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1144 lines
42 KiB
Java
1144 lines
42 KiB
Java
/*
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* Copyright (c) 1999, 2016, 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 sun.text;
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import java.nio.BufferUnderflowException;
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import java.nio.ByteBuffer;
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import java.text.BreakIterator;
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import java.text.CharacterIterator;
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import java.text.StringCharacterIterator;
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import java.util.MissingResourceException;
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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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public 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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* 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 using the given rule data.
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*
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* @throws MissingResourceException if the rule data is invalid or corrupted
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*/
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public RuleBasedBreakIterator(String ruleFile, byte[] ruleData) {
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ByteBuffer bb = ByteBuffer.wrap(ruleData);
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try {
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validateRuleData(ruleFile, bb);
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setupTables(ruleFile, bb);
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} catch (BufferUnderflowException bue) {
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MissingResourceException e;
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e = new MissingResourceException("Corrupted rule data file", ruleFile, "");
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e.initCause(bue);
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throw e;
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}
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}
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/**
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* Initializes the fields with the given rule data.
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* The data 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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* @throws BufferUnderflowException if the end-of-data is reached before
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* setting up all the tables
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*/
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private void setupTables(String ruleFile, ByteBuffer bb) {
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/* Read header_info. */
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int stateTableLength = bb.getInt();
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int backwardsStateTableLength = bb.getInt();
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int endStatesLength = bb.getInt();
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int lookaheadStatesLength = bb.getInt();
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int BMPdataLength = bb.getInt();
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int nonBMPdataLength = bb.getInt();
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int additionalDataLength = bb.getInt();
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checksum = bb.getLong();
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/* Read stateTable[numCategories * numRows] */
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stateTable = new short[stateTableLength];
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for (int i = 0; i < stateTableLength; i++) {
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stateTable[i] = bb.getShort();
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}
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/* Read backwardsStateTable[numCategories * numRows] */
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backwardsStateTable = new short[backwardsStateTableLength];
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for (int i = 0; i < backwardsStateTableLength; i++) {
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backwardsStateTable[i] = bb.getShort();
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}
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/* Read endStates[numRows] */
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endStates = new boolean[endStatesLength];
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for (int i = 0; i < endStatesLength; i++) {
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endStates[i] = bb.get() == 1;
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}
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/* Read lookaheadStates[numRows] */
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lookaheadStates = new boolean[lookaheadStatesLength];
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for (int i = 0; i < lookaheadStatesLength; i++) {
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lookaheadStates[i] = bb.get() == 1;
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}
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/* Read a category table and indices for BMP characters. */
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short[] temp1 = new short[BMP_INDICES_LENGTH]; // BMPindices
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for (int i = 0; i < BMP_INDICES_LENGTH; i++) {
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temp1[i] = bb.getShort();
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}
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byte[] temp2 = new byte[BMPdataLength]; // BMPdata
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bb.get(temp2);
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charCategoryTable = new CompactByteArray(temp1, temp2);
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/* Read a category table for non-BMP characters. */
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int[] temp3 = new int[nonBMPdataLength];
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for (int i = 0; i < nonBMPdataLength; i++) {
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temp3[i] = bb.getInt();
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}
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supplementaryCharCategoryTable = new SupplementaryCharacterData(temp3);
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/* Read additional data */
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if (additionalDataLength > 0) {
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additionalData = new byte[additionalDataLength];
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bb.get(additionalData);
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}
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assert bb.position() == bb.limit();
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/* Set numCategories */
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numCategories = stateTable.length / endStates.length;
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}
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/**
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* Validates the magic number, version, and the length of the given data.
|
|
*
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* @throws BufferUnderflowException if the end-of-data is reached while
|
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* validating data
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* @throws MissingResourceException if valification failed
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*/
|
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void validateRuleData(String ruleFile, ByteBuffer bb) {
|
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/* Verify the magic number. */
|
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for (int i = 0; i < LABEL_LENGTH; i++) {
|
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if (bb.get() != LABEL[i]) {
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throw new MissingResourceException("Wrong magic number",
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ruleFile, "");
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}
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}
|
|
|
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/* Verify the version number. */
|
|
byte version = bb.get();
|
|
if (version != supportedVersion) {
|
|
throw new MissingResourceException("Unsupported version(" + version + ")",
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ruleFile, "");
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}
|
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|
|
// Check the length of the rest of data
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|
int len = bb.getInt();
|
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if (bb.position() + len != bb.limit()) {
|
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throw new MissingResourceException("Wrong data length",
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ruleFile, "");
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}
|
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}
|
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|
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byte[] getAdditionalData() {
|
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return additionalData;
|
|
}
|
|
|
|
void setAdditionalData(byte[] b) {
|
|
additionalData = b;
|
|
}
|
|
|
|
//=======================================================================
|
|
// boilerplate
|
|
//=======================================================================
|
|
/**
|
|
* Clones this iterator.
