/// <summary>
/// Get the next entry in this tar archive. This will skip
/// over any remaining data in the current entry, if there
/// is one, and place the input stream at the header of the
/// next entry, and read the header and instantiate a new
/// TarEntry from the header bytes and return that entry.
/// If there are no more entries in the archive, null will
/// be returned to indicate that the end of the archive has
/// been reached.
/// </summary>
/// <returns>
/// The next TarEntry in the archive, or null.
/// </returns>
public TarEntry GetNextEntry()
{
if (hasHitEOF) {
return null;
}
if (currentEntry != null) {
SkipToNextEntry();
}
byte[] headerBuf = tarBuffer.ReadBlock();
if (headerBuf == null) {
hasHitEOF = true;
} else if (TarBuffer.IsEndOfArchiveBlock(headerBuf)) {
hasHitEOF = true;
}
if (hasHitEOF) {
currentEntry = null;
} else {
try {
TarHeader header = new TarHeader();
header.ParseBuffer(headerBuf);
if ( !header.IsChecksumValid )
{
throw new TarException("Header checksum is invalid");
}
this.entryOffset = 0;
this.entrySize = header.Size;
StringBuilder longName = null;
if (header.TypeFlag == TarHeader.LF_GNU_LONGNAME) {
byte[] nameBuffer = new byte[TarBuffer.BlockSize];
long numToRead = this.entrySize;
longName = new StringBuilder();
while (numToRead > 0) {
int numRead = this.Read(nameBuffer, 0, (numToRead > nameBuffer.Length ? nameBuffer.Length : (int)numToRead));
if (numRead == -1) {
throw new InvalidHeaderException("Failed to read long name entry");
}
longName.Append(TarHeader.ParseName(nameBuffer, 0, numRead).ToString());
numToRead -= numRead;
}
SkipToNextEntry();
headerBuf = this.tarBuffer.ReadBlock();
} else if (header.TypeFlag == TarHeader.LF_GHDR) { // POSIX global extended header
// Ignore things we dont understand completely for now
SkipToNextEntry();
headerBuf = this.tarBuffer.ReadBlock();
} else if (header.TypeFlag == TarHeader.LF_XHDR) { // POSIX extended header
// Ignore things we dont understand completely for now
SkipToNextEntry();
headerBuf = this.tarBuffer.ReadBlock();
} else if (header.TypeFlag == TarHeader.LF_GNU_VOLHDR) {
// TODO: could show volume name when verbose
SkipToNextEntry();
headerBuf = this.tarBuffer.ReadBlock();
} else if (header.TypeFlag != TarHeader.LF_NORMAL &&
header.TypeFlag != TarHeader.LF_OLDNORM &&
header.TypeFlag != TarHeader.LF_DIR) {
// Ignore things we dont understand completely for now
SkipToNextEntry();
headerBuf = tarBuffer.ReadBlock();
}
if (entryFactory == null) {
currentEntry = new TarEntry(headerBuf);
if (longName != null) {
currentEntry.Name = longName.ToString();
}
} else {
currentEntry = entryFactory.CreateEntry(headerBuf);
}
// Magic was checked here for 'ustar' but there are multiple valid possibilities
// so this is not done anymore.
entryOffset = 0;
// TODO: Review How do we resolve this discrepancy?!
entrySize = this.currentEntry.Size;
} catch (InvalidHeaderException ex) {
entrySize = 0;
entryOffset = 0;
currentEntry = null;
string errorText = string.Format("Bad header in record {0} block {1} {2}",
tarBuffer.CurrentRecord, tarBuffer.CurrentBlock, ex.Message);
throw new InvalidHeaderException(errorText);
}
}
return currentEntry;
}
/// <summary>
/// Construct an entry from an archive's header bytes. File is set
/// to null.
/// </summary>
/// <param name = "headerBuffer">
/// The header bytes from a tar archive entry.
/// </param>
public TarEntry(byte[] headerBuffer)
{
header = new TarHeader();
header.ParseBuffer(headerBuffer);
}