internal ZipReturn LocalFileHeaderRead(Stream zipFs)
{
try
{
using (BinaryReader br = new(zipFs, Encoding.UTF8, true))
{
SetStatus(LocalFileStatus.TrrntZip);
zipFs.Position = (long)RelativeOffsetOfLocalHeader;
uint thisSignature = br.ReadUInt32();
if (thisSignature != LocalFileHeaderSignature)
{
return(ZipReturn.ZipLocalFileHeaderError);
}
br.ReadUInt16(); // version needed to extract
ushort generalPurposeBitFlagLocal = br.ReadUInt16();
if (generalPurposeBitFlagLocal != GeneralPurposeBitFlag)
{
SetStatus(LocalFileStatus.TrrntZip, false);
}
ushort tshort = br.ReadUInt16();
if (tshort != _compressionMethod)
{
return(ZipReturn.ZipLocalFileHeaderError);
}
ushort lastModFileTime = br.ReadUInt16();
ushort lastModFileDate = br.ReadUInt16();
long tTime = CompressUtils.UtcTicksFromDosDateTime(lastModFileDate, lastModFileTime);
if (tTime != HeaderLastModified)
{
SetStatus(LocalFileStatus.DateTimeMisMatch);
SetStatus(LocalFileStatus.TrrntZip, false);
}
LocalFile localHeader = new();
localHeader.CRC = ReadCRC(br);
ulong localHeaderCompressedSize = br.ReadUInt32();
localHeader.UncompressedSize = br.ReadUInt32();
ulong localRelativeOffset = 0;
ushort fileNameLength = br.ReadUInt16();
ushort extraFieldLength = br.ReadUInt16();
byte[] bFileName = br.ReadBytes(fileNameLength);
localHeader.Filename = (generalPurposeBitFlagLocal & (1 << 11)) == 0
? CompressUtils.GetString(bFileName)
: Encoding.UTF8.GetString(bFileName, 0, fileNameLength);
if (extraFieldLength > 0)
{
byte[] extraField = br.ReadBytes(extraFieldLength);
ZipReturn zr = ZipExtraField.ReadExtraField(extraField, bFileName, localHeader, ref localHeaderCompressedSize, ref localRelativeOffset, false);
if (zr != ZipReturn.ZipGood)
{
return(zr);
}
}
if (!CompressUtils.CompareString(Filename, localHeader.Filename))
{
SetStatus(LocalFileStatus.TrrntZip, false);
if (!CompressUtils.CompareStringSlash(Filename.ToLower(), localHeader.Filename.ToLower()))
{
SetStatus(LocalFileStatus.FilenameMisMatch);
}
}
_dataLocation = (ulong)zipFs.Position;
if ((GeneralPurposeBitFlag & 8) == 8)
{
SetStatus(LocalFileStatus.TrrntZip, false);
zipFs.Position += (long)_compressedSize;
localHeader.CRC = ReadCRC(br);
if (CompressUtils.ByteArrCompare(localHeader.CRC, new byte[] { 0x08, 0x07, 0x4b, 0x50 }))
{
localHeader.CRC = ReadCRC(br);
}
if (GetStatus(LocalFileStatus.Zip64))
{
localHeaderCompressedSize = br.ReadUInt64();
localHeader.UncompressedSize = br.ReadUInt64();
}
else
{
localHeaderCompressedSize = br.ReadUInt32();
localHeader.UncompressedSize = br.ReadUInt32();
}
}
if (CompressUtils.IsCodePage437(Filename) != ((GeneralPurposeBitFlag & (1 << 11)) == 0))
{
SetStatus(LocalFileStatus.TrrntZip, false);
}
if (!CompressUtils.ByteArrCompare(localHeader.CRC, CRC))
{
return(ZipReturn.ZipLocalFileHeaderError);
}
if (localHeaderCompressedSize != _compressedSize)
{
return(ZipReturn.ZipLocalFileHeaderError);
}
if (localHeader.UncompressedSize != UncompressedSize)
{
return(ZipReturn.ZipLocalFileHeaderError);
}
return(ZipReturn.ZipGood);
}
}
catch
{
return(ZipReturn.ZipLocalFileHeaderError);
}
}