Converting ParquetSharp.Int96 to System.DateTime

Question

I am using ParquetSharp to read a parquet file. One of the columns is typed as Int96. In reality it is a DateTime. I need to convert said ParquetSharp.Int96 to a System.DateTime.

Answer 1

I did this using the oddly named int A, int B, int C properties of the Int96 type. These Properties correspond to the 4 byte blocks that make up the int96.

using info found in here: Cast int96 timestamp from parquet to golang Int96Value to Date string

(there is some mention of magic numbers in these links.)

I was able to come up with this:

DateTime ConvertToDateTime(Int96 typed)
{
    var date = DateTime.FromOADate(typed.C - 2415018.5);
    var a = BitConverter.GetBytes(typed.A);
    var b = BitConverter.GetBytes(typed.B);

    var nano = a.Concat(b).ToArray();

    var nanoLong = BitConverter.ToInt64(nano, 0);

    var result = date.AddTicks(nanoLong / 100);
    return result;
}