1 /*
2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
3 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
4 *
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24 */
25
26 package java.util.regex;
27
28 import java.text.Normalizer;
29 import java.text.Normalizer.Form;
30 import java.util.Locale;
31 import java.util.Iterator;
32 import java.util.Map;
33 import java.util.ArrayList;
34 import java.util.HashMap;
35 import java.util.LinkedHashSet;
36 import java.util.List;
37 import java.util.Set;
38 import java.util.Arrays;
39 import java.util.NoSuchElementException;
40 import java.util.Spliterator;
41 import java.util.Spliterators;
42 import java.util.function.Predicate;
43 import java.util.stream.Stream;
44 import java.util.stream.StreamSupport;
45
46
47 /**
48 * A compiled representation of a regular expression.
49 *
50 * <p> A regular expression, specified as a string, must first be compiled into
51 * an instance of this class. The resulting pattern can then be used to create
52 * a {@link Matcher} object that can match arbitrary {@linkplain
53 * java.lang.CharSequence character sequences} against the regular
54 * expression. All of the state involved in performing a match resides in the
55 * matcher, so many matchers can share the same pattern.
56 *
57 * <p> A typical invocation sequence is thus
58 *
59 * <blockquote><pre>
60 * Pattern p = Pattern.{@link #compile compile}("a*b");
61 * Matcher m = p.{@link #matcher matcher}("aaaaab");
62 * boolean b = m.{@link Matcher#matches matches}();</pre></blockquote>
63 *
64 * <p> A {@link #matches matches} method is defined by this class as a
65 * convenience for when a regular expression is used just once. This method
66 * compiles an expression and matches an input sequence against it in a single
67 * invocation. The statement
68 *
69 * <blockquote><pre>
70 * boolean b = Pattern.matches("a*b", "aaaaab");</pre></blockquote>
71 *
72 * is equivalent to the three statements above, though for repeated matches it
73 * is less efficient since it does not allow the compiled pattern to be reused.
74 *
75 * <p> Instances of this class are immutable and are safe for use by multiple
76 * concurrent threads. Instances of the {@link Matcher} class are not safe for
77 * such use.
78 *
79 *
80 * <h3><a id="sum">Summary of regular-expression constructs</a></h3>
81 *
82 * <table class="borderless">
83 * <caption style="display:none">Regular expression constructs, and what they match</caption>
84 * <thead style="text-align:left">
85 * <tr>
86 * <th id="construct">Construct</th>
87 * <th id="matches">Matches</th>
88 * </tr>
89 * </thead>
90 * <tbody style="text-align:left">
91 *
92 * <tr><th colspan="2" style="padding-top:20px" id="characters">Characters</th></tr>
93 *
94 * <tr><th style="vertical-align:top; font-weight: normal" id="x"><i>x</i></th>
95 * <td headers="matches characters x">The character <i>x</i></td></tr>
96 * <tr><th style="vertical-align:top; font-weight: normal" id="backslash">{@code \\}</th>
97 * <td headers="matches characters backslash">The backslash character</td></tr>
98 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_n">{@code \0}<i>n</i></th>
99 * <td headers="matches characters octal_n">The character with octal value {@code 0}<i>n</i>
100 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
101 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nn">{@code \0}<i>nn</i></th>
102 * <td headers="matches characters octal_nn">The character with octal value {@code 0}<i>nn</i>
103 * (0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
104 * <tr><th style="vertical-align:top; font-weight: normal" id="octal_nnn">{@code \0}<i>mnn</i></th>
105 * <td headers="matches characters octal_nnn">The character with octal value {@code 0}<i>mnn</i>
106 * (0 {@code <=} <i>m</i> {@code <=} 3,
107 * 0 {@code <=} <i>n</i> {@code <=} 7)</td></tr>
108 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hh">{@code \x}<i>hh</i></th>
109 * <td headers="matches characters hex_hh">The character with hexadecimal value {@code 0x}<i>hh</i></td></tr>
110 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_hhhh"><code>\u</code><i>hhhh</i></th>
111 * <td headers="matches characters hex_hhhh">The character with hexadecimal value {@code 0x}<i>hhhh</i></td></tr>
112 * <tr><th style="vertical-align:top; font-weight: normal" id="hex_h_h"><code>\x</code><i>{h...h}</i></th>
113 * <td headers="matches characters hex_h_h">The character with hexadecimal value {@code 0x}<i>h...h</i>
114 * ({@link java.lang.Character#MIN_CODE_POINT Character.MIN_CODE_POINT}
115 * <= {@code 0x}<i>h...h</i> <=
116 * {@link java.lang.Character#MAX_CODE_POINT Character.MAX_CODE_POINT})</td></tr>
117 * <tr><th style="vertical-align:top; font-weight: normal" id="unicode_name"><code>\N{</code><i>name</i><code>}</code></th>
118 * <td headers="matches characters unicode_name">The character with Unicode character name <i>‘name‘</i></td></tr>
119 * <tr><th style="vertical-align:top; font-weight:normal" id="tab">{@code \t}</th>
120 * <td headers="matches characters tab">The tab character (<code>‘\u0009‘</code>)</td></tr>
121 * <tr><th style="vertical-align:top; font-weight:normal" id="newline">{@code \n}</th>
122 * <td headers="matches characters newline">The newline (line feed) character (<code>‘\u000A‘</code>)</td></tr>
123 * <tr><th style="vertical-align:top; font-weight:normal" id="return">{@code \r}</th>
124 * <td headers="matches characters return">The carriage-return character (<code>‘\u000D‘</code>)</td></tr>
125 * <tr><th style="vertical-align:top; font-weight:normal" id="form_feed">{@code \f}</th>
126 * <td headers="matches characters form_feed">The form-feed character (<code>‘\u000C‘</code>)</td></tr>
127 * <tr><th style="vertical-align:top; font-weight:normal" id="bell">{@code \a}</th>
128 * <td headers="matches characters bell">The alert (bell) character (<code>‘\u0007‘</code>)</td></tr>
129 * <tr><th style="vertical-align:top; font-weight:normal" id="escape">{@code \e}</th>
130 * <td headers="matches characters escape">The escape character (<code>‘\u001B‘</code>)</td></tr>
131 * <tr><th style="vertical-align:top; font-weight:normal" id="ctrl_x">{@code \c}<i>x</i></th>
132 * <td headers="matches characters ctrl_x">The control character corresponding to <i>x</i></td></tr>
133 *
134 * <tr><th colspan="2" style="padding-top:20px" id="classes">Character classes</th></tr>
135 *
136 * <tr><th style="vertical-align:top; font-weight:normal" id="simple">{@code [abc]}</th>
137 * <td headers="matches classes simple">{@code a}, {@code b}, or {@code c} (simple class)</td></tr>
138 * <tr><th style="vertical-align:top; font-weight:normal" id="negation">{@code [^abc]}</th>
139 * <td headers="matches classes negation">Any character except {@code a}, {@code b}, or {@code c} (negation)</td></tr>
140 * <tr><th style="vertical-align:top; font-weight:normal" id="range">{@code [a-zA-Z]}</th>
141 * <td headers="matches classes range">{@code a} through {@code z}
142 * or {@code A} through {@code Z}, inclusive (range)</td></tr>
143 * <tr><th style="vertical-align:top; font-weight:normal" id="union">{@code [a-d[m-p]]}</th>
144 * <td headers="matches classes union">{@code a} through {@code d},
145 * or {@code m} through {@code p}: {@code [a-dm-p]} (union)</td></tr>
146 * <tr><th style="vertical-align:top; font-weight:normal" id="intersection">{@code [a-z&&[def]]}</th>
147 * <td headers="matches classes intersection">{@code d}, {@code e}, or {@code f} (intersection)</tr>
148 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction1">{@code [a-z&&[^bc]]}</th>
149 * <td headers="matches classes subtraction1">{@code a} through {@code z},
150 * except for {@code b} and {@code c}: {@code [ad-z]} (subtraction)</td></tr>
151 * <tr><th style="vertical-align:top; font-weight:normal" id="subtraction2">{@code [a-z&&[^m-p]]}</th>
152 * <td headers="matches classes subtraction2">{@code a} through {@code z},
153 * and not {@code m} through {@code p}: {@code [a-lq-z]}(subtraction)</td></tr>
154 *
155 * <tr><th colspan="2" style="padding-top:20px" id="predef">Predefined character classes</th></tr>
156 *
157 * <tr><th style="vertical-align:top; font-weight:normal" id="any">{@code .}</th>
158 * <td headers="matches predef any">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
159 * <tr><th style="vertical-align:top; font-weight:normal" id="digit">{@code \d}</th>
160 * <td headers="matches predef digit">A digit: {@code [0-9]}</td></tr>
161 * <tr><th style="vertical-align:top; font-weight:normal" id="non_digit">{@code \D}</th>
162 * <td headers="matches predef non_digit">A non-digit: {@code [^0-9]}</td></tr>
163 * <tr><th style="vertical-align:top; font-weight:normal" id="horiz_white">{@code \h}</th>
164 * <td headers="matches predef horiz_white">A horizontal whitespace character:
165 * <code>[ \t\xA0\u1680\u180e\u2000-\u200a\u202f\u205f\u3000]</code></td></tr>
166 * <tr><th style="vertical-align:top; font-weight:normal" id="non_horiz_white">{@code \H}</th>
167 * <td headers="matches predef non_horiz_white">A non-horizontal whitespace character: {@code [^\h]}</td></tr>
168 * <tr><th style="vertical-align:top; font-weight:normal" id="white">{@code \s}</th>
169 * <td headers="matches predef white">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
170 * <tr><th style="vertical-align:top; font-weight:normal" id="non_white">{@code \S}</th>
171 * <td headers="matches predef non_white">A non-whitespace character: {@code [^\s]}</td></tr>
172 * <tr><th style="vertical-align:top; font-weight:normal" id="vert_white">{@code \v}</th>
173 * <td headers="matches predef vert_white">A vertical whitespace character: <code>[\n\x0B\f\r\x85\u2028\u2029]</code>
174 * </td></tr>
175 * <tr><th style="vertical-align:top; font-weight:normal" id="non_vert_white">{@code \V}</th>
176 * <td headers="matches predef non_vert_white">A non-vertical whitespace character: {@code [^\v]}</td></tr>
177 * <tr><th style="vertical-align:top; font-weight:normal" id="word">{@code \w}</th>
178 * <td headers="matches predef word">A word character: {@code [a-zA-Z_0-9]}</td></tr>
179 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word">{@code \W}</th>
180 * <td headers="matches predef non_word">A non-word character: {@code [^\w]}</td></tr>
181 *
182 * <tr><th colspan="2" style="padding-top:20px" id="posix"><b>POSIX character classes (US-ASCII only)</b></th></tr>
183 *
184 * <tr><th style="vertical-align:top; font-weight:normal" id="Lower">{@code \p{Lower}}</th>
185 * <td headers="matches posix Lower">A lower-case alphabetic character: {@code [a-z]}</td></tr>
186 * <tr><th style="vertical-align:top; font-weight:normal" id="Upper">{@code \p{Upper}}</th>
187 * <td headers="matches posix Upper">An upper-case alphabetic character:{@code [A-Z]}</td></tr>
188 * <tr><th style="vertical-align:top; font-weight:normal" id="ASCII">{@code \p{ASCII}}</th>
189 * <td headers="matches posix ASCII">All ASCII:{@code [\x00-\x7F]}</td></tr>
190 * <tr><th style="vertical-align:top; font-weight:normal" id="Alpha">{@code \p{Alpha}}</th>
191 * <td headers="matches posix Alpha">An alphabetic character:{@code [\p{Lower}\p{Upper}]}</td></tr>
192 * <tr><th style="vertical-align:top; font-weight:normal" id="Digit">{@code \p{Digit}}</th>
193 * <td headers="matches posix Digit">A decimal digit: {@code [0-9]}</td></tr>
194 * <tr><th style="vertical-align:top; font-weight:normal" id="Alnum">{@code \p{Alnum}}</th>
195 * <td headers="matches posix Alnum">An alphanumeric character:{@code [\p{Alpha}\p{Digit}]}</td></tr>
196 * <tr><th style="vertical-align:top; font-weight:normal" id="Punct">{@code \p{Punct}}</th>
197 * <td headers="matches posix Punct">Punctuation: One of {@code !"#$%&‘()*+,-./:;<=>[email protected][\]^_`{|}~}</td></tr>
198 * <!-- {@code [\!"#\$%&‘\(\)\*\+,\-\./:;\<=\>\[email protected]\[\\\]\^_`\{\|\}~]}
199 * {@code [\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]} -->
200 * <tr><th style="vertical-align:top; font-weight:normal" id="Graph">{@code \p{Graph}}</th>
201 * <td headers="matches posix Graph">A visible character: {@code [\p{Alnum}\p{Punct}]}</td></tr>
202 * <tr><th style="vertical-align:top; font-weight:normal" id="Print">{@code \p{Print}}</th>
203 * <td headers="matches posix Print">A printable character: {@code [\p{Graph}\x20]}</td></tr>
204 * <tr><th style="vertical-align:top; font-weight:normal" id="Blank">{@code \p{Blank}}</th>
205 * <td headers="matches posix Blank">A space or a tab: {@code [ \t]}</td></tr>
206 * <tr><th style="vertical-align:top; font-weight:normal" id="Cntrl">{@code \p{Cntrl}}</th>
207 * <td headers="matches posix Cntrl">A control character: {@code [\x00-\x1F\x7F]}</td></tr>
208 * <tr><th style="vertical-align:top; font-weight:normal" id="XDigit">{@code \p{XDigit}}</th>
209 * <td headers="matches posix XDigit">A hexadecimal digit: {@code [0-9a-fA-F]}</td></tr>
210 * <tr><th style="vertical-align:top; font-weight:normal" id="Space">{@code \p{Space}}</th>
211 * <td headers="matches posix Space">A whitespace character: {@code [ \t\n\x0B\f\r]}</td></tr>
212 *
213 * <tr><th colspan="2" style="padding-top:20px" id="java">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr>
214 *
215 * <tr><th style="vertical-align:top; font-weight:normal" id="javaLowerCase">{@code \p{javaLowerCase}}</th>
216 * <td headers="matches java javaLowerCase">Equivalent to java.lang.Character.isLowerCase()</td></tr>
217 * <tr><th style="vertical-align:top; font-weight:normal" id="javaUpperCase">{@code \p{javaUpperCase}}</th>
218 * <td headers="matches java javaUpperCase">Equivalent to java.lang.Character.isUpperCase()</td></tr>
219 * <tr><th style="vertical-align:top; font-weight:normal" id="javaWhitespace">{@code \p{javaWhitespace}}</th>
220 * <td headers="matches java javaWhitespace">Equivalent to java.lang.Character.isWhitespace()</td></tr>
221 * <tr><th style="vertical-align:top; font-weight:normal" id="javaMirrored">{@code \p{javaMirrored}}</th>
222 * <td headers="matches java javaMirrored">Equivalent to java.lang.Character.isMirrored()</td></tr>
223 *
224 * <tr><th colspan="2" style="padding-top:20px" id="unicode">Classes for Unicode scripts, blocks, categories and binary properties</th></tr>
225 *
226 * <tr><th style="vertical-align:top; font-weight:normal" id="IsLatin">{@code \p{IsLatin}}</th>
227 * <td headers="matches unicode IsLatin">A Latin script character (<a href="#usc">script</a>)</td></tr>
228 * <tr><th style="vertical-align:top; font-weight:normal" id="InGreek">{@code \p{InGreek}}</th>
229 * <td headers="matches unicode InGreek">A character in the Greek block (<a href="#ubc">block</a>)</td></tr>
230 * <tr><th style="vertical-align:top; font-weight:normal" id="Lu">{@code \p{Lu}}</th>
231 * <td headers="matches unicode Lu">An uppercase letter (<a href="#ucc">category</a>)</td></tr>
232 * <tr><th style="vertical-align:top; font-weight:normal" id="IsAlphabetic">{@code \p{IsAlphabetic}}</th>
233 * <td headers="matches unicode IsAlphabetic">An alphabetic character (<a href="#ubpc">binary property</a>)</td></tr>
234 * <tr><th style="vertical-align:top; font-weight:normal" id="Sc">{@code \p{Sc}}</th>
235 * <td headers="matches unicode Sc">A currency symbol</td></tr>
236 * <tr><th style="vertical-align:top; font-weight:normal" id="not_InGreek">{@code \P{InGreek}}</th>
237 * <td headers="matches unicode not_InGreek">Any character except one in the Greek block (negation)</td></tr>
238 * <tr><th style="vertical-align:top; font-weight:normal" id="not_uppercase">{@code [\p{L}&&[^\p{Lu}]]}</th>
239 * <td headers="matches unicode not_uppercase">Any letter except an uppercase letter (subtraction)</td></tr>
240 *
241 * <tr><th colspan="2" style="padding-top:20px" id="bounds">Boundary matchers</th></tr>
242 *
243 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_line">{@code ^}</th>
244 * <td headers="matches bounds begin_line">The beginning of a line</td></tr>
245 * <tr><th style="vertical-align:top; font-weight:normal" id="end_line">{@code $}</th>
246 * <td headers="matches bounds end_line">The end of a line</td></tr>
247 * <tr><th style="vertical-align:top; font-weight:normal" id="word_boundary">{@code \b}</th>
248 * <td headers="matches bounds word_boundary">A word boundary</td></tr>
249 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_cluster_boundary">{@code \b{g}}</th>
250 * <td headers="matches bounds grapheme_cluster_boundary">A Unicode extended grapheme cluster boundary</td></tr>
251 * <tr><th style="vertical-align:top; font-weight:normal" id="non_word_boundary">{@code \B}</th>
252 * <td headers="matches bounds non_word_boundary">A non-word boundary</td></tr>
253 * <tr><th style="vertical-align:top; font-weight:normal" id="begin_input">{@code \A}</th>
254 * <td headers="matches bounds begin_input">The beginning of the input</td></tr>
255 * <tr><th style="vertical-align:top; font-weight:normal" id="end_prev_match">{@code \G}</th>
256 * <td headers="matches bounds end_prev_match">The end of the previous match</td></tr>
257 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input_except_term">{@code \Z}</th>
258 * <td headers="matches bounds end_input_except_term">The end of the input but for the final
259 * <a href="#lt">terminator</a>, if any</td></tr>
260 * <tr><th style="vertical-align:top; font-weight:normal" id="end_input">{@code \z}</th>
261 * <td headers="matches bounds end_input">The end of the input</td></tr>
262 *
263 * <tr><th colspan="2" style="padding-top:20px" id="linebreak">Linebreak matcher</th></tr>
264 *
265 * <tr><th style="vertical-align:top; font-weight:normal" id="any_unicode_linebreak">{@code \R}</th>
266 * <td headers="matches linebreak any_unicode_linebreak">Any Unicode linebreak sequence, is equivalent to
267 * <code>\u000D\u000A|[\u000A\u000B\u000C\u000D\u0085\u2028\u2029]
268 * </code></td></tr>
269 *
270 * <tr><th colspan="2" style="padding-top:20px" id="grapheme">Unicode Extended Grapheme matcher</th></tr>
271 *
272 * <tr><th style="vertical-align:top; font-weight:normal" id="grapheme_any">{@code \X}</th>
273 * <td headers="matches grapheme grapheme_any">Any Unicode extended grapheme cluster</td></tr>
274 *
275 * <tr><th colspan="2" style="padding-top:20px" id="greedy">Greedy quantifiers</th></tr>
276 *
277 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_once_or_not"><i>X</i>{@code ?}</th>
278 * <td headers="matches greedy greedy_once_or_not"><i>X</i>, once or not at all</td></tr>
279 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_zero_or_more"><i>X</i>{@code *}</th>
280 * <td headers="matches greedy greedy_zero_or_more"><i>X</i>, zero or more times</td></tr>
281 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_one_or_more"><i>X</i>{@code +}</th>
282 * <td headers="matches greedy greedy_one_or_more"><i>X</i>, one or more times</td></tr>
283 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_exactly"><i>X</i><code>{</code><i>n</i><code>}</code></th>
284 * <td headers="matches greedy greedy_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
285 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least"><i>X</i><code>{</code><i>n</i>{@code ,}}</th>
286 * <td headers="matches greedy greedy_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
287 * <tr><th style="vertical-align:top; font-weight:normal" id="greedy_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}</code></th>
288 * <td headers="matches greedy greedy_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
289 *
290 * <tr><th colspan="2" style="padding-top:20px" id="reluc">Reluctant quantifiers</th></tr>
291 *
292 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_once_or_not"><i>X</i>{@code ??}</th>
293 * <td headers="matches reluc reluc_once_or_not"><i>X</i>, once or not at all</td></tr>
294 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_zero_or_more"><i>X</i>{@code *?}</th>
295 * <td headers="matches reluc reluc_zero_or_more"><i>X</i>, zero or more times</td></tr>
296 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_one_or_more"><i>X</i>{@code +?}</th>
297 * <td headers="matches reluc reluc_one_or_more"><i>X</i>, one or more times</td></tr>
298 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_exactly"><i>X</i><code>{</code><i>n</i><code>}?</code></th>
299 * <td headers="matches reluc reluc_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
300 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least"><i>X</i><code>{</code><i>n</i><code>,}?</code></th>
301 * <td headers="matches reluc reluc_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
302 * <tr><th style="vertical-align:top; font-weight:normal" id="reluc_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}?</code></th>
303 * <td headers="matches reluc reluc_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
304 *
305 * <tr><th colspan="2" style="padding-top:20px" id="poss">Possessive quantifiers</th></tr>
306 *
307 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_once_or_not"><i>X</i>{@code ?+}</th>
308 * <td headers="matches poss poss_once_or_not"><i>X</i>, once or not at all</td></tr>
309 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_zero_or_more"><i>X</i>{@code *+}</th>
310 * <td headers="matches poss poss_zero_or_more"><i>X</i>, zero or more times</td></tr>
311 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_one_or_more"><i>X</i>{@code ++}</th>
312 * <td headers="matches poss poss_one_or_more"><i>X</i>, one or more times</td></tr>
313 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_exactly"><i>X</i><code>{</code><i>n</i><code>}+</code></th>
314 * <td headers="matches poss poss_exactly"><i>X</i>, exactly <i>n</i> times</td></tr>
315 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least"><i>X</i><code>{</code><i>n</i><code>,}+</code></th>
316 * <td headers="matches poss poss_at_least"><i>X</i>, at least <i>n</i> times</td></tr>
317 * <tr><th style="vertical-align:top; font-weight:normal" id="poss_at_least_up_to"><i>X</i><code>{</code><i>n</i>{@code ,}<i>m</i><code>}+</code></th>
318 * <td headers="matches poss poss_at_least_up_to"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
319 *
320 * <tr><th colspan="2" style="padding-top:20px" id="logical">Logical operators</th></tr>
321 *
322 * <tr><th style="vertical-align:top; font-weight:normal" id="concat"><i>XY</i></th>
323 * <td headers="matches logical concat"><i>X</i> followed by <i>Y</i></td></tr>
324 * <tr><th style="vertical-align:top; font-weight:normal" id="alternate"><i>X</i>{@code |}<i>Y</i></th>
325 * <td headers="matches logical alternate">Either <i>X</i> or <i>Y</i></td></tr>
326 * <tr><th style="vertical-align:top; font-weight:normal" id="group">{@code (}<i>X</i>{@code )}</th>
327 * <td headers="matches logical group">X, as a <a href="#cg">capturing group</a></td></tr>
328 *
329 * <tr><th colspan="2" style="padding-top:20px" id="backref">Back references</th></tr>
330 *
331 * <tr><th style="vertical-align:top; font-weight:normal" id="back_nth">{@code \}<i>n</i></th>
332 * <td headers="matches backref back_nth">Whatever the <i>n</i><sup>th</sup>
333 * <a href="#cg">capturing group</a> matched</td></tr>
334 * <tr><th style="vertical-align:top; font-weight:normal" id="back_named">{@code \}<i>k</i><<i>name</i>></th>
335 * <td headers="matches backref back_named">Whatever the
336 * <a href="#groupname">named-capturing group</a> "name" matched</td></tr>
337 *
338 * <tr><th colspan="2" style="padding-top:20px" id="quote">Quotation</th></tr>
339 *
340 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_follow">{@code \}</th>
341 * <td headers="matches quote quote_follow">Nothing, but quotes the following character</td></tr>
342 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_begin">{@code \Q}</th>
343 * <td headers="matches quote quote_begin">Nothing, but quotes all characters until {@code \E}</td></tr>
344 * <tr><th style="vertical-align:top; font-weight:normal" id="quote_end">{@code \E}</th>
345 * <td headers="matches quote quote_end">Nothing, but ends quoting started by {@code \Q}</td></tr>
346 * <!-- Metachars: !$()*+.<>?[\]^{|} -->
347 *
348 * <tr><th colspan="2" style="padding-top:20px" id="special">Special constructs (named-capturing and non-capturing)</th></tr>
349 *
350 * <tr><th style="vertical-align:top; font-weight:normal" id="named_group"><code>(?<<a href="#groupname">name</a>></code><i>X</i>{@code )}</th>
351 * <td headers="matches special named_group"><i>X</i>, as a named-capturing group</td></tr>
352 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group">{@code (?:}<i>X</i>{@code )}</th>
353 * <td headers="matches special non_capture_group"><i>X</i>, as a non-capturing group</td></tr>
354 * <tr><th style="vertical-align:top; font-weight:normal" id="flags"><code>(?idmsuxU-idmsuxU) </code></th>
355 * <td headers="matches special flags">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a>
356 * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a>
357 * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> <a href="#UNICODE_CHARACTER_CLASS">U</a>
358 * on - off</td></tr>
359 * <tr><th style="vertical-align:top; font-weight:normal" id="non_capture_group_flags"><code>(?idmsux-idmsux:</code><i>X</i>{@code )} </th>
360 * <td headers="matches special non_capture_group_flags"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the
361 * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a>
362 * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a >
363 * <a href="#COMMENTS">x</a> on - off</td></tr>
364 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookahead">{@code (?=}<i>X</i>{@code )}</th>
365 * <td headers="matches special pos_lookahead"><i>X</i>, via zero-width positive lookahead</td></tr>
366 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookahead">{@code (?!}<i>X</i>{@code )}</th>
367 * <td headers="matches special neg_lookahead"><i>X</i>, via zero-width negative lookahead</td></tr>
368 * <tr><th style="vertical-align:top; font-weight:normal" id="pos_lookbehind">{@code (?<=}<i>X</i>{@code )}</th>
369 * <td headers="matches special pos_lookbehind"><i>X</i>, via zero-width positive lookbehind</td></tr>
370 * <tr><th style="vertical-align:top; font-weight:normal" id="neg_lookbehind">{@code (?<!}<i>X</i>{@code )}</th>
371 * <td headers="matches special neg_lookbehind"><i>X</i>, via zero-width negative lookbehind</td></tr>
372 * <tr><th style="vertical-align:top; font-weight:normal" id="indep_non_capture_group">{@code (?>}<i>X</i>{@code )}</th>
373 * <td headers="matches special indep_non_capture_group"><i>X</i>, as an independent, non-capturing group</td></tr>
374 *
375 * </tbody>
376 * </table>
377 *
378 * <hr>
379 *
380 *
381 * <h3><a id="bs">Backslashes, escapes, and quoting</a></h3>
382 *
383 * <p> The backslash character ({@code ‘\‘}) serves to introduce escaped
384 * constructs, as defined in the table above, as well as to quote characters
385 * that otherwise would be interpreted as unescaped constructs. Thus the
386 * expression {@code \\} matches a single backslash and <code>\{</code> matches a
387 * left brace.