|
|
* @return A newly-constructed RuleBasedBreakIterator with the same
|
|
* behavior as this one.
|
|
*/
|
|
@Override
|
|
public Object clone() {
|
|
RuleBasedBreakIterator result = (RuleBasedBreakIterator) super.clone();
|
|
if (text != null) {
|
|
result.text = (CharacterIterator) text.clone();
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Returns true if both BreakIterators are of the same class, have the same
|
|
* rules, and iterate over the same text.
|
|
*/
|
|
@Override
|
|
public boolean equals(Object that) {
|
|
try {
|
|
if (that == null) {
|
|
return false;
|
|
}
|
|
|
|
RuleBasedBreakIterator other = (RuleBasedBreakIterator) that;
|
|
if (checksum != other.checksum) {
|
|
return false;
|
|
}
|
|
if (text == null) {
|
|
return other.text == null;
|
|
} else {
|
|
return text.equals(other.text);
|
|
}
|
|
}
|
|
catch(ClassCastException e) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns text
|
|
*/
|
|
@Override
|
|
public String toString() {
|
|
return "[checksum=0x" + Long.toHexString(checksum) + ']';
|
|
}
|
|
|
|
/**
|
|
* Compute a hashcode for this BreakIterator
|
|
* @return A hash code
|
|
*/
|
|
@Override
|
|
public int hashCode() {
|
|
return (int)checksum;
|
|
}
|
|
|
|
//=======================================================================
|
|
// BreakIterator overrides
|
|
//=======================================================================
|
|
|
|
/**
|
|
* Sets the current iteration position to the beginning of the text.
|
|
* (i.e., the CharacterIterator's starting offset).
|
|
* @return The offset of the beginning of the text.
|
|
*/
|
|
@Override
|
|
public int first() {
|
|
CharacterIterator t = getText();
|
|
|
|
t.first();
|
|
return t.getIndex();
|
|
}
|
|
|
|
/**
|
|
* Sets the current iteration position to the end of the text.
|
|
* (i.e., the CharacterIterator's ending offset).
|
|
* @return The text's past-the-end offset.
|
|
*/
|
|
@Override
|
|
public int last() {
|
|
CharacterIterator t = getText();
|
|
|
|
// I'm not sure why, but t.last() returns the offset of the last character,
|
|
// rather than the past-the-end offset
|
|
t.setIndex(t.getEndIndex());
|
|
return t.getIndex();
|
|
}
|
|
|
|
/**
|
|
* Advances the iterator either forward or backward the specified number of steps.
|
|
* Negative values move backward, and positive values move forward. This is
|
|
* equivalent to repeatedly calling next() or previous().
|
|
* @param n The number of steps to move. The sign indicates the direction
|
|
* (negative is backwards, and positive is forwards).
|
|
* @return The character offset of the boundary position n boundaries away from
|
|
* the current one.
|
|
*/
|
|
@Override
|
|
public int next(int n) {
|
|
int result = current();
|
|
while (n > 0) {
|
|
result = handleNext();
|
|
--n;
|
|
}
|
|
while (n < 0) {
|
|
result = previous();
|
|
++n;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Advances the iterator to the next boundary position.
|
|
* @return The position of the first boundary after this one.
|
|
*/
|
|
@Override
|
|
public int next() {
|
|
return handleNext();
|
|
}
|
|
|
|
private int cachedLastKnownBreak = BreakIterator.DONE;
|
|
|
|
/**
|
|
* Advances the iterator backwards, to the last boundary preceding this one.
|
|
* @return The position of the last boundary position preceding this one.
