solr/core/src/java/org/apache/solr/util/hll/IWordDeserializer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.solr.util.hll;

/**
 * Reads 'words' of a fixed width, in sequence, from a byte array.
 */
public interface IWordDeserializer {
    /**
     * @return the next word in the sequence. Should not be called more than
     * {@link #totalWordCount()} times.
     */
    long readWord();

    /**
     * Returns the number of words that could be encoded in the sequence.
     *
     * NOTE:  the sequence that was encoded may be shorter than the value this
     *        method returns due to padding issues within bytes. This guarantees
     *        only an upper bound on the number of times {@link #readWord()}
     *        can be called.
     *
     * @return the maximum number of words that could be read from the sequence.
     */
    int totalWordCount();
}