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333 lines
9.3 KiB
333 lines
9.3 KiB
# 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 nonoverlapping ranges on the |
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integers (ie, a set of integers, but efficient when the set contains |
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lots of runs.""" |
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def __init__(self, data=None): |
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self.monotonic = False |
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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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@classmethod |
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def parse(cls, text): |
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"""Parse a text string consisting of a space-separated list of |
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blocks and ranges, eg "10-20 30 35-40". Ranges are interpreted to |
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include both their ends (so the above example represents 18 |
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individual blocks. Returns a RangeSet object. |
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If the input has all its blocks in increasing order, then returned |
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RangeSet will have an extra attribute 'monotonic' that is set to |
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True. For example the input "10-20 30" is monotonic, but the input |
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"15-20 30 10-14" is not, even though they represent the same set |
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of blocks (and the two RangeSets will 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(rangelib.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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