388 *
389 * <p> It is an error to use a backslash prior to any alphabetic character that
390 * does not denote an escaped construct; these are reserved for future
391 * extensions to the regular-expression language. A backslash may be used
392 * prior to a non-alphabetic character regardless of whether that character is
393 * part of an unescaped construct.
394 *
395 * <p> Backslashes within string literals in Java source code are interpreted
396 * as required by
397 * <cite>The Java™ Language Specification</cite>
398 * as either Unicode escapes (section 3.3) or other character escapes (section 3.10.6)
399 * It is therefore necessary to double backslashes in string
400 * literals that represent regular expressions to protect them from
401 * interpretation by the Java bytecode compiler. The string literal
402 * <code>"\b"</code>, for example, matches a single backspace character when
403 * interpreted as a regular expression, while {@code "\\b"} matches a
404 * word boundary. The string literal {@code "\(hello\)"} is illegal
405 * and leads to a compile-time error; in order to match the string
406 * {@code (hello)} the string literal {@code "\\(hello\\)"}
407 * must be used.
408 *
409 * <h3><a id="cc">Character Classes</a></h3>
410 *
411 * <p> Character classes may appear within other character classes, and
412 * may be composed by the union operator (implicit) and the intersection
413 * operator ({@code &&}).
414 * The union operator denotes a class that contains every character that is
415 * in at least one of its operand classes. The intersection operator
416 * denotes a class that contains every character that is in both of its
417 * operand classes.
418 *
419 * <p> The precedence of character-class operators is as follows, from
420 * highest to lowest:
421 *
422 * <table class="striped" style="margin-left: 2em;">
423 * <caption style="display:none">Precedence of character class operators.</caption>
424 * <thead>
425 * <tr><th scope="col">Precedence<th scope="col">Name<th scope="col">Example
426 * </thead>
427 * <tbody>
428 * <tr><th scope="row">1</th>
429 * <td>Literal escape </td>
430 * <td>{@code \x}</td></tr>
431 * <tr><th scope="row">2</th>
432 * <td>Grouping</td>
433 * <td>{@code [...]}</td></tr>
434 * <tr><th scope="row">3</th>
435 * <td>Range</td>
436 * <td>{@code a-z}</td></tr>
437 * <tr><th scope="row">4</th>
438 * <td>Union</td>
439 * <td>{@code [a-e][i-u]}</td></tr>
440 * <tr><th scope="row">5</th>
441 * <td>Intersection</td>
442 * <td>{@code [a-z&&[aeiou]]}</td></tr>
443 * </tbody>
444 * </table>
445 *
446 * <p> Note that a different set of metacharacters are in effect inside
447 * a character class than outside a character class. For instance, the
448 * regular expression {@code .} loses its special meaning inside a
449 * character class, while the expression {@code -} becomes a range
450 * forming metacharacter.
451 *
452 * <h3><a id="lt">Line terminators</a></h3>
453 *
454 * <p> A <i>line terminator</i> is a one- or two-character sequence that marks
455 * the end of a line of the input character sequence. The following are
456 * recognized as line terminators:
457 *
458 * <ul>
459 *
460 * <li> A newline (line feed) character ({@code ‘\n‘}),
461 *
462 * <li> A carriage-return character followed immediately by a newline
463 * character ({@code "\r\n"}),
464 *
465 * <li> A standalone carriage-return character ({@code ‘\r‘}),
466 *
467 * <li> A next-line character (<code>‘\u0085‘</code>),
468 *
469 * <li> A line-separator character (<code>‘\u2028‘</code>), or
470 *
471 * <li> A paragraph-separator character (<code>‘\u2029‘</code>).
472 *
473 * </ul>
474 * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators
475 * recognized are newline characters.
476 *
477 * <p> The regular expression {@code .} matches any character except a line
478 * terminator unless the {@link #DOTALL} flag is specified.
479 *
480 * <p> By default, the regular expressions {@code ^} and {@code $} ignore
481 * line terminators and only match at the beginning and the end, respectively,
482 * of the entire input sequence. If {@link #MULTILINE} mode is activated then
483 * {@code ^} matches at the beginning of input and after any line terminator
484 * except at the end of input. When in {@link #MULTILINE} mode {@code $}
485 * matches just before a line terminator or the end of the input sequence.
486 *
487 * <h3><a id="cg">Groups and capturing</a></h3>
488 *
489 * <h4><a id="gnumber">Group number</a></h4>
490 * <p> Capturing groups are numbered by counting their opening parentheses from
491 * left to right. In the expression {@code ((A)(B(C)))}, for example, there
492 * are four such groups: </p>
493 *
494 * <ol style="margin-left:2em;">
495 * <li> {@code ((A)(B(C)))}
496 * <li> {@code (A)}
497 * <li> {@code (B(C))}
498 * <li> {@code (C)}
499 * </ol>
500 *
501 * <p> Group zero always stands for the entire expression.
502 *
503 * <p> Capturing groups are so named because, during a match, each subsequence
504 * of the input sequence that matches such a group is saved. The captured
505 * subsequence may be used later in the expression, via a back reference, and
506 * may also be retrieved from the matcher once the match operation is complete.
507 *
508 * <h4><a id="groupname">Group name</a></h4>
509 * <p>A capturing group can also be assigned a "name", a {@code named-capturing group},
510 * and then be back-referenced later by the "name". Group names are composed of
511 * the following characters. The first character must be a {@code letter}.
512 *
513 * <ul>
514 * <li> The uppercase letters {@code ‘A‘} through {@code ‘Z‘}
515 * (<code>‘\u0041‘</code> through <code>‘\u005a‘</code>),
516 * <li> The lowercase letters {@code ‘a‘} through {@code ‘z‘}
517 * (<code>‘\u0061‘</code> through <code>‘\u007a‘</code>),
518 * <li> The digits {@code ‘0‘} through {@code ‘9‘}
519 * (<code>‘\u0030‘</code> through <code>‘\u0039‘</code>),
520 * </ul>
521 *
522 * <p> A {@code named-capturing group} is still numbered as described in
523 * <a href="#gnumber">Group number</a>.
524 *
525 * <p> The captured input associated with a group is always the subsequence
526 * that the group most recently matched. If a group is evaluated a second time
527 * because of quantification then its previously-captured value, if any, will
528 * be retained if the second evaluation fails. Matching the string
529 * {@code "aba"} against the expression {@code (a(b)?)+}, for example, leaves
530 * group two set to {@code "b"}. All captured input is discarded at the
531 * beginning of each match.
532 *
533 * <p> Groups beginning with {@code (?} are either pure, <i>non-capturing</i> groups
534 * that do not capture text and do not count towards the group total, or
535 * <i>named-capturing</i> group.
536 *
537 * <h3> Unicode support </h3>
538 *
539 * <p> This class is in conformance with Level 1 of <a
540 * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
541 * Standard #18: Unicode Regular Expression</i></a>, plus RL2.1
542 * Canonical Equivalents.
543 * <p>
544 * <b>Unicode escape sequences</b> such as <code>\u2014</code> in Java source code
545 * are processed as described in section 3.3 of
546 * <cite>The Java™ Language Specification</cite>.
547 * Such escape sequences are also implemented directly by the regular-expression
548 * parser so that Unicode escapes can be used in expressions that are read from
549 * files or from the keyboard. Thus the strings <code>"\u2014"</code> and
550 * {@code "\\u2014"}, while not equal, compile into the same pattern, which
551 * matches the character with hexadecimal value {@code 0x2014}.
552 * <p>
553 * A Unicode character can also be represented by using its <b>Hex notation</b>
554 * (hexadecimal code point value) directly as described in construct
555 * <code>\x{...}</code>, for example a supplementary character U+2011F can be
556 * specified as <code>\x{2011F}</code>, instead of two consecutive Unicode escape
557 * sequences of the surrogate pair <code>\uD840</code><code>\uDD1F</code>.
558 * <p>
559 * <b>Unicode character names</b> are supported by the named character construct
560 * <code>\N{</code>...<code>}</code>, for example, <code>\N{WHITE SMILING FACE}</code>
561 * specifies character <code>\u263A</code>. The character names supported
562 * by this class are the valid Unicode character names matched by
563 * {@link java.lang.Character#codePointOf(String) Character.codePointOf(name)}.
564 * <p>
565 * <a href="http://www.unicode.org/reports/tr18/#Default_Grapheme_Clusters">
566 * <b>Unicode extended grapheme clusters</b></a> are supported by the grapheme
567 * cluster matcher {@code \X} and the corresponding boundary matcher {@code \b{g}}.
568 * <p>
569 * Unicode scripts, blocks, categories and binary properties are written with
570 * the {@code \p} and {@code \P} constructs as in Perl.
571 * <code>\p{</code><i>prop</i><code>}</code> matches if
572 * the input has the property <i>prop</i>, while <code>\P{</code><i>prop</i><code>}</code>
573 * does not match if the input has that property.
574 * <p>
575 * Scripts, blocks, categories and binary properties can be used both inside
576 * and outside of a character class.
577 *
578 * <p>
579 * <b><a id="usc">Scripts</a></b> are specified either with the prefix {@code Is}, as in
580 * {@code IsHiragana}, or by using the {@code script} keyword (or its short
581 * form {@code sc}) as in {@code script=Hiragana} or {@code sc=Hiragana}.
582 * <p>
583 * The script names supported by {@code Pattern} are the valid script names
584 * accepted and defined by
585 * {@link java.lang.Character.UnicodeScript#forName(String) UnicodeScript.forName}.
586 *
587 * <p>
588 * <b><a id="ubc">Blocks</a></b> are specified with the prefix {@code In}, as in
589 * {@code InMongolian}, or by using the keyword {@code block} (or its short
590 * form {@code blk}) as in {@code block=Mongolian} or {@code blk=Mongolian}.
591 * <p>
592 * The block names supported by {@code Pattern} are the valid block names
593 * accepted and defined by
594 * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}.
595 * <p>
596 *
597 * <b><a id="ucc">Categories</a></b> may be specified with the optional prefix {@code Is}:
598 * Both {@code \p{L}} and {@code \p{IsL}} denote the category of Unicode
599 * letters. Same as scripts and blocks, categories can also be specified
600 * by using the keyword {@code general_category} (or its short form
601 * {@code gc}) as in {@code general_category=Lu} or {@code gc=Lu}.
602 * <p>
603 * The supported categories are those of
604 * <a href="http://www.unicode.org/unicode/standard/standard.html">
605 * <i>The Unicode Standard</i></a> in the version specified by the
606 * {@link java.lang.Character Character} class. The category names are those
607 * defined in the Standard, both normative and informative.
608 * <p>
609 *
610 * <b><a id="ubpc">Binary properties</a></b> are specified with the prefix {@code Is}, as in
611 * {@code IsAlphabetic}. The supported binary properties by {@code Pattern}
612 * are
613 * <ul>
614 * <li> Alphabetic
615 * <li> Ideographic
616 * <li> Letter
617 * <li> Lowercase
618 * <li> Uppercase
619 * <li> Titlecase
620 * <li> Punctuation
621 * <Li> Control
622 * <li> White_Space
623 * <li> Digit
624 * <li> Hex_Digit
625 * <li> Join_Control
626 * <li> Noncharacter_Code_Point
627 * <li> Assigned
628 * </ul>
629 * <p>
630 * The following <b>Predefined Character classes</b> and <b>POSIX character classes</b>
631 * are in conformance with the recommendation of <i>Annex C: Compatibility Properties</i>
632 * of <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Regular Expression
633 * </i></a>, when {@link #UNICODE_CHARACTER_CLASS} flag is specified.
634 *
635 * <table class="striped">
636 * <caption style="display:none">predefined and posix character classes in Unicode mode</caption>
637 * <thead>
638 * <tr>
639 * <th scope="col" id="predef_classes">Classes</th>
640 * <th scope="col" id="predef_matches">Matches</th>
641 * </tr>
642 * </thead>
643 * <tbody>
644 * <tr><th scope="row">{@code \p{Lower}}</th>
645 * <td>A lowercase character:{@code \p{IsLowercase}}</td></tr>
646 * <tr><th scope="row">{@code \p{Upper}}</th>
647 * <td>An uppercase character:{@code \p{IsUppercase}}</td></tr>
648 * <tr><th scope="row">{@code \p{ASCII}}</th>
649 * <td>All ASCII:{@code [\x00-\x7F]}</td></tr>
650 * <tr><th scope="row">{@code \p{Alpha}}</th>
651 * <td>An alphabetic character:{@code \p{IsAlphabetic}}</td></tr>
652 * <tr><th scope="row">{@code \p{Digit}}</th>
653 * <td>A decimal digit character:{@code \p{IsDigit}}</td></tr>
654 * <tr><th scope="row">{@code \p{Alnum}}</th>
655 * <td>An alphanumeric character:{@code [\p{IsAlphabetic}\p{IsDigit}]}</td></tr>
656 * <tr><th scope="row">{@code \p{Punct}}</th>
657 * <td>A punctuation character:{@code \p{IsPunctuation}}</td></tr>
658 * <tr><th scope="row">{@code \p{Graph}}</th>
659 * <td>A visible character: {@code [^\p{IsWhite_Space}\p{gc=Cc}\p{gc=Cs}\p{gc=Cn}]}</td></tr>
660 * <tr><th scope="row">{@code \p{Print}}</th>
661 * <td>A printable character: {@code [\p{Graph}\p{Blank}&&[^\p{Cntrl}]]}</td></tr>
662 * <tr><th scope="row">{@code \p{Blank}}</th>
663 * <td>A space or a tab: {@code [\p{IsWhite_Space}&&[^\p{gc=Zl}\p{gc=Zp}\x0a\x0b\x0c\x0d\x85]]}</td></tr>
664 * <tr><th scope="row">{@code \p{Cntrl}}</th>
665 * <td>A control character: {@code \p{gc=Cc}}</td></tr>
666 * <tr><th scope="row">{@code \p{XDigit}}</th>
667 * <td>A hexadecimal digit: {@code [\p{gc=Nd}\p{IsHex_Digit}]}</td></tr>
668 * <tr><th scope="row">{@code \p{Space}}</th>
669 * <td>A whitespace character:{@code \p{IsWhite_Space}}</td></tr>
670 * <tr><th scope="row">{@code \d}</th>
671 * <td>A digit: {@code \p{IsDigit}}</td></tr>
672 * <tr><th scope="row">{@code \D}</th>
673 * <td>A non-digit: {@code [^\d]}</td></tr>
674 * <tr><th scope="row">{@code \s}</th>
675 * <td>A whitespace character: {@code \p{IsWhite_Space}}</td></tr>
676 * <tr><th scope="row">{@code \S}</th>
677 * <td>A non-whitespace character: {@code [^\s]}</td></tr>
678 * <tr><th scope="row">{@code \w}</th>
679 * <td>A word character: {@code [\p{Alpha}\p{gc=Mn}\p{gc=Me}\p{gc=Mc}\p{Digit}\p{gc=Pc}\p{IsJoin_Control}]}</td></tr>
680 * <tr><th scope="row">{@code \W}</th>
681 * <td>A non-word character: {@code [^\w]}</td></tr>
682 * </tbody>
683 * </table>
684 * <p>
685 * <a id="jcc">
686 * Categories that behave like the java.lang.Character
687 * boolean is<i>methodname</i> methods (except for the deprecated ones) are
688 * available through the same <code>\p{</code><i>prop</i><code>}</code> syntax where
689 * the specified property has the name <code>java<i>methodname</i></code></a>.
690 *
691 * <h3> Comparison to Perl 5 </h3>
692 *
693 * <p>The {@code Pattern} engine performs traditional NFA-based matching
694 * with ordered alternation as occurs in Perl 5.
695 *
696 * <p> Perl constructs not supported by this class: </p>
697 *
698 * <ul>
699 * <li><p> The backreference constructs, <code>\g{</code><i>n</i><code>}</code> for
700 * the <i>n</i><sup>th</sup><a href="#cg">capturing group</a> and
701 * <code>\g{</code><i>name</i><code>}</code> for
702 * <a href="#groupname">named-capturing group</a>.
703 * </p></li>
704 *
705 * <li><p> The conditional constructs
706 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code )} and
707 * {@code (?(}<i>condition</i>{@code )}<i>X</i>{@code |}<i>Y</i>{@code )},
708 * </p></li>
709 *
710 * <li><p> The embedded code constructs <code>(?{</code><i>code</i><code>})</code>
711 * and <code>(??{</code><i>code</i><code>})</code>,</p></li>
712 *
713 * <li><p> The embedded comment syntax {@code (?#comment)}, and </p></li>
714 *
715 * <li><p> The preprocessing operations {@code \l} <code>\u</code>,
716 * {@code \L}, and {@code \U}. </p></li>
717 *
718 * </ul>
719 *
720 * <p> Constructs supported by this class but not by Perl: </p>
721 *
722 * <ul>
723 *
724 * <li><p> Character-class union and intersection as described
725 * <a href="#cc">above</a>.</p></li>
726 *
727 * </ul>
728 *
729 * <p> Notable differences from Perl: </p>
730 *
731 * <ul>
732 *
733 * <li><p> In Perl, {@code \1} through {@code \9} are always interpreted
734 * as back references; a backslash-escaped number greater than {@code 9} is
735 * treated as a back reference if at least that many subexpressions exist,
736 * otherwise it is interpreted, if possible, as an octal escape. In this
737 * class octal escapes must always begin with a zero. In this class,
738 * {@code \1} through {@code \9} are always interpreted as back
739 * references, and a larger number is accepted as a back reference if at
740 * least that many subexpressions exist at that point in the regular
741 * expression, otherwise the parser will drop digits until the number is
742 * smaller or equal to the existing number of groups or it is one digit.
743 * </p></li>
744 *
745 * <li><p> Perl uses the {@code g} flag to request a match that resumes
746 * where the last match left off. This functionality is provided implicitly
747 * by the {@link Matcher} class: Repeated invocations of the {@link
748 * Matcher#find find} method will resume where the last match left off,
749 * unless the matcher is reset. </p></li>
750 *
751 * <li><p> In Perl, embedded flags at the top level of an expression affect
752 * the whole expression. In this class, embedded flags always take effect
753 * at the point at which they appear, whether they are at the top level or
754 * within a group; in the latter case, flags are restored at the end of the
755 * group just as in Perl. </p></li>
756 *
757 * </ul>
758 *
759 *
760 * <p> For a more precise description of the behavior of regular expression
761 * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/">
762 * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl,
763 * O‘Reilly and Associates, 2006.</a>
764 * </p>
765 *
766 * @see java.lang.String#split(String, int)
767 * @see java.lang.String#split(String)
768 *
769 * @author Mike McCloskey
770 * @author Mark Reinhold
771 * @author JSR-51 Expert Group
772 * @since 1.4
773 * @spec JSR-51
774 */
775
776 public final class Pattern
777 implements java.io.Serializable
778 {
779
780 /**
781 * Regular expression modifier values. Instead of being passed as
782 * arguments, they can also be passed as inline modifiers.
783 * For example, the following statements have the same effect.
784 * <pre>
785 * Pattern p1 = Pattern.compile("abc", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE);
786 * Pattern p2 = Pattern.compile("(?im)abc", 0);
787 * </pre>
788 */
789
790 /**
791 * Enables Unix lines mode.
792 *
793 * <p> In this mode, only the {@code ‘\n‘} line terminator is recognized
794 * in the behavior of {@code .}, {@code ^}, and {@code $}.
795 *
796 * <p> Unix lines mode can also be enabled via the embedded flag
797 * expression {@code (?d)}.
798 */
799 public static final int UNIX_LINES = 0x01;
800
801 /**
802 * Enables case-insensitive matching.
803 *
804 * <p> By default, case-insensitive matching assumes that only characters
805 * in the US-ASCII charset are being matched. Unicode-aware
806 * case-insensitive matching can be enabled by specifying the {@link
807 * #UNICODE_CASE} flag in conjunction with this flag.
808 *
809 * <p> Case-insensitive matching can also be enabled via the embedded flag
810 * expression {@code (?i)}.
811 *
812 * <p> Specifying this flag may impose a slight performance penalty. </p>
813 */
814 public static final int CASE_INSENSITIVE = 0x02;
815
816 /**
817 * Permits whitespace and comments in pattern.
818 *
819 * <p> In this mode, whitespace is ignored, and embedded comments starting
820 * with {@code #} are ignored until the end of a line.
821 *
822 * <p> Comments mode can also be enabled via the embedded flag
823 * expression {@code (?x)}.
824 */
825 public static final int COMMENTS = 0x04;
826
827 /**
828 * Enables multiline mode.
829 *
830 * <p> In multiline mode the expressions {@code ^} and {@code $} match
831 * just after or just before, respectively, a line terminator or the end of
832 * the input sequence. By default these expressions only match at the
833 * beginning and the end of the entire input sequence.
834 *
835 * <p> Multiline mode can also be enabled via the embedded flag
836 * expression {@code (?m)}. </p>
837 */
838 public static final int MULTILINE = 0x08;
839
840 /**
841 * Enables literal parsing of the pattern.
842 *
843 * <p> When this flag is specified then the input string that specifies
844 * the pattern is treated as a sequence of literal characters.
845 * Metacharacters or escape sequences in the input sequence will be
846 * given no special meaning.
847 *
848 * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on
849 * matching when used in conjunction with this flag. The other flags
850 * become superfluous.
851 *
852 * <p> There is no embedded flag character for enabling literal parsing.
853 * @since 1.5
854 */
855 public static final int LITERAL = 0x10;
856
857 /**
858 * Enables dotall mode.
859 *
860 * <p> In dotall mode, the expression {@code .} matches any character,
861 * including a line terminator. By default this expression does not match
862 * line terminators.
