author | sherman |
Tue, 30 Aug 2011 11:53:11 -0700 | |
changeset 10419 | 12c063b39232 |
parent 7668 | d4a77089c587 |
child 12848 | da701d422d2c |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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/* |
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* |
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* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved |
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* (C) Copyright IBM Corp. 1996 - 2002 - All Rights Reserved |
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* |
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* The original version of this source code and documentation |
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* is copyrighted and owned by Taligent, Inc., a wholly-owned |
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* subsidiary of IBM. These materials are provided under terms |
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* of a License Agreement between Taligent and Sun. This technology |
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* is protected by multiple US and International patents. |
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* |
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* This notice and attribution to Taligent may not be removed. |
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* Taligent is a registered trademark of Taligent, Inc. |
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*/ |
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package java.text; |
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import java.io.BufferedInputStream; |
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import java.io.IOException; |
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import java.security.AccessController; |
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import java.security.PrivilegedActionException; |
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import java.security.PrivilegedExceptionAction; |
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import java.util.Vector; |
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import java.util.Stack; |
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import java.util.Hashtable; |
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import java.util.Enumeration; |
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import java.util.MissingResourceException; |
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import java.text.CharacterIterator; |
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import java.text.StringCharacterIterator; |
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import sun.text.CompactByteArray; |
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import sun.text.SupplementaryCharacterData; |
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/** |
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* <p>A subclass of BreakIterator whose behavior is specified using a list of rules.</p> |
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* |
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* <p>There are two kinds of rules, which are separated by semicolons: <i>substitutions</i> |
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* and <i>regular expressions.</i></p> |
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* |
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* <p>A substitution rule defines a name that can be used in place of an expression. It |
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* consists of a name, which is a string of characters contained in angle brackets, an equals |
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* sign, and an expression. (There can be no whitespace on either side of the equals sign.) |
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* To keep its syntactic meaning intact, the expression must be enclosed in parentheses or |
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* square brackets. A substitution is visible after its definition, and is filled in using |
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* simple textual substitution. Substitution definitions can contain other substitutions, as |
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* long as those substitutions have been defined first. Substitutions are generally used to |
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* make the regular expressions (which can get quite complex) shorted and easier to read. |
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* They typically define either character categories or commonly-used subexpressions.</p> |
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* |
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* <p>There is one special substitution. If the description defines a substitution |
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* called "<ignore>", the expression must be a [] expression, and the |
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* expression defines a set of characters (the "<em>ignore characters</em>") that |
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* will be transparent to the BreakIterator. A sequence of characters will break the |
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* same way it would if any ignore characters it contains are taken out. Break |
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* positions never occur befoer ignore characters.</p> |
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* |
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* <p>A regular expression uses a subset of the normal Unix regular-expression syntax, and |
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* defines a sequence of characters to be kept together. With one significant exception, the |
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* iterator uses a longest-possible-match algorithm when matching text to regular |
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* expressions. The iterator also treats descriptions containing multiple regular expressions |
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* as if they were ORed together (i.e., as if they were separated by |).</p> |
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* |
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* <p>The special characters recognized by the regular-expression parser are as follows:</p> |
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* |
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* <blockquote> |
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* <table border="1" width="100%"> |
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* <tr> |
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* <td width="6%">*</td> |
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* <td width="94%">Specifies that the expression preceding the asterisk may occur any number |
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* of times (including not at all).</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">{}</td> |
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* <td width="94%">Encloses a sequence of characters that is optional.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">()</td> |
