[cweb-CVS] lgpl-utils/src/java/it/unimi/dsi/mg4j/io NullInputStream.java, NONE, 1.1 OutputBitStream.java, NONE, 1.1 InputBitStream.java, NONE, 1.1

[Bryan T. <tho...@us...>]

Update of /cvsroot/cweb/lgpl-utils/src/java/it/unimi/dsi/mg4j/io
In directory sc8-pr-cvs4.sourceforge.net:/tmp/cvs-serv14570/src/java/it/unimi/dsi/mg4j/io

Added Files:
	NullInputStream.java OutputBitStream.java InputBitStream.java 
Log Message:
Commit incorporates some clases from the mg4j project that I am trying out for order preserving (alphabetic) compression.  I am in the process of writing test cases for the HuTuckerCodec that verify its use and order preserving properties.  A minimal set of classes from mg4j has been imported to support compression.  A fastutils jar has also been incorporated, but it can doubtless be prunned down even further.  The import is from the 1.x version of mg4j.  I should really re-import from 2.0 now that it has been released.

--- NEW FILE: NullInputStream.java ---
package it.unimi.dsi.mg4j.io;

/*		 
 * MG4J: Managing Gigabytes for Java
 *
 * Copyright (C) 2003-2006 Sebastiano Vigna 
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 2.1 of the License, or (at your option)
 *  any later version.
 *
 *  This library 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 Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

import it.unimi.dsi.fastutil.io.MeasurableInputStream;
import it.unimi.dsi.fastutil.io.RepositionableStream;

import java.io.IOException;
import java.io.Serializable;

/** End-of-stream-only input stream.
 *
 * <P>This stream has length 0, and will always return end-of-file on any read attempt.
 *
 * <P>This class is a singleton. You cannot create a null input stream,
 * but you can obtain an instance of this class using {@link #getInstance()}.
 *
 * @author Sebastiano Vigna
 * @since 0.8
 */

public class NullInputStream extends MeasurableInputStream implements RepositionableStream, Serializable {
	private static final long serialVersionUID = 1L;
	private final static NullInputStream INSTANCE = new NullInputStream();

	private NullInputStream() {}
	 
	public int read() { return -1; }

	/** Returns the only instance of this class.
	 * 
	 * @return  the only instance of this class.
	 */
	public static NullInputStream getInstance() {
		return INSTANCE;
	}

	private Object readResolve() {
		return INSTANCE;
	}

	@Override
	public long length() {
		return 0;
	}

	@Override
	public long position() {
		return 0;
	}

	public void position( long position ) throws IOException {
		// TODO: we should specify the semantics out of bounds
		return;
	}
}

--- NEW FILE: OutputBitStream.java ---
package it.unimi.dsi.mg4j.io;

/*		 
* MG4J: Managing Gigabytes for Java
*
* Copyright (C) 2002-2006 Sebastiano Vigna 
*
*  This library is free software; you can redistribute it and/or modify it
*  under the terms of the GNU Lesser General Public License as published by the Free
*  Software Foundation; either version 2.1 of the License, or (at your option)
*  any later version.
*
*  This library 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 Lesser General Public License
*  for more details.
*
*  You should have received a copy of the GNU Lesser General Public License
*  along with this program; if not, write to the Free Software
[...1058 lines suppressed...]
	 *
	 * @param x a long natural number.
	 * @return the number of bits written.
	 * @throws IllegalArgumentException if you try to write a negative number.
	 */

	public int writeLongNibble( final long x ) throws IOException {
		if ( x < 0 ) throw new IllegalArgumentException( "The argument " + x + " is negative" );

		if ( x == 0 ) return writeInt( 8, 4 );
		final int msb = Fast.mostSignificantBit( x );
		int h = msb / 3;
		do {
			writeBit( h == 0 );
			writeInt( (int)( x >> h * 3 ) , 3 );
		} while( h-- != 0 );
		return ( ( msb / 3 ) + 1 ) << 2;
	}
	
}

--- NEW FILE: InputBitStream.java ---
package it.unimi.dsi.mg4j.io;

/*		 
* MG4J: Managing Gigabytes for Java
*
* Copyright (C) 2002-2006 Sebastiano Vigna 
*
*  This library is free software; you can redistribute it and/or modify it
*  under the terms of the GNU Lesser General Public License as published by the Free
*  Software Foundation; either version 2.1 of the License, or (at your option)
*  any later version.
*
*  This library 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 Lesser General Public License
*  for more details.
*
*  You should have received a copy of the GNU Lesser General Public License
*  along with this program; if not, write to the Free Software
[...1177 lines suppressed...]
		}
	}
	
	public Boolean next() {
		return Boolean.valueOf( nextBoolean() );
	}
	
	public void remove() {
		throw new UnsupportedOperationException();
	}
	
	public int skip( final int n ) {
		try {
			return (int)skip( (long)n );
		}
		catch ( IOException e ) {
			throw new RuntimeException( e );
		}
	}
}