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	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.sun.org.apache.xerces.internal.impl.io;

	import java.io.InputStream;
	import java.io.IOException;
	import java.io.Reader;

	import java.util.Locale;
	import com.sun.org.apache.xerces.internal.util.MessageFormatter;
	import com.sun.org.apache.xerces.internal.impl.msg.XMLMessageFormatter;

	import com.sun.xml.internal.stream.util.BufferAllocator;
	import com.sun.xml.internal.stream.util.ThreadLocalBufferAllocator;

	/**
	* <p>A UTF-8 reader.</p>
	*
	* @xerces.internal
	*
	* @author Andy Clark, IBM
	*
	*/
	public class UTF8Reader
	extends Reader {

	//
	// Constants
	//

	/** Default byte buffer size (2048). */
	public static final int DEFAULT_BUFFER_SIZE = 2048;

	// debugging

	/** Debug read. */
	private static final boolean DEBUG_READ = false;

	//
	// Data
	//

	/** Input stream. */
	protected InputStream fInputStream;

	/** Byte buffer. */
	protected byte[] fBuffer;

	/** Offset into buffer. */
	protected int fOffset;

	/** Surrogate character. */
	private int fSurrogate = -1;

	// message formatter; used to produce localized
	// exception messages
	private MessageFormatter fFormatter = null;

	//Locale to use for messages
	private Locale fLocale = null;

	//
	// Constructors
	//

	/**
	* Constructs a UTF-8 reader from the specified input stream
	* using the default buffer size. Primarily for testing.
	*
	* @param inputStream The input stream.
	*/
	public UTF8Reader(InputStream inputStream) {
	this(inputStream, DEFAULT_BUFFER_SIZE, new XMLMessageFormatter(), Locale.getDefault());
	} // <init>(InputStream, MessageFormatter)

	/**
	* Constructs a UTF-8 reader from the specified input stream
	* using the default buffer size and the given MessageFormatter.
	*
	* @param inputStream The input stream.
	* @param messageFormatter given MessageFormatter
	* @param locale Locale to use for messages
	*/
	public UTF8Reader(InputStream inputStream, MessageFormatter messageFormatter,
	Locale locale) {
	this(inputStream, DEFAULT_BUFFER_SIZE, messageFormatter, locale);
	} // <init>(InputStream, MessageFormatter, Locale)

	/**
	* Constructs a UTF-8 reader from the specified input stream,
	* buffer size and MessageFormatter.
	*
	* @param inputStream The input stream.
	* @param size The initial buffer size.
	* @param messageFormatter the formatter for localizing/formatting errors.
	* @param locale the Locale to use for messages
	*/
	public UTF8Reader(InputStream inputStream, int size,
	MessageFormatter messageFormatter, Locale locale) {
	fInputStream = inputStream;
	BufferAllocator ba = ThreadLocalBufferAllocator.getBufferAllocator();
	fBuffer = ba.getByteBuffer(size);
	if (fBuffer == null) {
	fBuffer = new byte[size];
	}
	fFormatter = messageFormatter;
	fLocale = locale;
	} // <init>(InputStream, int, MessageFormatter, Locale)

	//
	// Reader methods
	//

	/**
	* Read a single character. This method will block until a character is
	* available, an I/O error occurs, or the end of the stream is reached.
	*
	* <p> Subclasses that intend to support efficient single-character input
	* should override this method.
	*
	* @return The character read, as an integer in the range 0 to 16383
	* (<tt>0x00-0xffff</tt>), or -1 if the end of the stream has
	* been reached
	*
	* @exception IOException If an I/O error occurs
	*/
	public int read() throws IOException {

	// decode character
	int c = fSurrogate;
	if (fSurrogate == -1) {
	// NOTE: We use the index into the buffer if there are remaining
	// bytes from the last block read. -Ac
	int index = 0;

	// get first byte
	int b0 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b0 == -1) {
	return -1;
	}