|
|
*/
|
|
@Override
|
|
public int previous() {
|
|
// if we're already sitting at the beginning of the text, return DONE
|
|
CharacterIterator text = getText();
|
|
if (current() == text.getBeginIndex()) {
|
|
return BreakIterator.DONE;
|
|
}
|
|
|
|
// set things up. handlePrevious() will back us up to some valid
|
|
// break position before the current position (we back our internal
|
|
// iterator up one step to prevent handlePrevious() from returning
|
|
// the current position), but not necessarily the last one before
|
|
// where we started
|
|
int start = current();
|
|
int lastResult = cachedLastKnownBreak;
|
|
if (lastResult >= start || lastResult <= BreakIterator.DONE) {
|
|
getPrevious();
|
|
lastResult = handlePrevious();
|
|
} else {
|
|
//it might be better to check if handlePrevious() give us closer
|
|
//safe value but handlePrevious() is slow too
|
|
//So, this has to be done carefully
|
|
text.setIndex(lastResult);
|
|
}
|
|
int result = lastResult;
|
|
|
|
// iterate forward from the known break position until we pass our
|
|
// starting point. The last break position before the starting
|
|
// point is our return value
|
|
while (result != BreakIterator.DONE && result < start) {
|
|
lastResult = result;
|
|
result = handleNext();
|
|
}
|
|
|
|
// set the current iteration position to be the last break position
|
|
// before where we started, and then return that value
|
|
text.setIndex(lastResult);
|
|
cachedLastKnownBreak = lastResult;
|
|
return lastResult;
|
|
}
|
|
|
|
/**
|
|
* Returns previous character
|
|
*/
|
|
private int getPrevious() {
|
|
char c2 = text.previous();
|
|
if (Character.isLowSurrogate(c2) &&
|
|
text.getIndex() > text.getBeginIndex()) {
|
|
char c1 = text.previous();
|
|
if (Character.isHighSurrogate(c1)) {
|
|
return Character.toCodePoint(c1, c2);
|
|
} else {
|
|
text.next();
|
|
}
|
|
}
|
|
return (int)c2;
|
|
}
|
|
|
|
/**
|
|
* Returns current character
|
|
*/
|
|
int getCurrent() {
|
|
char c1 = text.current();
|
|
if (Character.isHighSurrogate(c1) &&
|
|
text.getIndex() < text.getEndIndex()) {
|
|
char c2 = text.next();
|
|
text.previous();
|
|
if (Character.isLowSurrogate(c2)) {
|
|
return Character.toCodePoint(c1, c2);
|
|
}
|
|
}
|
|
return (int)c1;
|
|
}
|
|
|
|
/**
|
|
* Returns the count of next character.
|
|
*/
|
|
private int getCurrentCodePointCount() {
|
|
char c1 = text.current();
|
|
if (Character.isHighSurrogate(c1) &&
|
|
text.getIndex() < text.getEndIndex()) {
|
|
char c2 = text.next();
|
|
text.previous();
|
|
if (Character.isLowSurrogate(c2)) {
|
|
return 2;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* Returns next character
|
|
*/
|
|
int getNext() {
|
|
int index = text.getIndex();
|
|
int endIndex = text.getEndIndex();
|
|
if (index == endIndex ||
|
|
(index += getCurrentCodePointCount()) >= endIndex) {
|
|
return CharacterIterator.DONE;
|
|
}
|
|
text.setIndex(index);
|
|
return getCurrent();
|
|
}
|
|
|
|
/**
|
|
* Returns the position of next character.
|
|
*/
|
|
private int getNextIndex() {
|
|
int index = text.getIndex() + getCurrentCodePointCount();
|
|
int endIndex = text.getEndIndex();
|
|
if (index > endIndex) {
|
|
return endIndex;
|
|
} else {
|
|
return index;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Throw IllegalArgumentException unless begin <= offset < end.
|
|
*/
|
|
protected static final void checkOffset(int offset, CharacterIterator text) {
|
|
if (offset < text.getBeginIndex() || offset > text.getEndIndex()) {
|
|
throw new IllegalArgumentException("offset out of bounds");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Sets the iterator to refer to the first boundary position following
|
|
* the specified position.
|
|
* @offset The position from which to begin searching for a break position.
|
|
* @return The position of the first break after the current position.
