/// <summary>
/// Read the data from the stream into the buffer.
/// </summary>
///
/// <remarks>
/// <para>
/// The data for the zipentry will be decrypted and uncompressed, as
/// necessary, before being copied into the buffer.
/// </para>
///
/// <para>
/// You must set the <see cref="Password"/> property before calling
/// <c>Read()</c> the first time for an encrypted entry. To determine if an
/// entry is encrypted and requires a password, check the <see
/// cref="ZipEntry.Encryption">ZipEntry.Encryption</see> property.
/// </para>
/// </remarks>
///
/// <param name="buffer">The buffer to hold the data read from the stream.</param>
/// <param name="offset">the offset within the buffer to copy the first byte read.</param>
/// <param name="count">the number of bytes to read.</param>
/// <returns>the number of bytes read, after decryption and decompression.</returns>
public override int Read(byte[] buffer, int offset, int count)
{
if (_closed)
{
_exceptionPending = true;
throw new System.InvalidOperationException("The stream has been closed.");
}
if (_needSetup)
{
SetupStream();
}
if (_LeftToRead == 0)
{
return(0);
}
int len = (_LeftToRead > count) ? count : (int)_LeftToRead;
int n = _crcStream.Read(buffer, offset, len);
_LeftToRead -= n;
if (_LeftToRead == 0)
{
int CrcResult = _crcStream.Crc;
_currentEntry.VerifyCrcAfterExtract(CrcResult);
_inputStream.Seek(_endOfEntry, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_inputStream);
}
return(n);
}
/// <summary>
/// Read the next entry from the zip file.
/// </summary>
///
/// <remarks>
/// <para>
/// Call this method just before calling <see cref="Read(byte[], int, int)"/>,
/// to position the pointer in the zip file to the next entry that can be
/// read. Subsequent calls to <c>Read()</c>, will decrypt and decompress the
/// data in the zip file, until <c>Read()</c> returns 0.
/// </para>
///
/// <para>
/// Each time you call <c>GetNextEntry()</c>, the pointer in the wrapped
/// stream is moved to the next entry in the zip file. If you call <see
/// cref="Seek(long, SeekOrigin)"/>, and thus re-position the pointer within
/// the file, you will need to call <c>GetNextEntry()</c> again, to insure
/// that the file pointer is positioned at the beginning of a zip entry.
/// </para>
///
/// <para>
/// This method returns the <c>ZipEntry</c>. Using a stream approach, you will
/// read the raw bytes for an entry in a zip file via calls to <c>Read()</c>.
/// Alternatively, you can extract an entry into a file, or a stream, by
/// calling <see cref="ZipEntry.Extract()"/>, or one of its siblings.
/// </para>
///
/// </remarks>
///
/// <returns>
/// The <c>ZipEntry</c> read. Returns null (or Nothing in VB) if there are no more
/// entries in the zip file.
/// </returns>
///
public ZipEntry GetNextEntry()
{
if (_findRequired)
{
// find the next signature
long d = SharedUtilities.FindSignature(_inputStream, ZipConstants.ZipEntrySignature);
if (d == -1)
{
return(null);
}
// back up 4 bytes: ReadEntry assumes the file pointer is positioned before the entry signature
_inputStream.Seek(-4, SeekOrigin.Current);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_inputStream);
}
// workitem 10923
else if (_firstEntry)
{
// we've already read one entry.
// Seek to the end of it.
_inputStream.Seek(_endOfEntry, SeekOrigin.Begin);
SharedUtilities.Workaround_Ladybug318918(_inputStream);
}
_currentEntry = ZipEntry.ReadEntry(_container, !_firstEntry);
// ReadEntry leaves the file position after all the entry
// data and the optional bit-3 data descriptpr. This is
// where the next entry would normally start.