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* <td width="94%">Encloses a sequence of characters. If followed by *, the sequence |
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* repeats. Otherwise, the parentheses are just a grouping device and a way to delimit |
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* the ends of expressions containing |.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">|</td> |
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* <td width="94%">Separates two alternative sequences of characters. Either one |
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* sequence or the other, but not both, matches this expression. The | character can |
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* only occur inside ().</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">.</td> |
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* <td width="94%">Matches any character.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">*?</td> |
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* <td width="94%">Specifies a non-greedy asterisk. *? works the same way as *, except |
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* when there is overlap between the last group of characters in the expression preceding the |
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* * and the first group of characters following the *. When there is this kind of |
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* overlap, * will match the longest sequence of characters that match the expression before |
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* the *, and *? will match the shortest sequence of characters matching the expression |
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* before the *?. For example, if you have "xxyxyyyxyxyxxyxyxyy" in the text, |
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* "x[xy]*x" will match through to the last x (i.e., "<strong>xxyxyyyxyxyxxyxyx</strong>yy", |
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* but "x[xy]*?x" will only match the first two xes ("<strong>xx</strong>yxyyyxyxyxxyxyxyy").</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">[]</td> |
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* <td width="94%">Specifies a group of alternative characters. A [] expression will |
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* match any single character that is specified in the [] expression. For more on the |
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* syntax of [] expressions, see below.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">/</td> |
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* <td width="94%">Specifies where the break position should go if text matches this |
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* expression. (e.g., "[a-z]*/[:Zs:]*[1-0]" will match if the iterator sees a run |
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* of letters, followed by a run of whitespace, followed by a digit, but the break position |
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* will actually go before the whitespace). Expressions that don't contain / put the |
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* break position at the end of the matching text.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">\</td> |
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* <td width="94%">Escape character. The \ itself is ignored, but causes the next |
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* character to be treated as literal character. This has no effect for many |
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* characters, but for the characters listed above, this deprives them of their special |
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* meaning. (There are no special escape sequences for Unicode characters, or tabs and |
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* newlines; these are all handled by a higher-level protocol. In a Java string, |
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* "\n" will be converted to a literal newline character by the time the |
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* regular-expression parser sees it. Of course, this means that \ sequences that are |
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* visible to the regexp parser must be written as \\ when inside a Java string.) All |
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* characters in the ASCII range except for letters, digits, and control characters are |
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* reserved characters to the parser and must be preceded by \ even if they currently don't |
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* mean anything.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">!</td> |
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* <td width="94%">If ! appears at the beginning of a regular expression, it tells the regexp |
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* parser that this expression specifies the backwards-iteration behavior of the iterator, |
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* and not its normal iteration behavior. This is generally only used in situations |
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* where the automatically-generated backwards-iteration brhavior doesn't produce |
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* satisfactory results and must be supplemented with extra client-specified rules.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%"><em>(all others)</em></td> |
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* <td width="94%">All other characters are treated as literal characters, which must match |
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* the corresponding character(s) in the text exactly.</td> |
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* </tr> |
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* </table> |
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* </blockquote> |
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* |
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* <p>Within a [] expression, a number of other special characters can be used to specify |
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* groups of characters:</p> |
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* |
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* <blockquote> |
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* <table border="1" width="100%"> |
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* <tr> |
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* <td width="6%">-</td> |
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* <td width="94%">Specifies a range of matching characters. For example |
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* "[a-p]" matches all lowercase Latin letters from a to p (inclusive). The - |
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* sign specifies ranges of continuous Unicode numeric values, not ranges of characters in a |
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* language's alphabetical order: "[a-z]" doesn't include capital letters, nor does |
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* it include accented letters such as a-umlaut.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">::</td> |