	// UTF-8: [0xxx xxxx]
	// Unicode: [0000 0000] [0xxx xxxx]
	if (b0 < 0x80) {
	c = (char)b0;
	}

	// UTF-8: [110y yyyy] [10xx xxxx]
	// Unicode: [0000 0yyy] [yyxx xxxx]
	else if ((b0 & 0xE0) == 0xC0 && (b0 & 0x1E) != 0) {
	int b1 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b1 == -1) {
	expectedByte(2, 2);
	}
	if ((b1 & 0xC0) != 0x80) {
	invalidByte(2, 2, b1);
	}
	c = ((b0 << 6) & 0x07C0) \| (b1 & 0x003F);
	}

	// UTF-8: [1110 zzzz] [10yy yyyy] [10xx xxxx]
	// Unicode: [zzzz yyyy] [yyxx xxxx]
	else if ((b0 & 0xF0) == 0xE0) {
	int b1 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b1 == -1) {
	expectedByte(2, 3);
	}
	if ((b1 & 0xC0) != 0x80
	\|\| (b0 == 0xED && b1 >= 0xA0)
	\|\| ((b0 & 0x0F) == 0 && (b1 & 0x20) == 0)) {
	invalidByte(2, 3, b1);
	}
	int b2 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b2 == -1) {
	expectedByte(3, 3);
	}
	if ((b2 & 0xC0) != 0x80) {
	invalidByte(3, 3, b2);
	}
	c = ((b0 << 12) & 0xF000) \| ((b1 << 6) & 0x0FC0) \|
	(b2 & 0x003F);
	}

	// UTF-8: [1111 0uuu] [10uu zzzz] [10yy yyyy] [10xx xxxx]*
	// Unicode: [1101 10ww] [wwzz zzyy] (high surrogate)
	// [1101 11yy] [yyxx xxxx] (low surrogate)
	// * uuuuu = wwww + 1
	else if ((b0 & 0xF8) == 0xF0) {
	int b1 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b1 == -1) {
	expectedByte(2, 4);
	}
	if ((b1 & 0xC0) != 0x80
	\|\| ((b1 & 0x30) == 0 && (b0 & 0x07) == 0)) {
	invalidByte(2, 3, b1);
	}
	int b2 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b2 == -1) {
	expectedByte(3, 4);
	}
	if ((b2 & 0xC0) != 0x80) {
	invalidByte(3, 3, b2);
	}
	int b3 = index == fOffset
	? fInputStream.read() : fBuffer[index++] & 0x00FF;
	if (b3 == -1) {
	expectedByte(4, 4);
	}
	if ((b3 & 0xC0) != 0x80) {
	invalidByte(4, 4, b3);
	}
	int uuuuu = ((b0 << 2) & 0x001C) \| ((b1 >> 4) & 0x0003);
	if (uuuuu > 0x10) {
	invalidSurrogate(uuuuu);
	}
	int wwww = uuuuu - 1;
	int hs = 0xD800 \|
	((wwww << 6) & 0x03C0) \| ((b1 << 2) & 0x003C) \|
	((b2 >> 4) & 0x0003);
	int ls = 0xDC00 \| ((b2 << 6) & 0x03C0) \| (b3 & 0x003F);
	c = hs;
	fSurrogate = ls;
	}

	// error
	else {
	invalidByte(1, 1, b0);
	}
	}

	// use surrogate
	else {
	fSurrogate = -1;
	}

	// return character
	if (DEBUG_READ) {
	System.out.println("read(): 0x"+Integer.toHexString(c));
	}
	return c;

	} // read():int

	/**
	* Read characters into a portion of an array. This method will block
	* until some input is available, an I/O error occurs, or the end of the
	* stream is reached.
	*
	* @param ch Destination buffer
	* @param offset Offset at which to start storing characters
	* @param length Maximum number of characters to read
	*
	* @return The number of characters read, or -1 if the end of the
	* stream has been reached
	*
	* @exception IOException If an I/O error occurs
	*/
	public int read(char ch[], int offset, int length) throws IOException {

