org.apache.commons.compress.archivers.tar

Class TarArchiveSparseEntry

java.lang.Object

org.apache.commons.compress.archivers.tar.TarArchiveSparseEntry

All Implemented Interfaces:

TarConstants

public class TarArchiveSparseEntry
extends java.lang.Object
implements TarConstants

This class represents a sparse entry in a Tar archive.

The C structure for a sparse entry is:

 struct posix_header {
 struct sparse sp[21]; // TarConstants.SPARSELEN_GNU_SPARSE     - offset 0
 char isextended;      // TarConstants.ISEXTENDEDLEN_GNU_SPARSE - offset 504
 };
 

Whereas, "struct sparse" is:

 struct sparse {
 char offset[12];   // offset 0
 char numbytes[12]; // offset 12
 };
 

Each such struct describes a block of data that has actually been written to the archive. The offset describes where in the extracted file the data is supposed to start and the numbytes provides the length of the block. When extracting the entry the gaps between the sparse structs are equivalent to areas filled with zero bytes.

Field Summary

Fields inherited from interface org.apache.commons.compress.archivers.tar.TarConstants

ATIMELEN_GNU, ATIMELEN_XSTAR, CHKSUM_OFFSET, CHKSUMLEN, CTIMELEN_GNU, CTIMELEN_XSTAR, DEFAULT_BLKSIZE, DEFAULT_RCDSIZE, DEVLEN, FORMAT_OLDGNU, FORMAT_POSIX, FORMAT_XSTAR, GIDLEN, GNAMELEN, GNU_LONGLINK, ISEXTENDEDLEN_GNU, ISEXTENDEDLEN_GNU_SPARSE, LF_BLK, LF_CHR, LF_CONTIG, LF_DIR, LF_FIFO, LF_GNUTYPE_LONGLINK, LF_GNUTYPE_LONGNAME, LF_GNUTYPE_SPARSE, LF_LINK, LF_MULTIVOLUME, LF_NORMAL, LF_OFFSET, LF_OLDNORM, LF_PAX_EXTENDED_HEADER_LC, LF_PAX_EXTENDED_HEADER_UC, LF_PAX_GLOBAL_EXTENDED_HEADER, LF_SYMLINK, LONGNAMESLEN_GNU, MAGIC_ANT, MAGIC_GNU, MAGIC_OFFSET, MAGIC_POSIX, MAGIC_XSTAR, MAGICLEN, MAXID, MAXSIZE, MODELEN, MODTIMELEN, NAMELEN, OFFSETLEN_GNU, PAD2LEN_GNU, PREFIXLEN, PREFIXLEN_XSTAR, REALSIZELEN_GNU, SIZELEN, SPARSE_HEADERS_IN_EXTENSION_HEADER, SPARSE_HEADERS_IN_OLDGNU_HEADER, SPARSE_NUMBYTES_LEN, SPARSE_OFFSET_LEN, SPARSELEN_GNU, SPARSELEN_GNU_SPARSE, UIDLEN, UNAMELEN, VERSION_ANT, VERSION_GNU_SPACE, VERSION_GNU_ZERO, VERSION_OFFSET, VERSION_POSIX, VERSIONLEN, XSTAR_ATIME_OFFSET, XSTAR_CTIME_OFFSET, XSTAR_MAGIC_LEN, XSTAR_MAGIC_OFFSET, XSTAR_MULTIVOLUME_OFFSET, XSTAR_PREFIX_OFFSET

Constructor Summary

Constructors

Constructor and Description
TarArchiveSparseEntry(byte[] headerBuf) Construct an entry from an archive's header bytes.

Method Summary

Modifier and Type	Method and Description
java.util.List<TarArchiveStructSparse>	getSparseHeaders() Obtains information about the configuration for the sparse entry.
boolean	isExtended()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TarArchiveSparseEntry

public TarArchiveSparseEntry(byte[] headerBuf)
                      throws java.io.IOException

Construct an entry from an archive's header bytes. File is set to null.

Parameters:

headerBuf - The header bytes from a tar archive entry.

Throws:

java.io.IOException - on unknown format

Method Detail

isExtended

public boolean isExtended()

getSparseHeaders

public java.util.List<TarArchiveStructSparse> getSparseHeaders()

Obtains information about the configuration for the sparse entry.

Returns:

information about the configuration for the sparse entry.

Since:

1.20