internal GrpMetaData UnpackHeader(CowArray <byte> header)
{
uint width = header.ToUInt32(0);
uint height = header.ToUInt32(4);
int bpp = header.ToInt32(8);
int packed_size = header.ToInt32(0x0C);
int unpacked_size = header.ToInt32(0x10);
if (0 == width || 0 == height || width > 0x7fff || height > 0x7fff ||
(bpp != 24 && bpp != 8) ||
unpacked_size <= 0 || packed_size < 0)
{
return(null);
}
return(new GrpMetaData
{
Width = width,
Height = height,
BPP = bpp,
PackedSize = packed_size,
UnpackedSize = unpacked_size,
Offset = header.ToInt32(0x14),
HeaderSize = 0x18,
AlphaChannel = false,
});
}
byte[] QueryKey(string arc_name)
{
if (VFS.IsVirtual)
{
return(null);
}
var dir = VFS.GetDirectoryName(arc_name);
var parent_dir = Directory.GetParent(dir).FullName;
var exe_files = VFS.GetFiles(VFS.CombinePath(parent_dir, "*.exe")).Concat(VFS.GetFiles(VFS.CombinePath(dir, "*.exe")));
foreach (var exe_entry in exe_files)
{
try
{
using (var exe = new ExeFile.ResourceAccessor(exe_entry.Name))
{
var code = exe.GetResource("CIPHERCODE", "CODE");
if (null == code)
{
continue;
}
if (20 == code.Length)
{
code = new CowArray <byte> (code, 4, 16).ToArray();
}
return(code);
}
}
catch { /* ignore errors */ }
}
return(null);
}
public override ArcFile TryOpen(ArcView file)
{
if (null == KnownSchemes)
{
throw new OperationCanceledException("Outdated encryption schemes database");
}
var cpz = CpzHeader.Parse(file);
if (null == cpz)
{
return(null);
}
var index = file.View.ReadBytes(cpz.IndexOffset, cpz.IndexSize);
if (!cpz.VerifyIndex(index))
{
return(null);
}
int file_table_size = cpz.DirEntriesSize + cpz.FileEntriesSize;
if (cpz.IndexKeySize > 24)
{
var index_key = UnpackIndexKey(index, file_table_size, cpz.IndexKeySize);
for (int i = 0; i < file_table_size; ++i)
{
index[i] ^= index_key[(i + 3) % 0x3FF];
}
}
ArchiveKey arc_key = null;
if (cpz.Version > 6)
{
arc_key = FindArchiveKey(file.Name);
}
if (null == arc_key)
{
arc_key = new ArchiveKey();
}
var index_copy = new CowArray <byte> (index, 0, file_table_size).ToArray();
var cmvs_md5 = cpz.CmvsMd5.Clone() as uint[];
foreach (var scheme in KnownSchemes.Values.Where(s => s.Version == cpz.Version))
{
var arc = ReadIndex(file, scheme, cpz, index, arc_key);
if (null != arc)
{
return(arc);
}
// both CmvsMd5 and index was altered by ReadIndex in decryption attempt
Array.Copy(cmvs_md5, cpz.CmvsMd5, 4);
Array.Copy(index, index_copy, file_table_size);
}
throw new UnknownEncryptionScheme();
}
static unsafe void DecryptData(byte[] data, int pos, int length, uint key, uint seed)
{
if (pos < 0 || pos + length > data.Length)
{
throw new ArgumentOutOfRangeException("pos", "Invalid byte array index.");
fixed(byte *data8 = &data[pos])
{
uint *data32 = (uint *)data8;
for (int count = length / 4; count > 0; --count)
{
*data32 ^= key;
key += Binary.RotL(*data32, 16) ^ seed;
data32++;
}
}
}
RepiEntry EntryFromMd5(byte[] data, int pos, StringBuilder builder)
{
var key = new CowArray <byte> (data, pos, 16).ToArray();
string name;
if (KnownNames.TryGetValue(key, out name))
{
var entry = FormatCatalog.Instance.Create <RepiEntry> (name);
entry.HasEncryptionKey = true;
return(entry);
}
builder.Clear();
for (int i = 0; i < 16; ++i)
{
builder.AppendFormat("{0:x2}", key[i]);
}
return(new RepiEntry {
Name = builder.ToString()
});
}
