As a test, I loaded packet-ccsds.c:32026, which contains the original ccsds time-conversion code prior to outsourcing it to abs_time_to_str() and abs_time_to_str_secs(). The original code used 1-origin. Additionally, the packet-ccsds.c:32034 commit note states:
Add a third date format, ABSOLUTE_TIME_DOY_UTC, to show UTC with the
date as YYYY/DDD, where DDD is a 1-origin day of year.
So should have the code change in epan/to_str.c:32034 accounted for a 1-origin?
-Matthew
On 02/07/2011 22:21:19 +0100, Jaap Keuter wrote:
On 02/07/2011 07:46 PM, Guy Harris wrote:
On Feb 7, 2011, at 10:34 AM, Stephen Fisher wrote:
On Mon, Feb 07, 2011 at 07:52:30AM -0500, Matthew Parris wrote:
Within the abs_time_to_str function, 1900 is added to the tm_year
parameter, but 1 is not added to the tm_yday. I'm used to seeing
the day of the year equal to 1 on January 1st. Does anyone use 0
for January 1?
I agree that changing it to "1" for Jan 1 makes sense from a human
reading the screen perspective.
The "day of year" format code was introduced to support a couple of CCSDS:
http://en.wikipedia.org/wiki/Consultative_Committee_for_Space_Data_Systems
protocols. The code it replaced displayed the day-of-year as 0-origin; however, this document:
http://public.ccsds.org/publications/archive/301x0b2s.pdf
speaks of day-of-year as being 1-origin, at least for the ASCII time code formats.
Unless the NASA guys who contributed the packet-ccsds.c and packet-vcdu.c dissectors
would like to argue that, in their dissection, a 0-origin day-of-year works better,
in which case we should support both 0-origin and 1-origin display formats, I would
suggest switching to a 1-origin display format and see whether we get a complaint
from any space data people (in which case we should add a separate 0-origin format).
I say: Let's ask them!
Thanks,
Jaap
