private static void HandleDataBlock(byte[] data, int index, BLTEChunkInfo chunk, MemoryStream result)
{
switch (data[0])
{
case 0x4E: // N (no compression)
result.Write(data, 1, data.Length - 1);
break;
case 0x5A: // Z (zlib, compressed)
using (var stream = new MemoryStream(data, 3, chunk.compSize - 3))
using (var ds = new DeflateStream(stream, CompressionMode.Decompress))
{
ds.CopyTo(result);
}
break;
case 0x45: // E (encrypted)
byte[] decrypted = new byte[data.Length - 15];
decrypted[0] = 0x4E; // N
try
{
decrypted = Decrypt(data, index);
}
catch (KeyNotFoundException e)
{
Console.WriteLine(e.Message);
result.Write(new byte[chunk.decompSize], 0, chunk.decompSize);
break;
}
// Override inFileSize with decrypted length because it now differs from original encrypted chunk.compSize which breaks decompression
chunk.compSize = decrypted.Length;
HandleDataBlock(decrypted, index, chunk, result);
break;
case 0x46: // F (frame)
default:
throw new Exception("Unsupported mode " + data[0].ToString("X") + "!");
}
}
public static byte[] Parse(byte[] content)
{
using (var result = new MemoryStream())
using (var bin = new BinaryReader(new MemoryStream(content)))
{
if (bin.ReadUInt32() != 0x45544c42)
{
throw new Exception("Not a BLTE file");
}
var blteSize = bin.ReadUInt32(true);
BLTEChunkInfo[] chunkInfos;
if (blteSize == 0)
{
// These are always uncompressed
chunkInfos = new BLTEChunkInfo[1];
chunkInfos[0].isFullChunk = false;
chunkInfos[0].compSize = Convert.ToInt32(bin.BaseStream.Length - 8);
chunkInfos[0].decompSize = Convert.ToInt32(bin.BaseStream.Length - 8 - 1);
chunkInfos[0].checkSum = new byte[16];
}
else
{
var bytes = bin.ReadBytes(4);
var chunkCount = bytes[1] << 16 | bytes[2] << 8 | bytes[3] << 0;
var supposedHeaderSize = 24 * chunkCount + 12;
if (supposedHeaderSize != blteSize)
{
throw new Exception("Invalid header size!");
}
if (supposedHeaderSize > bin.BaseStream.Length)
{
throw new Exception("Not enough data");
}
chunkInfos = new BLTEChunkInfo[chunkCount];
for (int i = 0; i < chunkCount; i++)
{
chunkInfos[i].isFullChunk = true;
chunkInfos[i].compSize = bin.ReadInt32(true);
chunkInfos[i].decompSize = bin.ReadInt32(true);
chunkInfos[i].checkSum = new byte[16];
chunkInfos[i].checkSum = bin.ReadBytes(16);
}
}
for (var index = 0; index < chunkInfos.Count(); index++)
{
var chunk = chunkInfos[index];
if (chunk.compSize > (bin.BaseStream.Length - bin.BaseStream.Position))
{
throw new Exception("Trying to read more than is available!");
}
HandleDataBlock(bin.ReadBytes(chunk.compSize), index, chunk, result);
}
return(result.ToArray());
}
}
