The memory buffer already supported appending and prepending data, but
not inserting data anywhere in the buffer. That's exactly what the new
function does. The free space is still maintained at either the start or
the end of the buffer.
The USB communication is now also implemented as an I/O stream
transport. Unlike most I/O devices, USB communication supports multiple
interfaces and endpoints. This requires some some special care:
In the general case, autodetection isn't really possible without
additional knowledge. Hence the need for the filter parameters to pass
this kind of information.
The implementation assumes two bulk endpoints for the standard
read/write interface. Communication with the control endpoint is
supported through the new DC_IOCTL_USB_CONTROL_{READ,WRITE} ioctl's.
The set_latency function is the perfect example of a feature that should
be implemented as an ioctl: it's only implemented by a single driver,
and the functionality is also highly platform specific.
This new ioctl function allows to perform I/O stream specific requests
through a generic interface. This provides an easy way to extend the I/O
interface with some driver specific features, without having to modify
the public api.
The Linux implementation is very straighforward and just a lightweight
wrapper around the select function. But the Windows implementation is
much more complex, because the Windows event notification mechanism
behaves very different:
The WaitCommEvent function does not support a timeout and is always a
blocking call. The only way to implement a timeout is to use
asynchronous I/O (or overlapped I/O as it's called in the Windows API),
to run the operation in the background. This requires some additional
book keeping to keep track of the pending background operation.
The event mechanism is also edge triggered instead of level triggered,
and reading the event with the WaitCommEvent function clears the pending
event. Therefore, the state of the input buffer needs to be checked with
the ClearCommError function before and after the WaitCommEvent call.
The check before is necessary in case the event is already cleared by a
previous WaitCommEvent call, while there is still data present in the
input buffer. In this case, WaitCommEvent should not be called at all,
because it would wait until more data arrives.
The check afterwards is necessary in case WaitCommEvent reports a
pending event, while the data in the input buffer has already been
consumed. In this case, the current event must be ignored and
WaitCommEvent needs to be called again, to wait for the next event.
With the support for multiple transports per device, the
dc_descriptor_get_transport() function became obsolete because it does
support only a single transport type. Applications should use the new
dc_descriptor_get_transports() function instead.
Because the list of supported built-in transports depends on the
availability of external libraries (libusb, hidapi) and the operating
system, the application needs some mechanism to retrieve this
information at runtime. Therefore, a new dc_context_get_transports()
function is added, which returns a bitmask with all the available
built-in transports.
Several dive computers support multiple transports. For example the
Suunto Eon Steel supports both USB HID and BLE. All devices using
bluetooth classic communication support both the native bluetooth
transport and the legacy serial port emulation.
To support this feature, the values of the dc_transport_t type are
changed into bitmasks, and the dc_descriptor_t struct is extended with a
bitfield with all the supported transports.
Add a function to query the underlying transport type. This allows the
dive computer backends to implement transport specific behaviour where
necessary.
For the built-in I/O implementations, the transport type is obviously
always hardcoded, but for a custom I/O implementation the application
needs to provide the correct type. Hence the transport type can't be
hardcoded in the vtable and needs to be passed as a parameter.
The purpose of the new I/O interface is to provide a common interface
for all existing I/O implementations (serial, IrDA, bluetooth and USB
HID). With a common interface the dive computer backends can more easily
use different I/O implementations at runtime, without needing
significant code changes. For example bluetooth enabled devices can
easily switch between native bluetooth communication and serial port
emulation mode.
The new interface is modelled after the existing serial communication
api. Implementations where some of those functions are meaningless (e.g.
IrDA, bluetooth and USB), can just leave those functions unimplemented
(causing the call to fail with DC_STATUS_UNSUPPORTED), or implement it
as a no-op (always return DC_STATUS_SUCCESS).
Being able to synchronize the dive computer clock with the host system
is a very useful feature. Add the infrastructure to support this feature
through the public api.
The vendor_product_parser_create() and vendor_product_device_open()
functions should be called indirectly, through the generic
dc_device_open() and dc_parser_new() functions. And the
vendor_product_extract_dives() functions are internal functions that
should never have been part of the public api in the first place.
The current algorithm always downloads a full memory dump, and extracts
the dives afterwards. For the typical scenario where only a few dives
are being downloaded, this is inefficient because most of the data isn't
needed. This can easily be avoided by downloading the data on the fly.
The Cressi Drake is a mainly a freedive computer. The data format is
almost identical to the Leonardo. The main difference is that a single
dive now contains an entire freedive session. Each freedive in the
session is delimited with a 4 byte header containing the surface
interval and a special marker.
To be able to pass the OSTC 3 model number to the parser, and preserve
backwards compatibility, we need a new function. The new function should
also be used for the Frog, by passing zero as the model number.
Using the hw_ostc_parser_create() function with the hwos parameter set
to one, is now deprecated but will remain supported for backwards
compatibility.
