public GMAHeader ReadHeader()
{
BaseStream.Seek(0, SeekOrigin.Begin);
// Magic constant "GMAD"
byte[] magicConstant = ReadBytes(4);
if (Encoding.ASCII.GetString(magicConstant) != "GMAD")
{
throw new Exception("Invalid file type");
}
byte gmaVersion = ReadByte();
if (gmaVersion > 3)
{
throw new Exception("Unsupported GMA version " + gmaVersion);
}
GMAHeader header = new GMAHeader
{
SteamID = ReadUInt64(),
Timestamp = ReadInt64(),
RequiredContent = ReadNullTerminatedString(),
Name = ReadNullTerminatedString(),
Description = ReadNullTerminatedString(),
Author = ReadNullTerminatedString(),
Version = ReadInt32()
};
List <GMAFileHeader> files = new List <GMAFileHeader>();
long curOffset = 0;
while (ReadUInt32() > 0)
{
GMAFileHeader curFile = new GMAFileHeader
{
Path = ReadNullTerminatedString(),
Size = ReadInt64(),
CRC = ReadUInt32(),
FileNumber = files.Count,
Offset = curOffset
};
curOffset += curFile.Size;
files.Add(curFile);
}
header.DataStart = BaseStream.Position;
header.Files = files.ToArray();
return(header);
}
public byte[] GetFileData(int fileNumber)
{
if (_fileDataCache.ContainsKey(fileNumber))
{
return(_fileDataCache[fileNumber]);
}
GMAFileHeader file = Files.Single(f => f.FileNumber == fileNumber);
_reader.BaseStream.Seek(_header.DataStart + file.Offset, SeekOrigin.Begin);
byte[] data = _reader.ReadBytes((int)file.Size);
uint computedCRC = CRC32(data);
if (file.CRC != computedCRC)
{
throw new CRCMismatchException($"CRC mismatch for {file.Path}");
}
_fileDataCache[fileNumber] = data;
return(data);
}
public GMAFileHeader[] GetModelFiles(GMAFileHeader model)
{
string path = model.Path.Substring(0, model.Path.Length - 4);
return(Files.Where(f => f.Path.StartsWith(path, StringComparison.InvariantCultureIgnoreCase)).ToArray());
}
