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	/*
	* Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	*
	* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
	* (C) Copyright IBM Corp. 1996 - 2002 - All Rights Reserved
	*
	* The original version of this source code and documentation
	* is copyrighted and owned by Taligent, Inc., a wholly-owned
	* subsidiary of IBM. These materials are provided under terms
	* of a License Agreement between Taligent and Sun. This technology
	* is protected by multiple US and International patents.
	*
	* This notice and attribution to Taligent may not be removed.
	* Taligent is a registered trademark of Taligent, Inc.
	*/

	package sun.text;

	import java.nio.BufferUnderflowException;
	import java.nio.ByteBuffer;
	import java.text.BreakIterator;
	import java.text.CharacterIterator;
	import java.text.StringCharacterIterator;
	import java.util.MissingResourceException;
	import sun.text.CompactByteArray;
	import sun.text.SupplementaryCharacterData;

	/**
	* <p>A subclass of BreakIterator whose behavior is specified using a list of rules.</p>
	*
	* <p>There are two kinds of rules, which are separated by semicolons: <i>substitutions</i>
	* and <i>regular expressions.</i></p>
	*
	* <p>A substitution rule defines a name that can be used in place of an expression. It
	* consists of a name, which is a string of characters contained in angle brackets, an equals
	* sign, and an expression. (There can be no whitespace on either side of the equals sign.)
	* To keep its syntactic meaning intact, the expression must be enclosed in parentheses or
	* square brackets. A substitution is visible after its definition, and is filled in using
	* simple textual substitution. Substitution definitions can contain other substitutions, as
	* long as those substitutions have been defined first. Substitutions are generally used to
	* make the regular expressions (which can get quite complex) shorted and easier to read.
	* They typically define either character categories or commonly-used subexpressions.</p>
	*
	* <p>There is one special substitution.  If the description defines a substitution
	* called "<ignore>", the expression must be a [] expression, and the
	* expression defines a set of characters (the "<em>ignore characters</em>") that
	* will be transparent to the BreakIterator.  A sequence of characters will break the
	* same way it would if any ignore characters it contains are taken out.  Break
	* positions never occur befoer ignore characters.</p>
	*
	* <p>A regular expression uses a subset of the normal Unix regular-expression syntax, and
	* defines a sequence of characters to be kept together. With one significant exception, the
	* iterator uses a longest-possible-match algorithm when matching text to regular
	* expressions. The iterator also treats descriptions containing multiple regular expressions
	* as if they were ORed together (i.e., as if they were separated by \|).</p>
	*
	* <p>The special characters recognized by the regular-expression parser are as follows:</p>
	*
	* <blockquote>
	* <table border="1" width="100%">
	* <tr>
	* <td width="6%">*</td>
	* <td width="94%">Specifies that the expression preceding the asterisk may occur any number
	* of times (including not at all).</td>
	* </tr>
	* <tr>
	* <td width="6%">{}</td>
	* <td width="94%">Encloses a sequence of characters that is optional.</td>
	* </tr>
	* <tr>
	* <td width="6%">()</td>
	* <td width="94%">Encloses a sequence of characters.  If followed by *, the sequence
	* repeats.  Otherwise, the parentheses are just a grouping device and a way to delimit
	* the ends of expressions containing \|.</td>
	* </tr>
	* <tr>
	* <td width="6%">\|</td>
	* <td width="94%">Separates two alternative sequences of characters.  Either one
	* sequence or the other, but not both, matches this expression.  The \| character can
	* only occur inside ().</td>
	* </tr>
	* <tr>
	* <td width="6%">.</td>
	* <td width="94%">Matches any character.</td>
	* </tr>
	* <tr>
	* <td width="6%">*?</td>
	* <td width="94%">Specifies a non-greedy asterisk.  ? works the same way as , except
	* when there is overlap between the last group of characters in the expression preceding the
	* * and the first group of characters following the *.  When there is this kind of
	* overlap, * will match the longest sequence of characters that match the expression before
	* the , and ? will match the shortest sequence of characters matching the expression
	* before the *?.  For example, if you have "xxyxyyyxyxyxxyxyxyy" in the text,
	* "x[xy]*x" will match through to the last x (i.e., "<strong>xxyxyyyxyxyxxyxyx</strong>yy",
	* but "x[xy]*?x" will only match the first two xes ("<strong>xx</strong>yxyyyxyxyxxyxyxyy").</td>
