1 /*
2 * Copyright 1999-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.util.regex;
27
28 import java.security.AccessController;
29 import java.security.PrivilegedAction;
30 import java.text.CharacterIterator;
31 import java.text.Normalizer;
32 import java.util.ArrayList;
33 import java.util.HashMap;
34 import java.util.Arrays;
35
36
37 /**
38 * A compiled representation of a regular expression.
39 *
40 * <p> A regular expression, specified as a string, must first be compiled into
41 * an instance of this class. The resulting pattern can then be used to create
42 * a {@link Matcher} object that can match arbitrary {@link
43 * java.lang.CharSequence </code>character sequences<code>} against the regular
44 * expression. All of the state involved in performing a match resides in the
45 * matcher, so many matchers can share the same pattern.
46 *
47 * <p> A typical invocation sequence is thus
48 *
49 * <blockquote><pre>
50 * Pattern p = Pattern.{@link #compile compile}("a*b");
51 * Matcher m = p.{@link #matcher matcher}("aaaaab");
52 * boolean b = m.{@link Matcher#matches matches}();</pre></blockquote>
53 *
54 * <p> A {@link #matches matches} method is defined by this class as a
55 * convenience for when a regular expression is used just once. This method
56 * compiles an expression and matches an input sequence against it in a single
57 * invocation. The statement
58 *
59 * <blockquote><pre>
60 * boolean b = Pattern.matches("a*b", "aaaaab");</pre></blockquote>
61 *
62 * is equivalent to the three statements above, though for repeated matches it
63 * is less efficient since it does not allow the compiled pattern to be reused.
64 *
65 * <p> Instances of this class are immutable and are safe for use by multiple
66 * concurrent threads. Instances of the {@link Matcher} class are not safe for
67 * such use.
68 *
69 *
70 * <a name="sum">
71 * <h4> Summary of regular-expression constructs </h4>
72 *
73 * <table border="0" cellpadding="1" cellspacing="0"
74 * summary="Regular expression constructs, and what they match">
75 *
76 * <tr align="left">
77 * <th bgcolor="#CCCCFF" align="left" id="construct">Construct</th>
78 * <th bgcolor="#CCCCFF" align="left" id="matches">Matches</th>
79 * </tr>
80 *
81 * <tr><th> </th></tr>
82 * <tr align="left"><th colspan="2" id="characters">Characters</th></tr>
83 *
84 * <tr><td valign="top" headers="construct characters"><i>x</i></td>
85 * <td headers="matches">The character <i>x</i></td></tr>
86 * <tr><td valign="top" headers="construct characters"><tt>\\</tt></td>
87 * <td headers="matches">The backslash character</td></tr>
88 * <tr><td valign="top" headers="construct characters"><tt>\0</tt><i>n</i></td>
89 * <td headers="matches">The character with octal value <tt>0</tt><i>n</i>
90 * (0 <tt><=</tt> <i>n</i> <tt><=</tt> 7)</td></tr>
91 * <tr><td valign="top" headers="construct characters"><tt>\0</tt><i>nn</i></td>
92 * <td headers="matches">The character with octal value <tt>0</tt><i>nn</i>
93 * (0 <tt><=</tt> <i>n</i> <tt><=</tt> 7)</td></tr>
94 * <tr><td valign="top" headers="construct characters"><tt>\0</tt><i>mnn</i></td>
95 * <td headers="matches">The character with octal value <tt>0</tt><i>mnn</i>
96 * (0 <tt><=</tt> <i>m</i> <tt><=</tt> 3,
97 * 0 <tt><=</tt> <i>n</i> <tt><=</tt> 7)</td></tr>
98 * <tr><td valign="top" headers="construct characters"><tt>\x</tt><i>hh</i></td>
99 * <td headers="matches">The character with hexadecimal value <tt>0x</tt><i>hh</i></td></tr>
100 * <tr><td valign="top" headers="construct characters"><tt>\u</tt><i>hhhh</i></td>
101 * <td headers="matches">The character with hexadecimal value <tt>0x</tt><i>hhhh</i></td></tr>
102 * <tr><td valign="top" headers="matches"><tt>\t</tt></td>
103 * <td headers="matches">The tab character (<tt>'\u0009'</tt>)</td></tr>
104 * <tr><td valign="top" headers="construct characters"><tt>\n</tt></td>
105 * <td headers="matches">The newline (line feed) character (<tt>'\u000A'</tt>)</td></tr>
106 * <tr><td valign="top" headers="construct characters"><tt>\r</tt></td>
107 * <td headers="matches">The carriage-return character (<tt>'\u000D'</tt>)</td></tr>
108 * <tr><td valign="top" headers="construct characters"><tt>\f</tt></td>
109 * <td headers="matches">The form-feed character (<tt>'\u000C'</tt>)</td></tr>
110 * <tr><td valign="top" headers="construct characters"><tt>\a</tt></td>
111 * <td headers="matches">The alert (bell) character (<tt>'\u0007'</tt>)</td></tr>
112 * <tr><td valign="top" headers="construct characters"><tt>\e</tt></td>
113 * <td headers="matches">The escape character (<tt>'\u001B'</tt>)</td></tr>
114 * <tr><td valign="top" headers="construct characters"><tt>\c</tt><i>x</i></td>
115 * <td headers="matches">The control character corresponding to <i>x</i></td></tr>
116 *
117 * <tr><th> </th></tr>
118 * <tr align="left"><th colspan="2" id="classes">Character classes</th></tr>
119 *
120 * <tr><td valign="top" headers="construct classes"><tt>[abc]</tt></td>
121 * <td headers="matches"><tt>a</tt>, <tt>b</tt>, or <tt>c</tt> (simple class)</td></tr>
122 * <tr><td valign="top" headers="construct classes"><tt>[^abc]</tt></td>
123 * <td headers="matches">Any character except <tt>a</tt>, <tt>b</tt>, or <tt>c</tt> (negation)</td></tr>
124 * <tr><td valign="top" headers="construct classes"><tt>[a-zA-Z]</tt></td>
125 * <td headers="matches"><tt>a</tt> through <tt>z</tt>
126 * or <tt>A</tt> through <tt>Z</tt>, inclusive (range)</td></tr>
127 * <tr><td valign="top" headers="construct classes"><tt>[a-d[m-p]]</tt></td>
128 * <td headers="matches"><tt>a</tt> through <tt>d</tt>,
129 * or <tt>m</tt> through <tt>p</tt>: <tt>[a-dm-p]</tt> (union)</td></tr>
130 * <tr><td valign="top" headers="construct classes"><tt>[a-z&&[def]]</tt></td>
131 * <td headers="matches"><tt>d</tt>, <tt>e</tt>, or <tt>f</tt> (intersection)</tr>
132 * <tr><td valign="top" headers="construct classes"><tt>[a-z&&[^bc]]</tt></td>
133 * <td headers="matches"><tt>a</tt> through <tt>z</tt>,
134 * except for <tt>b</tt> and <tt>c</tt>: <tt>[ad-z]</tt> (subtraction)</td></tr>
135 * <tr><td valign="top" headers="construct classes"><tt>[a-z&&[^m-p]]</tt></td>
136 * <td headers="matches"><tt>a</tt> through <tt>z</tt>,
137 * and not <tt>m</tt> through <tt>p</tt>: <tt>[a-lq-z]</tt>(subtraction)</td></tr>
138 * <tr><th> </th></tr>
139 *
140 * <tr align="left"><th colspan="2" id="predef">Predefined character classes</th></tr>
141 *
142 * <tr><td valign="top" headers="construct predef"><tt>.</tt></td>
143 * <td headers="matches">Any character (may or may not match <a href="#lt">line terminators</a>)</td></tr>
144 * <tr><td valign="top" headers="construct predef"><tt>\d</tt></td>
145 * <td headers="matches">A digit: <tt>[0-9]</tt></td></tr>
146 * <tr><td valign="top" headers="construct predef"><tt>\D</tt></td>
147 * <td headers="matches">A non-digit: <tt>[^0-9]</tt></td></tr>
148 * <tr><td valign="top" headers="construct predef"><tt>\s</tt></td>
149 * <td headers="matches">A whitespace character: <tt>[ \t\n\x0B\f\r]</tt></td></tr>
150 * <tr><td valign="top" headers="construct predef"><tt>\S</tt></td>
151 * <td headers="matches">A non-whitespace character: <tt>[^\s]</tt></td></tr>
152 * <tr><td valign="top" headers="construct predef"><tt>\w</tt></td>
153 * <td headers="matches">A word character: <tt>[a-zA-Z_0-9]</tt></td></tr>
154 * <tr><td valign="top" headers="construct predef"><tt>\W</tt></td>
155 * <td headers="matches">A non-word character: <tt>[^\w]</tt></td></tr>
156 *
157 * <tr><th> </th></tr>
158 * <tr align="left"><th colspan="2" id="posix">POSIX character classes</b> (US-ASCII only)<b></th></tr>
159 *
160 * <tr><td valign="top" headers="construct posix"><tt>\p{Lower}</tt></td>
161 * <td headers="matches">A lower-case alphabetic character: <tt>[a-z]</tt></td></tr>
162 * <tr><td valign="top" headers="construct posix"><tt>\p{Upper}</tt></td>
163 * <td headers="matches">An upper-case alphabetic character:<tt>[A-Z]</tt></td></tr>
164 * <tr><td valign="top" headers="construct posix"><tt>\p{ASCII}</tt></td>
165 * <td headers="matches">All ASCII:<tt>[\x00-\x7F]</tt></td></tr>
166 * <tr><td valign="top" headers="construct posix"><tt>\p{Alpha}</tt></td>
167 * <td headers="matches">An alphabetic character:<tt>[\p{Lower}\p{Upper}]</tt></td></tr>
168 * <tr><td valign="top" headers="construct posix"><tt>\p{Digit}</tt></td>
169 * <td headers="matches">A decimal digit: <tt>[0-9]</tt></td></tr>
170 * <tr><td valign="top" headers="construct posix"><tt>\p{Alnum}</tt></td>
171 * <td headers="matches">An alphanumeric character:<tt>[\p{Alpha}\p{Digit}]</tt></td></tr>
172 * <tr><td valign="top" headers="construct posix"><tt>\p{Punct}</tt></td>
173 * <td headers="matches">Punctuation: One of <tt>!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~</tt></td></tr>
174 * <!-- <tt>[\!"#\$%&'\(\)\*\+,\-\./:;\<=\>\?@\[\\\]\^_`\{\|\}~]</tt>
175 * <tt>[\X21-\X2F\X31-\X40\X5B-\X60\X7B-\X7E]</tt> -->
176 * <tr><td valign="top" headers="construct posix"><tt>\p{Graph}</tt></td>
177 * <td headers="matches">A visible character: <tt>[\p{Alnum}\p{Punct}]</tt></td></tr>
178 * <tr><td valign="top" headers="construct posix"><tt>\p{Print}</tt></td>
179 * <td headers="matches">A printable character: <tt>[\p{Graph}\x20]</tt></td></tr>
180 * <tr><td valign="top" headers="construct posix"><tt>\p{Blank}</tt></td>
181 * <td headers="matches">A space or a tab: <tt>[ \t]</tt></td></tr>
182 * <tr><td valign="top" headers="construct posix"><tt>\p{Cntrl}</tt></td>
183 * <td headers="matches">A control character: <tt>[\x00-\x1F\x7F]</tt></td></tr>
184 * <tr><td valign="top" headers="construct posix"><tt>\p{XDigit}</tt></td>
185 * <td headers="matches">A hexadecimal digit: <tt>[0-9a-fA-F]</tt></td></tr>
186 * <tr><td valign="top" headers="construct posix"><tt>\p{Space}</tt></td>
187 * <td headers="matches">A whitespace character: <tt>[ \t\n\x0B\f\r]</tt></td></tr>
188 *
189 * <tr><th> </th></tr>
190 * <tr align="left"><th colspan="2">java.lang.Character classes (simple <a href="#jcc">java character type</a>)</th></tr>
191 *
192 * <tr><td valign="top"><tt>\p{javaLowerCase}</tt></td>
193 * <td>Equivalent to java.lang.Character.isLowerCase()</td></tr>
194 * <tr><td valign="top"><tt>\p{javaUpperCase}</tt></td>
195 * <td>Equivalent to java.lang.Character.isUpperCase()</td></tr>
196 * <tr><td valign="top"><tt>\p{javaWhitespace}</tt></td>
197 * <td>Equivalent to java.lang.Character.isWhitespace()</td></tr>
198 * <tr><td valign="top"><tt>\p{javaMirrored}</tt></td>
199 * <td>Equivalent to java.lang.Character.isMirrored()</td></tr>
200 *
201 * <tr><th> </th></tr>
202 * <tr align="left"><th colspan="2" id="unicode">Classes for Unicode blocks and categories</th></tr>
203 *
204 * <tr><td valign="top" headers="construct unicode"><tt>\p{InGreek}</tt></td>
205 * <td headers="matches">A character in the Greek block (simple <a href="#ubc">block</a>)</td></tr>
206 * <tr><td valign="top" headers="construct unicode"><tt>\p{Lu}</tt></td>
207 * <td headers="matches">An uppercase letter (simple <a href="#ubc">category</a>)</td></tr>
208 * <tr><td valign="top" headers="construct unicode"><tt>\p{Sc}</tt></td>
209 * <td headers="matches">A currency symbol</td></tr>
210 * <tr><td valign="top" headers="construct unicode"><tt>\P{InGreek}</tt></td>
211 * <td headers="matches">Any character except one in the Greek block (negation)</td></tr>
212 * <tr><td valign="top" headers="construct unicode"><tt>[\p{L}&&[^\p{Lu}]] </tt></td>
213 * <td headers="matches">Any letter except an uppercase letter (subtraction)</td></tr>
214 *
215 * <tr><th> </th></tr>
216 * <tr align="left"><th colspan="2" id="bounds">Boundary matchers</th></tr>
217 *
218 * <tr><td valign="top" headers="construct bounds"><tt>^</tt></td>
219 * <td headers="matches">The beginning of a line</td></tr>
220 * <tr><td valign="top" headers="construct bounds"><tt>$</tt></td>
221 * <td headers="matches">The end of a line</td></tr>
222 * <tr><td valign="top" headers="construct bounds"><tt>\b</tt></td>
223 * <td headers="matches">A word boundary</td></tr>
224 * <tr><td valign="top" headers="construct bounds"><tt>\B</tt></td>
225 * <td headers="matches">A non-word boundary</td></tr>
226 * <tr><td valign="top" headers="construct bounds"><tt>\A</tt></td>
227 * <td headers="matches">The beginning of the input</td></tr>
228 * <tr><td valign="top" headers="construct bounds"><tt>\G</tt></td>
229 * <td headers="matches">The end of the previous match</td></tr>
230 * <tr><td valign="top" headers="construct bounds"><tt>\Z</tt></td>
231 * <td headers="matches">The end of the input but for the final
232 * <a href="#lt">terminator</a>, if any</td></tr>
233 * <tr><td valign="top" headers="construct bounds"><tt>\z</tt></td>
234 * <td headers="matches">The end of the input</td></tr>
235 *
236 * <tr><th> </th></tr>
237 * <tr align="left"><th colspan="2" id="greedy">Greedy quantifiers</th></tr>
238 *
239 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>?</tt></td>
240 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
241 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>*</tt></td>
242 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
243 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>+</tt></td>
244 * <td headers="matches"><i>X</i>, one or more times</td></tr>
245 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>{</tt><i>n</i><tt>}</tt></td>
246 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
247 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>{</tt><i>n</i><tt>,}</tt></td>
248 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
249 * <tr><td valign="top" headers="construct greedy"><i>X</i><tt>{</tt><i>n</i><tt>,</tt><i>m</i><tt>}</tt></td>
250 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
251 *
252 * <tr><th> </th></tr>
253 * <tr align="left"><th colspan="2" id="reluc">Reluctant quantifiers</th></tr>
254 *
255 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>??</tt></td>
256 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
257 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>*?</tt></td>
258 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
259 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>+?</tt></td>
260 * <td headers="matches"><i>X</i>, one or more times</td></tr>
261 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>{</tt><i>n</i><tt>}?</tt></td>
262 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
263 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>{</tt><i>n</i><tt>,}?</tt></td>
264 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
265 * <tr><td valign="top" headers="construct reluc"><i>X</i><tt>{</tt><i>n</i><tt>,</tt><i>m</i><tt>}?</tt></td>
266 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
267 *
268 * <tr><th> </th></tr>
269 * <tr align="left"><th colspan="2" id="poss">Possessive quantifiers</th></tr>
270 *
271 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>?+</tt></td>
272 * <td headers="matches"><i>X</i>, once or not at all</td></tr>
273 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>*+</tt></td>
274 * <td headers="matches"><i>X</i>, zero or more times</td></tr>
275 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>++</tt></td>
276 * <td headers="matches"><i>X</i>, one or more times</td></tr>
277 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>{</tt><i>n</i><tt>}+</tt></td>
278 * <td headers="matches"><i>X</i>, exactly <i>n</i> times</td></tr>
279 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>{</tt><i>n</i><tt>,}+</tt></td>
280 * <td headers="matches"><i>X</i>, at least <i>n</i> times</td></tr>
281 * <tr><td valign="top" headers="construct poss"><i>X</i><tt>{</tt><i>n</i><tt>,</tt><i>m</i><tt>}+</tt></td>
282 * <td headers="matches"><i>X</i>, at least <i>n</i> but not more than <i>m</i> times</td></tr>
283 *
284 * <tr><th> </th></tr>
285 * <tr align="left"><th colspan="2" id="logical">Logical operators</th></tr>
286 *
287 * <tr><td valign="top" headers="construct logical"><i>XY</i></td>
288 * <td headers="matches"><i>X</i> followed by <i>Y</i></td></tr>
289 * <tr><td valign="top" headers="construct logical"><i>X</i><tt>|</tt><i>Y</i></td>
290 * <td headers="matches">Either <i>X</i> or <i>Y</i></td></tr>
291 * <tr><td valign="top" headers="construct logical"><tt>(</tt><i>X</i><tt>)</tt></td>
292 * <td headers="matches">X, as a <a href="#cg">capturing group</a></td></tr>
293 *
294 * <tr><th> </th></tr>
295 * <tr align="left"><th colspan="2" id="backref">Back references</th></tr>
296 *
297 * <tr><td valign="bottom" headers="construct backref"><tt>\</tt><i>n</i></td>
298 * <td valign="bottom" headers="matches">Whatever the <i>n</i><sup>th</sup>
299 * <a href="#cg">capturing group</a> matched</td></tr>
300 *
301 * <tr><th> </th></tr>
302 * <tr align="left"><th colspan="2" id="quot">Quotation</th></tr>
303 *
304 * <tr><td valign="top" headers="construct quot"><tt>\</tt></td>
305 * <td headers="matches">Nothing, but quotes the following character</td></tr>
306 * <tr><td valign="top" headers="construct quot"><tt>\Q</tt></td>
307 * <td headers="matches">Nothing, but quotes all characters until <tt>\E</tt></td></tr>
308 * <tr><td valign="top" headers="construct quot"><tt>\E</tt></td>
309 * <td headers="matches">Nothing, but ends quoting started by <tt>\Q</tt></td></tr>
310 * <!-- Metachars: !$()*+.<>?[\]^{|} -->
311 *
312 * <tr><th> </th></tr>
313 * <tr align="left"><th colspan="2" id="special">Special constructs (non-capturing)</th></tr>
314 *
315 * <tr><td valign="top" headers="construct special"><tt>(?:</tt><i>X</i><tt>)</tt></td>
316 * <td headers="matches"><i>X</i>, as a non-capturing group</td></tr>
317 * <tr><td valign="top" headers="construct special"><tt>(?idmsux-idmsux) </tt></td>
318 * <td headers="matches">Nothing, but turns match flags <a href="#CASE_INSENSITIVE">i</a>
319 * <a href="#UNIX_LINES">d</a> <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a>
320 * <a href="#UNICODE_CASE">u</a> <a href="#COMMENTS">x</a> on - off</td></tr>
321 * <tr><td valign="top" headers="construct special"><tt>(?idmsux-idmsux:</tt><i>X</i><tt>)</tt> </td>
322 * <td headers="matches"><i>X</i>, as a <a href="#cg">non-capturing group</a> with the
323 * given flags <a href="#CASE_INSENSITIVE">i</a> <a href="#UNIX_LINES">d</a>
324 * <a href="#MULTILINE">m</a> <a href="#DOTALL">s</a> <a href="#UNICODE_CASE">u</a >
325 * <a href="#COMMENTS">x</a> on - off</td></tr>
326 * <tr><td valign="top" headers="construct special"><tt>(?=</tt><i>X</i><tt>)</tt></td>
327 * <td headers="matches"><i>X</i>, via zero-width positive lookahead</td></tr>
328 * <tr><td valign="top" headers="construct special"><tt>(?!</tt><i>X</i><tt>)</tt></td>
329 * <td headers="matches"><i>X</i>, via zero-width negative lookahead</td></tr>
330 * <tr><td valign="top" headers="construct special"><tt>(?<=</tt><i>X</i><tt>)</tt></td>
331 * <td headers="matches"><i>X</i>, via zero-width positive lookbehind</td></tr>
332 * <tr><td valign="top" headers="construct special"><tt>(?<!</tt><i>X</i><tt>)</tt></td>
333 * <td headers="matches"><i>X</i>, via zero-width negative lookbehind</td></tr>
334 * <tr><td valign="top" headers="construct special"><tt>(?></tt><i>X</i><tt>)</tt></td>
335 * <td headers="matches"><i>X</i>, as an independent, non-capturing group</td></tr>
336 *
337 * </table>
338 *
339 * <hr>
340 *
341 *
342 * <a name="bs">
343 * <h4> Backslashes, escapes, and quoting </h4>
344 *
345 * <p> The backslash character (<tt>'\'</tt>) serves to introduce escaped
346 * constructs, as defined in the table above, as well as to quote characters
347 * that otherwise would be interpreted as unescaped constructs. Thus the
348 * expression <tt>\\</tt> matches a single backslash and <tt>\{</tt> matches a
349 * left brace.
350 *
351 * <p> It is an error to use a backslash prior to any alphabetic character that
352 * does not denote an escaped construct; these are reserved for future
353 * extensions to the regular-expression language. A backslash may be used
354 * prior to a non-alphabetic character regardless of whether that character is
355 * part of an unescaped construct.
356 *
357 * <p> Backslashes within string literals in Java source code are interpreted
358 * as required by the <a
359 * href="http://java.sun.com/docs/books/jls">Java Language
360 * Specification</a> as either <a
361 * href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#100850">Unicode
362 * escapes</a> or other <a
363 * href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#101089">character
364 * escapes</a>. It is therefore necessary to double backslashes in string
365 * literals that represent regular expressions to protect them from
366 * interpretation by the Java bytecode compiler. The string literal
367 * <tt>"\b"</tt>, for example, matches a single backspace character when
368 * interpreted as a regular expression, while <tt>"\\b"</tt> matches a
369 * word boundary. The string literal <tt>"\(hello\)"</tt> is illegal
370 * and leads to a compile-time error; in order to match the string
371 * <tt>(hello)</tt> the string literal <tt>"\\(hello\\)"</tt>
372 * must be used.
373 *
374 * <a name="cc">
375 * <h4> Character Classes </h4>
376 *
377 * <p> Character classes may appear within other character classes, and
378 * may be composed by the union operator (implicit) and the intersection
379 * operator (<tt>&&</tt>).