863 *
864 * <p> Dotall mode can also be enabled via the embedded flag
865 * expression {@code (?s)}. (The {@code s} is a mnemonic for
866 * "single-line" mode, which is what this is called in Perl.) </p>
867 */
868 public static final int DOTALL = 0x20;
869
870 /**
871 * Enables Unicode-aware case folding.
872 *
873 * <p> When this flag is specified then case-insensitive matching, when
874 * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner
875 * consistent with the Unicode Standard. By default, case-insensitive
876 * matching assumes that only characters in the US-ASCII charset are being
877 * matched.
878 *
879 * <p> Unicode-aware case folding can also be enabled via the embedded flag
880 * expression {@code (?u)}.
881 *
882 * <p> Specifying this flag may impose a performance penalty. </p>
883 */
884 public static final int UNICODE_CASE = 0x40;
885
886 /**
887 * Enables canonical equivalence.
888 *
889 * <p> When this flag is specified then two characters will be considered
890 * to match if, and only if, their full canonical decompositions match.
891 * The expression <code>"a\u030A"</code>, for example, will match the
892 * string <code>"\u00E5"</code> when this flag is specified. By default,
893 * matching does not take canonical equivalence into account.
894 *
895 * <p> There is no embedded flag character for enabling canonical
896 * equivalence.
897 *
898 * <p> Specifying this flag may impose a performance penalty. </p>
899 */
900 public static final int CANON_EQ = 0x80;
901
902 /**
903 * Enables the Unicode version of <i>Predefined character classes</i> and
904 * <i>POSIX character classes</i>.
905 *
906 * <p> When this flag is specified then the (US-ASCII only)
907 * <i>Predefined character classes</i> and <i>POSIX character classes</i>
908 * are in conformance with
909 * <a href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
910 * Standard #18: Unicode Regular Expression</i></a>
911 * <i>Annex C: Compatibility Properties</i>.
912 * <p>
913 * The UNICODE_CHARACTER_CLASS mode can also be enabled via the embedded
914 * flag expression {@code (?U)}.
915 * <p>
916 * The flag implies UNICODE_CASE, that is, it enables Unicode-aware case
917 * folding.
918 * <p>
919 * Specifying this flag may impose a performance penalty. </p>
920 * @since 1.7
921 */
922 public static final int UNICODE_CHARACTER_CLASS = 0x100;
923
924 /**
925 * Contains all possible flags for compile(regex, flags).
926 */
927 private static final int ALL_FLAGS = CASE_INSENSITIVE | MULTILINE |
928 DOTALL | UNICODE_CASE | CANON_EQ | UNIX_LINES | LITERAL |
929 UNICODE_CHARACTER_CLASS | COMMENTS;
930
931 /* Pattern has only two serialized components: The pattern string
932 * and the flags, which are all that is needed to recompile the pattern
933 * when it is deserialized.
934 */
935
936 /** use serialVersionUID from Merlin b59 for interoperability */
937 private static final long serialVersionUID = 5073258162644648461L;
938
939 /**
940 * The original regular-expression pattern string.
941 *
942 * @serial
943 */
944 private String pattern;
945
946 /**
947 * The original pattern flags.
948 *
949 * @serial
950 */
951 private int flags;
952
953 /**
954 * The temporary pattern flags used during compiling. The flags might be turn
955 * on and off by embedded flag.
956 */
957 private transient int flags0;
958
959 /**
960 * Boolean indicating this Pattern is compiled; this is necessary in order
961 * to lazily compile deserialized Patterns.
962 */
963 private transient volatile boolean compiled;
964
965 /**
966 * The normalized pattern string.
967 */
968 private transient String normalizedPattern;
969
970 /**
971 * The starting point of state machine for the find operation. This allows
972 * a match to start anywhere in the input.
973 */
974 transient Node root;
975
976 /**
977 * The root of object tree for a match operation. The pattern is matched
978 * at the beginning. This may include a find that uses BnM or a First
979 * node.
980 */
981 transient Node matchRoot;
982
983 /**
984 * Temporary storage used by parsing pattern slice.
985 */
986 transient int[] buffer;
987
988 /**
989 * A temporary storage used for predicate for double return.
990 */
991 transient CharPredicate predicate;
992
993 /**
994 * Map the "name" of the "named capturing group" to its group id
995 * node.
996 */
997 transient volatile Map<String, Integer> namedGroups;
998
999 /**
1000 * Temporary storage used while parsing group references.
1001 */
1002 transient GroupHead[] groupNodes;
1003
1004 /**
1005 * Temporary storage used to store the top level closure nodes.
1006 */
1007 transient List<Node> topClosureNodes;
1008
1009 /**
1010 * The number of top greedy closure nodes in this Pattern. Used by
1011 * matchers to allocate storage needed for a IntHashSet to keep the
1012 * beginning pos {@code i} of all failed match.
1013 */
1014 transient int localTCNCount;
1015
1016 /*
1017 * Turn off the stop-exponential-backtracking optimization if there
1018 * is a group ref in the pattern.
1019 */
1020 transient boolean hasGroupRef;
1021
1022 /**
1023 * Temporary null terminated code point array used by pattern compiling.
1024 */
1025 private transient int[] temp;
1026
1027 /**
1028 * The number of capturing groups in this Pattern. Used by matchers to
1029 * allocate storage needed to perform a match.
1030 */
1031 transient int capturingGroupCount;
1032
1033 /**
1034 * The local variable count used by parsing tree. Used by matchers to
1035 * allocate storage needed to perform a match.
1036 */
1037 transient int localCount;
1038
1039 /**
1040 * Index into the pattern string that keeps track of how much has been
1041 * parsed.
1042 */
1043 private transient int cursor;
1044
1045 /**
1046 * Holds the length of the pattern string.
1047 */
1048 private transient int patternLength;
1049
1050 /**
1051 * If the Start node might possibly match supplementary characters.
1052 * It is set to true during compiling if
1053 * (1) There is supplementary char in pattern, or
1054 * (2) There is complement node of a "family" CharProperty
1055 */
1056 private transient boolean hasSupplementary;
1057
1058 /**
1059 * Compiles the given regular expression into a pattern.
1060 *
1061 * @param regex
1062 * The expression to be compiled
1063 * @return the given regular expression compiled into a pattern
1064 * @throws PatternSyntaxException
1065 * If the expression‘s syntax is invalid
1066 */
1067 public static Pattern compile(String regex) {
1068 return new Pattern(regex, 0);
1069 }
1070
1071 /**
1072 * Compiles the given regular expression into a pattern with the given
1073 * flags.
1074 *
1075 * @param regex
1076 * The expression to be compiled
1077 *
1078 * @param flags
1079 * Match flags, a bit mask that may include
1080 * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
1081 * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
1082 * {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS}
1083 * and {@link #COMMENTS}
1084 *
1085 * @return the given regular expression compiled into a pattern with the given flags
1086 * @throws IllegalArgumentException
1087 * If bit values other than those corresponding to the defined
1088 * match flags are set in {@code flags}
1089 *
1090 * @throws PatternSyntaxException
1091 * If the expression‘s syntax is invalid
1092 */
1093 public static Pattern compile(String regex, int flags) {
1094 return new Pattern(regex, flags);
1095 }
1096
1097 /**
1098 * Returns the regular expression from which this pattern was compiled.
1099 *
1100 * @return The source of this pattern
1101 */
1102 public String pattern() {
1103 return pattern;
1104 }
1105
1106 /**
1107 * <p>Returns the string representation of this pattern. This
1108 * is the regular expression from which this pattern was
1109 * compiled.</p>
1110 *
1111 * @return The string representation of this pattern
1112 * @since 1.5
1113 */
1114 public String toString() {
1115 return pattern;
1116 }
1117
1118 /**
1119 * Creates a matcher that will match the given input against this pattern.
1120 *
1121 * @param input
1122 * The character sequence to be matched
1123 *
1124 * @return A new matcher for this pattern
1125 */
1126 public Matcher matcher(CharSequence input) {
1127 if (!compiled) {
1128 synchronized(this) {
1129 if (!compiled)
1130 compile();
1131 }
1132 }
1133 Matcher m = new Matcher(this, input);
1134 return m;
1135 }
1136
1137 /**
1138 * Returns this pattern‘s match flags.
1139 *
1140 * @return The match flags specified when this pattern was compiled
1141 */
1142 public int flags() {
1143 return flags0;
1144 }
1145
1146 /**
1147 * Compiles the given regular expression and attempts to match the given
1148 * input against it.
1149 *
1150 * <p> An invocation of this convenience method of the form
1151 *
1152 * <blockquote><pre>
1153 * Pattern.matches(regex, input);</pre></blockquote>
1154 *
1155 * behaves in exactly the same way as the expression
1156 *
1157 * <blockquote><pre>
1158 * Pattern.compile(regex).matcher(input).matches()</pre></blockquote>
1159 *
1160 * <p> If a pattern is to be used multiple times, compiling it once and reusing
1161 * it will be more efficient than invoking this method each time. </p>
1162 *
1163 * @param regex
1164 * The expression to be compiled
1165 *
1166 * @param input
1167 * The character sequence to be matched
1168 * @return whether or not the regular expression matches on the input
1169 * @throws PatternSyntaxException
1170 * If the expression‘s syntax is invalid
1171 */
1172 public static boolean matches(String regex, CharSequence input) {
1173 Pattern p = Pattern.compile(regex);
1174 Matcher m = p.matcher(input);
1175 return m.matches();
1176 }
1177
1178 /**
1179 * Splits the given input sequence around matches of this pattern.
1180 *
1181 * <p> The array returned by this method contains each substring of the
1182 * input sequence that is terminated by another subsequence that matches
1183 * this pattern or is terminated by the end of the input sequence. The
1184 * substrings in the array are in the order in which they occur in the
1185 * input. If this pattern does not match any subsequence of the input then
1186 * the resulting array has just one element, namely the input sequence in
1187 * string form.
1188 *
1189 * <p> When there is a positive-width match at the beginning of the input
1190 * sequence then an empty leading substring is included at the beginning
1191 * of the resulting array. A zero-width match at the beginning however
1192 * never produces such empty leading substring.
1193 *
1194 * <p> The {@code limit} parameter controls the number of times the
1195 * pattern is applied and therefore affects the length of the resulting
1196 * array.
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[] newtemp = new int[j + 3*(pLen-i) + 2];
1682 System.arraycopy(temp, 0, newtemp, 0, j);
1683
1684 boolean inQuote = true;
1685 boolean beginQuote = true;
1686 while (i < pLen) {
1687 int c = temp[i++];
1688 if (!ASCII.isAscii(c) || ASCII.isAlpha(c)) {
1689 newtemp[j++] = c;
1690 } else if (ASCII.isDigit(c)) {
1691 if (beginQuote) {
1692 /*
1693 * A unicode escape \[0xu] could be before this quote,
1694 * and we don‘t want this numeric char to processed as
1695 * part of the escape.
1696 */
1697 newtemp[j++] = ‘\\‘;
1698 newtemp[j++] = ‘x‘;
1699 newtemp[j++] = ‘3‘;
1700 }
1701 newtemp[j++] = c;
1702 } else if (c != ‘\\‘) {
1703 if (inQuote) newtemp[j++] = ‘\\‘;
1704 newtemp[j++] = c;
1705 } else if (inQuote) {
1706 if (temp[i] == ‘E‘) {
1707 i++;
1708 inQuote = false;
1709 } else {
1710 newtemp[j++] = ‘\\‘;
1711 newtemp[j++] = ‘\\‘;
1712 }
1713 } else {
1714 if (temp[i] == ‘Q‘) {
1715 i++;
1716 inQuote = true;
1717 beginQuote = true;
1718 continue;
1719 } else {
1720 newtemp[j++] = c;
1721 if (i != pLen)
1722 newtemp[j++] = temp[i++];
1723 }
1724 }
1725
1726 beginQuote = false;
1727 }
1728
1729 patternLength = j;
1730 temp = Arrays.copyOf(newtemp, j + 2); // double zero termination
1731 }
1732
1733 /**
1734 * Copies regular expression to an int array and invokes the parsing
1735 * of the expression which will create the object tree.
1736 */
1737 private void compile() {
1738 // Handle canonical equivalences
1739 if (has(CANON_EQ) && !has(LITERAL)) {
1740 normalizedPattern = normalize(pattern);
1741 } else {
1742 normalizedPattern = pattern;
1743 }
1744 patternLength = normalizedPattern.length();
1745
1746 // Copy pattern to int array for convenience
1747 // Use double zero to terminate pattern
1748 temp = new int[patternLength + 2];
1749
1750 hasSupplementary = false;
1751 int c, count = 0;
1752 // Convert all chars into code points
1753 for (int x = 0; x < patternLength; x += Character.charCount(c)) {
1754 c = normalizedPattern.codePointAt(x);
1755 if (isSupplementary(c)) {
1756 hasSupplementary = true;
1757 }
1758 temp[count++] = c;
1759 }
1760
1761 patternLength = count; // patternLength now in code points
1762
1763 if (! has(LITERAL))
1764 RemoveQEQuoting();
1765
1766 // Allocate all temporary objects here.
1767 buffer = new int[32];
1768 groupNodes = new GroupHead[10];
1769 namedGroups = null;
1770 topClosureNodes = new ArrayList<>(10);
1771
1772 if (has(LITERAL)) {
1773 // Literal pattern handling
1774 matchRoot = newSlice(temp, patternLength, hasSupplementary);
1775 matchRoot.next = lastAccept;
1776 } else {
1777 // Start recursive descent parsing
1778 matchRoot = expr(lastAccept);
1779 // Check extra pattern characters
1780 if (patternLength != cursor) {
1781 if (peek() == ‘)‘) {
1782 throw error("Unmatched closing ‘)‘");
1783 } else {
1784 throw error("Unexpected internal error");
1785 }
1786 }
1787 }
1788
1789 // Peephole optimization
1790 if (matchRoot instanceof Slice) {
1791 root = BnM.optimize(matchRoot);
1792 if (root == matchRoot) {
1793 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1794 }
1795 } else if (matchRoot instanceof Begin || matchRoot instanceof First) {
1796 root = matchRoot;
1797 } else {
1798 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1799 }
1800
1801 // Optimize the greedy Loop to prevent exponential backtracking, IF there
1802 // is no group ref in this pattern. With a non-negative localTCNCount value,
1803 // the greedy type Loop, Curly will skip the backtracking for any starting
1804 // position "i" that failed in the past.
1805 if (!hasGroupRef) {
1806 for (Node node : topClosureNodes) {
1807 if (node instanceof Loop) {
1808 // non-deterministic-greedy-group
1809 ((Loop)node).posIndex = localTCNCount++;
1810 }
1811 }
1812 }
1813
1814 // Release temporary storage
1815 temp = null;
1816 buffer = null;
1817 groupNodes = null;
1818 patternLength = 0;
1819 compiled = true;
1820 topClosureNodes = null;
1821 }
1822
1823 Map<String, Integer> namedGroups() {
1824 Map<String, Integer> groups = namedGroups;
1825 if (groups == null) {
1826 namedGroups = groups = new HashMap<>(2);
1827 }
1828 return groups;
1829 }
1830
1831 /**
1832 * Used to accumulate information about a subtree of the object graph
1833 * so that optimizations can be applied to the subtree.
1834 */
1835 static final class TreeInfo {
1836 int minLength;
1837 int maxLength;
1838 boolean maxValid;
1839 boolean deterministic;
1840
1841 TreeInfo() {
1842 reset();
1843 }
1844 void reset() {
1845 minLength = 0;
1846 maxLength = 0;
1847 maxValid = true;
1848 deterministic = true;
1849 }
1850 }
1851
1852 /*
1853 * The following private methods are mainly used to improve the
1854 * readability of the code. In order to let the Java compiler easily
1855 * inline them, we should not put many assertions or error checks in them.
1856 */
1857
1858 /**
1859 * Indicates whether a particular flag is set or not.
1860 */
1861 private boolean has(int f) {
1862 return (flags0 & f) != 0;
1863 }
1864
1865 /**
1866 * Match next character, signal error if failed.
1867 */
1868 private void accept(int ch, String s) {
1869 int testChar = temp[cursor++];
1870 if (has(COMMENTS))
1871 testChar = parsePastWhitespace(testChar);
1872 if (ch != testChar) {
1873 throw error(s);
1874 }
1875 }
1876
1877 /**
1878 * Mark the end of pattern with a specific character.
1879 */
1880 private void mark(int c) {
1881 temp[patternLength] = c;
1882 }
1883
1884 /**
1885 * Peek the next character, and do not advance the cursor.
1886 */
1887 private int peek() {
1888 int ch = temp[cursor];
1889 if (has(COMMENTS))
1890 ch = peekPastWhitespace(ch);
1891 return ch;
1892 }
1893
1894 /**
1895 * Read the next character, and advance the cursor by one.
1896 */
1897 private int read() {
1898 int ch = temp[cursor++];
1899 if (has(COMMENTS))
1900 ch = parsePastWhitespace(ch);
1901 return ch;
1902 }
1903
1904 /**
1905 * Read the next character, and advance the cursor by one,
1906 * ignoring the COMMENTS setting
1907 */
1908 private int readEscaped() {
1909 int ch = temp[cursor++];
1910 return ch;
1911 }
1912
1913 /**
1914 * Advance the cursor by one, and peek the next character.
1915 */
1916 private int next() {
1917 int ch = temp[++cursor];
1918 if (has(COMMENTS))
1919 ch = peekPastWhitespace(ch);
1920 return ch;
1921 }
1922
1923 /**
1924 * Advance the cursor by one, and peek the next character,
1925 * ignoring the COMMENTS setting
1926 */
1927 private int nextEscaped() {
1928 int ch = temp[++cursor];
1929 return ch;
1930 }
1931
1932 /**
1933 * If in xmode peek past whitespace and comments.
1934 */
1935 private int peekPastWhitespace(int ch) {
1936 while (ASCII.isSpace(ch) || ch == ‘#‘) {
1937 while (ASCII.isSpace(ch))
1938 ch = temp[++cursor];
1939 if (ch == ‘#‘) {
1940 ch = peekPastLine();
1941 }
1942 }
1943 return ch;
1944 }
1945
1946 /**
1947 * If in xmode parse past whitespace and comments.
1948 */
1949 private int parsePastWhitespace(int ch) {
1950 while (ASCII.isSpace(ch) || ch == ‘#‘) {
1951 while (ASCII.isSpace(ch))
1952 ch = temp[cursor++];
1953 if (ch == ‘#‘)
1954 ch = parsePastLine();
1955 }
1956 return ch;
1957 }
1958
1959 /**
1960 * xmode parse past comment to end of line.
1961 */
1962 private int parsePastLine() {
1963 int ch = temp[cursor++];
1964 while (ch != 0 && !isLineSeparator(ch))
1965 ch = temp[cursor++];
1966 return ch;
1967 }
1968
1969 /**
1970 * xmode peek past comment to end of line.
1971 */
1972 private int peekPastLine() {
1973 int ch = temp[++cursor];
1974 while (ch != 0 && !isLineSeparator(ch))
1975 ch = temp[++cursor];
1976 return ch;
1977 }
1978
1979 /**
1980 * Determines if character is a line separator in the current mode
1981 */
1982 private boolean isLineSeparator(int ch) {
1983 if (has(UNIX_LINES)) {
1984 return ch == ‘\n‘;
1985 } else {
1986 return (ch == ‘\n‘ ||
1987 ch == ‘\r‘ ||
1988 (ch|1) == ‘\u2029‘ ||
1989 ch == ‘\u0085‘);
1990 }
1991 }
1992
1993 /**
1994 * Read the character after the next one, and advance the cursor by two.
1995 */
1996 private int skip() {
1997 int i = cursor;
1998 int ch = temp[i+1];
1999 cursor = i + 2;
2000 return ch;
2001 }
2002
2003 /**
2004 * Unread one next character, and retreat cursor by one.
2005 */
2006 private void unread() {
2007 cursor--;
2008 }
2009
2010 /**
2011 * Internal method used for handling all syntax errors. The pattern is
2012 * displayed with a pointer to aid in locating the syntax error.
2013 */
2014 private PatternSyntaxException error(String s) {
2015 return new PatternSyntaxException(s, normalizedPattern, cursor - 1);
2016 }
2017
2018 /**
2019 * Determines if there is any supplementary character or unpaired
2020 * surrogate in the specified range.
2021 */
2022 private boolean findSupplementary(int start, int end) {
2023 for (int i = start; i < end; i++) {
2024 if (isSupplementary(temp[i]))
2025 return true;
2026 }
2027 return false;
2028 }
2029
2030 /**
2031 * Determines if the specified code point is a supplementary
2032 * character or unpaired surrogate.
2033 */
2034 private static final boolean isSupplementary(int ch) {
2035 return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT ||
2036 Character.isSurrogate((char)ch);
2037 }
2038
2039 /**
2040 * The following methods handle the main parsing. They are sorted
2041 * according to their precedence order, the lowest one first.
2042 */
2043
2044 /**
2045 * The expression is parsed with branch nodes added for alternations.
2046 * This may be called recursively to parse sub expressions that may
2047 * contain alternations.
2048 */
2049 private Node expr(Node end) {
2050 Node prev = null;
2051 Node firstTail = null;
2052 Branch branch = null;
2053 Node branchConn = null;
2054
2055 for (;;) {
2056 Node node = sequence(end);
2057 Node nodeTail = root; //double return
2058 if (prev == null) {
2059 prev = node;
2060 firstTail = nodeTail;
2061 } else {
2062 // Branch
2063 if (branchConn == null) {
2064 branchConn = new BranchConn();
2065 branchConn.next = end;
2066 }
2067 if (node == end) {
2068 // if the node returned from sequence() is "end"
2069 // we have an empty expr, set a null atom into
2070 // the branch to indicate to go "next" directly.
2071 node = null;
2072 } else {
2073 // the "tail.next" of each atom goes to branchConn
2074 nodeTail.next = branchConn;
2075 }
2076 if (prev == branch) {
2077 branch.add(node);
2078 } else {
2079 if (prev == end) {
2080 prev = null;
2081 } else {
2082 // replace the "end" with "branchConn" at its tail.next
2083 // when put the "prev" into the branch as the first atom.
2084 firstTail.next = branchConn;
2085 }
2086 prev = branch = new Branch(prev, node, branchConn);
2087 }
2088 }
2089 if (peek() != ‘|‘) {
2090 return prev;
2091 }
2092 next();
2093 }
2094 }
2095
2096 @SuppressWarnings("fallthrough")
2097 /**
2098 * Parsing of sequences between alternations.
2099 */
2100 private Node sequence(Node end) {
2101 Node head = null;
2102 Node tail = null;
2103 Node node = null;
2104 LOOP:
2105 for (;;) {
2106 int ch = peek();
2107 switch (ch) {
2108 case ‘(‘:
2109 // Because group handles its own closure,
2110 // we need to treat it differently
2111 node = group0();
2112 // Check for comment or flag group
2113 if (node == null)
2114 continue;
2115 if (head == null)
2116 head = node;
2117 else
2118 tail.next = node;
2119 // Double return: Tail was returned in root
2120 tail = root;
2121 continue;
2122 case ‘[‘:
2123 if (has(CANON_EQ) && !has(LITERAL))
2124 node = new NFCCharProperty(clazz(true));
2125 else
2126 node = newCharProperty(clazz(true));
2127 break;
2128 case ‘\\‘:
2129 ch = nextEscaped();
2130 if (ch == ‘p‘ || ch == ‘P‘) {
2131 boolean oneLetter = true;
2132 boolean comp = (ch == ‘P‘);
2133 ch = next(); // Consume { if present
2134 if (ch != ‘{‘) {
2135 unread();
2136 } else {
2137 oneLetter = false;
2138 }
2139 // node = newCharProperty(family(oneLetter, comp));
2140 if (has(CANON_EQ) && !has(LITERAL))
2141 node = new NFCCharProperty(family(oneLetter, comp));
2142 else
2143 node = newCharProperty(family(oneLetter, comp));
2144 } else {
2145 unread();
2146 node = atom();
2147 }
2148 break;
2149 case ‘^‘:
2150 next();
2151 if (has(MULTILINE)) {
2152 if (has(UNIX_LINES))
2153 node = new UnixCaret();
2154 else
2155 node = new Caret();
2156 } else {
2157 node = new Begin();
2158 }
2159 break;
2160 case ‘$‘:
2161 next();
2162 if (has(UNIX_LINES))
2163 node = new UnixDollar(has(MULTILINE));
2164 else
2165 node = new Dollar(has(MULTILINE));
2166 break;
2167 case ‘.‘:
2168 next();
2169 if (has(DOTALL)) {
2170 node = new CharProperty(ALL());
2171 } else {
2172 if (has(UNIX_LINES)) {
2173 node = new CharProperty(UNIXDOT());
2174 } else {
2175 node = new CharProperty(DOT());
2176 }
2177 }
2178 break;
2179 case ‘|‘:
2180 case ‘)‘:
2181 break LOOP;
2182 case ‘]‘: // Now interpreting dangling ] and } as literals
2183 case ‘}‘:
2184 node = atom();
2185 break;
2186 case ‘?‘:
2187 case ‘*‘:
2188 case ‘+‘:
2189 next();
2190 throw error("Dangling meta character ‘" + ((char)ch) + "‘");
2191 case 0:
2192 if (cursor >= patternLength) {
2193 break LOOP;
2194 }
2195 // Fall through
2196 default:
2197 node = atom();
2198 break;
2199 }
2200
2201 node = closure(node);
2202 /* save the top dot-greedy nodes (.*, .+) as well
2203 if (node instanceof GreedyCharProperty &&
2204 ((GreedyCharProperty)node).cp instanceof Dot) {
2205 topClosureNodes.add(node);
2206 }
2207 */
2208 if (head == null) {
2209 head = tail = node;
2210 } else {
2211 tail.next = node;
2212 tail = node;
2213 }
2214 }
2215 if (head == null) {
2216 return end;
2217 }
2218 tail.next = end;
2219 root = tail; //double return
2220 return head;
2221 }
2222
2223 @SuppressWarnings("fallthrough")
2224 /**
2225 * Parse and add a new Single or Slice.
