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	/*
	* Copyright (c) 2015, 2020, 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.
	*/

	/*
	*******************************************************************************
	* Copyright (C) 2009-2014, International Business Machines
	* Corporation and others. All Rights Reserved.
	*******************************************************************************
	*/
	package jdk.internal.icu.text;

	import java.io.IOException;

	/**
	* Normalization filtered by a UnicodeSet.
	* Normalizes portions of the text contained in the filter set and leaves
	* portions not contained in the filter set unchanged.
	* Filtering is done via UnicodeSet.span(..., UnicodeSet.SpanCondition.SIMPLE).
	* Not-in-the-filter text is treated as "is normalized" and "quick check yes".
	* This class implements all of (and only) the Normalizer2 API.
	* An instance of this class is unmodifiable/immutable.
	* @stable ICU 4.4
	* @author Markus W. Scherer
	*/
	class FilteredNormalizer2 extends Normalizer2 {

	/**
	* Constructs a filtered normalizer wrapping any Normalizer2 instance
	* and a filter set.
	* Both are aliased and must not be modified or deleted while this object
	* is used.
	* The filter set should be frozen; otherwise the performance will suffer greatly.
	* @param n2 wrapped Normalizer2 instance
	* @param filterSet UnicodeSet which determines the characters to be normalized
	* @stable ICU 4.4
	*/
	public FilteredNormalizer2(Normalizer2 n2, UnicodeSet filterSet) {
	norm2=n2;
	set=filterSet;
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public StringBuilder normalize(CharSequence src, StringBuilder dest) {
	if(dest==src) {
	throw new IllegalArgumentException();
	}
	dest.setLength(0);
	normalize(src, dest, UnicodeSet.SpanCondition.SIMPLE);
	return dest;
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.6
	*/
	@Override
	public Appendable normalize(CharSequence src, Appendable dest) {
	if(dest==src) {
	throw new IllegalArgumentException();
	}
	return normalize(src, dest, UnicodeSet.SpanCondition.SIMPLE);
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public StringBuilder normalizeSecondAndAppend(
	StringBuilder first, CharSequence second) {
	return normalizeSecondAndAppend(first, second, true);
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public StringBuilder append(StringBuilder first, CharSequence second) {
	return normalizeSecondAndAppend(first, second, false);
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.6
	*/
	@Override
	public String getDecomposition(int c) {
	return set.contains(c) ? norm2.getDecomposition(c) : null;
	}

	/**
	* {@inheritDoc}
	* @stable ICU 49
	*/
	@Override
	public int getCombiningClass(int c) {
	return set.contains(c) ? norm2.getCombiningClass(c) : 0;
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public boolean isNormalized(CharSequence s) {
	UnicodeSet.SpanCondition spanCondition=UnicodeSet.SpanCondition.SIMPLE;
	for(int prevSpanLimit=0; prevSpanLimit<s.length();) {
	int spanLimit=set.span(s, prevSpanLimit, spanCondition);
	if(spanCondition==UnicodeSet.SpanCondition.NOT_CONTAINED) {
	spanCondition=UnicodeSet.SpanCondition.SIMPLE;
	} else {
	if(!norm2.isNormalized(s.subSequence(prevSpanLimit, spanLimit))) {
	return false;
	}
	spanCondition=UnicodeSet.SpanCondition.NOT_CONTAINED;
	}
	prevSpanLimit=spanLimit;
	}
	return true;
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public int spanQuickCheckYes(CharSequence s) {
	UnicodeSet.SpanCondition spanCondition=UnicodeSet.SpanCondition.SIMPLE;
	for(int prevSpanLimit=0; prevSpanLimit<s.length();) {
	int spanLimit=set.span(s, prevSpanLimit, spanCondition);
	if(spanCondition==UnicodeSet.SpanCondition.NOT_CONTAINED) {
	spanCondition=UnicodeSet.SpanCondition.SIMPLE;
	} else {
	int yesLimit=
	prevSpanLimit+
	norm2.spanQuickCheckYes(s.subSequence(prevSpanLimit, spanLimit));
	if(yesLimit<spanLimit) {
	return yesLimit;
	}
	spanCondition=UnicodeSet.SpanCondition.NOT_CONTAINED;
	}
	prevSpanLimit=spanLimit;
	}
	return s.length();
	}

