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0cbc07227c
As required for further elaboration of uasyncio, like supporting baremetal systems with wraparound timesources. This is not intended to be public interface, and likely will be further refactored in the future.
95 lines
2.2 KiB
Python
95 lines
2.2 KiB
Python
# Test adhoc extension to uheapq to support wraparound
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# time (utime.ticks_ms() style) task queue.
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from utime import ticks_add, ticks_diff
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import uheapq as heapq
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DEBUG = 0
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MAX = ticks_add(0, -1)
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MODULO_HALF = MAX // 2 + 1
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if DEBUG:
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def dprint(*v):
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print(*v)
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else:
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def dprint(*v):
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pass
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# Try not to crash on invalid data
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h = []
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heapq.heappush(h, 1)
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try:
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heapq.heappush(h, 2, True)
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assert False
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except TypeError:
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pass
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heapq.heappush(h, 2)
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try:
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heapq.heappop(h, True)
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assert False
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except TypeError:
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pass
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def pop_all(h):
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l = []
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while h:
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l.append(heapq.heappop(h, True))
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dprint(l)
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return l
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def add(h, v):
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heapq.heappush(h, (v, None), True)
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h = []
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add(h, 0)
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add(h, MAX)
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add(h, MAX - 1)
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add(h, 101)
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add(h, 100)
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add(h, MAX - 2)
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dprint(h)
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l = pop_all(h)
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for i in range(len(l) - 1):
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diff = ticks_diff(l[i + 1][0], l[i][0])
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assert diff > 0
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def edge_case(edge, offset):
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h = []
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add(h, ticks_add(0, offset))
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add(h, ticks_add(edge, offset))
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dprint(h)
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l = pop_all(h)
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diff = ticks_diff(l[1][0], l[0][0])
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dprint(diff, diff > 0)
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return diff
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dprint("===")
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diff = edge_case(MODULO_HALF - 1, 0)
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assert diff == MODULO_HALF - 1
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assert edge_case(MODULO_HALF - 1, 100) == diff
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assert edge_case(MODULO_HALF - 1, -100) == diff
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# We expect diff to be always positive, per the definition of heappop() which should return
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# the smallest value.
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# This is the edge case where this invariant breaks, due to assymetry of two's-complement
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# range - there's one more negative integer than positive, so heappushing values like below
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# will then make ticks_diff() return the minimum negative value. We could make heappop
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# return them in a different order, but ticks_diff() result would be the same. Conclusion:
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# never add to a heap values where (a - b) == MODULO_HALF (and which are >= MODULO_HALF
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# ticks apart in real time of course).
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dprint("===")
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diff = edge_case(MODULO_HALF, 0)
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assert diff == -MODULO_HALF
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assert edge_case(MODULO_HALF, 100) == diff
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assert edge_case(MODULO_HALF, -100) == diff
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dprint("===")
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diff = edge_case(MODULO_HALF + 1, 0)
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assert diff == MODULO_HALF - 1
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assert edge_case(MODULO_HALF + 1, 100) == diff
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assert edge_case(MODULO_HALF + 1, -100) == diff
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print("OK")
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