2226 */
2227 private Node atom() {
2228 int first = 0;
2229 int prev = -1;
2230 boolean hasSupplementary = false;
2231 int ch = peek();
2232 for (;;) {
2233 switch (ch) {
2234 case ‘*‘:
2235 case ‘+‘:
2236 case ‘?‘:
2237 case ‘{‘:
2238 if (first > 1) {
2239 cursor = prev; // Unwind one character
2240 first--;
2241 }
2242 break;
2243 case ‘$‘:
2244 case ‘.‘:
2245 case ‘^‘:
2246 case ‘(‘:
2247 case ‘[‘:
2248 case ‘|‘:
2249 case ‘)‘:
2250 break;
2251 case ‘\\‘:
2252 ch = nextEscaped();
2253 if (ch == ‘p‘ || ch == ‘P‘) { // Property
2254 if (first > 0) { // Slice is waiting; handle it first
2255 unread();
2256 break;
2257 } else { // No slice; just return the family node
2258 boolean comp = (ch == ‘P‘);
2259 boolean oneLetter = true;
2260 ch = next(); // Consume { if present
2261 if (ch != ‘{‘)
2262 unread();
2263 else
2264 oneLetter = false;
2265 if (has(CANON_EQ) && !has(LITERAL))
2266 return new NFCCharProperty(family(oneLetter, comp));
2267 else
2268 return newCharProperty(family(oneLetter, comp));
2269 }
2270 }
2271 unread();
2272 prev = cursor;
2273 ch = escape(false, first == 0, false);
2274 if (ch >= 0) {
2275 append(ch, first);
2276 first++;
2277 if (isSupplementary(ch)) {
2278 hasSupplementary = true;
2279 }
2280 ch = peek();
2281 continue;
2282 } else if (first == 0) {
2283 return root;
2284 }
2285 // Unwind meta escape sequence
2286 cursor = prev;
2287 break;
2288 case 0:
2289 if (cursor >= patternLength) {
2290 break;
2291 }
2292 // Fall through
2293 default:
2294 prev = cursor;
2295 append(ch, first);
2296 first++;
2297 if (isSupplementary(ch)) {
2298 hasSupplementary = true;
2299 }
2300 ch = next();
2301 continue;
2302 }
2303 break;
2304 }
2305 if (first == 1) {
2306 return newCharProperty(single(buffer[0]));
2307 } else {
2308 return newSlice(buffer, first, hasSupplementary);
2309 }
2310 }
2311
2312 private void append(int ch, int len) {
2313 if (len >= buffer.length) {
2314 int[] tmp = new int[len+len];
2315 System.arraycopy(buffer, 0, tmp, 0, len);
2316 buffer = tmp;
2317 }
2318 buffer[len] = ch;
2319 }
2320
2321 /**
2322 * Parses a backref greedily, taking as many numbers as it
2323 * can. The first digit is always treated as a backref, but
2324 * multi digit numbers are only treated as a backref if at
2325 * least that many backrefs exist at this point in the regex.
2326 */
2327 private Node ref(int refNum) {
2328 boolean done = false;
2329 while(!done) {
2330 int ch = peek();
2331 switch(ch) {
2332 case ‘0‘:
2333 case ‘1‘:
2334 case ‘2‘:
2335 case ‘3‘:
2336 case ‘4‘:
2337 case ‘5‘:
2338 case ‘6‘:
2339 case ‘7‘:
2340 case ‘8‘:
2341 case ‘9‘:
2342 int newRefNum = (refNum * 10) + (ch - ‘0‘);
2343 // Add another number if it doesn‘t make a group
2344 // that doesn‘t exist
2345 if (capturingGroupCount - 1 < newRefNum) {
2346 done = true;
2347 break;
2348 }
2349 refNum = newRefNum;
2350 read();
2351 break;
2352 default:
2353 done = true;
2354 break;
2355 }
2356 }
2357 hasGroupRef = true;
2358 if (has(CASE_INSENSITIVE))
2359 return new CIBackRef(refNum, has(UNICODE_CASE));
2360 else
2361 return new BackRef(refNum);
2362 }
2363
2364 /**
2365 * Parses an escape sequence to determine the actual value that needs
2366 * to be matched.
2367 * If -1 is returned and create was true a new object was added to the tree
2368 * to handle the escape sequence.
2369 * If the returned value is greater than zero, it is the value that
2370 * matches the escape sequence.
2371 */
2372 private int escape(boolean inclass, boolean create, boolean isrange) {
2373 int ch = skip();
2374 switch (ch) {
2375 case ‘0‘:
2376 return o();
2377 case ‘1‘:
2378 case ‘2‘:
2379 case ‘3‘:
2380 case ‘4‘:
2381 case ‘5‘:
2382 case ‘6‘:
2383 case ‘7‘:
2384 case ‘8‘:
2385 case ‘9‘:
2386 if (inclass) break;
2387 if (create) {
2388 root = ref((ch - ‘0‘));
2389 }
2390 return -1;
2391 case ‘A‘:
2392 if (inclass) break;
2393 if (create) root = new Begin();
2394 return -1;
2395 case ‘B‘:
2396 if (inclass) break;
2397 if (create) root = new Bound(Bound.NONE, has(UNICODE_CHARACTER_CLASS));
2398 return -1;
2399 case ‘C‘:
2400 break;
2401 case ‘D‘:
2402 if (create) {
2403 predicate = has(UNICODE_CHARACTER_CLASS) ?
2404 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2405 predicate = predicate.negate();
2406 if (!inclass)
2407 root = newCharProperty(predicate);
2408 }
2409 return -1;
2410 case ‘E‘:
2411 case ‘F‘:
2412 break;
2413 case ‘G‘:
2414 if (inclass) break;
2415 if (create) root = new LastMatch();
2416 return -1;
2417 case ‘H‘:
2418 if (create) {
2419 predicate = HorizWS().negate();
2420 if (!inclass)
2421 root = newCharProperty(predicate);
2422 }
2423 return -1;
2424 case ‘I‘:
2425 case ‘J‘:
2426 case ‘K‘:
2427 case ‘L‘:
2428 case ‘M‘:
2429 break;
2430 case ‘N‘:
2431 return N();
2432 case ‘O‘:
2433 case ‘P‘:
2434 case ‘Q‘:
2435 break;
2436 case ‘R‘:
2437 if (inclass) break;
2438 if (create) root = new LineEnding();
2439 return -1;
2440 case ‘S‘:
2441 if (create) {
2442 predicate = has(UNICODE_CHARACTER_CLASS) ?
2443 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2444 predicate = predicate.negate();
2445 if (!inclass)
2446 root = newCharProperty(predicate);
2447 }
2448 return -1;
2449 case ‘T‘:
2450 case ‘U‘:
2451 break;
2452 case ‘V‘:
2453 if (create) {
2454 predicate = VertWS().negate();
2455 if (!inclass)
2456 root = newCharProperty(predicate);
2457 }
2458 return -1;
2459 case ‘W‘:
2460 if (create) {
2461 predicate = has(UNICODE_CHARACTER_CLASS) ?
2462 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2463 predicate = predicate.negate();
2464 if (!inclass)
2465 root = newCharProperty(predicate);
2466 }
2467 return -1;
2468 case ‘X‘:
2469 if (inclass) break;
2470 if (create) {
2471 root = new XGrapheme();
2472 }
2473 return -1;
2474 case ‘Y‘:
2475 break;
2476 case ‘Z‘:
2477 if (inclass) break;
2478 if (create) {
2479 if (has(UNIX_LINES))
2480 root = new UnixDollar(false);
2481 else
2482 root = new Dollar(false);
2483 }
2484 return -1;
2485 case ‘a‘:
2486 return ‘\007‘;
2487 case ‘b‘:
2488 if (inclass) break;
2489 if (create) {
2490 if (peek() == ‘{‘) {
2491 if (skip() == ‘g‘) {
2492 if (read() == ‘}‘) {
2493 root = new GraphemeBound();
2494 return -1;
2495 }
2496 break; // error missing trailing }
2497 }
2498 unread(); unread();
2499 }
2500 root = new Bound(Bound.BOTH, has(UNICODE_CHARACTER_CLASS));
2501 }
2502 return -1;
2503 case ‘c‘:
2504 return c();
2505 case ‘d‘:
2506 if (create) {
2507 predicate = has(UNICODE_CHARACTER_CLASS) ?
2508 CharPredicates.DIGIT() : CharPredicates.ASCII_DIGIT();
2509 if (!inclass)
2510 root = newCharProperty(predicate);
2511 }
2512 return -1;
2513 case ‘e‘:
2514 return ‘\033‘;
2515 case ‘f‘:
2516 return ‘\f‘;
2517 case ‘g‘:
2518 break;
2519 case ‘h‘:
2520 if (create) {
2521 predicate = HorizWS();
2522 if (!inclass)
2523 root = newCharProperty(predicate);
2524 }
2525 return -1;
2526 case ‘i‘:
2527 case ‘j‘:
2528 break;
2529 case ‘k‘:
2530 if (inclass)
2531 break;
2532 if (read() != ‘<‘)
2533 throw error("\\k is not followed by ‘<‘ for named capturing group");
2534 String name = groupname(read());
2535 if (!namedGroups().containsKey(name))
2536 throw error("named capturing group <" + name + "> does not exist");
2537 if (create) {
2538 hasGroupRef = true;
2539 if (has(CASE_INSENSITIVE))
2540 root = new CIBackRef(namedGroups().get(name), has(UNICODE_CASE));
2541 else
2542 root = new BackRef(namedGroups().get(name));
2543 }
2544 return -1;
2545 case ‘l‘:
2546 case ‘m‘:
2547 break;
2548 case ‘n‘:
2549 return ‘\n‘;
2550 case ‘o‘:
2551 case ‘p‘:
2552 case ‘q‘:
2553 break;
2554 case ‘r‘:
2555 return ‘\r‘;
2556 case ‘s‘:
2557 if (create) {
2558 predicate = has(UNICODE_CHARACTER_CLASS) ?
2559 CharPredicates.WHITE_SPACE() : CharPredicates.ASCII_SPACE();
2560 if (!inclass)
2561 root = newCharProperty(predicate);
2562 }
2563 return -1;
2564 case ‘t‘:
2565 return ‘\t‘;
2566 case ‘u‘:
2567 return u();
2568 case ‘v‘:
2569 // ‘\v‘ was implemented as VT/0x0B in releases < 1.8 (though
2570 // undocumented). In JDK8 ‘\v‘ is specified as a predefined
2571 // character class for all vertical whitespace characters.
2572 // So [-1, root=VertWS node] pair is returned (instead of a
2573 // single 0x0B). This breaks the range if ‘\v‘ is used as
2574 // the start or end value, such as [\v-...] or [...-\v], in
2575 // which a single definite value (0x0B) is expected. For
2576 // compatibility concern ‘\013‘/0x0B is returned if isrange.
2577 if (isrange)
2578 return ‘\013‘;
2579 if (create) {
2580 predicate = VertWS();
2581 if (!inclass)
2582 root = newCharProperty(predicate);
2583 }
2584 return -1;
2585 case ‘w‘:
2586 if (create) {
2587 predicate = has(UNICODE_CHARACTER_CLASS) ?
2588 CharPredicates.WORD() : CharPredicates.ASCII_WORD();
2589 if (!inclass)
2590 root = newCharProperty(predicate);
2591 }
2592 return -1;
2593 case ‘x‘:
2594 return x();
2595 case ‘y‘:
2596 break;
2597 case ‘z‘:
2598 if (inclass) break;
2599 if (create) root = new End();
2600 return -1;
2601 default:
2602 return ch;
2603 }
2604 throw error("Illegal/unsupported escape sequence");
2605 }
2606
2607 /**
2608 * Parse a character class, and return the node that matches it.
2609 *
2610 * Consumes a ] on the way out if consume is true. Usually consume
2611 * is true except for the case of [abc&&def] where def is a separate
2612 * right hand node with "understood" brackets.
2613 */
2614 private CharPredicate clazz(boolean consume) {
2615 CharPredicate prev = null;
2616 CharPredicate curr = null;
2617 BitClass bits = new BitClass();
2618 BmpCharPredicate bitsP = ch -> ch < 256 && bits.bits[ch];
2619
2620 boolean isNeg = false;
2621 boolean hasBits = false;
2622 int ch = next();
2623
2624 // Negates if first char in a class, otherwise literal
2625 if (ch == ‘^‘ && temp[cursor-1] == ‘[‘) {
2626 ch = next();
2627 isNeg = true;
2628 }
2629 for (;;) {
2630 switch (ch) {
2631 case ‘[‘:
2632 curr = clazz(true);
2633 if (prev == null)
2634 prev = curr;
2635 else
2636 prev = prev.union(curr);
2637 ch = peek();
2638 continue;
2639 case ‘&‘:
2640 ch = next();
2641 if (ch == ‘&‘) {
2642 ch = next();
2643 CharPredicate right = null;
2644 while (ch != ‘]‘ && ch != ‘&‘) {
2645 if (ch == ‘[‘) {
2646 if (right == null)
2647 right = clazz(true);
2648 else
2649 right = right.union(clazz(true));
2650 } else { // abc&&def
2651 unread();
2652 right = clazz(false);
2653 }
2654 ch = peek();
2655 }
2656 if (hasBits) {
2657 // bits used, union has high precedence
2658 if (prev == null) {
2659 prev = curr = bitsP;
2660 } else {
2661 prev = prev.union(bitsP);
2662 }
2663 hasBits = false;
2664 }
2665 if (right != null)
2666 curr = right;
2667 if (prev == null) {
2668 if (right == null)
2669 throw error("Bad class syntax");
2670 else
2671 prev = right;
2672 } else {
2673 prev = prev.and(curr);
2674 }
2675 } else {
2676 // treat as a literal &
2677 unread();
2678 break;
2679 }
2680 continue;
2681 case 0:
2682 if (cursor >= patternLength)
2683 throw error("Unclosed character class");
2684 break;
2685 case ‘]‘:
2686 if (prev != null || hasBits) {
2687 if (consume)
2688 next();
2689 if (prev == null)
2690 prev = bitsP;
2691 else if (hasBits)
2692 prev = prev.union(bitsP);
2693 if (isNeg)
2694 return prev.negate();
2695 return prev;
2696 }
2697 break;
2698 default:
2699 break;
2700 }
2701 curr = range(bits);
2702 if (curr == null) { // the bits used
2703 hasBits = true;
2704 } else {
2705 if (prev == null)
2706 prev = curr;
2707 else if (prev != curr)
2708 prev = prev.union(curr);
2709 }
2710 ch = peek();
2711 }
2712 }
2713
2714 private CharPredicate bitsOrSingle(BitClass bits, int ch) {
2715 /* Bits can only handle codepoints in [u+0000-u+00ff] range.
2716 Use "single" node instead of bits when dealing with unicode
2717 case folding for codepoints listed below.
2718 (1)Uppercase out of range: u+00ff, u+00b5
2719 toUpperCase(u+00ff) -> u+0178
2720 toUpperCase(u+00b5) -> u+039c
2721 (2)LatinSmallLetterLongS u+17f
2722 toUpperCase(u+017f) -> u+0053
2723 (3)LatinSmallLetterDotlessI u+131
2724 toUpperCase(u+0131) -> u+0049
2725 (4)LatinCapitalLetterIWithDotAbove u+0130
2726 toLowerCase(u+0130) -> u+0069
2727 (5)KelvinSign u+212a
2728 toLowerCase(u+212a) ==> u+006B
2729 (6)AngstromSign u+212b
2730 toLowerCase(u+212b) ==> u+00e5
2731 */
2732 if (ch < 256 &&
2733 !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) &&
2734 (ch == 0xff || ch == 0xb5 ||
2735 ch == 0x49 || ch == 0x69 || //I and i
2736 ch == 0x53 || ch == 0x73 || //S and s
2737 ch == 0x4b || ch == 0x6b || //K and k
2738 ch == 0xc5 || ch == 0xe5))) { //A+ring
2739 bits.add(ch, flags0);
2740 return null;
2741 }
2742 return single(ch);
2743 }
2744
2745 /**
2746 * Returns a suitably optimized, single character predicate
2747 */
2748 private CharPredicate single(final int ch) {
2749 if (has(CASE_INSENSITIVE)) {
2750 int lower, upper;
2751 if (has(UNICODE_CASE)) {
2752 upper = Character.toUpperCase(ch);
2753 lower = Character.toLowerCase(upper);
2754 // Unicode case insensitive matches
2755 if (upper != lower)
2756 return SingleU(lower);
2757 } else if (ASCII.isAscii(ch)) {
2758 lower = ASCII.toLower(ch);
2759 upper = ASCII.toUpper(ch);
2760 // Case insensitive matches a given BMP character
2761 if (lower != upper)
2762 return SingleI(lower, upper);
2763 }
2764 }
2765 if (isSupplementary(ch))
2766 return SingleS(ch);
2767 return Single(ch); // Match a given BMP character
2768 }
2769
2770 /**
2771 * Parse a single character or a character range in a character class
2772 * and return its representative node.
2773 */
2774 private CharPredicate range(BitClass bits) {
2775 int ch = peek();
2776 if (ch == ‘\\‘) {
2777 ch = nextEscaped();
2778 if (ch == ‘p‘ || ch == ‘P‘) { // A property
2779 boolean comp = (ch == ‘P‘);
2780 boolean oneLetter = true;
2781 // Consume { if present
2782 ch = next();
2783 if (ch != ‘{‘)
2784 unread();
2785 else
2786 oneLetter = false;
2787 return family(oneLetter, comp);
2788 } else { // ordinary escape
2789 boolean isrange = temp[cursor+1] == ‘-‘;
2790 unread();
2791 ch = escape(true, true, isrange);
2792 if (ch == -1)
2793 return predicate;
2794 }
2795 } else {
2796 next();
2797 }
2798 if (ch >= 0) {
2799 if (peek() == ‘-‘) {
2800 int endRange = temp[cursor+1];
2801 if (endRange == ‘[‘) {
2802 return bitsOrSingle(bits, ch);
2803 }
2804 if (endRange != ‘]‘) {
2805 next();
2806 int m = peek();
2807 if (m == ‘\\‘) {
2808 m = escape(true, false, true);
2809 } else {
2810 next();
2811 }
2812 if (m < ch) {
2813 throw error("Illegal character range");
2814 }
2815 if (has(CASE_INSENSITIVE)) {
2816 if (has(UNICODE_CASE))
2817 return CIRangeU(ch, m);
2818 return CIRange(ch, m);
2819 } else {
2820 return Range(ch, m);
2821 }
2822 }
2823 }
2824 return bitsOrSingle(bits, ch);
2825 }
2826 throw error("Unexpected character ‘"+((char)ch)+"‘");
2827 }
2828
2829 /**
2830 * Parses a Unicode character family and returns its representative node.
2831 */
2832 private CharPredicate family(boolean singleLetter, boolean isComplement) {
2833 next();
2834 String name;
2835 CharPredicate p = null;
2836
2837 if (singleLetter) {
2838 int c = temp[cursor];
2839 if (!Character.isSupplementaryCodePoint(c)) {
2840 name = String.valueOf((char)c);
2841 } else {
2842 name = new String(temp, cursor, 1);
2843 }
2844 read();
2845 } else {
2846 int i = cursor;
2847 mark(‘}‘);
2848 while(read() != ‘}‘) {
2849 }
2850 mark(‘\000‘);
2851 int j = cursor;
2852 if (j > patternLength)
2853 throw error("Unclosed character family");
2854 if (i + 1 >= j)
2855 throw error("Empty character family");
2856 name = new String(temp, i, j-i-1);
2857 }
2858
2859 int i = name.indexOf(‘=‘);
2860 if (i != -1) {
2861 // property construct \p{name=value}
2862 String value = name.substring(i + 1);
2863 name = name.substring(0, i).toLowerCase(Locale.ENGLISH);
2864 switch (name) {
2865 case "sc":
2866 case "script":
2867 p = CharPredicates.forUnicodeScript(value);
2868 break;
2869 case "blk":
2870 case "block":
2871 p = CharPredicates.forUnicodeBlock(value);
2872 break;
2873 case "gc":
2874 case "general_category":
2875 p = CharPredicates.forProperty(value);
2876 break;
2877 default:
2878 break;
2879 }
2880 if (p == null)
2881 throw error("Unknown Unicode property {name=<" + name + ">, "
2882 + "value=<" + value + ">}");
2883
2884 } else {
2885 if (name.startsWith("In")) {
2886 // \p{InBlockName}
2887 p = CharPredicates.forUnicodeBlock(name.substring(2));
2888 } else if (name.startsWith("Is")) {
2889 // \p{IsGeneralCategory} and \p{IsScriptName}
2890 name = name.substring(2);
2891 p = CharPredicates.forUnicodeProperty(name);
2892 if (p == null)
2893 p = CharPredicates.forProperty(name);
2894 if (p == null)
2895 p = CharPredicates.forUnicodeScript(name);
2896 } else {
2897 if (has(UNICODE_CHARACTER_CLASS)) {
2898 p = CharPredicates.forPOSIXName(name);
2899 }
2900 if (p == null)
2901 p = CharPredicates.forProperty(name);
2902 }
2903 if (p == null)
2904 throw error("Unknown character property name {In/Is" + name + "}");
2905 }
2906 if (isComplement) {
2907 // it might be too expensive to detect if a complement of
2908 // CharProperty can match "certain" supplementary. So just
2909 // go with StartS.
2910 hasSupplementary = true;
2911 p = p.negate();
2912 }
2913 return p;
2914 }
2915
2916 private CharProperty newCharProperty(CharPredicate p) {
2917 if (p == null)
2918 return null;
2919 if (p instanceof BmpCharPredicate)
2920 return new BmpCharProperty((BmpCharPredicate)p);
2921 else
2922 return new CharProperty(p);
2923 }
2924
2925 /**
2926 * Parses and returns the name of a "named capturing group", the trailing
2927 * ">" is consumed after parsing.
2928 */
2929 private String groupname(int ch) {
2930 StringBuilder sb = new StringBuilder();
2931 if (!ASCII.isAlpha(ch))
2932 throw error("capturing group name does not start with a Latin letter");
2933 do {
2934 sb.append((char) ch);
2935 } while (ASCII.isAlnum(ch=read()));
2936 if (ch != ‘>‘)
2937 throw error("named capturing group is missing trailing ‘>‘");
2938 return sb.toString();
2939 }
2940
2941 /**
2942 * Parses a group and returns the head node of a set of nodes that process
2943 * the group. Sometimes a double return system is used where the tail is
2944 * returned in root.