380 * The union operator denotes a class that contains every character that is
381 * in at least one of its operand classes. The intersection operator
382 * denotes a class that contains every character that is in both of its
383 * operand classes.
384 *
385 * <p> The precedence of character-class operators is as follows, from
386 * highest to lowest:
387 *
388 * <blockquote><table border="0" cellpadding="1" cellspacing="0"
389 * summary="Precedence of character class operators.">
390 * <tr><th>1 </th>
391 * <td>Literal escape </td>
392 * <td><tt>\x</tt></td></tr>
393 * <tr><th>2 </th>
394 * <td>Grouping</td>
395 * <td><tt>[...]</tt></td></tr>
396 * <tr><th>3 </th>
397 * <td>Range</td>
398 * <td><tt>a-z</tt></td></tr>
399 * <tr><th>4 </th>
400 * <td>Union</td>
401 * <td><tt>[a-e][i-u]</tt></td></tr>
402 * <tr><th>5 </th>
403 * <td>Intersection</td>
404 * <td><tt>[a-z&&[aeiou]]</tt></td></tr>
405 * </table></blockquote>
406 *
407 * <p> Note that a different set of metacharacters are in effect inside
408 * a character class than outside a character class. For instance, the
409 * regular expression <tt>.</tt> loses its special meaning inside a
410 * character class, while the expression <tt>-</tt> becomes a range
411 * forming metacharacter.
412 *
413 * <a name="lt">
414 * <h4> Line terminators </h4>
415 *
416 * <p> A <i>line terminator</i> is a one- or two-character sequence that marks
417 * the end of a line of the input character sequence. The following are
418 * recognized as line terminators:
419 *
420 * <ul>
421 *
422 * <li> A newline (line feed) character (<tt>'\n'</tt>),
423 *
424 * <li> A carriage-return character followed immediately by a newline
425 * character (<tt>"\r\n"</tt>),
426 *
427 * <li> A standalone carriage-return character (<tt>'\r'</tt>),
428 *
429 * <li> A next-line character (<tt>'\u0085'</tt>),
430 *
431 * <li> A line-separator character (<tt>'\u2028'</tt>), or
432 *
433 * <li> A paragraph-separator character (<tt>'\u2029</tt>).
434 *
435 * </ul>
436 * <p>If {@link #UNIX_LINES} mode is activated, then the only line terminators
437 * recognized are newline characters.
438 *
439 * <p> The regular expression <tt>.</tt> matches any character except a line
440 * terminator unless the {@link #DOTALL} flag is specified.
441 *
442 * <p> By default, the regular expressions <tt>^</tt> and <tt>$</tt> ignore
443 * line terminators and only match at the beginning and the end, respectively,
444 * of the entire input sequence. If {@link #MULTILINE} mode is activated then
445 * <tt>^</tt> matches at the beginning of input and after any line terminator
446 * except at the end of input. When in {@link #MULTILINE} mode <tt>$</tt>
447 * matches just before a line terminator or the end of the input sequence.
448 *
449 * <a name="cg">
450 * <h4> Groups and capturing </h4>
451 *
452 * <p> Capturing groups are numbered by counting their opening parentheses from
453 * left to right. In the expression <tt>((A)(B(C)))</tt>, for example, there
454 * are four such groups: </p>
455 *
456 * <blockquote><table cellpadding=1 cellspacing=0 summary="Capturing group numberings">
457 * <tr><th>1 </th>
458 * <td><tt>((A)(B(C)))</tt></td></tr>
459 * <tr><th>2 </th>
460 * <td><tt>(A)</tt></td></tr>
461 * <tr><th>3 </th>
462 * <td><tt>(B(C))</tt></td></tr>
463 * <tr><th>4 </th>
464 * <td><tt>(C)</tt></td></tr>
465 * </table></blockquote>
466 *
467 * <p> Group zero always stands for the entire expression.
468 *
469 * <p> Capturing groups are so named because, during a match, each subsequence
470 * of the input sequence that matches such a group is saved. The captured
471 * subsequence may be used later in the expression, via a back reference, and
472 * may also be retrieved from the matcher once the match operation is complete.
473 *
474 * <p> The captured input associated with a group is always the subsequence
475 * that the group most recently matched. If a group is evaluated a second time
476 * because of quantification then its previously-captured value, if any, will
477 * be retained if the second evaluation fails. Matching the string
478 * <tt>"aba"</tt> against the expression <tt>(a(b)?)+</tt>, for example, leaves
479 * group two set to <tt>"b"</tt>. All captured input is discarded at the
480 * beginning of each match.
481 *
482 * <p> Groups beginning with <tt>(?</tt> are pure, <i>non-capturing</i> groups
483 * that do not capture text and do not count towards the group total.
484 *
485 *
486 * <h4> Unicode support </h4>
487 *
488 * <p> This class is in conformance with Level 1 of <a
489 * href="http://www.unicode.org/reports/tr18/"><i>Unicode Technical
490 * Standard #18: Unicode Regular Expression Guidelines</i></a>, plus RL2.1
491 * Canonical Equivalents.
492 *
493 * <p> Unicode escape sequences such as <tt>\u2014</tt> in Java source code
494 * are processed as described in <a
495 * href="http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#100850">\u00A73.3</a>
496 * of the Java Language Specification. Such escape sequences are also
497 * implemented directly by the regular-expression parser so that Unicode
498 * escapes can be used in expressions that are read from files or from the
499 * keyboard. Thus the strings <tt>"\u2014"</tt> and <tt>"\\u2014"</tt>,
500 * while not equal, compile into the same pattern, which matches the character
501 * with hexadecimal value <tt>0x2014</tt>.
502 *
503 * <a name="ubc"> <p>Unicode blocks and categories are written with the
504 * <tt>\p</tt> and <tt>\P</tt> constructs as in
505 * Perl. <tt>\p{</tt><i>prop</i><tt>}</tt> matches if the input has the
506 * property <i>prop</i>, while <tt>\P{</tt><i>prop</i><tt>}</tt> does not match if
507 * the input has that property. Blocks are specified with the prefix
508 * <tt>In</tt>, as in <tt>InMongolian</tt>. Categories may be specified with
509 * the optional prefix <tt>Is</tt>: Both <tt>\p{L}</tt> and <tt>\p{IsL}</tt>
510 * denote the category of Unicode letters. Blocks and categories can be used
511 * both inside and outside of a character class.
512 *
513 * <p> The supported categories are those of
514 * <a href="http://www.unicode.org/unicode/standard/standard.html">
515 * <i>The Unicode Standard</i></a> in the version specified by the
516 * {@link java.lang.Character Character} class. The category names are those
517 * defined in the Standard, both normative and informative.
518 * The block names supported by <code>Pattern</code> are the valid block names
519 * accepted and defined by
520 * {@link java.lang.Character.UnicodeBlock#forName(String) UnicodeBlock.forName}.
521 *
522 * <a name="jcc"> <p>Categories that behave like the java.lang.Character
523 * boolean is<i>methodname</i> methods (except for the deprecated ones) are
524 * available through the same <tt>\p{</tt><i>prop</i><tt>}</tt> syntax where
525 * the specified property has the name <tt>java<i>methodname</i></tt>.
526 *
527 * <h4> Comparison to Perl 5 </h4>
528 *
529 * <p>The <code>Pattern</code> engine performs traditional NFA-based matching
530 * with ordered alternation as occurs in Perl 5.
531 *
532 * <p> Perl constructs not supported by this class: </p>
533 *
534 * <ul>
535 *
536 * <li><p> The conditional constructs <tt>(?{</tt><i>X</i><tt>})</tt> and
537 * <tt>(?(</tt><i>condition</i><tt>)</tt><i>X</i><tt>|</tt><i>Y</i><tt>)</tt>,
538 * </p></li>
539 *
540 * <li><p> The embedded code constructs <tt>(?{</tt><i>code</i><tt>})</tt>
541 * and <tt>(??{</tt><i>code</i><tt>})</tt>,</p></li>
542 *
543 * <li><p> The embedded comment syntax <tt>(?#comment)</tt>, and </p></li>
544 *
545 * <li><p> The preprocessing operations <tt>\l</tt> <tt>\u</tt>,
546 * <tt>\L</tt>, and <tt>\U</tt>. </p></li>
547 *
548 * </ul>
549 *
550 * <p> Constructs supported by this class but not by Perl: </p>
551 *
552 * <ul>
553 *
554 * <li><p> Possessive quantifiers, which greedily match as much as they can
555 * and do not back off, even when doing so would allow the overall match to
556 * succeed. </p></li>
557 *
558 * <li><p> Character-class union and intersection as described
559 * <a href="#cc">above</a>.</p></li>
560 *
561 * </ul>
562 *
563 * <p> Notable differences from Perl: </p>
564 *
565 * <ul>
566 *
567 * <li><p> In Perl, <tt>\1</tt> through <tt>\9</tt> are always interpreted
568 * as back references; a backslash-escaped number greater than <tt>9</tt> is
569 * treated as a back reference if at least that many subexpressions exist,
570 * otherwise it is interpreted, if possible, as an octal escape. In this
571 * class octal escapes must always begin with a zero. In this class,
572 * <tt>\1</tt> through <tt>\9</tt> are always interpreted as back
573 * references, and a larger number is accepted as a back reference if at
574 * least that many subexpressions exist at that point in the regular
575 * expression, otherwise the parser will drop digits until the number is
576 * smaller or equal to the existing number of groups or it is one digit.
577 * </p></li>
578 *
579 * <li><p> Perl uses the <tt>g</tt> flag to request a match that resumes
580 * where the last match left off. This functionality is provided implicitly
581 * by the {@link Matcher} class: Repeated invocations of the {@link
582 * Matcher#find find} method will resume where the last match left off,
583 * unless the matcher is reset. </p></li>
584 *
585 * <li><p> In Perl, embedded flags at the top level of an expression affect
586 * the whole expression. In this class, embedded flags always take effect
587 * at the point at which they appear, whether they are at the top level or
588 * within a group; in the latter case, flags are restored at the end of the
589 * group just as in Perl. </p></li>
590 *
591 * <li><p> Perl is forgiving about malformed matching constructs, as in the
592 * expression <tt>*a</tt>, as well as dangling brackets, as in the
593 * expression <tt>abc]</tt>, and treats them as literals. This
594 * class also accepts dangling brackets but is strict about dangling
595 * metacharacters like +, ? and *, and will throw a
596 * {@link PatternSyntaxException} if it encounters them. </p></li>
597 *
598 * </ul>
599 *
600 *
601 * <p> For a more precise description of the behavior of regular expression
602 * constructs, please see <a href="http://www.oreilly.com/catalog/regex3/">
603 * <i>Mastering Regular Expressions, 3nd Edition</i>, Jeffrey E. F. Friedl,
604 * O'Reilly and Associates, 2006.</a>
605 * </p>
606 *
607 * @see java.lang.String#split(String, int)
608 * @see java.lang.String#split(String)
609 *
610 * @author Mike McCloskey
611 * @author Mark Reinhold
612 * @author JSR-51 Expert Group
613 * @since 1.4
614 * @spec JSR-51
615 */
616
617 public final class Pattern
618 implements java.io.Serializable
619 {
620
621 /**
622 * Regular expression modifier values. Instead of being passed as
623 * arguments, they can also be passed as inline modifiers.
624 * For example, the following statements have the same effect.
625 * <pre>
626 * RegExp r1 = RegExp.compile("abc", Pattern.I|Pattern.M);
627 * RegExp r2 = RegExp.compile("(?im)abc", 0);
628 * </pre>
629 *
630 * The flags are duplicated so that the familiar Perl match flag
631 * names are available.
632 */
633
634 /**
635 * Enables Unix lines mode.
636 *
637 * <p> In this mode, only the <tt>'\n'</tt> line terminator is recognized
638 * in the behavior of <tt>.</tt>, <tt>^</tt>, and <tt>$</tt>.
639 *
640 * <p> Unix lines mode can also be enabled via the embedded flag
641 * expression <tt>(?d)</tt>.
642 */
643 public static final int UNIX_LINES = 0x01;
644
645 /**
646 * Enables case-insensitive matching.
647 *
648 * <p> By default, case-insensitive matching assumes that only characters
649 * in the US-ASCII charset are being matched. Unicode-aware
650 * case-insensitive matching can be enabled by specifying the {@link
651 * #UNICODE_CASE} flag in conjunction with this flag.
652 *
653 * <p> Case-insensitive matching can also be enabled via the embedded flag
654 * expression <tt>(?i)</tt>.
655 *
656 * <p> Specifying this flag may impose a slight performance penalty. </p>
657 */
658 public static final int CASE_INSENSITIVE = 0x02;
659
660 /**
661 * Permits whitespace and comments in pattern.
662 *
663 * <p> In this mode, whitespace is ignored, and embedded comments starting
664 * with <tt>#</tt> are ignored until the end of a line.
665 *
666 * <p> Comments mode can also be enabled via the embedded flag
667 * expression <tt>(?x)</tt>.
668 */
669 public static final int COMMENTS = 0x04;
670
671 /**
672 * Enables multiline mode.
673 *
674 * <p> In multiline mode the expressions <tt>^</tt> and <tt>$</tt> match
675 * just after or just before, respectively, a line terminator or the end of
676 * the input sequence. By default these expressions only match at the
677 * beginning and the end of the entire input sequence.
678 *
679 * <p> Multiline mode can also be enabled via the embedded flag
680 * expression <tt>(?m)</tt>. </p>
681 */
682 public static final int MULTILINE = 0x08;
683
684 /**
685 * Enables literal parsing of the pattern.
686 *
687 * <p> When this flag is specified then the input string that specifies
688 * the pattern is treated as a sequence of literal characters.
689 * Metacharacters or escape sequences in the input sequence will be
690 * given no special meaning.
691 *
692 * <p>The flags CASE_INSENSITIVE and UNICODE_CASE retain their impact on
693 * matching when used in conjunction with this flag. The other flags
694 * become superfluous.
695 *
696 * <p> There is no embedded flag character for enabling literal parsing.
697 * @since 1.5
698 */
699 public static final int LITERAL = 0x10;
700
701 /**
702 * Enables dotall mode.
703 *
704 * <p> In dotall mode, the expression <tt>.</tt> matches any character,
705 * including a line terminator. By default this expression does not match
706 * line terminators.
707 *
708 * <p> Dotall mode can also be enabled via the embedded flag
709 * expression <tt>(?s)</tt>. (The <tt>s</tt> is a mnemonic for
710 * "single-line" mode, which is what this is called in Perl.) </p>
711 */
712 public static final int DOTALL = 0x20;
713
714 /**
715 * Enables Unicode-aware case folding.
716 *
717 * <p> When this flag is specified then case-insensitive matching, when
718 * enabled by the {@link #CASE_INSENSITIVE} flag, is done in a manner
719 * consistent with the Unicode Standard. By default, case-insensitive
720 * matching assumes that only characters in the US-ASCII charset are being
721 * matched.
722 *
723 * <p> Unicode-aware case folding can also be enabled via the embedded flag
724 * expression <tt>(?u)</tt>.
725 *
726 * <p> Specifying this flag may impose a performance penalty. </p>
727 */
728 public static final int UNICODE_CASE = 0x40;
729
730 /**
731 * Enables canonical equivalence.
732 *
733 * <p> When this flag is specified then two characters will be considered
734 * to match if, and only if, their full canonical decompositions match.
735 * The expression <tt>"a\u030A"</tt>, for example, will match the
736 * string <tt>"\u00E5"</tt> when this flag is specified. By default,
737 * matching does not take canonical equivalence into account.
738 *
739 * <p> There is no embedded flag character for enabling canonical
740 * equivalence.
741 *
742 * <p> Specifying this flag may impose a performance penalty. </p>
743 */
744 public static final int CANON_EQ = 0x80;
745
746 /* Pattern has only two serialized components: The pattern string
747 * and the flags, which are all that is needed to recompile the pattern
748 * when it is deserialized.
749 */
750
751 /** use serialVersionUID from Merlin b59 for interoperability */
752 private static final long serialVersionUID = 5073258162644648461L;
753
754 /**
755 * The original regular-expression pattern string.
756 *
757 * @serial
758 */
759 private String pattern;
760
761 /**
762 * The original pattern flags.
763 *
764 * @serial
765 */
766 private int flags;
767
768 /**
769 * Boolean indicating this Pattern is compiled; this is necessary in order
770 * to lazily compile deserialized Patterns.
771 */
772 private transient volatile boolean compiled = false;
773
774 /**
775 * The normalized pattern string.
776 */
777 private transient String normalizedPattern;
778
779 /**
780 * The starting point of state machine for the find operation. This allows
781 * a match to start anywhere in the input.
782 */
783 transient Node root;
784
785 /**
786 * The root of object tree for a match operation. The pattern is matched
787 * at the beginning. This may include a find that uses BnM or a First
788 * node.
789 */
790 transient Node matchRoot;
791
792 /**
793 * Temporary storage used by parsing pattern slice.
794 */
795 transient int[] buffer;
796
797 /**
798 * Temporary storage used while parsing group references.
799 */
800 transient GroupHead[] groupNodes;
801
802 /**
803 * Temporary null terminated code point array used by pattern compiling.
804 */
805 private transient int[] temp;
806
807 /**
808 * The number of capturing groups in this Pattern. Used by matchers to
809 * allocate storage needed to perform a match.
810 */
811 transient int capturingGroupCount;
812
813 /**
814 * The local variable count used by parsing tree. Used by matchers to
815 * allocate storage needed to perform a match.
816 */
817 transient int localCount;
818
819 /**
820 * Index into the pattern string that keeps track of how much has been
821 * parsed.
822 */
823 private transient int cursor;
824
825 /**
826 * Holds the length of the pattern string.
827 */
828 private transient int patternLength;
829
830 /**
831 * Compiles the given regular expression into a pattern. </p>
832 *
833 * @param regex
834 * The expression to be compiled
835 *
836 * @throws PatternSyntaxException
837 * If the expression's syntax is invalid
838 */
839 public static Pattern compile(String regex) {
840 return new Pattern(regex, 0);
841 }
842
843 /**
844 * Compiles the given regular expression into a pattern with the given
845 * flags. </p>
846 *
847 * @param regex
848 * The expression to be compiled
849 *
850 * @param flags
851 * Match flags, a bit mask that may include
852 * {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
853 * {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
854 * {@link #LITERAL} and {@link #COMMENTS}
855 *
856 * @throws IllegalArgumentException
857 * If bit values other than those corresponding to the defined
858 * match flags are set in <tt>flags</tt>
859 *
860 * @throws PatternSyntaxException
861 * If the expression's syntax is invalid
862 */
863 public static Pattern compile(String regex, int flags) {
864 return new Pattern(regex, flags);
865 }
866
867 /**
868 * Returns the regular expression from which this pattern was compiled.
869 * </p>
870 *
871 * @return The source of this pattern
872 */
873 public String pattern() {
874 return pattern;
875 }
876
877 /**
878 * <p>Returns the string representation of this pattern. This
879 * is the regular expression from which this pattern was
880 * compiled.</p>
881 *
882 * @return The string representation of this pattern
883 * @since 1.5
884 */
885 public String toString() {
886 return pattern;
887 }
888
889 /**
890 * Creates a matcher that will match the given input against this pattern.
891 * </p>
892 *
893 * @param input
894 * The character sequence to be matched
895 *
896 * @return A new matcher for this pattern
897 */
898 public Matcher matcher(CharSequence input) {
899 if (!compiled) {
900 synchronized(this) {
901 if (!compiled)
902 compile();
903 }
904 }
905 Matcher m = new Matcher(this, input);
906 return m;
907 }
908
909 /**
910 * Returns this pattern's match flags. </p>
911 *
912 * @return The match flags specified when this pattern was compiled
913 */
914 public int flags() {
915 return flags;
916 }
917
918 /**
919 * Compiles the given regular expression and attempts to match the given
920 * input against it.
921 *
922 * <p> An invocation of this convenience method of the form
923 *
924 * <blockquote><pre>
925 * Pattern.matches(regex, input);</pre></blockquote>
926 *
927 * behaves in exactly the same way as the expression
928 *
929 * <blockquote><pre>
930 * Pattern.compile(regex).matcher(input).matches()</pre></blockquote>
931 *
932 * <p> If a pattern is to be used multiple times, compiling it once and reusing
933 * it will be more efficient than invoking this method each time. </p>
934 *
935 * @param regex
936 * The expression to be compiled
937 *
938 * @param input
939 * The character sequence to be matched
940 *
941 * @throws PatternSyntaxException
942 * If the expression's syntax is invalid
943 */
944 public static boolean matches(String regex, CharSequence input) {
945 Pattern p = Pattern.compile(regex);
946 Matcher m = p.matcher(input);
947 return m.matches();
948 }
949
950 /**
951 * Splits the given input sequence around matches of this pattern.
952 *
953 * <p> The array returned by this method contains each substring of the
954 * input sequence that is terminated by another subsequence that matches
955 * this pattern or is terminated by the end of the input sequence. The
956 * substrings in the array are in the order in which they occur in the
957 * input. If this pattern does not match any subsequence of the input then
958 * the resulting array has just one element, namely the input sequence in
959 * string form.
960 *
961 * <p> The <tt>limit</tt> parameter controls the number of times the
962 * pattern is applied and therefore affects the length of the resulting
963 * array. If the limit <i>n</i> is greater than zero then the pattern
964 * will be applied at most <i>n</i> - 1 times, the array's
965 * length will be no greater than <i>n</i>, and the array's last entry
966 * will contain all input beyond the last matched delimiter. If <i>n</i>
967 * is non-positive then the pattern will be applied as many times as
968 * possible and the array can have any length. If <i>n</i> is zero then
969 * the pattern will be applied as many times as possible, the array can
970 * have any length, and trailing empty strings will be discarded.
971 *
972 * <p> The input <tt>"boo:and:foo"</tt>, for example, yields the following
973 * results with these parameters:
974 *
975 * <blockquote><table cellpadding=1 cellspacing=0
976 * summary="Split examples showing regex, limit, and result">
977 * <tr><th><P align="left"><i>Regex </i></th>
978 * <th><P align="left"><i>Limit </i></th>
979 * <th><P align="left"><i>Result </i></th></tr>
980 * <tr><td align=center>:</td>
981 * <td align=center>2</td>
982 * <td><tt>{ "boo", "and:foo" }</tt></td></tr>
983 * <tr><td align=center>:</td>
984 * <td align=center>5</td>
985 * <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
986 * <tr><td align=center>:</td>
987 * <td align=center>-2</td>
988 * <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
989 * <tr><td align=center>o</td>
990 * <td align=center>5</td>
991 * <td><tt>{ "b", "", ":and:f", "", "" }</tt></td></tr>
992 * <tr><td align=center>o</td>
993 * <td align=center>-2</td>
994 * <td><tt>{ "b", "", ":and:f", "", "" }</tt></td></tr>
995 * <tr><td align=center>o</td>
996 * <td align=center>0</td>
997 * <td><tt>{ "b", "", ":and:f" }</tt></td></tr>
998 * </table></blockquote>
999 *
1000 *
1001 * @param input
1002 * The character sequence to be split
1003 *
1004 * @param limit
1005 * The result threshold, as described above
1006 *
1007 * @return The array of strings computed by splitting the input
1008 * around matches of this pattern
1009 */
1010 public String[] split(CharSequence input, int limit) {
1011 int index = 0;
1012 boolean matchLimited = limit > 0;
1013 ArrayList<String> matchList = new ArrayList<String>();
1014 Matcher m = matcher(input);
1015
1016 // Add segments before each match found
1017 while(m.find()) {
1018 if (!matchLimited || matchList.size() < limit - 1) {
1019 String match = input.subSequence(index, m.start()).toString();
1020 matchList.add(match);
1021 index = m.end();
1022 } else if (matchList.size() == limit - 1) { // last one
1023 String match = input.subSequence(index,
1024 input.length()).toString();
1025 matchList.add(match);
1026 index = m.end();
1027 }
1028 }
1029
1030 // If no match was found, return this
1031 if (index == 0)
1032 return new String[] {input.toString()};
1033
1034 // Add remaining segment
1035 if (!matchLimited || matchList.size() < limit)
1036 matchList.add(input.subSequence(index, input.length()).toString());
1037
1038 // Construct result
1039 int resultSize = matchList.size();
1040 if (limit == 0)
1041 while (resultSize > 0 && matchList.get(resultSize-1).equals(""))
1042 resultSize--;
1043 String[] result = new String[resultSize];
1044 return matchList.subList(0, resultSize).toArray(result);
1045 }
1046
1047 /**
1048 * Splits the given input sequence around matches of this pattern.
