public async Task CreateEntryAsync(TarEntry entry)
{
ValidateWroteAll();
var paxAttributes = new Dictionary <string, string>();
// Clear padding.
for (int i = 0; i < TarCommon.BlockSize; i++)
{
_buffer[i] = 0;
}
var state = new TarHeaderView(_buffer, TarCommon.BlockSize, paxAttributes);
var padding = _remainingPadding;
_remainingPadding = 0;
GenerateHeader(ref state, entry, default(ArraySegment <byte>));
if (paxAttributes.Count > 0)
{
padding = await WritePaxEntry(entry, paxAttributes, padding);
}
await _stream.WriteAsync(_buffer, TarCommon.BlockSize - padding, TarCommon.BlockSize + padding);
_remaining = entry.Length;
_remainingPadding = TarCommon.Padding(_remaining);
}
private async Task <int> WritePaxEntry(TarEntry entry, Dictionary <string, string> paxAttributes, int padding)
{
var paxStream = new MemoryStream();
// Skip the tar header, then go back and write it later.
var paxDataOffset = padding + TarCommon.BlockSize;
paxStream.SetLength(paxDataOffset);
paxStream.Position = paxDataOffset;
foreach (var attribute in paxAttributes)
{
WritePaxAttribute(paxStream, attribute.Key, attribute.Value);
}
var paxEntry = new TarEntry
{
Type = TarCommon.PaxHeaderType,
Length = paxStream.Length - paxDataOffset,
};
ArraySegment <byte> buffer;
paxStream.TryGetBuffer(out buffer);
var paxHeader = new TarHeaderView(buffer.Array, buffer.Offset + padding, null);
GenerateHeader(ref paxHeader, paxEntry, GetPaxName(entry.Name));
paxStream.Position = 0;
await paxStream.CopyToAsync(_stream);
return(TarCommon.Padding(paxEntry.Length));
}
private async Task <TarEntry> ReadHeader(Dictionary <string, string> paxAttributes)
{
if (_remaining > 0)
{
await Skip(_remaining);
_remaining = 0;
}
var read = await _stream.ReadAsync(_buffer, 0, TarCommon.BlockSize + _remainingPadding);
var padding = _remainingPadding;
_remainingPadding = 0;
if (read <= _remainingPadding)
{
// No more entries.
return(null);
}
else if (read - _remainingPadding < TarCommon.BlockSize)
{
throw new EndOfStreamException();
}
if (IsArrayZero(padding, TarCommon.BlockSize))
{
// Verify that the next block is also zero.
read = await _stream.ReadAsync(_buffer, 0, TarCommon.BlockSize);
if (read == 0)
{
return(null);
}
else if (read < TarCommon.BlockSize)
{
throw new EndOfStreamException();
}
else if (IsArrayZero(0, TarCommon.BlockSize))
{
return(null);
}
else
{
throw new TarParseException("non-zero header after zero header");
}
}
var header = new TarHeaderView(_buffer, padding, paxAttributes);
var entry = ParseHeader(ref header);
_remaining = entry.Length;
_remainingPadding = TarCommon.Padding(_remaining);
return(entry);
}
