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	/*
	* Copyright (c) 2011, 2021, 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.
	*/

	package sun.nio.cs;

	import jdk.internal.access.JavaLangAccess;
	import jdk.internal.access.SharedSecrets;

	import java.nio.Buffer;
	import java.nio.ByteBuffer;
	import java.nio.CharBuffer;
	import java.nio.charset.Charset;
	import java.nio.charset.CharsetDecoder;
	import java.nio.charset.CharsetEncoder;
	import java.nio.charset.CoderResult;
	import java.nio.charset.CodingErrorAction;

	/* Legal CESU-8 Byte Sequences
	*
	* # Code Points Bits Bit/Byte pattern
	* 1 7 0xxxxxxx
	* U+0000..U+007F 00..7F
	*
	* 2 11 110xxxxx 10xxxxxx
	* U+0080..U+07FF C2..DF 80..BF
	*
	* 3 16 1110xxxx 10xxxxxx 10xxxxxx
	* U+0800..U+0FFF E0 A0..BF 80..BF
	* U+1000..U+FFFF E1..EF 80..BF 80..BF
	*
	*/

	class CESU_8 extends Unicode
	{
	public CESU_8() {
	super("CESU-8", StandardCharsets.aliases_CESU_8());
	}

	public String historicalName() {
	return "CESU8";
	}

	public CharsetDecoder newDecoder() {
	return new Decoder(this);
	}

	public CharsetEncoder newEncoder() {
	return new Encoder(this);
	}

	private static final void updatePositions(Buffer src, int sp,
	Buffer dst, int dp) {
	src.position(sp - src.arrayOffset());
	dst.position(dp - dst.arrayOffset());
	}

	private static class Decoder extends CharsetDecoder
	implements ArrayDecoder {

	private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();

	private Decoder(Charset cs) {
	super(cs, 1.0f, 1.0f);
	}

	private static boolean isNotContinuation(int b) {
	return (b & 0xc0) != 0x80;
	}

	// [E0] [A0..BF] [80..BF]
	// [E1..EF] [80..BF] [80..BF]
	private static boolean isMalformed3(int b1, int b2, int b3) {
	return (b1 == (byte)0xe0 && (b2 & 0xe0) == 0x80) \|\|
	(b2 & 0xc0) != 0x80 \|\| (b3 & 0xc0) != 0x80;
	}

	// only used when there is only one byte left in src buffer
	private static boolean isMalformed3_2(int b1, int b2) {
	return (b1 == (byte)0xe0 && (b2 & 0xe0) == 0x80) \|\|
	(b2 & 0xc0) != 0x80;
	}

	private static CoderResult malformedN(ByteBuffer src, int nb) {
	switch (nb) {
	case 1:
	case 2: // always 1
	return CoderResult.malformedForLength(1);
	case 3:
	int b1 = src.get();
	int b2 = src.get(); // no need to lookup b3
	return CoderResult.malformedForLength(
	((b1 == (byte)0xe0 && (b2 & 0xe0) == 0x80) \|\|
	isNotContinuation(b2)) ? 1 : 2);
	case 4: // we don't care the speed here
	b1 = src.get() & 0xff;
	b2 = src.get() & 0xff;
	if (b1 > 0xf4 \|\|
	(b1 == 0xf0 && (b2 < 0x90 \|\| b2 > 0xbf)) \|\|
	(b1 == 0xf4 && (b2 & 0xf0) != 0x80) \|\|
	isNotContinuation(b2))
	return CoderResult.malformedForLength(1);
	if (isNotContinuation(src.get()))
	return CoderResult.malformedForLength(2);
	return CoderResult.malformedForLength(3);
	default:
	assert false;
	return null;
	}
	}

	private static CoderResult malformed(ByteBuffer src, int sp,
	CharBuffer dst, int dp,
	int nb)
	{
	src.position(sp - src.arrayOffset());
	CoderResult cr = malformedN(src, nb);
	updatePositions(src, sp, dst, dp);
	return cr;
	}


	private static CoderResult malformed(ByteBuffer src,
	int mark, int nb)
	{
	src.position(mark);
	CoderResult cr = malformedN(src, nb);
	src.position(mark);
	return cr;
	}

	private static CoderResult malformedForLength(ByteBuffer src,
	int sp,
	CharBuffer dst,
	int dp,
	int malformedNB)
	{
	updatePositions(src, sp, dst, dp);
	return CoderResult.malformedForLength(malformedNB);
	}

	private static CoderResult malformedForLength(ByteBuffer src,
	int mark,
	int malformedNB)
	{
	src.position(mark);
	return CoderResult.malformedForLength(malformedNB);
	}