For applications supporting offline parsing (like libdivecomputer's own
dctool application), some device specific knowledge is still required in
order to map a particular model to the corresponding backend. The new
convenience function will take care of that internally.
The already existing dc_parser_new() function does the same, but
requires an open device handle, which makes it unsuitable for offline
parsing.
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.
The latest firmware v1.75 introduced a new hardware descriptor byte to
identify the different models based on their hardware features. This new
hardware descriptor is now used as the libdivecomputer model number. For
older firmware versions, which do not support the descriptor yet, there
is an automatic fallback to the previous method based on the serial
number.
This change will be necessary for the Oceanic VTX, because it uses a
higher baudrate.
To maintain backwards compatibility, the existing function remains
unchanged and a new function is introduced instead.
This connects the bits and implements firmware upgrade for the OSTC3.
This code is inspired by JeanDo ostc-companion.
Reviewed-by: Jef Driesen <jef@libdivecomputer.org>
Signed-off-by: Anton Lundin <glance@acc.umu.se>
Basic Suunto EON Steel downloading copied from my test application.
This parses all the core dive data, including sample data (time, depth,
cylinder pressure, deco information etc).
The deco information returns ceiling and TTS rather than ceiling and
"time at ceiling", because that's what the dive computer has, and I
don't see any other way to return the information.
We don't report any events yet, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Starting with firmware v1.23, the OSTC3 settings can be configured
through the USB interface. There are new commands for reading, writing
and restoring the settings to their default values.
The Uwatec Meridian protocol is identical to the Uwatec Smart/Galileo
protocol, except for some additional framing around each data packet,
and the switch from IrDA to usb-serial communication. For parsing, the
data format appears to be identical to the Galileo data format.
Although the communication protocol of the OSTC3 is nearly identical to
that of the Frog, the different size parameters make it hard to share
the code easily. On top of that, if we ever implement native bluetooth
communication support, we'll need a completely separate backend anyway.
Therefore the Frog backend is simply duplicated, with a few OSTC3
specific changes applied here and there.
The existing ostc parser is upgraded to support the new OSTC3 data
format.
The Petrel (with updated firmware) supports an enhanced communication
protocol, which is more efficient and powerfull than the legacy Predator
compatibility mode. The new protocol uses data compression for faster
transfers and supports the ability to selectively download individual
dives. Last but not least, the new protocol isn't limited to the last
128kB of logbook data, but can access the full logbook capacity (16MB).
With the new interface, an application can easily retrieve the
underlying transport type from the device descriptors and present a
custom user interface element to the end-user for supplying transport
specific parameters. For example the serial port for devices using
serial communcication.
For devices using a usb-serial chipset or the bluetooth Serial Port
Profile (SPP/rfcomm), the transport type is DC_TRANSPORT_SERIAL, because
internally the serial emulation layer is used for the communication.
This is only a preliminary version. There is certainly some room for
improvement, but the basic functionality is already in place. That
should be sufficient for daily use, and possibles issues can always be
fixed when discovered.
The application shouldn't have to deal with the delay between packets.
If the default value isn't good enough, that should be fixed internally
and not on the application side.
The application shouldn't have to deal with the maximum number of
retries. If the default value isn't good enough, that should be fixed
internally and not on the application side.
The Uwatec Smart protocol supports reading individual settings. However
the version functions only reads those three values that we use
internally (model, serial number and device clock). That's a very
arbitrary subset and it would be much better to support reading
specific values. But that's something for later...
The version function requires device specific knowledge to use it (at
least the required buffer size), it is already called internally when
necessary, and only a few backends support it. Thus there is no good
reason to keep it in the high-level public api.
An application can now register an application defined callback
function, which will perform the actual logging. This provides
additional flexibility compared to logging to stderr with a hardcoded
format. Applications can now easily display the messages in their user
interface, customize the format, etc.
Although the internal logging function is a printf like function, the
arguments are converted into a plain string before being passed to the
callback function. This greatly improves interoperability with
programming languages which don't support C style variadic functions
(e.g. Python, C#, etc).
With the introduction of a context object, library initialization and
shutdown can be performed without requiring any global state. A single
process can use multiple independent contexts without any problems. The
lack of a global state also improves the thread-safety of the library.
At the moment, the new context object is primary used to implement an
improved logging system.
The devinfo and clock event data is now cached internally at the device layer.
This allows the new dc_parser_new() convenience function to retrieve the event
data directly from the device handle, and applications don't have to deal with
the events anymore to create a parser.
With the introduction of the device descriptors, the new dc_device_open()
convenience function can take care of the mapping from a particular model to
the corresponding backend internally, without needing any device specific
knowledge in the application. An application can simply query the list of
supported devices, and the library will automatically do the right thing.
Applications can now enumerate all the supported devices at runtime,
and don't have to maintain their own list anymore. The internal list
does include only those devices that have been confirmed to work at
least once without any major problems.
As the name already indicates, a device descriptor is lightweight
object which describes a single device. Currently, the api supports
getting the device name (vendor and product) and model number. But
this can extended with other features when necessary.
