internal static void HandlePK00Prefix(Stream s)
{
// in some cases, the zip file begins with "PK00". This is a throwback and is rare,
// but we handle it anyway. We do not change behavior based on it.
uint datum = (uint)SharedUtilities.ReadInt(s);
if (datum != ZipConstants.PackedToRemovableMedia)
{
s.Seek(-4, SeekOrigin.Current); // unread the block
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
}
}
private static void HandleUnexpectedDataDescriptor(ZipEntry entry)
{
Stream s = entry.ArchiveStream;
// In some cases, the "data descriptor" is present, without a signature, even when
// bit 3 of the BitField is NOT SET. This is the CRC, followed
// by the compressed length and the uncompressed length (4 bytes for each
// of those three elements). Need to check that here.
//
uint datum = (uint)SharedUtilities.ReadInt(s);
if (datum == entry._Crc32)
{
int sz = SharedUtilities.ReadInt(s);
if (sz == entry._CompressedSize)
{
sz = SharedUtilities.ReadInt(s);
if (sz == entry._UncompressedSize)
{
// ignore everything and discard it.
}
else
{
s.Seek(-12, SeekOrigin.Current); // unread the three blocks
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
}
}
else
{
s.Seek(-8, SeekOrigin.Current); // unread the two blocks
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
}
}
else
{
s.Seek(-4, SeekOrigin.Current); // unread the block
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
}
}
private static void Zip64SeekToCentralDirectory(ZipFile zf)
{
Stream s = zf.ReadStream;
byte[] block = new byte[16];
// seek back to find the ZIP64 EoCD.
// I think this might not work for .NET CF ?
s.Seek(-40, SeekOrigin.Current);
s.Read(block, 0, 16);
Int64 offset64 = BitConverter.ToInt64(block, 8);
zf._OffsetOfCentralDirectory = 0xFFFFFFFF;
zf._OffsetOfCentralDirectory64 = offset64;
// change for workitem 8098
s.Seek(offset64, SeekOrigin.Begin);
//zf.SeekFromOrigin(Offset64);
uint datum = (uint)SharedUtilities.ReadInt(s);
if (datum != ZipConstants.Zip64EndOfCentralDirectoryRecordSignature)
{
throw new BadReadException(String.Format(" Bad signature (0x{0:X8}) looking for ZIP64 EoCD Record at position 0x{1:X8}", datum, s.Position));
}
s.Read(block, 0, 8);
Int64 Size = BitConverter.ToInt64(block, 0);
block = new byte[Size];
s.Read(block, 0, block.Length);
offset64 = BitConverter.ToInt64(block, 36);
// change for workitem 8098
s.Seek(offset64, SeekOrigin.Begin);
//zf.SeekFromOrigin(Offset64);
}
private static uint ReadFirstFourBytes(Stream s)
{
uint datum = (uint)SharedUtilities.ReadInt(s);
return(datum);
}