	private static CoderResult xflow(Buffer src, int sp, int sl,
	Buffer dst, int dp, int nb) {
	updatePositions(src, sp, dst, dp);
	return (nb == 0 \|\| sl - sp < nb)
	? CoderResult.UNDERFLOW : CoderResult.OVERFLOW;
	}

	private static CoderResult xflow(Buffer src, int mark, int nb) {
	src.position(mark);
	return (nb == 0 \|\| src.remaining() < nb)
	? CoderResult.UNDERFLOW : CoderResult.OVERFLOW;
	}

	private CoderResult decodeArrayLoop(ByteBuffer src,
	CharBuffer dst)
	{
	// This method is optimized for ASCII input.
	byte[] sa = src.array();
	int soff = src.arrayOffset();
	int sp = soff + src.position();
	int sl = soff + src.limit();

	char[] da = dst.array();
	int doff = dst.arrayOffset();
	int dp = doff + dst.position();
	int dl = doff + dst.limit();

	int n = JLA.decodeASCII(sa, sp, da, dp, Math.min(sl - sp, dl - dp));
	sp += n;
	dp += n;

	while (sp < sl) {
	int b1 = sa[sp];
	if (b1 >= 0) {
	// 1 byte, 7 bits: 0xxxxxxx
	if (dp >= dl)
	return xflow(src, sp, sl, dst, dp, 1);
	da[dp++] = (char) b1;
	sp++;
	} else if ((b1 >> 5) == -2 && (b1 & 0x1e) != 0) {
	// 2 bytes, 11 bits: 110xxxxx 10xxxxxx
	if (sl - sp < 2 \|\| dp >= dl)
	return xflow(src, sp, sl, dst, dp, 2);
	int b2 = sa[sp + 1];
	if (isNotContinuation(b2))
	return malformedForLength(src, sp, dst, dp, 1);
	da[dp++] = (char) (((b1 << 6) ^ b2)
	^
	(((byte) 0xC0 << 6) ^
	((byte) 0x80 << 0)));
	sp += 2;
	} else if ((b1 >> 4) == -2) {
	// 3 bytes, 16 bits: 1110xxxx 10xxxxxx 10xxxxxx
	int srcRemaining = sl - sp;
	if (srcRemaining < 3 \|\| dp >= dl) {
	if (srcRemaining > 1 && isMalformed3_2(b1, sa[sp + 1]))
	return malformedForLength(src, sp, dst, dp, 1);
	return xflow(src, sp, sl, dst, dp, 3);
	}
	int b2 = sa[sp + 1];
	int b3 = sa[sp + 2];
	if (isMalformed3(b1, b2, b3))
	return malformed(src, sp, dst, dp, 3);
	da[dp++] = (char)
	((b1 << 12) ^
	(b2 << 6) ^
	(b3 ^
	(((byte) 0xE0 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	sp += 3;
	} else {
	return malformed(src, sp, dst, dp, 1);
	}
	}
	return xflow(src, sp, sl, dst, dp, 0);
	}

	private CoderResult decodeBufferLoop(ByteBuffer src,
	CharBuffer dst)
	{
	int mark = src.position();
	int limit = src.limit();
	while (mark < limit) {
	int b1 = src.get();
	if (b1 >= 0) {
	// 1 byte, 7 bits: 0xxxxxxx
	if (dst.remaining() < 1)
	return xflow(src, mark, 1); // overflow
	dst.put((char) b1);
	mark++;
	} else if ((b1 >> 5) == -2 && (b1 & 0x1e) != 0) {
	// 2 bytes, 11 bits: 110xxxxx 10xxxxxx
	if (limit - mark < 2\|\| dst.remaining() < 1)
	return xflow(src, mark, 2);
	int b2 = src.get();
	if (isNotContinuation(b2))
	return malformedForLength(src, mark, 1);
	dst.put((char) (((b1 << 6) ^ b2)
	^
	(((byte) 0xC0 << 6) ^
	((byte) 0x80 << 0))));
	mark += 2;
	} else if ((b1 >> 4) == -2) {
	// 3 bytes, 16 bits: 1110xxxx 10xxxxxx 10xxxxxx
	int srcRemaining = limit - mark;
	if (srcRemaining < 3 \|\| dst.remaining() < 1) {
	if (srcRemaining > 1 && isMalformed3_2(b1, src.get()))
	return malformedForLength(src, mark, 1);
	return xflow(src, mark, 3);
	}
	int b2 = src.get();
	int b3 = src.get();
	if (isMalformed3(b1, b2, b3))
	return malformed(src, mark, 3);
	dst.put((char)
	((b1 << 12) ^
	(b2 << 6) ^
	(b3 ^
	(((byte) 0xE0 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0)))));
	mark += 3;
	} else {
	return malformed(src, mark, 1);
	}
	}
	return xflow(src, mark, 0);
	}

	protected CoderResult decodeLoop(ByteBuffer src,
	CharBuffer dst)
	{
	if (src.hasArray() && dst.hasArray())
	return decodeArrayLoop(src, dst);
	else
	return decodeBufferLoop(src, dst);
	}

	private static ByteBuffer getByteBuffer(ByteBuffer bb, byte[] ba, int sp)
	{
	if (bb == null)
	bb = ByteBuffer.wrap(ba);
	bb.position(sp);
	return bb;
	}

