private void Init(Stream stream)
{
_stream = stream;
_header = new Header();
_decoder = new BinaryDecoder(stream);
_syncBuffer = new byte[DataFileConstants.SyncSize];
// validate header
byte[] firstBytes = new byte[DataFileConstants.AvroHeader.Length];
try
{
_decoder.ReadFixed(firstBytes);
}
catch (Exception)
{
throw new InvalidAvroHeaderException();
}
if (!firstBytes.SequenceEqual(DataFileConstants.AvroHeader))
{
throw new InvalidAvroHeaderException();
}
// read meta data
long len = _decoder.ReadMapStart();
if (len > 0)
{
do
{
for (long i = 0; i < len; i++)
{
string key = _decoder.ReadString();
byte[] val = _decoder.ReadBytes();
_header.MetaData.Add(key, val);
}
} while ((len = _decoder.ReadMapNext()) != 0);
}
// read in sync data
_decoder.ReadFixed(_header.SyncData);
// parse schema and set codec
_header.Schema = Schema.Parse(GetMetaString(DataFileConstants.SchemaMetadataKey));
_reader = _datumReaderFactory(_header.Schema, _readerSchema ?? _header.Schema);
_codec = ResolveCodec();
}
private Codec ResolveCodec()
{
return(Codec.CreateCodecFromString(GetMetaString(DataFileConstants.CodecMetadataKey)));
}