1049 *
1050 * <p> This method works as if by invoking the two-argument {@link
1051 * #split(java.lang.CharSequence, int) split} method with the given input
1052 * sequence and a limit argument of zero. Trailing empty strings are
1053 * therefore not included in the resulting array. </p>
1054 *
1055 * <p> The input <tt>"boo:and:foo"</tt>, for example, yields the following
1056 * results with these expressions:
1057 *
1058 * <blockquote><table cellpadding=1 cellspacing=0
1059 * summary="Split examples showing regex and result">
1060 * <tr><th><P align="left"><i>Regex </i></th>
1061 * <th><P align="left"><i>Result</i></th></tr>
1062 * <tr><td align=center>:</td>
1063 * <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
1064 * <tr><td align=center>o</td>
1065 * <td><tt>{ "b", "", ":and:f" }</tt></td></tr>
1066 * </table></blockquote>
1067 *
1068 *
1069 * @param input
1070 * The character sequence to be split
1071 *
1072 * @return The array of strings computed by splitting the input
1073 * around matches of this pattern
1074 */
1075 public String[] split(CharSequence input) {
1076 return split(input, 0);
1077 }
1078
1079 /**
1080 * Returns a literal pattern <code>String</code> for the specified
1081 * <code>String</code>.
1082 *
1083 * <p>This method produces a <code>String</code> that can be used to
1084 * create a <code>Pattern</code> that would match the string
1085 * <code>s</code> as if it were a literal pattern.</p> Metacharacters
1086 * or escape sequences in the input sequence will be given no special
1087 * meaning.
1088 *
1089 * @param s The string to be literalized
1090 * @return A literal string replacement
1091 * @since 1.5
1092 */
1093 public static String quote(String s) {
1094 int slashEIndex = s.indexOf("\\E");
1095 if (slashEIndex == -1)
1096 return "\\Q" + s + "\\E";
1097
1098 StringBuilder sb = new StringBuilder(s.length() * 2);
1099 sb.append("\\Q");
1100 slashEIndex = 0;
1101 int current = 0;
1102 while ((slashEIndex = s.indexOf("\\E", current)) != -1) {
1103 sb.append(s.substring(current, slashEIndex));
1104 current = slashEIndex + 2;
1105 sb.append("\\E\\\\E\\Q");
1106 }
1107 sb.append(s.substring(current, s.length()));
1108 sb.append("\\E");
1109 return sb.toString();
1110 }
1111
1112 /**
1113 * Recompile the Pattern instance from a stream. The original pattern
1114 * string is read in and the object tree is recompiled from it.
1115 */
1116 private void readObject(java.io.ObjectInputStream s)
1117 throws java.io.IOException, ClassNotFoundException {
1118
1119 // Read in all fields
1120 s.defaultReadObject();
1121
1122 // Initialize counts
1123 capturingGroupCount = 1;
1124 localCount = 0;
1125
1126 // if length > 0, the Pattern is lazily compiled
1127 compiled = false;
1128 if (pattern.length() == 0) {
1129 root = new Start(lastAccept);
1130 matchRoot = lastAccept;
1131 compiled = true;
1132 }
1133 }
1134
1135 /**
1136 * This private constructor is used to create all Patterns. The pattern
1137 * string and match flags are all that is needed to completely describe
1138 * a Pattern. An empty pattern string results in an object tree with
1139 * only a Start node and a LastNode node.
1140 */
1141 private Pattern(String p, int f) {
1142 pattern = p;
1143 flags = f;
1144
1145 // Reset group index count
1146 capturingGroupCount = 1;
1147 localCount = 0;
1148
1149 if (pattern.length() > 0) {
1150 compile();
1151 } else {
1152 root = new Start(lastAccept);
1153 matchRoot = lastAccept;
1154 }
1155 }
1156
1157 /**
1158 * The pattern is converted to normalizedD form and then a pure group
1159 * is constructed to match canonical equivalences of the characters.
1160 */
1161 private void normalize() {
1162 boolean inCharClass = false;
1163 int lastCodePoint = -1;
1164
1165 // Convert pattern into normalizedD form
1166 normalizedPattern = Normalizer.normalize(pattern, Normalizer.Form.NFD);
1167 patternLength = normalizedPattern.length();
1168
1169 // Modify pattern to match canonical equivalences
1170 StringBuilder newPattern = new StringBuilder(patternLength);
1171 for(int i=0; i<patternLength; ) {
1172 int c = normalizedPattern.codePointAt(i);
1173 StringBuilder sequenceBuffer;
1174 if ((Character.getType(c) == Character.NON_SPACING_MARK)
1175 && (lastCodePoint != -1)) {
1176 sequenceBuffer = new StringBuilder();
1177 sequenceBuffer.appendCodePoint(lastCodePoint);
1178 sequenceBuffer.appendCodePoint(c);
1179 while(Character.getType(c) == Character.NON_SPACING_MARK) {
1180 i += Character.charCount(c);
1181 if (i >= patternLength)
1182 break;
1183 c = normalizedPattern.codePointAt(i);
1184 sequenceBuffer.appendCodePoint(c);
1185 }
1186 String ea = produceEquivalentAlternation(
1187 sequenceBuffer.toString());
1188 newPattern.setLength(newPattern.length()-Character.charCount(lastCodePoint));
1189 newPattern.append("(?:").append(ea).append(")");
1190 } else if (c == '[' && lastCodePoint != '\\') {
1191 i = normalizeCharClass(newPattern, i);
1192 } else {
1193 newPattern.appendCodePoint(c);
1194 }
1195 lastCodePoint = c;
1196 i += Character.charCount(c);
1197 }
1198 normalizedPattern = newPattern.toString();
1199 }
1200
1201 /**
1202 * Complete the character class being parsed and add a set
1203 * of alternations to it that will match the canonical equivalences
1204 * of the characters within the class.
1205 */
1206 private int normalizeCharClass(StringBuilder newPattern, int i) {
1207 StringBuilder charClass = new StringBuilder();
1208 StringBuilder eq = null;
1209 int lastCodePoint = -1;
1210 String result;
1211
1212 i++;
1213 charClass.append("[");
1214 while(true) {
1215 int c = normalizedPattern.codePointAt(i);
1216 StringBuilder sequenceBuffer;
1217
1218 if (c == ']' && lastCodePoint != '\\') {
1219 charClass.append((char)c);
1220 break;
1221 } else if (Character.getType(c) == Character.NON_SPACING_MARK) {
1222 sequenceBuffer = new StringBuilder();
1223 sequenceBuffer.appendCodePoint(lastCodePoint);
1224 while(Character.getType(c) == Character.NON_SPACING_MARK) {
1225 sequenceBuffer.appendCodePoint(c);
1226 i += Character.charCount(c);
1227 if (i >= normalizedPattern.length())
1228 break;
1229 c = normalizedPattern.codePointAt(i);
1230 }
1231 String ea = produceEquivalentAlternation(
1232 sequenceBuffer.toString());
1233
1234 charClass.setLength(charClass.length()-Character.charCount(lastCodePoint));
1235 if (eq == null)
1236 eq = new StringBuilder();
1237 eq.append('|');
1238 eq.append(ea);
1239 } else {
1240 charClass.appendCodePoint(c);
1241 i++;
1242 }
1243 if (i == normalizedPattern.length())
1244 throw error("Unclosed character class");
1245 lastCodePoint = c;
1246 }
1247
1248 if (eq != null) {
1249 result = "(?:"+charClass.toString()+eq.toString()+")";
1250 } else {
1251 result = charClass.toString();
1252 }
1253
1254 newPattern.append(result);
1255 return i;
1256 }
1257
1258 /**
1259 * Given a specific sequence composed of a regular character and
1260 * combining marks that follow it, produce the alternation that will
1261 * match all canonical equivalences of that sequence.
1262 */
1263 private String produceEquivalentAlternation(String source) {
1264 int len = countChars(source, 0, 1);
1265 if (source.length() == len)
1266 // source has one character.
1267 return source;
1268
1269 String base = source.substring(0,len);
1270 String combiningMarks = source.substring(len);
1271
1272 String[] perms = producePermutations(combiningMarks);
1273 StringBuilder result = new StringBuilder(source);
1274
1275 // Add combined permutations
1276 for(int x=0; x<perms.length; x++) {
1277 String next = base + perms[x];
1278 if (x>0)
1279 result.append("|"+next);
1280 next = composeOneStep(next);
1281 if (next != null)
1282 result.append("|"+produceEquivalentAlternation(next));
1283 }
1284 return result.toString();
1285 }
1286
1287 /**
1288 * Returns an array of strings that have all the possible
1289 * permutations of the characters in the input string.
1290 * This is used to get a list of all possible orderings
1291 * of a set of combining marks. Note that some of the permutations
1292 * are invalid because of combining class collisions, and these
1293 * possibilities must be removed because they are not canonically
1294 * equivalent.
1295 */
1296 private String[] producePermutations(String input) {
1297 if (input.length() == countChars(input, 0, 1))
1298 return new String[] {input};
1299
1300 if (input.length() == countChars(input, 0, 2)) {
1301 int c0 = Character.codePointAt(input, 0);
1302 int c1 = Character.codePointAt(input, Character.charCount(c0));
1303 if (getClass(c1) == getClass(c0)) {
1304 return new String[] {input};
1305 }
1306 String[] result = new String[2];
1307 result[0] = input;
1308 StringBuilder sb = new StringBuilder(2);
1309 sb.appendCodePoint(c1);
1310 sb.appendCodePoint(c0);
1311 result[1] = sb.toString();
1312 return result;
1313 }
1314
1315 int length = 1;
1316 int nCodePoints = countCodePoints(input);
1317 for(int x=1; x<nCodePoints; x++)
1318 length = length * (x+1);
1319
1320 String[] temp = new String[length];
1321
1322 int combClass[] = new int[nCodePoints];
1323 for(int x=0, i=0; x<nCodePoints; x++) {
1324 int c = Character.codePointAt(input, i);
1325 combClass[x] = getClass(c);
1326 i += Character.charCount(c);
1327 }
1328
1329 // For each char, take it out and add the permutations
1330 // of the remaining chars
1331 int index = 0;
1332 int len;
1333 // offset maintains the index in code units.
1334 loop: for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
1335 len = countChars(input, offset, 1);
1336 boolean skip = false;
1337 for(int y=x-1; y>=0; y--) {
1338 if (combClass[y] == combClass[x]) {
1339 continue loop;
1340 }
1341 }
1342 StringBuilder sb = new StringBuilder(input);
1343 String otherChars = sb.delete(offset, offset+len).toString();
1344 String[] subResult = producePermutations(otherChars);
1345
1346 String prefix = input.substring(offset, offset+len);
1347 for(int y=0; y<subResult.length; y++)
1348 temp[index++] = prefix + subResult[y];
1349 }
1350 String[] result = new String[index];
1351 for (int x=0; x<index; x++)
1352 result[x] = temp[x];
1353 return result;
1354 }
1355
1356 private int getClass(int c) {
1357 return sun.text.Normalizer.getCombiningClass(c);
1358 }
1359
1360 /**
1361 * Attempts to compose input by combining the first character
1362 * with the first combining mark following it. Returns a String
1363 * that is the composition of the leading character with its first
1364 * combining mark followed by the remaining combining marks. Returns
1365 * null if the first two characters cannot be further composed.
1366 */
1367 private String composeOneStep(String input) {
1368 int len = countChars(input, 0, 2);
1369 String firstTwoCharacters = input.substring(0, len);
1370 String result = Normalizer.normalize(firstTwoCharacters, Normalizer.Form.NFC);
1371
1372 if (result.equals(firstTwoCharacters))
1373 return null;
1374 else {
1375 String remainder = input.substring(len);
1376 return result + remainder;
1377 }
1378 }
1379
1380 /**
1381 * Preprocess any \Q...\E sequences in `temp', meta-quoting them.
1382 * See the description of `quotemeta' in perlfunc(1).
1383 */
1384 private void RemoveQEQuoting() {
1385 final int pLen = patternLength;
1386 int i = 0;
1387 while (i < pLen-1) {
1388 if (temp[i] != '\\')
1389 i += 1;
1390 else if (temp[i + 1] != 'Q')
1391 i += 2;
1392 else
1393 break;
1394 }
1395 if (i >= pLen - 1) // No \Q sequence found
1396 return;
1397 int j = i;
1398 i += 2;
1399 int[] newtemp = new int[j + 2*(pLen-i) + 2];
1400 System.arraycopy(temp, 0, newtemp, 0, j);
1401
1402 boolean inQuote = true;
1403 while (i < pLen) {
1404 int c = temp[i++];
1405 if (! ASCII.isAscii(c) || ASCII.isAlnum(c)) {
1406 newtemp[j++] = c;
1407 } else if (c != '\\') {
1408 if (inQuote) newtemp[j++] = '\\';
1409 newtemp[j++] = c;
1410 } else if (inQuote) {
1411 if (temp[i] == 'E') {
1412 i++;
1413 inQuote = false;
1414 } else {
1415 newtemp[j++] = '\\';
1416 newtemp[j++] = '\\';
1417 }
1418 } else {
1419 if (temp[i] == 'Q') {
1420 i++;
1421 inQuote = true;
1422 } else {
1423 newtemp[j++] = c;
1424 if (i != pLen)
1425 newtemp[j++] = temp[i++];
1426 }
1427 }
1428 }
1429
1430 patternLength = j;
1431 temp = Arrays.copyOf(newtemp, j + 2); // double zero termination
1432 }
1433
1434 /**
1435 * Copies regular expression to an int array and invokes the parsing
1436 * of the expression which will create the object tree.
1437 */
1438 private void compile() {
1439 // Handle canonical equivalences
1440 if (has(CANON_EQ) && !has(LITERAL)) {
1441 normalize();
1442 } else {
1443 normalizedPattern = pattern;
1444 }
1445 patternLength = normalizedPattern.length();
1446
1447 // Copy pattern to int array for convenience
1448 // Use double zero to terminate pattern
1449 temp = new int[patternLength + 2];
1450
1451 boolean hasSupplementary = false;
1452 int c, count = 0;
1453 // Convert all chars into code points
1454 for (int x = 0; x < patternLength; x += Character.charCount(c)) {
1455 c = normalizedPattern.codePointAt(x);
1456 if (isSupplementary(c)) {
1457 hasSupplementary = true;
1458 }
1459 temp[count++] = c;
1460 }
1461
1462 patternLength = count; // patternLength now in code points
1463
1464 if (! has(LITERAL))
1465 RemoveQEQuoting();
1466
1467 // Allocate all temporary objects here.
1468 buffer = new int[32];
1469 groupNodes = new GroupHead[10];
1470
1471 if (has(LITERAL)) {
1472 // Literal pattern handling
1473 matchRoot = newSlice(temp, patternLength, hasSupplementary);
1474 matchRoot.next = lastAccept;
1475 } else {
1476 // Start recursive descent parsing
1477 matchRoot = expr(lastAccept);
1478 // Check extra pattern characters
1479 if (patternLength != cursor) {
1480 if (peek() == ')') {
1481 throw error("Unmatched closing ')'");
1482 } else {
1483 throw error("Unexpected internal error");
1484 }
1485 }
1486 }
1487
1488 // Peephole optimization
1489 if (matchRoot instanceof Slice) {
1490 root = BnM.optimize(matchRoot);
1491 if (root == matchRoot) {
1492 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1493 }
1494 } else if (matchRoot instanceof Begin || matchRoot instanceof First) {
1495 root = matchRoot;
1496 } else {
1497 root = hasSupplementary ? new StartS(matchRoot) : new Start(matchRoot);
1498 }
1499
1500 // Release temporary storage
1501 temp = null;
1502 buffer = null;
1503 groupNodes = null;
1504 patternLength = 0;
1505 compiled = true;
1506 }
1507
1508 /**
1509 * Used to print out a subtree of the Pattern to help with debugging.
1510 */
1511 private static void printObjectTree(Node node) {
1512 while(node != null) {
1513 if (node instanceof Prolog) {
1514 System.out.println(node);
1515 printObjectTree(((Prolog)node).loop);
1516 System.out.println("**** end contents prolog loop");
1517 } else if (node instanceof Loop) {
1518 System.out.println(node);
1519 printObjectTree(((Loop)node).body);
1520 System.out.println("**** end contents Loop body");
1521 } else if (node instanceof Curly) {
1522 System.out.println(node);
1523 printObjectTree(((Curly)node).atom);
1524 System.out.println("**** end contents Curly body");
1525 } else if (node instanceof GroupCurly) {
1526 System.out.println(node);
1527 printObjectTree(((GroupCurly)node).atom);
1528 System.out.println("**** end contents GroupCurly body");
1529 } else if (node instanceof GroupTail) {
1530 System.out.println(node);
1531 System.out.println("Tail next is "+node.next);
1532 return;
1533 } else {
1534 System.out.println(node);
1535 }
1536 node = node.next;
1537 if (node != null)
1538 System.out.println("->next:");
1539 if (node == Pattern.accept) {
1540 System.out.println("Accept Node");
1541 node = null;
1542 }
1543 }
1544 }
1545
1546 /**
1547 * Used to accumulate information about a subtree of the object graph
1548 * so that optimizations can be applied to the subtree.
1549 */
1550 static final class TreeInfo {
1551 int minLength;
1552 int maxLength;
1553 boolean maxValid;
1554 boolean deterministic;
1555
1556 TreeInfo() {
1557 reset();
1558 }
1559 void reset() {
1560 minLength = 0;
1561 maxLength = 0;
1562 maxValid = true;
1563 deterministic = true;
1564 }
1565 }
1566
1567 /*
1568 * The following private methods are mainly used to improve the
1569 * readability of the code. In order to let the Java compiler easily
1570 * inline them, we should not put many assertions or error checks in them.
1571 */
1572
1573 /**
1574 * Indicates whether a particular flag is set or not.
1575 */
1576 private boolean has(int f) {
1577 return (flags & f) != 0;
1578 }
1579
1580 /**
1581 * Match next character, signal error if failed.
1582 */
1583 private void accept(int ch, String s) {
1584 int testChar = temp[cursor++];
1585 if (has(COMMENTS))
1586 testChar = parsePastWhitespace(testChar);
1587 if (ch != testChar) {
1588 throw error(s);
1589 }
1590 }
1591
1592 /**
1593 * Mark the end of pattern with a specific character.
1594 */
1595 private void mark(int c) {
1596 temp[patternLength] = c;
1597 }
1598
1599 /**
1600 * Peek the next character, and do not advance the cursor.
1601 */
1602 private int peek() {
1603 int ch = temp[cursor];
1604 if (has(COMMENTS))
1605 ch = peekPastWhitespace(ch);
1606 return ch;
1607 }
1608
1609 /**
1610 * Read the next character, and advance the cursor by one.
1611 */
1612 private int read() {
1613 int ch = temp[cursor++];
1614 if (has(COMMENTS))
1615 ch = parsePastWhitespace(ch);
1616 return ch;
1617 }
1618
1619 /**
1620 * Read the next character, and advance the cursor by one,
1621 * ignoring the COMMENTS setting
1622 */
1623 private int readEscaped() {
1624 int ch = temp[cursor++];
1625 return ch;
1626 }
1627
1628 /**
1629 * Advance the cursor by one, and peek the next character.
1630 */
1631 private int next() {
1632 int ch = temp[++cursor];
1633 if (has(COMMENTS))
1634 ch = peekPastWhitespace(ch);
1635 return ch;
1636 }
1637
1638 /**
1639 * Advance the cursor by one, and peek the next character,
1640 * ignoring the COMMENTS setting
1641 */
1642 private int nextEscaped() {
1643 int ch = temp[++cursor];
1644 return ch;
1645 }
1646
1647 /**
1648 * If in xmode peek past whitespace and comments.
1649 */
1650 private int peekPastWhitespace(int ch) {
1651 while (ASCII.isSpace(ch) || ch == '#') {
1652 while (ASCII.isSpace(ch))
1653 ch = temp[++cursor];
1654 if (ch == '#') {
1655 ch = peekPastLine();
1656 }
1657 }
1658 return ch;
1659 }
1660
1661 /**
1662 * If in xmode parse past whitespace and comments.
1663 */
1664 private int parsePastWhitespace(int ch) {
1665 while (ASCII.isSpace(ch) || ch == '#') {
1666 while (ASCII.isSpace(ch))
1667 ch = temp[cursor++];
1668 if (ch == '#')
1669 ch = parsePastLine();
1670 }
1671 return ch;
1672 }
1673
1674 /**
1675 * xmode parse past comment to end of line.
1676 */
1677 private int parsePastLine() {
1678 int ch = temp[cursor++];
1679 while (ch != 0 && !isLineSeparator(ch))
1680 ch = temp[cursor++];
1681 return ch;
1682 }
1683
1684 /**
1685 * xmode peek past comment to end of line.
1686 */
1687 private int peekPastLine() {
1688 int ch = temp[++cursor];
1689 while (ch != 0 && !isLineSeparator(ch))
1690 ch = temp[++cursor];
1691 return ch;
1692 }
1693
1694 /**
1695 * Determines if character is a line separator in the current mode
1696 */
1697 private boolean isLineSeparator(int ch) {
1698 if (has(UNIX_LINES)) {
1699 return ch == '\n';
1700 } else {
1701 return (ch == '\n' ||
1702 ch == '\r' ||
1703 (ch|1) == '\u2029' ||
1704 ch == '\u0085');
1705 }
1706 }
1707
1708 /**
1709 * Read the character after the next one, and advance the cursor by two.
1710 */
1711 private int skip() {
1712 int i = cursor;
1713 int ch = temp[i+1];
1714 cursor = i + 2;
1715 return ch;
1716 }
1717
1718 /**
1719 * Unread one next character, and retreat cursor by one.
1720 */
1721 private void unread() {
1722 cursor--;
1723 }
1724
1725 /**
1726 * Internal method used for handling all syntax errors. The pattern is
1727 * displayed with a pointer to aid in locating the syntax error.
1728 */
1729 private PatternSyntaxException error(String s) {
1730 return new PatternSyntaxException(s, normalizedPattern, cursor - 1);
1731 }
1732
1733 /**
1734 * Determines if there is any supplementary character or unpaired
1735 * surrogate in the specified range.
