113 lines
3.8 KiB
Python
113 lines
3.8 KiB
Python
# The MIT License (MIT)
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#
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# Copyright (c) 2019 Dan Halbert for Adafruit Industries
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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"""
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`adafruit_bluefruit_connect.button_packet`
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====================================================
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Bluefruit Connect App Button data packet (button_name, pressed/released)
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* Author(s): Dan Halbert for Adafruit Industries
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"""
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import struct
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from .packet import Packet
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class ButtonPacket(Packet):
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"""A packet containing a button name and its state."""
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BUTTON_1 = "1"
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"""Code for Button 1 on the Bluefruit LE Connect app Control Pad screen."""
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BUTTON_2 = "2"
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"""Button 2."""
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BUTTON_3 = "3"
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"""Button 3."""
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BUTTON_4 = "4"
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"""Button 4."""
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# pylint: disable= invalid-name
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UP = "5"
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"""Up Button."""
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DOWN = "6"
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"""Down Button."""
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LEFT = "7"
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"""Left Button."""
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RIGHT = "8"
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"""Right Button."""
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_FMT_PARSE = "<xxssx"
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PACKET_LENGTH = struct.calcsize(_FMT_PARSE)
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# _FMT_CONSTRUCT doesn't include the trailing checksum byte.
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_FMT_CONSTRUCT = "<2sss"
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_TYPE_HEADER = b"!B"
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def __init__(self, button, pressed):
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"""Construct a ButtonPacket from a button name and the button's state.
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:param str button: a single character denoting the button
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:param bool pressed: ``True`` if button is pressed; ``False`` if it is release.
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"""
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# This check will catch wrong length and also non-sequence args (like an int).
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try:
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assert len(button) == 1
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except:
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raise ValueError("Button must be a single char or byte.")
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self._button = button
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self._pressed = pressed
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@classmethod
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def parse_private(cls, packet):
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"""Construct a ButtonPacket from an incoming packet.
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Do not call this directly; call Packet.from_bytes() instead.
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pylint makes it difficult to call this method _parse(), hence the name.
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"""
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button, pressed = struct.unpack(cls._FMT_PARSE, packet)
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if not pressed in b"01":
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raise ValueError("Bad button press/release value")
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return cls(chr(button[0]), pressed == b"1")
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def to_bytes(self):
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"""Return the bytes needed to send this packet."""
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partial_packet = struct.pack(
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self._FMT_CONSTRUCT,
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self._TYPE_HEADER,
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self._button,
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b"1" if self._pressed else b"0",
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)
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return self.add_checksum(partial_packet)
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@property
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def button(self):
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"""A single character string (not bytes) specifying the button."""
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return self._button
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@property
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def pressed(self):
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"""True if button is pressed."""
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return self._pressed
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# Register this class with the superclass. This allows the user to import only what is needed.
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ButtonPacket.register_packet_type()
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