Example #1
0
		private void WriteLocalEntryHeader(ZipUpdate update)
		{
			ZipEntry entry = update.OutEntry;

			// TODO: Local offset will require adjusting for multi-disk zip files.
			entry.Offset = baseStream_.Position;

			// TODO: Need to clear any entry flags that dont make sense or throw an exception here.
			if (update.Command != UpdateCommand.Copy)
			{
				if (entry.CompressionMethod == CompressionMethod.Deflated)
				{
					if (entry.Size == 0)
					{
						// No need to compress - no data.
						entry.CompressedSize = entry.Size;
						entry.Crc = 0;
						entry.CompressionMethod = CompressionMethod.Stored;
					}
				}
				else if (entry.CompressionMethod == CompressionMethod.Stored)
				{
					entry.Flags &= ~(int) GeneralBitFlags.Descriptor;
				}

				if (HaveKeys)
				{
					entry.IsCrypted = true;
					if (entry.Crc < 0)
					{
						entry.Flags |= (int) GeneralBitFlags.Descriptor;
					}
				}
				else
				{
					entry.IsCrypted = false;
				}

				switch (useZip64_)
				{
					case UseZip64.Dynamic:
						if (entry.Size < 0)
						{
							entry.ForceZip64();
						}
						break;

					case UseZip64.On:
						entry.ForceZip64();
						break;

					case UseZip64.Off:
						// Do nothing.  The entry itself may be using Zip64 independantly.
						break;
				}
			}

			// Write the local file header
			WriteLEInt(ZipConstants.LocalHeaderSignature);

			WriteLEShort(entry.Version);
			WriteLEShort(entry.Flags);

			WriteLEShort((byte) entry.CompressionMethod);
			WriteLEInt((int) entry.DosTime);

			if (!entry.HasCrc)
			{
				// Note patch address for updating CRC later.
				update.CrcPatchOffset = baseStream_.Position;
				WriteLEInt(0);
			}
			else
			{
				WriteLEInt(unchecked((int) entry.Crc));
			}

			if (entry.LocalHeaderRequiresZip64)
			{
				WriteLEInt(-1);
				WriteLEInt(-1);
			}
			else
			{
				if ((entry.CompressedSize < 0) || (entry.Size < 0))
				{
					update.SizePatchOffset = baseStream_.Position;
				}

				WriteLEInt((int) entry.CompressedSize);
				WriteLEInt((int) entry.Size);
			}

			byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);

			if (name.Length > 0xFFFF)
			{
				throw new ZipException("Entry name too long.");
			}

			ZipExtraData ed = new ZipExtraData(entry.ExtraData);

			if (entry.LocalHeaderRequiresZip64)
			{
				ed.StartNewEntry();

				// Local entry header always includes size and compressed size.
				// NOTE the order of these fields is reversed when compared to the normal headers!
				ed.AddLeLong(entry.Size);
				ed.AddLeLong(entry.CompressedSize);
				ed.AddNewEntry(1);
			}
			else
			{
				ed.Delete(1);
			}

			entry.ExtraData = ed.GetEntryData();

			WriteLEShort(name.Length);
			WriteLEShort(entry.ExtraData.Length);

			if (name.Length > 0)
			{
				baseStream_.Write(name, 0, name.Length);
			}

			if (entry.LocalHeaderRequiresZip64)
			{
				if (!ed.Find(1))
				{
					throw new ZipException("Internal error cannot find extra data");
				}

				update.SizePatchOffset = baseStream_.Position + ed.CurrentReadIndex;
			}

			if (entry.ExtraData.Length > 0)
			{
				baseStream_.Write(entry.ExtraData, 0, entry.ExtraData.Length);
			}
		}
Example #2
0
		private int WriteCentralDirectoryHeader(ZipEntry entry)
		{
			if (entry.CompressedSize < 0)
			{
				throw new ZipException("Attempt to write central directory entry with unknown csize");
			}

			if (entry.Size < 0)
			{
				throw new ZipException("Attempt to write central directory entry with unknown size");
			}

			if (entry.Crc < 0)
			{
				throw new ZipException("Attempt to write central directory entry with unknown crc");
			}

