Package 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 Object implements TarConstants
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.

  • Constructor Details

    • TarArchiveSparseEntry

      public TarArchiveSparseEntry(byte[] headerBuf) throws IOException
      Constructs an entry from an archive's header bytes. File is set to null.
      Parameters:
      headerBuf - The header bytes from a tar archive entry.
      Throws:
      IOException - on unknown format

  • Method Details