public override ArcFile TryOpen(ArcView file)
{
if (!file.View.AsciiEqual(0, "EPK"))
{
return(null);
}
int flags = file.View.ReadByte(3);
if (0 == (flags & 2))
{
return(null);
}
var scheme = DefaultScheme;
uint arc_key = scheme.BaseKey.Key1;
uint index_key = scheme.BaseKey.Key2;
var arc_info = new EpkInfo
{
AlignedOffset = 0 != (flags & 1),
Flag1 = 0 != (flags & 2),
WholeCrypt = 0 != (flags & 4),
IsEncrypted = 0 != (flags & 8),
IndexEncrypted = 0 != (flags & 0xF0),
PackedEntries = true,
};
uint index_size = file.View.ReadUInt32(4);
if (arc_info.IndexEncrypted)
{
var base_name = Path.GetFileNameWithoutExtension(file.Name).ToUpperInvariant();
var name_bytes = Encodings.cp932.GetBytes(base_name);
int back = name_bytes.Length - 1;
for (int i = 0; i < name_bytes.Length; ++i)
{
arc_key ^= name_bytes[back - i];
index_key ^= name_bytes[i];
arc_key = Binary.RotR(arc_key, 8);
index_key = Binary.RotL(index_key, 8);
}
index_size ^= index_key;
}
arc_info.Key = arc_key;
if (arc_info.AlignedOffset)
{
index_size <<= 11;
}
if (!arc_info.IndexEncrypted || arc_info.AlignedOffset)
{
index_size -= 8;
}
if (index_size >= file.MaxOffset)
{
return(null);
}
var index = file.View.ReadBytes(8, index_size);
if (arc_info.IndexEncrypted)
{
scheme.DecryptIndex(index, index.Length, index_key);
}
var reader = new EpkIndexReader(arc_info);
var dir = reader.Read(index);
if (null == dir)
{
return(null);
}
if (arc_info.IndexEncrypted)
{
return(new LuciArchive(file, this, dir, scheme, arc_info));
}
else
{
return(new ArcFile(file, this, dir));
}
}
public EpkIndexReader(EpkInfo info)
{
m_info = info;
}
