def _update_features(self, char_handle, data, notify_update=False):
"""Update the features related to a given characteristic.
Args:
char_handle (int): The characteristic's handle to look for.
data (str): The data read from the given characteristic.
notify_update (bool, optional): If True all the registered listeners
are notified about the new data.
Returns:
bool: True if the characteristic has some features associated to it
and they have been updated, False otherwise.
"""
# Getting the features corresponding to the given characteristic.
features = self._get_corresponding_features(char_handle)
if features is None:
return False
# Computing the timestamp.
timestamp = self._unwrap_timestamp.unwrap(
LittleEndian.bytesToUInt16(data))
# Updating the features.
offset = TIMESTAMP_OFFSET_BYTES # Timestamp's bytes.
for feature in features:
offset += feature.update(timestamp, data, offset, notify_update)
return True
def extract_data(self, timestamp, data, offset):
"""Extract the data from the feature's raw data.
Args:
timestamp (int): Data's timestamp.
data (str): The data read from the feature.
offset (int): Offset where to start reading data.
Returns:
:class:`blue_st_sdk.feature.ExtractedData`: Container of the number
of bytes read and the extracted data.
Raises:
:exc:`Exception` if the data array has not enough data to read.
"""
if len(data) - offset < self.DATA_LENGTH_BYTES:
raise Exception('There are no %d bytes available to read.' \
% (self.DATA_LENGTH_BYTES))
sample = None
value = LittleEndian.bytesToUInt16(data, offset)
if self._is_low_range_sensor(value):
sample = self._get_low_range_sample(timestamp, value)
else:
sample = self._get_high_range_sample(timestamp, value)
return ExtractedData(sample, self.DATA_LENGTH_BYTES)
def extract_data(self, timestamp, data, offset):
"""Extract the data from the feature's raw data.
In this case it reads a 16-bit signed integer value.
Args:
timestamp (int): Data's timestamp.
data (str): The data read from the feature.
offset (int): Offset where to start reading data.
Returns:
:class:`blue_st_sdk.feature.ExtractedData`: Container of the number
of bytes read and the extracted data.
Raises:
:exc:`Exception` if the data array has not enough data to read.
"""
if (len(data) - offset < self.DATA_LENGTH_BYTES):
raise Exception('There are no %d bytes available to read.' %
(self.DATA_LENGTH_BYTES))
offset = offset
flags = data[offset]
offset += 1
if self.has8BitHeartRate(flags):
hr = data[offset]
offset += 1
else:
hr = LittleEndian.bytesToUInt16(data, offset)
offset += 2
if self.hasEnergyExpended(flags):
ee = LittleEndian.bytesToUInt16(data, offset)
offset += 2
else:
ee = -1
if self.hasRRInterval(flags):
rri = LittleEndian.bytesToUInt16(data, offset) / 1024.0
offset += 2
else:
rri = float('nan')
return ExtractedData(
Sample(timestamp, [hr, ee, rri], getFieldsDescription()),
offset - offset)