string DecryptName(byte[] name_buf, int name_length, TpRandom key)
{
for (int i = 0; i < name_length; ++i)
{
name_buf[i] ^= (byte)key.GetRand32();
}
return(Encodings.cp932.GetString(name_buf, 0, name_length));
}
static IEnumerable <int> RandomSequence(int count, uint seed)
{
var tp = new TpRandom(seed);
var order = Enumerable.Range(0, count).ToList <int>();
for (int i = 0; i < count; ++i)
{
int n = (int)(tp.GetRand32() % (uint)order.Count);
yield return(order[n]);
order.RemoveAt(n);
}
}
List <Entry> ReadIndex(ArcView file, uint base_offset, int count)
{
uint index_offset = base_offset + 0xA;
var name_buffer = new byte[0x100];
var rnd = new TpRandom(0x75D6EE39u);
var dir = new List <Entry> (count);
for (int i = 0; i < count; ++i)
{
uint name_length = file.View.ReadUInt32(index_offset);
index_offset += 4;
if (0 == name_length || name_length > name_buffer.Length)
{
return(null);
}
if (name_length != file.View.Read(index_offset, name_buffer, 0, name_length))
{
return(null);
}
index_offset += name_length;
var name = DecryptName(name_buffer, (int)name_length, rnd);
dir.Add(Create <VfEntry> (name));
}
rnd.Reset();
long offset = base_offset + (file.View.ReadInt64(index_offset) ^ (int)rnd.GetRand32());
foreach (var entry in dir)
{
index_offset += 8;
long next_offset = base_offset + (file.View.ReadInt64(index_offset) ^ (int)rnd.GetRand32());
entry.Offset = offset;
entry.Size = (uint)(next_offset - offset);
offset = next_offset;
}
index_offset += 8;
foreach (VfEntry entry in dir)
{
byte flags = file.View.ReadByte(index_offset++);
entry.IsPacked = 0 == flags || 3 == flags;
entry.IsScrambled = 2 == flags || 3 == flags;
}
return(dir);
}