/// <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();
}
var headerBuf = tarBuffer.ReadBlock();
if (headerBuf == null)
{
hasHitEOF = true;
}
else if (TarBuffer.IsEndOfArchiveBlock(headerBuf))
{
hasHitEOF = true;
}
if (hasHitEOF)
{
currentEntry = null;
}
else
{
try {
var header = new TarHeader();
header.ParseBuffer(headerBuf);
if (!header.IsChecksumValid)
{
throw new TarException("Header checksum is invalid");
}
entryOffset = 0;
entrySize = header.Size;
StringBuilder longName = null;
if (header.TypeFlag == TarHeader.LF_GNU_LONGNAME)
{
var nameBuffer = new byte[TarBuffer.BlockSize];
var numToRead = entrySize;
longName = new StringBuilder();
while (numToRead > 0)
{
var numRead = 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));
numToRead -= numRead;
}
SkipToNextEntry();
headerBuf = tarBuffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_GHDR) // POSIX global extended header
// Ignore things we dont understand completely for now
{
SkipToNextEntry();
headerBuf = tarBuffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_XHDR) // POSIX extended header
// Ignore things we dont understand completely for now
{
SkipToNextEntry();
headerBuf = tarBuffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_GNU_VOLHDR)
{
// TODO: could show volume name when verbose
SkipToNextEntry();
headerBuf = 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 = currentEntry.Size;
} catch (InvalidHeaderException ex) {
entrySize = 0;
entryOffset = 0;
currentEntry = null;
var 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 TarBuffer for writing Tar output to streams.
/// </summary>
/// <param name="outputStream">Output stream to write to.</param>
/// <param name="blockFactor">Blocking factor to apply</param>
/// <returns>A new <see cref="TarBuffer"/> suitable for output.</returns>
public static TarBuffer CreateOutputTarBuffer(Stream outputStream, int blockFactor)
{
if ( outputStream == null )
{
throw new ArgumentNullException("outputStream");
}
if ( blockFactor <= 0 )
{
#if NETCF_1_0
throw new ArgumentOutOfRangeException("blockFactor");
#else
throw new ArgumentOutOfRangeException("blockFactor", "Factor cannot be negative");
#endif
}
var tarBuffer = new TarBuffer();
tarBuffer.inputStream = null;
tarBuffer.outputStream = outputStream;
tarBuffer.Initialize(blockFactor);
return tarBuffer;
}
/// <summary>
/// Construct a TarInputStream with user specified block factor
/// </summary>
/// <param name="inputStream">stream to source data from</param>
/// <param name="blockFactor">block factor to apply to archive</param>
public TarInputStream(Stream inputStream, int blockFactor)
{
this.inputStream = inputStream;
tarBuffer = TarBuffer.CreateInputTarBuffer(inputStream, blockFactor);
}