_endOfEntry = _inputStream.Position;
_firstEntry = true;
_needSetup = true;
_findRequired = false;
return(_currentEntry);
}
private void ReadExtraField()
{
_readExtraDepth++;
// workitem 8098: ok (restore)
long posn = this.ArchiveStream.Position;
this.ArchiveStream.Seek(this._RelativeOffsetOfLocalHeader, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream);
byte[] block = new byte[30];
this.ArchiveStream.Read(block, 0, block.Length);
int i = 26;
Int16 filenameLength = (short)(block[i++] + block[i++] * 256);
Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256);
// workitem 8098: ok (relative)
this.ArchiveStream.Seek(filenameLength, SeekOrigin.Current);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream);
ProcessExtraField(this.ArchiveStream, extraFieldLength);
// workitem 8098: ok (restore)
this.ArchiveStream.Seek(posn, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(this.ArchiveStream);
_readExtraDepth--;
}
public override long Seek(long offset, System.IO.SeekOrigin origin)
{
var x = _innerStream.Seek(offset, origin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_innerStream);
return(x);
}
/// <summary>
/// This method seeks in the underlying stream.
/// </summary>
///
/// <remarks>
/// <para>
/// Call this method if you want to seek around within the zip file for random access.
/// </para>
///
/// <para>
/// Applications can intermix calls to <c>Seek()</c> with calls to <see
/// cref="GetNextEntry()"/>. After a call to <c>Seek()</c>,
/// <c>GetNextEntry()</c> will get the next <c>ZipEntry</c> that falls after
/// the current position in the input stream. You're on your own for finding
/// out just where to seek in the stream, to get to the various entries.
/// </para>
///
/// </remarks>
///
/// <param name="offset">the offset point to seek to</param>
/// <param name="origin">the reference point from which to seek</param>
/// <returns>The new position</returns>
public override long Seek(long offset, SeekOrigin origin)
{
_findRequired = true;
var x = _inputStream.Seek(offset, origin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_inputStream);
return(x);
}
/// <summary>
/// Reads one <c>ZipEntry</c> from the given stream. The content for
/// the entry does not get decompressed or decrypted. This method
/// basically reads metadata, and seeks.
/// </summary>
/// <param name="zc">the ZipContainer this entry belongs to.</param>
/// <param name="first">
/// true of this is the first entry being read from the stream.
/// </param>
/// <returns>the <c>ZipEntry</c> read from the stream.</returns>
internal static ZipEntry ReadEntry(ZipContainer zc, bool first)
{
ZipFile zf = zc.ZipFile;
Stream s = zc.ReadStream;
System.Text.Encoding defaultEncoding = zc.AlternateEncoding;
ZipEntry entry = new ZipEntry();
entry._Source = ZipEntrySource.ZipFile;
entry._container = zc;
entry._archiveStream = s;
if (zf != null)
{
zf.OnReadEntry(true, null);
}
if (first)
{
HandlePK00Prefix(s);
}
// Read entry header, including any encryption header
if (!ReadHeader(entry, defaultEncoding))
{
return(null);
}
// Store the position in the stream for this entry
// change for workitem 8098
entry.__FileDataPosition = entry.ArchiveStream.Position;
// seek past the data without reading it. We will read on Extract()
s.Seek(entry._CompressedFileDataSize + entry._LengthOfTrailer, SeekOrigin.Current);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
// ReadHeader moves the file pointer to the end of the entry header,
// as well as any encryption header.
// CompressedFileDataSize includes:
// the maybe compressed, maybe encrypted file data
// the encryption trailer, if any
// the bit 3 descriptor, if any
// workitem 5306
// http://www.codeplex.com/DotNetZip/WorkItem/View.aspx?WorkItemId=5306
HandleUnexpectedDataDescriptor(entry);
if (zf != null)
{
zf.OnReadBytes(entry);
zf.OnReadEntry(false, entry);
}
return(entry);
}
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);
}
}
/// <summary>
/// Reads one entry from the zip directory structure in the zip file.
/// </summary>
///
/// <param name="zf">
/// The zipfile for which a directory entry will be read. From this param, the
/// method gets the ReadStream and the expected text encoding
/// (ProvisionalAlternateEncoding) which is used if the entry is not marked
/// UTF-8.
/// </param>
///
/// <param name="previouslySeen">
/// a list of previously seen entry names; used to prevent duplicates.