2945 */
2946 private Node group0() {
2947 boolean capturingGroup = false;
2948 Node head = null;
2949 Node tail = null;
2950 int save = flags0;
2951 int saveTCNCount = topClosureNodes.size();
2952 root = null;
2953 int ch = next();
2954 if (ch == ‘?‘) {
2955 ch = skip();
2956 switch (ch) {
2957 case ‘:‘: // (?:xxx) pure group
2958 head = createGroup(true);
2959 tail = root;
2960 head.next = expr(tail);
2961 break;
2962 case ‘=‘: // (?=xxx) and (?!xxx) lookahead
2963 case ‘!‘:
2964 head = createGroup(true);
2965 tail = root;
2966 head.next = expr(tail);
2967 if (ch == ‘=‘) {
2968 head = tail = new Pos(head);
2969 } else {
2970 head = tail = new Neg(head);
2971 }
2972 break;
2973 case ‘>‘: // (?>xxx) independent group
2974 head = createGroup(true);
2975 tail = root;
2976 head.next = expr(tail);
2977 head = tail = new Ques(head, Qtype.INDEPENDENT);
2978 break;
2979 case ‘<‘: // (?<xxx) look behind
2980 ch = read();
2981 if (ch != ‘=‘ && ch != ‘!‘) {
2982 // named captured group
2983 String name = groupname(ch);
2984 if (namedGroups().containsKey(name))
2985 throw error("Named capturing group <" + name
2986 + "> is already defined");
2987 capturingGroup = true;
2988 head = createGroup(false);
2989 tail = root;
2990 namedGroups().put(name, capturingGroupCount-1);
2991 head.next = expr(tail);
2992 break;
2993 }
2994 int start = cursor;
2995 head = createGroup(true);
2996 tail = root;
2997 head.next = expr(tail);
2998 tail.next = lookbehindEnd;
2999 TreeInfo info = new TreeInfo();
3000 head.study(info);
3001 if (info.maxValid == false) {
3002 throw error("Look-behind group does not have "
3003 + "an obvious maximum length");
3004 }
3005 boolean hasSupplementary = findSupplementary(start, patternLength);
3006 if (ch == ‘=‘) {
3007 head = tail = (hasSupplementary ?
3008 new BehindS(head, info.maxLength,
3009 info.minLength) :
3010 new Behind(head, info.maxLength,
3011 info.minLength));
3012 } else { // if (ch == ‘!‘)
3013 head = tail = (hasSupplementary ?
3014 new NotBehindS(head, info.maxLength,
3015 info.minLength) :
3016 new NotBehind(head, info.maxLength,
3017 info.minLength));
3018 }
3019 // clear all top-closure-nodes inside lookbehind
3020 if (saveTCNCount < topClosureNodes.size())
3021 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3022 break;
3023 case ‘$‘:
3024 case ‘@‘:
3025 throw error("Unknown group type");
3026 default: // (?xxx:) inlined match flags
3027 unread();
3028 addFlag();
3029 ch = read();
3030 if (ch == ‘)‘) {
3031 return null; // Inline modifier only
3032 }
3033 if (ch != ‘:‘) {
3034 throw error("Unknown inline modifier");
3035 }
3036 head = createGroup(true);
3037 tail = root;
3038 head.next = expr(tail);
3039 break;
3040 }
3041 } else { // (xxx) a regular group
3042 capturingGroup = true;
3043 head = createGroup(false);
3044 tail = root;
3045 head.next = expr(tail);
3046 }
3047
3048 accept(‘)‘, "Unclosed group");
3049 flags0 = save;
3050
3051 // Check for quantifiers
3052 Node node = closure(head);
3053 if (node == head) { // No closure
3054 root = tail;
3055 return node; // Dual return
3056 }
3057 if (head == tail) { // Zero length assertion
3058 root = node;
3059 return node; // Dual return
3060 }
3061
3062 // have group closure, clear all inner closure nodes from the
3063 // top list (no backtracking stopper optimization for inner
3064 if (saveTCNCount < topClosureNodes.size())
3065 topClosureNodes.subList(saveTCNCount, topClosureNodes.size()).clear();
3066
3067 if (node instanceof Ques) {
3068 Ques ques = (Ques) node;
3069 if (ques.type == Qtype.POSSESSIVE) {
3070 root = node;
3071 return node;
3072 }
3073 tail.next = new BranchConn();
3074 tail = tail.next;
3075 if (ques.type == Qtype.GREEDY) {
3076 head = new Branch(head, null, tail);
3077 } else { // Reluctant quantifier
3078 head = new Branch(null, head, tail);
3079 }
3080 root = tail;
3081 return head;
3082 } else if (node instanceof Curly) {
3083 Curly curly = (Curly) node;
3084 if (curly.type == Qtype.POSSESSIVE) {
3085 root = node;
3086 return node;
3087 }
3088 // Discover if the group is deterministic
3089 TreeInfo info = new TreeInfo();
3090 if (head.study(info)) { // Deterministic
3091 GroupTail temp = (GroupTail) tail;
3092 head = root = new GroupCurly(head.next, curly.cmin,
3093 curly.cmax, curly.type,
3094 ((GroupTail)tail).localIndex,
3095 ((GroupTail)tail).groupIndex,
3096 capturingGroup);
3097 return head;
3098 } else { // Non-deterministic
3099 int temp = ((GroupHead) head).localIndex;
3100 Loop loop;
3101 if (curly.type == Qtype.GREEDY) {
3102 loop = new Loop(this.localCount, temp);
3103 // add the max_reps greedy to the top-closure-node list
3104 if (curly.cmax == MAX_REPS)
3105 topClosureNodes.add(loop);
3106 } else { // Reluctant Curly
3107 loop = new LazyLoop(this.localCount, temp);
3108 }
3109 Prolog prolog = new Prolog(loop);
3110 this.localCount += 1;
3111 loop.cmin = curly.cmin;
3112 loop.cmax = curly.cmax;
3113 loop.body = head;
3114 tail.next = loop;
3115 root = loop;
3116 return prolog; // Dual return
3117 }
3118 }
3119 throw error("Internal logic error");
3120 }
3121
3122 /**
3123 * Create group head and tail nodes using double return. If the group is
3124 * created with anonymous true then it is a pure group and should not
3125 * affect group counting.
3126 */
3127 private Node createGroup(boolean anonymous) {
3128 int localIndex = localCount++;
3129 int groupIndex = 0;
3130 if (!anonymous)
3131 groupIndex = capturingGroupCount++;
3132 GroupHead head = new GroupHead(localIndex);
3133 root = new GroupTail(localIndex, groupIndex);
3134
3135 // for debug/print only, head.match does NOT need the "tail" info
3136 head.tail = (GroupTail)root;
3137
3138 if (!anonymous && groupIndex < 10)
3139 groupNodes[groupIndex] = head;
3140 return head;
3141 }
3142
3143 @SuppressWarnings("fallthrough")
3144 /**
3145 * Parses inlined match flags and set them appropriately.
3146 */
3147 private void addFlag() {
3148 int ch = peek();
3149 for (;;) {
3150 switch (ch) {
3151 case ‘i‘:
3152 flags0 |= CASE_INSENSITIVE;
3153 break;
3154 case ‘m‘:
3155 flags0 |= MULTILINE;
3156 break;
3157 case ‘s‘:
3158 flags0 |= DOTALL;
3159 break;
3160 case ‘d‘:
3161 flags0 |= UNIX_LINES;
3162 break;
3163 case ‘u‘:
3164 flags0 |= UNICODE_CASE;
3165 break;
3166 case ‘c‘:
3167 flags0 |= CANON_EQ;
3168 break;
3169 case ‘x‘:
3170 flags0 |= COMMENTS;
3171 break;
3172 case ‘U‘:
3173 flags0 |= (UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3174 break;
3175 case ‘-‘: // subFlag then fall through
3176 ch = next();
3177 subFlag();
3178 default:
3179 return;
3180 }
3181 ch = next();
3182 }
3183 }
3184
3185 @SuppressWarnings("fallthrough")
3186 /**
3187 * Parses the second part of inlined match flags and turns off
3188 * flags appropriately.
3189 */
3190 private void subFlag() {
3191 int ch = peek();
3192 for (;;) {
3193 switch (ch) {
3194 case ‘i‘:
3195 flags0 &= ~CASE_INSENSITIVE;
3196 break;
3197 case ‘m‘:
3198 flags0 &= ~MULTILINE;
3199 break;
3200 case ‘s‘:
3201 flags0 &= ~DOTALL;
3202 break;
3203 case ‘d‘:
3204 flags0 &= ~UNIX_LINES;
3205 break;
3206 case ‘u‘:
3207 flags0 &= ~UNICODE_CASE;
3208 break;
3209 case ‘c‘:
3210 flags0 &= ~CANON_EQ;
3211 break;
3212 case ‘x‘:
3213 flags0 &= ~COMMENTS;
3214 break;
3215 case ‘U‘:
3216 flags0 &= ~(UNICODE_CHARACTER_CLASS | UNICODE_CASE);
3217 break;
3218 default:
3219 return;
3220 }
3221 ch = next();
3222 }
3223 }
3224
3225 static final int MAX_REPS = 0x7FFFFFFF;
3226
3227 static enum Qtype {
3228 GREEDY, LAZY, POSSESSIVE, INDEPENDENT
3229 }
3230
3231 private Node curly(Node prev, int cmin) {
3232 int ch = next();
3233 if (ch == ‘?‘) {
3234 next();
3235 return new Curly(prev, cmin, MAX_REPS, Qtype.LAZY);
3236 } else if (ch == ‘+‘) {
3237 next();
3238 return new Curly(prev, cmin, MAX_REPS, Qtype.POSSESSIVE);
3239 }
3240 if (prev instanceof BmpCharProperty) {
3241 return new BmpCharPropertyGreedy((BmpCharProperty)prev, cmin);
3242 } else if (prev instanceof CharProperty) {
3243 return new CharPropertyGreedy((CharProperty)prev, cmin);
3244 }
3245 return new Curly(prev, cmin, MAX_REPS, Qtype.GREEDY);
3246 }
3247
3248 /**
3249 * Processes repetition. If the next character peeked is a quantifier
3250 * then new nodes must be appended to handle the repetition.
3251 * Prev could be a single or a group, so it could be a chain of nodes.
3252 */
3253 private Node closure(Node prev) {
3254 Node atom;
3255 int ch = peek();
3256 switch (ch) {
3257 case ‘?‘:
3258 ch = next();
3259 if (ch == ‘?‘) {
3260 next();
3261 return new Ques(prev, Qtype.LAZY);
3262 } else if (ch == ‘+‘) {
3263 next();
3264 return new Ques(prev, Qtype.POSSESSIVE);
3265 }
3266 return new Ques(prev, Qtype.GREEDY);
3267 case ‘*‘:
3268 return curly(prev, 0);
3269 case ‘+‘:
3270 return curly(prev, 1);
3271 case ‘{‘:
3272 ch = temp[cursor+1];
3273 if (ASCII.isDigit(ch)) {
3274 skip();
3275 int cmin = 0;
3276 do {
3277 cmin = cmin * 10 + (ch - ‘0‘);
3278 } while (ASCII.isDigit(ch = read()));
3279 int cmax = cmin;
3280 if (ch == ‘,‘) {
3281 ch = read();
3282 cmax = MAX_REPS;
3283 if (ch != ‘}‘) {
3284 cmax = 0;
3285 while (ASCII.isDigit(ch)) {
3286 cmax = cmax * 10 + (ch - ‘0‘);
3287 ch = read();
3288 }
3289 }
3290 }
3291 if (ch != ‘}‘)
3292 throw error("Unclosed counted closure");
3293 if (((cmin) | (cmax) | (cmax - cmin)) < 0)
3294 throw error("Illegal repetition range");
3295 Curly curly;
3296 ch = peek();
3297 if (ch == ‘?‘) {
3298 next();
3299 curly = new Curly(prev, cmin, cmax, Qtype.LAZY);
3300 } else if (ch == ‘+‘) {
3301 next();
3302 curly = new Curly(prev, cmin, cmax, Qtype.POSSESSIVE);
3303 } else {
3304 curly = new Curly(prev, cmin, cmax, Qtype.GREEDY);
3305 }
3306 return curly;
3307 } else {
3308 throw error("Illegal repetition");
3309 }
3310 default:
3311 return prev;
3312 }
3313 }
3314
3315 /**
3316 * Utility method for parsing control escape sequences.
3317 */
3318 private int c() {
3319 if (cursor < patternLength) {
3320 return read() ^ 64;
3321 }
3322 throw error("Illegal control escape sequence");
3323 }
3324
3325 /**
3326 * Utility method for parsing octal escape sequences.
3327 */
3328 private int o() {
3329 int n = read();
3330 if (((n-‘0‘)|(‘7‘-n)) >= 0) {
3331 int m = read();
3332 if (((m-‘0‘)|(‘7‘-m)) >= 0) {
3333 int o = read();
3334 if ((((o-‘0‘)|(‘7‘-o)) >= 0) && (((n-‘0‘)|(‘3‘-n)) >= 0)) {
3335 return (n - ‘0‘) * 64 + (m - ‘0‘) * 8 + (o - ‘0‘);
3336 }
3337 unread();
3338 return (n - ‘0‘) * 8 + (m - ‘0‘);
3339 }
3340 unread();
3341 return (n - ‘0‘);
3342 }
3343 throw error("Illegal octal escape sequence");
3344 }
3345
3346 /**
3347 * Utility method for parsing hexadecimal escape sequences.
3348 */
3349 private int x() {
3350 int n = read();
3351 if (ASCII.isHexDigit(n)) {
3352 int m = read();
3353 if (ASCII.isHexDigit(m)) {
3354 return ASCII.toDigit(n) * 16 + ASCII.toDigit(m);
3355 }
3356 } else if (n == ‘{‘ && ASCII.isHexDigit(peek())) {
3357 int ch = 0;
3358 while (ASCII.isHexDigit(n = read())) {
3359 ch = (ch << 4) + ASCII.toDigit(n);
3360 if (ch > Character.MAX_CODE_POINT)
3361 throw error("Hexadecimal codepoint is too big");
3362 }
3363 if (n != ‘}‘)
3364 throw error("Unclosed hexadecimal escape sequence");
3365 return ch;
3366 }
3367 throw error("Illegal hexadecimal escape sequence");
3368 }
3369
3370 /**
3371 * Utility method for parsing unicode escape sequences.
3372 */
3373 private int cursor() {
3374 return cursor;
3375 }
3376
3377 private void setcursor(int pos) {
3378 cursor = pos;
3379 }
3380
3381 private int uxxxx() {
3382 int n = 0;
3383 for (int i = 0; i < 4; i++) {
3384 int ch = read();
3385 if (!ASCII.isHexDigit(ch)) {
3386 throw error("Illegal Unicode escape sequence");
3387 }
3388 n = n * 16 + ASCII.toDigit(ch);
3389 }
3390 return n;
3391 }
3392
3393 private int u() {
3394 int n = uxxxx();
3395 if (Character.isHighSurrogate((char)n)) {
3396 int cur = cursor();
3397 if (read() == ‘\\‘ && read() == ‘u‘) {
3398 int n2 = uxxxx();
3399 if (Character.isLowSurrogate((char)n2))
3400 return Character.toCodePoint((char)n, (char)n2);
3401 }
3402 setcursor(cur);
3403 }
3404 return n;
3405 }
3406
3407 private int N() {
3408 if (read() == ‘{‘) {
3409 int i = cursor;
3410 while (cursor < patternLength && read() != ‘}‘) {}
3411 if (cursor > patternLength)
3412 throw error("Unclosed character name escape sequence");
3413 String name = new String(temp, i, cursor - i - 1);
3414 try {
3415 return Character.codePointOf(name);
3416 } catch (IllegalArgumentException x) {
3417 throw error("Unknown character name [" + name + "]");
3418 }
3419 }
3420 throw error("Illegal character name escape sequence");
3421 }
3422
3423 //
3424 // Utility methods for code point support
3425 //
3426 private static final int countChars(CharSequence seq, int index,
3427 int lengthInCodePoints) {
3428 // optimization
3429 if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) {
3430 assert (index >= 0 && index < seq.length());
3431 return 1;
3432 }
3433 int length = seq.length();
3434 int x = index;
3435 if (lengthInCodePoints >= 0) {
3436 assert (index >= 0 && index < length);
3437 for (int i = 0; x < length && i < lengthInCodePoints; i++) {
3438 if (Character.isHighSurrogate(seq.charAt(x++))) {
3439 if (x < length && Character.isLowSurrogate(seq.charAt(x))) {
3440 x++;
3441 }
3442 }
3443 }
3444 return x - index;
3445 }
3446
3447 assert (index >= 0 && index <= length);
3448 if (index == 0) {
3449 return 0;
3450 }
3451 int len = -lengthInCodePoints;
3452 for (int i = 0; x > 0 && i < len; i++) {
3453 if (Character.isLowSurrogate(seq.charAt(--x))) {
3454 if (x > 0 && Character.isHighSurrogate(seq.charAt(x-1))) {
3455 x--;
3456 }
3457 }
3458 }
3459 return index - x;
3460 }
3461
3462 private static final int countCodePoints(CharSequence seq) {
3463 int length = seq.length();
3464 int n = 0;
3465 for (int i = 0; i < length; ) {
3466 n++;
3467 if (Character.isHighSurrogate(seq.charAt(i++))) {
3468 if (i < length && Character.isLowSurrogate(seq.charAt(i))) {
3469 i++;
3470 }
3471 }
3472 }
3473 return n;
3474 }
3475
3476 /**
3477 * Creates a bit vector for matching Latin-1 values. A normal BitClass
3478 * never matches values above Latin-1, and a complemented BitClass always
3479 * matches values above Latin-1.
3480 */
3481 static final class BitClass extends BmpCharProperty {
3482 final boolean[] bits;
3483 BitClass() {
3484 this(new boolean[256]);
3485 }
3486 private BitClass(boolean[] bits) {
3487 super( ch -> ch < 256 && bits[ch]);
3488 this.bits = bits;
3489 }
3490 BitClass add(int c, int flags) {
3491 assert c >= 0 && c <= 255;
3492 if ((flags & CASE_INSENSITIVE) != 0) {
3493 if (ASCII.isAscii(c)) {
3494 bits[ASCII.toUpper(c)] = true;
3495 bits[ASCII.toLower(c)] = true;
3496 } else if ((flags & UNICODE_CASE) != 0) {
3497 bits[Character.toLowerCase(c)] = true;
3498 bits[Character.toUpperCase(c)] = true;
3499 }
3500 }
3501 bits[c] = true;
3502 return this;
3503 }
3504 }
3505
3506 /**
3507 * Utility method for creating a string slice matcher.
3508 */
3509 private Node newSlice(int[] buf, int count, boolean hasSupplementary) {
3510 int[] tmp = new int[count];
3511 if (has(CASE_INSENSITIVE)) {
3512 if (has(UNICODE_CASE)) {
3513 for (int i = 0; i < count; i++) {
3514 tmp[i] = Character.toLowerCase(
3515 Character.toUpperCase(buf[i]));
3516 }
3517 return hasSupplementary? new SliceUS(tmp) : new SliceU(tmp);
3518 }
3519 for (int i = 0; i < count; i++) {
3520 tmp[i] = ASCII.toLower(buf[i]);
3521 }
3522 return hasSupplementary? new SliceIS(tmp) : new SliceI(tmp);
3523 }
3524 for (int i = 0; i < count; i++) {
3525 tmp[i] = buf[i];
3526 }
3527 return hasSupplementary ? new SliceS(tmp) : new Slice(tmp);
3528 }
3529
3530 /**
3531 * The following classes are the building components of the object
3532 * tree that represents a compiled regular expression. The object tree
3533 * is made of individual elements that handle constructs in the Pattern.
3534 * Each type of object knows how to match its equivalent construct with
3535 * the match() method.
3536 */
3537
3538 /**
3539 * Base class for all node classes. Subclasses should override the match()
3540 * method as appropriate. This class is an accepting node, so its match()
3541 * always returns true.
3542 */
3543 static class Node extends Object {
3544 Node next;
3545 Node() {
3546 next = Pattern.accept;
3547 }
3548 /**
3549 * This method implements the classic accept node.
3550 */
3551 boolean match(Matcher matcher, int i, CharSequence seq) {
3552 matcher.last = i;
3553 matcher.groups[0] = matcher.first;
3554 matcher.groups[1] = matcher.last;
3555 return true;
3556 }
3557 /**
3558 * This method is good for all zero length assertions.
3559 */
3560 boolean study(TreeInfo info) {
3561 if (next != null) {
3562 return next.study(info);
3563 } else {
3564 return info.deterministic;
3565 }
3566 }
3567 }
3568
3569 static class LastNode extends Node {
3570 /**
3571 * This method implements the classic accept node with
3572 * the addition of a check to see if the match occurred
3573 * using all of the input.
3574 */
3575 boolean match(Matcher matcher, int i, CharSequence seq) {
3576 if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to)
3577 return false;
3578 matcher.last = i;
3579 matcher.groups[0] = matcher.first;
3580 matcher.groups[1] = matcher.last;
3581 return true;
3582 }
3583 }
3584
3585 /**
3586 * Used for REs that can start anywhere within the input string.
3587 * This basically tries to match repeatedly at each spot in the
3588 * input string, moving forward after each try. An anchored search
3589 * or a BnM will bypass this node completely.
3590 */
3591 static class Start extends Node {
3592 int minLength;
3593 Start(Node node) {
3594 this.next = node;
3595 TreeInfo info = new TreeInfo();
3596 next.study(info);
3597 minLength = info.minLength;
3598 }
3599 boolean match(Matcher matcher, int i, CharSequence seq) {
3600 if (i > matcher.to - minLength) {
3601 matcher.hitEnd = true;
3602 return false;
3603 }
3604 int guard = matcher.to - minLength;
3605 for (; i <= guard; i++) {
3606 if (next.match(matcher, i, seq)) {
3607 matcher.first = i;
3608 matcher.groups[0] = matcher.first;
3609 matcher.groups[1] = matcher.last;
3610 return true;
3611 }
3612 }
3613 matcher.hitEnd = true;
3614 return false;
3615 }
3616 boolean study(TreeInfo info) {
3617 next.study(info);
3618 info.maxValid = false;
3619 info.deterministic = false;
3620 return false;
3621 }
3622 }
3623
3624 /*
3625 * StartS supports supplementary characters, including unpaired surrogates.
3626 */
3627 static final class StartS extends Start {
3628 StartS(Node node) {
3629 super(node);
3630 }
3631 boolean match(Matcher matcher, int i, CharSequence seq) {
3632 if (i > matcher.to - minLength) {
3633 matcher.hitEnd = true;
3634 return false;
3635 }
3636 int guard = matcher.to - minLength;
3637 while (i <= guard) {
3638 //if ((ret = next.match(matcher, i, seq)) || i == guard)
3639 if (next.match(matcher, i, seq)) {
3640 matcher.first = i;
3641 matcher.groups[0] = matcher.first;
3642 matcher.groups[1] = matcher.last;
3643 return true;
3644 }
3645 if (i == guard)
3646 break;
3647 // Optimization to move to the next character. This is
3648 // faster than countChars(seq, i, 1).
3649 if (Character.isHighSurrogate(seq.charAt(i++))) {
3650 if (i < seq.length() &&
3651 Character.isLowSurrogate(seq.charAt(i))) {
3652 i++;
3653 }
3654 }
3655 }
3656 matcher.hitEnd = true;
3657 return false;
3658 }
3659 }
3660
3661 /**
3662 * Node to anchor at the beginning of input. This object implements the
3663 * match for a \A sequence, and the caret anchor will use this if not in
3664 * multiline mode.
3665 */
3666 static final class Begin extends Node {
3667 boolean match(Matcher matcher, int i, CharSequence seq) {
3668 int fromIndex = (matcher.anchoringBounds) ?
3669 matcher.from : 0;
3670 if (i == fromIndex && next.match(matcher, i, seq)) {
3671 matcher.first = i;
3672 matcher.groups[0] = i;
3673 matcher.groups[1] = matcher.last;
3674 return true;
3675 } else {
3676 return false;
3677 }
3678 }
3679 }
3680
3681 /**
3682 * Node to anchor at the end of input. This is the absolute end, so this
3683 * should not match at the last newline before the end as $ will.
3684 */
3685 static final class End extends Node {
3686 boolean match(Matcher matcher, int i, CharSequence seq) {
3687 int endIndex = (matcher.anchoringBounds) ?
3688 matcher.to : matcher.getTextLength();
3689 if (i == endIndex) {
3690 matcher.hitEnd = true;
3691 return next.match(matcher, i, seq);
3692 }
3693 return false;
3694 }
3695 }
3696
3697 /**
3698 * Node to anchor at the beginning of a line. This is essentially the
3699 * object to match for the multiline ^.
3700 */
3701 static final class Caret extends Node {
3702 boolean match(Matcher matcher, int i, CharSequence seq) {
3703 int startIndex = matcher.from;
3704 int endIndex = matcher.to;
3705 if (!matcher.anchoringBounds) {
3706 startIndex = 0;
3707 endIndex = matcher.getTextLength();
3708 }
3709 // Perl does not match ^ at end of input even after newline
3710 if (i == endIndex) {
3711 matcher.hitEnd = true;
3712 return false;
3713 }
3714 if (i > startIndex) {
3715 char ch = seq.charAt(i-1);
3716 if (ch != ‘\n‘ && ch != ‘\r‘
3717 && (ch|1) != ‘\u2029‘
3718 && ch != ‘\u0085‘ ) {
3719 return false;
3720 }
3721 // Should treat /r/n as one newline
3722 if (ch == ‘\r‘ && seq.charAt(i) == ‘\n‘)
3723 return false;
3724 }
3725 return next.match(matcher, i, seq);
3726 }
3727 }
3728
3729 /**
3730 * Node to anchor at the beginning of a line when in unixdot mode.