	* </tr>
	* <tr>
	* <td width="6%">[]</td>
	* <td width="94%">Specifies a group of alternative characters.  A [] expression will
	* match any single character that is specified in the [] expression.  For more on the
	* syntax of [] expressions, see below.</td>
	* </tr>
	* <tr>
	* <td width="6%">/</td>
	* <td width="94%">Specifies where the break position should go if text matches this
	* expression.  (e.g., "[a-z]/[:Zs:][1-0]" will match if the iterator sees a run
	* of letters, followed by a run of whitespace, followed by a digit, but the break position
	* will actually go before the whitespace).  Expressions that don't contain / put the
	* break position at the end of the matching text.</td>
	* </tr>
	* <tr>
	* <td width="6%">\</td>
	* <td width="94%">Escape character.  The \ itself is ignored, but causes the next
	* character to be treated as literal character.  This has no effect for many
	* characters, but for the characters listed above, this deprives them of their special
	* meaning.  (There are no special escape sequences for Unicode characters, or tabs and
	* newlines; these are all handled by a higher-level protocol.  In a Java string,
	* "\n" will be converted to a literal newline character by the time the
	* regular-expression parser sees it.  Of course, this means that \ sequences that are
	* visible to the regexp parser must be written as \\ when inside a Java string.)  All
	* characters in the ASCII range except for letters, digits, and control characters are
	* reserved characters to the parser and must be preceded by \ even if they currently don't
	* mean anything.</td>
	* </tr>
	* <tr>
	* <td width="6%">!</td>
	* <td width="94%">If ! appears at the beginning of a regular expression, it tells the regexp
	* parser that this expression specifies the backwards-iteration behavior of the iterator,
	* and not its normal iteration behavior.  This is generally only used in situations
	* where the automatically-generated backwards-iteration brhavior doesn't produce
	* satisfactory results and must be supplemented with extra client-specified rules.</td>
	* </tr>
	* <tr>
	* <td width="6%"><em>(all others)</em></td>
	* <td width="94%">All other characters are treated as literal characters, which must match
	* the corresponding character(s) in the text exactly.</td>
	* </tr>
	* </table>
	* </blockquote>
	*
	* <p>Within a [] expression, a number of other special characters can be used to specify
	* groups of characters:</p>
	*
	* <blockquote>
	* <table border="1" width="100%">
	* <tr>
	* <td width="6%">-</td>
	* <td width="94%">Specifies a range of matching characters.  For example
	* "[a-p]" matches all lowercase Latin letters from a to p (inclusive).  The -
	* sign specifies ranges of continuous Unicode numeric values, not ranges of characters in a
	* language's alphabetical order: "[a-z]" doesn't include capital letters, nor does
	* it include accented letters such as a-umlaut.</td>
	* </tr>
	* <tr>
	* <td width="6%">::</td>
	* <td width="94%">A pair of colons containing a one- or two-letter code matches all
	* characters in the corresponding Unicode category.  The two-letter codes are the same
	* as the two-letter codes in the Unicode database (for example, "[:Sc::Sm:]"
	* matches all currency symbols and all math symbols).  Specifying a one-letter code is
	* the same as specifying all two-letter codes that begin with that letter (for example,
	* "[:L:]" matches all letters, and is equivalent to
	* "[:Lu::Ll::Lo::Lm::Lt:]").  Anything other than a valid two-letter Unicode
	* category code or a single letter that begins a Unicode category code is illegal within
	* colons.</td>
	* </tr>
	* <tr>
	* <td width="6%">[]</td>
	* <td width="94%">[] expressions can nest.  This has no effect, except when used in
	* conjunction with the ^ token.</td>
	* </tr>
	* <tr>
	* <td width="6%">^</td>
	* <td width="94%">Excludes the character (or the characters in the [] expression) following
	* it from the group of characters.  For example, "[a-z^p]" matches all Latin
	* lowercase letters except p.  "[:L:^[\u4e00-\u9fff]]" matches all letters
	* except the Han ideographs.</td>
	* </tr>
	* <tr>
	* <td width="6%"><em>(all others)</em></td>
	* <td width="94%">All other characters are treated as literal characters.  (For
	* example, "[aeiou]" specifies just the letters a, e, i, o, and u.)</td>
	* </tr>
	* </table>
	* </blockquote>
	*
	* <p>For a more complete explanation, see <a
	* href="http://www.ibm.com/java/education/boundaries/boundaries.html">http://www.ibm.com/java/education/boundaries/boundaries.html</a>.
	*   For examples, see the resource data (which is annotated).</p>
	*
	* @author Richard Gillam
	*/
	public class RuleBasedBreakIterator extends BreakIterator {

