#!/usr/bin/env python3

import os
import sys
import pyfits
import numpy



if __name__ == "__main__":

    mask_fn = sys.argv[1]
    out_fn = sys.argv[2]

    print("opening %s" % (mask_fn))
    h = pyfits.open(mask_fn)
    mask = h[0].data.astype(numpy.int32)

    print(mask.dtype)
    print("bitwise-and'ing")
    saturated = numpy.bitwise_and(mask, ( 2 | 256))

    print("Writing output to %s" % (out_fn))
    out_phdu = pyfits.PrimaryHDU(header=h[0].header, data=saturated)
    out_phdu.writeto(out_fn, clobber=True)

    print("all done!")