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* <td width="94%">A pair of colons containing a one- or two-letter code matches all |
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* characters in the corresponding Unicode category. The two-letter codes are the same |
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* as the two-letter codes in the Unicode database (for example, "[:Sc::Sm:]" |
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* matches all currency symbols and all math symbols). Specifying a one-letter code is |
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* the same as specifying all two-letter codes that begin with that letter (for example, |
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* "[:L:]" matches all letters, and is equivalent to |
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* "[:Lu::Ll::Lo::Lm::Lt:]"). Anything other than a valid two-letter Unicode |
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* category code or a single letter that begins a Unicode category code is illegal within |
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* colons.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">[]</td> |
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* <td width="94%">[] expressions can nest. This has no effect, except when used in |
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* conjunction with the ^ token.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%">^</td> |
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* <td width="94%">Excludes the character (or the characters in the [] expression) following |
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* it from the group of characters. For example, "[a-z^p]" matches all Latin |
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* lowercase letters except p. "[:L:^[\u4e00-\u9fff]]" matches all letters |
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* except the Han ideographs.</td> |
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* </tr> |
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* <tr> |
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* <td width="6%"><em>(all others)</em></td> |
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* <td width="94%">All other characters are treated as literal characters. (For |
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* example, "[aeiou]" specifies just the letters a, e, i, o, and u.)</td> |
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* </tr> |
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* </table> |
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* </blockquote> |
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* |
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* <p>For a more complete explanation, see <a |
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* href="http://www.ibm.com/java/education/boundaries/boundaries.html">http://www.ibm.com/java/education/boundaries/boundaries.html</a>. |
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* For examples, see the resource data (which is annotated).</p> |
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* |
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* @author Richard Gillam |
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*/ |
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class RuleBasedBreakIterator extends BreakIterator { |
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/** |
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* A token used as a character-category value to identify ignore characters |
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*/ |
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protected static final byte IGNORE = -1; |
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/** |
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* The state number of the starting state |
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*/ |
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private static final short START_STATE = 1; |
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/** |
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* The state-transition value indicating "stop" |
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*/ |
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private static final short STOP_STATE = 0; |
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/** |
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* Magic number for the BreakIterator data file format. |
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*/ |
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static final byte[] LABEL = { |
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(byte)'B', (byte)'I', (byte)'d', (byte)'a', (byte)'t', (byte)'a', |
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(byte)'\0' |
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}; |
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static final int LABEL_LENGTH = LABEL.length; |
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/** |
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* Version number of the dictionary that was read in. |
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*/ |
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static final byte supportedVersion = 1; |
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/** |
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* Header size in byte count |
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*/ |
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private static final int HEADER_LENGTH = 36; |
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/** |
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* An array length of indices for BMP characters |
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*/ |
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private static final int BMP_INDICES_LENGTH = 512; |
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/** |
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* Tables that indexes from character values to character category numbers |
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*/ |
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private CompactByteArray charCategoryTable = null; |
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private SupplementaryCharacterData supplementaryCharCategoryTable = null; |
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/** |
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* The table of state transitions used for forward iteration |
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*/ |
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private short[] stateTable = null; |
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/** |
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* The table of state transitions used to sync up the iterator with the |
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* text in backwards and random-access iteration |
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*/ |
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private short[] backwardsStateTable = null; |
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/** |
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* A list of flags indicating which states in the state table are accepting |