			// Write the central file header
			WriteLEInt(ZipConstants.CentralHeaderSignature);

			// Version made by
			WriteLEShort(ZipConstants.VersionMadeBy);

			// Version required to extract
			WriteLEShort(entry.Version);

			WriteLEShort(entry.Flags);

			unchecked
			{
				WriteLEShort((byte) entry.CompressionMethod);
				WriteLEInt((int) entry.DosTime);
				WriteLEInt((int) entry.Crc);
			}

			if ((entry.IsZip64Forced()) || (entry.CompressedSize >= 0xffffffff))
			{
				WriteLEInt(-1);
			}
			else
			{
				WriteLEInt((int) (entry.CompressedSize & 0xffffffff));
			}

			if ((entry.IsZip64Forced()) || (entry.Size >= 0xffffffff))
			{
				WriteLEInt(-1);
			}
			else
			{
				WriteLEInt((int) entry.Size);
			}

			byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);

			if (name.Length > 0xFFFF)
			{
				throw new ZipException("Entry name is too long.");
			}

			WriteLEShort(name.Length);

			// Central header extra data is different to local header version so regenerate.
			ZipExtraData ed = new ZipExtraData(entry.ExtraData);

			if (entry.CentralHeaderRequiresZip64)
			{
				ed.StartNewEntry();

				if ((entry.Size >= 0xffffffff) || (useZip64_ == UseZip64.On))
				{
					ed.AddLeLong(entry.Size);
				}

				if ((entry.CompressedSize >= 0xffffffff) || (useZip64_ == UseZip64.On))
				{
					ed.AddLeLong(entry.CompressedSize);
				}

				if (entry.Offset >= 0xffffffff)
				{
					ed.AddLeLong(entry.Offset);
				}

				// Number of disk on which this file starts isnt supported and is never written here.
				ed.AddNewEntry(1);
			}
			else
			{
				// Should have already be done when local header was added.
				ed.Delete(1);
			}

			byte[] centralExtraData = ed.GetEntryData();

			WriteLEShort(centralExtraData.Length);
			WriteLEShort(entry.Comment != null ? entry.Comment.Length : 0);

			WriteLEShort(0); // disk number
			WriteLEShort(0); // internal file attributes

			// External file attributes...
			if (entry.ExternalFileAttributes != -1)
			{
				WriteLEInt(entry.ExternalFileAttributes);
			}
			else
			{
				if (entry.IsDirectory)
				{
					WriteLEUint(16);
				}
				else
				{
					WriteLEUint(0);
				}
			}

			if (entry.Offset >= 0xffffffff)
			{
				WriteLEUint(0xffffffff);
			}
			else
			{
				WriteLEUint((uint) (int) entry.Offset);
			}

			if (name.Length > 0)
			{
				baseStream_.Write(name, 0, name.Length);
			}

			if (centralExtraData.Length > 0)
			{
				baseStream_.Write(centralExtraData, 0, centralExtraData.Length);
			}

			byte[] rawComment = (entry.Comment != null) ? Encoding.ASCII.GetBytes(entry.Comment) : new byte[0];

			if (rawComment.Length > 0)
			{
				baseStream_.Write(rawComment, 0, rawComment.Length);
			}

			return ZipConstants.CentralHeaderBaseSize + name.Length + centralExtraData.Length + rawComment.Length;
		}
Example #3
0
		/// <summary>
		/// Test a local header against that provided from the central directory
		/// </summary>
		/// <param name="entry">
		/// The entry to test against
		/// </param>
		/// <param name="tests">The type of <see cref="HeaderTest">tests</see> to carry out.</param>
		/// <returns>The offset of the entries data in the file</returns>
		private long TestLocalHeader(ZipEntry entry, HeaderTest tests)
		{
			lock (baseStream_)
			{
				bool testHeader = (tests & HeaderTest.Header) != 0;
				bool testData = (tests & HeaderTest.Extract) != 0;

				baseStream_.Seek(offsetOfFirstEntry + entry.Offset, SeekOrigin.Begin);
				if ((int) ReadLEUint() != ZipConstants.LocalHeaderSignature)
				{
					throw new ZipException(string.Format("Wrong local header signature @{0:X}", offsetOfFirstEntry + entry.Offset));
				}

