src.it.unimi.dsi.bits.TransformationStrategy Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of dsiutils Show documentation

The DSI utilities are a mishmash of classes accumulated during the last twenty years in projects developed at the DSI (Dipartimento di Scienze dell'Informazione, i.e., Information Sciences Department), now DI (Dipartimento di Informatica, i.e., Informatics Department), of the Universita` degli Studi di Milano.

There is a newer version: 2.7.3

Show newest version

package it.unimi.dsi.bits;

/*
 * DSI utilities
 *
 * Copyright (C) 2007-2020 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 3 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, see .
 *
 */

import java.io.Serializable;

/** A generic transformation from objects of a given type to bit vector. Most useful
 * when adding strings, etc. to a trie.
 */

public interface TransformationStrategy extends Serializable {
	/** Returns a bit vector representation of the given object.
	 *
	 * @param object the object to be turned into a bit-vector representation.
	 * @return a bit-vector representation of object.
	 */
	BitVector toBitVector(T object);

	/** The (approximate) number of bits occupied by this transformation.
	 *
	 * @return the (approximate) number of bits occupied by this transformation.
	 */
	long numBits();

	/** Returns a copy of this transformation strategy.
	 *
	 * @return a copy of this transformation strategy.
	 */
	TransformationStrategy copy();

	/** Returns the length of the bit vector that would be computed by {@link #toBitVector(Object)}.
	 *
	 * The raison d'être of this method is that it is often easy to know
	 * the length of the representation without actually computing the representation.
	 *
	 * @param object the object whose representation length is to be known.
	 * @return the length of the bit-vector representation of object (the one that would be returned by {@link #toBitVector(Object)}).
	 */
	long length(T object);
}