kopia lustrzana https://github.com/peterhinch/micropython-nano-gui
73 wiersze
2.9 KiB
Python
73 wiersze
2.9 KiB
Python
# parse2d.py Parse args for item access dunder methods for a 2D array.
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# Released under the MIT License (MIT). See LICENSE.
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# Copyright (c) 2023 Peter Hinch
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# Called from __getitem__ or __setitem__ args is a 1-tuple. The single item may be an int or a
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# slice for 1D access. Or it may be a 2-tuple for 2D access. Items in the 2-tuple may be ints
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# or slices in any combination.
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# As a generator it returns offsets into the underlying 1D array or list.
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def do_args(args, nrows, ncols):
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# Given a slice and a maximum address return start and stop addresses (or None on error)
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# Step value must be 1, hence does not support start > stop (used with step < 0)
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def do_slice(sli, nbytes):
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step = sli.step if sli.step is not None else 1
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start = sli.start if sli.start is not None else 0
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stop = sli.stop if sli.stop is not None else nbytes
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start = min(start if start >= 0 else max(nbytes + start, 0), nbytes)
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stop = min(stop if stop >= 0 else max(nbytes + stop, 0), nbytes)
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ok = (start < stop and step > 0) or (start > stop and step < 0)
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return (start, stop, step) if ok else None # Caller should check
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def ivalid(n, nmax): # Validate an integer arg, handle -ve args
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n = n if n >= 0 else nmax + n
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if n < 0 or n > nmax - 1:
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raise IndexError("Index out of range")
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return n
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def fail(n):
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raise IndexError("Invalid index", n)
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ncells = nrows * ncols
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n = args[0]
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if isinstance(n, int): # Index into 1D array
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yield ivalid(n, ncells)
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elif isinstance(n, slice): # Slice of 1D array
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cells = do_slice(n, ncells)
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if cells is not None:
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for cell in range(*cells):
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yield cell
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elif isinstance(n, tuple) or isinstance(n, list): # list allows for old [[]] syntax
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if len(n) != 2:
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fail(n)
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row = n[0] # May be slice
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if isinstance(row, int):
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row = ivalid(row, nrows)
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col = n[1]
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if isinstance(col, int):
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col = ivalid(col, ncols)
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if isinstance(row, int) and isinstance(col, int):
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yield row * ncols + col
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elif isinstance(row, slice) and isinstance(col, int):
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rows = do_slice(row, nrows)
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if rows is not None:
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for row in range(*rows):
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yield row * ncols + col
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elif isinstance(row, int) and isinstance(col, slice):
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cols = do_slice(col, ncols)
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if cols is not None:
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for col in range(*cols):
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yield row * ncols + col
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elif isinstance(row, slice) and isinstance(col, slice):
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rows = do_slice(row, nrows)
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cols = do_slice(col, ncols)
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if cols is not None and rows is not None:
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for row in range(*rows):
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for col in range(*cols):
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yield row * ncols + col
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else:
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fail(n)
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else:
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fail(n)
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