src/org/apache/xerces/impl/io/ASCIIReader.java - xerces2-j - Git at Google

 /*
  * The Apache Software License, Version 1.1
  *
  *
  * Copyright (c) 2000 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. The end-user documentation included with the redistribution,
  *    if any, must include the following acknowledgment:
  *       "This product includes software developed by the
  *        Apache Software Foundation (http://www.apache.org/)."
  *    Alternately, this acknowledgment may appear in the software itself,
  *    if and wherever such third-party acknowledgments normally appear.
  *
  * 4. The names "Xerces" and "Apache Software Foundation" must
  *    not be used to endorse or promote products derived from this
  *    software without prior written permission. For written
  *    permission, please contact apache@apache.org.
  *
  * 5. Products derived from this software may not be called "Apache",
  *    nor may "Apache" appear in their name, without prior written
  *    permission of the Apache Software Foundation.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  * ====================================================================
  *
  * This software consists of voluntary contributions made by many
  * individuals on behalf of the Apache Software Foundation and was
  * originally based on software copyright (c) 1999, International
  * Business Machines, Inc., http://www.apache.org.  For more
  * information on the Apache Software Foundation, please see
  * <http://www.apache.org/>.
  */

 package org.apache.xerces.impl.io;

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

 /**
  * A simple ASCII byte reader. This is an optimized reader for reading
  * byte streams that only contain 7-bit ASCII characters.
  *
  * @author Andy Clark, IBM
  *
  * @version $Id$
  */
 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;

     //
     // Constructors
     //

     /**
      * Constructs an ASCII reader from the specified input stream
      * using the default buffer size.
      *
      * @param inputStream The input stream.
      */
     public ASCIIReader(InputStream inputStream) {
         this(inputStream, DEFAULT_BUFFER_SIZE);
     } // <init>(InputStream)

     /**
      * Constructs an ASCII reader from the specified input stream
      * and buffer size.
      *
      * @param inputStream The input stream.
      * @param size        The initial buffer size.
      */
     public ASCIIReader(InputStream inputStream, int size) {
         fInputStream = inputStream;
         fBuffer = new byte[size];
     } // <init>(InputStream,int)

     //
     // 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 IOException("character not 7-bit ASCII");
         }
         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 > 0x80) {
                 throw new IOException("character not 7-bit ASCII");
             }
             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 {
          fInputStream.close();
      } // close()

 } // class ASCIIReader
	/*
	* The Apache Software License, Version 1.1
	*
	*
	* Copyright (c) 2000 The Apache Software Foundation. All rights
	* reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. The end-user documentation included with the redistribution,
	* if any, must include the following acknowledgment:
	* "This product includes software developed by the
	* Apache Software Foundation (http://www.apache.org/)."
	* Alternately, this acknowledgment may appear in the software itself,
	* if and wherever such third-party acknowledgments normally appear.
	*
	* 4. The names "Xerces" and "Apache Software Foundation" must
	* not be used to endorse or promote products derived from this
	* software without prior written permission. For written
	* permission, please contact apache@apache.org.
	*
	* 5. Products derived from this software may not be called "Apache",
	* nor may "Apache" appear in their name, without prior written
	* permission of the Apache Software Foundation.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	* ====================================================================
	*
	* This software consists of voluntary contributions made by many
	* individuals on behalf of the Apache Software Foundation and was
	* originally based on software copyright (c) 1999, International
	* Business Machines, Inc., http://www.apache.org. For more
	* information on the Apache Software Foundation, please see
	* <http://www.apache.org/>.
	*/

	package org.apache.xerces.impl.io;

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

	/**
	* A simple ASCII byte reader. This is an optimized reader for reading
	* byte streams that only contain 7-bit ASCII characters.
	*
	* @author Andy Clark, IBM
	*
	* @version $Id$
	*/
	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;

	//
	// Constructors
	//

	/**
	* Constructs an ASCII reader from the specified input stream
	* using the default buffer size.
	*
	* @param inputStream The input stream.
	*/
	public ASCIIReader(InputStream inputStream) {
	this(inputStream, DEFAULT_BUFFER_SIZE);
	} // <init>(InputStream)

	/**
	* Constructs an ASCII reader from the specified input stream
	* and buffer size.
	*
	* @param inputStream The input stream.
	* @param size The initial buffer size.
	*/
	public ASCIIReader(InputStream inputStream, int size) {
	fInputStream = inputStream;
	fBuffer = new byte[size];
	} // <init>(InputStream,int)

	//
	// 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 IOException("character not 7-bit ASCII");
	}
	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 > 0x80) {
	throw new IOException("character not 7-bit ASCII");
	}
	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 {
	fInputStream.close();
	} // close()

	} // class ASCIIReader