/// </param>
///
/// <returns>the entry read from the archive.</returns>
internal static ZipEntry ReadDirEntry(ZipFile zf,
Dictionary <String, Object> previouslySeen)
{
System.IO.Stream s = zf.ReadStream;
System.Text.Encoding expectedEncoding = (zf.AlternateEncodingUsage == ZipOption.Always)
? zf.AlternateEncoding
: ZipFile.DefaultEncoding;
int signature = SharedUtilities.ReadSignature(s);
// return null if this is not a local file header signature
if (IsNotValidZipDirEntrySig(signature))
{
s.Seek(-4, System.IO.SeekOrigin.Current);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(s);
// Getting "not a ZipDirEntry signature" here is not always wrong or an
// error. This can happen when walking through a zipfile. After the
// last ZipDirEntry, we expect to read an
// EndOfCentralDirectorySignature. When we get this is how we know
// we've reached the end of the central directory.
if (signature != ZipConstants.EndOfCentralDirectorySignature &&
signature != ZipConstants.Zip64EndOfCentralDirectoryRecordSignature &&
signature != ZipConstants.ZipEntrySignature // workitem 8299
)
{
throw new BadReadException(String.Format(" Bad signature (0x{0:X8}) at position 0x{1:X8}", signature, s.Position));
}
return(null);
}
int bytesRead = 42 + 4;
byte[] block = new byte[42];
int n = s.Read(block, 0, block.Length);
if (n != block.Length)
{
return(null);
}
int i = 0;
ZipEntry zde = new ZipEntry();
zde.AlternateEncoding = expectedEncoding;
zde._Source = ZipEntrySource.ZipFile;
zde._container = new ZipContainer(zf);
unchecked
{
zde._VersionMadeBy = (short)(block[i++] + block[i++] * 256);
zde._VersionNeeded = (short)(block[i++] + block[i++] * 256);
zde._BitField = (short)(block[i++] + block[i++] * 256);
zde._CompressionMethod = (Int16)(block[i++] + block[i++] * 256);
zde._TimeBlob = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
zde._LastModified = SharedUtilities.PackedToDateTime(zde._TimeBlob);
zde._timestamp |= ZipEntryTimestamp.DOS;
zde._Crc32 = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
zde._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
zde._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
}
// preserve
zde._CompressionMethod_FromZipFile = zde._CompressionMethod;
zde._filenameLength = (short)(block[i++] + block[i++] * 256);
zde._extraFieldLength = (short)(block[i++] + block[i++] * 256);
zde._commentLength = (short)(block[i++] + block[i++] * 256);
zde._diskNumber = (UInt32)(block[i++] + block[i++] * 256);
zde._InternalFileAttrs = (short)(block[i++] + block[i++] * 256);
zde._ExternalFileAttrs = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
zde._RelativeOffsetOfLocalHeader = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
// workitem 7801
zde.IsText = ((zde._InternalFileAttrs & 0x01) == 0x01);
block = new byte[zde._filenameLength];
n = s.Read(block, 0, block.Length);
bytesRead += n;
if ((zde._BitField & 0x0800) == 0x0800)
{
// UTF-8 is in use
zde._FileNameInArchive = SharedUtilities.Utf8StringFromBuffer(block);
}
else
{
zde._FileNameInArchive = SharedUtilities.StringFromBuffer(block, expectedEncoding);
}
// workitem 10330
// insure unique entry names
while (previouslySeen.ContainsKey(zde._FileNameInArchive))
{
zde._FileNameInArchive = CopyHelper.AppendCopyToFileName(zde._FileNameInArchive);
zde._metadataChanged = true;
}
if (zde.AttributesIndicateDirectory)
{
zde.MarkAsDirectory(); // may append a slash to filename if nec.
}
// workitem 6898
else if (zde._FileNameInArchive.EndsWith("/"))
{
zde.MarkAsDirectory();
}
zde._CompressedFileDataSize = zde._CompressedSize;
if ((zde._BitField & 0x01) == 0x01)
{
// this may change after processing the Extra field
zde._Encryption_FromZipFile = zde._Encryption =
EncryptionAlgorithm.PkzipWeak;
zde._sourceIsEncrypted = true;
}
if (zde._extraFieldLength > 0)
{
zde._InputUsesZip64 = (zde._CompressedSize == 0xFFFFFFFF ||
zde._UncompressedSize == 0xFFFFFFFF ||
zde._RelativeOffsetOfLocalHeader == 0xFFFFFFFF);
// Console.WriteLine(" Input uses Z64?: {0}", zde._InputUsesZip64);
bytesRead += zde.ProcessExtraField(s, zde._extraFieldLength);
zde._CompressedFileDataSize = zde._CompressedSize;
}
// we've processed the extra field, so we know the encryption method is set now.
