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package it.unimi.dsi.util;
/*
* DSI utilities
*
* Copyright (C) 2007-2009 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.objects.AbstractObject2LongFunction;
import it.unimi.dsi.fastutil.objects.AbstractObject2ObjectFunction;
import it.unimi.dsi.fastutil.objects.AbstractObjectList;
import it.unimi.dsi.fastutil.objects.Object2ObjectFunction;
import it.unimi.dsi.fastutil.objects.ObjectList;
import it.unimi.dsi.lang.MutableString;
import java.io.Serializable;
/** An abstract implementation of a prefix map.
*
* This class provides the full serives of a {@link PrefixMap} by implementing just
* {@link #getInterval(CharSequence)} and {@link #getTerm(int, MutableString)}
*/
public abstract class AbstractPrefixMap extends AbstractObject2LongFunction implements PrefixMap, Serializable {
private static final long serialVersionUID = 1L;
protected Object2ObjectFunction rangeMap;
protected Object2ObjectFunction prefixMap;
protected ObjectList list;
// We must guarantee that, unless the user says otherwise, the default return value is -1.
{
defaultReturnValue( -1 );
}
/** Returns the range of strings having a given prefix.
*
* @param prefix a prefix.
* @return the corresponding range of strings as an interval.
*/
protected abstract Interval getInterval( CharSequence prefix );
/** Writes a string specified by index into a {@link MutableString}.
*
* @param index the index of a string.
* @param string a mutable string.
* @return string.
*/
protected abstract MutableString getTerm( int index, MutableString string );
public Object2ObjectFunction rangeMap() {
if ( rangeMap == null ) rangeMap = new AbstractObject2ObjectFunction() {
private static final long serialVersionUID = 1L;
public boolean containsKey( final Object o ) {
return get( o ) != Intervals.EMPTY_INTERVAL;
}
public int size() {
return -1;
}
public Interval get( final Object o ) {
return getInterval( (CharSequence)o );
}
};
return rangeMap;
}
public Object2ObjectFunction prefixMap() {
if ( prefixMap == null ) prefixMap = new AbstractObject2ObjectFunction() {
private static final long serialVersionUID = 1L;
public MutableString get( final Object o ) {
final Interval interval = (Interval)o;
final MutableString prefix = new MutableString();
if ( interval == Intervals.EMPTY_INTERVAL || interval.left < 0 || interval.right < 0 ) throw new IllegalArgumentException();
getTerm( interval.left, prefix );
if ( interval.length() == 1 ) return prefix;
final MutableString s = getTerm( interval.right, new MutableString() );
final int l = Math.min( prefix.length(), s.length() );
int i;
for( i = 0; i < l; i++ ) if ( s.charAt( i ) != prefix.charAt( i ) ) break;
return prefix.length( i );
}
public boolean containsKey( final Object o ) {
Interval interval = (Interval)o;
return interval != Intervals.EMPTY_INTERVAL && interval.left >= 0 && interval.right < AbstractPrefixMap.this.size();
}
public int size() {
return -1;
}
};
return prefixMap;
}
public ObjectList list() {
if ( list == null ) list = new AbstractObjectList() {
public int size() {
return AbstractPrefixMap.this.size();
}
public MutableString get( int index ) {
return getTerm( index, new MutableString() );
}
};
return list;
}
}