Introduce StructArray that can be used for repeated register #10
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structures. This is better than a tuple of objects because it creates fewer objects by default and is a fixed cost per device independent of the number of entries in the array.
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I wonder how feasible would be using this for the displays. |
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its worth thinking about. I did something similar in the experimental is31fl3731 drivers here: https://github.com/adafruit/Adafruit_CircuitPython_IS31FL3731/blob/experimental/adafruit_is31fl3731.py#L132 It doesn't handle 2D slices as far as I know though. |
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Speaking of is31fl3731, I think we should make it use the framebuf module, once it's available in all ports. |
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| class _BoundStructArray: | ||
| """ | ||
| Actual array object that `StructArray` constructs on demand for |
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| def _header(self, index): | ||
| """Shared bounds checking and buffer creation.""" | ||
| if index < 0 or index >= self.count: |
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I would prefer if not 0 <= index < self.count: here.
| # We create the buffer every time instead of keeping the buffer (which is 32 bytes at least) | ||
| # around forever. | ||
| buf = bytearray(size + 1) | ||
| buf[0] = self.first_register + size * index |
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Not sure this is correct. Chips that have 16 or 32 bit registers don't usually address them with gaps. If the first_register is 40, then the second will be 41, even if the register is 16-bit.
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I added a note warning about this.
| self.obj = obj | ||
| self.count = count | ||
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| def _header(self, index): |
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Maybe this would be better called _get_buffer or something like that? _header doesn't really say much.
| self.format = struct_format | ||
| self.address = register_address | ||
| self.count = count | ||
| self.array_id = "_structarray" + str(register_address) |
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.format() would be more readable here.
| return getattr(obj, self.array_id) | ||
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| def __set__(self, obj, value): | ||
| raise RuntimeError() |
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I think you can simply not define this, and then the property will be read-only.
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Done. That makes it a non-data descriptor (according to this) but that should be ok.
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@deshipu please take another look! |
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@deshipu gaves the thumbs up over Discord. |
Updating https://github.com/adafruit/Adafruit_CircuitPython_PCA9685 to 3.1.0 from 3.0.0: > Merge pull request adafruit/Adafruit_CircuitPython_PCA9685#10 from tannewt/struct_array Updating https://github.com/adafruit/Adafruit_CircuitPython_Register to 1.2.0 from 1.1.0: > Merge pull request adafruit/Adafruit_CircuitPython_Register#9 from tannewt/struct_opt > Merge pull request adafruit/Adafruit_CircuitPython_Register#10 from tannewt/struct_array
structures. This is better than a tuple of objects because it
creates fewer objects by default and is a fixed cost per device
independent of the number of entries in the array.