/// <summary>
/// Write an archive record to the archive, where the record may be
/// inside of a larger array buffer. The buffer must be "offset plus
/// record size" long.
/// </summary>
/// <param name="buffer">
/// The buffer containing the record data to write.
/// </param>
/// <param name="offset">
/// The offset of the record data within buffer.
/// </param>
public void WriteBlock(byte[] buffer, int offset)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (outputStream == null)
{
throw TarException.UnKnown("TarBuffer.WriteBlock - no output stream stream defined");
}
if ((offset < 0) || (offset >= buffer.Length))
{
throw new ArgumentOutOfRangeException(nameof(offset));
}
if ((offset + BlockSize) > buffer.Length)
{
string errorText = string.Format("TarBuffer.WriteBlock - record has length '{0}' with offset '{1}' which is less than the record size of '{2}'",
buffer.Length, offset, recordSize);
throw TarException.UnKnown(errorText);
}
if (currentBlockIndex >= BlockFactor)
{
WriteRecord();
}
Array.Copy(buffer, offset, recordBuffer, (currentBlockIndex * BlockSize), BlockSize);
currentBlockIndex++;
}
/// <summary>
/// Write a block of data to the archive.
/// </summary>
/// <param name="block">
/// The data to write to the archive.
/// </param>
public void WriteBlock(byte[] block)
{
if (block == null)
{
throw new ArgumentNullException(nameof(block));
}
if (outputStream == null)
{
throw TarException.UnKnown("TarBuffer.WriteBlock - no output stream defined");
}
if (block.Length != BlockSize)
{
string errorText = string.Format("TarBuffer.WriteBlock - block to write has length '{0}' which is not the block size of '{1}'",
block.Length, BlockSize);
throw TarException.UnKnown(errorText);
}
if (currentBlockIndex >= BlockFactor)
{
WriteRecord();
}
Array.Copy(block, 0, recordBuffer, (currentBlockIndex * BlockSize), BlockSize);
currentBlockIndex++;
}
/// <summary>
/// Write a TarBuffer record to the archive.
/// </summary>
void WriteRecord()
{
if (outputStream == null)
{
throw TarException.UnKnown("TarBuffer.WriteRecord no output stream defined");
}
outputStream.Write(recordBuffer, 0, RecordSize);
outputStream.Flush();
currentBlockIndex = 0;
currentRecordIndex++;
}
/// <summary>
/// WriteFinalRecord writes the current record buffer to output any unwritten data is present.
/// </summary>
/// <remarks>Any trailing bytes are set to zero which is by definition correct behaviour
/// for the end of a tar stream.</remarks>
void WriteFinalRecord()
{
if (outputStream == null)
{
throw TarException.UnKnown("TarBuffer.WriteFinalRecord no output stream defined");
}
if (currentBlockIndex > 0)
{
int dataBytes = currentBlockIndex * BlockSize;
Array.Clear(recordBuffer, dataBytes, RecordSize - dataBytes);
WriteRecord();
}
outputStream.Flush();
}
/// <summary>
/// Skip over a block on the input stream.
/// </summary>
public void SkipBlock()
{
if (inputStream == null)
{
throw TarException.UnKnown("no input stream defined");
}
if (currentBlockIndex >= BlockFactor)
{
if (!ReadRecord())
{
throw TarException.UnKnown("Failed to read a record");
}
}
currentBlockIndex++;
}
/// <summary>
/// Read a record from data stream.
/// </summary>
/// <returns>
/// false if End-Of-File, else true.
/// </returns>
bool ReadRecord()
{
if (inputStream == null)
{
throw TarException.UnKnown("no input stream stream defined");
}
currentBlockIndex = 0;
int offset = 0;
int bytesNeeded = RecordSize;
while (bytesNeeded > 0)
{
long numBytes = inputStream.Read(recordBuffer, offset, bytesNeeded);
//
// NOTE
// We have found EOF, and the record is not full!
//
// This is a broken archive. It does not follow the standard
// blocking algorithm. However, because we are generous, and
// it requires little effort, we will simply ignore the error
// and continue as if the entire record were read. This does
// not appear to break anything upstream. We used to return
// false in this case.
//
// Thanks to '*****@*****.**' for this fix.
//
if (numBytes <= 0)
{
break;
}
offset += (int)numBytes;
bytesNeeded -= (int)numBytes;
}
currentRecordIndex++;
return(true);
}
/// <summary>
/// Read a block from the input stream.
/// </summary>
/// <returns>
/// The block of data read.
/// </returns>
public byte[] ReadBlock()
{
if (inputStream == null)
{
throw TarException.UnKnown("TarBuffer.ReadBlock - no input stream defined");
}
if (currentBlockIndex >= BlockFactor)
{
if (!ReadRecord())
{
throw TarException.UnKnown("Failed to read a record");
}
}
byte[] result = new byte[BlockSize];
Array.Copy(recordBuffer, (currentBlockIndex * BlockSize), result, 0, BlockSize);
currentBlockIndex++;
return(result);
}
/// <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
{
hasHitEOF |= TarBuffer.IsEndOfArchiveBlock(headerBuf);
}
if (hasHitEOF)
{
currentEntry = null;
}
else
{
try
{
var header = new TarHeader();
header.ParseBuffer(headerBuf);
if (!header.IsChecksumValid)
{
throw TarException.InvalidHeader("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 TarException.UnKnown("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_LINK &&
header.TypeFlag != TarHeader.LF_SYMLINK &&
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 (TarException 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 TarException.UnKnown(errorText);
}
}
return(currentEntry);
}