The new Excursion v6 firmware supports some new commands for accessing
the dive index, and also uses a completely new data format. To preserve
backwards compatibility in the download logic to some extent, some
critical fields such as the profile length, remain stored at identical
offsets.
The new data format now contains a version field to allow for future
modifications. This version field is located at byte offset 3, which
corresponds to the highest byte of the 32 bit dive number in the old
format. Thus, unless someone manages to reach 16M dives, this field will
always be zero for the old format.
Co-authored-by: Ryan Gardner <ryebrye@gmail.com>
When no dives are present, the maximum value for the progress events is
set to zero, which triggers an assert. Fixed by letting the progress
events reach 100% instead.
The memcpy and related functions expects a valid pointer, even if the
size is zero. Most libc implementations will handle a NULL pointer just
fine, but that's not guaranteed.
Simply skip the call when there is nothing to copy.
