a196255841
Currently the date/time parsing assumes the reference time (epoch) of
the device clock is unknown. Hence we retrieve the current time of the
device (devtime) and the host system (systime) during the download.
Since both timestamps represent the same instant in time, but with a
different reference time, we can calibrate the device clock as follows:
ticks = parser->systime - (parser->devtime - timestamp) / 2
But this produces wrong results once the device clock has been adjusted
manually. Adjusting the device clock will suddenly increase (or
decrease) the devtime, while the systime continues ticking forwards
normally. Hence all dives recorded before the time adjustment will get
an incorrect date/time value.
Fortunately all devices appear to use a fixed epoch (2000-01-01 00:00:00
UTC) and we can simply replace the calibration with a hardcoded value.
Reported-By: Linus Torvalds <torvalds@linux-foundation.org>
Overview ======== Libdivecomputer is a cross-platform and open source library for communication with dive computers from various manufacturers. The official web site is: http://www.libdivecomputer.org/ The sourceforge project page is: http://sourceforge.net/projects/libdivecomputer/ Installation ============ On UNIX-like systems (including Linux, Mac OS X, MinGW), use the autotools based build system. Run the following commands from the top directory (containing this file) to configure, build and install the library and utilities: $ ./configure $ make $ make install If you downloaded the libdivecomputer source code directly from the git source code repository, then you need to create the configure script as the first step: $ autoreconf --install To uninstall libdivecomputer again, run: $ make uninstall Support ======= Please send bug reports, feedback or questions to the mailing list: http://libdivecomputer.org/cgi-bin/mailman/listinfo/devel or contact me directly: jef@libdivecomputer.org License ======= Libdivecomputer is free software, released under the terms of the GNU Lesser General Public License (LGPL). You can find a copy of the license in the file COPYING.