				short extractVersion = (short) ReadLEUshort();
				short localFlags = (short) ReadLEUshort();
				short compressionMethod = (short) ReadLEUshort();
				short fileTime = (short) ReadLEUshort();
				short fileDate = (short) ReadLEUshort();
				uint crcValue = ReadLEUint();
				long compressedSize = ReadLEUint();
				long size = ReadLEUint();
				int storedNameLength = ReadLEUshort();
				int extraDataLength = ReadLEUshort();

				byte[] nameData = new byte[storedNameLength];
				StreamUtils.ReadFully(baseStream_, nameData);

				byte[] extraData = new byte[extraDataLength];
				StreamUtils.ReadFully(baseStream_, extraData);

				ZipExtraData ed = new ZipExtraData(extraData);

				// Extra data / zip64 checks
				if (ed.Find(1))
				{
					// TODO Check for tag values being distinct..  Multiple zip64 tags means what?

					// Zip64 extra data but 'extract version' is too low
					if (extractVersion < ZipConstants.VersionZip64)
					{
						throw new ZipException(
							string.Format("Extra data contains Zip64 information but version {0}.{1} is not high enough",
							              extractVersion/10, extractVersion%10));
					}

					// Zip64 extra data but size fields dont indicate its required.
					if (((uint) size != uint.MaxValue) && ((uint) compressedSize != uint.MaxValue))
					{
						throw new ZipException("Entry sizes not correct for Zip64");
					}

					size = ed.ReadLong();
					compressedSize = ed.ReadLong();
				}
				else
				{
					// No zip64 extra data but entry requires it.
					if ((extractVersion >= ZipConstants.VersionZip64) &&
					    (((uint) size == uint.MaxValue) || ((uint) compressedSize == uint.MaxValue)))
					{
						throw new ZipException("Required Zip64 extended information missing");
					}
				}

				if (testData)
				{
					if (entry.IsFile)
					{
						if (!entry.IsCompressionMethodSupported())
						{
							throw new ZipException("Compression method not supported");
						}

						if ((extractVersion > ZipConstants.VersionMadeBy)
						    || ((extractVersion > 20) && (extractVersion < ZipConstants.VersionZip64)))
						{
							throw new ZipException(string.Format("Version required to extract this entry not supported ({0})", extractVersion));
						}

						if ((localFlags & (int) (GeneralBitFlags.Patched | GeneralBitFlags.StrongEncryption | GeneralBitFlags.EnhancedCompress | GeneralBitFlags.HeaderMasked)) != 0)
						{
							throw new ZipException("The library does not support the zip version required to extract this entry");
						}
					}
				}

				if (testHeader)
				{
					if ((extractVersion <= 63) && // Ignore later versions as we dont know about them..
					    (extractVersion != 10) &&
					    (extractVersion != 11) &&
					    (extractVersion != 20) &&
					    (extractVersion != 21) &&
					    (extractVersion != 25) &&
					    (extractVersion != 27) &&
					    (extractVersion != 45) &&
					    (extractVersion != 46) &&
					    (extractVersion != 50) &&
					    (extractVersion != 51) &&
					    (extractVersion != 52) &&
					    (extractVersion != 61) &&
					    (extractVersion != 62) &&
					    (extractVersion != 63)
						)
					{
						throw new ZipException(string.Format("Version required to extract this entry is invalid ({0})", extractVersion));
					}

					// Local entry flags dont have reserved bit set on.
					if ((localFlags & (int) (GeneralBitFlags.ReservedPKware4 | GeneralBitFlags.ReservedPkware14 | GeneralBitFlags.ReservedPkware15)) != 0)
					{
						throw new ZipException("Reserved bit flags cannot be set.");
					}

					// Encryption requires extract version >= 20
					if (((localFlags & (int) GeneralBitFlags.Encrypted) != 0) && (extractVersion < 20))
					{
						throw new ZipException(string.Format("Version required to extract this entry is too low for encryption ({0})", extractVersion));
					}