|
|
*/
|
|
@Override
|
|
public int following(int offset) {
|
|
|
|
CharacterIterator text = getText();
|
|
checkOffset(offset, text);
|
|
|
|
// Set our internal iteration position (temporarily)
|
|
// to the position passed in. If this is the _beginning_ position,
|
|
// then we can just use next() to get our return value
|
|
text.setIndex(offset);
|
|
if (offset == text.getBeginIndex()) {
|
|
cachedLastKnownBreak = handleNext();
|
|
return cachedLastKnownBreak;
|
|
}
|
|
|
|
// otherwise, we have to sync up first. Use handlePrevious() to back
|
|
// us up to a known break position before the specified position (if
|
|
// we can determine that the specified position is a break position,
|
|
// we don't back up at all). This may or may not be the last break
|
|
// position at or before our starting position. Advance forward
|
|
// from here until we've passed the starting position. The position
|
|
// we stop on will be the first break position after the specified one.
|
|
int result = cachedLastKnownBreak;
|
|
if (result >= offset || result <= BreakIterator.DONE) {
|
|
result = handlePrevious();
|
|
} else {
|
|
//it might be better to check if handlePrevious() give us closer
|
|
//safe value but handlePrevious() is slow too
|
|
//So, this has to be done carefully
|
|
text.setIndex(result);
|
|
}
|
|
while (result != BreakIterator.DONE && result <= offset) {
|
|
result = handleNext();
|
|
}
|
|
cachedLastKnownBreak = result;
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Sets the iterator to refer to the last boundary position before the
|
|
* specified position.
|
|
* @offset The position to begin searching for a break from.
|
|
* @return The position of the last boundary before the starting position.
|
|
*/
|
|
@Override
|
|
public int preceding(int offset) {
|
|
// if we start by updating the current iteration position to the
|
|
// position specified by the caller, we can just use previous()
|
|
// to carry out this operation
|
|
CharacterIterator text = getText();
|
|
checkOffset(offset, text);
|
|
text.setIndex(offset);
|
|
return previous();
|
|
}
|
|
|
|
/**
|
|
* Returns true if the specified position is a boundary position. As a side
|
|
* effect, leaves the iterator pointing to the first boundary position at
|
|
* or after "offset".
|
|
* @param offset the offset to check.
|
|
* @return True if "offset" is a boundary position.
|
|
*/
|
|
@Override
|
|
public boolean isBoundary(int offset) {
|
|
CharacterIterator text = getText();
|
|
checkOffset(offset, text);
|
|
if (offset == text.getBeginIndex()) {
|
|
return true;
|
|
}
|
|
|
|
// to check whether this is a boundary, we can use following() on the
|
|
// position before the specified one and return true if the position we
|
|
// get back is the one the user specified
|
|
else {
|
|
return following(offset - 1) == offset;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns the current iteration position.
|
|
* @return The current iteration position.
|
|
*/
|
|
@Override
|
|
public int current() {
|
|
return getText().getIndex();
|
|
}
|
|
|
|
/**
|
|
* Return a CharacterIterator over the text being analyzed. This version
|
|
* of this method returns the actual CharacterIterator we're using internally.
|
|
* Changing the state of this iterator can have undefined consequences. If
|
|
* you need to change it, clone it first.
|
|
* @return An iterator over the text being analyzed.
|
|
*/
|
|
@Override
|
|
public CharacterIterator getText() {
|
|
// The iterator is initialized pointing to no text at all, so if this
|
|
// function is called while we're in that state, we have to fudge an
|
|
// iterator to return.
|
|
if (text == null) {
|
|
text = new StringCharacterIterator("");
|
|
}
|
|
return text;
|
|
}
|
|
|
|
/**
|
|
* Set the iterator to analyze a new piece of text. This function resets
|
|
* the current iteration position to the beginning of the text.
|
|
* @param newText An iterator over the text to analyze.
|
|
*/
|
|
@Override
|
|
public void setText(CharacterIterator newText) {
|
|
// Test iterator to see if we need to wrap it in a SafeCharIterator.
|
|
// The correct behavior for CharacterIterators is to allow the
|
|
// position to be set to the endpoint of the iterator. Many
|
|
// CharacterIterators do not uphold this, so this is a workaround
|
|
// to permit them to use this class.