1736 */
1737 private boolean findSupplementary(int start, int end) {
1738 for (int i = start; i < end; i++) {
1739 if (isSupplementary(temp[i]))
1740 return true;
1741 }
1742 return false;
1743 }
1744
1745 /**
1746 * Determines if the specified code point is a supplementary
1747 * character or unpaired surrogate.
1748 */
1749 private static final boolean isSupplementary(int ch) {
1750 return ch >= Character.MIN_SUPPLEMENTARY_CODE_POINT || isSurrogate(ch);
1751 }
1752
1753 /**
1754 * The following methods handle the main parsing. They are sorted
1755 * according to their precedence order, the lowest one first.
1756 */
1757
1758 /**
1759 * The expression is parsed with branch nodes added for alternations.
1760 * This may be called recursively to parse sub expressions that may
1761 * contain alternations.
1762 */
1763 private Node expr(Node end) {
1764 Node prev = null;
1765 Node firstTail = null;
1766 Node branchConn = null;
1767
1768 for (;;) {
1769 Node node = sequence(end);
1770 Node nodeTail = root; //double return
1771 if (prev == null) {
1772 prev = node;
1773 firstTail = nodeTail;
1774 } else {
1775 // Branch
1776 if (branchConn == null) {
1777 branchConn = new BranchConn();
1778 branchConn.next = end;
1779 }
1780 if (node == end) {
1781 // if the node returned from sequence() is "end"
1782 // we have an empty expr, set a null atom into
1783 // the branch to indicate to go "next" directly.
1784 node = null;
1785 } else {
1786 // the "tail.next" of each atom goes to branchConn
1787 nodeTail.next = branchConn;
1788 }
1789 if (prev instanceof Branch) {
1790 ((Branch)prev).add(node);
1791 } else {
1792 if (prev == end) {
1793 prev = null;
1794 } else {
1795 // replace the "end" with "branchConn" at its tail.next
1796 // when put the "prev" into the branch as the first atom.
1797 firstTail.next = branchConn;
1798 }
1799 prev = new Branch(prev, node, branchConn);
1800 }
1801 }
1802 if (peek() != '|') {
1803 return prev;
1804 }
1805 next();
1806 }
1807 }
1808
1809 /**
1810 * Parsing of sequences between alternations.
1811 */
1812 private Node sequence(Node end) {
1813 Node head = null;
1814 Node tail = null;
1815 Node node = null;
1816 LOOP:
1817 for (;;) {
1818 int ch = peek();
1819 switch (ch) {
1820 case '(':
1821 // Because group handles its own closure,
1822 // we need to treat it differently
1823 node = group0();
1824 // Check for comment or flag group
1825 if (node == null)
1826 continue;
1827 if (head == null)
1828 head = node;
1829 else
1830 tail.next = node;
1831 // Double return: Tail was returned in root
1832 tail = root;
1833 continue;
1834 case '[':
1835 node = clazz(true);
1836 break;
1837 case '\\':
1838 ch = nextEscaped();
1839 if (ch == 'p' || ch == 'P') {
1840 boolean oneLetter = true;
1841 boolean comp = (ch == 'P');
1842 ch = next(); // Consume { if present
1843 if (ch != '{') {
1844 unread();
1845 } else {
1846 oneLetter = false;
1847 }
1848 node = family(oneLetter).maybeComplement(comp);
1849 } else {
1850 unread();
1851 node = atom();
1852 }
1853 break;
1854 case '^':
1855 next();
1856 if (has(MULTILINE)) {
1857 if (has(UNIX_LINES))
1858 node = new UnixCaret();
1859 else
1860 node = new Caret();
1861 } else {
1862 node = new Begin();
1863 }
1864 break;
1865 case '$':
1866 next();
1867 if (has(UNIX_LINES))
1868 node = new UnixDollar(has(MULTILINE));
1869 else
1870 node = new Dollar(has(MULTILINE));
1871 break;
1872 case '.':
1873 next();
1874 if (has(DOTALL)) {
1875 node = new All();
1876 } else {
1877 if (has(UNIX_LINES))
1878 node = new UnixDot();
1879 else {
1880 node = new Dot();
1881 }
1882 }
1883 break;
1884 case '|':
1885 case ')':
1886 break LOOP;
1887 case ']': // Now interpreting dangling ] and } as literals
1888 case '}':
1889 node = atom();
1890 break;
1891 case '?':
1892 case '*':
1893 case '+':
1894 next();
1895 throw error("Dangling meta character '" + ((char)ch) + "'");
1896 case 0:
1897 if (cursor >= patternLength) {
1898 break LOOP;
1899 }
1900 // Fall through
1901 default:
1902 node = atom();
1903 break;
1904 }
1905
1906 node = closure(node);
1907
1908 if (head == null) {
1909 head = tail = node;
1910 } else {
1911 tail.next = node;
1912 tail = node;
1913 }
1914 }
1915 if (head == null) {
1916 return end;
1917 }
1918 tail.next = end;
1919 root = tail; //double return
1920 return head;
1921 }
1922
1923 /**
1924 * Parse and add a new Single or Slice.
1925 */
1926 private Node atom() {
1927 int first = 0;
1928 int prev = -1;
1929 boolean hasSupplementary = false;
1930 int ch = peek();
1931 for (;;) {
1932 switch (ch) {
1933 case '*':
1934 case '+':
1935 case '?':
1936 case '{':
1937 if (first > 1) {
1938 cursor = prev; // Unwind one character
1939 first--;
1940 }
1941 break;
1942 case '$':
1943 case '.':
1944 case '^':
1945 case '(':
1946 case '[':
1947 case '|':
1948 case ')':
1949 break;
1950 case '\\':
1951 ch = nextEscaped();
1952 if (ch == 'p' || ch == 'P') { // Property
1953 if (first > 0) { // Slice is waiting; handle it first
1954 unread();
1955 break;
1956 } else { // No slice; just return the family node
1957 boolean comp = (ch == 'P');
1958 boolean oneLetter = true;
1959 ch = next(); // Consume { if present
1960 if (ch != '{')
1961 unread();
1962 else
1963 oneLetter = false;
1964 return family(oneLetter).maybeComplement(comp);
1965 }
1966 }
1967 unread();
1968 prev = cursor;
1969 ch = escape(false, first == 0);
1970 if (ch >= 0) {
1971 append(ch, first);
1972 first++;
1973 if (isSupplementary(ch)) {
1974 hasSupplementary = true;
1975 }
1976 ch = peek();
1977 continue;
1978 } else if (first == 0) {
1979 return root;
1980 }
1981 // Unwind meta escape sequence
1982 cursor = prev;
1983 break;
1984 case 0:
1985 if (cursor >= patternLength) {
1986 break;
1987 }
1988 // Fall through
1989 default:
1990 prev = cursor;
1991 append(ch, first);
1992 first++;
1993 if (isSupplementary(ch)) {
1994 hasSupplementary = true;
1995 }
1996 ch = next();
1997 continue;
1998 }
1999 break;
2000 }
2001 if (first == 1) {
2002 return newSingle(buffer[0]);
2003 } else {
2004 return newSlice(buffer, first, hasSupplementary);
2005 }
2006 }
2007
2008 private void append(int ch, int len) {
2009 if (len >= buffer.length) {
2010 int[] tmp = new int[len+len];
2011 System.arraycopy(buffer, 0, tmp, 0, len);
2012 buffer = tmp;
2013 }
2014 buffer[len] = ch;
2015 }
2016
2017 /**
2018 * Parses a backref greedily, taking as many numbers as it
2019 * can. The first digit is always treated as a backref, but
2020 * multi digit numbers are only treated as a backref if at
2021 * least that many backrefs exist at this point in the regex.
2022 */
2023 private Node ref(int refNum) {
2024 boolean done = false;
2025 while(!done) {
2026 int ch = peek();
2027 switch(ch) {
2028 case '0':
2029 case '1':
2030 case '2':
2031 case '3':
2032 case '4':
2033 case '5':
2034 case '6':
2035 case '7':
2036 case '8':
2037 case '9':
2038 int newRefNum = (refNum * 10) + (ch - '0');
2039 // Add another number if it doesn't make a group
2040 // that doesn't exist
2041 if (capturingGroupCount - 1 < newRefNum) {
2042 done = true;
2043 break;
2044 }
2045 refNum = newRefNum;
2046 read();
2047 break;
2048 default:
2049 done = true;
2050 break;
2051 }
2052 }
2053 if (has(CASE_INSENSITIVE))
2054 return new CIBackRef(refNum, has(UNICODE_CASE));
2055 else
2056 return new BackRef(refNum);
2057 }
2058
2059 /**
2060 * Parses an escape sequence to determine the actual value that needs
2061 * to be matched.
2062 * If -1 is returned and create was true a new object was added to the tree
2063 * to handle the escape sequence.
2064 * If the returned value is greater than zero, it is the value that
2065 * matches the escape sequence.
2066 */
2067 private int escape(boolean inclass, boolean create) {
2068 int ch = skip();
2069 switch (ch) {
2070 case '0':
2071 return o();
2072 case '1':
2073 case '2':
2074 case '3':
2075 case '4':
2076 case '5':
2077 case '6':
2078 case '7':
2079 case '8':
2080 case '9':
2081 if (inclass) break;
2082 if (create) {
2083 root = ref((ch - '0'));
2084 }
2085 return -1;
2086 case 'A':
2087 if (inclass) break;
2088 if (create) root = new Begin();
2089 return -1;
2090 case 'B':
2091 if (inclass) break;
2092 if (create) root = new Bound(Bound.NONE);
2093 return -1;
2094 case 'C':
2095 break;
2096 case 'D':
2097 if (create) root = new Ctype(ASCII.DIGIT).complement();
2098 return -1;
2099 case 'E':
2100 case 'F':
2101 break;
2102 case 'G':
2103 if (inclass) break;
2104 if (create) root = new LastMatch();
2105 return -1;
2106 case 'H':
2107 case 'I':
2108 case 'J':
2109 case 'K':
2110 case 'L':
2111 case 'M':
2112 case 'N':
2113 case 'O':
2114 case 'P':
2115 case 'Q':
2116 case 'R':
2117 break;
2118 case 'S':
2119 if (create) root = new Ctype(ASCII.SPACE).complement();
2120 return -1;
2121 case 'T':
2122 case 'U':
2123 case 'V':
2124 break;
2125 case 'W':
2126 if (create) root = new Ctype(ASCII.WORD).complement();
2127 return -1;
2128 case 'X':
2129 case 'Y':
2130 break;
2131 case 'Z':
2132 if (inclass) break;
2133 if (create) {
2134 if (has(UNIX_LINES))
2135 root = new UnixDollar(false);
2136 else
2137 root = new Dollar(false);
2138 }
2139 return -1;
2140 case 'a':
2141 return '\007';
2142 case 'b':
2143 if (inclass) break;
2144 if (create) root = new Bound(Bound.BOTH);
2145 return -1;
2146 case 'c':
2147 return c();
2148 case 'd':
2149 if (create) root = new Ctype(ASCII.DIGIT);
2150 return -1;
2151 case 'e':
2152 return '\033';
2153 case 'f':
2154 return '\f';
2155 case 'g':
2156 case 'h':
2157 case 'i':
2158 case 'j':
2159 case 'k':
2160 case 'l':
2161 case 'm':
2162 break;
2163 case 'n':
2164 return '\n';
2165 case 'o':
2166 case 'p':
2167 case 'q':
2168 break;
2169 case 'r':
2170 return '\r';
2171 case 's':
2172 if (create) root = new Ctype(ASCII.SPACE);
2173 return -1;
2174 case 't':
2175 return '\t';
2176 case 'u':
2177 return u();
2178 case 'v':
2179 return '\013';
2180 case 'w':
2181 if (create) root = new Ctype(ASCII.WORD);
2182 return -1;
2183 case 'x':
2184 return x();
2185 case 'y':
2186 break;
2187 case 'z':
2188 if (inclass) break;
2189 if (create) root = new End();
2190 return -1;
2191 default:
2192 return ch;
2193 }
2194 throw error("Illegal/unsupported escape sequence");
2195 }
2196
2197 /**
2198 * Parse a character class, and return the node that matches it.
2199 *
2200 * Consumes a ] on the way out if consume is true. Usually consume
2201 * is true except for the case of [abc&&def] where def is a separate
2202 * right hand node with "understood" brackets.
2203 */
2204 private CharProperty clazz(boolean consume) {
2205 CharProperty prev = null;
2206 CharProperty node = null;
2207 BitClass bits = new BitClass();
2208 boolean include = true;
2209 boolean firstInClass = true;
2210 int ch = next();
2211 for (;;) {
2212 switch (ch) {
2213 case '^':
2214 // Negates if first char in a class, otherwise literal
2215 if (firstInClass) {
2216 if (temp[cursor-1] != '[')
2217 break;
2218 ch = next();
2219 include = !include;
2220 continue;
2221 } else {
2222 // ^ not first in class, treat as literal
2223 break;
2224 }
2225 case '[':
2226 firstInClass = false;
2227 node = clazz(true);
2228 if (prev == null)
2229 prev = node;
2230 else
2231 prev = union(prev, node);
2232 ch = peek();
2233 continue;
2234 case '&':
2235 firstInClass = false;
2236 ch = next();
2237 if (ch == '&') {
2238 ch = next();
2239 CharProperty rightNode = null;
2240 while (ch != ']' && ch != '&') {
2241 if (ch == '[') {
2242 if (rightNode == null)
2243 rightNode = clazz(true);
2244 else
2245 rightNode = union(rightNode, clazz(true));
2246 } else { // abc&&def
2247 unread();
2248 rightNode = clazz(false);
2249 }
2250 ch = peek();
2251 }
2252 if (rightNode != null)
2253 node = rightNode;
2254 if (prev == null) {
2255 if (rightNode == null)
2256 throw error("Bad class syntax");
2257 else
2258 prev = rightNode;
2259 } else {
2260 prev = intersection(prev, node);
2261 }
2262 } else {
2263 // treat as a literal &
2264 unread();
2265 break;
2266 }
2267 continue;
2268 case 0:
2269 firstInClass = false;
2270 if (cursor >= patternLength)
2271 throw error("Unclosed character class");
2272 break;
2273 case ']':
2274 firstInClass = false;
2275 if (prev != null) {
2276 if (consume)
2277 next();
2278 return prev;
2279 }
2280 break;
2281 default:
2282 firstInClass = false;
2283 break;
2284 }
2285 node = range(bits);
2286 if (include) {
2287 if (prev == null) {
2288 prev = node;
2289 } else {
2290 if (prev != node)
2291 prev = union(prev, node);
2292 }
2293 } else {
2294 if (prev == null) {
2295 prev = node.complement();
2296 } else {
2297 if (prev != node)
2298 prev = setDifference(prev, node);
2299 }
2300 }
2301 ch = peek();
2302 }
2303 }
2304
2305 private CharProperty bitsOrSingle(BitClass bits, int ch) {
2306 /* Bits can only handle codepoints in [u+0000-u+00ff] range.
2307 Use "single" node instead of bits when dealing with unicode
2308 case folding for codepoints listed below.
2309 (1)Uppercase out of range: u+00ff, u+00b5
2310 toUpperCase(u+00ff) -> u+0178
2311 toUpperCase(u+00b5) -> u+039c
2312 (2)LatinSmallLetterLongS u+17f
2313 toUpperCase(u+017f) -> u+0053
2314 (3)LatinSmallLetterDotlessI u+131
2315 toUpperCase(u+0131) -> u+0049
2316 (4)LatinCapitalLetterIWithDotAbove u+0130
2317 toLowerCase(u+0130) -> u+0069
2318 (5)KelvinSign u+212a
2319 toLowerCase(u+212a) ==> u+006B
2320 (6)AngstromSign u+212b
2321 toLowerCase(u+212b) ==> u+00e5
2322 */
2323 int d;
2324 if (ch < 256 &&
2325 !(has(CASE_INSENSITIVE) && has(UNICODE_CASE) &&
2326 (ch == 0xff || ch == 0xb5 ||
2327 ch == 0x49 || ch == 0x69 || //I and i
2328 ch == 0x53 || ch == 0x73 || //S and s
2329 ch == 0x4b || ch == 0x6b || //K and k
2330 ch == 0xc5 || ch == 0xe5))) //A+ring
2331 return bits.add(ch, flags());
2332 return newSingle(ch);
2333 }
2334
2335 /**
2336 * Parse a single character or a character range in a character class
2337 * and return its representative node.
2338 */
2339 private CharProperty range(BitClass bits) {
2340 int ch = peek();
2341 if (ch == '\\') {
2342 ch = nextEscaped();
2343 if (ch == 'p' || ch == 'P') { // A property
2344 boolean comp = (ch == 'P');
2345 boolean oneLetter = true;
2346 // Consume { if present
2347 ch = next();
2348 if (ch != '{')
2349 unread();
2350 else
2351 oneLetter = false;
2352 return family(oneLetter).maybeComplement(comp);
2353 } else { // ordinary escape
2354 unread();
2355 ch = escape(true, true);
2356 if (ch == -1)
2357 return (CharProperty) root;
2358 }
2359 } else {
2360 ch = single();
2361 }
2362 if (ch >= 0) {
2363 if (peek() == '-') {
2364 int endRange = temp[cursor+1];
2365 if (endRange == '[') {
2366 return bitsOrSingle(bits, ch);
2367 }
2368 if (endRange != ']') {
2369 next();
2370 int m = single();
2371 if (m < ch)
2372 throw error("Illegal character range");
2373 if (has(CASE_INSENSITIVE))
2374 return caseInsensitiveRangeFor(ch, m);
2375 else
2376 return rangeFor(ch, m);
2377 }
2378 }
2379 return bitsOrSingle(bits, ch);
2380 }
2381 throw error("Unexpected character '"+((char)ch)+"'");
2382 }
2383
2384 private int single() {
2385 int ch = peek();
2386 switch (ch) {
2387 case '\\':
2388 return escape(true, false);
2389 default:
2390 next();
2391 return ch;
2392 }
2393 }
2394
2395 /**
2396 * Parses a Unicode character family and returns its representative node.
2397 */
2398 private CharProperty family(boolean singleLetter) {
2399 next();
2400 String name;
2401
2402 if (singleLetter) {
2403 int c = temp[cursor];
2404 if (!Character.isSupplementaryCodePoint(c)) {
2405 name = String.valueOf((char)c);
2406 } else {
2407 name = new String(temp, cursor, 1);
2408 }
2409 read();
2410 } else {
2411 int i = cursor;
2412 mark('}');
2413 while(read() != '}') {
2414 }
2415 mark('\000');
2416 int j = cursor;
2417 if (j > patternLength)
2418 throw error("Unclosed character family");
2419 if (i + 1 >= j)
2420 throw error("Empty character family");
2421 name = new String(temp, i, j-i-1);
2422 }
2423
2424 if (name.startsWith("In")) {
2425 return unicodeBlockPropertyFor(name.substring(2));
2426 } else {
2427 if (name.startsWith("Is"))
2428 name = name.substring(2);
2429 return charPropertyNodeFor(name);
2430 }
2431 }
2432
2433 /**
2434 * Returns a CharProperty matching all characters in a UnicodeBlock.
2435 */
2436 private CharProperty unicodeBlockPropertyFor(String name) {
2437 final Character.UnicodeBlock block;
2438 try {
2439 block = Character.UnicodeBlock.forName(name);
2440 } catch (IllegalArgumentException iae) {
2441 throw error("Unknown character block name {" + name + "}");
2442 }
2443 return new CharProperty() {
2444 boolean isSatisfiedBy(int ch) {
2445 return block == Character.UnicodeBlock.of(ch);}};
2446 }
2447
2448 /**
2449 * Returns a CharProperty matching all characters in a named property.
2450 */
2451 private CharProperty charPropertyNodeFor(String name) {
2452 CharProperty p = CharPropertyNames.charPropertyFor(name);
2453 if (p == null)
2454 throw error("Unknown character property name {" + name + "}");
2455 return p;
2456 }
2457
2458 /**
2459 * Parses a group and returns the head node of a set of nodes that process
2460 * the group. Sometimes a double return system is used where the tail is
2461 * returned in root.
2462 */
2463 private Node group0() {
2464 boolean capturingGroup = false;
2465 Node head = null;
2466 Node tail = null;
2467 int save = flags;
2468 root = null;
2469 int ch = next();
2470 if (ch == '?') {
2471 ch = skip();
2472 switch (ch) {
2473 case ':': // (?:xxx) pure group
2474 head = createGroup(true);
2475 tail = root;
2476 head.next = expr(tail);
2477 break;
2478 case '=': // (?=xxx) and (?!xxx) lookahead
2479 case '!':
2480 head = createGroup(true);
2481 tail = root;
2482 head.next = expr(tail);
2483 if (ch == '=') {
2484 head = tail = new Pos(head);
2485 } else {
2486 head = tail = new Neg(head);
2487 }
2488 break;
2489 case '>': // (?>xxx) independent group
2490 head = createGroup(true);
2491 tail = root;
2492 head.next = expr(tail);
2493 head = tail = new Ques(head, INDEPENDENT);
2494 break;
2495 case '<': // (?<xxx) look behind
2496 ch = read();
2497 int start = cursor;
2498 head = createGroup(true);
2499 tail = root;
2500 head.next = expr(tail);
2501 tail.next = lookbehindEnd;
2502 TreeInfo info = new TreeInfo();
2503 head.study(info);
2504 if (info.maxValid == false) {
2505 throw error("Look-behind group does not have "
2506 + "an obvious maximum length");
2507 }
2508 boolean hasSupplementary = findSupplementary(start, patternLength);
2509 if (ch == '=') {
2510 head = tail = (hasSupplementary ?
2511 new BehindS(head, info.maxLength,
2512 info.minLength) :
2513 new Behind(head, info.maxLength,
2514 info.minLength));
2515 } else if (ch == '!') {
2516 head = tail = (hasSupplementary ?