					// Strong encryption requires encryption flag to be set and extract version >= 50.
					if ((localFlags & (int) GeneralBitFlags.StrongEncryption) != 0)
					{
						if ((localFlags & (int) GeneralBitFlags.Encrypted) == 0)
						{
							throw new ZipException("Strong encryption flag set but encryption flag is not set");
						}

						if (extractVersion < 50)
						{
							throw new ZipException(string.Format("Version required to extract this entry is too low for encryption ({0})", extractVersion));
						}
					}

					// Patched entries require extract version >= 27
					if (((localFlags & (int) GeneralBitFlags.Patched) != 0) && (extractVersion < 27))
					{
						throw new ZipException(string.Format("Patched data requires higher version than ({0})", extractVersion));
					}

					// Central header flags match local entry flags.
					if (localFlags != entry.Flags)
					{
						throw new ZipException("Central header/local header flags mismatch");
					}

					// Central header compression method matches local entry
					if (entry.CompressionMethod != (CompressionMethod) compressionMethod)
					{
						throw new ZipException("Central header/local header compression method mismatch");
					}

					// Strong encryption and extract version match
					if ((localFlags & (int) GeneralBitFlags.StrongEncryption) != 0)
					{
						if (extractVersion < 62)
						{
							throw new ZipException("Strong encryption flag set but version not high enough");
						}
					}

					if ((localFlags & (int) GeneralBitFlags.HeaderMasked) != 0)
					{
						if ((fileTime != 0) || (fileDate != 0))
						{
							throw new ZipException("Header masked set but date/time values non-zero");
						}
					}

					if ((localFlags & (int) GeneralBitFlags.Descriptor) == 0)
					{
						if (crcValue != (uint) entry.Crc)
						{
							throw new ZipException("Central header/local header crc mismatch");
						}
					}

					// Crc valid for empty entry.
					// This will also apply to streamed entries where size isnt known and the header cant be patched
					if ((size == 0) && (compressedSize == 0))
					{
						if (crcValue != 0)
						{
							throw new ZipException("Invalid CRC for empty entry");
						}
					}

					// TODO: make test more correct...  can't compare lengths as was done originally as this can fail for MBCS strings
					// Assuming a code page at this point is not valid?  Best is to store the name length in the ZipEntry probably
					if (entry.Name.Length > storedNameLength)
					{
						throw new ZipException("File name length mismatch");
					}

					// Name data has already been read convert it and compare.
					string localName = ZipConstants.ConvertToStringExt(localFlags, nameData);

					// Central directory and local entry name match
					if (localName != entry.Name)
					{
						throw new ZipException("Central header and local header file name mismatch");
					}

					// Directories have zero size.
					if (entry.IsDirectory)
					{
						if ((compressedSize != 0) || (size != 0))
						{
							throw new ZipException("Directory cannot have size");
						}
					}

					if (!ZipNameTransform.IsValidName(localName, true))
					{
						throw new ZipException("Name is invalid");
					}
				}

				// Tests that apply to both data and header.

				// Size can be verified only if it is known in the local header.
				// it will always be known in the central header.
				if ((localFlags & (int) GeneralBitFlags.Descriptor) == 0 ||
				    (size != 0 || compressedSize != 0))
				{
					if (size != entry.Size)
					{
						throw new ZipException(
							string.Format("Size mismatch between central header({0}) and local header({1})",
							              entry.Size, size));
					}

					if (compressedSize != entry.CompressedSize)
					{
						throw new ZipException(
							string.Format("Compressed size mismatch between central header({0}) and local header({1})",
							              entry.CompressedSize, compressedSize));
					}
				}

				int extraLength = storedNameLength + extraDataLength;
				return offsetOfFirstEntry + entry.Offset + ZipConstants.LocalHeaderBaseSize + extraLength;
			}
		}
		/// <summary>
		/// Finishes the stream.  This will write the central directory at the
		/// end of the zip file and flush the stream.
		/// </summary>
		/// <remarks>
		/// This is automatically called when the stream is closed.
		/// </remarks>
		/// <exception cref="System.IO.IOException">
		/// An I/O error occurs.
		/// </exception>
		/// <exception cref="ZipException">
		/// Comment exceeds the maximum length<br/>
		/// Entry name exceeds the maximum length
		/// </exception>
		public override void Finish()
		{
			if (entries == null)
			{
				return;
			}