	// returns -1 if there is/are malformed byte(s) and the
	// "action" for malformed input is not REPLACE.
	public int decode(byte[] sa, int sp, int len, char[] da) {
	final int sl = sp + len;
	int dp = 0;
	int dlASCII = Math.min(len, da.length);
	ByteBuffer bb = null; // only necessary if malformed

	// ASCII only optimized loop
	while (dp < dlASCII && sa[sp] >= 0)
	da[dp++] = (char) sa[sp++];

	while (sp < sl) {
	int b1 = sa[sp++];
	if (b1 >= 0) {
	// 1 byte, 7 bits: 0xxxxxxx
	da[dp++] = (char) b1;
	} else if ((b1 >> 5) == -2 && (b1 & 0x1e) != 0) {
	// 2 bytes, 11 bits: 110xxxxx 10xxxxxx
	if (sp < sl) {
	int b2 = sa[sp++];
	if (isNotContinuation(b2)) {
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	da[dp++] = replacement().charAt(0);
	sp--; // malformedN(bb, 2) always returns 1
	} else {
	da[dp++] = (char) (((b1 << 6) ^ b2)^
	(((byte) 0xC0 << 6) ^
	((byte) 0x80 << 0)));
	}
	continue;
	}
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	da[dp++] = replacement().charAt(0);
	return dp;
	} else if ((b1 >> 4) == -2) {
	// 3 bytes, 16 bits: 1110xxxx 10xxxxxx 10xxxxxx
	if (sp + 1 < sl) {
	int b2 = sa[sp++];
	int b3 = sa[sp++];
	if (isMalformed3(b1, b2, b3)) {
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	da[dp++] = replacement().charAt(0);
	sp -=3;
	bb = getByteBuffer(bb, sa, sp);
	sp += malformedN(bb, 3).length();
	} else {
	da[dp++] = (char)((b1 << 12) ^
	(b2 << 6) ^
	(b3 ^
	(((byte) 0xE0 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	}
	continue;
	}
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	if (sp < sl && isMalformed3_2(b1, sa[sp])) {
	da[dp++] = replacement().charAt(0);
	continue;

	}
	da[dp++] = replacement().charAt(0);
	return dp;
	} else {
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	da[dp++] = replacement().charAt(0);
	}
	}
	return dp;
	}
	}

	private static class Encoder extends CharsetEncoder
	implements ArrayEncoder {

	private Encoder(Charset cs) {
	super(cs, 1.1f, 3.0f);
	}

	public boolean canEncode(char c) {
	return !Character.isSurrogate(c);
	}

	public boolean isLegalReplacement(byte[] repl) {
	return ((repl.length == 1 && repl[0] >= 0) \|\|
	super.isLegalReplacement(repl));
	}

	private static CoderResult overflow(CharBuffer src, int sp,
	ByteBuffer dst, int dp) {
	updatePositions(src, sp, dst, dp);
	return CoderResult.OVERFLOW;
	}

	private static CoderResult overflow(CharBuffer src, int mark) {
	src.position(mark);
	return CoderResult.OVERFLOW;
	}

	private static void to3Bytes(byte[] da, int dp, char c) {
	da[dp] = (byte)(0xe0 \| ((c >> 12)));
	da[dp + 1] = (byte)(0x80 \| ((c >> 6) & 0x3f));
	da[dp + 2] = (byte)(0x80 \| (c & 0x3f));
	}

	private static void to3Bytes(ByteBuffer dst, char c) {
	dst.put((byte)(0xe0 \| ((c >> 12))));
	dst.put((byte)(0x80 \| ((c >> 6) & 0x3f)));
	dst.put((byte)(0x80 \| (c & 0x3f)));
	}

	private Surrogate.Parser sgp;
	private char[] c2;
	private CoderResult encodeArrayLoop(CharBuffer src,
	ByteBuffer dst)
	{
	char[] sa = src.array();
	int sp = src.arrayOffset() + src.position();
	int sl = src.arrayOffset() + src.limit();

	byte[] da = dst.array();
	int dp = dst.arrayOffset() + dst.position();
	int dl = dst.arrayOffset() + dst.limit();
	int dlASCII = dp + Math.min(sl - sp, dl - dp);

