The Oceanic and Aeris F11 have a configurable sample rate. The possible
sample intervals are 2, 1, 0.5 and 0.25 seconds. Since our smallest unit
of time is one second, we can't represent the last two, and the extra
samples will get dropped for now.
Both the allocation and initialization of the object data structure is
now moved to a single function. The corresponding deallocation function
is intended to free objects that have been allocated, but are not fully
initialized yet. The public cleanup function shouldn't be used in such
case, because it may try to release resources that haven't been
initialized yet.
Instead of freeing the object data structure in the backend specific
cleanup function, the memory is now freed automatically in the base
class function. This reduces the amount of boilerplate code in the
backends. Backends that don't allocate any additional resources, do no
longer require a cleanup function at all.
When the close function returns, all resources should be freed,
regardless of whether an error has occured or not. The error code is
purely informative.
However, in order to return the first error code, which is usually the
most interesting one, the current implementation is unnecessary
complicated. If an error occurs, there is no need to exit immediately.
Simply store the error code unless there is already a previous one, and
then continue.
The universal application works well, but is quite difficult to extend
with more functionality. Therefore a new and more modular application is
needed. The new dctool application will support multiple sub-commands,
to carry out specific actions. Extending the application will be as easy
as adding new commands.
To store the day (range 1 to 31) as a binary encoded value, only 5 bits
are required. The extra 6th bit is part of the year. The year is also
not BCD encoded. This happened to work by accident, because for a single
nibble, the current implementation of the bcd2dec() function returns the
binary value.
The new gasmix sample contains the index of the active gas mix.
This new sample is intended as a replacement for the existing gas change
events (SAMPLE_EVENT_GASCHANGE and SAMPLE_EVENT_GASCHANGE2). To maintain
backwards compatibility, the legacy events are marked as deprecated but
not removed yet.
In CC mode, only the diluents are stored in the header. The list with
the OC gas mixes, which are used for bailout, are not stored in the
header. In order to retrieve the bailout mixes too, we need to parse the
profile and add them to the manual gas mixes.
The protocol of the iX3M series is almost identical to the protocol of
the iDive series. The main difference is that the command bytes and the
size of the response packets have been changed. In order to be able to
communicate with the correct set of commands, the user needs to supply
the correct number now. To maintain backwards compatibility, a new
variant of the open function is added.
Apparantly Fedora applies a custom patch to glibc's tcsetattr()
function, which adds an extra check to verify the PARENB/CREAD/CSIZE
bits in the termios c_cflag field.
However, in commit 197b9f09421111e03588c94d55a72aa6ec624c63 we already
discovered that for pty's, some of the termios settings make no sense at
all, and therefore the Linux kernel always does:
tty->termios.c_cflag &= ~(CSIZE | PARENB);
tty->termios.c_cflag |= (CS8 | CREAD);
Thus, instead of ignoring such nonsense termios settings, the kernel
changes the termios structure to reflect what pty's actually do. The
consequence is that these settings will not stick, and cause the extra
check in the Fedora specific patch to fail.
To workaround this problem, we ignore the error when building
libdivecomputer with pty support enabled.
If the dive computer has not recorded any dives yet, the profile pointer
isn't valid and contains the default value 0xFFFFFFFF. There is no need
to return an error in this case.
In some rare cases, the initial gas mix contains the value 0xFF. This
value is obviously outside the expected range (1-5), and therefore
causes the parsing to fail. It's not really clear how this can happen.
As a workaround for the fatal error, we now ignore the invalid value and
simply proceed without a gas mix.
The dive computer records the raw absolute pressure. To convert this
pressure value into a depth, we need to divide by the salinity factor,
not multiply!
The GCC 5 compiler with -Wpedantic enabled generates warnings for the
non-standard predefined identifier __FUNCTION___. These warnings can be
avoided by using the C99 identifier __func__ instead.
The internal Uwatec tank id should be converted to the libdivecomputer
tank index. If there is no corresponding tank, the tank pressure samples
are dropped for the following reasons:
Some models appear to record an absolute tank pressure sample, even if
there is no pressure sensor attached to the corresponding tank. In this
case only the tank index changes. The sample value simply retains the
last pressure of the previous tank. Since we don't have any real
pressure data, dropping those samples is fine.
Dives are downloaded using bulk transfers with an 8K buffer. Normally
the 2 second timeout is more than sufficient, and the timeout should
never expire, unless there is some serious communcation problem. But
nevertheless, users are reporting timeouts for dives having a length
that is an exact multiple of the USB packet size (64 bytes). In that
case, libusb reports a timeout with an non-zero amount of bytes
received. Despite the timeout, the received data contains a complete
dive.
I suspect libusb is somehow unable to determine whether the transfer is
complete and therefore waits until the timeout expires. For transfers
that are not a multiple of the USB packet size, the end of the transfer
is indicated by the last incomplete packet. This is not the case if the
length is an exact multiple of the USB packet size. This problem is
usually solved by sending a zero-length packet. Maybe the USB stack of
the Cobalt is not sending such a zero-length packet?
Atomics will address the problem with a Coblat 2 firmware upgrade, that
will simply append two zero bytes if the length is a multiple of 64
bytes. As a workaround for older firmware versions, we ignore the
timeout and process all received data. This shouldn't have any
disadvantages. An incomplete dive, for example due to a real timeout,
will now be detected by means of the minimum length and/or the checksum.