			if (curEntry != null)
			{
				CloseEntry();
			}

			long numEntries = entries.Count;
			long sizeEntries = 0;

			foreach (ZipEntry entry in entries)
			{
				WriteLeInt(ZipConstants.CentralHeaderSignature);
				WriteLeShort(ZipConstants.VersionMadeBy);
				WriteLeShort(entry.Version);
				WriteLeShort(entry.Flags);
				WriteLeShort((short) entry.CompressionMethod);
				WriteLeInt((int) entry.DosTime);
				WriteLeInt((int) entry.Crc);

				if (entry.IsZip64Forced() ||
				    (entry.CompressedSize >= uint.MaxValue))
				{
					WriteLeInt(-1);
				}
				else
				{
					WriteLeInt((int) entry.CompressedSize);
				}

				if (entry.IsZip64Forced() ||
				    (entry.Size >= uint.MaxValue))
				{
					WriteLeInt(-1);
				}
				else
				{
					WriteLeInt((int) entry.Size);
				}

				byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);

				if (name.Length > 0xffff)
				{
					throw new ZipException("Name too long.");
				}

				ZipExtraData ed = new ZipExtraData(entry.ExtraData);

				if (entry.CentralHeaderRequiresZip64)
				{
					ed.StartNewEntry();
					if (entry.IsZip64Forced() ||
					    (entry.Size >= 0xffffffff))
					{
						ed.AddLeLong(entry.Size);
					}

					if (entry.IsZip64Forced() ||
					    (entry.CompressedSize >= 0xffffffff))
					{
						ed.AddLeLong(entry.CompressedSize);
					}

					if (entry.Offset >= 0xffffffff)
					{
						ed.AddLeLong(entry.Offset);
					}

					ed.AddNewEntry(1);
				}
				else
				{
					ed.Delete(1);
				}

				byte[] extra = ed.GetEntryData();

				byte[] entryComment =
					(entry.Comment != null) ?
					                        	ZipConstants.ConvertToArray(entry.Flags, entry.Comment) :
					                        	                                                        	new byte[0];

				if (entryComment.Length > 0xffff)
				{
					throw new ZipException("Comment too long.");
				}

				WriteLeShort(name.Length);
				WriteLeShort(extra.Length);
				WriteLeShort(entryComment.Length);
				WriteLeShort(0); // disk number
				WriteLeShort(0); // internal file attributes
				// external file attributes

				if (entry.ExternalFileAttributes != -1)
				{
					WriteLeInt(entry.ExternalFileAttributes);
				}
				else
				{
					if (entry.IsDirectory)
					{
						// mark entry as directory (from nikolam.AT.perfectinfo.com)
						WriteLeInt(16);
					}
					else
					{
						WriteLeInt(0);
					}
				}

				if (entry.Offset >= uint.MaxValue)
				{
					WriteLeInt(-1);
				}
				else
				{
					WriteLeInt((int) entry.Offset);
				}

				if (name.Length > 0)
				{
					baseOutputStream_.Write(name, 0, name.Length);
				}

				if (extra.Length > 0)
				{
					baseOutputStream_.Write(extra, 0, extra.Length);
				}

				if (entryComment.Length > 0)
				{
					baseOutputStream_.Write(entryComment, 0, entryComment.Length);
				}

				sizeEntries += ZipConstants.CentralHeaderBaseSize + name.Length + extra.Length + entryComment.Length;
			}

			using (ZipHelperStream zhs = new ZipHelperStream(baseOutputStream_))
			{
				zhs.WriteEndOfCentralDirectory(numEntries, sizeEntries, offset, zipComment);
			}

