The device descriptors are extended with a filter function. During the
device discovery, this filter function is used to return only devices
that match a known dive computer.
The filtering is optional, and can be disabled by passing a NULL pointer
for the device descriptor when creating the iterator with one of the
dc_xxx_iterator_new() functions.
Replacing the callback based interface with an iterator based interface,
results in a more extensible abstraction with a common interface for
each of the built-in I/O implementations (serial, usbhid, irda and
bluetooth).
When the port number is set to zero (which is an invalid value), detect
the port number automatically. On Windows, we can simply supply the UUID
of the serial port service, and the Windows api will take care of the
discovery. On Linux (bluez), the SDP discovery needs to be performed
manually to retrieve the port number.
For the socket based I/O stream implementations (IrDA and bluetooth) the
serial communication specific functions are meaningless. Implementing
them as no-ops allows the dive computer backends the call the I/O stream
functions unconditionally.
This is important for the bluetooth implementation, because bluetooth
enabled dive computers will be able to use both the native bluetooth
communication and the legacy bluetooth serial port emulation.
For the time being, the bluetooth communication code is of very limited
use. It's not used anywhere in the library, and as an internal api it's
also not available to applications. It serves mainly as a reference
implementation for future use.
The implementation supports Windows and Linux.
