Avoid plain malloc()/free() in sr/srd, especially in the API calls.
Also avoid g_malloc*() in favor of g_try_malloc*().
Use g_strdup() instead of strdup() so that we can use g_free()
consistently everywhere.
Exceptions: Stuff that is allocated via other libs (not using glib),
should also be properly free'd using the respective free-ing function
(instead of g_free()). Examples: Stuff allocated by libusb, libftdi, etc.
Also, use sr_err() instead of sr_warn() for actual errors. sr_warn() is
meant for non-fatal/uncritical warnings.
Use SR_API to mark public API symbols, and SR_PRIV for private symbols.
Variables and functions marked 'static' are private already and don't
need SR_PRIV. However, functions which are not static (because they need
to be used in other libsigrok-internal files) but are also not meant to
be part of the public libsigrok API, must use SR_PRIV.
This uses the 'visibility' feature of gcc (requires gcc >= 4.0).
Details: http://gcc.gnu.org/wiki/Visibility
They're not too useful as they mostly consist of a list of function names,
and that list is already available in the respective struct. The wiki
API docs and the code in the various hardware/output drivers serve as
useful examples already, no need for additional files.
The g_malloc()/g_malloc0() versions exit/segfault if not enough memory
is available, which is not a good thing in libsigrok.
Instead, we use the g_try_malloc()/g_try_malloc0() variants, which
return NULL if not enough memory is available, so that the caller can
handle the error properly.
Only output new lines in gnuplot output if there have been changes in
the samples (similar to what VCD does). As long as the first and last
sample are output, the resulting plot looks OK.
This reduces the size of the output file from roughly 200MB to just 60KB
in one specific test setup (depends on the number of probes and on the
signal, of course). The time and CPU load required to generate the gnuplot
output and the resulting plot (PNG or other) is also drastically reduced
from multiple minutes to roughly 30 seconds (again, depends on various
things).
Thanks Ken Mobley of ChronoVu for the report.
We should use these (internal) functions in libsigrok exclusively from
now on, i.e. no more use of glib's g_debug() etc.
These functions are only for libsigrok, the frontends use whatever
logging mechanism is suitable there.
The struct entry 'extension' is not really a (filename) extension, but
rather a unique ID used for input or output formats, e.g. in the sigrok
CLI or GUI interface. Thus, rename it accordingly.
Bert Vermeulen
Uwe Hermann