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* ("end") states |
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*/ |
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private boolean[] endStates = null; |
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/** |
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* A list of flags indicating which states in the state table are |
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* lookahead states (states which turn lookahead on and off) |
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*/ |
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private boolean[] lookaheadStates = null; |
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/** |
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* A table for additional data. May be used by a subclass of |
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* RuleBasedBreakIterator. |
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*/ |
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private byte[] additionalData = null; |
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/** |
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* The number of character categories (and, thus, the number of columns in |
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* the state tables) |
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*/ |
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private int numCategories; |
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/** |
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* The character iterator through which this BreakIterator accesses the text |
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*/ |
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private CharacterIterator text = null; |
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/** |
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* A CRC32 value of all data in datafile |
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*/ |
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private long checksum; |
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//======================================================================= |
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// constructors |
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//======================================================================= |
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/** |
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* Constructs a RuleBasedBreakIterator according to the datafile |
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* provided. |
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*/ |
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public RuleBasedBreakIterator(String datafile) |
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throws IOException, MissingResourceException { |
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readTables(datafile); |
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} |
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/** |
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* Read datafile. The datafile's format is as follows: |
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* <pre> |
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* BreakIteratorData { |
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* u1 magic[7]; |
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* u1 version; |
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* u4 totalDataSize; |
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* header_info header; |
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* body value; |
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* } |
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* </pre> |
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* <code>totalDataSize</code> is the summation of the size of |
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* <code>header_info</code> and <code>body</code> in byte count. |
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* <p> |
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* In <code>header</code>, each field except for checksum implies the |
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* length of each field. Since <code>BMPdataLength</code> is a fixed-length |
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* data(512 entries), its length isn't included in <code>header</code>. |
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* <code>checksum</code> is a CRC32 value of all in <code>body</code>. |
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* <pre> |
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* header_info { |
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* u4 stateTableLength; |
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* u4 backwardsStateTableLength; |
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* u4 endStatesLength; |
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* u4 lookaheadStatesLength; |
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* u4 BMPdataLength; |
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* u4 nonBMPdataLength; |
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* u4 additionalDataLength; |
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* u8 checksum; |
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* } |
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* </pre> |
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* <p> |
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* |
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* Finally, <code>BMPindices</code> and <code>BMPdata</code> are set to |
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* <code>charCategoryTable</code>. <code>nonBMPdata</code> is set to |
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* <code>supplementaryCharCategoryTable</code>. |
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* <pre> |
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* body { |
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* u2 stateTable[stateTableLength]; |
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* u2 backwardsStateTable[backwardsStateTableLength]; |
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* u1 endStates[endStatesLength]; |
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* u1 lookaheadStates[lookaheadStatesLength]; |
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* u2 BMPindices[512]; |
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* u1 BMPdata[BMPdataLength]; |
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* u4 nonBMPdata[numNonBMPdataLength]; |
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* u1 additionalData[additionalDataLength]; |
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* } |
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* </pre> |
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*/ |
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protected void readTables(String datafile) |
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throws IOException, MissingResourceException { |
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byte[] buffer = readFile(datafile); |