	// handle surrogate
	int out = offset;
	if (fSurrogate != -1) {
	ch[offset + 1] = (char)fSurrogate;
	fSurrogate = -1;
	length--;
	out++;
	}

	// read bytes
	int count = 0;
	if (fOffset == 0) {
	// adjust length to read
	if (length > fBuffer.length) {
	length = fBuffer.length;
	}

	// perform read operation
	count = fInputStream.read(fBuffer, 0, length);
	if (count == -1) {
	return -1;
	}
	count += out - offset;
	}

	// skip read; last character was in error
	// NOTE: Having an offset value other than zero means that there was
	// an error in the last character read. In this case, we have
	// skipped the read so we don't consume any bytes past the
	// error. By signalling the error on the next block read we
	// allow the method to return the most valid characters that
	// it can on the previous block read. -Ac
	else {
	count = fOffset;
	fOffset = 0;
	}

	// convert bytes to characters
	final int total = count;
	int in;
	byte byte1;
	final byte byte0 = 0;
	for (in = 0; in < total; in++) {
	byte1 = fBuffer[in];
	if (byte1 >= byte0) {
	ch[out++] = (char)byte1;
	}
	else {
	break;
	}
	}
	for ( ; in < total; in++) {
	byte1 = fBuffer[in];

	// UTF-8: [0xxx xxxx]
	// Unicode: [0000 0000] [0xxx xxxx]
	if (byte1 >= byte0) {
	ch[out++] = (char)byte1;
	continue;
	}

	// UTF-8: [110y yyyy] [10xx xxxx]
	// Unicode: [0000 0yyy] [yyxx xxxx]
	int b0 = byte1 & 0x0FF;
	if ((b0 & 0xE0) == 0xC0 && (b0 & 0x1E) != 0) {
	int b1 = -1;
	if (++in < total) {
	b1 = fBuffer[in] & 0x00FF;
	}
	else {
	b1 = fInputStream.read();
	if (b1 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fOffset = 1;
	return out - offset;
	}
	expectedByte(2, 2);
	}
	count++;
	}
	if ((b1 & 0xC0) != 0x80) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fOffset = 2;
	return out - offset;
	}
	invalidByte(2, 2, b1);
	}
	int c = ((b0 << 6) & 0x07C0) \| (b1 & 0x003F);
	ch[out++] = (char)c;
	count -= 1;
	continue;
	}

	// UTF-8: [1110 zzzz] [10yy yyyy] [10xx xxxx]
	// Unicode: [zzzz yyyy] [yyxx xxxx]
	if ((b0 & 0xF0) == 0xE0) {
	int b1 = -1;
	if (++in < total) {
	b1 = fBuffer[in] & 0x00FF;
	}
	else {
	b1 = fInputStream.read();
	if (b1 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fOffset = 1;
	return out - offset;
	}
	expectedByte(2, 3);
	}
	count++;
	}
	if ((b1 & 0xC0) != 0x80
	\|\| (b0 == 0xED && b1 >= 0xA0)
	\|\| ((b0 & 0x0F) == 0 && (b1 & 0x20) == 0)) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fOffset = 2;
	return out - offset;
	}
	invalidByte(2, 3, b1);
	}
	int b2 = -1;
	if (++in < total) {
	b2 = fBuffer[in] & 0x00FF;
	}
	else {
	b2 = fInputStream.read();
	if (b2 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fOffset = 2;
	return out - offset;
	}
	expectedByte(3, 3);
	}
	count++;
	}
	if ((b2 & 0xC0) != 0x80) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fBuffer[2] = (byte)b2;
	fOffset = 3;
	return out - offset;
	}
	invalidByte(3, 3, b2);
	}
	int c = ((b0 << 12) & 0xF000) \| ((b1 << 6) & 0x0FC0) \|
	(b2 & 0x003F);
	ch[out++] = (char)c;
	count -= 2;
	continue;
	}