|
|
int end = newText.getEndIndex();
|
|
boolean goodIterator;
|
|
try {
|
|
newText.setIndex(end); // some buggy iterators throw an exception here
|
|
goodIterator = newText.getIndex() == end;
|
|
}
|
|
catch(IllegalArgumentException e) {
|
|
goodIterator = false;
|
|
}
|
|
|
|
if (goodIterator) {
|
|
text = newText;
|
|
}
|
|
else {
|
|
text = new SafeCharIterator(newText);
|
|
}
|
|
text.first();
|
|
|
|
cachedLastKnownBreak = BreakIterator.DONE;
|
|
}
|
|
|
|
|
|
//=======================================================================
|
|
// implementation
|
|
//=======================================================================
|
|
|
|
/**
|
|
* This method is the actual implementation of the next() method. All iteration
|
|
* vectors through here. This method initializes the state machine to state 1
|
|
* and advances through the text character by character until we reach the end
|
|
* of the text or the state machine transitions to state 0. We update our return
|
|
* value every time the state machine passes through a possible end state.
|
|
*/
|
|
protected int handleNext() {
|
|
// if we're already at the end of the text, return DONE.
|
|
CharacterIterator text = getText();
|
|
if (text.getIndex() == text.getEndIndex()) {
|
|
return BreakIterator.DONE;
|
|
}
|
|
|
|
// no matter what, we always advance at least one character forward
|
|
int result = getNextIndex();
|
|
int lookaheadResult = 0;
|
|
|
|
// begin in state 1
|
|
int state = START_STATE;
|
|
int category;
|
|
int c = getCurrent();
|
|
|
|
// loop until we reach the end of the text or transition to state 0
|
|
while (c != CharacterIterator.DONE && state != STOP_STATE) {
|
|
|
|
// look up the current character's character category (which tells us
|
|
// which column in the state table to look at)
|
|
category = lookupCategory(c);
|
|
|
|
// if the character isn't an ignore character, look up a state
|
|
// transition in the state table
|
|
if (category != IGNORE) {
|
|
state = lookupState(state, category);
|
|
}
|
|
|
|
// if the state we've just transitioned to is a lookahead state,
|
|
// (but not also an end state), save its position. If it's
|
|
// both a lookahead state and an end state, update the break position
|
|
// to the last saved lookup-state position
|
|
if (lookaheadStates[state]) {
|
|
if (endStates[state]) {
|
|
result = lookaheadResult;
|
|
}
|
|
else {
|
|
lookaheadResult = getNextIndex();
|
|
}
|
|
}
|
|
|
|
// otherwise, if the state we've just transitioned to is an accepting
|
|
// state, update the break position to be the current iteration position
|
|
else {
|
|
if (endStates[state]) {
|
|
result = getNextIndex();
|
|
}
|
|
}
|
|
|
|
c = getNext();
|
|
}
|
|
|
|
// if we've run off the end of the text, and the very last character took us into
|
|
// a lookahead state, advance the break position to the lookahead position
|
|
// (the theory here is that if there are no characters at all after the lookahead
|
|
// position, that always matches the lookahead criteria)
|
|
if (c == CharacterIterator.DONE && lookaheadResult == text.getEndIndex()) {
|
|
result = lookaheadResult;
|
|
}
|
|
|
|
text.setIndex(result);
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* This method backs the iterator back up to a "safe position" in the text.
|
|
* This is a position that we know, without any context, must be a break position.
|
|
* The various calling methods then iterate forward from this safe position to
|
|
* the appropriate position to return. (For more information, see the description
|
|
* of buildBackwardsStateTable() in RuleBasedBreakIterator.Builder.)
|
|
*/
|
|
protected int handlePrevious() {
|
|
CharacterIterator text = getText();
|
|
int state = START_STATE;
|
|
int category = 0;
|
|
int lastCategory = 0;
|
|
int c = getCurrent();
|
|
|
|
// loop until we reach the beginning of the text or transition to state 0
|
|
while (c != CharacterIterator.DONE && state != STOP_STATE) {
|
|
|
|
// save the last character's category and look up the current
|
|
// character's category
|
|
lastCategory = category;
|
|
category = lookupCategory(c);
|
|
|
|
// if the current character isn't an ignore character, look up a
|
|
// state transition in the backwards state table
|
|
if (category != IGNORE) {
|
|
state = lookupBackwardState(state, category);
|
|
}
|
|
|
|
// then advance one character backwards
|
|
c = getPrevious();
|
|
}
|
|
|
|
// if we didn't march off the beginning of the text, we're either one or two
|
|
// positions away from the real break position. (One because of the call to
|
|
// previous() at the end of the loop above, and another because the character
|
|
// that takes us into the stop state will always be the character BEFORE
|
|
// the break position.)
