348 lines
9.5 KiB
Python
348 lines
9.5 KiB
Python
# Copyright (C) 2014 The Android Open Source Project
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from __future__ import print_function
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import heapq
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import itertools
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__all__ = ["RangeSet"]
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class RangeSet(object):
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"""A RangeSet represents a set of non-overlapping ranges on integers.
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Attributes:
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monotonic: Whether the input has all its integers in increasing order.
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extra: A dict that can be used by the caller, e.g. to store info that's
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only meaningful to caller.
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"""
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def __init__(self, data=None):
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self.monotonic = False
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self._extra = {}
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if isinstance(data, str):
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self._parse_internal(data)
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elif data:
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assert len(data) % 2 == 0
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self.data = tuple(self._remove_pairs(data))
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self.monotonic = all(x < y for x, y in zip(self.data, self.data[1:]))
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else:
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self.data = ()
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def __iter__(self):
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for i in range(0, len(self.data), 2):
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yield self.data[i:i+2]
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def __eq__(self, other):
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return self.data == other.data
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def __ne__(self, other):
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return self.data != other.data
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def __nonzero__(self):
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return bool(self.data)
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def __str__(self):
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if not self.data:
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return "empty"
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else:
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return self.to_string()
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def __repr__(self):
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return '<RangeSet("' + self.to_string() + '")>'
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@property
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def extra(self):
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return self._extra
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@classmethod
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def parse(cls, text):
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"""Parses a text string into a RangeSet.
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The input text string consists of a space-separated list of blocks and
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ranges, e.g. "10-20 30 35-40". Ranges are interpreted to include both their
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ends (so the above example represents 18 individual blocks). Returns a
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RangeSet object.
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If the input has all its blocks in increasing order, then the 'monotonic'
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attribute of the returned RangeSet will be set to True. For example the
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input "10-20 30" is monotonic, but the input "15-20 30 10-14" is not, even
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though they represent the same set of blocks (and the two RangeSets will
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compare equal with ==).
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"""
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return cls(text)
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@classmethod
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def parse_raw(cls, text):
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"""Parse a string generated by RangeSet.to_string_raw().
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>>> RangeSet.parse_raw(RangeSet("0-9").to_string_raw())
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<RangeSet("0-9")>
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"""
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raw = [int(i) for i in text.split(',')]
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assert raw[0] == len(raw[1:]), "Invalid raw string."
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return cls(data=raw[1:])
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def _parse_internal(self, text):
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data = []
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last = -1
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monotonic = True
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for p in text.split():
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if "-" in p:
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s, e = (int(x) for x in p.split("-"))
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data.append(s)
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data.append(e+1)
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if last <= s <= e:
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last = e
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else:
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monotonic = False
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else:
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s = int(p)
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data.append(s)
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data.append(s+1)
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if last <= s:
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last = s+1
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else:
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monotonic = False
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data.sort()
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self.data = tuple(self._remove_pairs(data))
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self.monotonic = monotonic
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@staticmethod
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def _remove_pairs(source):
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"""Remove consecutive duplicate items to simplify the result.
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[1, 2, 2, 5, 5, 10] will become [1, 10]."""
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last = None
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for i in source:
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if i == last:
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last = None
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else:
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if last is not None:
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yield last
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last = i
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if last is not None:
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yield last
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def to_string(self):
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out = []
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for i in range(0, len(self.data), 2):
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s, e = self.data[i:i+2]
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if e == s+1:
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out.append(str(s))
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else:
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out.append(str(s) + "-" + str(e-1))
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return " ".join(out)
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def to_string_raw(self):
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assert self.data
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return str(len(self.data)) + "," + ",".join(str(i) for i in self.data)
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def union(self, other):
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"""Return a new RangeSet representing the union of this RangeSet
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with the argument.
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>>> RangeSet("10-19 30-34").union(RangeSet("18-29"))
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<RangeSet("10-34")>
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>>> RangeSet("10-19 30-34").union(RangeSet("22 32"))
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<RangeSet("10-19 22 30-34")>
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"""
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out = []
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z = 0
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for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
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zip(other.data, itertools.cycle((+1, -1)))):
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if (z == 0 and d == 1) or (z == 1 and d == -1):
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out.append(p)
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z += d
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return RangeSet(data=out)
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def intersect(self, other):
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"""Return a new RangeSet representing the intersection of this
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RangeSet with the argument.
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>>> RangeSet("10-19 30-34").intersect(RangeSet("18-32"))
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<RangeSet("18-19 30-32")>
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>>> RangeSet("10-19 30-34").intersect(RangeSet("22-28"))
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<RangeSet("")>
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"""
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out = []
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z = 0
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for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
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zip(other.data, itertools.cycle((+1, -1)))):
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if (z == 1 and d == 1) or (z == 2 and d == -1):
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out.append(p)
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z += d
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return RangeSet(data=out)
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def subtract(self, other):
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"""Return a new RangeSet representing subtracting the argument
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from this RangeSet.