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/* Read header_info. */ |
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int stateTableLength = BreakIterator.getInt(buffer, 0); |
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int backwardsStateTableLength = BreakIterator.getInt(buffer, 4); |
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int endStatesLength = BreakIterator.getInt(buffer, 8); |
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int lookaheadStatesLength = BreakIterator.getInt(buffer, 12); |
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int BMPdataLength = BreakIterator.getInt(buffer, 16); |
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int nonBMPdataLength = BreakIterator.getInt(buffer, 20); |
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int additionalDataLength = BreakIterator.getInt(buffer, 24); |
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checksum = BreakIterator.getLong(buffer, 28); |
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/* Read stateTable[numCategories * numRows] */ |
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stateTable = new short[stateTableLength]; |
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int offset = HEADER_LENGTH; |
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for (int i = 0; i < stateTableLength; i++, offset+=2) { |
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stateTable[i] = BreakIterator.getShort(buffer, offset); |
|
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} |
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||
397 |
/* Read backwardsStateTable[numCategories * numRows] */ |
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backwardsStateTable = new short[backwardsStateTableLength]; |
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for (int i = 0; i < backwardsStateTableLength; i++, offset+=2) { |
|
400 |
backwardsStateTable[i] = BreakIterator.getShort(buffer, offset); |
|
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} |
|
402 |
||
403 |
/* Read endStates[numRows] */ |
|
404 |
endStates = new boolean[endStatesLength]; |
|
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for (int i = 0; i < endStatesLength; i++, offset++) { |
|
406 |
endStates[i] = buffer[offset] == 1; |
|
407 |
} |
|
408 |
||
409 |
/* Read lookaheadStates[numRows] */ |
|
410 |
lookaheadStates = new boolean[lookaheadStatesLength]; |
|
411 |
for (int i = 0; i < lookaheadStatesLength; i++, offset++) { |
|
412 |
lookaheadStates[i] = buffer[offset] == 1; |
|
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} |
|
414 |
||
415 |
/* Read a category table and indices for BMP characters. */ |
|
416 |
short[] temp1 = new short[BMP_INDICES_LENGTH]; // BMPindices |
|
417 |
for (int i = 0; i < BMP_INDICES_LENGTH; i++, offset+=2) { |
|
418 |
temp1[i] = BreakIterator.getShort(buffer, offset); |
|
419 |
} |
|
420 |
byte[] temp2 = new byte[BMPdataLength]; // BMPdata |
|
421 |
System.arraycopy(buffer, offset, temp2, 0, BMPdataLength); |
|
422 |
offset += BMPdataLength; |
|
423 |
charCategoryTable = new CompactByteArray(temp1, temp2); |
|
424 |
||
425 |
/* Read a category table for non-BMP characters. */ |
|
426 |
int[] temp3 = new int[nonBMPdataLength]; |
|
427 |
for (int i = 0; i < nonBMPdataLength; i++, offset+=4) { |
|
428 |
temp3[i] = BreakIterator.getInt(buffer, offset); |
|
429 |
} |
|
430 |
supplementaryCharCategoryTable = new SupplementaryCharacterData(temp3); |
|
431 |
||
432 |
/* Read additional data */ |
|
433 |
if (additionalDataLength > 0) { |
|
434 |
additionalData = new byte[additionalDataLength]; |
|
435 |
System.arraycopy(buffer, offset, additionalData, 0, additionalDataLength); |
|
436 |
} |
|
437 |
||
438 |
/* Set numCategories */ |
|
439 |
numCategories = stateTable.length / endStates.length; |
|
440 |
} |
|
441 |
||
442 |
protected byte[] readFile(final String datafile) |
|
443 |
throws IOException, MissingResourceException { |
|
444 |
||
445 |
BufferedInputStream is; |
|
446 |
try { |
|
447 |
is = (BufferedInputStream)AccessController.doPrivileged( |
|
448 |
new PrivilegedExceptionAction() { |
|
449 |
public Object run() throws Exception { |
|
450 |
return new BufferedInputStream(getClass().getResourceAsStream("/sun/text/resources/" + datafile)); |
|
451 |
} |
|
452 |
} |
|
453 |
); |
|
454 |
} |
|
455 |
catch (PrivilegedActionException e) { |
|
10419
12c063b39232
7084245: Update usages of InternalError to use exception chaining
sherman
parents:
7668
diff
changeset
|
456 |
throw new InternalError(e.toString(), e); |
2 | 457 |
} |
458 |
||
459 |
int offset = 0; |
|
460 |
||
461 |
/* First, read magic, version, and header_info. */ |
|
462 |
int len = LABEL_LENGTH + 5; |
|
463 |
byte[] buf = new byte[len]; |
|
464 |
if (is.read(buf) != len) { |
|
465 |
throw new MissingResourceException("Wrong header length", |
|
466 |
datafile, ""); |
|
467 |
} |
|
468 |
||
469 |
/* Validate the magic number. */ |
|
470 |
for (int i = 0; i < LABEL_LENGTH; i++, offset++) { |
|
471 |
if (buf[offset] != LABEL[offset]) { |
|
472 |
throw new MissingResourceException("Wrong magic number", |
|
473 |
datafile, ""); |
|
474 |
} |
|
475 |
} |
|
476 |
||
477 |
/* Validate the version number. */ |
|
478 |
if (buf[offset] != supportedVersion) { |
|
479 |
throw new MissingResourceException("Unsupported version(" + buf[offset] + ")", |
|
480 |
datafile, ""); |
|
481 |
} |
|
482 |
||
483 |
/* Read data: totalDataSize + 8(for checksum) */ |
|
484 |
len = BreakIterator.getInt(buf, ++offset); |
|
485 |
buf = new byte[len]; |
|
486 |
if (is.read(buf) != len) { |
|
487 |
throw new MissingResourceException("Wrong data length", |
|
488 |
datafile, ""); |
|
489 |
} |
|
490 |
||
491 |
is.close(); |
|
492 |
||
493 |
return buf; |
|
494 |
} |
|
495 |
||
496 |
byte[] getAdditionalData() { |
|
497 |
return additionalData; |
|
498 |
} |
|
499 |
||
500 |
void setAdditionalData(byte[] b) { |
|
501 |
additionalData = b; |
|
502 |
} |
|
503 |
||
504 |
//======================================================================= |
|
505 |
// boilerplate |
|
506 |
//======================================================================= |
|
507 |
/** |
|
508 |
* Clones this iterator. |
|
509 |
* @return A newly-constructed RuleBasedBreakIterator with the same |
|
510 |
* behavior as this one. |
|
511 |
*/ |
|
512 |
public Object clone() { |
|
513 |
RuleBasedBreakIterator result = (RuleBasedBreakIterator) super.clone(); |
|
514 |
if (text != null) { |
|
515 |
result.text = (CharacterIterator) text.clone(); |
|
516 |
} |
|
517 |
return result; |
|
518 |
} |
|
519 |
||
520 |
/** |
|
521 |
* Returns true if both BreakIterators are of the same class, have the same |
|
522 |
* rules, and iterate over the same text. |
|
523 |
*/ |
|
524 |
public boolean equals(Object that) { |
|
525 |
try { |
|
526 |
if (that == null) { |
|
527 |
return false; |
|
528 |
} |
|
529 |
||
530 |
RuleBasedBreakIterator other = (RuleBasedBreakIterator) that; |
|
531 |
if (checksum != other.checksum) { |
|
532 |
return false; |
|
533 |
} |
|
534 |
if (text == null) { |
|
535 |
return other.text == null; |
|
536 |
} else { |
|
537 |
return text.equals(other.text); |
|
538 |
} |
|
539 |
} |
|
540 |
catch(ClassCastException e) { |
|
541 |
return false; |
|
542 |
} |
|
543 |
} |
|
544 |
||
545 |
/** |
|
546 |
* Returns text |
|
547 |
*/ |
|
548 |
public String toString() { |
|
549 |
StringBuffer sb = new StringBuffer(); |
