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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.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;

	public class US_ASCII
	extends Charset
	implements HistoricallyNamedCharset
	{
	public static final US_ASCII INSTANCE = new US_ASCII();

	public US_ASCII() {
	super("US-ASCII", StandardCharsets.aliases_US_ASCII());
	}

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

	public boolean contains(Charset cs) {
	return (cs instanceof US_ASCII);
	}

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

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

	private static class Decoder extends CharsetDecoder {

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

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

	private CoderResult decodeArrayLoop(ByteBuffer src,
	CharBuffer dst)
	{
	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();

	// ASCII only loop
	int n = JLA.decodeASCII(sa, sp, da, dp, Math.min(sl - sp, dl - dp));
	sp += n;
	dp += n;
	src.position(sp - soff);
	dst.position(dp - doff);
	if (sp < sl) {
	if (dp >= dl) {
	return CoderResult.OVERFLOW;
	}
	return CoderResult.malformedForLength(1);
	}
	return CoderResult.UNDERFLOW;
	}

	private CoderResult decodeBufferLoop(ByteBuffer src,
	CharBuffer dst)
	{
	int mark = src.position();
	try {
	while (src.hasRemaining()) {
	byte b = src.get();
	if (b >= 0) {
	if (!dst.hasRemaining())
	return CoderResult.OVERFLOW;
	dst.put((char)b);
	mark++;
	continue;
	}
	return CoderResult.malformedForLength(1);
	}
	return CoderResult.UNDERFLOW;
	} finally {
	src.position(mark);
	}
	}

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

	private static class Encoder extends CharsetEncoder {

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

	public boolean canEncode(char c) {
	return c < 0x80;
	}

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

	private final Surrogate.Parser sgp = new Surrogate.Parser();
	private CoderResult encodeArrayLoop(CharBuffer src,
	ByteBuffer dst)
	{
	char[] sa = src.array();
	int sp = src.arrayOffset() + src.position();
	int sl = src.arrayOffset() + src.limit();
	assert (sp <= sl);
	sp = (sp <= sl ? sp : sl);
	byte[] da = dst.array();
	int dp = dst.arrayOffset() + dst.position();
	int dl = dst.arrayOffset() + dst.limit();
	assert (dp <= dl);
	dp = (dp <= dl ? dp : dl);

	try {
	while (sp < sl) {
	char c = sa[sp];
	if (c < 0x80) {
	if (dp >= dl)
	return CoderResult.OVERFLOW;
	da[dp] = (byte)c;
	sp++; dp++;
	continue;
	}
	if (sgp.parse(c, sa, sp, sl) < 0)
	return sgp.error();
	return sgp.unmappableResult();
	}
	return CoderResult.UNDERFLOW;
	} finally {
	src.position(sp - src.arrayOffset());
	dst.position(dp - dst.arrayOffset());
	}
	}

	private CoderResult encodeBufferLoop(CharBuffer src,
	ByteBuffer dst)
	{
	int mark = src.position();
	try {
	while (src.hasRemaining()) {
	char c = src.get();
	if (c < 0x80) {
	if (!dst.hasRemaining())
	return CoderResult.OVERFLOW;
	dst.put((byte)c);
	mark++;
	continue;
	}
	if (sgp.parse(c, src) < 0)
	return sgp.error();
	return sgp.unmappableResult();
	}
	return CoderResult.UNDERFLOW;
	} finally {
	src.position(mark);
	}
	}

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

	}
	}

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