001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.commons.compress.archivers.tar; 020 021import java.io.IOException; 022 023/** 024 * This class represents a sparse entry in a Tar archive. 025 * 026 * <p> 027 * The C structure for a sparse entry is: 028 * <pre> 029 * struct posix_header { 030 * struct sparse sp[21]; // TarConstants.SPARSELEN_GNU_SPARSE - offset 0 031 * char isextended; // TarConstants.ISEXTENDEDLEN_GNU_SPARSE - offset 504 032 * }; 033 * </pre> 034 * Whereas, "struct sparse" is: 035 * <pre> 036 * struct sparse { 037 * char offset[12]; // offset 0 038 * char numbytes[12]; // offset 12 039 * }; 040 * </pre> 041 */ 042 043public class TarArchiveSparseEntry implements TarConstants { 044 /** If an extension sparse header follows. */ 045 private final boolean isExtended; 046 047 /** 048 * Construct an entry from an archive's header bytes. File is set 049 * to null. 050 * 051 * @param headerBuf The header bytes from a tar archive entry. 052 * @throws IOException on unknown format 053 */ 054 public TarArchiveSparseEntry(final byte[] headerBuf) throws IOException { 055 int offset = 0; 056 offset += SPARSELEN_GNU_SPARSE; 057 isExtended = TarUtils.parseBoolean(headerBuf, offset); 058 } 059 060 public boolean isExtended() { 061 return isExtended; 062 } 063}