			entries = null;
		}
		/// <summary>
		/// Starts a new Zip entry. It automatically closes the previous
		/// entry if present.
		/// All entry elements bar name are optional, but must be correct if present.
		/// If the compression method is stored and the output is not patchable
		/// the compression for that entry is automatically changed to deflate level 0
		/// </summary>
		/// <param name="entry">
		/// the entry.
		/// </param>
		/// <exception cref="System.ArgumentNullException">
		/// if entry passed is null.
		/// </exception>
		/// <exception cref="System.IO.IOException">
		/// if an I/O error occured.
		/// </exception>
		/// <exception cref="System.InvalidOperationException">
		/// if stream was finished
		/// </exception>
		/// <exception cref="ZipException">
		/// Too many entries in the Zip file<br/>
		/// Entry name is too long<br/>
		/// Finish has already been called<br/>
		/// </exception>
		public void PutNextEntry(ZipEntry entry)
		{
			if (entry == null)
			{
				throw new ArgumentNullException("entry");
			}

			if (entries == null)
			{
				throw new InvalidOperationException("ZipOutputStream was finished");
			}

			if (curEntry != null)
			{
				CloseEntry();
			}

			if (entries.Count == int.MaxValue)
			{
				throw new ZipException("Too many entries for Zip file");
			}

			CompressionMethod method = entry.CompressionMethod;
			int compressionLevel = defaultCompressionLevel;

			// Clear flags that the library manages internally
			entry.Flags &= (int) GeneralBitFlags.UnicodeText;
			patchEntryHeader = false;
			bool headerInfoAvailable = true;

			if (method == CompressionMethod.Stored)
			{
				// Cant store values in a data descriptor as you cant extract stored files
				// if the length isnt known.
				entry.Flags &= ~8;
				if (entry.CompressedSize >= 0)
				{
					if (entry.Size < 0)
					{
						entry.Size = entry.CompressedSize;
					}
					else if (entry.Size != entry.CompressedSize)
					{
						throw new ZipException("Method STORED, but compressed size != size");
					}
				}
				else
				{
					if (entry.Size >= 0)
					{
						entry.CompressedSize = entry.Size;
					}
				}

				if (entry.Size < 0 || entry.Crc < 0)
				{
					if (CanPatchEntries)
					{
						headerInfoAvailable = false;
					}
					else
					{
						// Can't patch entries so storing is not possible.
						method = CompressionMethod.Deflated;
						compressionLevel = 0;
					}
				}
			}

			if (method == CompressionMethod.Deflated)
			{
				if (entry.Size == 0)
				{
					// No need to compress - no data.
					entry.CompressedSize = entry.Size;
					entry.Crc = 0;
					method = CompressionMethod.Stored;
				}
				else if ((entry.CompressedSize < 0) || (entry.Size < 0) || (entry.Crc < 0))
				{
					headerInfoAvailable = false;
				}
			}

			if (headerInfoAvailable == false)
			{
				if (CanPatchEntries == false)
				{
					// Only way to record size and compressed size is to append a data descriptor
					// after compressed data.
					entry.Flags |= 8;
				}
				else
				{
					patchEntryHeader = true;
				}
			}

			if (Password != null)
			{
				entry.IsCrypted = true;
				if (entry.Crc < 0)
				{
					// Need to append a data descriptor as the crc isnt available for use
					// with encryption, the date is used instead.  Setting the flag
					// indicates this to the decompressor.
					entry.Flags |= 8;
				}
			}

			entry.Offset = offset;
			entry.CompressionMethod = method;

			curMethod = method;
			sizePatchPos = -1;

			if ((useZip64_ == UseZip64.On) || ((entry.Size < 0) && (useZip64_ == UseZip64.Dynamic)))
			{
				entry.ForceZip64();
			}

			// Write the local file header
			WriteLeInt(ZipConstants.LocalHeaderSignature);

			WriteLeShort(entry.Version);
			WriteLeShort(entry.Flags);
			WriteLeShort((byte) method);
			WriteLeInt((int) entry.DosTime);

			// TODO: Refactor header writing.  Its done in several places.
			if (headerInfoAvailable)
			{
				WriteLeInt((int) entry.Crc);
				if (entry.LocalHeaderRequiresZip64)
				{
					WriteLeInt(-1);
					WriteLeInt(-1);
				}
				else
				{
					WriteLeInt(entry.IsCrypted ? (int) entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int) entry.CompressedSize);
					WriteLeInt((int) entry.Size);
				}
			}
			else
			{
				if (patchEntryHeader)
				{
					crcPatchPos = baseOutputStream_.Position;
				}
				WriteLeInt(0); // Crc

				if (patchEntryHeader)
				{
					sizePatchPos = baseOutputStream_.Position;
				}

