public override ArcFile TryOpen(ArcView file)
{
uint flags = file.View.ReadUInt32(4);
if ((flags & 0x7FFFFFFF) != 0x10000)
{
return(null);
}
int count = file.View.ReadInt32(8);
if (!IsSaneCount(count))
{
return(null);
}
bool is_encrypted = (flags >> 31) != 0;
uint index_size = (uint)((count * 24 + 31) & -4096) + 0xFE0u;
uint names_size = file.View.ReadUInt32(12);
var arc_md5 = file.View.ReadBytes(0x10, 0x10);
var index = new byte[index_size + names_size];
CsafEncryption enc = null;
try
{
if (is_encrypted)
{
file.View.Read(0x20, index, 0, index_size);
enc = new CsafEncryption(DefaultKey, DefaultIV);
using (var decryptor = enc.CreateDecryptor(0))
using (var enc_names = file.CreateStream(0x20 + index_size, names_size))
using (var dec_names = new InputCryptoStream(enc_names, decryptor))
{
dec_names.Read(index, (int)index_size, (int)names_size);
}
}
else
{
file.View.Read(0x20, index, 0, index_size + names_size);
}
using (var md5 = MD5.Create())
{
var hash = md5.ComputeHash(index);
if (!hash.SequenceEqual(arc_md5))
{
return(null);
}
int index_pos = 0x10;
int name_pos = (int)index_size;
var dir = new List <Entry> (count);
for (int i = 0; i < count; ++i)
{
int j;
for (j = name_pos; j + 1 < index.Length; j += 2)
{
if (index[j] == 0 && index[j + 1] == 0)
{
break;
}
}
int name_length = j - name_pos;
var name = Encoding.Unicode.GetString(index, name_pos, name_length);
// hash = md5.ComputeHash (index, name_pos, name_length); // == [index_pos-0x10]
name_pos += name_length + 10;
var entry = Create <Entry> (name);
entry.Offset = (long)index.ToUInt32(index_pos) << 12;
entry.Size = index.ToUInt32(index_pos + 4);
index_pos += 0x18;
if (!entry.CheckPlacement(file.MaxOffset))
{
return(null);
}
dir.Add(entry);
}
if (!is_encrypted)
{
return(new ArcFile(file, this, dir));
}
var arc = new CsafArchive(file, this, dir, enc);
enc = null;
return(arc);
}
}
finally
{
if (enc != null)
{
enc.Dispose();
}
}
}
public CsafStream(CsafArchive arc)
{
m_length = arc.File.MaxOffset;
m_view = arc.File.CreateFrame();
m_encryption = arc.Encryption;
}
