# Copyright (C) 2014 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import print_function
import heapq
import itertools
__all__ = ["RangeSet"]
class RangeSet(object):
"""A RangeSet represents a set of nonoverlapping ranges on the
integers (ie, a set of integers, but efficient when the set contains
lots of runs."""
def __init__(self, data=None):
if isinstance(data, str):
self._parse_internal(data)
elif data:
self.data = tuple(self._remove_pairs(data))
else:
self.data = ()
def __iter__(self):
for i in range(0, len(self.data), 2):
yield self.data[i:i+2]
def __eq__(self, other):
return self.data == other.data
def __ne__(self, other):
return self.data != other.data
def __nonzero__(self):
return bool(self.data)
def __str__(self):
if not self.data:
return "empty"
else:
return self.to_string()
def __repr__(self):
return '<RangeSet("' + self.to_string() + '")>'
@classmethod
def parse(cls, text):
"""Parse a text string consisting of a space-separated list of
blocks and ranges, eg "10-20 30 35-40". Ranges are interpreted to
include both their ends (so the above example represents 18
individual blocks. Returns a RangeSet object.
If the input has all its blocks in increasing order, then returned
RangeSet will have an extra attribute 'monotonic' that is set to
True. For example the input "10-20 30" is monotonic, but the input
"15-20 30 10-14" is not, even though they represent the same set
of blocks (and the two RangeSets will compare equal with ==).
"""
return cls(text)
def _parse_internal(self, text):
data = []
last = -1
monotonic = True
for p in text.split():
if "-" in p:
s, e = p.split("-")
data.append(int(s))
data.append(int(e)+1)
if last <= s <= e:
last = e
else:
monotonic = False
else:
s = int(p)
data.append(s)
data.append(s+1)
if last <= s:
last = s+1
else:
monotonic = True
data.sort()
self.data = tuple(self._remove_pairs(data))
self.monotonic = monotonic
@staticmethod
def _remove_pairs(source):
last = None
for i in source:
if i == last:
last = None
else:
if last is not None:
yield last
last = i
if last is not None:
yield last
def to_string(self):
out = []
for i in range(0, len(self.data), 2):
s, e = self.data[i:i+2]
if e == s+1:
out.append(str(s))
else:
out.append(str(s) + "-" + str(e-1))
return " ".join(out)
def to_string_raw(self):
return str(len(self.data)) + "," + ",".join(str(i) for i in self.data)
def union(self, other):
"""Return a new RangeSet representing the union of this RangeSet
with the argument.
>>> RangeSet("10-19 30-34").union(RangeSet("18-29"))
<RangeSet("10-34")>
>>> RangeSet("10-19 30-34").union(RangeSet("22 32"))
<RangeSet("10-19 22 30-34")>
"""
out = []
z = 0
for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
zip(other.data, itertools.cycle((+1, -1)))):
if (z == 0 and d == 1) or (z == 1 and d == -1):
out.append(p)
z += d
return RangeSet(data=out)
def intersect(self, other):
"""Return a new RangeSet representing the intersection of this
RangeSet with the argument.
>>> RangeSet("10-19 30-34").intersect(RangeSet("18-32"))
<RangeSet("18-19 30-32")>
>>> RangeSet("10-19 30-34").intersect(RangeSet("22-28"))
<RangeSet("")>
"""
out = []
z = 0
for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
zip(other.data, itertools.cycle((+1, -1)))):
if (z == 1 and d == 1) or (z == 2 and d == -1):
out.append(p)
z += d
return RangeSet(data=out)
def subtract(self, other):
"""Return a new RangeSet representing subtracting the argument
from this RangeSet.
>>> RangeSet("10-19 30-34").subtract(RangeSet("18-32"))
<RangeSet("10-17 33-34")>
>>> RangeSet("10-19 30-34").subtract(RangeSet("22-28"))
<RangeSet("10-19 30-34")>
"""
out = []
z = 0
for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
zip(other.data, itertools.cycle((-1, +1)))):
if (z == 0 and d == 1) or (z == 1 and d == -1):
out.append(p)
z += d
return RangeSet(data=out)
def overlaps(self, other):
"""Returns true if the argument has a nonempty overlap with this
RangeSet.
>>> RangeSet("10-19 30-34").overlaps(RangeSet("18-32"))
True
>>> RangeSet("10-19 30-34").overlaps(RangeSet("22-28"))
False
"""
# This is like intersect, but we can stop as soon as we discover the
# output is going to be nonempty.
z = 0
for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))),
zip(other.data, itertools.cycle((+1, -1)))):
if (z == 1 and d == 1) or (z == 2 and d == -1):
return True
z += d
return False
def size(self):
"""Returns the total size of the RangeSet (ie, how many integers
are in the set).
>>> RangeSet("10-19 30-34").size()
15
"""
total = 0
for i, p in enumerate(self.data):
if i % 2:
total += p
else:
total -= p
return total
def map_within(self, other):
"""'other' should be a subset of 'self'. Returns a RangeSet
representing what 'other' would get translated to if the integers
of 'self' were translated down to be contiguous starting at zero.
>>> RangeSet("0-9").map_within(RangeSet("3-4"))
<RangeSet("3-4")>
>>> RangeSet("10-19").map_within(RangeSet("13-14"))
<RangeSet("3-4")>
>>> RangeSet("10-19 30-39").map_within(RangeSet("17-19 30-32"))
<RangeSet("7-12")>
>>> RangeSet("10-19 30-39").map_within(RangeSet("12-13 17-19 30-32"))
<RangeSet("2-3 7-12")>
"""
out = []
offset = 0
start = None
for p, d in heapq.merge(zip(self.data, itertools.cycle((-5, +5))),
zip(other.data, itertools.cycle((-1, +1)))):
if d == -5:
start = p
elif d == +5:
offset += p-start
start = None
else:
out.append(offset + p - start)
return RangeSet(data=out)
if __name__ == "__main__":
import doctest
doctest.testmod()