geco_add_time_column

#!/usr/bin/env python
# (c) Stefan Countryman 2018

"""
Add a time column to a timeseries.
"""

import argparse
import sys

# DESC = """Read an input list of newline-delimited values from STDIN and write
# them to STDOUT as a CSV-formatted table where the 1st column is the time in
# GPS seconds (rounded down to the nearest integer), the 2nd column is the extra
# nanoseconds since the last integer second, and the 3rd column is the value of
# the input timeseries at that time.
# """

DESC = """Read an input list of newline-delimited values from STDIN and write
them to STDOUT as a CSV-formatted table where the 1st column is the time and
the 2nd column is the value of the input timeseries at that time.
"""


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description=DESC)
    parser.add_argument("-s", "--starttime", type=int,
                        help="The GPS time of the first datapoint.")
    parser.add_argument("-b", "--bitrate", type=int,
                        help="The bitrate in [Hz] of the timeseries.")
    args = parser.parse_args()
    ns_per_datapoint = 1e9 / args.bitrate
    for lineno, line in enumerate(sys.stdin):
        seconds = args.starttime + (lineno // args.bitrate)
        nanoseconds = int((lineno % args.bitrate) * ns_per_datapoint)
        sys.stdout.write('{}.{:09d}, {}'.format(seconds, nanoseconds, line))