|
550 |
sb.append('['); |
|
551 |
sb.append("checksum=0x" + Long.toHexString(checksum)); |
|
552 |
sb.append(']'); |
|
553 |
return sb.toString(); |
|
554 |
} |
|
555 |
||
556 |
/** |
|
557 |
* Compute a hashcode for this BreakIterator |
|
558 |
* @return A hash code |
|
559 |
*/ |
|
560 |
public int hashCode() { |
|
561 |
return (int)checksum; |
|
562 |
} |
|
563 |
||
564 |
//======================================================================= |
|
565 |
// BreakIterator overrides |
|
566 |
//======================================================================= |
|
567 |
||
568 |
/** |
|
569 |
* Sets the current iteration position to the beginning of the text. |
|
570 |
* (i.e., the CharacterIterator's starting offset). |
|
571 |
* @return The offset of the beginning of the text. |
|
572 |
*/ |
|
573 |
public int first() { |
|
574 |
CharacterIterator t = getText(); |
|
575 |
||
576 |
t.first(); |
|
577 |
return t.getIndex(); |
|
578 |
} |
|
579 |
||
580 |
/** |
|
581 |
* Sets the current iteration position to the end of the text. |
|
582 |
* (i.e., the CharacterIterator's ending offset). |
|
583 |
* @return The text's past-the-end offset. |
|
584 |
*/ |
|
585 |
public int last() { |
|
586 |
CharacterIterator t = getText(); |
|
587 |
||
588 |
// I'm not sure why, but t.last() returns the offset of the last character, |
|
589 |
// rather than the past-the-end offset |
|
590 |
t.setIndex(t.getEndIndex()); |
|
591 |
return t.getIndex(); |
|
592 |
} |
|
593 |
||
594 |
/** |
|
595 |
* Advances the iterator either forward or backward the specified number of steps. |
|
596 |
* Negative values move backward, and positive values move forward. This is |
|
597 |
* equivalent to repeatedly calling next() or previous(). |
|
598 |
* @param n The number of steps to move. The sign indicates the direction |
|
599 |
* (negative is backwards, and positive is forwards). |
|
600 |
* @return The character offset of the boundary position n boundaries away from |
|
601 |
* the current one. |
|
602 |
*/ |
|
603 |
public int next(int n) { |
|
604 |
int result = current(); |
|
605 |
while (n > 0) { |
|
606 |
result = handleNext(); |
|
607 |
--n; |
|
608 |
} |
|
609 |
while (n < 0) { |
|
610 |
result = previous(); |
|
611 |
++n; |
|
612 |
} |
|
613 |
return result; |
|
614 |
} |
|
615 |
||
616 |
/** |
|
617 |
* Advances the iterator to the next boundary position. |
|
618 |
* @return The position of the first boundary after this one. |
|
619 |
*/ |
|
620 |
public int next() { |
|
621 |
return handleNext(); |
|
622 |
} |
|
623 |
||
4844 | 624 |
private int cachedLastKnownBreak = BreakIterator.DONE; |
625 |
||
2 | 626 |
/** |
627 |
* Advances the iterator backwards, to the last boundary preceding this one. |
|
628 |
* @return The position of the last boundary position preceding this one. |
|
629 |
*/ |
|
630 |
public int previous() { |
|
631 |
// if we're already sitting at the beginning of the text, return DONE |
|
632 |
CharacterIterator text = getText(); |
|
633 |
if (current() == text.getBeginIndex()) { |
|
634 |
return BreakIterator.DONE; |
|
635 |
} |
|
636 |
||
637 |
// set things up. handlePrevious() will back us up to some valid |
|
638 |
// break position before the current position (we back our internal |
|
639 |
// iterator up one step to prevent handlePrevious() from returning |
|
640 |
// the current position), but not necessarily the last one before |
|
641 |
// where we started |
|
642 |
int start = current(); |
|
4844 | 643 |
int lastResult = cachedLastKnownBreak; |
644 |
if (lastResult >= start || lastResult <= BreakIterator.DONE) { |
|
645 |
getPrevious(); |
|
646 |
lastResult = handlePrevious(); |
|
647 |
} else { |
|
648 |
//it might be better to check if handlePrevious() give us closer |
|
649 |
//safe value but handlePrevious() is slow too |
|
650 |
//So, this has to be done carefully |
|
651 |
text.setIndex(lastResult); |
|
652 |
} |
|
2 | 653 |
int result = lastResult; |
654 |
||
655 |
// iterate forward from the known break position until we pass our |
|
656 |
// starting point. The last break position before the starting |
|
657 |
// point is our return value |
|
658 |
while (result != BreakIterator.DONE && result < start) { |
|
659 |
lastResult = result; |
|
660 |
result = handleNext(); |
|
661 |
} |
|
662 |
||
663 |
// set the current iteration position to be the last break position |
|
664 |
// before where we started, and then return that value |
|
665 |
text.setIndex(lastResult); |
|
4844 | 666 |
cachedLastKnownBreak = lastResult; |
2 | 667 |
return lastResult; |
668 |
} |
|
669 |
||
670 |
/** |
|
671 |
* Returns previous character |
|
672 |
*/ |
|
673 |
private int getPrevious() { |
|
674 |
char c2 = text.previous(); |
|
675 |
if (Character.isLowSurrogate(c2) && |
|
676 |
text.getIndex() > text.getBeginIndex()) { |
|
677 |
char c1 = text.previous(); |
|
678 |
if (Character.isHighSurrogate(c1)) { |
|
679 |
return Character.toCodePoint(c1, c2); |
|
680 |
} else { |
|
681 |
text.next(); |
|
682 |
} |
|
683 |
} |
|
684 |
return (int)c2; |
|
685 |
} |
|
686 |
||
687 |
/** |
|
688 |
* Returns current character |
|
689 |
*/ |
|
690 |
int getCurrent() { |
|
691 |
char c1 = text.current(); |
|
692 |
if (Character.isHighSurrogate(c1) && |
|
693 |
text.getIndex() < text.getEndIndex()) { |
|
694 |
char c2 = text.next(); |
|
695 |
text.previous(); |
|
696 |
if (Character.isLowSurrogate(c2)) { |
|
697 |
return Character.toCodePoint(c1, c2); |
|
698 |
} |
|
699 |
} |
|
700 |
return (int)c1; |
|
701 |
} |
|
702 |
||
703 |
/** |
|
704 |
* Returns the count of next character. |
|
705 |
*/ |
|
706 |
private int getCurrentCodePointCount() { |
|
707 |
char c1 = text.current(); |
|
708 |
if (Character.isHighSurrogate(c1) && |
|
709 |
text.getIndex() < text.getEndIndex()) { |
|
710 |
char c2 = text.next(); |
|
711 |
text.previous(); |
|
712 |
if (Character.isLowSurrogate(c2)) { |
|
713 |
return 2; |
|
714 |
} |
|
715 |
} |
|
716 |
return 1; |
|
717 |
} |
|
718 |
||
719 |
/** |
|
720 |
* Returns next character |
|
721 |
*/ |
|
722 |
int getNext() { |
|
723 |
int index = text.getIndex(); |
|
724 |
int endIndex = text.getEndIndex(); |
|
725 |
if (index == endIndex || |
|
726 |
(index = index + getCurrentCodePointCount()) >= endIndex) { |
|
727 |
return CharacterIterator.DONE; |
|
728 |
} |
|
729 |
text.setIndex(index); |
|
730 |
return getCurrent(); |
|
731 |
} |
|
732 |
||
733 |
/** |
|
734 |
* Returns the position of next character. |
|
735 |
*/ |
|
736 |
private int getNextIndex() { |
|
737 |
int index = text.getIndex() + getCurrentCodePointCount(); |
|
738 |
int endIndex = text.getEndIndex(); |
|
739 |
if (index > endIndex) { |
|
740 |
return endIndex; |
|
741 |
} else { |
|
742 |
return index; |
|
743 |
} |
|
744 |
} |
|
745 |
||
746 |
/** |
|
747 |
* Throw IllegalArgumentException unless begin <= offset < end. |
|
748 |
*/ |
|
749 |
protected static final void checkOffset(int offset, CharacterIterator text) { |
|
750 |
if (offset < text.getBeginIndex() || offset > text.getEndIndex()) { |
|
751 |
throw new IllegalArgumentException("offset out of bounds"); |
|
752 |
} |
|
753 |
} |
|
754 |
||
755 |
/** |
|
756 |
* Sets the iterator to refer to the first boundary position following |
|
757 |
* the specified position. |
|
758 |
* @offset The position from which to begin searching for a break position. |
|
759 |
* @return The position of the first break after the current position. |
|
760 |
*/ |
|
