001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.io;
019
020import java.io.IOException;
021import java.io.RandomAccessFile;
022
023/**
024 * Works on RandomAccessFile.
025 *
026 * @since 2.13.0
027 */
028public class RandomAccessFiles {
029
030    /**
031     * Reads a byte array starting at "position" for "length" bytes.
032     *
033     * @param input    The source RandomAccessFile.
034     * @param position The offset position, measured in bytes from the beginning of the file, at which to set the file pointer.
035     * @param length   How many bytes to read.
036     * @return a new byte array.
037     * @throws IOException If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some
038     *                     other I/O error occurs.
039     */
040    public static byte[] read(final RandomAccessFile input, final long position, final int length) throws IOException {
041        input.seek(position);
042        return IOUtils.toByteArray(input::read, length);
043    }
044
045}