/* * (c) Copyright 2010 Epimorphics Ltd. * All rights reserved. * [See end of file] */ package storage; import java.nio.LongBuffer ; import com.hp.hpl.jena.tdb.base.StorageException ; /* Maps long to long */ public class Indirection { private Sequence seq ; private LongBuffer buffer = LongBuffer.allocate(1000) ; public Indirection() { } public long get(long ref) { check(ref) ; return _get(ref) ; } private long _get(long ref) { int x = (int)ref ; return buffer.get(x) ; } /** Store the value, return the reference to it */ public long map(long value) { int x = (int)seq.next() ; if ( x > buffer.limit() ) buffer = realloc() ; buffer.put(x, value) ; return x ; } protected LongBuffer realloc() { LongBuffer buffer2 = LongBuffer.allocate(buffer.capacity()*2) ; buffer.position(0) ; buffer.limit(buffer.capacity()) ; buffer2.put(buffer) ; return buffer2 ; } /** Alter an existing mapping. Return the old value */ public long remap(long ref, long newValue) { check(ref) ; long oldValue = _get(ref) ; int x = (int)seq.next() ; _put(x, newValue) ; return oldValue ; } private void _put(long ref, long newValue) { int x = (int)ref ; buffer.put(x, newValue) ; } private void check(long ref) { if ( ref < 0 || ref > seq.readLast() ) throw new StorageException("Reference out of range: "+ref+" : [0,"+seq.readLast()+"]") ; } } /* * (c) Copyright 2010 Epimorphics Ltd. * 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 name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 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 AUTHOR 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. */