2517 new NotBehindS(head, info.maxLength,
2518 info.minLength) :
2519 new NotBehind(head, info.maxLength,
2520 info.minLength));
2521 } else {
2522 throw error("Unknown look-behind group");
2523 }
2524 break;
2525 case '$':
2526 case '@':
2527 throw error("Unknown group type");
2528 default: // (?xxx:) inlined match flags
2529 unread();
2530 addFlag();
2531 ch = read();
2532 if (ch == ')') {
2533 return null; // Inline modifier only
2534 }
2535 if (ch != ':') {
2536 throw error("Unknown inline modifier");
2537 }
2538 head = createGroup(true);
2539 tail = root;
2540 head.next = expr(tail);
2541 break;
2542 }
2543 } else { // (xxx) a regular group
2544 capturingGroup = true;
2545 head = createGroup(false);
2546 tail = root;
2547 head.next = expr(tail);
2548 }
2549
2550 accept(')', "Unclosed group");
2551 flags = save;
2552
2553 // Check for quantifiers
2554 Node node = closure(head);
2555 if (node == head) { // No closure
2556 root = tail;
2557 return node; // Dual return
2558 }
2559 if (head == tail) { // Zero length assertion
2560 root = node;
2561 return node; // Dual return
2562 }
2563
2564 if (node instanceof Ques) {
2565 Ques ques = (Ques) node;
2566 if (ques.type == POSSESSIVE) {
2567 root = node;
2568 return node;
2569 }
2570 tail.next = new BranchConn();
2571 tail = tail.next;
2572 if (ques.type == GREEDY) {
2573 head = new Branch(head, null, tail);
2574 } else { // Reluctant quantifier
2575 head = new Branch(null, head, tail);
2576 }
2577 root = tail;
2578 return head;
2579 } else if (node instanceof Curly) {
2580 Curly curly = (Curly) node;
2581 if (curly.type == POSSESSIVE) {
2582 root = node;
2583 return node;
2584 }
2585 // Discover if the group is deterministic
2586 TreeInfo info = new TreeInfo();
2587 if (head.study(info)) { // Deterministic
2588 GroupTail temp = (GroupTail) tail;
2589 head = root = new GroupCurly(head.next, curly.cmin,
2590 curly.cmax, curly.type,
2591 ((GroupTail)tail).localIndex,
2592 ((GroupTail)tail).groupIndex,
2593 capturingGroup);
2594 return head;
2595 } else { // Non-deterministic
2596 int temp = ((GroupHead) head).localIndex;
2597 Loop loop;
2598 if (curly.type == GREEDY)
2599 loop = new Loop(this.localCount, temp);
2600 else // Reluctant Curly
2601 loop = new LazyLoop(this.localCount, temp);
2602 Prolog prolog = new Prolog(loop);
2603 this.localCount += 1;
2604 loop.cmin = curly.cmin;
2605 loop.cmax = curly.cmax;
2606 loop.body = head;
2607 tail.next = loop;
2608 root = loop;
2609 return prolog; // Dual return
2610 }
2611 }
2612 throw error("Internal logic error");
2613 }
2614
2615 /**
2616 * Create group head and tail nodes using double return. If the group is
2617 * created with anonymous true then it is a pure group and should not
2618 * affect group counting.
2619 */
2620 private Node createGroup(boolean anonymous) {
2621 int localIndex = localCount++;
2622 int groupIndex = 0;
2623 if (!anonymous)
2624 groupIndex = capturingGroupCount++;
2625 GroupHead head = new GroupHead(localIndex);
2626 root = new GroupTail(localIndex, groupIndex);
2627 if (!anonymous && groupIndex < 10)
2628 groupNodes[groupIndex] = head;
2629 return head;
2630 }
2631
2632 /**
2633 * Parses inlined match flags and set them appropriately.
2634 */
2635 private void addFlag() {
2636 int ch = peek();
2637 for (;;) {
2638 switch (ch) {
2639 case 'i':
2640 flags |= CASE_INSENSITIVE;
2641 break;
2642 case 'm':
2643 flags |= MULTILINE;
2644 break;
2645 case 's':
2646 flags |= DOTALL;
2647 break;
2648 case 'd':
2649 flags |= UNIX_LINES;
2650 break;
2651 case 'u':
2652 flags |= UNICODE_CASE;
2653 break;
2654 case 'c':
2655 flags |= CANON_EQ;
2656 break;
2657 case 'x':
2658 flags |= COMMENTS;
2659 break;
2660 case '-': // subFlag then fall through
2661 ch = next();
2662 subFlag();
2663 default:
2664 return;
2665 }
2666 ch = next();
2667 }
2668 }
2669
2670 /**
2671 * Parses the second part of inlined match flags and turns off
2672 * flags appropriately.
2673 */
2674 private void subFlag() {
2675 int ch = peek();
2676 for (;;) {
2677 switch (ch) {
2678 case 'i':
2679 flags &= ~CASE_INSENSITIVE;
2680 break;
2681 case 'm':
2682 flags &= ~MULTILINE;
2683 break;
2684 case 's':
2685 flags &= ~DOTALL;
2686 break;
2687 case 'd':
2688 flags &= ~UNIX_LINES;
2689 break;
2690 case 'u':
2691 flags &= ~UNICODE_CASE;
2692 break;
2693 case 'c':
2694 flags &= ~CANON_EQ;
2695 break;
2696 case 'x':
2697 flags &= ~COMMENTS;
2698 break;
2699 default:
2700 return;
2701 }
2702 ch = next();
2703 }
2704 }
2705
2706 static final int MAX_REPS = 0x7FFFFFFF;
2707
2708 static final int GREEDY = 0;
2709
2710 static final int LAZY = 1;
2711
2712 static final int POSSESSIVE = 2;
2713
2714 static final int INDEPENDENT = 3;
2715
2716 /**
2717 * Processes repetition. If the next character peeked is a quantifier
2718 * then new nodes must be appended to handle the repetition.
2719 * Prev could be a single or a group, so it could be a chain of nodes.
2720 */
2721 private Node closure(Node prev) {
2722 Node atom;
2723 int ch = peek();
2724 switch (ch) {
2725 case '?':
2726 ch = next();
2727 if (ch == '?') {
2728 next();
2729 return new Ques(prev, LAZY);
2730 } else if (ch == '+') {
2731 next();
2732 return new Ques(prev, POSSESSIVE);
2733 }
2734 return new Ques(prev, GREEDY);
2735 case '*':
2736 ch = next();
2737 if (ch == '?') {
2738 next();
2739 return new Curly(prev, 0, MAX_REPS, LAZY);
2740 } else if (ch == '+') {
2741 next();
2742 return new Curly(prev, 0, MAX_REPS, POSSESSIVE);
2743 }
2744 return new Curly(prev, 0, MAX_REPS, GREEDY);
2745 case '+':
2746 ch = next();
2747 if (ch == '?') {
2748 next();
2749 return new Curly(prev, 1, MAX_REPS, LAZY);
2750 } else if (ch == '+') {
2751 next();
2752 return new Curly(prev, 1, MAX_REPS, POSSESSIVE);
2753 }
2754 return new Curly(prev, 1, MAX_REPS, GREEDY);
2755 case '{':
2756 ch = temp[cursor+1];
2757 if (ASCII.isDigit(ch)) {
2758 skip();
2759 int cmin = 0;
2760 do {
2761 cmin = cmin * 10 + (ch - '0');
2762 } while (ASCII.isDigit(ch = read()));
2763 int cmax = cmin;
2764 if (ch == ',') {
2765 ch = read();
2766 cmax = MAX_REPS;
2767 if (ch != '}') {
2768 cmax = 0;
2769 while (ASCII.isDigit(ch)) {
2770 cmax = cmax * 10 + (ch - '0');
2771 ch = read();
2772 }
2773 }
2774 }
2775 if (ch != '}')
2776 throw error("Unclosed counted closure");
2777 if (((cmin) | (cmax) | (cmax - cmin)) < 0)
2778 throw error("Illegal repetition range");
2779 Curly curly;
2780 ch = peek();
2781 if (ch == '?') {
2782 next();
2783 curly = new Curly(prev, cmin, cmax, LAZY);
2784 } else if (ch == '+') {
2785 next();
2786 curly = new Curly(prev, cmin, cmax, POSSESSIVE);
2787 } else {
2788 curly = new Curly(prev, cmin, cmax, GREEDY);
2789 }
2790 return curly;
2791 } else {
2792 throw error("Illegal repetition");
2793 }
2794 default:
2795 return prev;
2796 }
2797 }
2798
2799 /**
2800 * Utility method for parsing control escape sequences.
2801 */
2802 private int c() {
2803 if (cursor < patternLength) {
2804 return read() ^ 64;
2805 }
2806 throw error("Illegal control escape sequence");
2807 }
2808
2809 /**
2810 * Utility method for parsing octal escape sequences.
2811 */
2812 private int o() {
2813 int n = read();
2814 if (((n-'0')|('7'-n)) >= 0) {
2815 int m = read();
2816 if (((m-'0')|('7'-m)) >= 0) {
2817 int o = read();
2818 if ((((o-'0')|('7'-o)) >= 0) && (((n-'0')|('3'-n)) >= 0)) {
2819 return (n - '0') * 64 + (m - '0') * 8 + (o - '0');
2820 }
2821 unread();
2822 return (n - '0') * 8 + (m - '0');
2823 }
2824 unread();
2825 return (n - '0');
2826 }
2827 throw error("Illegal octal escape sequence");
2828 }
2829
2830 /**
2831 * Utility method for parsing hexadecimal escape sequences.
2832 */
2833 private int x() {
2834 int n = read();
2835 if (ASCII.isHexDigit(n)) {
2836 int m = read();
2837 if (ASCII.isHexDigit(m)) {
2838 return ASCII.toDigit(n) * 16 + ASCII.toDigit(m);
2839 }
2840 }
2841 throw error("Illegal hexadecimal escape sequence");
2842 }
2843
2844 /**
2845 * Utility method for parsing unicode escape sequences.
2846 */
2847 private int cursor() {
2848 return cursor;
2849 }
2850
2851 private void setcursor(int pos) {
2852 cursor = pos;
2853 }
2854
2855 private int uxxxx() {
2856 int n = 0;
2857 for (int i = 0; i < 4; i++) {
2858 int ch = read();
2859 if (!ASCII.isHexDigit(ch)) {
2860 throw error("Illegal Unicode escape sequence");
2861 }
2862 n = n * 16 + ASCII.toDigit(ch);
2863 }
2864 return n;
2865 }
2866
2867 private int u() {
2868 int n = uxxxx();
2869 if (Character.isHighSurrogate((char)n)) {
2870 int cur = cursor();
2871 if (read() == '\\' && read() == 'u') {
2872 int n2 = uxxxx();
2873 if (Character.isLowSurrogate((char)n2))
2874 return Character.toCodePoint((char)n, (char)n2);
2875 }
2876 setcursor(cur);
2877 }
2878 return n;
2879 }
2880
2881 //
2882 // Utility methods for code point support
2883 //
2884
2885 /**
2886 * Tests a surrogate value.
2887 */
2888 private static final boolean isSurrogate(int c) {
2889 return c >= Character.MIN_HIGH_SURROGATE && c <= Character.MAX_LOW_SURROGATE;
2890 }
2891
2892 private static final int countChars(CharSequence seq, int index,
2893 int lengthInCodePoints) {
2894 // optimization
2895 if (lengthInCodePoints == 1 && !Character.isHighSurrogate(seq.charAt(index))) {
2896 assert (index >= 0 && index < seq.length());
2897 return 1;
2898 }
2899 int length = seq.length();
2900 int x = index;
2901 if (lengthInCodePoints >= 0) {
2902 assert (index >= 0 && index < length);
2903 for (int i = 0; x < length && i < lengthInCodePoints; i++) {
2904 if (Character.isHighSurrogate(seq.charAt(x++))) {
2905 if (x < length && Character.isLowSurrogate(seq.charAt(x))) {
2906 x++;
2907 }
2908 }
2909 }
2910 return x - index;
2911 }
2912
2913 assert (index >= 0 && index <= length);
2914 if (index == 0) {
2915 return 0;
2916 }
2917 int len = -lengthInCodePoints;
2918 for (int i = 0; x > 0 && i < len; i++) {
2919 if (Character.isLowSurrogate(seq.charAt(--x))) {
2920 if (x > 0 && Character.isHighSurrogate(seq.charAt(x-1))) {
2921 x--;
2922 }
2923 }
2924 }
2925 return index - x;
2926 }
2927
2928 private static final int countCodePoints(CharSequence seq) {
2929 int length = seq.length();
2930 int n = 0;
2931 for (int i = 0; i < length; ) {
2932 n++;
2933 if (Character.isHighSurrogate(seq.charAt(i++))) {
2934 if (i < length && Character.isLowSurrogate(seq.charAt(i))) {
2935 i++;
2936 }
2937 }
2938 }
2939 return n;
2940 }
2941
2942 /**
2943 * Creates a bit vector for matching Latin-1 values. A normal BitClass
2944 * never matches values above Latin-1, and a complemented BitClass always
2945 * matches values above Latin-1.
2946 */
2947 private static final class BitClass extends BmpCharProperty {
2948 final boolean[] bits;
2949 BitClass() { bits = new boolean[256]; }
2950 private BitClass(boolean[] bits) { this.bits = bits; }
2951 BitClass add(int c, int flags) {
2952 assert c >= 0 && c <= 255;
2953 if ((flags & CASE_INSENSITIVE) != 0) {
2954 if (ASCII.isAscii(c)) {
2955 bits[ASCII.toUpper(c)] = true;
2956 bits[ASCII.toLower(c)] = true;
2957 } else if ((flags & UNICODE_CASE) != 0) {
2958 bits[Character.toLowerCase(c)] = true;
2959 bits[Character.toUpperCase(c)] = true;
2960 }
2961 }
2962 bits[c] = true;
2963 return this;
2964 }
2965 boolean isSatisfiedBy(int ch) {
2966 return ch < 256 && bits[ch];
2967 }
2968 }
2969
2970 /**
2971 * Returns a suitably optimized, single character matcher.
2972 */
2973 private CharProperty newSingle(final int ch) {
2974 if (has(CASE_INSENSITIVE)) {
2975 int lower, upper;
2976 if (has(UNICODE_CASE)) {
2977 upper = Character.toUpperCase(ch);
2978 lower = Character.toLowerCase(upper);
2979 if (upper != lower)
2980 return new SingleU(lower);
2981 } else if (ASCII.isAscii(ch)) {
2982 lower = ASCII.toLower(ch);
2983 upper = ASCII.toUpper(ch);
2984 if (lower != upper)
2985 return new SingleI(lower, upper);
2986 }
2987 }
2988 if (isSupplementary(ch))
2989 return new SingleS(ch); // Match a given Unicode character
2990 return new Single(ch); // Match a given BMP character
2991 }
2992
2993 /**
2994 * Utility method for creating a string slice matcher.
2995 */
2996 private Node newSlice(int[] buf, int count, boolean hasSupplementary) {
2997 int[] tmp = new int[count];
2998 if (has(CASE_INSENSITIVE)) {
2999 if (has(UNICODE_CASE)) {
3000 for (int i = 0; i < count; i++) {
3001 tmp[i] = Character.toLowerCase(
3002 Character.toUpperCase(buf[i]));
3003 }
3004 return hasSupplementary? new SliceUS(tmp) : new SliceU(tmp);
3005 }
3006 for (int i = 0; i < count; i++) {
3007 tmp[i] = ASCII.toLower(buf[i]);
3008 }
3009 return hasSupplementary? new SliceIS(tmp) : new SliceI(tmp);
3010 }
3011 for (int i = 0; i < count; i++) {
3012 tmp[i] = buf[i];
3013 }
3014 return hasSupplementary ? new SliceS(tmp) : new Slice(tmp);
3015 }
3016
3017 /**
3018 * The following classes are the building components of the object
3019 * tree that represents a compiled regular expression. The object tree
3020 * is made of individual elements that handle constructs in the Pattern.
3021 * Each type of object knows how to match its equivalent construct with
3022 * the match() method.
3023 */
3024
3025 /**
3026 * Base class for all node classes. Subclasses should override the match()
3027 * method as appropriate. This class is an accepting node, so its match()
3028 * always returns true.
3029 */
3030 static class Node extends Object {
3031 Node next;
3032 Node() {
3033 next = Pattern.accept;
3034 }
3035 /**
3036 * This method implements the classic accept node.
3037 */
3038 boolean match(Matcher matcher, int i, CharSequence seq) {
3039 matcher.last = i;
3040 matcher.groups[0] = matcher.first;
3041 matcher.groups[1] = matcher.last;
3042 return true;
3043 }
3044 /**
3045 * This method is good for all zero length assertions.
3046 */
3047 boolean study(TreeInfo info) {
3048 if (next != null) {
3049 return next.study(info);
3050 } else {
3051 return info.deterministic;
3052 }
3053 }
3054 }
3055
3056 static class LastNode extends Node {
3057 /**
3058 * This method implements the classic accept node with
3059 * the addition of a check to see if the match occurred
3060 * using all of the input.
3061 */
3062 boolean match(Matcher matcher, int i, CharSequence seq) {
3063 if (matcher.acceptMode == Matcher.ENDANCHOR && i != matcher.to)
3064 return false;
3065 matcher.last = i;
3066 matcher.groups[0] = matcher.first;
3067 matcher.groups[1] = matcher.last;
3068 return true;
3069 }
3070 }
3071
3072 /**
3073 * Used for REs that can start anywhere within the input string.
3074 * This basically tries to match repeatedly at each spot in the
3075 * input string, moving forward after each try. An anchored search
3076 * or a BnM will bypass this node completely.
3077 */
3078 static class Start extends Node {
3079 int minLength;
3080 Start(Node node) {
3081 this.next = node;
3082 TreeInfo info = new TreeInfo();
3083 next.study(info);
3084 minLength = info.minLength;
3085 }
3086 boolean match(Matcher matcher, int i, CharSequence seq) {
3087 if (i > matcher.to - minLength) {
3088 matcher.hitEnd = true;
3089 return false;
3090 }
3091 boolean ret = false;
3092 int guard = matcher.to - minLength;
3093 for (; i <= guard; i++) {
3094 if (ret = next.match(matcher, i, seq))
3095 break;
3096 if (i == guard)
3097 matcher.hitEnd = true;
3098 }
3099 if (ret) {
3100 matcher.first = i;
3101 matcher.groups[0] = matcher.first;
3102 matcher.groups[1] = matcher.last;
3103 }
3104 return ret;
3105 }
3106 boolean study(TreeInfo info) {
3107 next.study(info);
3108 info.maxValid = false;
3109 info.deterministic = false;
3110 return false;
3111 }
3112 }
3113
3114 /*
3115 * StartS supports supplementary characters, including unpaired surrogates.
3116 */
3117 static final class StartS extends Start {
3118 StartS(Node node) {
3119 super(node);
3120 }
3121 boolean match(Matcher matcher, int i, CharSequence seq) {
3122 if (i > matcher.to - minLength) {
3123 matcher.hitEnd = true;
3124 return false;
3125 }
3126 boolean ret = false;
3127 int guard = matcher.to - minLength;
3128 while (i <= guard) {
3129 if ((ret = next.match(matcher, i, seq)) || i == guard)
3130 break;
3131 // Optimization to move to the next character. This is
3132 // faster than countChars(seq, i, 1).
3133 if (Character.isHighSurrogate(seq.charAt(i++))) {
3134 if (i < seq.length() && Character.isLowSurrogate(seq.charAt(i))) {
3135 i++;
3136 }
3137 }
3138 if (i == guard)
3139 matcher.hitEnd = true;
3140 }
3141 if (ret) {
3142 matcher.first = i;
3143 matcher.groups[0] = matcher.first;
3144 matcher.groups[1] = matcher.last;
3145 }
3146 return ret;
3147 }
3148 }
3149
3150 /**
3151 * Node to anchor at the beginning of input. This object implements the
3152 * match for a \A sequence, and the caret anchor will use this if not in
3153 * multiline mode.
3154 */
3155 static final class Begin extends Node {
3156 boolean match(Matcher matcher, int i, CharSequence seq) {
3157 int fromIndex = (matcher.anchoringBounds) ?
3158 matcher.from : 0;
3159 if (i == fromIndex && next.match(matcher, i, seq)) {
3160 matcher.first = i;
3161 matcher.groups[0] = i;
3162 matcher.groups[1] = matcher.last;
3163 return true;
3164 } else {
3165 return false;
3166 }
3167 }
3168 }
3169
3170 /**
3171 * Node to anchor at the end of input. This is the absolute end, so this
3172 * should not match at the last newline before the end as $ will.
3173 */
3174 static final class End extends Node {
3175 boolean match(Matcher matcher, int i, CharSequence seq) {
3176 int endIndex = (matcher.anchoringBounds) ?
3177 matcher.to : matcher.getTextLength();
3178 if (i == endIndex) {
3179 matcher.hitEnd = true;
3180 return next.match(matcher, i, seq);
3181 }
3182 return false;
3183 }
3184 }
3185
3186 /**
3187 * Node to anchor at the beginning of a line. This is essentially the
3188 * object to match for the multiline ^.
3189 */
3190 static final class Caret extends Node {
3191 boolean match(Matcher matcher, int i, CharSequence seq) {
3192 int startIndex = matcher.from;
3193 int endIndex = matcher.to;
3194 if (!matcher.anchoringBounds) {
3195 startIndex = 0;
3196 endIndex = matcher.getTextLength();
3197 }
3198 // Perl does not match ^ at end of input even after newline
3199 if (i == endIndex) {
3200 matcher.hitEnd = true;
3201 return false;
3202 }
3203 if (i > startIndex) {
3204 char ch = seq.charAt(i-1);
3205 if (ch != '\n' && ch != '\r'
3206 && (ch|1) != '\u2029'
3207 && ch != '\u0085' ) {
3208 return false;
3209 }
3210 // Should treat /r/n as one newline
3211 if (ch == '\r' && seq.charAt(i) == '\n')
3212 return false;
3213 }
3214 return next.match(matcher, i, seq);
3215 }
3216 }
3217
3218 /**
3219 * Node to anchor at the beginning of a line when in unixdot mode.
3220 */
3221 static final class UnixCaret extends Node {
3222 boolean match(Matcher matcher, int i, CharSequence seq) {
3223 int startIndex = matcher.from;
3224 int endIndex = matcher.to;
3225 if (!matcher.anchoringBounds) {
3226 startIndex = 0;
3227 endIndex = matcher.getTextLength();
3228 }
3229 // Perl does not match ^ at end of input even after newline
3230 if (i == endIndex) {
3231 matcher.hitEnd = true;
3232 return false;
3233 }
3234 if (i > startIndex) {
3235 char ch = seq.charAt(i-1);
3236 if (ch != '\n') {
3237 return false;
3238 }
3239 }
3240 return next.match(matcher, i, seq);
3241 }
3242 }
3243
3244 /**
3245 * Node to match the location where the last match ended.
3246 * This is used for the \G construct.
3247 */
3248 static final class LastMatch extends Node {
3249 boolean match(Matcher matcher, int i, CharSequence seq) {
3250 if (i != matcher.oldLast)
3251 return false;
3252 return next.match(matcher, i, seq);
3253 }
3254 }
3255
3256 /**
3257 * Node to anchor at the end of a line or the end of input based on the
3258 * multiline mode.
3259 *
3260 * When not in multiline mode, the $ can only match at the very end
3261 * of the input, unless the input ends in a line terminator in which
3262 * it matches right before the last line terminator.
3263 *
3264 * Note that \r\n is considered an atomic line terminator.
3265 *
3266 * Like ^ the $ operator matches at a position, it does not match the
3267 * line terminators themselves.
3268 */
3269 static final class Dollar extends Node {
3270 boolean multiline;
3271 Dollar(boolean mul) {
3272 multiline = mul;
3273 }
3274 boolean match(Matcher matcher, int i, CharSequence seq) {
3275 int endIndex = (matcher.anchoringBounds) ?
3276 matcher.to : matcher.getTextLength();
3277 if (!multiline) {
3278 if (i < endIndex - 2)
3279 return false;
3280 if (i == endIndex - 2) {
3281 char ch = seq.charAt(i);
3282 if (ch != '\r')
3283 return false;
3284 ch = seq.charAt(i + 1);
3285 if (ch != '\n')
3286 return false;
3287 }
3288 }
3289 // Matches before any line terminator; also matches at the
3290 // end of input
3291 // Before line terminator:
3292 // If multiline, we match here no matter what
3293 // If not multiline, fall through so that the end
3294 // is marked as hit; this must be a /r/n or a /n
3295 // at the very end so the end was hit; more input
3296 // could make this not match here
3297 if (i < endIndex) {
3298 char ch = seq.charAt(i);
3299 if (ch == '\n') {
3300 // No match between \r\n
3301 if (i > 0 && seq.charAt(i-1) == '\r')
3302 return false;
3303 if (multiline)
3304 return next.match(matcher, i, seq);
3305 } else if (ch == '\r' || ch == '\u0085' ||
3306 (ch|1) == '\u2029') {
3307 if (multiline)
3308 return next.match(matcher, i, seq);
3309 } else { // No line terminator, no match
3310 return false;
3311 }
3312 }
3313 // Matched at current end so hit end
3314 matcher.hitEnd = true;
3315 // If a $ matches because of end of input, then more input
3316 // could cause it to fail!
