/// <summary>
/// Releases unmanaged and - optionally - managed resources.
/// </summary>
/// <param name="disposing">
/// <c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only
/// unmanaged resources.
/// </param>
private void Dispose(bool disposing)
{
_disposed = true;
if (disposing)
{
_activeEntryStream?.Dispose();
_activeEntryStream = null;
_stream = null;
}
}
/// <summary>
/// Returns the next entry in the archive.
/// </summary>
/// <returns>The next entry in the archive or null when there are no more remaining entries.</returns>
public TarEntryStream Next()
{
AssertNotDisposed();
if (_finished)
{
return(null);
}
CloseActiveEntryStream();
var header = TarHeader.Deserialize(_stream);
if (header == null)
{
_finished = true;
return(null);
}
// Compile a header with all additional annotations found.
var headerBag = new TarHeaderBag();
var annotationStream = new TarEntryStream(new ReadOnlyTarHeader(header), _stream);
// Keep adding the stream to the header bag while they are annotations.
while (headerBag.Add(annotationStream))
{
// Re-align the input stream to the 512 blocks and close the annotation stream.
MoveToEndOfStream(annotationStream);
annotationStream.Dispose();
header = TarHeader.Deserialize(_stream);
// The annotation appears to be the last entry in the archive. Throwing an exception seems little crude
// since the rest of the archive was just fine.
if (header == null)
{
_finished = true;
return(null);
}
// Create a new annotation stream for the next round of checks.
annotationStream = new TarEntryStream(new ReadOnlyTarHeader(header), _stream);
}
// The annotation is not used at this point - skip it.
annotationStream.Dispose();
_activeEntryStream = new TarEntryStream(headerBag.ApplyTo(header), _stream);
return(_activeEntryStream);
}
/// <summary>
/// Moves the <see cref="_stream" /> to the end of the specified <paramref name="entryStream" />.
/// </summary>
/// <param name="entryStream">The entry stream.</param>
private void MoveToEndOfStream(TarEntryStream entryStream)
{
// If previous stream isset, move past it's contents.
if (entryStream == null)
{
return;
}
var length = entryStream.Header.Size ?? 0;
var padding = TarBlock.RemainingBlockSize(length);
var remaining = length - entryStream.PositionInternal + padding;
// Skip remainder and re-align to 512 blocks
for (; remaining > 0; remaining--)
{
_stream.ReadByte();
}
}
/// <summary>
/// Closes the active entry stream and moves <see cref="_stream" /> to the end of the entry.
/// </summary>
private void CloseActiveEntryStream()
{
MoveToEndOfStream(_activeEntryStream);
_activeEntryStream?.Dispose();
_activeEntryStream = null;
}