/// <summary>
/// Parse TarHeader information from a header buffer.
/// </summary>
/// <param name = "header">
/// The tar entry header buffer to get information from.
/// </param>
public void ParseBuffer(byte[] header)
{
if (header == null)
{
throw new ArgumentNullException("header");
}
int offset = 0;
name = TarHeader.ParseName(header, offset, TarHeader.NAMELEN).ToString();
offset += TarHeader.NAMELEN;
mode = (int)TarHeader.ParseOctal(header, offset, TarHeader.MODELEN);
offset += TarHeader.MODELEN;
UserId = (int)TarHeader.ParseOctal(header, offset, TarHeader.UIDLEN);
offset += TarHeader.UIDLEN;
GroupId = (int)TarHeader.ParseOctal(header, offset, TarHeader.GIDLEN);
offset += TarHeader.GIDLEN;
Size = TarHeader.ParseOctal(header, offset, TarHeader.SIZELEN);
offset += TarHeader.SIZELEN;
ModTime = GetDateTimeFromCTime(TarHeader.ParseOctal(header, offset, TarHeader.MODTIMELEN));
offset += TarHeader.MODTIMELEN;
checksum = (int)TarHeader.ParseOctal(header, offset, TarHeader.CHKSUMLEN);
offset += TarHeader.CHKSUMLEN;
TypeFlag = header[offset++];
LinkName = TarHeader.ParseName(header, offset, TarHeader.NAMELEN).ToString();
offset += TarHeader.NAMELEN;
Magic = TarHeader.ParseName(header, offset, TarHeader.MAGICLEN).ToString();
offset += TarHeader.MAGICLEN;
Version = TarHeader.ParseName(header, offset, TarHeader.VERSIONLEN).ToString();
offset += TarHeader.VERSIONLEN;
UserName = TarHeader.ParseName(header, offset, TarHeader.UNAMELEN).ToString();
offset += TarHeader.UNAMELEN;
GroupName = TarHeader.ParseName(header, offset, TarHeader.GNAMELEN).ToString();
offset += TarHeader.GNAMELEN;
DevMajor = (int)TarHeader.ParseOctal(header, offset, TarHeader.DEVLEN);
offset += TarHeader.DEVLEN;
DevMinor = (int)TarHeader.ParseOctal(header, offset, TarHeader.DEVLEN);
// Fields past this point not currently parsed or used...
isChecksumValid = Checksum == TarHeader.MakeCheckSum(header);
}
/// <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 (this.hasHitEOF)
{
return(null);
}
if (this.currentEntry != null)
{
SkipToNextEntry();
}
byte[] headerBuf = this.buffer.ReadBlock();
if (headerBuf == null)
{
this.hasHitEOF = true;
}
else if (TarBuffer.IsEndOfArchiveBlock(headerBuf))
{
this.hasHitEOF = true;
}
if (this.hasHitEOF)
{
this.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.buffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_GHDR) // POSIX global extended header
// Ignore things we dont understand completely for now
{
SkipToNextEntry();
headerBuf = this.buffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_XHDR) // POSIX extended header
// Ignore things we dont understand completely for now
{
SkipToNextEntry();
headerBuf = this.buffer.ReadBlock();
}
else if (header.TypeFlag == TarHeader.LF_GNU_VOLHDR)
{
// TODO: could show volume name when verbose
SkipToNextEntry();
headerBuf = this.buffer.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 = this.buffer.ReadBlock();
}
if (this.entryFactory == null)
{
this.currentEntry = new TarEntry(headerBuf);
if (longName != null)
{
currentEntry.Name = longName.ToString();
}
}
else
{
this.currentEntry = this.entryFactory.CreateEntry(headerBuf);
}
// Magic was checked here for 'ustar' but there are multiple valid possibilities
// so this is not done anymore.
this.entryOffset = 0;
// TODO: Review How do we resolve this discrepancy?!
this.entrySize = this.currentEntry.Size;
} catch (InvalidHeaderException ex) {
this.entrySize = 0;
this.entryOffset = 0;
this.currentEntry = null;
string errorText = string.Format("Bad header in record {0} block {1} {2}",
buffer.CurrentRecord, buffer.CurrentBlock, ex.Message);
throw new InvalidHeaderException(errorText);
}
}
return(this.currentEntry);
}