private void ReadCentralDirectory() { try { // assume ReadEndOfCentralDirectory has been called and has populated _centralDirectoryStart _archiveStream.Seek(_centralDirectoryStart, SeekOrigin.Begin); long numberOfEntries = 0; //read the central directory ZipCentralDirectoryFileHeader currentHeader; bool saveExtraFieldsAndComments = Mode == ZipArchiveMode.Update; while (ZipCentralDirectoryFileHeader.TryReadBlock(_archiveReader, saveExtraFieldsAndComments, out currentHeader)) { AddEntry(new ReadOnlyZipArchiveEntry(this, currentHeader)); numberOfEntries++; } if (numberOfEntries != _expectedNumberOfEntries) { throw new InvalidDataException("NumEntriesWrong"); } } catch (EndOfStreamException ex) { throw new InvalidDataException("CentralDirectoryInvalid", ex); } }
// Initializes, attaches it to archive internal ReadOnlyZipArchiveEntry(ReadOnlyZipArchive archive, ZipCentralDirectoryFileHeader cd) { _archive = archive; _originallyInArchive = true; _diskNumberStart = cd.DiskNumberStart; _versionMadeByPlatform = ( ZipVersionMadeByPlatform )cd.VersionMadeByCompatibility; _versionMadeBySpecification = ( ZipVersionNeededValues )cd.VersionMadeBySpecification; _versionToExtract = ( ZipVersionNeededValues )cd.VersionNeededToExtract; _generalPurposeBitFlag = ( BitFlagValues )cd.GeneralPurposeBitFlag; CompressionMethod = ( CompressionMethodValues )cd.CompressionMethod; _lastModified = new DateTimeOffset(ZipHelper.DosTimeToDateTime(cd.LastModified)); _compressedSize = cd.CompressedSize; _uncompressedSize = cd.UncompressedSize; _externalFileAttr = cd.ExternalFileAttributes; _offsetOfLocalHeader = cd.RelativeOffsetOfLocalHeader; // we don't know this yet: should be _offsetOfLocalHeader + 30 + _storedEntryNameBytes.Length + extrafieldlength // but entryname/extra length could be different in LH _storedOffsetOfCompressedData = null; _crc32 = cd.Crc32; _compressedBytes = null; _storedUncompressedData = null; _currentlyOpenForWrite = false; _everOpenedForWrite = false; _outstandingWriteStream = null; FullName = DecodeEntryName(cd.Filename); _lhUnknownExtraFields = null; // the cd should have these as null if we aren't in Update mode _cdUnknownExtraFields = cd.ExtraFields; _fileComment = cd.FileComment; _compressionLevel = null; }
// if saveExtraFieldsAndComments is false, FileComment and ExtraFields will be null // in either case, the zip64 extra field info will be incorporated into other fields public static bool TryReadBlock(BinaryReader reader, bool saveExtraFieldsAndComments, out ZipCentralDirectoryFileHeader header) { header = new ZipCentralDirectoryFileHeader(); if (reader.ReadUInt32() != SignatureConstant) { return(false); } header.VersionMadeBySpecification = reader.ReadByte(); header.VersionMadeByCompatibility = reader.ReadByte(); header.VersionNeededToExtract = reader.ReadUInt16(); header.GeneralPurposeBitFlag = reader.ReadUInt16(); header.CompressionMethod = reader.ReadUInt16(); header.LastModified = reader.ReadUInt32(); header.Crc32 = reader.ReadUInt32(); uint compressedSizeSmall = reader.ReadUInt32(); uint uncompressedSizeSmall = reader.ReadUInt32(); header.FilenameLength = reader.ReadUInt16(); header.ExtraFieldLength = reader.ReadUInt16(); header.FileCommentLength = reader.ReadUInt16(); ushort diskNumberStartSmall = reader.ReadUInt16(); header.InternalFileAttributes = reader.ReadUInt16(); header.ExternalFileAttributes = reader.ReadUInt32(); uint relativeOffsetOfLocalHeaderSmall = reader.ReadUInt32(); header.Filename = reader.ReadBytes(header.FilenameLength); bool uncompressedSizeInZip64 = uncompressedSizeSmall == ZipHelper.Mask32Bit; bool compressedSizeInZip64 = compressedSizeSmall == ZipHelper.Mask32Bit; bool relativeOffsetInZip64 = relativeOffsetOfLocalHeaderSmall == ZipHelper.Mask32Bit; bool diskNumberStartInZip64 = diskNumberStartSmall == ZipHelper.Mask16Bit; Zip64ExtraField zip64; long endExtraFields = reader.BaseStream.Position + header.ExtraFieldLength; using (Stream str = new SubReadStream(reader.BaseStream, reader.BaseStream.Position, header.ExtraFieldLength)) { if (saveExtraFieldsAndComments) { header.ExtraFields = ZipGenericExtraField.ParseExtraField(str); zip64 = Zip64ExtraField.GetAndRemoveZip64Block(header.ExtraFields, uncompressedSizeInZip64, compressedSizeInZip64, relativeOffsetInZip64, diskNumberStartInZip64); } else { header.ExtraFields = null; zip64 = Zip64ExtraField.GetJustZip64Block(str, uncompressedSizeInZip64, compressedSizeInZip64, relativeOffsetInZip64, diskNumberStartInZip64); } } // There are zip files that have malformed ExtraField blocks in which GetJustZip64Block() silently bails out without reading all the way to the end // of the ExtraField block. Thus we must force the stream's position to the proper place. reader.BaseStream.AdvanceToPosition(endExtraFields); if (saveExtraFieldsAndComments) { header.FileComment = reader.ReadBytes(header.FileCommentLength); } else { reader.BaseStream.Position += header.FileCommentLength; header.FileComment = null; } header.UncompressedSize = zip64.UncompressedSize == null ? uncompressedSizeSmall : zip64.UncompressedSize.Value; header.CompressedSize = zip64.CompressedSize == null ? compressedSizeSmall : zip64.CompressedSize.Value; header.RelativeOffsetOfLocalHeader = zip64.LocalHeaderOffset == null ? relativeOffsetOfLocalHeaderSmall : zip64.LocalHeaderOffset.Value; header.DiskNumberStart = zip64.StartDiskNumber == null ? diskNumberStartSmall : zip64.StartDiskNumber.Value; return(true); }