3731 */
3732 static final class UnixCaret extends Node {
3733 boolean match(Matcher matcher, int i, CharSequence seq) {
3734 int startIndex = matcher.from;
3735 int endIndex = matcher.to;
3736 if (!matcher.anchoringBounds) {
3737 startIndex = 0;
3738 endIndex = matcher.getTextLength();
3739 }
3740 // Perl does not match ^ at end of input even after newline
3741 if (i == endIndex) {
3742 matcher.hitEnd = true;
3743 return false;
3744 }
3745 if (i > startIndex) {
3746 char ch = seq.charAt(i-1);
3747 if (ch != ‘\n‘) {
3748 return false;
3749 }
3750 }
3751 return next.match(matcher, i, seq);
3752 }
3753 }
3754
3755 /**
3756 * Node to match the location where the last match ended.
3757 * This is used for the \G construct.
3758 */
3759 static final class LastMatch extends Node {
3760 boolean match(Matcher matcher, int i, CharSequence seq) {
3761 if (i != matcher.oldLast)
3762 return false;
3763 return next.match(matcher, i, seq);
3764 }
3765 }
3766
3767 /**
3768 * Node to anchor at the end of a line or the end of input based on the
3769 * multiline mode.
3770 *
3771 * When not in multiline mode, the $ can only match at the very end
3772 * of the input, unless the input ends in a line terminator in which
3773 * it matches right before the last line terminator.
3774 *
3775 * Note that \r\n is considered an atomic line terminator.
3776 *
3777 * Like ^ the $ operator matches at a position, it does not match the
3778 * line terminators themselves.
3779 */
3780 static final class Dollar extends Node {
3781 boolean multiline;
3782 Dollar(boolean mul) {
3783 multiline = mul;
3784 }
3785 boolean match(Matcher matcher, int i, CharSequence seq) {
3786 int endIndex = (matcher.anchoringBounds) ?
3787 matcher.to : matcher.getTextLength();
3788 if (!multiline) {
3789 if (i < endIndex - 2)
3790 return false;
3791 if (i == endIndex - 2) {
3792 char ch = seq.charAt(i);
3793 if (ch != ‘\r‘)
3794 return false;
3795 ch = seq.charAt(i + 1);
3796 if (ch != ‘\n‘)
3797 return false;
3798 }
3799 }
3800 // Matches before any line terminator; also matches at the
3801 // end of input
3802 // Before line terminator:
3803 // If multiline, we match here no matter what
3804 // If not multiline, fall through so that the end
3805 // is marked as hit; this must be a /r/n or a /n
3806 // at the very end so the end was hit; more input
3807 // could make this not match here
3808 if (i < endIndex) {
3809 char ch = seq.charAt(i);
3810 if (ch == ‘\n‘) {
3811 // No match between \r\n
3812 if (i > 0 && seq.charAt(i-1) == ‘\r‘)
3813 return false;
3814 if (multiline)
3815 return next.match(matcher, i, seq);
3816 } else if (ch == ‘\r‘ || ch == ‘\u0085‘ ||
3817 (ch|1) == ‘\u2029‘) {
3818 if (multiline)
3819 return next.match(matcher, i, seq);
3820 } else { // No line terminator, no match
3821 return false;
3822 }
3823 }
3824 // Matched at current end so hit end
3825 matcher.hitEnd = true;
3826 // If a $ matches because of end of input, then more input
3827 // could cause it to fail!
3828 matcher.requireEnd = true;
3829 return next.match(matcher, i, seq);
3830 }
3831 boolean study(TreeInfo info) {
3832 next.study(info);
3833 return info.deterministic;
3834 }
3835 }
3836
3837 /**
3838 * Node to anchor at the end of a line or the end of input based on the
3839 * multiline mode when in unix lines mode.
3840 */
3841 static final class UnixDollar extends Node {
3842 boolean multiline;
3843 UnixDollar(boolean mul) {
3844 multiline = mul;
3845 }
3846 boolean match(Matcher matcher, int i, CharSequence seq) {
3847 int endIndex = (matcher.anchoringBounds) ?
3848 matcher.to : matcher.getTextLength();
3849 if (i < endIndex) {
3850 char ch = seq.charAt(i);
3851 if (ch == ‘\n‘) {
3852 // If not multiline, then only possible to
3853 // match at very end or one before end
3854 if (multiline == false && i != endIndex - 1)
3855 return false;
3856 // If multiline return next.match without setting
3857 // matcher.hitEnd
3858 if (multiline)
3859 return next.match(matcher, i, seq);
3860 } else {
3861 return false;
3862 }
3863 }
3864 // Matching because at the end or 1 before the end;
3865 // more input could change this so set hitEnd
3866 matcher.hitEnd = true;
3867 // If a $ matches because of end of input, then more input
3868 // could cause it to fail!
3869 matcher.requireEnd = true;
3870 return next.match(matcher, i, seq);
3871 }
3872 boolean study(TreeInfo info) {
3873 next.study(info);
3874 return info.deterministic;
3875 }
3876 }
3877
3878 /**
3879 * Node class that matches a Unicode line ending ‘\R‘
3880 */
3881 static final class LineEnding extends Node {
3882 boolean match(Matcher matcher, int i, CharSequence seq) {
3883 // (u+000Du+000A|[u+000Au+000Bu+000Cu+000Du+0085u+2028u+2029])
3884 if (i < matcher.to) {
3885 int ch = seq.charAt(i);
3886 if (ch == 0x0A || ch == 0x0B || ch == 0x0C ||
3887 ch == 0x85 || ch == 0x2028 || ch == 0x2029)
3888 return next.match(matcher, i + 1, seq);
3889 if (ch == 0x0D) {
3890 i++;
3891 if (i < matcher.to) {
3892 if (seq.charAt(i) == 0x0A &&
3893 next.match(matcher, i + 1, seq)) {
3894 return true;
3895 }
3896 } else {
3897 matcher.hitEnd = true;
3898 }
3899 return next.match(matcher, i, seq);
3900 }
3901 } else {
3902 matcher.hitEnd = true;
3903 }
3904 return false;
3905 }
3906 boolean study(TreeInfo info) {
3907 info.minLength++;
3908 info.maxLength += 2;
3909 return next.study(info);
3910 }
3911 }
3912
3913 /**
3914 * Abstract node class to match one character satisfying some
3915 * boolean property.
3916 */
3917 static class CharProperty extends Node {
3918 CharPredicate predicate;
3919
3920 CharProperty (CharPredicate predicate) {
3921 this.predicate = predicate;
3922 }
3923 boolean match(Matcher matcher, int i, CharSequence seq) {
3924 if (i < matcher.to) {
3925 int ch = Character.codePointAt(seq, i);
3926 return predicate.is(ch) &&
3927 next.match(matcher, i + Character.charCount(ch), seq);
3928 } else {
3929 matcher.hitEnd = true;
3930 return false;
3931 }
3932 }
3933 boolean study(TreeInfo info) {
3934 info.minLength++;
3935 info.maxLength++;
3936 return next.study(info);
3937 }
3938 }
3939
3940 /**
3941 * Optimized version of CharProperty that works only for
3942 * properties never satisfied by Supplementary characters.
3943 */
3944 private static class BmpCharProperty extends CharProperty {
3945 BmpCharProperty (BmpCharPredicate predicate) {
3946 super(predicate);
3947 }
3948 boolean match(Matcher matcher, int i, CharSequence seq) {
3949 if (i < matcher.to) {
3950 return predicate.is(seq.charAt(i)) &&
3951 next.match(matcher, i + 1, seq);
3952 } else {
3953 matcher.hitEnd = true;
3954 return false;
3955 }
3956 }
3957 }
3958
3959 private static class NFCCharProperty extends Node {
3960 CharPredicate predicate;
3961 NFCCharProperty (CharPredicate predicate) {
3962 this.predicate = predicate;
3963 }
3964
3965 boolean match(Matcher matcher, int i, CharSequence seq) {
3966 if (i < matcher.to) {
3967 int ch0 = Character.codePointAt(seq, i);
3968 int n = Character.charCount(ch0);
3969 int j = i + n;
3970 while (j < matcher.to) {
3971 int ch1 = Character.codePointAt(seq, j);
3972 if (Grapheme.isBoundary(ch0, ch1))
3973 break;
3974 ch0 = ch1;
3975 j += Character.charCount(ch1);
3976 }
3977 if (i + n == j) { // single, assume nfc cp
3978 if (predicate.is(ch0))
3979 return next.match(matcher, j, seq);
3980 } else {
3981 while (i + n < j) {
3982 String nfc = Normalizer.normalize(
3983 seq.toString().substring(i, j), Normalizer.Form.NFC);
3984 if (nfc.codePointCount(0, nfc.length()) == 1) {
3985 if (predicate.is(nfc.codePointAt(0)) &&
3986 next.match(matcher, j, seq)) {
3987 return true;
3988 }
3989 }
3990
3991 ch0 = Character.codePointBefore(seq, j);
3992 j -= Character.charCount(ch0);
3993 }
3994 }
3995 if (j < matcher.to)
3996 return false;
3997 }
3998 matcher.hitEnd = true;
3999 return false;
4000 }
4001
4002 boolean study(TreeInfo info) {
4003 info.minLength++;
4004 info.deterministic = false;
4005 return next.study(info);
4006 }
4007 }
4008
4009 /**
4010 * Node class that matches an unicode extended grapheme cluster
4011 */
4012 static class XGrapheme extends Node {
4013 boolean match(Matcher matcher, int i, CharSequence seq) {
4014 if (i < matcher.to) {
4015 int ch0 = Character.codePointAt(seq, i);
4016 i += Character.charCount(ch0);
4017 while (i < matcher.to) {
4018 int ch1 = Character.codePointAt(seq, i);
4019 if (Grapheme.isBoundary(ch0, ch1))
4020 break;
4021 ch0 = ch1;
4022 i += Character.charCount(ch1);
4023 }
4024 return next.match(matcher, i, seq);
4025 }
4026 matcher.hitEnd = true;
4027 return false;
4028 }
4029
4030 boolean study(TreeInfo info) {
4031 info.minLength++;
4032 info.deterministic = false;
4033 return next.study(info);
4034 }
4035 }
4036
4037 /**
4038 * Node class that handles grapheme boundaries
4039 */
4040 static class GraphemeBound extends Node {
4041 boolean match(Matcher matcher, int i, CharSequence seq) {
4042 int startIndex = matcher.from;
4043 int endIndex = matcher.to;
4044 if (matcher.transparentBounds) {
4045 startIndex = 0;
4046 endIndex = matcher.getTextLength();
4047 }
4048 if (i == startIndex) {
4049 return next.match(matcher, i, seq);
4050 }
4051 if (i < endIndex) {
4052 if (Character.isSurrogatePair(seq.charAt(i-1), seq.charAt(i)) ||
4053 !Grapheme.isBoundary(Character.codePointBefore(seq, i),
4054 Character.codePointAt(seq, i))) {
4055 return false;
4056 }
4057 } else {
4058 matcher.hitEnd = true;
4059 matcher.requireEnd = true;
4060 }
4061 return next.match(matcher, i, seq);
4062 }
4063 }
4064
4065 /**
4066 * Base class for all Slice nodes
4067 */
4068 static class SliceNode extends Node {
4069 int[] buffer;
4070 SliceNode(int[] buf) {
4071 buffer = buf;
4072 }
4073 boolean study(TreeInfo info) {
4074 info.minLength += buffer.length;
4075 info.maxLength += buffer.length;
4076 return next.study(info);
4077 }
4078 }
4079
4080 /**
4081 * Node class for a case sensitive/BMP-only sequence of literal
4082 * characters.
4083 */
4084 static class Slice extends SliceNode {
4085 Slice(int[] buf) {
4086 super(buf);
4087 }
4088 boolean match(Matcher matcher, int i, CharSequence seq) {
4089 int[] buf = buffer;
4090 int len = buf.length;
4091 for (int j=0; j<len; j++) {
4092 if ((i+j) >= matcher.to) {
4093 matcher.hitEnd = true;
4094 return false;
4095 }
4096 if (buf[j] != seq.charAt(i+j))
4097 return false;
4098 }
4099 return next.match(matcher, i+len, seq);
4100 }
4101 }
4102
4103 /**
4104 * Node class for a case_insensitive/BMP-only sequence of literal
4105 * characters.
4106 */
4107 static class SliceI extends SliceNode {
4108 SliceI(int[] buf) {
4109 super(buf);
4110 }
4111 boolean match(Matcher matcher, int i, CharSequence seq) {
4112 int[] buf = buffer;
4113 int len = buf.length;
4114 for (int j=0; j<len; j++) {
4115 if ((i+j) >= matcher.to) {
4116 matcher.hitEnd = true;
4117 return false;
4118 }
4119 int c = seq.charAt(i+j);
4120 if (buf[j] != c &&
4121 buf[j] != ASCII.toLower(c))
4122 return false;
4123 }
4124 return next.match(matcher, i+len, seq);
4125 }
4126 }
4127
4128 /**
4129 * Node class for a unicode_case_insensitive/BMP-only sequence of
4130 * literal characters. Uses unicode case folding.
4131 */
4132 static final class SliceU extends SliceNode {
4133 SliceU(int[] buf) {
4134 super(buf);
4135 }
4136 boolean match(Matcher matcher, int i, CharSequence seq) {
4137 int[] buf = buffer;
4138 int len = buf.length;
4139 for (int j=0; j<len; j++) {
4140 if ((i+j) >= matcher.to) {
4141 matcher.hitEnd = true;
4142 return false;
4143 }
4144 int c = seq.charAt(i+j);
4145 if (buf[j] != c &&
4146 buf[j] != Character.toLowerCase(Character.toUpperCase(c)))
4147 return false;
4148 }
4149 return next.match(matcher, i+len, seq);
4150 }
4151 }
4152
4153 /**
4154 * Node class for a case sensitive sequence of literal characters
4155 * including supplementary characters.
4156 */
4157 static final class SliceS extends Slice {
4158 SliceS(int[] buf) {
4159 super(buf);
4160 }
4161 boolean match(Matcher matcher, int i, CharSequence seq) {
4162 int[] buf = buffer;
4163 int x = i;
4164 for (int j = 0; j < buf.length; j++) {
4165 if (x >= matcher.to) {
4166 matcher.hitEnd = true;
4167 return false;
4168 }
4169 int c = Character.codePointAt(seq, x);
4170 if (buf[j] != c)
4171 return false;
4172 x += Character.charCount(c);
4173 if (x > matcher.to) {
4174 matcher.hitEnd = true;
4175 return false;
4176 }
4177 }
4178 return next.match(matcher, x, seq);
4179 }
4180 }
4181
4182 /**
4183 * Node class for a case insensitive sequence of literal characters
4184 * including supplementary characters.
4185 */
4186 static class SliceIS extends SliceNode {
4187 SliceIS(int[] buf) {
4188 super(buf);
4189 }
4190 int toLower(int c) {
4191 return ASCII.toLower(c);
4192 }
4193 boolean match(Matcher matcher, int i, CharSequence seq) {
4194 int[] buf = buffer;
4195 int x = i;
4196 for (int j = 0; j < buf.length; j++) {
4197 if (x >= matcher.to) {
4198 matcher.hitEnd = true;
4199 return false;
4200 }
4201 int c = Character.codePointAt(seq, x);
4202 if (buf[j] != c && buf[j] != toLower(c))
4203 return false;
4204 x += Character.charCount(c);
4205 if (x > matcher.to) {
4206 matcher.hitEnd = true;
4207 return false;
4208 }
4209 }
4210 return next.match(matcher, x, seq);
4211 }
4212 }
4213
4214 /**
4215 * Node class for a case insensitive sequence of literal characters.
4216 * Uses unicode case folding.
4217 */
4218 static final class SliceUS extends SliceIS {
4219 SliceUS(int[] buf) {
4220 super(buf);
4221 }
4222 int toLower(int c) {
4223 return Character.toLowerCase(Character.toUpperCase(c));
4224 }
4225 }
4226
4227 /**
4228 * The 0 or 1 quantifier. This one class implements all three types.
4229 */
4230 static final class Ques extends Node {
4231 Node atom;
4232 Qtype type;
4233 Ques(Node node, Qtype type) {
4234 this.atom = node;
4235 this.type = type;
4236 }
4237 boolean match(Matcher matcher, int i, CharSequence seq) {
4238 switch (type) {
4239 case GREEDY:
4240 return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq))
4241 || next.match(matcher, i, seq);
4242 case LAZY:
4243 return next.match(matcher, i, seq)
4244 || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq));
4245 case POSSESSIVE:
4246 if (atom.match(matcher, i, seq)) i = matcher.last;
4247 return next.match(matcher, i, seq);
4248 default:
4249 return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq);
4250 }
4251 }
4252 boolean study(TreeInfo info) {
4253 if (type != Qtype.INDEPENDENT) {
4254 int minL = info.minLength;
4255 atom.study(info);
4256 info.minLength = minL;
4257 info.deterministic = false;
4258 return next.study(info);
4259 } else {
4260 atom.study(info);
4261 return next.study(info);
4262 }
4263 }
4264 }
4265
4266 /**
4267 * Handles the greedy style repetition with the minimum either be
4268 * 0 or 1 and the maximum be MAX_REPS, for * and + quantifier.
4269 */
4270 static class CharPropertyGreedy extends Node {
4271 final CharPredicate predicate;
4272 final int cmin;
4273
4274 CharPropertyGreedy(CharProperty cp, int cmin) {
4275 this.predicate = cp.predicate;
4276 this.cmin = cmin;
4277 }
4278 boolean match(Matcher matcher, int i, CharSequence seq) {
4279 int n = 0;
4280 int to = matcher.to;
4281 // greedy, all the way down
4282 while (i < to) {
4283 int ch = Character.codePointAt(seq, i);
4284 if (!predicate.is(ch))
4285 break;
4286 i += Character.charCount(ch);
4287 n++;
4288 }
4289 if (i >= to) {
4290 matcher.hitEnd = true;
4291 }
4292 while (n >= cmin) {
4293 if (next.match(matcher, i, seq))
4294 return true;
4295 if (n == cmin)
4296 return false;
4297 // backing off if match fails
4298 int ch = Character.codePointBefore(seq, i);
4299 i -= Character.charCount(ch);
4300 n--;
4301 }
4302 return false;
4303 }
4304
4305 boolean study(TreeInfo info) {
4306 info.minLength += cmin;
4307 if (info.maxValid) {
4308 info.maxLength += MAX_REPS;
4309 }
4310 info.deterministic = false;
4311 return next.study(info);
4312 }
4313 }
4314
4315 static final class BmpCharPropertyGreedy extends CharPropertyGreedy {
4316
4317 BmpCharPropertyGreedy(BmpCharProperty bcp, int cmin) {
4318 super(bcp, cmin);
4319 }
4320
4321 boolean match(Matcher matcher, int i, CharSequence seq) {
4322 int n = 0;
4323 int to = matcher.to;
4324 while (i < to && predicate.is(seq.charAt(i))) {
4325 i++; n++;
4326 }
4327 if (i >= to) {
4328 matcher.hitEnd = true;
4329 }
4330 while (n >= cmin) {
4331 if (next.match(matcher, i, seq))
4332 return true;
4333 i--; n--; // backing off if match fails
4334 }
4335 return false;
4336 }
4337 }
4338
4339 /**
4340 * Handles the curly-brace style repetition with a specified minimum and
4341 * maximum occurrences. The * quantifier is handled as a special case.
4342 * This class handles the three types.
4343 */
4344 static final class Curly extends Node {
4345 Node atom;
4346 Qtype type;
4347 int cmin;
4348 int cmax;
4349
4350 Curly(Node node, int cmin, int cmax, Qtype type) {
4351 this.atom = node;
4352 this.type = type;
4353 this.cmin = cmin;
4354 this.cmax = cmax;
4355 }
4356 boolean match(Matcher matcher, int i, CharSequence seq) {
4357 int j;
4358 for (j = 0; j < cmin; j++) {
4359 if (atom.match(matcher, i, seq)) {
4360 i = matcher.last;
4361 continue;
4362 }
4363 return false;
4364 }
4365 if (type == Qtype.GREEDY)
4366 return match0(matcher, i, j, seq);
4367 else if (type == Qtype.LAZY)
4368 return match1(matcher, i, j, seq);
4369 else
4370 return match2(matcher, i, j, seq);
4371 }
4372 // Greedy match.
4373 // i is the index to start matching at
4374 // j is the number of atoms that have matched
4375 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4376 if (j >= cmax) {
4377 // We have matched the maximum... continue with the rest of
4378 // the regular expression
4379 return next.match(matcher, i, seq);
4380 }
4381 int backLimit = j;
4382 while (atom.match(matcher, i, seq)) {
4383 // k is the length of this match
4384 int k = matcher.last - i;
4385 if (k == 0) // Zero length match
4386 break;
4387 // Move up index and number matched
4388 i = matcher.last;
4389 j++;
4390 // We are greedy so match as many as we can
4391 while (j < cmax) {
4392 if (!atom.match(matcher, i, seq))
4393 break;
4394 if (i + k != matcher.last) {
4395 if (match0(matcher, matcher.last, j+1, seq))
4396 return true;
4397 break;
4398 }
4399 i += k;
4400 j++;
4401 }
4402 // Handle backing off if match fails
4403 while (j >= backLimit) {
4404 if (next.match(matcher, i, seq))
4405 return true;
4406 i -= k;
4407 j--;
4408 }
4409 return false;
4410 }
4411 return next.match(matcher, i, seq);
4412 }
4413 // Reluctant match. At this point, the minimum has been satisfied.
4414 // i is the index to start matching at
4415 // j is the number of atoms that have matched
4416 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4417 for (;;) {
4418 // Try finishing match without consuming any more
4419 if (next.match(matcher, i, seq))
4420 return true;
4421 // At the maximum, no match found
4422 if (j >= cmax)
4423 return false;
4424 // Okay, must try one more atom
4425 if (!atom.match(matcher, i, seq))
4426 return false;
4427 // If we haven‘t moved forward then must break out
4428 if (i == matcher.last)
4429 return false;
4430 // Move up index and number matched
4431 i = matcher.last;
4432 j++;
4433 }
4434 }
4435 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4436 for (; j < cmax; j++) {
4437 if (!atom.match(matcher, i, seq))
4438 break;
4439 if (i == matcher.last)
4440 break;
4441 i = matcher.last;
4442 }
4443 return next.match(matcher, i, seq);
4444 }
4445 boolean study(TreeInfo info) {
4446 // Save original info
4447 int minL = info.minLength;
4448 int maxL = info.maxLength;
4449 boolean maxV = info.maxValid;
4450 boolean detm = info.deterministic;
4451 info.reset();
4452
4453 atom.study(info);
4454
4455 int temp = info.minLength * cmin + minL;
4456 if (temp < minL) {
4457 temp = 0xFFFFFFF; // arbitrary large number
4458 }
4459 info.minLength = temp;
4460
4461 if (maxV & info.maxValid) {
4462 temp = info.maxLength * cmax + maxL;
4463 info.maxLength = temp;
4464 if (temp < maxL) {
4465 info.maxValid = false;
4466 }
4467 } else {
4468 info.maxValid = false;
4469 }
4470
4471 if (info.deterministic && cmin == cmax)
4472 info.deterministic = detm;
4473 else
4474 info.deterministic = false;
4475 return next.study(info);
4476 }
4477 }
4478
4479 /**
4480 * Handles the curly-brace style repetition with a specified minimum and
4481 * maximum occurrences in deterministic cases. This is an iterative
4482 * optimization over the Prolog and Loop system which would handle this
4483 * in a recursive way. The * quantifier is handled as a special case.
4484 * If capture is true then this class saves group settings and ensures
4485 * that groups are unset when backing off of a group match.