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>>> RangeSet("10-19 30-34").subtract(RangeSet("18-32"))
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<RangeSet("10-17 33-34")>
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>>> RangeSet("10-19 30-34").subtract(RangeSet("22-28"))
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<RangeSet("10-19 30-34")>
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"""
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out = []
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z = 0
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for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
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zip(other.data, itertools.cycle((-1, +1)))):
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if (z == 0 and d == 1) or (z == 1 and d == -1):
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out.append(p)
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z += d
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return RangeSet(data=out)
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def overlaps(self, other):
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"""Returns true if the argument has a nonempty overlap with this
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RangeSet.
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>>> RangeSet("10-19 30-34").overlaps(RangeSet("18-32"))
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True
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>>> RangeSet("10-19 30-34").overlaps(RangeSet("22-28"))
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False
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"""
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# This is like intersect, but we can stop as soon as we discover the
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# output is going to be nonempty.
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z = 0
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for _, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
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zip(other.data, itertools.cycle((+1, -1)))):
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if (z == 1 and d == 1) or (z == 2 and d == -1):
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return True
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z += d
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return False
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def size(self):
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"""Returns the total size of the RangeSet (ie, how many integers
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are in the set).
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>>> RangeSet("10-19 30-34").size()
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15
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"""
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total = 0
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for i, p in enumerate(self.data):
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if i % 2:
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total += p
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else:
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total -= p
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return total
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def map_within(self, other):
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"""'other' should be a subset of 'self'. Returns a RangeSet
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representing what 'other' would get translated to if the integers
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of 'self' were translated down to be contiguous starting at zero.
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>>> RangeSet("0-9").map_within(RangeSet("3-4"))
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<RangeSet("3-4")>
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>>> RangeSet("10-19").map_within(RangeSet("13-14"))
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<RangeSet("3-4")>
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>>> RangeSet("10-19 30-39").map_within(RangeSet("17-19 30-32"))
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<RangeSet("7-12")>
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>>> RangeSet("10-19 30-39").map_within(RangeSet("12-13 17-19 30-32"))
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<RangeSet("2-3 7-12")>
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"""
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out = []
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offset = 0
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start = None
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for p, d in heapq.merge(zip(self.data, itertools.cycle((-5, +5))),
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zip(other.data, itertools.cycle((-1, +1)))):
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if d == -5:
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start = p
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elif d == +5:
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offset += p-start
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start = None
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else:
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out.append(offset + p - start)
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return RangeSet(data=out)
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def extend(self, n):
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"""Extend the RangeSet by 'n' blocks.
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The lower bound is guaranteed to be non-negative.
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>>> RangeSet("0-9").extend(1)
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<RangeSet("0-10")>
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>>> RangeSet("10-19").extend(15)
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<RangeSet("0-34")>
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>>> RangeSet("10-19 30-39").extend(4)
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<RangeSet("6-23 26-43")>
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>>> RangeSet("10-19 30-39").extend(10)
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<RangeSet("0-49")>
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"""
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out = self
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for i in range(0, len(self.data), 2):
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s, e = self.data[i:i+2]
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s1 = max(0, s - n)
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e1 = e + n
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out = out.union(RangeSet(str(s1) + "-" + str(e1-1)))
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return out
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def first(self, n):
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"""Return the RangeSet that contains at most the first 'n' integers.
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>>> RangeSet("0-9").first(1)
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<RangeSet("0")>
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>>> RangeSet("10-19").first(5)
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<RangeSet("10-14")>
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>>> RangeSet("10-19").first(15)
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<RangeSet("10-19")>
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>>> RangeSet("10-19 30-39").first(3)
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<RangeSet("10-12")>
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>>> RangeSet("10-19 30-39").first(15)
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<RangeSet("10-19 30-34")>
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>>> RangeSet("10-19 30-39").first(30)
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<RangeSet("10-19 30-39")>
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>>> RangeSet("0-9").first(0)
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<RangeSet("")>
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"""
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if self.size() <= n:
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return self
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out = []
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for s, e in self:
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if e - s >= n:
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out += (s, s+n)
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break
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else:
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out += (s, e)
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n -= e - s
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return RangeSet(data=out)
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def next_item(self):
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"""Return the next integer represented by the RangeSet.
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>>> list(RangeSet("0-9").next_item())
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[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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>>> list(RangeSet("10-19 3-5").next_item())
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[3, 4, 5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
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>>> list(RangeSet("10-19 3 5 7").next_item())
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[3, 5, 7, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
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"""
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for s, e in self:
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for element in range(s, e):
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yield element
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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