// Initializes, attaches it to archive
internal ZipArchiveEntry(ZipArchive archive, ZipCentralDirectoryFileHeader cd)
{
Archive = archive;
_diskNumberStart = cd.DiskNumberStart;
_generalPurposeBitFlag = (BitFlagValues)cd.GeneralPurposeBitFlag;
_compressionMethod = (CompressionMethodValues)cd.CompressionMethod;
// Leave this as a uint and let the caller convert it if it wants (perf optimization)
LastWriteTime = cd.LastModified;
CompressedLength = cd.CompressedSize;
Length = cd.UncompressedSize;
ExternalAttributes = (int)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;
// Sacrifice a slight amount of time for safety. Zips entry names are emphatically NOT supposed to
// have backslashes according to the spec, but they might anyway, so normalize them all to forward slashes.
FullName = DecodeEntryName(cd.Filename)?.Replace('\\', '/') ?? throw new ArgumentNullException(nameof(FullName));
Name = ParseFileName(FullName, (ZipVersionMadeByPlatform)cd.VersionMadeByCompatibility);
}
// Initializes, attaches it to archive
internal ZipArchiveEntry(ZipArchiveFast archive, ZipCentralDirectoryFileHeader cd)
{
Archive = archive;
_diskNumberStart = cd.DiskNumberStart;
_generalPurposeBitFlag = (BitFlagValues)cd.GeneralPurposeBitFlag;
_compressionMethod = (CompressionMethodValues)cd.CompressionMethod;
// Leave this as a uint and let the caller convert it if it wants (perf optimization)
LastWriteTime = cd.LastModified;
CompressedLength = cd.CompressedSize;
Length = cd.UncompressedSize;
_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;
// Sacrifice a slight amount of time for safety. Zips entry names are emphatically NOT supposed to
// have backslashes according to the spec, but they might anyway, so normalize them all to forward slashes.
FullName = DecodeEntryName(cd.Filename).Replace('\\', '/');
// Lazy-load Name so we don't preemptively do a ton of Substring() calls when we don't need to.
_versionMadeByCompatibility = (ZipVersionMadeByPlatform)cd.VersionMadeByCompatibility;
}
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
while (ZipCentralDirectoryFileHeader.TryReadBlock(ArchiveReader, out var currentHeader))
{
AddEntry(new ZipArchiveEntry(this, currentHeader));
numberOfEntries++;
}
if (numberOfEntries != _expectedNumberOfEntries)
{
throw new InvalidDataException(SR.NumEntriesWrong);
}
}
catch (EndOfStreamException ex)
{
throw new InvalidDataException(SR.Format(SR.CentralDirectoryInvalid, ex));
}
}
// if saveExtraFieldsAndComments is false, FileComment and ExtraFields will be null
// in either case, the zip64 extra field info will be incorporated into other fields
internal static bool TryReadBlock(BinaryReader reader, out ZipCentralDirectoryFileHeader header)
{
header = new ZipCentralDirectoryFileHeader();
if (reader.ReadUInt32() != SignatureConstant)
{
return(false);
}
reader.ReadByte(); // VersionMadeBySpecification
header.VersionMadeByCompatibility = reader.ReadByte();
reader.ReadUInt16(); // VersionNeededToExtract
header.GeneralPurposeBitFlag = reader.ReadUInt16();
header.CompressionMethod = reader.ReadUInt16();
header.LastModified = reader.ReadUInt32();
reader.ReadUInt32(); // Crc32
uint compressedSizeSmall = reader.ReadUInt32();
uint uncompressedSizeSmall = reader.ReadUInt32();
header.FilenameLength = reader.ReadUInt16();
header.ExtraFieldLength = reader.ReadUInt16();
header.FileCommentLength = reader.ReadUInt16();
ushort diskNumberStartSmall = reader.ReadUInt16();
reader.ReadUInt16(); // InternalFileAttributes
reader.ReadUInt32(); // ExternalFileAttributes
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))
{
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.
// Fen's note: Original did a seek here, which for some reason is like 300x slower than a read, and
// also inexplicably causes ReadUInt32() to be 4x as slow and/or occur 4x as often(?!)
// Buffer alignments...? I dunno. Anyway. Speed.
// Also maybe not a good idea to use something that's faster when I don't know why it's faster.
// But my results are the same as the old method, so herpaderp.
reader.BaseStream.AdvanceToPosition(endExtraFields + header.FileCommentLength);
header.UncompressedSize = zip64.UncompressedSize ?? uncompressedSizeSmall;
header.CompressedSize = zip64.CompressedSize ?? compressedSizeSmall;
header.RelativeOffsetOfLocalHeader = zip64.LocalHeaderOffset ?? relativeOffsetOfLocalHeaderSmall;
header.DiskNumberStart = zip64.StartDiskNumber ?? diskNumberStartSmall;
return(true);
}