if (zde._Encryption == EncryptionAlgorithm.PkzipWeak)
{
// the "encryption header" of 12 bytes precedes the file data
zde._CompressedFileDataSize -= 12;
}
#if AESCRYPTO
else if (zde.Encryption == EncryptionAlgorithm.WinZipAes128 ||
zde.Encryption == EncryptionAlgorithm.WinZipAes256)
{
zde._CompressedFileDataSize = zde.CompressedSize -
(ZipEntry.GetLengthOfCryptoHeaderBytes(zde.Encryption) + 10);
zde._LengthOfTrailer = 10;
}
#endif
// tally the trailing descriptor
if ((zde._BitField & 0x0008) == 0x0008)
{
// sig, CRC, Comp and Uncomp sizes
if (zde._InputUsesZip64)
{
zde._LengthOfTrailer += 24;
}
else
{
zde._LengthOfTrailer += 16;
}
}
// workitem 12744
zde.AlternateEncoding = ((zde._BitField & 0x0800) == 0x0800)
? System.Text.Encoding.UTF8
:expectedEncoding;
zde.AlternateEncodingUsage = ZipOption.Always;
if (zde._commentLength > 0)
{
block = new byte[zde._commentLength];
n = s.Read(block, 0, block.Length);
bytesRead += n;
if ((zde._BitField & 0x0800) == 0x0800)
{
// UTF-8 is in use
zde._Comment = SharedUtilities.Utf8StringFromBuffer(block);
}
else
{
zde._Comment = SharedUtilities.StringFromBuffer(block, expectedEncoding);
}
}
//zde._LengthOfDirEntry = bytesRead;
return(zde);
}
private static bool ReadHeader(ZipEntry ze, System.Text.Encoding defaultEncoding)
{
int bytesRead = 0;
// change for workitem 8098
ze._RelativeOffsetOfLocalHeader = ze.ArchiveStream.Position;
int signature = SharedUtilities.ReadEntrySignature(ze.ArchiveStream);
bytesRead += 4;
// Return false if this is not a local file header signature.
if (ZipEntry.IsNotValidSig(signature))
{
// Getting "not a ZipEntry signature" is not always wrong or an error.
// This will happen after the last entry in a zipfile. In that case, we
// expect to read :
// a ZipDirEntry signature (if a non-empty zip file) or
// a ZipConstants.EndOfCentralDirectorySignature.
//
// Anything else is a surprise.
ze.ArchiveStream.Seek(-4, SeekOrigin.Current); // unread the signature
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream);
if (ZipEntry.IsNotValidZipDirEntrySig(signature) && (signature != ZipConstants.EndOfCentralDirectorySignature))
{
throw new BadReadException(String.Format(" Bad signature (0x{0:X8}) at position 0x{1:X8}", signature, ze.ArchiveStream.Position));
}
return(false);
}
byte[] block = new byte[26];
int n = ze.ArchiveStream.Read(block, 0, block.Length);
if (n != block.Length)
{
return(false);
}
bytesRead += n;
int i = 0;
ze._VersionNeeded = (Int16)(block[i++] + block[i++] * 256);
ze._BitField = (Int16)(block[i++] + block[i++] * 256);
ze._CompressionMethod_FromZipFile = ze._CompressionMethod = (Int16)(block[i++] + block[i++] * 256);
ze._TimeBlob = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
// transform the time data into something usable (a DateTime)
ze._LastModified = SharedUtilities.PackedToDateTime(ze._TimeBlob);
ze._timestamp |= ZipEntryTimestamp.DOS;
if ((ze._BitField & 0x01) == 0x01)
{
ze._Encryption_FromZipFile = ze._Encryption = EncryptionAlgorithm.PkzipWeak; // this *may* change after processing the Extra field
ze._sourceIsEncrypted = true;
}
// NB: if ((ze._BitField & 0x0008) != 0x0008), then the Compressed, uncompressed and
// CRC values are not true values; the true values will follow the entry data.
// But, regardless of the status of bit 3 in the bitfield, the slots for
// the three amigos may contain marker values for ZIP64. So we must read them.
