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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;

	/**
	* A simple ASCII byte reader. This is an optimized reader for reading
	* byte streams that only contain 7-bit ASCII characters.
	*
	* @xerces.internal
	*
	* @author Andy Clark, IBM
	*
	*/
	public class ASCIIReader
	extends Reader {

	//
	// Constants
	//

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

	//
	// Data
	//

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

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

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

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

	//
	// Constructors
	//

	/**
	* Constructs an ASCII reader from the specified input stream
	* using the default buffer size.
	*
	* @param inputStream The input stream.
	* @param messageFormatter the MessageFormatter to use to message reporting.
	* @param locale the Locale for which messages are to be reported
	*/
	public ASCIIReader(InputStream inputStream, MessageFormatter messageFormatter,
	Locale locale) {
	this(inputStream, DEFAULT_BUFFER_SIZE, messageFormatter, locale);
	} // <init>(InputStream, MessageFormatter, Locale)

	/**
	* Constructs an ASCII reader from the specified input stream
	* and buffer size.
	*
	* @param inputStream The input stream.
	* @param size The initial buffer size.
	* @param messageFormatter the MessageFormatter to use to message reporting.
	* @param locale the Locale for which messages are to be reported
	*/
	public ASCIIReader(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 127
	* (<tt>0x00-0x7f</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 {
	int b0 = fInputStream.read();
	if (b0 >= 0x80) {
	throw new MalformedByteSequenceException(fFormatter,
	fLocale, XMLMessageFormatter.XML_DOMAIN,
	"InvalidASCII", new Object [] {Integer.toString(b0)});
	}
	return b0;
	} // 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 {
	if (length > fBuffer.length) {
	length = fBuffer.length;
	}
	int count = fInputStream.read(fBuffer, 0, length);
	for (int i = 0; i < count; i++) {
	int b0 = fBuffer[i];
	if (b0 < 0) {
	throw new MalformedByteSequenceException(fFormatter,
	fLocale, XMLMessageFormatter.XML_DOMAIN,
	"InvalidASCII", new Object [] {Integer.toString(b0 & 0x0FF)});
	}
	ch[offset + i] = (char)b0;
	}
	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 {
	return fInputStream.skip(n);
	} // 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 fInputStream.markSupported();
	} // 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 {
	fInputStream.mark(readAheadLimit);
	} // 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 {
	fInputStream.reset();
	} // 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()

	} // class ASCIIReader

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