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

	/**
	* Reader for UCS-2 and UCS-4 encodings.
	* (i.e., encodings from ISO-10646-UCS-(2\|4)).
	*
	* @xerces.internal
	*
	* @author Neil Graham, IBM
	*
	*/
	public class UCSReader extends Reader {

	//
	// Constants
	//

	/** Default byte buffer size (8192, larger than that of ASCIIReader
	* since it's reasonable to surmise that the average UCS-4-encoded
	* file should be 4 times as large as the average ASCII-encoded file).
	*/
	public static final int DEFAULT_BUFFER_SIZE = 8192;

	public static final short UCS2LE = 1;
	public static final short UCS2BE = 2;
	public static final short UCS4LE = 4;
	public static final short UCS4BE = 8;

	//
	// Data
	//

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

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

	// what kind of data we're dealing with
	protected short fEncoding;

	//
	// Constructors
	//

	/**
	* Constructs an ASCII reader from the specified input stream
	* using the default buffer size. The Endian-ness and whether this is
	* UCS-2 or UCS-4 needs also to be known in advance.
	*
	* @param inputStream The input stream.
	* @param encoding One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.
	*/
	public UCSReader(InputStream inputStream, short encoding) {
	this(inputStream, DEFAULT_BUFFER_SIZE, encoding);
	} // <init>(InputStream, short)

	/**
	* Constructs an ASCII reader from the specified input stream
	* and buffer size. The Endian-ness and whether this is
	* UCS-2 or UCS-4 needs also to be known in advance.
	*
	* @param inputStream The input stream.
	* @param size The initial buffer size.
	* @param encoding One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.
	*/
	public UCSReader(InputStream inputStream, int size, short encoding) {
	fInputStream = inputStream;
	BufferAllocator ba = ThreadLocalBufferAllocator.getBufferAllocator();
	fBuffer = ba.getByteBuffer(size);
	if (fBuffer == null) {
	fBuffer = new byte[size];
	}
	fEncoding = encoding;
	} // <init>(InputStream,int,short)

	//
	// 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() & 0xff;
	if (b0 == 0xff)
	return -1;
	int b1 = fInputStream.read() & 0xff;
	if (b1 == 0xff)
	return -1;
	if(fEncoding >=4) {
	int b2 = fInputStream.read() & 0xff;
	if (b2 == 0xff)
	return -1;
	int b3 = fInputStream.read() & 0xff;
	if (b3 == 0xff)
	return -1;
	System.err.println("b0 is " + (b0 & 0xff) + " b1 " + (b1 & 0xff) + " b2 " + (b2 & 0xff) + " b3 " + (b3 & 0xff));
	if (fEncoding == UCS4BE)
	return (b0<<24)+(b1<<16)+(b2<<8)+b3;
	else
	return (b3<<24)+(b2<<16)+(b1<<8)+b0;
	} else { // UCS-2
	if (fEncoding == UCS2BE)
	return (b0<<8)+b1;
	else
	return (b1<<8)+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 {
	int byteLength = length << ((fEncoding >= 4)?2:1);
	if (byteLength > fBuffer.length) {
	byteLength = fBuffer.length;
	}
	int count = fInputStream.read(fBuffer, 0, byteLength);
	if(count == -1) return -1;
	// try and make count be a multiple of the number of bytes we're looking for
	if(fEncoding >= 4) { // BigEndian
	// this looks ugly, but it avoids an if at any rate...
	int numToRead = (4 - (count & 3) & 3);
	for(int i=0; i<numToRead; i++) {
	int charRead = fInputStream.read();
	if(charRead == -1) { // end of input; something likely went wrong!A Pad buffer with nulls.
	for (int j = i;j<numToRead; j++)
	fBuffer[count+j] = 0;
	break;
	} else {
	fBuffer[count+i] = (byte)charRead;
	}
	}
	count += numToRead;
	} else {
	int numToRead = count & 1;
	if(numToRead != 0) {
	count++;
	int charRead = fInputStream.read();
	if(charRead == -1) { // end of input; something likely went wrong!A Pad buffer with nulls.
	fBuffer[count] = 0;
	} else {
	fBuffer[count] = (byte)charRead;
	}
	}
	}

	// now count is a multiple of the right number of bytes
	int numChars = count >> ((fEncoding >= 4)?2:1);
	int curPos = 0;
	for (int i = 0; i < numChars; i++) {
	int b0 = fBuffer[curPos++] & 0xff;
	int b1 = fBuffer[curPos++] & 0xff;
	if(fEncoding >=4) {
	int b2 = fBuffer[curPos++] & 0xff;
	int b3 = fBuffer[curPos++] & 0xff;
	if (fEncoding == UCS4BE)
	ch[offset+i] = (char)((b0<<24)+(b1<<16)+(b2<<8)+b3);
	else
	ch[offset+i] = (char)((b3<<24)+(b2<<16)+(b1<<8)+b0);
	} else { // UCS-2
	if (fEncoding == UCS2BE)
	ch[offset+i] = (char)((b0<<8)+b1);
	else
	ch[offset+i] = (char)((b1<<8)+b0);
	}
	}
	return numChars;
	} // 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 {
	// charWidth will represent the number of bits to move
	// n leftward to get num of bytes to skip, and then move the result rightward
	// to get num of chars effectively skipped.
	// The trick with &'ing, as with elsewhere in this dcode, is
	// intended to avoid an expensive use of / that might not be optimized
	// away.
	int charWidth = (fEncoding >=4)?2:1;
	long bytesSkipped = fInputStream.skip(n<<charWidth);
	if((bytesSkipped & (charWidth \| 1)) == 0) return bytesSkipped >> charWidth;
	return (bytesSkipped >> charWidth) + 1;
	} // 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 UCSReader

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