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	/*
	* Copyright (c) 2000, 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 UTF-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
	*
	* 4 21 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
	* U+10000..U+3FFFF F0 90..BF 80..BF 80..BF
	* U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF
	* U+100000..U10FFFF F4 80..8F 80..BF 80..BF
	*
	*/

	public final class UTF_8 extends Unicode {

	public static final UTF_8 INSTANCE = new UTF_8();

	public UTF_8() {
	super("UTF-8", StandardCharsets.aliases_UTF_8());
	}

	public String historicalName() {
	return "UTF8";
	}

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

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

	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 {

	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;
	}

	// [F0] [90..BF] [80..BF] [80..BF]
	// [F1..F3] [80..BF] [80..BF] [80..BF]
	// [F4] [80..8F] [80..BF] [80..BF]
	// only check 80-be range here, the [0xf0,0x80...] and [0xf4,0x90-...]
	// will be checked by Character.isSupplementaryCodePoint(uc)
	private static boolean isMalformed4(int b2, int b3, int b4) {
	return (b2 & 0xc0) != 0x80 \|\| (b3 & 0xc0) != 0x80 \|\|
	(b4 & 0xc0) != 0x80;
	}

	// only used when there is less than 4 bytes left in src buffer.
	// both b1 and b2 should be "& 0xff" before passed in.
	private static boolean isMalformed4_2(int b1, int b2) {
	return (b1 == 0xf0 && (b2 < 0x90 \|\| b2 > 0xbf)) \|\|
	(b1 == 0xf4 && (b2 & 0xf0) != 0x80) \|\|
	(b2 & 0xc0) != 0x80;
	}

	// tests if b1 and b2 are malformed as the first 2 bytes of a
	// legal`4-byte utf-8 byte sequence.
	// only used when there is less than 4 bytes left in src buffer,
	// after isMalformed4_2 has been invoked.
	private static boolean isMalformed4_3(int b3) {
	return (b3 & 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
	// [C2..DF] [80..BF]
	if (sl - sp < 2 \|\| dp >= dl)
	return xflow(src, sp, sl, dst, dp, 2);
	int b2 = sa[sp + 1];
	// Now we check the first byte of 2-byte sequence as
	// if ((b1 >> 5) == -2 && (b1 & 0x1e) != 0)
	// no longer need to check b1 against c1 & c0 for
	// malformed as we did in previous version
	// (b1 & 0x1e) == 0x0 \|\| (b2 & 0xc0) != 0x80;
	// only need to check the second byte b2.
	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);
	char c = (char)
	((b1 << 12) ^
	(b2 << 6) ^
	(b3 ^
	(((byte) 0xE0 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	if (Character.isSurrogate(c))
	return malformedForLength(src, sp, dst, dp, 3);
	da[dp++] = c;
	sp += 3;
	} else if ((b1 >> 3) == -2) {
	// 4 bytes, 21 bits: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
	int srcRemaining = sl - sp;
	if (srcRemaining < 4 \|\| dl - dp < 2) {
	b1 &= 0xff;
	if (b1 > 0xf4 \|\|
	srcRemaining > 1 && isMalformed4_2(b1, sa[sp + 1] & 0xff))
	return malformedForLength(src, sp, dst, dp, 1);
	if (srcRemaining > 2 && isMalformed4_3(sa[sp + 2]))
	return malformedForLength(src, sp, dst, dp, 2);
	return xflow(src, sp, sl, dst, dp, 4);
	}
	int b2 = sa[sp + 1];
	int b3 = sa[sp + 2];
	int b4 = sa[sp + 3];
	int uc = ((b1 << 18) ^
	(b2 << 12) ^
	(b3 << 6) ^
	(b4 ^
	(((byte) 0xF0 << 18) ^
	((byte) 0x80 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	if (isMalformed4(b2, b3, b4) \|\|
	// shortest form check
	!Character.isSupplementaryCodePoint(uc)) {
	return malformed(src, sp, dst, dp, 4);
	}
	da[dp++] = Character.highSurrogate(uc);
	da[dp++] = Character.lowSurrogate(uc);
	sp += 4;
	} 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);
	char c = (char)
	((b1 << 12) ^
	(b2 << 6) ^
	(b3 ^
	(((byte) 0xE0 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	if (Character.isSurrogate(c))
	return malformedForLength(src, mark, 3);
	dst.put(c);
	mark += 3;
	} else if ((b1 >> 3) == -2) {
	// 4 bytes, 21 bits: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
	int srcRemaining = limit - mark;
	if (srcRemaining < 4 \|\| dst.remaining() < 2) {
	b1 &= 0xff;
	if (b1 > 0xf4 \|\|
	srcRemaining > 1 && isMalformed4_2(b1, src.get() & 0xff))
	return malformedForLength(src, mark, 1);
	if (srcRemaining > 2 && isMalformed4_3(src.get()))
	return malformedForLength(src, mark, 2);
	return xflow(src, mark, 4);
	}
	int b2 = src.get();
	int b3 = src.get();
	int b4 = src.get();
	int uc = ((b1 << 18) ^
	(b2 << 12) ^
	(b3 << 6) ^
	(b4 ^
	(((byte) 0xF0 << 18) ^
	((byte) 0x80 << 12) ^
	((byte) 0x80 << 6) ^
	((byte) 0x80 << 0))));
	if (isMalformed4(b2, b3, b4) \|\|
	// shortest form check
	!Character.isSupplementaryCodePoint(uc)) {
	return malformed(src, mark, 4);
	}
	dst.put(Character.highSurrogate(uc));
	dst.put(Character.lowSurrogate(uc));
	mark += 4;
	} 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 final class Encoder extends CharsetEncoder {

	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 Surrogate.Parser sgp;
	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 < 4)
	return overflow(src, sp, dst, dp);
	da[dp++] = (byte)(0xf0 \| ((uc >> 18)));
	da[dp++] = (byte)(0x80 \| ((uc >> 12) & 0x3f));
	da[dp++] = (byte)(0x80 \| ((uc >> 6) & 0x3f));
	da[dp++] = (byte)(0x80 \| (uc & 0x3f));
	sp++; // 2 chars
	} else {
	// 3 bytes, 16 bits
	if (dl - dp < 3)
	return overflow(src, sp, dst, dp);
	da[dp++] = (byte)(0xe0 \| ((c >> 12)));
	da[dp++] = (byte)(0x80 \| ((c >> 6) & 0x3f));
	da[dp++] = (byte)(0x80 \| (c & 0x3f));
	}
	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() < 4)
	return overflow(src, mark);
	dst.put((byte)(0xf0 \| ((uc >> 18))));
	dst.put((byte)(0x80 \| ((uc >> 12) & 0x3f)));
	dst.put((byte)(0x80 \| ((uc >> 6) & 0x3f)));
	dst.put((byte)(0x80 \| (uc & 0x3f)));
	mark++; // 2 chars
	} else {
	// 3 bytes, 16 bits
	if (dst.remaining() < 3)
	return overflow(src, mark);
	dst.put((byte)(0xe0 \| ((c >> 12))));
	dst.put((byte)(0x80 \| ((c >> 6) & 0x3f)));
	dst.put((byte)(0x80 \| (c & 0x3f)));
	}
	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);
	}

	}
	}

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