95 lines
2.2 KiB
Python
95 lines
2.2 KiB
Python
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# 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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