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	/*
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	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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	* published by the Free Software Foundation. Oracle designates this
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	*
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	* 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
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	*
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	/*
	*******************************************************************************
	* Copyright (C) 2009-2014, International Business Machines
	* Corporation and others. All Rights Reserved.
	*******************************************************************************
	*/

	package sun.text.normalizer;

	/**
	* Unicode normalization functionality for standard Unicode normalization or
	* for using custom mapping tables.
	* All instances of this class are unmodifiable/immutable.
	* The Normalizer2 class is not intended for public subclassing.
	* <p>
	* The primary functions are to produce a normalized string and to detect whether
	* a string is already normalized.
	* The most commonly used normalization forms are those defined in
	* http://www.unicode.org/unicode/reports/tr15/
	* However, this API supports additional normalization forms for specialized purposes.
	* For example, NFKC_Casefold is provided via getInstance("nfkc_cf", COMPOSE)
	* and can be used in implementations of UTS #46.
	* <p>
	* Not only are the standard compose and decompose modes supplied,
	* but additional modes are provided as documented in the Mode enum.
	* <p>
	* Some of the functions in this class identify normalization boundaries.
	* At a normalization boundary, the portions of the string
	* before it and starting from it do not interact and can be handled independently.
	* <p>
	* The spanQuickCheckYes() stops at a normalization boundary.
	* When the goal is a normalized string, then the text before the boundary
	* can be copied, and the remainder can be processed with normalizeSecondAndAppend().
	* <p>
	* The hasBoundaryBefore(), hasBoundaryAfter() and isInert() functions test whether
	* a character is guaranteed to be at a normalization boundary,
	* regardless of context.
	* This is used for moving from one normalization boundary to the next
	* or preceding boundary, and for performing iterative normalization.
	* <p>
	* Iterative normalization is useful when only a small portion of a
	* longer string needs to be processed.
	* For example, in ICU, iterative normalization is used by the NormalizationTransliterator
	* (to avoid replacing already-normalized text) and ucol_nextSortKeyPart()
	* (to process only the substring for which sort key bytes are computed).
	* <p>
	* The set of normalization boundaries returned by these functions may not be
	* complete: There may be more boundaries that could be returned.
	* Different functions may return different boundaries.
	* @stable ICU 4.4
	* @author Markus W. Scherer
	*/
	abstract class Normalizer2 {

	/**
	* Returns a Normalizer2 instance for Unicode NFC normalization.
	* Same as getInstance(null, "nfc", Mode.COMPOSE).
	* Returns an unmodifiable singleton instance.
	* @return the requested Normalizer2, if successful
	* @stable ICU 49
	*/
	public static Normalizer2 getNFCInstance() {
	return Norm2AllModes.getNFCInstance().comp;
	}

	/**
	* Returns a Normalizer2 instance for Unicode NFD normalization.
	* Same as getInstance(null, "nfc", Mode.DECOMPOSE).
	* Returns an unmodifiable singleton instance.
	* @return the requested Normalizer2, if successful
	* @stable ICU 49
	*/
	public static Normalizer2 getNFDInstance() {
	return Norm2AllModes.getNFCInstance().decomp;
	}

	/**
	* Returns a Normalizer2 instance for Unicode NFKC normalization.
	* Same as getInstance(null, "nfkc", Mode.COMPOSE).
	* Returns an unmodifiable singleton instance.
	* @return the requested Normalizer2, if successful
	* @stable ICU 49
	*/
	public static Normalizer2 getNFKCInstance() {
	return Norm2AllModes.getNFKCInstance().comp;
	}

	/**
	* Returns a Normalizer2 instance for Unicode NFKD normalization.
	* Same as getInstance(null, "nfkc", Mode.DECOMPOSE).
	* Returns an unmodifiable singleton instance.
	* @return the requested Normalizer2, if successful
	* @stable ICU 49
	*/
	public static Normalizer2 getNFKDInstance() {
	return Norm2AllModes.getNFKCInstance().decomp;
	}

	/**
	* Returns the normalized form of the source string.
	* @param src source string
	* @return normalized src
	* @stable ICU 4.4
	*/
	public String normalize(CharSequence src) {
	if(src instanceof String) {
	// Fastpath: Do not construct a new String if the src is a String
	// and is already normalized.
	int spanLength=spanQuickCheckYes(src);
	if(spanLength==src.length()) {
	return (String)src;
	}
	if (spanLength != 0) {
	StringBuilder sb=new StringBuilder(src.length()).append(src, 0, spanLength);
	return normalizeSecondAndAppend(sb, src.subSequence(spanLength, src.length())).toString();
	}
	}
	return normalize(src, new StringBuilder(src.length())).toString();
	}