4486 */
4487 static final class GroupCurly extends Node {
4488 Node atom;
4489 Qtype type;
4490 int cmin;
4491 int cmax;
4492 int localIndex;
4493 int groupIndex;
4494 boolean capture;
4495
4496 GroupCurly(Node node, int cmin, int cmax, Qtype type, int local,
4497 int group, boolean capture) {
4498 this.atom = node;
4499 this.type = type;
4500 this.cmin = cmin;
4501 this.cmax = cmax;
4502 this.localIndex = local;
4503 this.groupIndex = group;
4504 this.capture = capture;
4505 }
4506 boolean match(Matcher matcher, int i, CharSequence seq) {
4507 int[] groups = matcher.groups;
4508 int[] locals = matcher.locals;
4509 int save0 = locals[localIndex];
4510 int save1 = 0;
4511 int save2 = 0;
4512
4513 if (capture) {
4514 save1 = groups[groupIndex];
4515 save2 = groups[groupIndex+1];
4516 }
4517
4518 // Notify GroupTail there is no need to setup group info
4519 // because it will be set here
4520 locals[localIndex] = -1;
4521
4522 boolean ret = true;
4523 for (int j = 0; j < cmin; j++) {
4524 if (atom.match(matcher, i, seq)) {
4525 if (capture) {
4526 groups[groupIndex] = i;
4527 groups[groupIndex+1] = matcher.last;
4528 }
4529 i = matcher.last;
4530 } else {
4531 ret = false;
4532 break;
4533 }
4534 }
4535 if (ret) {
4536 if (type == Qtype.GREEDY) {
4537 ret = match0(matcher, i, cmin, seq);
4538 } else if (type == Qtype.LAZY) {
4539 ret = match1(matcher, i, cmin, seq);
4540 } else {
4541 ret = match2(matcher, i, cmin, seq);
4542 }
4543 }
4544 if (!ret) {
4545 locals[localIndex] = save0;
4546 if (capture) {
4547 groups[groupIndex] = save1;
4548 groups[groupIndex+1] = save2;
4549 }
4550 }
4551 return ret;
4552 }
4553 // Aggressive group match
4554 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
4555 // don‘t back off passing the starting "j"
4556 int min = j;
4557 int[] groups = matcher.groups;
4558 int save0 = 0;
4559 int save1 = 0;
4560 if (capture) {
4561 save0 = groups[groupIndex];
4562 save1 = groups[groupIndex+1];
4563 }
4564 for (;;) {
4565 if (j >= cmax)
4566 break;
4567 if (!atom.match(matcher, i, seq))
4568 break;
4569 int k = matcher.last - i;
4570 if (k <= 0) {
4571 if (capture) {
4572 groups[groupIndex] = i;
4573 groups[groupIndex+1] = i + k;
4574 }
4575 i = i + k;
4576 break;
4577 }
4578 for (;;) {
4579 if (capture) {
4580 groups[groupIndex] = i;
4581 groups[groupIndex+1] = i + k;
4582 }
4583 i = i + k;
4584 if (++j >= cmax)
4585 break;
4586 if (!atom.match(matcher, i, seq))
4587 break;
4588 if (i + k != matcher.last) {
4589 if (match0(matcher, i, j, seq))
4590 return true;
4591 break;
4592 }
4593 }
4594 while (j > min) {
4595 if (next.match(matcher, i, seq)) {
4596 if (capture) {
4597 groups[groupIndex+1] = i;
4598 groups[groupIndex] = i - k;
4599 }
4600 return true;
4601 }
4602 // backing off
4603 i = i - k;
4604 if (capture) {
4605 groups[groupIndex+1] = i;
4606 groups[groupIndex] = i - k;
4607 }
4608 j--;
4609
4610 }
4611 break;
4612 }
4613 if (capture) {
4614 groups[groupIndex] = save0;
4615 groups[groupIndex+1] = save1;
4616 }
4617 return next.match(matcher, i, seq);
4618 }
4619 // Reluctant matching
4620 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4621 for (;;) {
4622 if (next.match(matcher, i, seq))
4623 return true;
4624 if (j >= cmax)
4625 return false;
4626 if (!atom.match(matcher, i, seq))
4627 return false;
4628 if (i == matcher.last)
4629 return false;
4630 if (capture) {
4631 matcher.groups[groupIndex] = i;
4632 matcher.groups[groupIndex+1] = matcher.last;
4633 }
4634 i = matcher.last;
4635 j++;
4636 }
4637 }
4638 // Possessive matching
4639 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4640 for (; j < cmax; j++) {
4641 if (!atom.match(matcher, i, seq)) {
4642 break;
4643 }
4644 if (capture) {
4645 matcher.groups[groupIndex] = i;
4646 matcher.groups[groupIndex+1] = matcher.last;
4647 }
4648 if (i == matcher.last) {
4649 break;
4650 }
4651 i = matcher.last;
4652 }
4653 return next.match(matcher, i, seq);
4654 }
4655 boolean study(TreeInfo info) {
4656 // Save original info
4657 int minL = info.minLength;
4658 int maxL = info.maxLength;
4659 boolean maxV = info.maxValid;
4660 boolean detm = info.deterministic;
4661 info.reset();
4662
4663 atom.study(info);
4664
4665 int temp = info.minLength * cmin + minL;
4666 if (temp < minL) {
4667 temp = 0xFFFFFFF; // Arbitrary large number
4668 }
4669 info.minLength = temp;
4670
4671 if (maxV & info.maxValid) {
4672 temp = info.maxLength * cmax + maxL;
4673 info.maxLength = temp;
4674 if (temp < maxL) {
4675 info.maxValid = false;
4676 }
4677 } else {
4678 info.maxValid = false;
4679 }
4680
4681 if (info.deterministic && cmin == cmax) {
4682 info.deterministic = detm;
4683 } else {
4684 info.deterministic = false;
4685 }
4686 return next.study(info);
4687 }
4688 }
4689
4690 /**
4691 * A Guard node at the end of each atom node in a Branch. It
4692 * serves the purpose of chaining the "match" operation to
4693 * "next" but not the "study", so we can collect the TreeInfo
4694 * of each atom node without including the TreeInfo of the
4695 * "next".
4696 */
4697 static final class BranchConn extends Node {
4698 BranchConn() {};
4699 boolean match(Matcher matcher, int i, CharSequence seq) {
4700 return next.match(matcher, i, seq);
4701 }
4702 boolean study(TreeInfo info) {
4703 return info.deterministic;
4704 }
4705 }
4706
4707 /**
4708 * Handles the branching of alternations. Note this is also used for
4709 * the ? quantifier to branch between the case where it matches once
4710 * and where it does not occur.
4711 */
4712 static final class Branch extends Node {
4713 Node[] atoms = new Node[2];
4714 int size = 2;
4715 Node conn;
4716 Branch(Node first, Node second, Node branchConn) {
4717 conn = branchConn;
4718 atoms[0] = first;
4719 atoms[1] = second;
4720 }
4721
4722 void add(Node node) {
4723 if (size >= atoms.length) {
4724 Node[] tmp = new Node[atoms.length*2];
4725 System.arraycopy(atoms, 0, tmp, 0, atoms.length);
4726 atoms = tmp;
4727 }
4728 atoms[size++] = node;
4729 }
4730
4731 boolean match(Matcher matcher, int i, CharSequence seq) {
4732 for (int n = 0; n < size; n++) {
4733 if (atoms[n] == null) {
4734 if (conn.next.match(matcher, i, seq))
4735 return true;
4736 } else if (atoms[n].match(matcher, i, seq)) {
4737 return true;
4738 }
4739 }
4740 return false;
4741 }
4742
4743 boolean study(TreeInfo info) {
4744 int minL = info.minLength;
4745 int maxL = info.maxLength;
4746 boolean maxV = info.maxValid;
4747
4748 int minL2 = Integer.MAX_VALUE; //arbitrary large enough num
4749 int maxL2 = -1;
4750 for (int n = 0; n < size; n++) {
4751 info.reset();
4752 if (atoms[n] != null)
4753 atoms[n].study(info);
4754 minL2 = Math.min(minL2, info.minLength);
4755 maxL2 = Math.max(maxL2, info.maxLength);
4756 maxV = (maxV & info.maxValid);
4757 }
4758
4759 minL += minL2;
4760 maxL += maxL2;
4761
4762 info.reset();
4763 conn.next.study(info);
4764
4765 info.minLength += minL;
4766 info.maxLength += maxL;
4767 info.maxValid &= maxV;
4768 info.deterministic = false;
4769 return false;
4770 }
4771 }
4772
4773 /**
4774 * The GroupHead saves the location where the group begins in the locals
4775 * and restores them when the match is done.
4776 *
4777 * The matchRef is used when a reference to this group is accessed later
4778 * in the expression. The locals will have a negative value in them to
4779 * indicate that we do not want to unset the group if the reference
4780 * doesn‘t match.
4781 */
4782 static final class GroupHead extends Node {
4783 int localIndex;
4784 GroupTail tail; // for debug/print only, match does not need to know
4785 GroupHead(int localCount) {
4786 localIndex = localCount;
4787 }
4788 boolean match(Matcher matcher, int i, CharSequence seq) {
4789 int save = matcher.locals[localIndex];
4790 matcher.locals[localIndex] = i;
4791 boolean ret = next.match(matcher, i, seq);
4792 matcher.locals[localIndex] = save;
4793 return ret;
4794 }
4795 boolean matchRef(Matcher matcher, int i, CharSequence seq) {
4796 int save = matcher.locals[localIndex];
4797 matcher.locals[localIndex] = ~i; // HACK
4798 boolean ret = next.match(matcher, i, seq);
4799 matcher.locals[localIndex] = save;
4800 return ret;
4801 }
4802 }
4803
4804 /**
4805 * Recursive reference to a group in the regular expression. It calls
4806 * matchRef because if the reference fails to match we would not unset
4807 * the group.
4808 */
4809 static final class GroupRef extends Node {
4810 GroupHead head;
4811 GroupRef(GroupHead head) {
4812 this.head = head;
4813 }
4814 boolean match(Matcher matcher, int i, CharSequence seq) {
4815 return head.matchRef(matcher, i, seq)
4816 && next.match(matcher, matcher.last, seq);
4817 }
4818 boolean study(TreeInfo info) {
4819 info.maxValid = false;
4820 info.deterministic = false;
4821 return next.study(info);
4822 }
4823 }
4824
4825 /**
4826 * The GroupTail handles the setting of group beginning and ending
4827 * locations when groups are successfully matched. It must also be able to
4828 * unset groups that have to be backed off of.
4829 *
4830 * The GroupTail node is also used when a previous group is referenced,
4831 * and in that case no group information needs to be set.
4832 */
4833 static final class GroupTail extends Node {
4834 int localIndex;
4835 int groupIndex;
4836 GroupTail(int localCount, int groupCount) {
4837 localIndex = localCount;
4838 groupIndex = groupCount + groupCount;
4839 }
4840 boolean match(Matcher matcher, int i, CharSequence seq) {
4841 int tmp = matcher.locals[localIndex];
4842 if (tmp >= 0) { // This is the normal group case.
4843 // Save the group so we can unset it if it
4844 // backs off of a match.
4845 int groupStart = matcher.groups[groupIndex];
4846 int groupEnd = matcher.groups[groupIndex+1];
4847
4848 matcher.groups[groupIndex] = tmp;
4849 matcher.groups[groupIndex+1] = i;
4850 if (next.match(matcher, i, seq)) {
4851 return true;
4852 }
4853 matcher.groups[groupIndex] = groupStart;
4854 matcher.groups[groupIndex+1] = groupEnd;
4855 return false;
4856 } else {
4857 // This is a group reference case. We don‘t need to save any
4858 // group info because it isn‘t really a group.
4859 matcher.last = i;
4860 return true;
4861 }
4862 }
4863 }
4864
4865 /**
4866 * This sets up a loop to handle a recursive quantifier structure.
4867 */
4868 static final class Prolog extends Node {
4869 Loop loop;
4870 Prolog(Loop loop) {
4871 this.loop = loop;
4872 }
4873 boolean match(Matcher matcher, int i, CharSequence seq) {
4874 return loop.matchInit(matcher, i, seq);
4875 }
4876 boolean study(TreeInfo info) {
4877 return loop.study(info);
4878 }
4879 }
4880
4881 /**
4882 * Handles the repetition count for a greedy Curly. The matchInit
4883 * is called from the Prolog to save the index of where the group
4884 * beginning is stored. A zero length group check occurs in the
4885 * normal match but is skipped in the matchInit.
4886 */
4887 static class Loop extends Node {
4888 Node body;
4889 int countIndex; // local count index in matcher locals
4890 int beginIndex; // group beginning index
4891 int cmin, cmax;
4892 int posIndex;
4893 Loop(int countIndex, int beginIndex) {
4894 this.countIndex = countIndex;
4895 this.beginIndex = beginIndex;
4896 this.posIndex = -1;
4897 }
4898 boolean match(Matcher matcher, int i, CharSequence seq) {
4899 // Avoid infinite loop in zero-length case.
4900 if (i > matcher.locals[beginIndex]) {
4901 int count = matcher.locals[countIndex];
4902
4903 // This block is for before we reach the minimum
4904 // iterations required for the loop to match
4905 if (count < cmin) {
4906 matcher.locals[countIndex] = count + 1;
4907 boolean b = body.match(matcher, i, seq);
4908 // If match failed we must backtrack, so
4909 // the loop count should NOT be incremented
4910 if (!b)
4911 matcher.locals[countIndex] = count;
4912 // Return success or failure since we are under
4913 // minimum
4914 return b;
4915 }
4916 // This block is for after we have the minimum
4917 // iterations required for the loop to match
4918 if (count < cmax) {
4919 // Let‘s check if we have already tried and failed
4920 // at this starting position "i" in the past.
4921 // If yes, then just return false wihtout trying
4922 // again, to stop the exponential backtracking.
4923 if (posIndex != -1 &&
4924 matcher.localsPos[posIndex].contains(i)) {
4925 return next.match(matcher, i, seq);
4926 }
4927 matcher.locals[countIndex] = count + 1;
4928 boolean b = body.match(matcher, i, seq);
4929 // If match failed we must backtrack, so
4930 // the loop count should NOT be incremented
4931 if (b)
4932 return true;
4933 matcher.locals[countIndex] = count;
4934 // save the failed position
4935 if (posIndex != -1) {
4936 matcher.localsPos[posIndex].add(i);
4937 }
4938 }
4939 }
4940 return next.match(matcher, i, seq);
4941 }
4942 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4943 int save = matcher.locals[countIndex];
4944 boolean ret = false;
4945 if (posIndex != -1 && matcher.localsPos[posIndex] == null) {
4946 matcher.localsPos[posIndex] = new IntHashSet();
4947 }
4948 if (0 < cmin) {
4949 matcher.locals[countIndex] = 1;
4950 ret = body.match(matcher, i, seq);
4951 } else if (0 < cmax) {
4952 matcher.locals[countIndex] = 1;
4953 ret = body.match(matcher, i, seq);
4954 if (ret == false)
4955 ret = next.match(matcher, i, seq);
4956 } else {
4957 ret = next.match(matcher, i, seq);
4958 }
4959 matcher.locals[countIndex] = save;
4960 return ret;
4961 }
4962 boolean study(TreeInfo info) {
4963 info.maxValid = false;
4964 info.deterministic = false;
4965 return false;
4966 }
4967 }
4968
4969 /**
4970 * Handles the repetition count for a reluctant Curly. The matchInit
4971 * is called from the Prolog to save the index of where the group
4972 * beginning is stored. A zero length group check occurs in the
4973 * normal match but is skipped in the matchInit.
4974 */
4975 static final class LazyLoop extends Loop {
4976 LazyLoop(int countIndex, int beginIndex) {
4977 super(countIndex, beginIndex);
4978 }
4979 boolean match(Matcher matcher, int i, CharSequence seq) {
4980 // Check for zero length group
4981 if (i > matcher.locals[beginIndex]) {
4982 int count = matcher.locals[countIndex];
4983 if (count < cmin) {
4984 matcher.locals[countIndex] = count + 1;
4985 boolean result = body.match(matcher, i, seq);
4986 // If match failed we must backtrack, so
4987 // the loop count should NOT be incremented
4988 if (!result)
4989 matcher.locals[countIndex] = count;
4990 return result;
4991 }
4992 if (next.match(matcher, i, seq))
4993 return true;
4994 if (count < cmax) {
4995 matcher.locals[countIndex] = count + 1;
4996 boolean result = body.match(matcher, i, seq);
4997 // If match failed we must backtrack, so
4998 // the loop count should NOT be incremented
4999 if (!result)
5000 matcher.locals[countIndex] = count;
5001 return result;
5002 }
5003 return false;
5004 }
5005 return next.match(matcher, i, seq);
5006 }
5007 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
5008 int save = matcher.locals[countIndex];
5009 boolean ret = false;
5010 if (0 < cmin) {
5011 matcher.locals[countIndex] = 1;
5012 ret = body.match(matcher, i, seq);
5013 } else if (next.match(matcher, i, seq)) {
5014 ret = true;
5015 } else if (0 < cmax) {
5016 matcher.locals[countIndex] = 1;
5017 ret = body.match(matcher, i, seq);
5018 }
5019 matcher.locals[countIndex] = save;
5020 return ret;
5021 }
5022 boolean study(TreeInfo info) {
5023 info.maxValid = false;
5024 info.deterministic = false;
5025 return false;
5026 }
5027 }
5028
5029 /**
5030 * Refers to a group in the regular expression. Attempts to match
5031 * whatever the group referred to last matched.
5032 */
5033 static class BackRef extends Node {
5034 int groupIndex;
5035 BackRef(int groupCount) {
5036 super();
5037 groupIndex = groupCount + groupCount;
5038 }
5039 boolean match(Matcher matcher, int i, CharSequence seq) {
5040 int j = matcher.groups[groupIndex];
5041 int k = matcher.groups[groupIndex+1];
5042
5043 int groupSize = k - j;
5044 // If the referenced group didn‘t match, neither can this
5045 if (j < 0)
5046 return false;
5047
5048 // If there isn‘t enough input left no match
5049 if (i + groupSize > matcher.to) {
5050 matcher.hitEnd = true;
5051 return false;
5052 }
5053 // Check each new char to make sure it matches what the group
5054 // referenced matched last time around
5055 for (int index=0; index<groupSize; index++)
5056 if (seq.charAt(i+index) != seq.charAt(j+index))
5057 return false;
5058
5059 return next.match(matcher, i+groupSize, seq);
5060 }
5061 boolean study(TreeInfo info) {
5062 info.maxValid = false;
5063 return next.study(info);
5064 }
5065 }
5066
5067 static class CIBackRef extends Node {
5068 int groupIndex;
5069 boolean doUnicodeCase;
5070 CIBackRef(int groupCount, boolean doUnicodeCase) {
5071 super();
5072 groupIndex = groupCount + groupCount;
5073 this.doUnicodeCase = doUnicodeCase;
5074 }
5075 boolean match(Matcher matcher, int i, CharSequence seq) {
5076 int j = matcher.groups[groupIndex];
5077 int k = matcher.groups[groupIndex+1];
5078
5079 int groupSize = k - j;
5080
5081 // If the referenced group didn‘t match, neither can this
5082 if (j < 0)
5083 return false;
5084
5085 // If there isn‘t enough input left no match
5086 if (i + groupSize > matcher.to) {
5087 matcher.hitEnd = true;
5088 return false;
5089 }
5090
5091 // Check each new char to make sure it matches what the group
5092 // referenced matched last time around
5093 int x = i;
5094 for (int index=0; index<groupSize; index++) {
5095 int c1 = Character.codePointAt(seq, x);
5096 int c2 = Character.codePointAt(seq, j);
5097 if (c1 != c2) {
5098 if (doUnicodeCase) {
5099 int cc1 = Character.toUpperCase(c1);
5100 int cc2 = Character.toUpperCase(c2);
5101 if (cc1 != cc2 &&
5102 Character.toLowerCase(cc1) !=
5103 Character.toLowerCase(cc2))
5104 return false;
5105 } else {
5106 if (ASCII.toLower(c1) != ASCII.toLower(c2))
5107 return false;
5108 }
5109 }
5110 x += Character.charCount(c1);
5111 j += Character.charCount(c2);
5112 }
5113
5114 return next.match(matcher, i+groupSize, seq);
5115 }
5116 boolean study(TreeInfo info) {
5117 info.maxValid = false;
5118 return next.study(info);
5119 }
5120 }
5121
5122 /**
5123 * Searches until the next instance of its atom. This is useful for
5124 * finding the atom efficiently without passing an instance of it
5125 * (greedy problem) and without a lot of wasted search time (reluctant
5126 * problem).
5127 */
5128 static final class First extends Node {
5129 Node atom;
5130 First(Node node) {
5131 this.atom = BnM.optimize(node);
5132 }
5133 boolean match(Matcher matcher, int i, CharSequence seq) {
5134 if (atom instanceof BnM) {
5135 return atom.match(matcher, i, seq)
5136 && next.match(matcher, matcher.last, seq);
5137 }
5138 for (;;) {
5139 if (i > matcher.to) {
5140 matcher.hitEnd = true;
5141 return false;
5142 }
5143 if (atom.match(matcher, i, seq)) {
5144 return next.match(matcher, matcher.last, seq);
5145 }
5146 i += countChars(seq, i, 1);
5147 matcher.first++;
5148 }
5149 }
5150 boolean study(TreeInfo info) {
5151 atom.study(info);
5152 info.maxValid = false;
5153 info.deterministic = false;
5154 return next.study(info);
5155 }
5156 }
5157
5158 static final class Conditional extends Node {
5159 Node cond, yes, not;
5160 Conditional(Node cond, Node yes, Node not) {
5161 this.cond = cond;
5162 this.yes = yes;
5163 this.not = not;
5164 }
5165 boolean match(Matcher matcher, int i, CharSequence seq) {
5166 if (cond.match(matcher, i, seq)) {
5167 return yes.match(matcher, i, seq);
5168 } else {
5169 return not.match(matcher, i, seq);
5170 }
5171 }
5172 boolean study(TreeInfo info) {
5173 int minL = info.minLength;
5174 int maxL = info.maxLength;
5175 boolean maxV = info.maxValid;
5176 info.reset();
5177 yes.study(info);
5178
5179 int minL2 = info.minLength;
5180 int maxL2 = info.maxLength;
5181 boolean maxV2 = info.maxValid;
5182 info.reset();
5183 not.study(info);
5184
5185 info.minLength = minL + Math.min(minL2, info.minLength);
5186 info.maxLength = maxL + Math.max(maxL2, info.maxLength);
5187 info.maxValid = (maxV & maxV2 & info.maxValid);
5188 info.deterministic = false;
5189 return next.study(info);
5190 }
5191 }
5192
5193 /**
5194 * Zero width positive lookahead.
5195 */
5196 static final class Pos extends Node {
5197 Node cond;
5198 Pos(Node cond) {
5199 this.cond = cond;
5200 }
5201 boolean match(Matcher matcher, int i, CharSequence seq) {
5202 int savedTo = matcher.to;
5203 boolean conditionMatched = false;
5204
5205 // Relax transparent region boundaries for lookahead
5206 if (matcher.transparentBounds)
5207 matcher.to = matcher.getTextLength();
5208 try {
5209 conditionMatched = cond.match(matcher, i, seq);
5210 } finally {
5211 // Reinstate region boundaries
5212 matcher.to = savedTo;
5213 }
5214 return conditionMatched && next.match(matcher, i, seq);
5215 }
5216 }
5217
5218 /**
5219 * Zero width negative lookahead.
5220 */
5221 static final class Neg extends Node {
5222 Node cond;
5223 Neg(Node cond) {
5224 this.cond = cond;
5225 }
5226 boolean match(Matcher matcher, int i, CharSequence seq) {
5227 int savedTo = matcher.to;
5228 boolean conditionMatched = false;
5229
5230 // Relax transparent region boundaries for lookahead
5231 if (matcher.transparentBounds)
5232 matcher.to = matcher.getTextLength();
5233 try {
5234 if (i < matcher.to) {
5235 conditionMatched = !cond.match(matcher, i, seq);
5236 } else {
5237 // If a negative lookahead succeeds then more input
5238 // could cause it to fail!
5239 matcher.requireEnd = true;
5240 conditionMatched = !cond.match(matcher, i, seq);
5241 }
5242 } finally {
5243 // Reinstate region boundaries
5244 matcher.to = savedTo;
5245 }
5246 return conditionMatched && next.match(matcher, i, seq);
5247 }
5248 }
5249
5250 /**
5251 * For use with lookbehinds; matches the position where the lookbehind
5252 * was encountered.
5253 */
5254 static Node lookbehindEnd = new Node() {
5255 boolean match(Matcher matcher, int i, CharSequence seq) {
5256 return i == matcher.lookbehindTo;
5257 }
5258 };
5259
5260 /**
5261 * Zero width positive lookbehind.
5262 */
5263 static class Behind extends Node {
5264 Node cond;
5265 int rmax, rmin;
5266 Behind(Node cond, int rmax, int rmin) {
5267 this.cond = cond;
5268 this.rmax = rmax;
5269 this.rmin = rmin;
5270 }
5271
5272 boolean match(Matcher matcher, int i, CharSequence seq) {
5273 int savedFrom = matcher.from;
5274 boolean conditionMatched = false;
5275 int startIndex = (!matcher.transparentBounds) ?
