iframe-proxy | Sunbelt Computer Software

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from __future__ import annotations
import logging
from collections.abc import Collection, Mapping
from typing import Union
from canopen import objectdictionary
from canopen.utils import pretty_index
logger = logging.getLogger(__name__)
class Variable:
    def __init__(self, od: objectdictionary.ODVariable):
        self.od = od
        #: Description of this variable from Object Dictionary, overridable
        self.name = od.name
        if isinstance(od.parent, (objectdictionary.ODRecord,
                                  objectdictionary.ODArray)):
            # Include the parent object's name for subentries
            self.name = od.parent.name + "." + od.name
        #: Holds a local, overridable copy of the Object Index
        self.index = od.index
        #: Holds a local, overridable copy of the Object Subindex
        self.subindex = od.subindex
    def __repr__(self) -> str:
        subindex = self.subindex if isinstance(self.od.parent,
            (objectdictionary.ODRecord, objectdictionary.ODArray)
        ) else None
        return f"<{type(self).__qualname__} {self.name!r} at {pretty_index(self.index, subindex)}>"
    def get_data(self) -> bytes:
        raise NotImplementedError("Variable is not readable")
    def set_data(self, data: bytes):
        raise NotImplementedError("Variable is not writable")
    @property
    def data(self) -> bytes:
        """Byte representation of the object as :class:`bytes`."""
        return self.get_data()
    @data.setter
    def data(self, data: bytes):
        self.set_data(data)
    @property
    def raw(self) -> Union[int, bool, float, str, bytes]:
        """Raw representation of the object.
        This table lists the translations between object dictionary data types
        and Python native data types.
        +---------------------------+----------------------------+
        | Data type                 | Python type                |
        +===========================+============================+
        | BOOLEAN                   | :class:`bool`              |
        +---------------------------+----------------------------+
        | UNSIGNEDxx                | :class:`int`               |
        +---------------------------+----------------------------+
        | INTEGERxx                 | :class:`int`               |
        +---------------------------+----------------------------+
        | REALxx                    | :class:`float`             |
        +---------------------------+----------------------------+
        | VISIBLE_STRING            | :class:`str`               |
        +---------------------------+----------------------------+
        | UNICODE_STRING            | :class:`str`               |
        +---------------------------+----------------------------+
        | OCTET_STRING              | :class:`bytes`             |
        +---------------------------+----------------------------+
        | DOMAIN                    | :class:`bytes`             |
        +---------------------------+----------------------------+
        Data types that this library does not handle yet must be read and
        written as :class:`bytes`.
        """
        value = self.od.decode_raw(self.data)
        text = f"Value of {self.name!r} ({pretty_index(self.index, self.subindex)}) is {value!r}"
        if (
            isinstance(value, int)
            and (desc := self.od.value_descriptions.get(value)) is not None
            text += f" ({desc})"
        logger.debug(text)
        return value
    @raw.setter
    def raw(self, value: Union[int, bool, float, str, bytes]):
        logger.debug("Writing %r (0x%04X:%02X) = %r",
                     self.name, self.index,
                     self.subindex, value)
        self.data = self.od.encode_raw(value)
    @property
    def phys(self) -> Union[int, bool, float, str, bytes]:
        """Physical value scaled with some factor (defaults to 1).
        On object dictionaries that support specifying a factor, this can be
        either a :class:`float` or an :class:`int`.
        Non integers will be passed as is.
        """
        value = self.od.decode_phys(self.raw)
        if self.od.unit:
            logger.debug("Physical value is %s %s", value, self.od.unit)
        return value
    @phys.setter
    def phys(self, value: Union[int, bool, float, str, bytes]):
        self.raw = self.od.encode_phys(value)
    @property
    def desc(self) -> str:
        """Convert to and from a description of the value as a string.
        :raises TypeError: If the received raw data was anything but an integer value.
        """
        raw_int = self.raw
        if not isinstance(raw_int, int):
            raise TypeError("Description of values only supported for integer objects")
        value = self.od.decode_desc(raw_int)
        logger.debug("Description is '%s'", value)
        return value
    @desc.setter
    def desc(self, desc: str):
        self.raw = self.od.encode_desc(desc)
    @property
    def bits(self) -> Bits:
        """Access bits using integers, slices, or bit descriptions."""
        return Bits(self)
    def read(self, fmt: str = "raw") -> Union[int, bool, float, str, bytes]:
        """Alternative way of reading using a function instead of attributes.
        May be useful for asynchronous reading.
        :param str fmt:
            How to return the value
             - 'raw'
             - 'phys'
             - 'desc'
        :returns:
            The value of the variable.
        :raises ValueError: For unsupported fmt values.
        """
        if fmt == "raw":
            return self.raw
        elif fmt == "phys":
            return self.phys
        elif fmt == "desc":
            return self.desc
        raise ValueError(f"Invalid format '{fmt}'")
    def write(
        self,
        value: Union[int, bool, float, str, bytes],
        fmt: str = "raw",
    ) -> None:
        """Alternative way of writing using a function instead of attributes.
        May be useful for asynchronous writing.
        :param str fmt:
            How to write the value
             - 'raw'
             - 'phys'
             - 'desc'
        :raises TypeError: If the "desc" format was specified with anything but a string value.
        """
        if fmt == "raw":
            self.raw = value
        elif fmt == "phys":
            self.phys = value
        elif fmt == "desc":
            if not isinstance(value, str):
                raise TypeError("fmt=desc requires a string value")
            self.desc = value
class Bits(Mapping):
    def __init__(self, variable: Variable):
        assert variable.od.data_type in objectdictionary.datatypes.INTEGER_TYPES
        self.variable = variable
        self.read()
        self.raw: int
    @staticmethod
    def _get_bits(key: Union[slice, int, str, Collection[int]]) -> Union[str, Collection[int]]:
        if isinstance(key, slice):
            if key.stop is None:
                raise IndexError("Bits cannot be enumerated from open-ended slice")
            else:
                return range(key.start or 0, key.stop, key.step or 1)
        if isinstance(key, int):
            return [key]
        return key
    def __getitem__(self, key: Union[slice, int, str, Collection[int]]) -> int:
        return self.variable.od.decode_bits(self.raw, self._get_bits(key))
    def __setitem__(self, key: Union[slice, int, str, Collection[int]], value: int):
        self.raw = self.variable.od.encode_bits(
            self.raw, self._get_bits(key), value)
        self.write()
    def __iter__(self):
        return iter(self.variable.od.bit_definitions)
    def __len__(self):
        return len(self.variable.od.bit_definitions)
    def read(self):
        assert isinstance(raw_int := self.variable.raw, int)
        self.raw = raw_int
    def write(self):
        self.variable.raw = self.raw
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