3317 matcher.requireEnd = true;
3318 return next.match(matcher, i, seq);
3319 }
3320 boolean study(TreeInfo info) {
3321 next.study(info);
3322 return info.deterministic;
3323 }
3324 }
3325
3326 /**
3327 * Node to anchor at the end of a line or the end of input based on the
3328 * multiline mode when in unix lines mode.
3329 */
3330 static final class UnixDollar extends Node {
3331 boolean multiline;
3332 UnixDollar(boolean mul) {
3333 multiline = mul;
3334 }
3335 boolean match(Matcher matcher, int i, CharSequence seq) {
3336 int endIndex = (matcher.anchoringBounds) ?
3337 matcher.to : matcher.getTextLength();
3338 if (i < endIndex) {
3339 char ch = seq.charAt(i);
3340 if (ch == '\n') {
3341 // If not multiline, then only possible to
3342 // match at very end or one before end
3343 if (multiline == false && i != endIndex - 1)
3344 return false;
3345 // If multiline return next.match without setting
3346 // matcher.hitEnd
3347 if (multiline)
3348 return next.match(matcher, i, seq);
3349 } else {
3350 return false;
3351 }
3352 }
3353 // Matching because at the end or 1 before the end;
3354 // more input could change this so set hitEnd
3355 matcher.hitEnd = true;
3356 // If a $ matches because of end of input, then more input
3357 // could cause it to fail!
3358 matcher.requireEnd = true;
3359 return next.match(matcher, i, seq);
3360 }
3361 boolean study(TreeInfo info) {
3362 next.study(info);
3363 return info.deterministic;
3364 }
3365 }
3366
3367 /**
3368 * Abstract node class to match one character satisfying some
3369 * boolean property.
3370 */
3371 private static abstract class CharProperty extends Node {
3372 abstract boolean isSatisfiedBy(int ch);
3373 CharProperty complement() {
3374 return new CharProperty() {
3375 boolean isSatisfiedBy(int ch) {
3376 return ! CharProperty.this.isSatisfiedBy(ch);}};
3377 }
3378 CharProperty maybeComplement(boolean complement) {
3379 return complement ? complement() : this;
3380 }
3381 boolean match(Matcher matcher, int i, CharSequence seq) {
3382 if (i < matcher.to) {
3383 int ch = Character.codePointAt(seq, i);
3384 return isSatisfiedBy(ch)
3385 && next.match(matcher, i+Character.charCount(ch), seq);
3386 } else {
3387 matcher.hitEnd = true;
3388 return false;
3389 }
3390 }
3391 boolean study(TreeInfo info) {
3392 info.minLength++;
3393 info.maxLength++;
3394 return next.study(info);
3395 }
3396 }
3397
3398 /**
3399 * Optimized version of CharProperty that works only for
3400 * properties never satisfied by Supplementary characters.
3401 */
3402 private static abstract class BmpCharProperty extends CharProperty {
3403 boolean match(Matcher matcher, int i, CharSequence seq) {
3404 if (i < matcher.to) {
3405 return isSatisfiedBy(seq.charAt(i))
3406 && next.match(matcher, i+1, seq);
3407 } else {
3408 matcher.hitEnd = true;
3409 return false;
3410 }
3411 }
3412 }
3413
3414 /**
3415 * Node class that matches a Supplementary Unicode character
3416 */
3417 static final class SingleS extends CharProperty {
3418 final int c;
3419 SingleS(int c) { this.c = c; }
3420 boolean isSatisfiedBy(int ch) {
3421 return ch == c;
3422 }
3423 }
3424
3425 /**
3426 * Optimization -- matches a given BMP character
3427 */
3428 static final class Single extends BmpCharProperty {
3429 final int c;
3430 Single(int c) { this.c = c; }
3431 boolean isSatisfiedBy(int ch) {
3432 return ch == c;
3433 }
3434 }
3435
3436 /**
3437 * Case insensitive matches a given BMP character
3438 */
3439 static final class SingleI extends BmpCharProperty {
3440 final int lower;
3441 final int upper;
3442 SingleI(int lower, int upper) {
3443 this.lower = lower;
3444 this.upper = upper;
3445 }
3446 boolean isSatisfiedBy(int ch) {
3447 return ch == lower || ch == upper;
3448 }
3449 }
3450
3451 /**
3452 * Unicode case insensitive matches a given Unicode character
3453 */
3454 static final class SingleU extends CharProperty {
3455 final int lower;
3456 SingleU(int lower) {
3457 this.lower = lower;
3458 }
3459 boolean isSatisfiedBy(int ch) {
3460 return lower == ch ||
3461 lower == Character.toLowerCase(Character.toUpperCase(ch));
3462 }
3463 }
3464
3465 /**
3466 * Node class that matches a Unicode category.
3467 */
3468 static final class Category extends CharProperty {
3469 final int typeMask;
3470 Category(int typeMask) { this.typeMask = typeMask; }
3471 boolean isSatisfiedBy(int ch) {
3472 return (typeMask & (1 << Character.getType(ch))) != 0;
3473 }
3474 }
3475
3476 /**
3477 * Node class that matches a POSIX type.
3478 */
3479 static final class Ctype extends BmpCharProperty {
3480 final int ctype;
3481 Ctype(int ctype) { this.ctype = ctype; }
3482 boolean isSatisfiedBy(int ch) {
3483 return ch < 128 && ASCII.isType(ch, ctype);
3484 }
3485 }
3486
3487 /**
3488 * Base class for all Slice nodes
3489 */
3490 static class SliceNode extends Node {
3491 int[] buffer;
3492 SliceNode(int[] buf) {
3493 buffer = buf;
3494 }
3495 boolean study(TreeInfo info) {
3496 info.minLength += buffer.length;
3497 info.maxLength += buffer.length;
3498 return next.study(info);
3499 }
3500 }
3501
3502 /**
3503 * Node class for a case sensitive/BMP-only sequence of literal
3504 * characters.
3505 */
3506 static final class Slice extends SliceNode {
3507 Slice(int[] buf) {
3508 super(buf);
3509 }
3510 boolean match(Matcher matcher, int i, CharSequence seq) {
3511 int[] buf = buffer;
3512 int len = buf.length;
3513 for (int j=0; j<len; j++) {
3514 if ((i+j) >= matcher.to) {
3515 matcher.hitEnd = true;
3516 return false;
3517 }
3518 if (buf[j] != seq.charAt(i+j))
3519 return false;
3520 }
3521 return next.match(matcher, i+len, seq);
3522 }
3523 }
3524
3525 /**
3526 * Node class for a case_insensitive/BMP-only sequence of literal
3527 * characters.
3528 */
3529 static class SliceI extends SliceNode {
3530 SliceI(int[] buf) {
3531 super(buf);
3532 }
3533 boolean match(Matcher matcher, int i, CharSequence seq) {
3534 int[] buf = buffer;
3535 int len = buf.length;
3536 for (int j=0; j<len; j++) {
3537 if ((i+j) >= matcher.to) {
3538 matcher.hitEnd = true;
3539 return false;
3540 }
3541 int c = seq.charAt(i+j);
3542 if (buf[j] != c &&
3543 buf[j] != ASCII.toLower(c))
3544 return false;
3545 }
3546 return next.match(matcher, i+len, seq);
3547 }
3548 }
3549
3550 /**
3551 * Node class for a unicode_case_insensitive/BMP-only sequence of
3552 * literal characters. Uses unicode case folding.
3553 */
3554 static final class SliceU extends SliceNode {
3555 SliceU(int[] buf) {
3556 super(buf);
3557 }
3558 boolean match(Matcher matcher, int i, CharSequence seq) {
3559 int[] buf = buffer;
3560 int len = buf.length;
3561 for (int j=0; j<len; j++) {
3562 if ((i+j) >= matcher.to) {
3563 matcher.hitEnd = true;
3564 return false;
3565 }
3566 int c = seq.charAt(i+j);
3567 if (buf[j] != c &&
3568 buf[j] != Character.toLowerCase(Character.toUpperCase(c)))
3569 return false;
3570 }
3571 return next.match(matcher, i+len, seq);
3572 }
3573 }
3574
3575 /**
3576 * Node class for a case sensitive sequence of literal characters
3577 * including supplementary characters.
3578 */
3579 static final class SliceS extends SliceNode {
3580 SliceS(int[] buf) {
3581 super(buf);
3582 }
3583 boolean match(Matcher matcher, int i, CharSequence seq) {
3584 int[] buf = buffer;
3585 int x = i;
3586 for (int j = 0; j < buf.length; j++) {
3587 if (x >= matcher.to) {
3588 matcher.hitEnd = true;
3589 return false;
3590 }
3591 int c = Character.codePointAt(seq, x);
3592 if (buf[j] != c)
3593 return false;
3594 x += Character.charCount(c);
3595 if (x > matcher.to) {
3596 matcher.hitEnd = true;
3597 return false;
3598 }
3599 }
3600 return next.match(matcher, x, seq);
3601 }
3602 }
3603
3604 /**
3605 * Node class for a case insensitive sequence of literal characters
3606 * including supplementary characters.
3607 */
3608 static class SliceIS extends SliceNode {
3609 SliceIS(int[] buf) {
3610 super(buf);
3611 }
3612 int toLower(int c) {
3613 return ASCII.toLower(c);
3614 }
3615 boolean match(Matcher matcher, int i, CharSequence seq) {
3616 int[] buf = buffer;
3617 int x = i;
3618 for (int j = 0; j < buf.length; j++) {
3619 if (x >= matcher.to) {
3620 matcher.hitEnd = true;
3621 return false;
3622 }
3623 int c = Character.codePointAt(seq, x);
3624 if (buf[j] != c && buf[j] != toLower(c))
3625 return false;
3626 x += Character.charCount(c);
3627 if (x > matcher.to) {
3628 matcher.hitEnd = true;
3629 return false;
3630 }
3631 }
3632 return next.match(matcher, x, seq);
3633 }
3634 }
3635
3636 /**
3637 * Node class for a case insensitive sequence of literal characters.
3638 * Uses unicode case folding.
3639 */
3640 static final class SliceUS extends SliceIS {
3641 SliceUS(int[] buf) {
3642 super(buf);
3643 }
3644 int toLower(int c) {
3645 return Character.toLowerCase(Character.toUpperCase(c));
3646 }
3647 }
3648
3649 private static boolean inRange(int lower, int ch, int upper) {
3650 return lower <= ch && ch <= upper;
3651 }
3652
3653 /**
3654 * Returns node for matching characters within an explicit value range.
3655 */
3656 private static CharProperty rangeFor(final int lower,
3657 final int upper) {
3658 return new CharProperty() {
3659 boolean isSatisfiedBy(int ch) {
3660 return inRange(lower, ch, upper);}};
3661 }
3662
3663 /**
3664 * Returns node for matching characters within an explicit value
3665 * range in a case insensitive manner.
3666 */
3667 private CharProperty caseInsensitiveRangeFor(final int lower,
3668 final int upper) {
3669 if (has(UNICODE_CASE))
3670 return new CharProperty() {
3671 boolean isSatisfiedBy(int ch) {
3672 if (inRange(lower, ch, upper))
3673 return true;
3674 int up = Character.toUpperCase(ch);
3675 return inRange(lower, up, upper) ||
3676 inRange(lower, Character.toLowerCase(up), upper);}};
3677 return new CharProperty() {
3678 boolean isSatisfiedBy(int ch) {
3679 return inRange(lower, ch, upper) ||
3680 ASCII.isAscii(ch) &&
3681 (inRange(lower, ASCII.toUpper(ch), upper) ||
3682 inRange(lower, ASCII.toLower(ch), upper));
3683 }};
3684 }
3685
3686 /**
3687 * Implements the Unicode category ALL and the dot metacharacter when
3688 * in dotall mode.
3689 */
3690 static final class All extends CharProperty {
3691 boolean isSatisfiedBy(int ch) {
3692 return true;
3693 }
3694 }
3695
3696 /**
3697 * Node class for the dot metacharacter when dotall is not enabled.
3698 */
3699 static final class Dot extends CharProperty {
3700 boolean isSatisfiedBy(int ch) {
3701 return (ch != '\n' && ch != '\r'
3702 && (ch|1) != '\u2029'
3703 && ch != '\u0085');
3704 }
3705 }
3706
3707 /**
3708 * Node class for the dot metacharacter when dotall is not enabled
3709 * but UNIX_LINES is enabled.
3710 */
3711 static final class UnixDot extends CharProperty {
3712 boolean isSatisfiedBy(int ch) {
3713 return ch != '\n';
3714 }
3715 }
3716
3717 /**
3718 * The 0 or 1 quantifier. This one class implements all three types.
3719 */
3720 static final class Ques extends Node {
3721 Node atom;
3722 int type;
3723 Ques(Node node, int type) {
3724 this.atom = node;
3725 this.type = type;
3726 }
3727 boolean match(Matcher matcher, int i, CharSequence seq) {
3728 switch (type) {
3729 case GREEDY:
3730 return (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq))
3731 || next.match(matcher, i, seq);
3732 case LAZY:
3733 return next.match(matcher, i, seq)
3734 || (atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq));
3735 case POSSESSIVE:
3736 if (atom.match(matcher, i, seq)) i = matcher.last;
3737 return next.match(matcher, i, seq);
3738 default:
3739 return atom.match(matcher, i, seq) && next.match(matcher, matcher.last, seq);
3740 }
3741 }
3742 boolean study(TreeInfo info) {
3743 if (type != INDEPENDENT) {
3744 int minL = info.minLength;
3745 atom.study(info);
3746 info.minLength = minL;
3747 info.deterministic = false;
3748 return next.study(info);
3749 } else {
3750 atom.study(info);
3751 return next.study(info);
3752 }
3753 }
3754 }
3755
3756 /**
3757 * Handles the curly-brace style repetition with a specified minimum and
3758 * maximum occurrences. The * quantifier is handled as a special case.
3759 * This class handles the three types.
3760 */
3761 static final class Curly extends Node {
3762 Node atom;
3763 int type;
3764 int cmin;
3765 int cmax;
3766
3767 Curly(Node node, int cmin, int cmax, int type) {
3768 this.atom = node;
3769 this.type = type;
3770 this.cmin = cmin;
3771 this.cmax = cmax;
3772 }
3773 boolean match(Matcher matcher, int i, CharSequence seq) {
3774 int j;
3775 for (j = 0; j < cmin; j++) {
3776 if (atom.match(matcher, i, seq)) {
3777 i = matcher.last;
3778 continue;
3779 }
3780 return false;
3781 }
3782 if (type == GREEDY)
3783 return match0(matcher, i, j, seq);
3784 else if (type == LAZY)
3785 return match1(matcher, i, j, seq);
3786 else
3787 return match2(matcher, i, j, seq);
3788 }
3789 // Greedy match.
3790 // i is the index to start matching at
3791 // j is the number of atoms that have matched
3792 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
3793 if (j >= cmax) {
3794 // We have matched the maximum... continue with the rest of
3795 // the regular expression
3796 return next.match(matcher, i, seq);
3797 }
3798 int backLimit = j;
3799 while (atom.match(matcher, i, seq)) {
3800 // k is the length of this match
3801 int k = matcher.last - i;
3802 if (k == 0) // Zero length match
3803 break;
3804 // Move up index and number matched
3805 i = matcher.last;
3806 j++;
3807 // We are greedy so match as many as we can
3808 while (j < cmax) {
3809 if (!atom.match(matcher, i, seq))
3810 break;
3811 if (i + k != matcher.last) {
3812 if (match0(matcher, matcher.last, j+1, seq))
3813 return true;
3814 break;
3815 }
3816 i += k;
3817 j++;
3818 }
3819 // Handle backing off if match fails
3820 while (j >= backLimit) {
3821 if (next.match(matcher, i, seq))
3822 return true;
3823 i -= k;
3824 j--;
3825 }
3826 return false;
3827 }
3828 return next.match(matcher, i, seq);
3829 }
3830 // Reluctant match. At this point, the minimum has been satisfied.
3831 // i is the index to start matching at
3832 // j is the number of atoms that have matched
3833 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
3834 for (;;) {
3835 // Try finishing match without consuming any more
3836 if (next.match(matcher, i, seq))
3837 return true;
3838 // At the maximum, no match found
3839 if (j >= cmax)
3840 return false;
3841 // Okay, must try one more atom
3842 if (!atom.match(matcher, i, seq))
3843 return false;
3844 // If we haven't moved forward then must break out
3845 if (i == matcher.last)
3846 return false;
3847 // Move up index and number matched
3848 i = matcher.last;
3849 j++;
3850 }
3851 }
3852 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
3853 for (; j < cmax; j++) {
3854 if (!atom.match(matcher, i, seq))
3855 break;
3856 if (i == matcher.last)
3857 break;
3858 i = matcher.last;
3859 }
3860 return next.match(matcher, i, seq);
3861 }
3862 boolean study(TreeInfo info) {
3863 // Save original info
3864 int minL = info.minLength;
3865 int maxL = info.maxLength;
3866 boolean maxV = info.maxValid;
3867 boolean detm = info.deterministic;
3868 info.reset();
3869
3870 atom.study(info);
3871
3872 int temp = info.minLength * cmin + minL;
3873 if (temp < minL) {
3874 temp = 0xFFFFFFF; // arbitrary large number
3875 }
3876 info.minLength = temp;
3877
3878 if (maxV & info.maxValid) {
3879 temp = info.maxLength * cmax + maxL;
3880 info.maxLength = temp;
3881 if (temp < maxL) {
3882 info.maxValid = false;
3883 }
3884 } else {
3885 info.maxValid = false;
3886 }
3887
3888 if (info.deterministic && cmin == cmax)
3889 info.deterministic = detm;
3890 else
3891 info.deterministic = false;
3892
3893 return next.study(info);
3894 }
3895 }
3896
3897 /**
3898 * Handles the curly-brace style repetition with a specified minimum and
3899 * maximum occurrences in deterministic cases. This is an iterative
3900 * optimization over the Prolog and Loop system which would handle this
3901 * in a recursive way. The * quantifier is handled as a special case.
3902 * If capture is true then this class saves group settings and ensures
3903 * that groups are unset when backing off of a group match.
3904 */
3905 static final class GroupCurly extends Node {
3906 Node atom;
3907 int type;
3908 int cmin;
3909 int cmax;
3910 int localIndex;
3911 int groupIndex;
3912 boolean capture;
3913
3914 GroupCurly(Node node, int cmin, int cmax, int type, int local,
3915 int group, boolean capture) {
3916 this.atom = node;
3917 this.type = type;
3918 this.cmin = cmin;
3919 this.cmax = cmax;
3920 this.localIndex = local;
3921 this.groupIndex = group;
3922 this.capture = capture;
3923 }
3924 boolean match(Matcher matcher, int i, CharSequence seq) {
3925 int[] groups = matcher.groups;
3926 int[] locals = matcher.locals;
3927 int save0 = locals[localIndex];
3928 int save1 = 0;
3929 int save2 = 0;
3930
3931 if (capture) {
3932 save1 = groups[groupIndex];
3933 save2 = groups[groupIndex+1];
3934 }
3935
3936 // Notify GroupTail there is no need to setup group info
3937 // because it will be set here
3938 locals[localIndex] = -1;
3939
3940 boolean ret = true;
3941 for (int j = 0; j < cmin; j++) {
3942 if (atom.match(matcher, i, seq)) {
3943 if (capture) {
3944 groups[groupIndex] = i;
3945 groups[groupIndex+1] = matcher.last;
3946 }
3947 i = matcher.last;
3948 } else {
3949 ret = false;
3950 break;
3951 }
3952 }
3953 if (ret) {
3954 if (type == GREEDY) {
3955 ret = match0(matcher, i, cmin, seq);
3956 } else if (type == LAZY) {
3957 ret = match1(matcher, i, cmin, seq);
3958 } else {
3959 ret = match2(matcher, i, cmin, seq);
3960 }
3961 }
3962 if (!ret) {
3963 locals[localIndex] = save0;
3964 if (capture) {
3965 groups[groupIndex] = save1;
3966 groups[groupIndex+1] = save2;
3967 }
3968 }
3969 return ret;
3970 }
3971 // Aggressive group match
3972 boolean match0(Matcher matcher, int i, int j, CharSequence seq) {
3973 int[] groups = matcher.groups;
3974 int save0 = 0;
3975 int save1 = 0;
3976 if (capture) {
3977 save0 = groups[groupIndex];
3978 save1 = groups[groupIndex+1];
3979 }
3980 for (;;) {
3981 if (j >= cmax)
3982 break;
3983 if (!atom.match(matcher, i, seq))
3984 break;
3985 int k = matcher.last - i;
3986 if (k <= 0) {
3987 if (capture) {
3988 groups[groupIndex] = i;
3989 groups[groupIndex+1] = i + k;
3990 }
3991 i = i + k;
3992 break;
3993 }
3994 for (;;) {
3995 if (capture) {
3996 groups[groupIndex] = i;
3997 groups[groupIndex+1] = i + k;
3998 }
3999 i = i + k;
4000 if (++j >= cmax)
4001 break;
4002 if (!atom.match(matcher, i, seq))
4003 break;
4004 if (i + k != matcher.last) {
4005 if (match0(matcher, i, j, seq))
4006 return true;
4007 break;
4008 }
4009 }
4010 while (j > cmin) {
4011 if (next.match(matcher, i, seq)) {
4012 if (capture) {
4013 groups[groupIndex+1] = i;
4014 groups[groupIndex] = i - k;
4015 }
4016 i = i - k;
4017 return true;
4018 }
4019 // backing off
4020 if (capture) {
4021 groups[groupIndex+1] = i;
4022 groups[groupIndex] = i - k;
4023 }
4024 i = i - k;
4025 j--;
4026 }
4027 break;
4028 }
4029 if (capture) {
4030 groups[groupIndex] = save0;
4031 groups[groupIndex+1] = save1;
4032 }
4033 return next.match(matcher, i, seq);
4034 }
4035 // Reluctant matching
4036 boolean match1(Matcher matcher, int i, int j, CharSequence seq) {
4037 for (;;) {
4038 if (next.match(matcher, i, seq))
4039 return true;
4040 if (j >= cmax)
4041 return false;
4042 if (!atom.match(matcher, i, seq))
4043 return false;
4044 if (i == matcher.last)
4045 return false;
4046 if (capture) {
4047 matcher.groups[groupIndex] = i;
4048 matcher.groups[groupIndex+1] = matcher.last;
4049 }
4050 i = matcher.last;
4051 j++;
4052 }
4053 }
4054 // Possessive matching
4055 boolean match2(Matcher matcher, int i, int j, CharSequence seq) {
4056 for (; j < cmax; j++) {
4057 if (!atom.match(matcher, i, seq)) {
4058 break;
4059 }
4060 if (capture) {
4061 matcher.groups[groupIndex] = i;
4062 matcher.groups[groupIndex+1] = matcher.last;
4063 }
4064 if (i == matcher.last) {
4065 break;
4066 }
4067 i = matcher.last;
4068 }
4069 return next.match(matcher, i, seq);
4070 }
4071 boolean study(TreeInfo info) {
4072 // Save original info
4073 int minL = info.minLength;
4074 int maxL = info.maxLength;
4075 boolean maxV = info.maxValid;
4076 boolean detm = info.deterministic;
4077 info.reset();
4078
4079 atom.study(info);
4080
4081 int temp = info.minLength * cmin + minL;
4082 if (temp < minL) {
4083 temp = 0xFFFFFFF; // Arbitrary large number
4084 }
4085 info.minLength = temp;
4086
4087 if (maxV & info.maxValid) {
4088 temp = info.maxLength * cmax + maxL;
4089 info.maxLength = temp;
4090 if (temp < maxL) {
4091 info.maxValid = false;
4092 }
4093 } else {
4094 info.maxValid = false;
4095 }
4096
4097 if (info.deterministic && cmin == cmax) {
4098 info.deterministic = detm;
4099 } else {
4100 info.deterministic = false;
4101 }
4102
4103 return next.study(info);
4104 }
4105 }
4106
4107 /**
4108 * A Guard node at the end of each atom node in a Branch. It
4109 * serves the purpose of chaining the "match" operation to
4110 * "next" but not the "study", so we can collect the TreeInfo
4111 * of each atom node without including the TreeInfo of the
4112 * "next".