	// UTF-8: [1111 0uuu] [10uu zzzz] [10yy yyyy] [10xx xxxx]*
	// Unicode: [1101 10ww] [wwzz zzyy] (high surrogate)
	// [1101 11yy] [yyxx xxxx] (low surrogate)
	// * uuuuu = wwww + 1
	if ((b0 & 0xF8) == 0xF0) {
	int b1 = -1;
	if (++in < total) {
	b1 = fBuffer[in] & 0x00FF;
	}
	else {
	b1 = fInputStream.read();
	if (b1 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fOffset = 1;
	return out - offset;
	}
	expectedByte(2, 4);
	}
	count++;
	}
	if ((b1 & 0xC0) != 0x80
	\|\| ((b1 & 0x30) == 0 && (b0 & 0x07) == 0)) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fOffset = 2;
	return out - offset;
	}
	invalidByte(2, 4, b1);
	}
	int b2 = -1;
	if (++in < total) {
	b2 = fBuffer[in] & 0x00FF;
	}
	else {
	b2 = fInputStream.read();
	if (b2 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fOffset = 2;
	return out - offset;
	}
	expectedByte(3, 4);
	}
	count++;
	}
	if ((b2 & 0xC0) != 0x80) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fBuffer[2] = (byte)b2;
	fOffset = 3;
	return out - offset;
	}
	invalidByte(3, 4, b2);
	}
	int b3 = -1;
	if (++in < total) {
	b3 = fBuffer[in] & 0x00FF;
	}
	else {
	b3 = fInputStream.read();
	if (b3 == -1) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fBuffer[2] = (byte)b2;
	fOffset = 3;
	return out - offset;
	}
	expectedByte(4, 4);
	}
	count++;
	}
	if ((b3 & 0xC0) != 0x80) {
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fBuffer[2] = (byte)b2;
	fBuffer[3] = (byte)b3;
	fOffset = 4;
	return out - offset;
	}
	invalidByte(4, 4, b2);
	}

	// check if output buffer is large enough to hold 2 surrogate chars
	if (out + 1 >= ch.length) {
	fBuffer[0] = (byte)b0;
	fBuffer[1] = (byte)b1;
	fBuffer[2] = (byte)b2;
	fBuffer[3] = (byte)b3;
	fOffset = 4;
	return out - offset;
	}

	// decode bytes into surrogate characters
	int uuuuu = ((b0 << 2) & 0x001C) \| ((b1 >> 4) & 0x0003);
	if (uuuuu > 0x10) {
	invalidSurrogate(uuuuu);
	}
	int wwww = uuuuu - 1;
	int zzzz = b1 & 0x000F;
	int yyyyyy = b2 & 0x003F;
	int xxxxxx = b3 & 0x003F;
	int hs = 0xD800 \| ((wwww << 6) & 0x03C0) \| (zzzz << 2) \| (yyyyyy >> 4);
	int ls = 0xDC00 \| ((yyyyyy << 6) & 0x03C0) \| xxxxxx;

	// set characters
	ch[out++] = (char)hs;
	ch[out++] = (char)ls;
	count -= 2;
	continue;
	}

	// error
	if (out > offset) {
	fBuffer[0] = (byte)b0;
	fOffset = 1;
	return out - offset;
	}
	invalidByte(1, 1, b0);
	}

	// return number of characters converted
	if (DEBUG_READ) {
	System.out.println("read(char[],"+offset+','+length+"): count="+count);
	}
	return count;

	} // read(char[],int,int)

