77 lines
2.4 KiB
Python
77 lines
2.4 KiB
Python
# This file is part of Hypothesis, which may be found at
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# https://github.com/HypothesisWorks/hypothesis/
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#
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# Most of this work is copyright (C) 2013-2021 David R. MacIver
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# (david@drmaciver.com), but it contains contributions by others. See
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# CONTRIBUTING.rst for a full list of people who may hold copyright, and
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# consult the git log if you need to determine who owns an individual
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# contribution.
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#
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# This Source Code Form is subject to the terms of the Mozilla Public License,
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# v. 2.0. If a copy of the MPL was not distributed with this file, You can
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# obtain one at https://mozilla.org/MPL/2.0/.
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#
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# END HEADER
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class IntervalSet:
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def __init__(self, intervals):
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self.intervals = tuple(intervals)
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self.offsets = [0]
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for u, v in self.intervals:
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self.offsets.append(self.offsets[-1] + v - u + 1)
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self.size = self.offsets.pop()
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def __len__(self):
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return self.size
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def __iter__(self):
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for u, v in self.intervals:
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yield from range(u, v + 1)
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def __getitem__(self, i):
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if i < 0:
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i = self.size + i
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if i < 0 or i >= self.size:
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raise IndexError(f"Invalid index {i} for [0, {self.size})")
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# Want j = maximal such that offsets[j] <= i
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j = len(self.intervals) - 1
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if self.offsets[j] > i:
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hi = j
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lo = 0
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# Invariant: offsets[lo] <= i < offsets[hi]
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while lo + 1 < hi:
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mid = (lo + hi) // 2
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if self.offsets[mid] <= i:
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lo = mid
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else:
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hi = mid
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j = lo
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t = i - self.offsets[j]
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u, v = self.intervals[j]
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r = u + t
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assert r <= v
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return r
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def __repr__(self):
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return f"IntervalSet({self.intervals!r})"
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def index(self, value):
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for offset, (u, v) in zip(self.offsets, self.intervals):
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if u == value:
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return offset
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elif u > value:
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raise ValueError(f"{value} is not in list")
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if value <= v:
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return offset + (value - u)
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raise ValueError(f"{value} is not in list")
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def index_above(self, value):
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for offset, (u, v) in zip(self.offsets, self.intervals):
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if u >= value:
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return offset
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if value <= v:
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return offset + (value - u)
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return self.size
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