/// <summary>
/// decompress an entire ME3 pcc file into a new stream
/// </summary>
/// <param name="input">pcc file passed in stream format</param>
/// <returns>a decompressed array of bytes</returns>
public static MemoryStream DecompressME3(Stream input)
{
input.Seek(0, SeekOrigin.Begin);
var magic = input.ReadValueU32(Endian.Little);
if (magic != 0x9E2A83C1 &&
magic.Swap() != 0x9E2A83C1)
{
throw new FormatException("not a pcc file");
}
var endian = magic == 0x9E2A83C1 ? Endian.Little : Endian.Big;
var versionLo = input.ReadValueU16(endian);
var versionHi = input.ReadValueU16(endian);
if (versionLo != 684 &&
versionHi != 194)
{
throw new FormatException("unsupported pcc version");
}
long headerSize = 8;
input.Seek(4, SeekOrigin.Current);
headerSize += 4;
var folderNameLength = input.ReadValueS32(endian);
headerSize += 4;
var folderNameByteLength =
folderNameLength >= 0 ? folderNameLength : (-folderNameLength * 2);
input.Seek(folderNameByteLength, SeekOrigin.Current);
headerSize += folderNameByteLength;
var packageFlagsOffset = input.Position;
var packageFlags = input.ReadValueU32(endian);
headerSize += 4;
if ((packageFlags & 0x02000000u) == 0)
{
throw new FormatException("pcc file is already decompressed");
}
if ((packageFlags & 8) != 0)
{
input.Seek(4, SeekOrigin.Current);
headerSize += 4;
}
uint nameCount = input.ReadValueU32(endian);
uint nameOffset = input.ReadValueU32(endian);
input.Seek(52, SeekOrigin.Current);
headerSize += 60;
var generationsCount = input.ReadValueU32(endian);
input.Seek(generationsCount * 12, SeekOrigin.Current);
headerSize += generationsCount * 12;
input.Seek(20, SeekOrigin.Current);
headerSize += 24;
var blockCount = input.ReadValueU32(endian);
int headBlockOff = (int)input.Position;
var afterBlockTableOffset = headBlockOff + (blockCount * 16);
var indataOffset = afterBlockTableOffset + 8;
byte[] buff;
input.Seek(0, SeekOrigin.Begin);
MemoryStream output = new MemoryStream();
output.Seek(0, SeekOrigin.Begin);
output.WriteFromStream(input, headerSize);
output.WriteValueU32(0, endian); // block count
input.Seek(afterBlockTableOffset, SeekOrigin.Begin);
output.WriteFromStream(input, 8);
//check if has extra name list (don't know it's usage...)
if ((packageFlags & 0x10000000) != 0)
{
long curPos = output.Position;
output.WriteFromStream(input, nameOffset - curPos);
}
//decompress blocks in parallel
Task <byte[]>[] tasks = new Task <byte[]> [blockCount];
uint[] uncompressedOffsets = new uint[blockCount];
for (int i = 0; i < blockCount; i++)
{
input.Seek(headBlockOff, SeekOrigin.Begin);
uncompressedOffsets[i] = input.ReadValueU32(endian);
var uncompressedSize = input.ReadValueU32(endian);
var compressedOffset = input.ReadValueU32(endian);
var compressedSize = input.ReadValueU32(endian);
headBlockOff = (int)input.Position;
buff = new byte[compressedSize];
input.Seek(compressedOffset, SeekOrigin.Begin);
input.Read(buff, 0, buff.Length);
tasks[i] = ZBlock.DecompressAsync(buff);
}
Task.WaitAll(tasks);
for (int i = 0; i < blockCount; i++)
{
output.Seek(uncompressedOffsets[i], SeekOrigin.Begin);
output.WriteBytes(tasks[i].Result);
}
output.Seek(packageFlagsOffset, SeekOrigin.Begin);
output.WriteValueU32(packageFlags & ~0x02000000u, endian);
return(output);
}