				// For local header both sizes appear in Zip64 Extended Information
				if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
				{
					WriteLeInt(-1);
					WriteLeInt(-1);
				}
				else
				{
					WriteLeInt(0); // Compressed size
					WriteLeInt(0); // Uncompressed size
				}
			}

			byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);

			if (name.Length > 0xFFFF)
			{
				throw new ZipException("Entry name too long.");
			}

			ZipExtraData ed = new ZipExtraData(entry.ExtraData);

			if (entry.LocalHeaderRequiresZip64 && (headerInfoAvailable || patchEntryHeader))
			{
				ed.StartNewEntry();
				if (headerInfoAvailable)
				{
					ed.AddLeLong(entry.Size);
					ed.AddLeLong(entry.CompressedSize);
				}
				else
				{
					ed.AddLeLong(-1);
					ed.AddLeLong(-1);
				}
				ed.AddNewEntry(1);

				if (!ed.Find(1))
				{
					throw new ZipException("Internal error cant find extra data");
				}

				if (patchEntryHeader)
				{
					sizePatchPos = ed.CurrentReadIndex;
				}
			}
			else
			{
				ed.Delete(1);
			}

			byte[] extra = ed.GetEntryData();

			WriteLeShort(name.Length);
			WriteLeShort(extra.Length);

			if (name.Length > 0)
			{
				baseOutputStream_.Write(name, 0, name.Length);
			}

			if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
			{
				sizePatchPos += baseOutputStream_.Position;
			}

			if (extra.Length > 0)
			{
				baseOutputStream_.Write(extra, 0, extra.Length);
			}

			offset += ZipConstants.LocalHeaderBaseSize + name.Length + extra.Length;

			// Activate the entry.
			curEntry = entry;
			crc.Reset();
			if (method == CompressionMethod.Deflated)
			{
				deflater_.Reset();
				deflater_.SetLevel(compressionLevel);
			}
			size = 0;

			if (entry.IsCrypted)
			{
				if (entry.Crc < 0)
				{
					// so testing Zip will says its ok
					WriteEncryptionHeader(entry.DosTime << 16);
				}
				else
				{
					WriteEncryptionHeader(entry.Crc);
				}
			}
		}
		// Write the local file header
		// TODO: ZipHelperStream.WriteLocalHeader is not yet used and needs checking for ZipFile and ZipOuptutStream usage
		private void WriteLocalHeader(ZipEntry entry, EntryPatchData patchData)
		{
			CompressionMethod method = entry.CompressionMethod;
			bool headerInfoAvailable = true; // How to get this?
			bool patchEntryHeader = false;

			WriteLEInt(ZipConstants.LocalHeaderSignature);

			WriteLEShort(entry.Version);
			WriteLEShort(entry.Flags);
			WriteLEShort((byte) method);
			WriteLEInt((int) entry.DosTime);

			if (headerInfoAvailable)
			{
				WriteLEInt((int) entry.Crc);
				if (entry.LocalHeaderRequiresZip64)
				{
					WriteLEInt(-1);
					WriteLEInt(-1);
				}
				else
				{
					WriteLEInt(entry.IsCrypted ? (int) entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int) entry.CompressedSize);
					WriteLEInt((int) entry.Size);
				}
			}
			else
			{
				if (patchData != null)
				{
					patchData.CrcPatchOffset = stream_.Position;
				}
				WriteLEInt(0); // Crc

				if (patchData != null)
				{
					patchData.SizePatchOffset = stream_.Position;
				}

				// For local header both sizes appear in Zip64 Extended Information
				if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
				{
					WriteLEInt(-1);
					WriteLEInt(-1);
				}
				else
				{
					WriteLEInt(0); // Compressed size
					WriteLEInt(0); // Uncompressed size
				}
			}

			byte[] name = ZipConstants.ConvertToArray(entry.Flags, entry.Name);

			if (name.Length > 0xFFFF)
			{
				throw new ZipException("Entry name too long.");
			}

