
5936 return false;
5937
5938 // Consume the next matching element
5939 // Count sequence of matching empty elements
5940 while (matcher.find()) {
5941 nextElement = input.subSequence(current, matcher.start()).toString();
5942 current = matcher.end();
5943 if (!nextElement.isEmpty()) {
5944 return true;
5945 } else if (current > 0) { // no empty leading substring for zero-width
5946 // match at the beginning of the input
5947 emptyElementCount++;
5948 }
5949 }
5950
5951 // Consume last matching element
5952 nextElement = input.subSequence(current, input.length()).toString();
5953 current = input.length();
5954 if (!nextElement.isEmpty()) {
5955 return true;
5956 } else {
5957 // Ignore a terminal sequence of matching empty elements
5958 emptyElementCount = 0;
5959 nextElement = null;
5960 return false;
5961 }
5962 }
5963 }
5964 return StreamSupport.stream(Spliterators.spliteratorUnknownSize(
5965 new MatcherIterator(), Spliterator.ORDERED | Spliterator.NONNULL), false);
5966 }
5967 }