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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.

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package it.unimi.dsi.compression;

/*
 * DSI utilities
 *
 * Copyright (C) 2005-2019 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 it.unimi.dsi.bits.BitVector;


/** A coder based on a set of prefix-free codewords.
 *
 * Not all coders are codeword-based (for instance, arithmetic coding
 * is not codeword-based). However, coders that are based on prefix-free codewords are invited
 * to return by means of {@link it.unimi.dsi.compression.Codec#coder()} an
 * implementation of this interface.
 *
 * Note that the {@linkplain PrefixCodec#coder() coder} returned by a {@link PrefixCodec} is
 * an implementation of this interface.
 */
public interface PrefixCoder extends Coder {

	/** Provides access to the codewords.
	 *
	 * Warning: bit 0 of each bit vector returned by {@link #codeWords()} is
	 * the first (leftmost) bit of the corresponding codeword: in other words, codewords are stored in
	 * right-to-left fashion.
	 *
	 * @return the codewords.
	 */

	BitVector[] codeWords();
}