void WriteArray(Array array, Type elementType, PropertyWriter writer)
{
stream.Write(array.Length);
var size = array.Length * Marshal.SizeOf(elementType);
bool compress = size >= CompressionThreshold;
stream.Write(compress ? 1 : 0);
var sw = stream;
DeflateWithChecksum codec = null;
var compressLengthPos = stream.BaseStream.Position;
stream.Write(size); // Placeholder compressed length
var dataStart = stream.BaseStream.Position;
if (compress)
{
stream.Write(new byte[] { 0x58, 0x85 }, 0, 2); // Header bytes for DeflateStream settings
codec = new DeflateWithChecksum(stream.BaseStream, CompressionMode.Compress, true);
sw = new BinaryWriter(codec);
}
foreach (var obj in array)
{
writer(sw, obj);
}
if (compress)
{
codec.Close(); // This is important - otherwise bytes can be incorrect
var checksum = codec.Checksum;
byte[] bytes =
{
(byte)((checksum >> 24) & 0xFF),
(byte)((checksum >> 16) & 0xFF),
(byte)((checksum >> 8) & 0xFF),
(byte)(checksum & 0xFF),
};
stream.Write(bytes);
}
// Now we can write the compressed data length, since we know the size
if (compress)
{
var dataEnd = stream.BaseStream.Position;
stream.BaseStream.Position = compressLengthPos;
stream.Write((int)(dataEnd - dataStart));
stream.BaseStream.Position = dataEnd;
}
}
// Reads an array, decompressing it if required
private Array readArray(ReadPrimitive readPrimitive, Type arrayType)
{
var len = _stream.ReadInt32();
var encoding = _stream.ReadInt32();
var compressedLen = _stream.ReadInt32();
var ret = Array.CreateInstance(arrayType, len);
var s = _stream;
var endPos = _stream.BaseStream.Position + compressedLen;
if (encoding != 0)
{
if (_errorLevel >= ErrorLevel.Checked)
{
if (encoding != 1)
{
throw new FbxException(_stream.BaseStream.Position - 1,
"Invalid compression encoding (must be 0 or 1)");
}
var cmf = _stream.ReadByte();
if ((cmf & 0xF) != 8 || (cmf >> 4) > 7)
{
throw new FbxException(_stream.BaseStream.Position - 1,
"Invalid compression format " + cmf);
}
var flg = _stream.ReadByte();
if (_errorLevel >= ErrorLevel.Strict && ((cmf << 8) + flg) % 31 != 0)
{
throw new FbxException(_stream.BaseStream.Position - 1,
"Invalid compression FCHECK");
}
if ((flg & (1 << 5)) != 0)
{
throw new FbxException(_stream.BaseStream.Position - 1,
"Invalid compression flags; dictionary not supported");
}
}
else
{
_stream.BaseStream.Position += 2;
}
var codec = new DeflateWithChecksum(_stream.BaseStream, CompressionMode.Decompress);
s = new BinaryReader(codec);
}
try
{
for (int i = 0; i < len; i++)
{
ret.SetValue(readPrimitive(s), i);
}
}
catch (InvalidDataException)
{
throw new FbxException(_stream.BaseStream.Position - 1,
"Compressed data was malformed");
}
if (encoding != 0)
{
if (_errorLevel >= ErrorLevel.Checked)
{
_stream.BaseStream.Position = endPos - sizeof(int);
var checksumBytes = new byte[sizeof(int)];
_stream.BaseStream.Read(checksumBytes, 0, checksumBytes.Length);
int checksum = 0;
for (int i = 0; i < checksumBytes.Length; i++)
{
checksum = (checksum << 8) + checksumBytes[i];
}
if (checksum != ((DeflateWithChecksum)s.BaseStream).Checksum)
{
throw new FbxException(_stream.BaseStream.Position,
"Compressed data has invalid checksum");
}
}
else
{
_stream.BaseStream.Position = endPos;
}
}
return(ret);
}