	// ASCII only loop
	while (dp < dlASCII && sa[sp] < '\u0080')
	da[dp++] = (byte) sa[sp++];
	while (sp < sl) {
	char c = sa[sp];
	if (c < 0x80) {
	// Have at most seven bits
	if (dp >= dl)
	return overflow(src, sp, dst, dp);
	da[dp++] = (byte)c;
	} else if (c < 0x800) {
	// 2 bytes, 11 bits
	if (dl - dp < 2)
	return overflow(src, sp, dst, dp);
	da[dp++] = (byte)(0xc0 \| (c >> 6));
	da[dp++] = (byte)(0x80 \| (c & 0x3f));
	} else if (Character.isSurrogate(c)) {
	// Have a surrogate pair
	if (sgp == null)
	sgp = new Surrogate.Parser();
	int uc = sgp.parse(c, sa, sp, sl);
	if (uc < 0) {
	updatePositions(src, sp, dst, dp);
	return sgp.error();
	}
	if (dl - dp < 6)
	return overflow(src, sp, dst, dp);
	to3Bytes(da, dp, Character.highSurrogate(uc));
	dp += 3;
	to3Bytes(da, dp, Character.lowSurrogate(uc));
	dp += 3;
	sp++; // 2 chars
	} else {
	// 3 bytes, 16 bits
	if (dl - dp < 3)
	return overflow(src, sp, dst, dp);
	to3Bytes(da, dp, c);
	dp += 3;
	}
	sp++;
	}
	updatePositions(src, sp, dst, dp);
	return CoderResult.UNDERFLOW;
	}

	private CoderResult encodeBufferLoop(CharBuffer src,
	ByteBuffer dst)
	{
	int mark = src.position();
	while (src.hasRemaining()) {
	char c = src.get();
	if (c < 0x80) {
	// Have at most seven bits
	if (!dst.hasRemaining())
	return overflow(src, mark);
	dst.put((byte)c);
	} else if (c < 0x800) {
	// 2 bytes, 11 bits
	if (dst.remaining() < 2)
	return overflow(src, mark);
	dst.put((byte)(0xc0 \| (c >> 6)));
	dst.put((byte)(0x80 \| (c & 0x3f)));
	} else if (Character.isSurrogate(c)) {
	// Have a surrogate pair
	if (sgp == null)
	sgp = new Surrogate.Parser();
	int uc = sgp.parse(c, src);
	if (uc < 0) {
	src.position(mark);
	return sgp.error();
	}
	if (dst.remaining() < 6)
	return overflow(src, mark);
	to3Bytes(dst, Character.highSurrogate(uc));
	to3Bytes(dst, Character.lowSurrogate(uc));
	mark++; // 2 chars
	} else {
	// 3 bytes, 16 bits
	if (dst.remaining() < 3)
	return overflow(src, mark);
	to3Bytes(dst, c);
	}
	mark++;
	}
	src.position(mark);
	return CoderResult.UNDERFLOW;
	}

	protected final CoderResult encodeLoop(CharBuffer src,
	ByteBuffer dst)
	{
	if (src.hasArray() && dst.hasArray())
	return encodeArrayLoop(src, dst);
	else
	return encodeBufferLoop(src, dst);
	}

	// returns -1 if there is malformed char(s) and the
	// "action" for malformed input is not REPLACE.
	public int encode(char[] sa, int sp, int len, byte[] da) {
	int sl = sp + len;
	int dp = 0;
	int dlASCII = dp + Math.min(len, da.length);

	// ASCII only optimized loop
	while (dp < dlASCII && sa[sp] < '\u0080')
	da[dp++] = (byte) sa[sp++];

	while (sp < sl) {
	char c = sa[sp++];
	if (c < 0x80) {
	// Have at most seven bits
	da[dp++] = (byte)c;
	} else if (c < 0x800) {
	// 2 bytes, 11 bits
	da[dp++] = (byte)(0xc0 \| (c >> 6));
	da[dp++] = (byte)(0x80 \| (c & 0x3f));
	} else if (Character.isSurrogate(c)) {
	if (sgp == null)
	sgp = new Surrogate.Parser();
	int uc = sgp.parse(c, sa, sp - 1, sl);
	if (uc < 0) {
	if (malformedInputAction() != CodingErrorAction.REPLACE)
	return -1;
	da[dp++] = replacement()[0];
	} else {
	to3Bytes(da, dp, Character.highSurrogate(uc));
	dp += 3;
	to3Bytes(da, dp, Character.lowSurrogate(uc));
	dp += 3;
	sp++; // 2 chars
	}
	} else {
	// 3 bytes, 16 bits
	to3Bytes(da, dp, c);
	dp += 3;
	}
	}
	return dp;
	}
	}
	}

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