4113 */
4114 static final class BranchConn extends Node {
4115 BranchConn() {};
4116 boolean match(Matcher matcher, int i, CharSequence seq) {
4117 return next.match(matcher, i, seq);
4118 }
4119 boolean study(TreeInfo info) {
4120 return info.deterministic;
4121 }
4122 }
4123
4124 /**
4125 * Handles the branching of alternations. Note this is also used for
4126 * the ? quantifier to branch between the case where it matches once
4127 * and where it does not occur.
4128 */
4129 static final class Branch extends Node {
4130 Node[] atoms = new Node[2];
4131 int size = 2;
4132 Node conn;
4133 Branch(Node first, Node second, Node branchConn) {
4134 conn = branchConn;
4135 atoms[0] = first;
4136 atoms[1] = second;
4137 }
4138
4139 void add(Node node) {
4140 if (size >= atoms.length) {
4141 Node[] tmp = new Node[atoms.length*2];
4142 System.arraycopy(atoms, 0, tmp, 0, atoms.length);
4143 atoms = tmp;
4144 }
4145 atoms[size++] = node;
4146 }
4147
4148 boolean match(Matcher matcher, int i, CharSequence seq) {
4149 for (int n = 0; n < size; n++) {
4150 if (atoms[n] == null) {
4151 if (conn.next.match(matcher, i, seq))
4152 return true;
4153 } else if (atoms[n].match(matcher, i, seq)) {
4154 return true;
4155 }
4156 }
4157 return false;
4158 }
4159
4160 boolean study(TreeInfo info) {
4161 int minL = info.minLength;
4162 int maxL = info.maxLength;
4163 boolean maxV = info.maxValid;
4164
4165 int minL2 = Integer.MAX_VALUE; //arbitrary large enough num
4166 int maxL2 = -1;
4167 for (int n = 0; n < size; n++) {
4168 info.reset();
4169 if (atoms[n] != null)
4170 atoms[n].study(info);
4171 minL2 = Math.min(minL2, info.minLength);
4172 maxL2 = Math.max(maxL2, info.maxLength);
4173 maxV = (maxV & info.maxValid);
4174 }
4175
4176 minL += minL2;
4177 maxL += maxL2;
4178
4179 info.reset();
4180 conn.next.study(info);
4181
4182 info.minLength += minL;
4183 info.maxLength += maxL;
4184 info.maxValid &= maxV;
4185 info.deterministic = false;
4186 return false;
4187 }
4188 }
4189
4190 /**
4191 * The GroupHead saves the location where the group begins in the locals
4192 * and restores them when the match is done.
4193 *
4194 * The matchRef is used when a reference to this group is accessed later
4195 * in the expression. The locals will have a negative value in them to
4196 * indicate that we do not want to unset the group if the reference
4197 * doesn't match.
4198 */
4199 static final class GroupHead extends Node {
4200 int localIndex;
4201 GroupHead(int localCount) {
4202 localIndex = localCount;
4203 }
4204 boolean match(Matcher matcher, int i, CharSequence seq) {
4205 int save = matcher.locals[localIndex];
4206 matcher.locals[localIndex] = i;
4207 boolean ret = next.match(matcher, i, seq);
4208 matcher.locals[localIndex] = save;
4209 return ret;
4210 }
4211 boolean matchRef(Matcher matcher, int i, CharSequence seq) {
4212 int save = matcher.locals[localIndex];
4213 matcher.locals[localIndex] = ~i; // HACK
4214 boolean ret = next.match(matcher, i, seq);
4215 matcher.locals[localIndex] = save;
4216 return ret;
4217 }
4218 }
4219
4220 /**
4221 * Recursive reference to a group in the regular expression. It calls
4222 * matchRef because if the reference fails to match we would not unset
4223 * the group.
4224 */
4225 static final class GroupRef extends Node {
4226 GroupHead head;
4227 GroupRef(GroupHead head) {
4228 this.head = head;
4229 }
4230 boolean match(Matcher matcher, int i, CharSequence seq) {
4231 return head.matchRef(matcher, i, seq)
4232 && next.match(matcher, matcher.last, seq);
4233 }
4234 boolean study(TreeInfo info) {
4235 info.maxValid = false;
4236 info.deterministic = false;
4237 return next.study(info);
4238 }
4239 }
4240
4241 /**
4242 * The GroupTail handles the setting of group beginning and ending
4243 * locations when groups are successfully matched. It must also be able to
4244 * unset groups that have to be backed off of.
4245 *
4246 * The GroupTail node is also used when a previous group is referenced,
4247 * and in that case no group information needs to be set.
4248 */
4249 static final class GroupTail extends Node {
4250 int localIndex;
4251 int groupIndex;
4252 GroupTail(int localCount, int groupCount) {
4253 localIndex = localCount;
4254 groupIndex = groupCount + groupCount;
4255 }
4256 boolean match(Matcher matcher, int i, CharSequence seq) {
4257 int tmp = matcher.locals[localIndex];
4258 if (tmp >= 0) { // This is the normal group case.
4259 // Save the group so we can unset it if it
4260 // backs off of a match.
4261 int groupStart = matcher.groups[groupIndex];
4262 int groupEnd = matcher.groups[groupIndex+1];
4263
4264 matcher.groups[groupIndex] = tmp;
4265 matcher.groups[groupIndex+1] = i;
4266 if (next.match(matcher, i, seq)) {
4267 return true;
4268 }
4269 matcher.groups[groupIndex] = groupStart;
4270 matcher.groups[groupIndex+1] = groupEnd;
4271 return false;
4272 } else {
4273 // This is a group reference case. We don't need to save any
4274 // group info because it isn't really a group.
4275 matcher.last = i;
4276 return true;
4277 }
4278 }
4279 }
4280
4281 /**
4282 * This sets up a loop to handle a recursive quantifier structure.
4283 */
4284 static final class Prolog extends Node {
4285 Loop loop;
4286 Prolog(Loop loop) {
4287 this.loop = loop;
4288 }
4289 boolean match(Matcher matcher, int i, CharSequence seq) {
4290 return loop.matchInit(matcher, i, seq);
4291 }
4292 boolean study(TreeInfo info) {
4293 return loop.study(info);
4294 }
4295 }
4296
4297 /**
4298 * Handles the repetition count for a greedy Curly. The matchInit
4299 * is called from the Prolog to save the index of where the group
4300 * beginning is stored. A zero length group check occurs in the
4301 * normal match but is skipped in the matchInit.
4302 */
4303 static class Loop extends Node {
4304 Node body;
4305 int countIndex; // local count index in matcher locals
4306 int beginIndex; // group beginning index
4307 int cmin, cmax;
4308 Loop(int countIndex, int beginIndex) {
4309 this.countIndex = countIndex;
4310 this.beginIndex = beginIndex;
4311 }
4312 boolean match(Matcher matcher, int i, CharSequence seq) {
4313 // Avoid infinite loop in zero-length case.
4314 if (i > matcher.locals[beginIndex]) {
4315 int count = matcher.locals[countIndex];
4316
4317 // This block is for before we reach the minimum
4318 // iterations required for the loop to match
4319 if (count < cmin) {
4320 matcher.locals[countIndex] = count + 1;
4321 boolean b = body.match(matcher, i, seq);
4322 // If match failed we must backtrack, so
4323 // the loop count should NOT be incremented
4324 if (!b)
4325 matcher.locals[countIndex] = count;
4326 // Return success or failure since we are under
4327 // minimum
4328 return b;
4329 }
4330 // This block is for after we have the minimum
4331 // iterations required for the loop to match
4332 if (count < cmax) {
4333 matcher.locals[countIndex] = count + 1;
4334 boolean b = body.match(matcher, i, seq);
4335 // If match failed we must backtrack, so
4336 // the loop count should NOT be incremented
4337 if (!b)
4338 matcher.locals[countIndex] = count;
4339 else
4340 return true;
4341 }
4342 }
4343 return next.match(matcher, i, seq);
4344 }
4345 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4346 int save = matcher.locals[countIndex];
4347 boolean ret = false;
4348 if (0 < cmin) {
4349 matcher.locals[countIndex] = 1;
4350 ret = body.match(matcher, i, seq);
4351 } else if (0 < cmax) {
4352 matcher.locals[countIndex] = 1;
4353 ret = body.match(matcher, i, seq);
4354 if (ret == false)
4355 ret = next.match(matcher, i, seq);
4356 } else {
4357 ret = next.match(matcher, i, seq);
4358 }
4359 matcher.locals[countIndex] = save;
4360 return ret;
4361 }
4362 boolean study(TreeInfo info) {
4363 info.maxValid = false;
4364 info.deterministic = false;
4365 return false;
4366 }
4367 }
4368
4369 /**
4370 * Handles the repetition count for a reluctant Curly. The matchInit
4371 * is called from the Prolog to save the index of where the group
4372 * beginning is stored. A zero length group check occurs in the
4373 * normal match but is skipped in the matchInit.
4374 */
4375 static final class LazyLoop extends Loop {
4376 LazyLoop(int countIndex, int beginIndex) {
4377 super(countIndex, beginIndex);
4378 }
4379 boolean match(Matcher matcher, int i, CharSequence seq) {
4380 // Check for zero length group
4381 if (i > matcher.locals[beginIndex]) {
4382 int count = matcher.locals[countIndex];
4383 if (count < cmin) {
4384 matcher.locals[countIndex] = count + 1;
4385 boolean result = body.match(matcher, i, seq);
4386 // If match failed we must backtrack, so
4387 // the loop count should NOT be incremented
4388 if (!result)
4389 matcher.locals[countIndex] = count;
4390 return result;
4391 }
4392 if (next.match(matcher, i, seq))
4393 return true;
4394 if (count < cmax) {
4395 matcher.locals[countIndex] = count + 1;
4396 boolean result = body.match(matcher, i, seq);
4397 // If match failed we must backtrack, so
4398 // the loop count should NOT be incremented
4399 if (!result)
4400 matcher.locals[countIndex] = count;
4401 return result;
4402 }
4403 return false;
4404 }
4405 return next.match(matcher, i, seq);
4406 }
4407 boolean matchInit(Matcher matcher, int i, CharSequence seq) {
4408 int save = matcher.locals[countIndex];
4409 boolean ret = false;
4410 if (0 < cmin) {
4411 matcher.locals[countIndex] = 1;
4412 ret = body.match(matcher, i, seq);
4413 } else if (next.match(matcher, i, seq)) {
4414 ret = true;
4415 } else if (0 < cmax) {
4416 matcher.locals[countIndex] = 1;
4417 ret = body.match(matcher, i, seq);
4418 }
4419 matcher.locals[countIndex] = save;
4420 return ret;
4421 }
4422 boolean study(TreeInfo info) {
4423 info.maxValid = false;
4424 info.deterministic = false;
4425 return false;
4426 }
4427 }
4428
4429 /**
4430 * Refers to a group in the regular expression. Attempts to match
4431 * whatever the group referred to last matched.
4432 */
4433 static class BackRef extends Node {
4434 int groupIndex;
4435 BackRef(int groupCount) {
4436 super();
4437 groupIndex = groupCount + groupCount;
4438 }
4439 boolean match(Matcher matcher, int i, CharSequence seq) {
4440 int j = matcher.groups[groupIndex];
4441 int k = matcher.groups[groupIndex+1];
4442
4443 int groupSize = k - j;
4444
4445 // If the referenced group didn't match, neither can this
4446 if (j < 0)
4447 return false;
4448
4449 // If there isn't enough input left no match
4450 if (i + groupSize > matcher.to) {
4451 matcher.hitEnd = true;
4452 return false;
4453 }
4454
4455 // Check each new char to make sure it matches what the group
4456 // referenced matched last time around
4457 for (int index=0; index<groupSize; index++)
4458 if (seq.charAt(i+index) != seq.charAt(j+index))
4459 return false;
4460
4461 return next.match(matcher, i+groupSize, seq);
4462 }
4463 boolean study(TreeInfo info) {
4464 info.maxValid = false;
4465 return next.study(info);
4466 }
4467 }
4468
4469 static class CIBackRef extends Node {
4470 int groupIndex;
4471 boolean doUnicodeCase;
4472 CIBackRef(int groupCount, boolean doUnicodeCase) {
4473 super();
4474 groupIndex = groupCount + groupCount;
4475 this.doUnicodeCase = doUnicodeCase;
4476 }
4477 boolean match(Matcher matcher, int i, CharSequence seq) {
4478 int j = matcher.groups[groupIndex];
4479 int k = matcher.groups[groupIndex+1];
4480
4481 int groupSize = k - j;
4482
4483 // If the referenced group didn't match, neither can this
4484 if (j < 0)
4485 return false;
4486
4487 // If there isn't enough input left no match
4488 if (i + groupSize > matcher.to) {
4489 matcher.hitEnd = true;
4490 return false;
4491 }
4492
4493 // Check each new char to make sure it matches what the group
4494 // referenced matched last time around
4495 int x = i;
4496 for (int index=0; index<groupSize; index++) {
4497 int c1 = Character.codePointAt(seq, x);
4498 int c2 = Character.codePointAt(seq, j);
4499 if (c1 != c2) {
4500 if (doUnicodeCase) {
4501 int cc1 = Character.toUpperCase(c1);
4502 int cc2 = Character.toUpperCase(c2);
4503 if (cc1 != cc2 &&
4504 Character.toLowerCase(cc1) !=
4505 Character.toLowerCase(cc2))
4506 return false;
4507 } else {
4508 if (ASCII.toLower(c1) != ASCII.toLower(c2))
4509 return false;
4510 }
4511 }
4512 x += Character.charCount(c1);
4513 j += Character.charCount(c2);
4514 }
4515
4516 return next.match(matcher, i+groupSize, seq);
4517 }
4518 boolean study(TreeInfo info) {
4519 info.maxValid = false;
4520 return next.study(info);
4521 }
4522 }
4523
4524 /**
4525 * Searches until the next instance of its atom. This is useful for
4526 * finding the atom efficiently without passing an instance of it
4527 * (greedy problem) and without a lot of wasted search time (reluctant
4528 * problem).
4529 */
4530 static final class First extends Node {
4531 Node atom;
4532 First(Node node) {
4533 this.atom = BnM.optimize(node);
4534 }
4535 boolean match(Matcher matcher, int i, CharSequence seq) {
4536 if (atom instanceof BnM) {
4537 return atom.match(matcher, i, seq)
4538 && next.match(matcher, matcher.last, seq);
4539 }
4540 for (;;) {
4541 if (i > matcher.to) {
4542 matcher.hitEnd = true;
4543 return false;
4544 }
4545 if (atom.match(matcher, i, seq)) {
4546 return next.match(matcher, matcher.last, seq);
4547 }
4548 i += countChars(seq, i, 1);
4549 matcher.first++;
4550 }
4551 }
4552 boolean study(TreeInfo info) {
4553 atom.study(info);
4554 info.maxValid = false;
4555 info.deterministic = false;
4556 return next.study(info);
4557 }
4558 }
4559
4560 static final class Conditional extends Node {
4561 Node cond, yes, not;
4562 Conditional(Node cond, Node yes, Node not) {
4563 this.cond = cond;
4564 this.yes = yes;
4565 this.not = not;
4566 }
4567 boolean match(Matcher matcher, int i, CharSequence seq) {
4568 if (cond.match(matcher, i, seq)) {
4569 return yes.match(matcher, i, seq);
4570 } else {
4571 return not.match(matcher, i, seq);
4572 }
4573 }
4574 boolean study(TreeInfo info) {
4575 int minL = info.minLength;
4576 int maxL = info.maxLength;
4577 boolean maxV = info.maxValid;
4578 info.reset();
4579 yes.study(info);
4580
4581 int minL2 = info.minLength;
4582 int maxL2 = info.maxLength;
4583 boolean maxV2 = info.maxValid;
4584 info.reset();
4585 not.study(info);
4586
4587 info.minLength = minL + Math.min(minL2, info.minLength);
4588 info.maxLength = maxL + Math.max(maxL2, info.maxLength);
4589 info.maxValid = (maxV & maxV2 & info.maxValid);
4590 info.deterministic = false;
4591 return next.study(info);
4592 }
4593 }
4594
4595 /**
4596 * Zero width positive lookahead.
4597 */
4598 static final class Pos extends Node {
4599 Node cond;
4600 Pos(Node cond) {
4601 this.cond = cond;
4602 }
4603 boolean match(Matcher matcher, int i, CharSequence seq) {
4604 int savedTo = matcher.to;
4605 boolean conditionMatched = false;
4606
4607 // Relax transparent region boundaries for lookahead
4608 if (matcher.transparentBounds)
4609 matcher.to = matcher.getTextLength();
4610 try {
4611 conditionMatched = cond.match(matcher, i, seq);
4612 } finally {
4613 // Reinstate region boundaries
4614 matcher.to = savedTo;
4615 }
4616 return conditionMatched && next.match(matcher, i, seq);
4617 }
4618 }
4619
4620 /**
4621 * Zero width negative lookahead.
4622 */
4623 static final class Neg extends Node {
4624 Node cond;
4625 Neg(Node cond) {
4626 this.cond = cond;
4627 }
4628 boolean match(Matcher matcher, int i, CharSequence seq) {
4629 int savedTo = matcher.to;
4630 boolean conditionMatched = false;
4631
4632 // Relax transparent region boundaries for lookahead
4633 if (matcher.transparentBounds)
4634 matcher.to = matcher.getTextLength();
4635 try {
4636 if (i < matcher.to) {
4637 conditionMatched = !cond.match(matcher, i, seq);
4638 } else {
4639 // If a negative lookahead succeeds then more input
4640 // could cause it to fail!
4641 matcher.requireEnd = true;
4642 conditionMatched = !cond.match(matcher, i, seq);
4643 }
4644 } finally {
4645 // Reinstate region boundaries
4646 matcher.to = savedTo;
4647 }
4648 return conditionMatched && next.match(matcher, i, seq);
4649 }
4650 }
4651
4652 /**
4653 * For use with lookbehinds; matches the position where the lookbehind
4654 * was encountered.
4655 */
4656 static Node lookbehindEnd = new Node() {
4657 boolean match(Matcher matcher, int i, CharSequence seq) {
4658 return i == matcher.lookbehindTo;
4659 }
4660 };
4661
4662 /**
4663 * Zero width positive lookbehind.
4664 */
4665 static class Behind extends Node {
4666 Node cond;
4667 int rmax, rmin;
4668 Behind(Node cond, int rmax, int rmin) {
4669 this.cond = cond;
4670 this.rmax = rmax;
4671 this.rmin = rmin;
4672 }
4673
4674 boolean match(Matcher matcher, int i, CharSequence seq) {
4675 int savedFrom = matcher.from;
4676 boolean conditionMatched = false;
4677 int startIndex = (!matcher.transparentBounds) ?
4678 matcher.from : 0;
4679 int from = Math.max(i - rmax, startIndex);
4680 // Set end boundary
4681 int savedLBT = matcher.lookbehindTo;
4682 matcher.lookbehindTo = i;
4683 // Relax transparent region boundaries for lookbehind
4684 if (matcher.transparentBounds)
4685 matcher.from = 0;
4686 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
4687 conditionMatched = cond.match(matcher, j, seq);
4688 }
4689 matcher.from = savedFrom;
4690 matcher.lookbehindTo = savedLBT;
4691 return conditionMatched && next.match(matcher, i, seq);
4692 }
4693 }
4694
4695 /**
4696 * Zero width positive lookbehind, including supplementary
4697 * characters or unpaired surrogates.
4698 */
4699 static final class BehindS extends Behind {
4700 BehindS(Node cond, int rmax, int rmin) {
4701 super(cond, rmax, rmin);
4702 }
4703 boolean match(Matcher matcher, int i, CharSequence seq) {
4704 int rmaxChars = countChars(seq, i, -rmax);
4705 int rminChars = countChars(seq, i, -rmin);
4706 int savedFrom = matcher.from;
4707 int startIndex = (!matcher.transparentBounds) ?
4708 matcher.from : 0;
4709 boolean conditionMatched = false;
4710 int from = Math.max(i - rmaxChars, startIndex);
4711 // Set end boundary
4712 int savedLBT = matcher.lookbehindTo;
4713 matcher.lookbehindTo = i;
4714 // Relax transparent region boundaries for lookbehind
4715 if (matcher.transparentBounds)
4716 matcher.from = 0;
4717
4718 for (int j = i - rminChars;
4719 !conditionMatched && j >= from;
4720 j -= j>from ? countChars(seq, j, -1) : 1) {
4721 conditionMatched = cond.match(matcher, j, seq);
4722 }
4723 matcher.from = savedFrom;
4724 matcher.lookbehindTo = savedLBT;
4725 return conditionMatched && next.match(matcher, i, seq);
4726 }
4727 }
4728
4729 /**
4730 * Zero width negative lookbehind.
4731 */
4732 static class NotBehind extends Node {
4733 Node cond;
4734 int rmax, rmin;
4735 NotBehind(Node cond, int rmax, int rmin) {
4736 this.cond = cond;
4737 this.rmax = rmax;
4738 this.rmin = rmin;
4739 }
4740
4741 boolean match(Matcher matcher, int i, CharSequence seq) {
4742 int savedLBT = matcher.lookbehindTo;
4743 int savedFrom = matcher.from;
4744 boolean conditionMatched = false;
4745 int startIndex = (!matcher.transparentBounds) ?
4746 matcher.from : 0;
4747 int from = Math.max(i - rmax, startIndex);
4748 matcher.lookbehindTo = i;
4749 // Relax transparent region boundaries for lookbehind
4750 if (matcher.transparentBounds)
4751 matcher.from = 0;
4752 for (int j = i - rmin; !conditionMatched && j >= from; j--) {
4753 conditionMatched = cond.match(matcher, j, seq);
4754 }
4755 // Reinstate region boundaries
4756 matcher.from = savedFrom;
4757 matcher.lookbehindTo = savedLBT;
4758 return !conditionMatched && next.match(matcher, i, seq);
4759 }
4760 }
4761
4762 /**
4763 * Zero width negative lookbehind, including supplementary
4764 * characters or unpaired surrogates.