	/**
	* {@inheritDoc}
	* @stable ICU 4.4
	*/
	@Override
	public boolean hasBoundaryBefore(int c) {
	return !set.contains(c) \|\| norm2.hasBoundaryBefore(c);
	}

	// Internal: No argument checking, and appends to dest.
	// Pass as input spanCondition the one that is likely to yield a non-zero
	// span length at the start of src.
	// For set=[:age=3.2:], since almost all common characters were in Unicode 3.2,
	// UnicodeSet.SpanCondition.SIMPLE should be passed in for the start of src
	// and UnicodeSet.SpanCondition.NOT_CONTAINED should be passed in if we continue after
	// an in-filter prefix.
	private Appendable normalize(CharSequence src, Appendable dest,
	UnicodeSet.SpanCondition spanCondition) {
	// Don't throw away destination buffer between iterations.
	StringBuilder tempDest=new StringBuilder();
	try {
	for(int prevSpanLimit=0; prevSpanLimit<src.length();) {
	int spanLimit=set.span(src, prevSpanLimit, spanCondition);
	int spanLength=spanLimit-prevSpanLimit;
	if(spanCondition==UnicodeSet.SpanCondition.NOT_CONTAINED) {
	if(spanLength!=0) {
	dest.append(src, prevSpanLimit, spanLimit);
	}
	spanCondition=UnicodeSet.SpanCondition.SIMPLE;
	} else {
	if(spanLength!=0) {
	// Not norm2.normalizeSecondAndAppend() because we do not want
	// to modify the non-filter part of dest.
	dest.append(norm2.normalize(src.subSequence(prevSpanLimit, spanLimit), tempDest));
	}
	spanCondition=UnicodeSet.SpanCondition.NOT_CONTAINED;
	}
	prevSpanLimit=spanLimit;
	}
	} catch(IOException e) {
	throw new InternalError(e.toString(), e);
	}
	return dest;
	}

	private StringBuilder normalizeSecondAndAppend(StringBuilder first, CharSequence second,
	boolean doNormalize) {
	if(first==second) {
	throw new IllegalArgumentException();
	}
	if(first.length()==0) {
	if(doNormalize) {
	return normalize(second, first);
	} else {
	return first.append(second);
	}
	}
	// merge the in-filter suffix of the first string with the in-filter prefix of the second
	int prefixLimit=set.span(second, 0, UnicodeSet.SpanCondition.SIMPLE);
	if(prefixLimit!=0) {
	CharSequence prefix=second.subSequence(0, prefixLimit);
	int suffixStart=set.spanBack(first, 0x7fffffff, UnicodeSet.SpanCondition.SIMPLE);
	if(suffixStart==0) {
	if(doNormalize) {
	norm2.normalizeSecondAndAppend(first, prefix);
	} else {
	norm2.append(first, prefix);
	}
	} else {
	StringBuilder middle=new StringBuilder(
	first.subSequence(suffixStart, first.length()));
	if(doNormalize) {
	norm2.normalizeSecondAndAppend(middle, prefix);
	} else {
	norm2.append(middle, prefix);
	}
	first.delete(suffixStart, 0x7fffffff).append(middle);
	}
	}
	if(prefixLimit<second.length()) {
	CharSequence rest=second.subSequence(prefixLimit, second.length());
	if(doNormalize) {
	normalize(rest, first, UnicodeSet.SpanCondition.NOT_CONTAINED);
	} else {
	first.append(rest);
	}
	}
	return first;
	}

	private Normalizer2 norm2;
	private UnicodeSet set;
	};

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