{
ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
if ((uint)ze._CompressedSize == 0xFFFFFFFF ||
(uint)ze._UncompressedSize == 0xFFFFFFFF)
{
ze._InputUsesZip64 = true;
}
}
Int16 filenameLength = (short)(block[i++] + block[i++] * 256);
Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256);
block = new byte[filenameLength];
n = ze.ArchiveStream.Read(block, 0, block.Length);
bytesRead += n;
// if the UTF8 bit is set for this entry, override the
// encoding the application requested.
if ((ze._BitField & 0x0800) == 0x0800)
{
// workitem 12744
ze.AlternateEncoding = System.Text.Encoding.UTF8;
ze.AlternateEncodingUsage = ZipOption.Always;
}
// need to use this form of GetString() for .NET CF
ze._FileNameInArchive = ze.AlternateEncoding.GetString(block, 0, block.Length);
// workitem 6898
if (ze._FileNameInArchive.EndsWith("/"))
{
ze.MarkAsDirectory();
}
bytesRead += ze.ProcessExtraField(ze.ArchiveStream, extraFieldLength);
ze._LengthOfTrailer = 0;
// workitem 6607 - don't read for directories
// actually get the compressed size and CRC if necessary
if (!ze._FileNameInArchive.EndsWith("/") && (ze._BitField & 0x0008) == 0x0008)
{
// This descriptor exists only if bit 3 of the general
// purpose bit flag is set (see below). It is byte aligned
// and immediately follows the last byte of compressed data,
// as well as any encryption trailer, as with AES.
// This descriptor is used only when it was not possible to
// seek in the output .ZIP file, e.g., when the output .ZIP file
// was standard output or a non-seekable device. For ZIP64(tm) format
// archives, the compressed and uncompressed sizes are 8 bytes each.
// workitem 8098: ok (restore)
long posn = ze.ArchiveStream.Position;
// Here, we're going to loop until we find a ZipEntryDataDescriptorSignature and
// a consistent data record after that. To be consistent, the data record must
// indicate the length of the entry data.
bool wantMore = true;
long SizeOfDataRead = 0;
int tries = 0;
while (wantMore)
{
tries++;
// We call the FindSignature shared routine to find the specified signature
// in the already-opened zip archive, starting from the current cursor
// position in that filestream. If we cannot find the signature, then the
// routine returns -1, and the ReadHeader() method returns false,
// indicating we cannot read a legal entry header. If we have found it,
// then the FindSignature() method returns the number of bytes in the
// stream we had to seek forward, to find the sig. We need this to
// determine if the zip entry is valid, later.
if (ze._container.ZipFile != null)
{
ze._container.ZipFile.OnReadBytes(ze);
}
long d = SharedUtilities.FindSignature(ze.ArchiveStream, ZipConstants.ZipEntryDataDescriptorSignature);
if (d == -1)
{
return(false);
}
// total size of data read (through all loops of this).
SizeOfDataRead += d;
if (ze._InputUsesZip64)
{
// read 1x 4-byte (CRC) and 2x 8-bytes (Compressed Size, Uncompressed Size)
block = new byte[20];
n = ze.ArchiveStream.Read(block, 0, block.Length);
if (n != 20)
{
return(false);
}
// do not increment bytesRead - it is for entry header only.
// the data we have just read is a footer (falls after the file data)
//bytesRead += n;
i = 0;
ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._CompressedSize = BitConverter.ToInt64(block, i);
i += 8;
ze._UncompressedSize = BitConverter.ToInt64(block, i);
i += 8;
ze._LengthOfTrailer += 24; // bytes including sig, CRC, Comp and Uncomp sizes
}
else
{
// read 3x 4-byte fields (CRC, Compressed Size, Uncompressed Size)
block = new byte[12];
n = ze.ArchiveStream.Read(block, 0, block.Length);
if (n != 12)
{
return(false);
}
// do not increment bytesRead - it is for entry header only.
// the data we have just read is a footer (falls after the file data)
//bytesRead += n;
i = 0;
ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
ze._LengthOfTrailer += 16; // bytes including sig, CRC, Comp and Uncomp sizes
}
wantMore = (SizeOfDataRead != ze._CompressedSize);
if (wantMore)
{
// Seek back to un-read the last 12 bytes - maybe THEY contain
// the ZipEntryDataDescriptorSignature.
// (12 bytes for the CRC, Comp and Uncomp size.)
ze.ArchiveStream.Seek(-12, SeekOrigin.Current);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream);
// Adjust the size to account for the false signature read in
// FindSignature().