			ZipExtraData ed = new ZipExtraData(entry.ExtraData);

			if (entry.LocalHeaderRequiresZip64 && (headerInfoAvailable || patchEntryHeader))
			{
				ed.StartNewEntry();
				if (headerInfoAvailable)
				{
					ed.AddLeLong(entry.Size);
					ed.AddLeLong(entry.CompressedSize);
				}
				else
				{
					ed.AddLeLong(-1);
					ed.AddLeLong(-1);
				}
				ed.AddNewEntry(1);

				if (!ed.Find(1))
				{
					throw new ZipException("Internal error cant find extra data");
				}

				if (patchData != null)
				{
					patchData.SizePatchOffset = ed.CurrentReadIndex;
				}
			}
			else
			{
				ed.Delete(1);
			}

			byte[] extra = ed.GetEntryData();

			WriteLEShort(name.Length);
			WriteLEShort(extra.Length);

			if (name.Length > 0)
			{
				stream_.Write(name, 0, name.Length);
			}

			if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
			{
				patchData.SizePatchOffset += stream_.Position;
			}

			if (extra.Length > 0)
			{
				stream_.Write(extra, 0, extra.Length);
			}
		}
		/// <summary>
		/// Process extra data fields updating the entry based on the contents.
		/// </summary>
		/// <param name="localHeader">True if the extra data fields should be handled
		/// for a local header, rather than for a central header.
		/// </param>
		internal void ProcessExtraData(bool localHeader)
		{
			ZipExtraData extraData = new ZipExtraData(this.extra);

			if (extraData.Find(0x0001))
			{
				if ((versionToExtract & 0xff) < ZipConstants.VersionZip64)
				{
					throw new ZipException("Zip64 Extended information found but version is not valid");
				}

				// The recorded size will change but remember that this is zip64.
				forceZip64_ = true;

				if (extraData.ValueLength < 4)
				{
					throw new ZipException("Extra data extended Zip64 information length is invalid");
				}

				if (localHeader || (size == uint.MaxValue))
				{
					size = (ulong) extraData.ReadLong();
				}

				if (localHeader || (compressedSize == uint.MaxValue))
				{
					compressedSize = (ulong) extraData.ReadLong();
				}

				if (!localHeader && (offset == uint.MaxValue))
				{
					offset = extraData.ReadLong();
				}
			}
			else
			{
				if (
					((versionToExtract & 0xff) >= ZipConstants.VersionZip64) &&
					((size == uint.MaxValue) || (compressedSize == uint.MaxValue))
					)
				{
					throw new ZipException("Zip64 Extended information required but is missing.");
				}
			}

			if (extraData.Find(10))
			{
				// No room for any tags.
				if (extraData.ValueLength < 8)
				{
					throw new ZipException("NTFS Extra data invalid");
				}

				extraData.ReadInt(); // Reserved

				while (extraData.UnreadCount >= 4)
				{
					int ntfsTag = extraData.ReadShort();
					int ntfsLength = extraData.ReadShort();
					if (ntfsTag == 1)
					{
						if (ntfsLength >= 24)
						{
							long lastModification = extraData.ReadLong();
							long lastAccess = extraData.ReadLong();
							long createTime = extraData.ReadLong();

							DateTime = DateTime.FromFileTime(lastModification);
						}
						break;
					}
					else
					{
						// An unknown NTFS tag so simply skip it.
						extraData.Skip(ntfsLength);
					}
				}
			}
			else if (extraData.Find(0x5455))
			{
				int length = extraData.ValueLength;
				int flags = extraData.ReadByte();

				// Can include other times but these are ignored.  Length of data should
				// actually be 1 + 4 * no of bits in flags.
				if (((flags & 1) != 0) && (length >= 5))
				{
					int iTime = extraData.ReadInt();

					DateTime = (new DateTime(1970, 1, 1, 0, 0, 0).ToUniversalTime() +
					            new TimeSpan(0, 0, 0, iTime, 0)).ToLocalTime();
				}
			}
		}