Exemple #1
0
        /// <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();
                }
            }
        }