示例#1
0
文件: ZipEntry.cs 项目: avs009/gsf
		/// <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 = System.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 System.DateTime ( 1970, 1, 1, 0, 0, 0 ).ToUniversalTime() +
						new TimeSpan ( 0, 0, 0, iTime, 0 )).ToLocalTime();
				}
			}
		}