	/**
	* A token used as a character-category value to identify ignore characters
	*/
	protected static final byte IGNORE = -1;

	/**
	* The state number of the starting state
	*/
	private static final short START_STATE = 1;

	/**
	* The state-transition value indicating "stop"
	*/
	private static final short STOP_STATE = 0;

	/**
	* Magic number for the BreakIterator data file format.
	*/
	static final byte[] LABEL = {
	(byte)'B', (byte)'I', (byte)'d', (byte)'a', (byte)'t', (byte)'a',
	(byte)'\0'
	};
	static final int LABEL_LENGTH = LABEL.length;

	/**
	* Version number of the dictionary that was read in.
	*/
	static final byte supportedVersion = 1;

	/**
	* An array length of indices for BMP characters
	*/
	private static final int BMP_INDICES_LENGTH = 512;

	/**
	* Tables that indexes from character values to character category numbers
	*/
	private CompactByteArray charCategoryTable = null;
	private SupplementaryCharacterData supplementaryCharCategoryTable = null;

	/**
	* The table of state transitions used for forward iteration
	*/
	private short[] stateTable = null;

	/**
	* The table of state transitions used to sync up the iterator with the
	* text in backwards and random-access iteration
	*/
	private short[] backwardsStateTable = null;

	/**
	* A list of flags indicating which states in the state table are accepting
	* ("end") states
	*/
	private boolean[] endStates = null;

	/**
	* A list of flags indicating which states in the state table are
	* lookahead states (states which turn lookahead on and off)
	*/
	private boolean[] lookaheadStates = null;

	/**
	* A table for additional data. May be used by a subclass of
	* RuleBasedBreakIterator.
	*/
	private byte[] additionalData = null;

	/**
	* The number of character categories (and, thus, the number of columns in
	* the state tables)
	*/
	private int numCategories;

	/**
	* The character iterator through which this BreakIterator accesses the text
	*/
	private CharacterIterator text = null;

	/**
	* A CRC32 value of all data in datafile
	*/
	private long checksum;

	//=======================================================================
	// constructors
	//=======================================================================

	/**
	* Constructs a RuleBasedBreakIterator using the given rule data.
	*
	* @throws MissingResourceException if the rule data is invalid or corrupted
	*/
	public RuleBasedBreakIterator(String ruleFile, byte[] ruleData) {
	ByteBuffer bb = ByteBuffer.wrap(ruleData);
	try {
	validateRuleData(ruleFile, bb);
	setupTables(ruleFile, bb);
	} catch (BufferUnderflowException bue) {
	MissingResourceException e;
	e = new MissingResourceException("Corrupted rule data file", ruleFile, "");
	e.initCause(bue);
	throw e;
	}
	}