761 |
public int following(int offset) { |
|
762 |
||
763 |
CharacterIterator text = getText(); |
|
764 |
checkOffset(offset, text); |
|
765 |
||
766 |
// Set our internal iteration position (temporarily) |
|
767 |
// to the position passed in. If this is the _beginning_ position, |
|
768 |
// then we can just use next() to get our return value |
|
769 |
text.setIndex(offset); |
|
770 |
if (offset == text.getBeginIndex()) { |
|
4844 | 771 |
cachedLastKnownBreak = handleNext(); |
772 |
return cachedLastKnownBreak; |
|
2 | 773 |
} |
774 |
||
775 |
// otherwise, we have to sync up first. Use handlePrevious() to back |
|
776 |
// us up to a known break position before the specified position (if |
|
777 |
// we can determine that the specified position is a break position, |
|
778 |
// we don't back up at all). This may or may not be the last break |
|
779 |
// position at or before our starting position. Advance forward |
|
780 |
// from here until we've passed the starting position. The position |
|
781 |
// we stop on will be the first break position after the specified one. |
|
4844 | 782 |
int result = cachedLastKnownBreak; |
783 |
if (result >= offset || result <= BreakIterator.DONE) { |
|
784 |
result = handlePrevious(); |
|
785 |
} else { |
|
786 |
//it might be better to check if handlePrevious() give us closer |
|
787 |
//safe value but handlePrevious() is slow too |
|
788 |
//So, this has to be done carefully |
|
789 |
text.setIndex(result); |
|
790 |
} |
|
2 | 791 |
while (result != BreakIterator.DONE && result <= offset) { |
792 |
result = handleNext(); |
|
793 |
} |
|
4844 | 794 |
cachedLastKnownBreak = result; |
2 | 795 |
return result; |
796 |
} |
|
797 |
||
798 |
/** |
|
799 |
* Sets the iterator to refer to the last boundary position before the |
|
800 |
* specified position. |
|
801 |
* @offset The position to begin searching for a break from. |
|
802 |
* @return The position of the last boundary before the starting position. |
|
803 |
*/ |
|
804 |
public int preceding(int offset) { |
|
805 |
// if we start by updating the current iteration position to the |
|
806 |
// position specified by the caller, we can just use previous() |
|
807 |
// to carry out this operation |
|
808 |
CharacterIterator text = getText(); |
|
809 |
checkOffset(offset, text); |
|
810 |
text.setIndex(offset); |
|
811 |
return previous(); |
|
812 |
} |
|
813 |
||
814 |
/** |
|
815 |
* Returns true if the specfied position is a boundary position. As a side |
|
816 |
* effect, leaves the iterator pointing to the first boundary position at |
|
817 |
* or after "offset". |
|
818 |
* @param offset the offset to check. |
|
819 |
* @return True if "offset" is a boundary position. |
|
820 |
*/ |
|
821 |
public boolean isBoundary(int offset) { |
|
822 |
CharacterIterator text = getText(); |
|
823 |
checkOffset(offset, text); |
|
824 |
if (offset == text.getBeginIndex()) { |
|
825 |
return true; |
|
826 |
} |
|
827 |
||
828 |
// to check whether this is a boundary, we can use following() on the |
|
829 |
// position before the specified one and return true if the position we |
|
830 |
// get back is the one the user specified |
|
831 |
else { |
|
832 |
return following(offset - 1) == offset; |
|
833 |
} |
|
834 |
} |
|
835 |
||
836 |
/** |
|
837 |
* Returns the current iteration position. |
|
838 |
* @return The current iteration position. |
|
839 |
*/ |
|
840 |
public int current() { |
|
841 |
return getText().getIndex(); |
|
842 |
} |
|
843 |
||
844 |
/** |
|
845 |
* Return a CharacterIterator over the text being analyzed. This version |
|
846 |
* of this method returns the actual CharacterIterator we're using internally. |
|
847 |
* Changing the state of this iterator can have undefined consequences. If |
|
848 |
* you need to change it, clone it first. |
|
849 |
* @return An iterator over the text being analyzed. |
|
850 |
*/ |
|
851 |
public CharacterIterator getText() { |
|
852 |
// The iterator is initialized pointing to no text at all, so if this |
|
853 |
// function is called while we're in that state, we have to fudge an |
|
854 |
// iterator to return. |
|
855 |
if (text == null) { |
|
856 |
text = new StringCharacterIterator(""); |
|
857 |
} |
|
858 |
return text; |
|
859 |
} |
|
860 |
||
861 |
/** |
|
862 |
* Set the iterator to analyze a new piece of text. This function resets |
|
863 |
* the current iteration position to the beginning of the text. |
|
864 |
* @param newText An iterator over the text to analyze. |
|
865 |
*/ |
|
866 |
public void setText(CharacterIterator newText) { |
|
867 |
// Test iterator to see if we need to wrap it in a SafeCharIterator. |
|
868 |
// The correct behavior for CharacterIterators is to allow the |
|
869 |
// position to be set to the endpoint of the iterator. Many |
|
870 |
// CharacterIterators do not uphold this, so this is a workaround |
|
871 |
// to permit them to use this class. |
|
872 |
int end = newText.getEndIndex(); |
|
873 |
boolean goodIterator; |
|
874 |
try { |
|
875 |
newText.setIndex(end); // some buggy iterators throw an exception here |
|
876 |
goodIterator = newText.getIndex() == end; |
|
877 |
} |
|
878 |
catch(IllegalArgumentException e) { |
|
879 |
goodIterator = false; |
|
880 |
} |
|
881 |
||
882 |
if (goodIterator) { |
|
883 |
text = newText; |
|
884 |
} |
|
885 |
else { |
|
886 |
text = new SafeCharIterator(newText); |
|
887 |
} |
|
888 |
text.first(); |
|
4844 | 889 |
|
890 |
cachedLastKnownBreak = BreakIterator.DONE; |
|
2 | 891 |
} |
892 |
||
893 |
||
894 |
//======================================================================= |
|
895 |
// implementation |
|
896 |
//======================================================================= |
|
897 |
||
898 |
/** |
|
899 |
* This method is the actual implementation of the next() method. All iteration |
|
900 |
* vectors through here. This method initializes the state machine to state 1 |
|
901 |
* and advances through the text character by character until we reach the end |
|
902 |
* of the text or the state machine transitions to state 0. We update our return |
|
903 |
* value every time the state machine passes through a possible end state. |
|
904 |
*/ |
|
905 |
protected int handleNext() { |
|
906 |
// if we're already at the end of the text, return DONE. |
|
907 |
CharacterIterator text = getText(); |
|
908 |
if (text.getIndex() == text.getEndIndex()) { |
|
909 |
return BreakIterator.DONE; |
|
910 |
} |
|
911 |
||
912 |
// no matter what, we always advance at least one character forward |
|
913 |
int result = getNextIndex(); |
|
914 |
int lookaheadResult = 0; |
|
915 |
||
916 |
// begin in state 1 |
|
917 |
int state = START_STATE; |
|
918 |
int category; |
|
919 |
int c = getCurrent(); |
|
920 |
||
921 |
// loop until we reach the end of the text or transition to state 0 |
|
922 |
while (c != CharacterIterator.DONE && state != STOP_STATE) { |
|
923 |
||
924 |
// look up the current character's character category (which tells us |
|
925 |
// which column in the state table to look at) |
|
926 |
category = lookupCategory(c); |
|
927 |
||
928 |
// if the character isn't an ignore character, look up a state |
|
929 |
// transition in the state table |
|
930 |
if (category != IGNORE) { |
|
931 |
state = lookupState(state, category); |
|
932 |
} |
|
933 |
||
934 |
// if the state we've just transitioned to is a lookahead state, |
|
935 |
// (but not also an end state), save its position. If it's |
