Signature Description
enum class io_format : unsigned char  {
    csv = 1,
    json = 2,
    hdf5 = 3,   // Not Implemented
    binary = 4, // Not Implemented
}; 
This specifies the I/O format for reading and writing to/from files, streams, etc.
Currently only CSV format is supported. The CSV format is as follows:
  • Any empty line or any line started with # will be ignored
  • A data line has the following format:
    <column name>:<number of data points>:<\<type\>>:data,data,…
    An example line would look like this:
    price:1001:<double>:23.456,24.56,…