|
|
if (c != CharacterIterator.DONE) {
|
|
if (lastCategory != IGNORE) {
|
|
getNext();
|
|
getNext();
|
|
}
|
|
else {
|
|
getNext();
|
|
}
|
|
}
|
|
return text.getIndex();
|
|
}
|
|
|
|
/**
|
|
* Looks up a character's category (i.e., its category for breaking purposes,
|
|
* not its Unicode category)
|
|
*/
|
|
protected int lookupCategory(int c) {
|
|
if (c < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
|
|
return charCategoryTable.elementAt((char)c);
|
|
} else {
|
|
return supplementaryCharCategoryTable.getValue(c);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Given a current state and a character category, looks up the
|
|
* next state to transition to in the state table.
|
|
*/
|
|
protected int lookupState(int state, int category) {
|
|
return stateTable[state * numCategories + category];
|
|
}
|
|
|
|
/**
|
|
* Given a current state and a character category, looks up the
|
|
* next state to transition to in the backwards state table.
|
|
*/
|
|
protected int lookupBackwardState(int state, int category) {
|
|
return backwardsStateTable[state * numCategories + category];
|
|
}
|
|
|
|
/*
|
|
* This class exists to work around a bug in incorrect implementations
|
|
* of CharacterIterator, which incorrectly handle setIndex(endIndex).
|
|
* This iterator relies only on base.setIndex(n) where n is less than
|
|
* endIndex.
|
|
*
|
|
* One caveat: if the base iterator's begin and end indices change
|
|
* the change will not be reflected by this wrapper. Does that matter?
|
|
*/
|
|
// TODO: Review this class to see if it's still required.
|
|
private static final class SafeCharIterator implements CharacterIterator,
|
|
Cloneable {
|
|
|
|
private CharacterIterator base;
|
|
private int rangeStart;
|
|
private int rangeLimit;
|
|
private int currentIndex;
|
|
|
|
SafeCharIterator(CharacterIterator base) {
|
|
this.base = base;
|
|
this.rangeStart = base.getBeginIndex();
|
|
this.rangeLimit = base.getEndIndex();
|
|
this.currentIndex = base.getIndex();
|
|
}
|
|
|
|
@Override
|
|
public char first() {
|
|
return setIndex(rangeStart);
|
|
}
|
|
|
|
@Override
|
|
public char last() {
|
|
return setIndex(rangeLimit - 1);
|
|
}
|
|
|
|
@Override
|
|
public char current() {
|
|
if (currentIndex < rangeStart || currentIndex >= rangeLimit) {
|
|
return DONE;
|
|
}
|
|
else {
|
|
return base.setIndex(currentIndex);
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public char next() {
|
|
|
|
currentIndex++;
|
|
if (currentIndex >= rangeLimit) {
|
|
currentIndex = rangeLimit;
|
|
return DONE;
|
|
}
|
|
else {
|
|
return base.setIndex(currentIndex);
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public char previous() {
|
|
|
|
currentIndex--;
|
|
if (currentIndex < rangeStart) {
|
|
currentIndex = rangeStart;
|
|
return DONE;
|
|
}
|
|
else {
|
|
return base.setIndex(currentIndex);
|
|
}
|
|
}
|
|
|
|
@Override
|
|
public char setIndex(int i) {
|
|
|
|
if (i < rangeStart || i > rangeLimit) {
|
|
throw new IllegalArgumentException("Invalid position");
|
|
}
|
|
currentIndex = i;
|
|
return current();
|
|
}
|
|
|
|
@Override
|
|
public int getBeginIndex() {
|
|
return rangeStart;
|
|
}
|
|
|
|
@Override
|
|
public int getEndIndex() {
|
|
return rangeLimit;
|
|
}
|
|
|
|
@Override
|
|
public int getIndex() {
|
|
return currentIndex;
|
|
}
|
|
|
|
@Override
|
|
public Object clone() {
|
|
|
|
SafeCharIterator copy = null;
|
|
try {
|
|
copy = (SafeCharIterator) super.clone();
|
|
}
|
|
catch(CloneNotSupportedException e) {
|
|
throw new Error("Clone not supported: " + e);
|
|
}
|
|
|
|
CharacterIterator copyOfBase = (CharacterIterator) base.clone();
|
|
copy.base = copyOfBase;
|
|
return copy;
|
|
}
|
|
}
|
|
}
|