	/**
	* Initializes the fields with the given rule data.
	* The data format is as follows:
	* <pre>
	* BreakIteratorData {
	* u1 magic[7];
	* u1 version;
	* u4 totalDataSize;
	* header_info header;
	* body value;
	* }
	* </pre>
	* <code>totalDataSize</code> is the summation of the size of
	* <code>header_info</code> and <code>body</code> in byte count.
	* <p>
	* In <code>header</code>, each field except for checksum implies the
	* length of each field. Since <code>BMPdataLength</code> is a fixed-length
	* data(512 entries), its length isn't included in <code>header</code>.
	* <code>checksum</code> is a CRC32 value of all in <code>body</code>.
	* <pre>
	* header_info {
	* u4 stateTableLength;
	* u4 backwardsStateTableLength;
	* u4 endStatesLength;
	* u4 lookaheadStatesLength;
	* u4 BMPdataLength;
	* u4 nonBMPdataLength;
	* u4 additionalDataLength;
	* u8 checksum;
	* }
	* </pre>
	* <p>
	*
	* Finally, <code>BMPindices</code> and <code>BMPdata</code> are set to
	* <code>charCategoryTable</code>. <code>nonBMPdata</code> is set to
	* <code>supplementaryCharCategoryTable</code>.
	* <pre>
	* body {
	* u2 stateTable[stateTableLength];
	* u2 backwardsStateTable[backwardsStateTableLength];
	* u1 endStates[endStatesLength];
	* u1 lookaheadStates[lookaheadStatesLength];
	* u2 BMPindices[512];
	* u1 BMPdata[BMPdataLength];
	* u4 nonBMPdata[numNonBMPdataLength];
	* u1 additionalData[additionalDataLength];
	* }
	* </pre>
	*
	* @throws BufferUnderflowException if the end-of-data is reached before
	* setting up all the tables
	*/
	private void setupTables(String ruleFile, ByteBuffer bb) {
	/* Read header_info. */
	int stateTableLength = bb.getInt();
	int backwardsStateTableLength = bb.getInt();
	int endStatesLength = bb.getInt();
	int lookaheadStatesLength = bb.getInt();
	int BMPdataLength = bb.getInt();
	int nonBMPdataLength = bb.getInt();
	int additionalDataLength = bb.getInt();
	checksum = bb.getLong();

	/* Read stateTable[numCategories * numRows] */
	stateTable = new short[stateTableLength];
	for (int i = 0; i < stateTableLength; i++) {
	stateTable[i] = bb.getShort();
	}

	/* Read backwardsStateTable[numCategories * numRows] */
	backwardsStateTable = new short[backwardsStateTableLength];
	for (int i = 0; i < backwardsStateTableLength; i++) {
	backwardsStateTable[i] = bb.getShort();
	}

	/* Read endStates[numRows] */
	endStates = new boolean[endStatesLength];
	for (int i = 0; i < endStatesLength; i++) {
	endStates[i] = bb.get() == 1;
	}

	/* Read lookaheadStates[numRows] */
	lookaheadStates = new boolean[lookaheadStatesLength];
	for (int i = 0; i < lookaheadStatesLength; i++) {
	lookaheadStates[i] = bb.get() == 1;
	}

	/* Read a category table and indices for BMP characters. */
	short[] temp1 = new short[BMP_INDICES_LENGTH]; // BMPindices
	for (int i = 0; i < BMP_INDICES_LENGTH; i++) {
	temp1[i] = bb.getShort();
	}
	byte[] temp2 = new byte[BMPdataLength]; // BMPdata
	bb.get(temp2);
	charCategoryTable = new CompactByteArray(temp1, temp2);

	/* Read a category table for non-BMP characters. */
	int[] temp3 = new int[nonBMPdataLength];
	for (int i = 0; i < nonBMPdataLength; i++) {
	temp3[i] = bb.getInt();
	}
	supplementaryCharCategoryTable = new SupplementaryCharacterData(temp3);

	/* Read additional data */
	if (additionalDataLength > 0) {
	additionalData = new byte[additionalDataLength];
	bb.get(additionalData);
	}
	assert bb.position() == bb.limit();

	/* Set numCategories */
	numCategories = stateTable.length / endStates.length;
	}

	/**
	* Validates the magic number, version, and the length of the given data.
	*
	* @throws BufferUnderflowException if the end-of-data is reached while
	* validating data
	* @throws MissingResourceException if valification failed
	*/
	void validateRuleData(String ruleFile, ByteBuffer bb) {
	/* Verify the magic number. */
	for (int i = 0; i < LABEL_LENGTH; i++) {
	if (bb.get() != LABEL[i]) {
	throw new MissingResourceException("Wrong magic number",
	ruleFile, "");
	}
	}

	/* Verify the version number. */
	byte version = bb.get();
	if (version != supportedVersion) {
	throw new MissingResourceException("Unsupported version(" + version + ")",
	ruleFile, "");
	}

	// Check the length of the rest of data
	int len = bb.getInt();
	if (bb.position() + len != bb.limit()) {
	throw new MissingResourceException("Wrong data length",
	ruleFile, "");
	}
	}

	byte[] getAdditionalData() {
	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;
	}
	}
	}

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