/// <summary>
/// Reads data from parquet stream
/// </summary>
/// <typeparam name="TModel">Type of model</typeparam>
/// <param name="mapConfig">Mapping configuration</param>
/// <param name="fileStream">Parquet stream</param>
/// <returns>parsed data</returns>
public TModel[] Read <TModel>(MapperConfig <TModel> mapConfig, Stream fileStream)
where TModel : new()
{
using var parquetReader = new ParquetReader(fileStream);
var dataFields = parquetReader.Schema.GetDataFields();
long modelOffset = 0;
var resArr = CreateArray <TModel>(parquetReader.ThriftMetadata.Num_rows);
for (int i = 0; i < parquetReader.RowGroupCount; i++)
{
using var groupReader = parquetReader.OpenRowGroupReader(i);
var columns = dataFields.Where(w => mapConfig.Contains(w.Name)).Select(groupReader.ReadColumn).ToArray();
ReadColumns(mapConfig, resArr, columns, modelOffset);
// increment offset to read next rowGroup
modelOffset += groupReader.RowCount;
}
return(resArr);
}