|
936 |
// both a lookahead state and an end state, update the break position |
|
937 |
// to the last saved lookup-state position |
|
938 |
if (lookaheadStates[state]) { |
|
939 |
if (endStates[state]) { |
|
940 |
result = lookaheadResult; |
|
941 |
} |
|
942 |
else { |
|
943 |
lookaheadResult = getNextIndex(); |
|
944 |
} |
|
945 |
} |
|
946 |
||
947 |
// otherwise, if the state we've just transitioned to is an accepting |
|
948 |
// state, update the break position to be the current iteration position |
|
949 |
else { |
|
950 |
if (endStates[state]) { |
|
951 |
result = getNextIndex(); |
|
952 |
} |
|
953 |
} |
|
954 |
||
955 |
c = getNext(); |
|
956 |
} |
|
957 |
||
958 |
// if we've run off the end of the text, and the very last character took us into |
|
959 |
// a lookahead state, advance the break position to the lookahead position |
|
960 |
// (the theory here is that if there are no characters at all after the lookahead |
|
961 |
// position, that always matches the lookahead criteria) |
|
962 |
if (c == CharacterIterator.DONE && lookaheadResult == text.getEndIndex()) { |
|
963 |
result = lookaheadResult; |
|
964 |
} |
|
965 |
||
966 |
text.setIndex(result); |
|
967 |
return result; |
|
968 |
} |
|
969 |
||
970 |
/** |
|
971 |
* This method backs the iterator back up to a "safe position" in the text. |
|
972 |
* This is a position that we know, without any context, must be a break position. |
|
973 |
* The various calling methods then iterate forward from this safe position to |
|
974 |
* the appropriate position to return. (For more information, see the description |
|
975 |
* of buildBackwardsStateTable() in RuleBasedBreakIterator.Builder.) |
|
976 |
*/ |
|
977 |
protected int handlePrevious() { |
|
978 |
CharacterIterator text = getText(); |
|
979 |
int state = START_STATE; |
|
980 |
int category = 0; |
|
981 |
int lastCategory = 0; |
|
982 |
int c = getCurrent(); |
|
983 |
||
984 |
// loop until we reach the beginning of the text or transition to state 0 |
|
985 |
while (c != CharacterIterator.DONE && state != STOP_STATE) { |
|
986 |
||
987 |
// save the last character's category and look up the current |
|
988 |
// character's category |
|
989 |
lastCategory = category; |
|
990 |
category = lookupCategory(c); |
|
991 |
||
992 |
// if the current character isn't an ignore character, look up a |
|
993 |
// state transition in the backwards state table |
|
994 |
if (category != IGNORE) { |
|
995 |
state = lookupBackwardState(state, category); |
|
996 |
} |
|
997 |
||
998 |
// then advance one character backwards |
|
999 |
c = getPrevious(); |
|
1000 |
} |
|
1001 |
||
1002 |
// if we didn't march off the beginning of the text, we're either one or two |
|
1003 |
// positions away from the real break position. (One because of the call to |
|
1004 |
// previous() at the end of the loop above, and another because the character |
|
1005 |
// that takes us into the stop state will always be the character BEFORE |
|
1006 |
// the break position.) |
|
1007 |
if (c != CharacterIterator.DONE) { |
|
1008 |
if (lastCategory != IGNORE) { |
|
1009 |
getNext(); |
|
1010 |
getNext(); |
|
1011 |
} |
|
1012 |
else { |
|
1013 |
getNext(); |
|
1014 |
} |
|
1015 |
} |
|
1016 |
return text.getIndex(); |
|
1017 |
} |
|
1018 |
||
1019 |
/** |
|
1020 |
* Looks up a character's category (i.e., its category for breaking purposes, |
|
1021 |
* not its Unicode category) |
|
1022 |
*/ |
|
1023 |
protected int lookupCategory(int c) { |
|
1024 |
if (c < Character.MIN_SUPPLEMENTARY_CODE_POINT) { |
|
1025 |
return charCategoryTable.elementAt((char)c); |
|
1026 |
} else { |
|
1027 |
return supplementaryCharCategoryTable.getValue(c); |
|
1028 |
} |
|
1029 |
} |
|
1030 |
||
1031 |
/** |
|
1032 |
* Given a current state and a character category, looks up the |
|
1033 |
* next state to transition to in the state table. |
|
1034 |
*/ |
|
1035 |
protected int lookupState(int state, int category) { |
|
1036 |
return stateTable[state * numCategories + category]; |
|
1037 |
} |
|
1038 |
||
1039 |
/** |
|
1040 |
* Given a current state and a character category, looks up the |
|
1041 |
* next state to transition to in the backwards state table. |
|
1042 |
*/ |
|
1043 |
protected int lookupBackwardState(int state, int category) { |
|
1044 |
return backwardsStateTable[state * numCategories + category]; |
|
1045 |
} |
|
1046 |
||
1047 |
/* |
|
1048 |
* This class exists to work around a bug in incorrect implementations |
|
1049 |
* of CharacterIterator, which incorrectly handle setIndex(endIndex). |
|
1050 |
* This iterator relies only on base.setIndex(n) where n is less than |
|
1051 |
* endIndex. |
|
1052 |
* |
|
1053 |
* One caveat: if the base iterator's begin and end indices change |
|
1054 |
* the change will not be reflected by this wrapper. Does that matter? |
|
1055 |
*/ |
|
1056 |
private static final class SafeCharIterator implements CharacterIterator, |
|
1057 |
Cloneable { |
|
1058 |
||
1059 |
private CharacterIterator base; |
|
1060 |
private int rangeStart; |
|
1061 |
private int rangeLimit; |
|
1062 |
private int currentIndex; |
|
1063 |
||
1064 |
SafeCharIterator(CharacterIterator base) { |
|
1065 |
this.base = base; |
|
1066 |
this.rangeStart = base.getBeginIndex(); |
|
1067 |
this.rangeLimit = base.getEndIndex(); |
|
1068 |
this.currentIndex = base.getIndex(); |
|
1069 |
} |
|
1070 |
||
1071 |
public char first() { |
|
1072 |
return setIndex(rangeStart); |
|
1073 |
} |
|
1074 |
||
1075 |
public char last() { |
|
1076 |
return setIndex(rangeLimit - 1); |
|
1077 |
} |
|
1078 |
||
1079 |
public char current() { |
|
1080 |
if (currentIndex < rangeStart || currentIndex >= rangeLimit) { |
|
1081 |
return DONE; |
|
1082 |
} |
|
1083 |
else { |
|
1084 |
return base.setIndex(currentIndex); |
|
1085 |
} |
|
1086 |
} |
|
1087 |
||
1088 |
public char next() { |
|
1089 |
||
1090 |
currentIndex++; |
|
1091 |
if (currentIndex >= rangeLimit) { |
|
1092 |
currentIndex = rangeLimit; |
|
1093 |
return DONE; |
|
1094 |
} |
|
1095 |
else { |
|
1096 |
return base.setIndex(currentIndex); |
|
1097 |
} |
|
1098 |
} |
|
1099 |
||
1100 |
public char previous() { |
|
1101 |
||
1102 |
currentIndex--; |
|
1103 |
if (currentIndex < rangeStart) { |
|
1104 |
currentIndex = rangeStart; |
|
1105 |
return DONE; |
|
1106 |
} |
|
1107 |
else { |
|
1108 |
return base.setIndex(currentIndex); |
|
1109 |
} |
|
1110 |
} |
|
1111 |
||
1112 |
public char setIndex(int i) { |
|
1113 |
||
1114 |
if (i < rangeStart || i > rangeLimit) { |
|
1115 |
throw new IllegalArgumentException("Invalid position"); |
|
1116 |
} |
|
1117 |
currentIndex = i; |
|
1118 |
return current(); |
|
1119 |
} |
|
1120 |
||
1121 |
public int getBeginIndex() { |
|
1122 |
return rangeStart; |
|
1123 |
} |
|
1124 |
||
1125 |
public int getEndIndex() { |
|
1126 |
return rangeLimit; |
|
1127 |
} |
|
1128 |
||
1129 |
public int getIndex() { |
|
1130 |
return currentIndex; |
|
1131 |
} |
|
1132 |
||
1133 |
public Object clone() { |
|
1134 |
||
1135 |
SafeCharIterator copy = null; |
|
1136 |
try { |
|
1137 |
copy = (SafeCharIterator) super.clone(); |
|
1138 |
} |
|
1139 |
catch(CloneNotSupportedException e) { |
|
1140 |
throw new Error("Clone not supported: " + e); |
|
1141 |
} |
|
1142 |
||
1143 |
CharacterIterator copyOfBase = (CharacterIterator) base.clone(); |
|
1144 |
copy.base = copyOfBase; |
|
1145 |
return copy; |
|
1146 |
} |
|
1147 |
} |
|
1148 |
} |