4765 */
4766 static final class NotBehindS extends NotBehind {
4767 NotBehindS(Node cond, int rmax, int rmin) {
4768 super(cond, rmax, rmin);
4769 }
4770 boolean match(Matcher matcher, int i, CharSequence seq) {
4771 int rmaxChars = countChars(seq, i, -rmax);
4772 int rminChars = countChars(seq, i, -rmin);
4773 int savedFrom = matcher.from;
4774 int savedLBT = matcher.lookbehindTo;
4775 boolean conditionMatched = false;
4776 int startIndex = (!matcher.transparentBounds) ?
4777 matcher.from : 0;
4778 int from = Math.max(i - rmaxChars, startIndex);
4779 matcher.lookbehindTo = i;
4780 // Relax transparent region boundaries for lookbehind
4781 if (matcher.transparentBounds)
4782 matcher.from = 0;
4783 for (int j = i - rminChars;
4784 !conditionMatched && j >= from;
4785 j -= j>from ? countChars(seq, j, -1) : 1) {
4786 conditionMatched = cond.match(matcher, j, seq);
4787 }
4788 //Reinstate region boundaries
4789 matcher.from = savedFrom;
4790 matcher.lookbehindTo = savedLBT;
4791 return !conditionMatched && next.match(matcher, i, seq);
4792 }
4793 }
4794
4795 /**
4796 * Returns the set union of two CharProperty nodes.
4797 */
4798 private static CharProperty union(final CharProperty lhs,
4799 final CharProperty rhs) {
4800 return new CharProperty() {
4801 boolean isSatisfiedBy(int ch) {
4802 return lhs.isSatisfiedBy(ch) || rhs.isSatisfiedBy(ch);}};
4803 }
4804
4805 /**
4806 * Returns the set intersection of two CharProperty nodes.
4807 */
4808 private static CharProperty intersection(final CharProperty lhs,
4809 final CharProperty rhs) {
4810 return new CharProperty() {
4811 boolean isSatisfiedBy(int ch) {
4812 return lhs.isSatisfiedBy(ch) && rhs.isSatisfiedBy(ch);}};
4813 }
4814
4815 /**
4816 * Returns the set difference of two CharProperty nodes.
4817 */
4818 private static CharProperty setDifference(final CharProperty lhs,
4819 final CharProperty rhs) {
4820 return new CharProperty() {
4821 boolean isSatisfiedBy(int ch) {
4822 return ! rhs.isSatisfiedBy(ch) && lhs.isSatisfiedBy(ch);}};
4823 }
4824
4825 /**
4826 * Handles word boundaries. Includes a field to allow this one class to
4827 * deal with the different types of word boundaries we can match. The word
4828 * characters include underscores, letters, and digits. Non spacing marks
4829 * can are also part of a word if they have a base character, otherwise
4830 * they are ignored for purposes of finding word boundaries.
4831 */
4832 static final class Bound extends Node {
4833 static int LEFT = 0x1;
4834 static int RIGHT= 0x2;
4835 static int BOTH = 0x3;
4836 static int NONE = 0x4;
4837 int type;
4838 Bound(int n) {
4839 type = n;
4840 }
4841 int check(Matcher matcher, int i, CharSequence seq) {
4842 int ch;
4843 boolean left = false;
4844 int startIndex = matcher.from;
4845 int endIndex = matcher.to;
4846 if (matcher.transparentBounds) {
4847 startIndex = 0;
4848 endIndex = matcher.getTextLength();
4849 }
4850 if (i > startIndex) {
4851 ch = Character.codePointBefore(seq, i);
4852 left = (ch == '_' || Character.isLetterOrDigit(ch) ||
4853 ((Character.getType(ch) == Character.NON_SPACING_MARK)
4854 && hasBaseCharacter(matcher, i-1, seq)));
4855 }
4856 boolean right = false;
4857 if (i < endIndex) {
4858 ch = Character.codePointAt(seq, i);
4859 right = (ch == '_' || Character.isLetterOrDigit(ch) ||
4860 ((Character.getType(ch) == Character.NON_SPACING_MARK)
4861 && hasBaseCharacter(matcher, i, seq)));
4862 } else {
4863 // Tried to access char past the end
4864 matcher.hitEnd = true;
4865 // The addition of another char could wreck a boundary
4866 matcher.requireEnd = true;
4867 }
4868 return ((left ^ right) ? (right ? LEFT : RIGHT) : NONE);
4869 }
4870 boolean match(Matcher matcher, int i, CharSequence seq) {
4871 return (check(matcher, i, seq) & type) > 0
4872 && next.match(matcher, i, seq);
4873 }
4874 }
4875
4876 /**
4877 * Non spacing marks only count as word characters in bounds calculations
4878 * if they have a base character.
4879 */
4880 private static boolean hasBaseCharacter(Matcher matcher, int i,
4881 CharSequence seq)
4882 {
4883 int start = (!matcher.transparentBounds) ?
4884 matcher.from : 0;
4885 for (int x=i; x >= start; x--) {
4886 int ch = Character.codePointAt(seq, x);
4887 if (Character.isLetterOrDigit(ch))
4888 return true;
4889 if (Character.getType(ch) == Character.NON_SPACING_MARK)
4890 continue;
4891 return false;
4892 }
4893 return false;
4894 }
4895
4896 /**
4897 * Attempts to match a slice in the input using the Boyer-Moore string
4898 * matching algorithm. The algorithm is based on the idea that the
4899 * pattern can be shifted farther ahead in the search text if it is
4900 * matched right to left.
4901 * <p>
4902 * The pattern is compared to the input one character at a time, from
4903 * the rightmost character in the pattern to the left. If the characters
4904 * all match the pattern has been found. If a character does not match,
4905 * the pattern is shifted right a distance that is the maximum of two
4906 * functions, the bad character shift and the good suffix shift. This
4907 * shift moves the attempted match position through the input more
4908 * quickly than a naive one position at a time check.
4909 * <p>
4910 * The bad character shift is based on the character from the text that
4911 * did not match. If the character does not appear in the pattern, the
4912 * pattern can be shifted completely beyond the bad character. If the
4913 * character does occur in the pattern, the pattern can be shifted to
4914 * line the pattern up with the next occurrence of that character.
4915 * <p>
4916 * The good suffix shift is based on the idea that some subset on the right
4917 * side of the pattern has matched. When a bad character is found, the
4918 * pattern can be shifted right by the pattern length if the subset does
4919 * not occur again in pattern, or by the amount of distance to the
4920 * next occurrence of the subset in the pattern.
4921 *
4922 * Boyer-Moore search methods adapted from code by Amy Yu.
4923 */
4924 static class BnM extends Node {
4925 int[] buffer;
4926 int[] lastOcc;
4927 int[] optoSft;
4928
4929 /**
4930 * Pre calculates arrays needed to generate the bad character
4931 * shift and the good suffix shift. Only the last seven bits
4932 * are used to see if chars match; This keeps the tables small
4933 * and covers the heavily used ASCII range, but occasionally
4934 * results in an aliased match for the bad character shift.
4935 */
4936 static Node optimize(Node node) {
4937 if (!(node instanceof Slice)) {
4938 return node;
4939 }
4940
4941 int[] src = ((Slice) node).buffer;
4942 int patternLength = src.length;
4943 // The BM algorithm requires a bit of overhead;
4944 // If the pattern is short don't use it, since
4945 // a shift larger than the pattern length cannot
4946 // be used anyway.
4947 if (patternLength < 4) {
4948 return node;
4949 }
4950 int i, j, k;
4951 int[] lastOcc = new int[128];
4952 int[] optoSft = new int[patternLength];
4953 // Precalculate part of the bad character shift
4954 // It is a table for where in the pattern each
4955 // lower 7-bit value occurs
4956 for (i = 0; i < patternLength; i++) {
4957 lastOcc[src[i]&0x7F] = i + 1;
4958 }
4959 // Precalculate the good suffix shift
4960 // i is the shift amount being considered
4961 NEXT: for (i = patternLength; i > 0; i--) {
4962 // j is the beginning index of suffix being considered
4963 for (j = patternLength - 1; j >= i; j--) {
4964 // Testing for good suffix
4965 if (src[j] == src[j-i]) {
4966 // src[j..len] is a good suffix
4967 optoSft[j-1] = i;
4968 } else {
4969 // No match. The array has already been
4970 // filled up with correct values before.
4971 continue NEXT;
4972 }
4973 }
4974 // This fills up the remaining of optoSft
4975 // any suffix can not have larger shift amount
4976 // then its sub-suffix. Why???
4977 while (j > 0) {
4978 optoSft[--j] = i;
4979 }
4980 }
4981 // Set the guard value because of unicode compression
4982 optoSft[patternLength-1] = 1;
4983 if (node instanceof SliceS)
4984 return new BnMS(src, lastOcc, optoSft, node.next);
4985 return new BnM(src, lastOcc, optoSft, node.next);
4986 }
4987 BnM(int[] src, int[] lastOcc, int[] optoSft, Node next) {
4988 this.buffer = src;
4989 this.lastOcc = lastOcc;
4990 this.optoSft = optoSft;
4991 this.next = next;
4992 }
4993 boolean match(Matcher matcher, int i, CharSequence seq) {
4994 int[] src = buffer;
4995 int patternLength = src.length;
4996 int last = matcher.to - patternLength;
4997
4998 // Loop over all possible match positions in text
4999 NEXT: while (i <= last) {
5000 // Loop over pattern from right to left
5001 for (int j = patternLength - 1; j >= 0; j--) {
5002 int ch = seq.charAt(i+j);
5003 if (ch != src[j]) {
5004 // Shift search to the right by the maximum of the
5005 // bad character shift and the good suffix shift
5006 i += Math.max(j + 1 - lastOcc[ch&0x7F], optoSft[j]);
5007 continue NEXT;
5008 }
5009 }
5010 // Entire pattern matched starting at i
5011 matcher.first = i;
5012 boolean ret = next.match(matcher, i + patternLength, seq);
5013 if (ret) {
5014 matcher.first = i;
5015 matcher.groups[0] = matcher.first;
5016 matcher.groups[1] = matcher.last;
5017 return true;
5018 }
5019 i++;
5020 }
5021 // BnM is only used as the leading node in the unanchored case,
5022 // and it replaced its Start() which always searches to the end
5023 // if it doesn't find what it's looking for, so hitEnd is true.
5024 matcher.hitEnd = true;
5025 return false;
5026 }
5027 boolean study(TreeInfo info) {
5028 info.minLength += buffer.length;
5029 info.maxValid = false;
5030 return next.study(info);
5031 }
5032 }
5033
5034 /**
5035 * Supplementary support version of BnM(). Unpaired surrogates are
5036 * also handled by this class.
5037 */
5038 static final class BnMS extends BnM {
5039 int lengthInChars;
5040
5041 BnMS(int[] src, int[] lastOcc, int[] optoSft, Node next) {
5042 super(src, lastOcc, optoSft, next);
5043 for (int x = 0; x < buffer.length; x++) {
5044 lengthInChars += Character.charCount(buffer[x]);
5045 }
5046 }
5047 boolean match(Matcher matcher, int i, CharSequence seq) {
5048 int[] src = buffer;
5049 int patternLength = src.length;
5050 int last = matcher.to - lengthInChars;
5051
5052 // Loop over all possible match positions in text
5053 NEXT: while (i <= last) {
5054 // Loop over pattern from right to left
5055 int ch;
5056 for (int j = countChars(seq, i, patternLength), x = patternLength - 1;
5057 j > 0; j -= Character.charCount(ch), x--) {
5058 ch = Character.codePointBefore(seq, i+j);
5059 if (ch != src[x]) {
5060 // Shift search to the right by the maximum of the
5061 // bad character shift and the good suffix shift
5062 int n = Math.max(x + 1 - lastOcc[ch&0x7F], optoSft[x]);
5063 i += countChars(seq, i, n);
5064 continue NEXT;
5065 }
5066 }
5067 // Entire pattern matched starting at i
5068 matcher.first = i;
5069 boolean ret = next.match(matcher, i + lengthInChars, seq);
5070 if (ret) {
5071 matcher.first = i;
5072 matcher.groups[0] = matcher.first;
5073 matcher.groups[1] = matcher.last;
5074 return true;
5075 }
5076 i += countChars(seq, i, 1);
5077 }
5078 matcher.hitEnd = true;
5079 return false;
5080 }
5081 }
5082
5083 ///////////////////////////////////////////////////////////////////////////////
5084 ///////////////////////////////////////////////////////////////////////////////
5085
5086 /**
5087 * This must be the very first initializer.
5088 */
5089 static Node accept = new Node();
5090
5091 static Node lastAccept = new LastNode();
5092
5093 private static class CharPropertyNames {
5094
5095 static CharProperty charPropertyFor(String name) {
5096 CharPropertyFactory m = map.get(name);
5097 return m == null ? null : m.make();
5098 }
5099
5100 private static abstract class CharPropertyFactory {
5101 abstract CharProperty make();
5102 }
5103
5104 private static void defCategory(String name,
5105 final int typeMask) {
5106 map.put(name, new CharPropertyFactory() {
5107 CharProperty make() { return new Category(typeMask);}});
5108 }
5109
5110 private static void defRange(String name,
5111 final int lower, final int upper) {
5112 map.put(name, new CharPropertyFactory() {
5113 CharProperty make() { return rangeFor(lower, upper);}});
5114 }
5115
5116 private static void defCtype(String name,
5117 final int ctype) {
5118 map.put(name, new CharPropertyFactory() {
5119 CharProperty make() { return new Ctype(ctype);}});
5120 }
5121
5122 private static abstract class CloneableProperty
5123 extends CharProperty implements Cloneable
5124 {
5125 public CloneableProperty clone() {
5126 try {
5127 return (CloneableProperty) super.clone();
5128 } catch (CloneNotSupportedException e) {
5129 throw new AssertionError(e);
5130 }
5131 }
5132 }
5133
5134 private static void defClone(String name,
5135 final CloneableProperty p) {
5136 map.put(name, new CharPropertyFactory() {
5137 CharProperty make() { return p.clone();}});
5138 }
5139
5140 private static final HashMap<String, CharPropertyFactory> map
5141 = new HashMap<String, CharPropertyFactory>();
5142
5143 static {
5144 // Unicode character property aliases, defined in
5145 // http://www.unicode.org/Public/UNIDATA/PropertyValueAliases.txt
5146 defCategory("Cn", 1<<Character.UNASSIGNED);
5147 defCategory("Lu", 1<<Character.UPPERCASE_LETTER);
5148 defCategory("Ll", 1<<Character.LOWERCASE_LETTER);
5149 defCategory("Lt", 1<<Character.TITLECASE_LETTER);
5150 defCategory("Lm", 1<<Character.MODIFIER_LETTER);
5151 defCategory("Lo", 1<<Character.OTHER_LETTER);
5152 defCategory("Mn", 1<<Character.NON_SPACING_MARK);
5153 defCategory("Me", 1<<Character.ENCLOSING_MARK);
5154 defCategory("Mc", 1<<Character.COMBINING_SPACING_MARK);
5155 defCategory("Nd", 1<<Character.DECIMAL_DIGIT_NUMBER);
5156 defCategory("Nl", 1<<Character.LETTER_NUMBER);
5157 defCategory("No", 1<<Character.OTHER_NUMBER);
5158 defCategory("Zs", 1<<Character.SPACE_SEPARATOR);
5159 defCategory("Zl", 1<<Character.LINE_SEPARATOR);
5160 defCategory("Zp", 1<<Character.PARAGRAPH_SEPARATOR);
5161 defCategory("Cc", 1<<Character.CONTROL);
5162 defCategory("Cf", 1<<Character.FORMAT);
5163 defCategory("Co", 1<<Character.PRIVATE_USE);
5164 defCategory("Cs", 1<<Character.SURROGATE);
5165 defCategory("Pd", 1<<Character.DASH_PUNCTUATION);
5166 defCategory("Ps", 1<<Character.START_PUNCTUATION);
5167 defCategory("Pe", 1<<Character.END_PUNCTUATION);
5168 defCategory("Pc", 1<<Character.CONNECTOR_PUNCTUATION);
5169 defCategory("Po", 1<<Character.OTHER_PUNCTUATION);
5170 defCategory("Sm", 1<<Character.MATH_SYMBOL);
5171 defCategory("Sc", 1<<Character.CURRENCY_SYMBOL);
5172 defCategory("Sk", 1<<Character.MODIFIER_SYMBOL);
5173 defCategory("So", 1<<Character.OTHER_SYMBOL);
5174 defCategory("Pi", 1<<Character.INITIAL_QUOTE_PUNCTUATION);
5175 defCategory("Pf", 1<<Character.FINAL_QUOTE_PUNCTUATION);
5176 defCategory("L", ((1<<Character.UPPERCASE_LETTER) |
5177 (1<<Character.LOWERCASE_LETTER) |
5178 (1<<Character.TITLECASE_LETTER) |
5179 (1<<Character.MODIFIER_LETTER) |
5180 (1<<Character.OTHER_LETTER)));
5181 defCategory("M", ((1<<Character.NON_SPACING_MARK) |
5182 (1<<Character.ENCLOSING_MARK) |
5183 (1<<Character.COMBINING_SPACING_MARK)));
5184 defCategory("N", ((1<<Character.DECIMAL_DIGIT_NUMBER) |
5185 (1<<Character.LETTER_NUMBER) |
5186 (1<<Character.OTHER_NUMBER)));
5187 defCategory("Z", ((1<<Character.SPACE_SEPARATOR) |
5188 (1<<Character.LINE_SEPARATOR) |
5189 (1<<Character.PARAGRAPH_SEPARATOR)));
5190 defCategory("C", ((1<<Character.CONTROL) |
5191 (1<<Character.FORMAT) |
5192 (1<<Character.PRIVATE_USE) |
5193 (1<<Character.SURROGATE))); // Other
5194 defCategory("P", ((1<<Character.DASH_PUNCTUATION) |
5195 (1<<Character.START_PUNCTUATION) |
5196 (1<<Character.END_PUNCTUATION) |
5197 (1<<Character.CONNECTOR_PUNCTUATION) |
5198 (1<<Character.OTHER_PUNCTUATION) |
5199 (1<<Character.INITIAL_QUOTE_PUNCTUATION) |
5200 (1<<Character.FINAL_QUOTE_PUNCTUATION)));
5201 defCategory("S", ((1<<Character.MATH_SYMBOL) |
5202 (1<<Character.CURRENCY_SYMBOL) |
5203 (1<<Character.MODIFIER_SYMBOL) |
5204 (1<<Character.OTHER_SYMBOL)));
5205 defCategory("LC", ((1<<Character.UPPERCASE_LETTER) |
5206 (1<<Character.LOWERCASE_LETTER) |
5207 (1<<Character.TITLECASE_LETTER)));
5208 defCategory("LD", ((1<<Character.UPPERCASE_LETTER) |
5209 (1<<Character.LOWERCASE_LETTER) |
5210 (1<<Character.TITLECASE_LETTER) |
5211 (1<<Character.MODIFIER_LETTER) |
5212 (1<<Character.OTHER_LETTER) |
5213 (1<<Character.DECIMAL_DIGIT_NUMBER)));
5214 defRange("L1", 0x00, 0xFF); // Latin-1
5215 map.put("all", new CharPropertyFactory() {
5216 CharProperty make() { return new All(); }});
5217
5218 // Posix regular expression character classes, defined in
5219 // http://www.unix.org/onlinepubs/009695399/basedefs/xbd_chap09.html
5220 defRange("ASCII", 0x00, 0x7F); // ASCII
5221 defCtype("Alnum", ASCII.ALNUM); // Alphanumeric characters
5222 defCtype("Alpha", ASCII.ALPHA); // Alphabetic characters
5223 defCtype("Blank", ASCII.BLANK); // Space and tab characters
5224 defCtype("Cntrl", ASCII.CNTRL); // Control characters
5225 defRange("Digit", '0', '9'); // Numeric characters
5226 defCtype("Graph", ASCII.GRAPH); // printable and visible
5227 defRange("Lower", 'a', 'z'); // Lower-case alphabetic
5228 defRange("Print", 0x20, 0x7E); // Printable characters
5229 defCtype("Punct", ASCII.PUNCT); // Punctuation characters
5230 defCtype("Space", ASCII.SPACE); // Space characters
5231 defRange("Upper", 'A', 'Z'); // Upper-case alphabetic
5232 defCtype("XDigit",ASCII.XDIGIT); // hexadecimal digits
5233
5234 // Java character properties, defined by methods in Character.java
5235 defClone("javaLowerCase", new CloneableProperty() {
5236 boolean isSatisfiedBy(int ch) {
5237 return Character.isLowerCase(ch);}});
5238 defClone("javaUpperCase", new CloneableProperty() {
5239 boolean isSatisfiedBy(int ch) {
5240 return Character.isUpperCase(ch);}});
5241 defClone("javaTitleCase", new CloneableProperty() {
5242 boolean isSatisfiedBy(int ch) {
5243 return Character.isTitleCase(ch);}});
5244 defClone("javaDigit", new CloneableProperty() {
5245 boolean isSatisfiedBy(int ch) {
5246 return Character.isDigit(ch);}});
5247 defClone("javaDefined", new CloneableProperty() {
5248 boolean isSatisfiedBy(int ch) {
5249 return Character.isDefined(ch);}});
5250 defClone("javaLetter", new CloneableProperty() {
5251 boolean isSatisfiedBy(int ch) {
5252 return Character.isLetter(ch);}});
5253 defClone("javaLetterOrDigit", new CloneableProperty() {
5254 boolean isSatisfiedBy(int ch) {
5255 return Character.isLetterOrDigit(ch);}});
5256 defClone("javaJavaIdentifierStart", new CloneableProperty() {
5257 boolean isSatisfiedBy(int ch) {
5258 return Character.isJavaIdentifierStart(ch);}});
5259 defClone("javaJavaIdentifierPart", new CloneableProperty() {
5260 boolean isSatisfiedBy(int ch) {
5261 return Character.isJavaIdentifierPart(ch);}});
5262 defClone("javaUnicodeIdentifierStart", new CloneableProperty() {
5263 boolean isSatisfiedBy(int ch) {
5264 return Character.isUnicodeIdentifierStart(ch);}});
5265 defClone("javaUnicodeIdentifierPart", new CloneableProperty() {
5266 boolean isSatisfiedBy(int ch) {
5267 return Character.isUnicodeIdentifierPart(ch);}});
5268 defClone("javaIdentifierIgnorable", new CloneableProperty() {
5269 boolean isSatisfiedBy(int ch) {
5270 return Character.isIdentifierIgnorable(ch);}});
5271 defClone("javaSpaceChar", new CloneableProperty() {
5272 boolean isSatisfiedBy(int ch) {
5273 return Character.isSpaceChar(ch);}});
5274 defClone("javaWhitespace", new CloneableProperty() {
5275 boolean isSatisfiedBy(int ch) {
5276 return Character.isWhitespace(ch);}});
5277 defClone("javaISOControl", new CloneableProperty() {
5278 boolean isSatisfiedBy(int ch) {
5279 return Character.isISOControl(ch);}});
5280 defClone("javaMirrored", new CloneableProperty() {
5281 boolean isSatisfiedBy(int ch) {
5282 return Character.isMirrored(ch);}});
5283 }
5284 }
5285 }
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