SizeOfDataRead += 4;
}
}
// seek back to previous position, to prepare to read file data
// workitem 8098: ok (restore)
ze.ArchiveStream.Seek(posn, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream);
}
ze._CompressedFileDataSize = ze._CompressedSize;
// bit 0 set indicates that some kind of encryption is in use
if ((ze._BitField & 0x01) == 0x01)
{
#if AESCRYPTO
if (ze.Encryption == EncryptionAlgorithm.WinZipAes128 ||
ze.Encryption == EncryptionAlgorithm.WinZipAes256)
{
int bits = ZipEntry.GetKeyStrengthInBits(ze._Encryption_FromZipFile);
// read in the WinZip AES metadata: salt + PV. 18 bytes for AES256. 10 bytes for AES128.
ze._aesCrypto_forExtract = WinZipAesCrypto.ReadFromStream(null, bits, ze.ArchiveStream);
bytesRead += ze._aesCrypto_forExtract.SizeOfEncryptionMetadata - 10; // MAC (follows crypto bytes)
// according to WinZip, the CompressedSize includes the AES Crypto framing data.
ze._CompressedFileDataSize -= ze._aesCrypto_forExtract.SizeOfEncryptionMetadata;
ze._LengthOfTrailer += 10; // MAC
}
else
#endif
{
// read in the header data for "weak" encryption
ze._WeakEncryptionHeader = new byte[12];
bytesRead += ZipEntry.ReadWeakEncryptionHeader(ze._archiveStream, ze._WeakEncryptionHeader);
// decrease the filedata size by 12 bytes
ze._CompressedFileDataSize -= 12;
}
}
// Remember the size of the blob for this entry.
// We also have the starting position in the stream for this entry.
ze._LengthOfHeader = bytesRead;
ze._TotalEntrySize = ze._LengthOfHeader + ze._CompressedFileDataSize + ze._LengthOfTrailer;
// We've read in the regular entry header, the extra field, and any
// encryption header. The pointer in the file is now at the start of the
// filedata, which is potentially compressed and encrypted. Just ahead in
// the file, there are _CompressedFileDataSize bytes of data, followed by
// potentially a non-zero length trailer, consisting of optionally, some
// encryption stuff (10 byte MAC for AES), and the bit-3 trailer (16 or 24
// bytes).
return(true);
}
public long TruncateBackward(uint diskNumber, long offset)
{
// Console.WriteLine("***ZSS.Trunc to disk {0}", diskNumber);
// Console.WriteLine("***ZSS.Trunc: current disk {0}", CurrentSegment);
if (diskNumber >= 99)
{
throw new ArgumentOutOfRangeException("diskNumber");
}
if (rwMode != RwMode.Write)
{
_exceptionPending = true;
throw new ZipException("bad state.");
}
// Seek back in the segmented stream to a (maybe) prior segment.
// Check if it is the same segment. If it is, very simple.
if (diskNumber == CurrentSegment)
{
var x = _innerStream.Seek(offset, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_innerStream);
return(x);
}
// Seeking back to a prior segment.
// The current segment and any intervening segments must be removed.
// First, close the current segment, and then remove it.
if (_innerStream != null)
{
#if NETCF
_innerStream.Close();
#else
_innerStream.Dispose();
#endif
if (File.Exists(_currentTempName))
{
File.Delete(_currentTempName);
}
}
// Now, remove intervening segments.
for (uint j = CurrentSegment - 1; j > diskNumber; j--)
{
string s = _NameForSegment(j);
// Console.WriteLine("***ZSS.Trunc: removing file {0}", s);
if (File.Exists(s))
{
File.Delete(s);
}
}
// now, open the desired segment. It must exist.
CurrentSegment = diskNumber;
// get a new temp file, try 3 times:
for (int i = 0; i < 3; i++)
{
try
{
_currentTempName = SharedUtilities.InternalGetTempFileName();
// move the .z0x file back to a temp name
File.Move(CurrentName, _currentTempName);
break; // workitem 12403
}
catch (IOException)
{
if (i == 2)
{
throw;
}
}
}
// open it
_innerStream = new FileStream(_currentTempName, FileMode.Open);
var r = _innerStream.Seek(offset, SeekOrigin.Begin);
// workitem 10178
SharedUtilities.Workaround_Ladybug318918(_innerStream);
return(r);
}