# 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 non-overlapping ranges on integers.
Attributes:
monotonic: Whether the input has all its integers in increasing order.
extra: A dict that can be used by the caller, e.g. to store info that's
only meaningful to caller.
"""
def __init__(self, data=None):
self.monotonic = False
self._extra = {}
if isinstance(data, str):
self._parse_internal(data)
elif data:
assert len(data) % 2 == 0
self.data = tuple(self._remove_pairs(data))
self.monotonic = all(x < y for x, y in zip(self.data, self.data[1:]))
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() + '")>'
@property
def extra(self):
return self._extra
@classmethod
def parse(cls, text):
"""Parses a text string into a RangeSet.
The input text string consists of a space-separated list of blocks and
ranges, e.g. "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 the 'monotonic'
attribute of the returned RangeSet will be 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)
@classmethod
def parse_raw(cls, text):
"""Parse a string generated by RangeSet.to_string_raw().
>>> RangeSet.parse_raw(RangeSet("0-9").to_string_raw())
<RangeSet("0-9")>
"""
raw = [int(i) for i in text.split(',')]
assert raw[0] == len(raw[1:]), "Invalid raw string."
return cls(data=raw[1:])
def _parse_internal(self, text):
data = []
last = -1
monotonic = True
for p in text.split():
if "-" in p:
s, e = (int(x) for x in p.split("-"))
data.append(s)
data.append(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 = False
data.sort()
self.data = tuple(self._remove_pairs(data))
self.monotonic = monotonic
@staticmethod
def _remove_pairs(source):
"""Remove consecutive duplicate items to simplify the result.
[1, 2, 2, 5, 5, 10] will become [1, 10]."""
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):
assert self.data
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 _, 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)
def extend(self, n):
"""Extend the RangeSet by 'n' blocks.
The lower bound is guaranteed to be non-negative.
>>> RangeSet("0-9").extend(1)
<RangeSet("0-10")>
>>> RangeSet("10-19").extend(15)
<RangeSet("0-34")>
>>> RangeSet("10-19 30-39").extend(4)
<RangeSet("6-23 26-43")>
>>> RangeSet("10-19 30-39").extend(10)
<RangeSet("0-49")>
"""
out = self
for i in range(0, len(self.data), 2):
s, e = self.data[i:i+2]
s1 = max(0, s - n)
e1 = e + n
out = out.union(RangeSet(str(s1) + "-" + str(e1-1)))
return out
def first(self, n):
"""Return the RangeSet that contains at most the first 'n' integers.
>>> RangeSet("0-9").first(1)
<RangeSet("0")>
>>> RangeSet("10-19").first(5)
<RangeSet("10-14")>
>>> RangeSet("10-19").first(15)
<RangeSet("10-19")>
>>> RangeSet("10-19 30-39").first(3)
<RangeSet("10-12")>
>>> RangeSet("10-19 30-39").first(15)
<RangeSet("10-19 30-34")>
>>> RangeSet("10-19 30-39").first(30)
<RangeSet("10-19 30-39")>
>>> RangeSet("0-9").first(0)
<RangeSet("")>
"""
if self.size() <= n:
return self
out = []
for s, e in self:
if e - s >= n:
out += (s, s+n)
break
else:
out += (s, e)
n -= e - s
return RangeSet(data=out)
def next_item(self):
"""Return the next integer represented by the RangeSet.
>>> list(RangeSet("0-9").next_item())
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(RangeSet("10-19 3-5").next_item())
[3, 4, 5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
>>> list(RangeSet("10-19 3 5 7").next_item())
[3, 5, 7, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
"""
for s, e in self:
for element in range(s, e):
yield element
if __name__ == "__main__":
import doctest
doctest.testmod()