	/**
	* Writes the normalized form of the source string to the destination string
	* (replacing its contents) and returns the destination string.
	* The source and destination strings must be different objects.
	* @param src source string
	* @param dest destination string; its contents is replaced with normalized src
	* @return dest
	* @stable ICU 4.4
	*/
	public abstract StringBuilder normalize(CharSequence src, StringBuilder dest);

	/**
	* Writes the normalized form of the source string to the destination Appendable
	* and returns the destination Appendable.
	* The source and destination strings must be different objects.
	*
	* <p>Any {@link java.io.IOException} is wrapped into a {@link com.ibm.icu.util.ICUUncheckedIOException}.
	*
	* @param src source string
	* @param dest destination Appendable; gets normalized src appended
	* @return dest
	* @stable ICU 4.6
	*/
	public abstract Appendable normalize(CharSequence src, Appendable dest);

	/**
	* Appends the normalized form of the second string to the first string
	* (merging them at the boundary) and returns the first string.
	* The result is normalized if the first string was normalized.
	* The first and second strings must be different objects.
	* @param first string, should be normalized
	* @param second string, will be normalized
	* @return first
	* @stable ICU 4.4
	*/
	public abstract StringBuilder normalizeSecondAndAppend(
	StringBuilder first, CharSequence second);

	/**
	* Appends the second string to the first string
	* (merging them at the boundary) and returns the first string.
	* The result is normalized if both the strings were normalized.
	* The first and second strings must be different objects.
	* @param first string, should be normalized
	* @param second string, should be normalized
	* @return first
	* @stable ICU 4.4
	*/
	public abstract StringBuilder append(StringBuilder first, CharSequence second);

	/**
	* Gets the decomposition mapping of c.
	* Roughly equivalent to normalizing the String form of c
	* on a DECOMPOSE Normalizer2 instance, but much faster, and except that this function
	* returns null if c does not have a decomposition mapping in this instance's data.
	* This function is independent of the mode of the Normalizer2.
	* @param c code point
	* @return c's decomposition mapping, if any; otherwise null
	* @stable ICU 4.6
	*/
	public abstract String getDecomposition(int c);

	/**
	* Gets the combining class of c.
	* The default implementation returns 0
	* but all standard implementations return the Unicode Canonical_Combining_Class value.
	* @param c code point
	* @return c's combining class
	* @stable ICU 49
	*/
	public int getCombiningClass(int c) { return 0; }

	/**
	* Tests if the string is normalized.
	* Internally, in cases where the quickCheck() method would return "maybe"
	* (which is only possible for the two COMPOSE modes) this method
	* resolves to "yes" or "no" to provide a definitive result,
	* at the cost of doing more work in those cases.
	* @param s input string
	* @return true if s is normalized
	* @stable ICU 4.4
	*/
	public abstract boolean isNormalized(CharSequence s);

	/**
	* Returns the end of the normalized substring of the input string.
	* In other words, with <code>end=spanQuickCheckYes(s);</code>
	* the substring <code>s.subSequence(0, end)</code>
	* will pass the quick check with a "yes" result.
	* <p>
	* The returned end index is usually one or more characters before the
	* "no" or "maybe" character: The end index is at a normalization boundary.
	* (See the class documentation for more about normalization boundaries.)
	* <p>
	* When the goal is a normalized string and most input strings are expected
	* to be normalized already, then call this method,
	* and if it returns a prefix shorter than the input string,
	* copy that prefix and use normalizeSecondAndAppend() for the remainder.
	* @param s input string
	* @return "yes" span end index
	* @stable ICU 4.4
	*/
	public abstract int spanQuickCheckYes(CharSequence s);

	/**
	* Tests if the character always has a normalization boundary before it,
	* regardless of context.
	* If true, then the character does not normalization-interact with
	* preceding characters.
	* In other words, a string containing this character can be normalized
	* by processing portions before this character and starting from this
	* character independently.
	* This is used for iterative normalization. See the class documentation for details.
	* @param c character to test
	* @return true if c has a normalization boundary before it
	* @stable ICU 4.4
	*/
	public abstract boolean hasBoundaryBefore(int c);

	/**
	* Sole constructor. (For invocation by subclass constructors,
	* typically implicit.)
	* @internal
	* deprecated This API is ICU internal only.
	*/
	protected Normalizer2() {
	}
	}

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