The term "backend" can be confusing because it can refer to both the
virtual function table and the device/parser backends. The use of the
term "vtable" avoids this.
The hardcoded version strings are now grouped into arrays, according to
their corresponding layout descriptor. The main advantage of using
arrays is that new versions strings can now easily be added, without
having to modify any code.
I forgot to update the device and parser initialization functions to
store the context pointer into the objects. As a result, the internal
context pointers were always NULL.
Adding the "dc_" namespace prefix (which is of course an abbreviation
for libdivecomputer) should avoid conflicts with other libraries. For
the time being, only the high-level device and parser layers are
changed.
The logbook ringbuffer is now considered empty if any of the pointers is
outside the valid ringbuffer area. Compared to checking only against a
special empty value, this approach makes the code more robust against
invalid pointers.
Introducing a common base class allows to share more code between the
backends. Sharing the fingerprint data eliminates the need to pass it
with a function parameter.
The memory layout of all Oceanic devices is very similar, which allows
to share the parsing code between the different backends. Differences in
the layout are passed by means of a new layout descriptor structure.
Memory buffers are now allocated dynamically to support devices with
different amounts of memory.