	/**
	* Skip characters. This method will block until some characters are
	* available, an I/O error occurs, or the end of the stream is reached.
	*
	* @param n The number of characters to skip
	*
	* @return The number of characters actually skipped
	*
	* @exception IOException If an I/O error occurs
	*/
	public long skip(long n) throws IOException {

	long remaining = n;
	final char[] ch = new char[fBuffer.length];
	do {
	int length = ch.length < remaining ? ch.length : (int)remaining;
	int count = read(ch, 0, length);
	if (count > 0) {
	remaining -= count;
	}
	else {
	break;
	}
	} while (remaining > 0);

	long skipped = n - remaining;
	return skipped;

	} // skip(long):long

	/**
	* Tell whether this stream is ready to be read.
	*
	* @return True if the next read() is guaranteed not to block for input,
	* false otherwise. Note that returning false does not guarantee that the
	* next read will block.
	*
	* @exception IOException If an I/O error occurs
	*/
	public boolean ready() throws IOException {
	return false;
	} // ready()

	/**
	* Tell whether this stream supports the mark() operation.
	*/
	public boolean markSupported() {
	return false;
	} // markSupported()

	/**
	* Mark the present position in the stream. Subsequent calls to reset()
	* will attempt to reposition the stream to this point. Not all
	* character-input streams support the mark() operation.
	*
	* @param readAheadLimit Limit on the number of characters that may be
	* read while still preserving the mark. After
	* reading this many characters, attempting to
	* reset the stream may fail.
	*
	* @exception IOException If the stream does not support mark(),
	* or if some other I/O error occurs
	*/
	public void mark(int readAheadLimit) throws IOException {
	throw new IOException(fFormatter.formatMessage(fLocale, "OperationNotSupported", new Object[]{"mark()", "UTF-8"}));
	} // mark(int)

	/**
	* Reset the stream. If the stream has been marked, then attempt to
	* reposition it at the mark. If the stream has not been marked, then
	* attempt to reset it in some way appropriate to the particular stream,
	* for example by repositioning it to its starting point. Not all
	* character-input streams support the reset() operation, and some support
	* reset() without supporting mark().
	*
	* @exception IOException If the stream has not been marked,
	* or if the mark has been invalidated,
	* or if the stream does not support reset(),
	* or if some other I/O error occurs
	*/
	public void reset() throws IOException {
	fOffset = 0;
	fSurrogate = -1;
	} // reset()

	/**
	* Close the stream. Once a stream has been closed, further read(),
	* ready(), mark(), or reset() invocations will throw an IOException.
	* Closing a previously-closed stream, however, has no effect.
	*
	* @exception IOException If an I/O error occurs
	*/
	public void close() throws IOException {
	BufferAllocator ba = ThreadLocalBufferAllocator.getBufferAllocator();
	ba.returnByteBuffer(fBuffer);
	fBuffer = null;
	fInputStream.close();
	} // close()

	//
	// Private methods
	//

	/** Throws an exception for expected byte. */
	private void expectedByte(int position, int count)
	throws MalformedByteSequenceException {

	throw new MalformedByteSequenceException(fFormatter,
	fLocale,
	XMLMessageFormatter.XML_DOMAIN,
	"ExpectedByte",
	new Object[] {Integer.toString(position), Integer.toString(count)});

	} // expectedByte(int,int)

	/** Throws an exception for invalid byte. */
	private void invalidByte(int position, int count, int c)
	throws MalformedByteSequenceException {

	throw new MalformedByteSequenceException(fFormatter,
	fLocale,
	XMLMessageFormatter.XML_DOMAIN,
	"InvalidByte",
	new Object [] {Integer.toString(position), Integer.toString(count)});

	} // invalidByte(int,int,int)

	/** Throws an exception for invalid surrogate bits. */
	private void invalidSurrogate(int uuuuu) throws MalformedByteSequenceException {

	throw new MalformedByteSequenceException(fFormatter,
	fLocale,
	XMLMessageFormatter.XML_DOMAIN,
	"InvalidHighSurrogate",
	new Object[] {Integer.toHexString(uuuuu)});

	} // invalidSurrogate(int)

	} // class UTF8Reader

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