internal static ZipEntry Create(String filename)
{
ZipEntry entry = new ZipEntry();
entry._FileName = filename;
entry._LastModified = System.IO.File.GetLastWriteTime(filename);
// adjust the time if the .NET BCL thinks it is in DST.
// see the note elsewhere in this file for more info.
if (entry._LastModified.IsDaylightSavingTime())
{
System.DateTime AdjustedTime = entry._LastModified - new System.TimeSpan(1, 0, 0);
entry._LastModDateTime = TomShane.Neoforce.External.Zip.Shared.DateTimeToPacked(AdjustedTime);
}
else
entry._LastModDateTime = TomShane.Neoforce.External.Zip.Shared.DateTimeToPacked(entry._LastModified);
// we don't actually slurp in the file until the caller invokes Write on this entry.
return entry;
}
private static bool ReadHeader(System.IO.Stream s, ZipEntry ze)
{
int signature = TomShane.Neoforce.External.Zip.Shared.ReadSignature(s);
// return null if this is not a local file header signature
if (SignatureIsNotValid(signature))
{
s.Seek(-4, System.IO.SeekOrigin.Current);
if (ze._Debug) System.Console.WriteLine(" ZipEntry::Read(): Bad signature ({0:X8}) at position {1}", signature, s.Position);
return false;
}
byte[] block = new byte[26];
int n = s.Read(block, 0, block.Length);
if (n != block.Length) return false;
int i = 0;
ze._VersionNeeded = (short)(block[i++] + block[i++] * 256);
ze._BitField = (short)(block[i++] + block[i++] * 256);
ze._CompressionMethod = (short)(block[i++] + block[i++] * 256);
ze._LastModDateTime = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
// the PKZIP spec says that if bit 3 is set (0x0008), then the CRC, Compressed size, and uncompressed size
// come directly after the file data. The only way to find it is to scan the zip archive for the signature of
// the Data Descriptor, and presume that that signature does not appear in the (compressed) data of the compressed file.
if ((ze._BitField & 0x0008) != 0x0008)
{
ze._Crc32 = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
ze._CompressedSize = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
ze._UncompressedSize = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
}
else
{
// the CRC, compressed size, and uncompressed size are stored later in the stream.
// here, we advance the pointer.
i += 12;
}
Int16 filenameLength = (short)(block[i++] + block[i++] * 256);
Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256);
block = new byte[filenameLength];
n = s.Read(block, 0, block.Length);
ze._FileName = TomShane.Neoforce.External.Zip.Shared.StringFromBuffer(block, 0, block.Length);
ze._Extra = new byte[extraFieldLength];
n = s.Read(ze._Extra, 0, ze._Extra.Length);
// transform the time data into something usable
ze._LastModified = TomShane.Neoforce.External.Zip.Shared.PackedToDateTime(ze._LastModDateTime);
// actually get the compressed size and CRC if necessary
if ((ze._BitField & 0x0008) == 0x0008)
{
long posn = s.Position;
long SizeOfDataRead = TomShane.Neoforce.External.Zip.Shared.FindSignature(s, ZipEntryDataDescriptorSignature);
if (SizeOfDataRead == -1) return false;
// read 3x 4-byte fields (CRC, Compressed Size, Uncompressed Size)
block = new byte[12];
n = s.Read(block, 0, block.Length);
if (n != 12) return false;
i = 0;
ze._Crc32 = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
ze._CompressedSize = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
ze._UncompressedSize = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
if (SizeOfDataRead != ze._CompressedSize)
throw new Exception("Data format error (bit 3 is set)");
// seek back to previous position, to read file data
s.Seek(posn, System.IO.SeekOrigin.Begin);
}
return true;
}
internal static ZipEntry Read(System.IO.Stream s, bool TurnOnDebug)
{
ZipEntry entry = new ZipEntry();
entry._Debug = TurnOnDebug;
if (!ReadHeader(s, entry)) return null;
entry.__filedata = new byte[entry.CompressedSize];
int n = s.Read(entry._FileData, 0, entry._FileData.Length);
if (n != entry._FileData.Length)
{
throw new Exception("badly formatted zip file.");
}
// finally, seek past the (already read) Data descriptor if necessary
if ((entry._BitField & 0x0008) == 0x0008)
{
s.Seek(16, System.IO.SeekOrigin.Current);
}
return entry;
}
internal ZipDirEntry(ZipEntry ze) { }
