def decode(self, event):
""" Decodes the event message to its status bits
:param event: The event to decode
"""
if event != self.__encoded:
raise ParameterException('Invalid decoded value')
def __delitem__(self, slave):
""" Wrapper used to access the slave context
:param slave: The slave context to remove
"""
if not self.single and (0xf7 >= slave >= 0x00):
del self.__slaves[slave]
else:
raise ParameterException('slave index out of range')
def __setitem__(self, slave, context):
""" Used to set a new slave context
:param slave: The slave context to set
:param context: The new context to set for this slave
"""
if self.single:
slave = Defaults.UnitId
if 0xf7 >= slave >= 0x00:
self.__slaves[slave] = context
else:
raise ParameterException('slave index out of range')
def __getitem__(self, slave):
""" Used to get access to a slave context
:param slave: The slave context to get
:returns: The requested slave context
"""
if self.single:
slave = Defaults.UnitId
if slave in self.__slaves:
return self.__slaves.get(slave)
else:
raise ParameterException(
'slave does not exist, or is out of range'
)
def from_coils(cls, coils, endian=Endian.Little):
""" Initialize a payload decoder with the result of
reading a collection of coils from a modbus device.
The coils are treated as a list of bit(boolean) values.
:param coils: The coil results to initialize with
:param endian: The endianess of the payload
:returns: An initialized PayloadDecoder
"""
if isinstance(coils, list):
payload = pack_bitstring(coils)
return cls(payload, endian)
raise ParameterException('Invalid collection of coils supplied')
def __implementation(method):
""" Returns the requested framer
:method: The serial framer to instantiate
:returns: The requested serial framer
"""
method = method.lower()
if method == 'ascii':
return ModbusAsciiFramer(ClientDecoder())
elif method == 'rtu':
return ModbusRtuFramer(ClientDecoder())
elif method == 'binary':
return ModbusBinaryFramer(ClientDecoder())
elif method == 'socket':
return ModbusSocketFramer(ClientDecoder())
raise ParameterException('Invalid framer method requested')
def from_registers(cls, registers, endian=Endian.Little):
""" Initialize a payload decoder with the result of
reading a collection of registers from a modbus device.
The registers are treated as a list of 2 byte values.
We have to do this because of how the data has already
been decoded by the rest of the library.
:param registers: The register results to initialize with
:param endian: The endianess of the payload
:returns: An initialized PayloadDecoder
"""
if isinstance(registers, list): # repack into flat binary
payload = b''.join(pack('>H', x) for x in registers)
return cls(payload, endian)
raise ParameterException('Invalid collection of registers supplied')
def __init__(self, values):
""" Initializes the datastore
Using the input values we create the default
datastore value and the starting address
:param values: Either a list or a dictionary of values
"""
if isinstance(values, dict):
self.values = values
elif isinstance(values, Iterable):
self.values = dict(enumerate(values))
else:
raise ParameterException(
'Values for datastore must be a list or dictionary')
self.default_value = self.values.values().__next__().__class__()
self.address = self.values.keys().__next__()