5276 matcher.from : 0;
5277 int from = Math.max(i - rmax, startIndex);
5278 // Set end boundary
5279 int savedLBT = matcher.lookbehindTo;
5280 matcher.lookbehindTo = i;
5281 // Relax transparent region boundaries for lookbehind
5282 if (matcher.transparentBounds)
5283 matcher.from = 0;
5284 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5285 conditionMatched = cond.match(matcher, j, seq);
5286 }
5287 matcher.from = savedFrom;
5288 matcher.lookbehindTo = savedLBT;
5289 return conditionMatched && next.match(matcher, i, seq);
5290 }
5291 }
5292
5293 /**
5294 * Zero width positive lookbehind, including supplementary
5295 * characters or unpaired surrogates.
5296 */
5297 static final class BehindS extends Behind {
5298 BehindS(Node cond, int rmax, int rmin) {
5299 super(cond, rmax, rmin);
5300 }
5301 boolean match(Matcher matcher, int i, CharSequence seq) {
5302 int rmaxChars = countChars(seq, i, -rmax);
5303 int rminChars = countChars(seq, i, -rmin);
5304 int savedFrom = matcher.from;
5305 int startIndex = (!matcher.transparentBounds) ?
5306 matcher.from : 0;
5307 boolean conditionMatched = false;
5308 int from = Math.max(i - rmaxChars, startIndex);
5309 // Set end boundary
5310 int savedLBT = matcher.lookbehindTo;
5311 matcher.lookbehindTo = i;
5312 // Relax transparent region boundaries for lookbehind
5313 if (matcher.transparentBounds)
5314 matcher.from = 0;
5315
5316 for (int j = i - rminChars;
5317 !conditionMatched && j >= from;
5318 j -= j>from ? countChars(seq, j, -1) : 1) {
5319 conditionMatched = cond.match(matcher, j, seq);
5320 }
5321 matcher.from = savedFrom;
5322 matcher.lookbehindTo = savedLBT;
5323 return conditionMatched && next.match(matcher, i, seq);
5324 }
5325 }
5326
5327 /**
5328 * Zero width negative lookbehind.
5329 */
5330 static class NotBehind extends Node {
5331 Node cond;
5332 int rmax, rmin;
5333 NotBehind(Node cond, int rmax, int rmin) {
5334 this.cond = cond;
5335 this.rmax = rmax;
5336 this.rmin = rmin;
5337 }
5338
5339 boolean match(Matcher matcher, int i, CharSequence seq) {
5340 int savedLBT = matcher.lookbehindTo;
5341 int savedFrom = matcher.from;
5342 boolean conditionMatched = false;
5343 int startIndex = (!matcher.transparentBounds) ?
5344 matcher.from : 0;
5345 int from = Math.max(i - rmax, startIndex);
5346 matcher.lookbehindTo = i;
5347 // Relax transparent region boundaries for lookbehind
5348 if (matcher.transparentBounds)
5349 matcher.from = 0;
5350 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
5351 conditionMatched = cond.match(matcher, j, seq);
5352 }
5353 // Reinstate region boundaries
5354 matcher.from = savedFrom;
5355 matcher.lookbehindTo = savedLBT;
5356 return !conditionMatched && next.match(matcher, i, seq);
5357 }
5358 }
5359
5360 /**
5361 * Zero width negative lookbehind, including supplementary
5362 * characters or unpaired surrogates.
5363 */
5364 static final class NotBehindS extends NotBehind {
5365 NotBehindS(Node cond, int rmax, int rmin) {
5366 super(cond, rmax, rmin);
5367 }
5368 boolean match(Matcher matcher, int i, CharSequence seq) {
5369 int rmaxChars = countChars(seq, i, -rmax);
5370 int rminChars = countChars(seq, i, -rmin);
5371 int savedFrom = matcher.from;
5372 int savedLBT = matcher.lookbehindTo;
5373 boolean conditionMatched = false;
5374 int startIndex = (!matcher.transparentBounds) ?
5375 matcher.from : 0;
5376 int from = Math.max(i - rmaxChars, startIndex);
5377 matcher.lookbehindTo = i;
5378 // Relax transparent region boundaries for lookbehind
5379 if (matcher.transparentBounds)
5380 matcher.from = 0;
5381 for (int j = i - rminChars;
5382 !conditionMatched && j >= from;
5383 j -= j>from ? countChars(seq, j, -1) : 1) {
5384 conditionMatched = cond.match(matcher, j, seq);
5385 }
5386 //Reinstate region boundaries
5387 matcher.from = savedFrom;
5388 matcher.lookbehindTo = savedLBT;
5389 return !conditionMatched && next.match(matcher, i, seq);
5390 }
5391 }
5392
5393 /**
5394 * Handles word boundaries. Includes a field to allow this one class to
5395 * deal with the different types of word boundaries we can match. The word
5396 * characters include underscores, letters, and digits. Non spacing marks
5397 * can are also part of a word if they have a base character, otherwise
5398 * they are ignored for purposes of finding word boundaries.
5399 */
5400 static final class Bound extends Node {
5401 static int LEFT = 0x1;
5402 static int RIGHT= 0x2;
5403 static int BOTH = 0x3;
5404 static int NONE = 0x4;
5405 int type;
5406 boolean useUWORD;
5407 Bound(int n, boolean useUWORD) {
5408 type = n;
5409 this.useUWORD = useUWORD;
5410 }
5411
5412 boolean isWord(int ch) {
5413 return useUWORD ? CharPredicates.WORD().is(ch)
5414 : (ch == ‘_‘ || Character.isLetterOrDigit(ch));
5415 }
5416
5417 int check(Matcher matcher, int i, CharSequence seq) {
5418 int ch;
5419 boolean left = false;
5420 int startIndex = matcher.from;
5421 int endIndex = matcher.to;
5422 if (matcher.transparentBounds) {
5423 startIndex = 0;
5424 endIndex = matcher.getTextLength();
5425 }
5426 if (i > startIndex) {
5427 ch = Character.codePointBefore(seq, i);
5428 left = (isWord(ch) ||
5429 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5430 && hasBaseCharacter(matcher, i-1, seq)));
5431 }
5432 boolean right = false;
5433 if (i < endIndex) {
5434 ch = Character.codePointAt(seq, i);
5435 right = (isWord(ch) ||
5436 ((Character.getType(ch) == Character.NON_SPACING_MARK)
5437 && hasBaseCharacter(matcher, i, seq)));
5438 } else {
5439 // Tried to access char past the end
5440 matcher.hitEnd = true;
5441 // The addition of another char could wreck a boundary
5442 matcher.requireEnd = true;
5443 }
5444 return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE);
5445 }
5446 boolean match(Matcher matcher, int i, CharSequence seq) {
5447 return (check(matcher, i, seq) & type) > 0
5448 && next.match(matcher, i, seq);
5449 }
5450 }
5451
5452 /**
5453 * Non spacing marks only count as word characters in bounds calculations
5454 * if they have a base character.
5455 */
5456 private static boolean hasBaseCharacter(Matcher matcher, int i,
5457 CharSequence seq)
5458 {
5459 int start = (!matcher.transparentBounds) ?
5460 matcher.from : 0;
5461 for (int x=i; x >= start; x--) {
5462 int ch = Character.codePointAt(seq, x);
5463 if (Character.isLetterOrDigit(ch))
5464 return true;
5465 if (Character.getType(ch) == Character.NON_SPACING_MARK)
5466 continue;
5467 return false;
5468 }
5469 return false;
5470 }
5471
5472 /**
5473 * Attempts to match a slice in the input using the Boyer-Moore string
5474 * matching algorithm. The algorithm is based on the idea that the
5475 * pattern can be shifted farther ahead in the search text if it is
5476 * matched right to left.
5477 * <p>
5478 * The pattern is compared to the input one character at a time, from
5479 * the rightmost character in the pattern to the left. If the characters
5480 * all match the pattern has been found. If a character does not match,
5481 * the pattern is shifted right a distance that is the maximum of two
5482 * functions, the bad character shift and the good suffix shift. This
5483 * shift moves the attempted match position through the input more
5484 * quickly than a naive one position at a time check.
5485 * <p>
5486 * The bad character shift is based on the character from the text that
5487 * did not match. If the character does not appear in the pattern, the
5488 * pattern can be shifted completely beyond the bad character. If the
5489 * character does occur in the pattern, the pattern can be shifted to
5490 * line the pattern up with the next occurrence of that character.
5491 * <p>
5492 * The good suffix shift is based on the idea that some subset on the right
5493 * side of the pattern has matched. When a bad character is found, the
5494 * pattern can be shifted right by the pattern length if the subset does
5495 * not occur again in pattern, or by the amount of distance to the
5496 * next occurrence of the subset in the pattern.
5497 *
5498 * Boyer-Moore search methods adapted from code by Amy Yu.
5499 */
5500 static class BnM extends Node {
5501 int[] buffer;
5502 int[] lastOcc;
5503 int[] optoSft;
5504
5505 /**
5506 * Pre calculates arrays needed to generate the bad character
5507 * shift and the good suffix shift. Only the last seven bits
5508 * are used to see if chars match; This keeps the tables small
5509 * and covers the heavily used ASCII range, but occasionally
5510 * results in an aliased match for the bad character shift.
5511 */
5512 static Node optimize(Node node) {
5513 if (!(node instanceof Slice)) {
5514 return node;
5515 }
5516
5517 int[] src = ((Slice) node).buffer;
5518 int patternLength = src.length;
5519 // The BM algorithm requires a bit of overhead;
5520 // If the pattern is short don‘t use it, since
5521 // a shift larger than the pattern length cannot
5522 // be used anyway.
5523 if (patternLength < 4) {
5524 return node;
5525 }
5526 int i, j, k;
5527 int[] lastOcc = new int[128];
5528 int[] optoSft = new int[patternLength];
5529 // Precalculate part of the bad character shift
5530 // It is a table for where in the pattern each
5531 // lower 7-bit value occurs
5532 for (i = 0; i < patternLength; i++) {
5533 lastOcc[src[i]&0x7F] = i + 1;
5534 }
5535 // Precalculate the good suffix shift
5536 // i is the shift amount being considered
5537 NEXT: for (i = patternLength; i > 0; i--) {
5538 // j is the beginning index of suffix being considered
5539 for (j = patternLength - 1; j >= i; j--) {
5540 // Testing for good suffix
5541 if (src[j] == src[j-i]) {
5542 // src[j..len] is a good suffix
5543 optoSft[j-1] = i;
5544 } else {
5545 // No match. The array has already been
5546 // filled up with correct values before.
5547 continue NEXT;
5548 }
5549 }
5550 // This fills up the remaining of optoSft
5551 // any suffix can not have larger shift amount
5552 // then its sub-suffix. Why???
5553 while (j > 0) {
5554 optoSft[--j] = i;
5555 }
5556 }
5557 // Set the guard value because of unicode compression
5558 optoSft[patternLength-1] = 1;
5559 if (node instanceof SliceS)
5560 return new BnMS(src, lastOcc, optoSft, node.next);
5561 return new BnM(src, lastOcc, optoSft, node.next);
5562 }
5563 BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5564 this.buffer = src;
5565 this.lastOcc = lastOcc;
5566 this.optoSft = optoSft;
5567 this.next = next;
5568 }
5569 boolean match(Matcher matcher, int i, CharSequence seq) {
5570 int[] src = buffer;
5571 int patternLength = src.length;
5572 int last = matcher.to - patternLength;
5573
5574 // Loop over all possible match positions in text
5575 NEXT: while (i <= last) {
5576 // Loop over pattern from right to left
5577 for (int j = patternLength - 1; j >= 0; j--) {
5578 int ch = seq.charAt(i+j);
5579 if (ch != src[j]) {
5580 // Shift search to the right by the maximum of the
5581 // bad character shift and the good suffix shift
5582 i += Math.max(j + 1 - lastOcc[ch&0x7F], optoSft[j]);
5583 continue NEXT;
5584 }
5585 }
5586 // Entire pattern matched starting at i
5587 matcher.first = i;
5588 boolean ret = next.match(matcher, i + patternLength, seq);
5589 if (ret) {
5590 matcher.first = i;
5591 matcher.groups[0] = matcher.first;
5592 matcher.groups[1] = matcher.last;
5593 return true;
5594 }
5595 i++;
5596 }
5597 // BnM is only used as the leading node in the unanchored case,
5598 // and it replaced its Start() which always searches to the end
5599 // if it doesn‘t find what it‘s looking for, so hitEnd is true.
5600 matcher.hitEnd = true;
5601 return false;
5602 }
5603 boolean study(TreeInfo info) {
5604 info.minLength += buffer.length;
5605 info.maxValid = false;
5606 return next.study(info);
5607 }
5608 }
5609
5610 /**
5611 * Supplementary support version of BnM(). Unpaired surrogates are
5612 * also handled by this class.
5613 */
5614 static final class BnMS extends BnM {
5615 int lengthInChars;
5616
5617 BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5618 super(src, lastOcc, optoSft, next);
5619 for (int cp : buffer) {
5620 lengthInChars += Character.charCount(cp);
5621 }
5622 }
5623 boolean match(Matcher matcher, int i, CharSequence seq) {
5624 int[] src = buffer;
5625 int patternLength = src.length;
5626 int last = matcher.to - lengthInChars;
5627
5628 // Loop over all possible match positions in text
5629 NEXT: while (i <= last) {
5630 // Loop over pattern from right to left
5631 int ch;
5632 for (int j = countChars(seq, i, patternLength), x = patternLength - 1;
5633 j > 0; j -= Character.charCount(ch), x--) {
5634 ch = Character.codePointBefore(seq, i+j);
5635 if (ch != src[x]) {
5636 // Shift search to the right by the maximum of the
5637 // bad character shift and the good suffix shift
5638 int n = Math.max(x + 1 - lastOcc[ch&0x7F], optoSft[x]);
5639 i += countChars(seq, i, n);
5640 continue NEXT;
5641 }
5642 }
5643 // Entire pattern matched starting at i
5644 matcher.first = i;
5645 boolean ret = next.match(matcher, i + lengthInChars, seq);
5646 if (ret) {
5647 matcher.first = i;
5648 matcher.groups[0] = matcher.first;
5649 matcher.groups[1] = matcher.last;
5650 return true;
5651 }
5652 i += countChars(seq, i, 1);
5653 }
5654 matcher.hitEnd = true;
5655 return false;
5656 }
5657 }
5658
5659 @FunctionalInterface
5660 static interface CharPredicate {
5661 boolean is(int ch);
5662
5663 default CharPredicate and(CharPredicate p) {
5664 return ch -> is(ch) && p.is(ch);
5665 }
5666 default CharPredicate union(CharPredicate p) {
5667 return ch -> is(ch) || p.is(ch);
5668 }
5669 default CharPredicate union(CharPredicate p1,
5670 CharPredicate p2 ) {
5671 return ch -> is(ch) || p1.is(ch) || p2.is(ch);
5672 }
5673 default CharPredicate negate() {
5674 return ch -> !is(ch);
5675 }
5676 }
5677
5678 static interface BmpCharPredicate extends CharPredicate {
5679
5680 default CharPredicate and(CharPredicate p) {
5681 if(p instanceof BmpCharPredicate)
5682 return (BmpCharPredicate)(ch -> is(ch) && p.is(ch));
5683 return ch -> is(ch) && p.is(ch);
5684 }
5685 default CharPredicate union(CharPredicate p) {
5686 if (p instanceof BmpCharPredicate)
5687 return (BmpCharPredicate)(ch -> is(ch) || p.is(ch));
5688 return ch -> is(ch) || p.is(ch);
5689 }
5690 static CharPredicate union(CharPredicate... predicates) {
5691 CharPredicate cp = ch -> {
5692 for (CharPredicate p : predicates) {
5693 if (!p.is(ch))
5694 return false;
5695 }
5696 return true;
5697 };
5698 for (CharPredicate p : predicates) {
5699 if (! (p instanceof BmpCharPredicate))
5700 return cp;
5701 }
5702 return (BmpCharPredicate)cp;
5703 }
5704 }
5705
5706 /**
5707 * matches a Perl vertical whitespace
5708 */
5709 static BmpCharPredicate VertWS() {
5710 return cp -> (cp >= 0x0A && cp <= 0x0D) ||
5711 cp == 0x85 || cp == 0x2028 || cp == 0x2029;
5712 }
5713
5714 /**
5715 * matches a Perl horizontal whitespace
5716 */
5717 static BmpCharPredicate HorizWS() {
5718 return cp ->
5719 cp == 0x09 || cp == 0x20 || cp == 0xa0 || cp == 0x1680 ||
5720 cp == 0x180e || cp >= 0x2000 && cp <= 0x200a || cp == 0x202f ||
5721 cp == 0x205f || cp == 0x3000;
5722 }
5723
5724 /**
5725 * for the Unicode category ALL and the dot metacharacter when
5726 * in dotall mode.
5727 */
5728 static CharPredicate ALL() {
5729 return ch -> true;
5730 }
5731
5732 /**
5733 * for the dot metacharacter when dotall is not enabled.
5734 */
5735 static CharPredicate DOT() {
5736 return ch ->
5737 (ch != ‘\n‘ && ch != ‘\r‘
5738 && (ch|1) != ‘\u2029‘
5739 && ch != ‘\u0085‘);
5740 }
5741
5742 /**
5743 * the dot metacharacter when dotall is not enabled but UNIX_LINES is enabled.
5744 */
5745 static CharPredicate UNIXDOT() {
5746 return ch -> ch != ‘\n‘;
5747 }
5748
5749 /**
5750 * Indicate that matches a Supplementary Unicode character
5751 */
5752 static CharPredicate SingleS(int c) {
5753 return ch -> ch == c;
5754 }
5755
5756 /**
5757 * A bmp/optimized predicate of single
5758 */
5759 static BmpCharPredicate Single(int c) {
5760 return ch -> ch == c;
5761 }
5762
5763 /**
5764 * Case insensitive matches a given BMP character
5765 */
5766 static BmpCharPredicate SingleI(int lower, int upper) {
5767 return ch -> ch == lower || ch == upper;
5768 }
5769
5770 /**
5771 * Unicode case insensitive matches a given Unicode character
5772 */
5773 static CharPredicate SingleU(int lower) {
5774 return ch -> lower == ch ||
5775 lower == Character.toLowerCase(Character.toUpperCase(ch));
5776 }
5777
5778 private static boolean inRange(int lower, int ch, int upper) {
5779 return lower <= ch && ch <= upper;
5780 }
5781
5782 /**
5783 * Charactrs within a explicit value range
5784 */
5785 static CharPredicate Range(int lower, int upper) {
5786 if (upper < Character.MIN_HIGH_SURROGATE ||
5787 lower > Character.MAX_HIGH_SURROGATE &&
5788 upper < Character.MIN_SUPPLEMENTARY_CODE_POINT)
5789 return (BmpCharPredicate)(ch -> inRange(lower, ch, upper));
5790 return ch -> inRange(lower, ch, upper);
5791 }
5792
5793 /**
5794 * Charactrs within a explicit value range in a case insensitive manner.
5795 */
5796 static CharPredicate CIRange(int lower, int upper) {
5797 return ch -> inRange(lower, ch, upper) ||
5798 ASCII.isAscii(ch) &&
5799 (inRange(lower, ASCII.toUpper(ch), upper) ||
5800 inRange(lower, ASCII.toLower(ch), upper));
5801 }
5802
5803 static CharPredicate CIRangeU(int lower, int upper) {
5804 return ch -> {
5805 if (inRange(lower, ch, upper))
5806 return true;
5807 int up = Character.toUpperCase(ch);
5808 return inRange(lower, up, upper) ||
5809 inRange(lower, Character.toLowerCase(up), upper);
5810 };
5811 }
5812
5813 /**
5814 * This must be the very first initializer.
5815 */
5816 static final Node accept = new Node();
5817
5818 static final Node lastAccept = new LastNode();
5819
5820 /**
5821 * Creates a predicate that tests if this pattern is found in a given input
5822 * string.
5823 *
5824 * @apiNote
5825 * This method creates a predicate that behaves as if it creates a matcher
5826 * from the input sequence and then calls {@code find}, for example a
5827 * predicate of the form:
5828 * <pre>{@code
5829 * s -> matcher(s).find();
5830 * }</pre>
5831 *
5832 * @return The predicate which can be used for finding a match on a
5833 * subsequence of a string
5834 * @since 1.8
5835 * @see Matcher#find
5836 */
5837 public Predicate<String> asPredicate() {
5838 return s -> matcher(s).find();
5839 }
5840
5841 /**
5842 * Creates a predicate that tests if this pattern matches a given input string.
5843 *
5844 * @apiNote
5845 * This method creates a predicate that behaves as if it creates a matcher
5846 * from the input sequence and then calls {@code matches}, for example a
5847 * predicate of the form:
5848 * <pre>{@code
5849 * s -> matcher(s).matches();
5850 * }</pre>
5851 *
5852 * @return The predicate which can be used for matching an input string
5853 * against this pattern.
5854 * @since 11
5855 * @see Matcher#matches
5856 */
5857 public Predicate<String> asMatchPredicate() {
5858 return s -> matcher(s).matches();
5859 }
5860
5861 /**
5862 * Creates a stream from the given input sequence around matches of this
5863 * pattern.
5864 *
5865 * <p> The stream returned by this method contains each substring of the
5866 * input sequence that is terminated by another subsequence that matches
5867 * this pattern or is terminated by the end of the input sequence. The
5868 * substrings in the stream are in the order in which they occur in the
5869 * input. Trailing empty strings will be discarded and not encountered in
5870 * the stream.
5871 *
5872 * <p> If this pattern does not match any subsequence of the input then
5873 * the resulting stream has just one element, namely the input sequence in
5874 * string form.
5875 *
5876 * <p> When there is a positive-width match at the beginning of the input
5877 * sequence then an empty leading substring is included at the beginning
5878 * of the stream. A zero-width match at the beginning however never produces
5879 * such empty leading substring.
5880 *
5881 * <p> If the input sequence is mutable, it must remain constant during the
5882 * execution of the terminal stream operation. Otherwise, the result of the
5883 * terminal stream operation is undefined.
5884 *
5885 * @param input
5886 * The character sequence to be split
5887 *
5888 * @return The stream of strings computed by splitting the input
5889 * around matches of this pattern
5890 * @see #split(CharSequence)
5891 * @since 1.8
5892 */
5893 public Stream<String> splitAsStream(final CharSequence input) {
5894 class MatcherIterator implements Iterator<String> {
5895 private Matcher matcher;
5896 // The start position of the next sub-sequence of input
5897 // when current == input.length there are no more elements
5898 private int current;
5899 // null if the next element, if any, needs to obtained
5900 private String nextElement;
5901 // > 0 if there are N next empty elements
5902 private int emptyElementCount;
5903
5904 public String next() {
5905 if (!hasNext())
5906 throw new NoSuchElementException();
5907
5908 if (emptyElementCount == 0) {
5909 String n = nextElement;
5910 nextElement = null;
5911 return n;
5912 } else {
5913 emptyElementCount--;
5914 return "";
5915 }
5916 }
5917
5918 public boolean hasNext() {
5919 if (matcher == null) {
5920 matcher = matcher(input);
5921 // If the input is an empty string then the result can only be a
5922 // stream of the input. Induce that by setting the empty
5923 // element count to 1
5924 emptyElementCount = input.length() == 0 ? 1 : 0;
5925 }
5926 if (nextElement != null || emptyElementCount > 0)
5927 return true;
5928
5929 if (current == input.length())
5930 return false;
5931
5932 // Consume the next matching element
5933 // Count sequence of matching empty elements
5934 while (matcher.find()) {
5935 nextElement = input.subSequence(current, matcher.start()).toString();
5936 current = matcher.end();
5937 if (!nextElement.isEmpty()) {
5938 return true;
5939 } else if (current > 0) { // no empty leading substring for zero-width
5940 // match at the beginning of the input
5941 emptyElementCount++;
5942 }
5943 }
5944
5945 // Consume last matching element
5946 nextElement = input.subSequence(current, input.length()).toString();
5947 current = input.length();
5948 if (!nextElement.isEmpty()) {
5949 return true;
5950 } else {
5951 // Ignore a terminal sequence of matching empty elements
5952 emptyElementCount = 0;
5953 nextElement = null;
5954 return false;
5955 }
5956 }
5957 }
5958 return StreamSupport.stream(Spliterators.spliteratorUnknownSize(
5959 new MatcherIterator(), Spliterator.ORDERED | Spliterator.NONNULL), false);
5960 }
5961 }
原文地址：https://www.cnblogs.com/zhangyishu/p/11263309.html
时间： 2024-11-07 06:04:39