1 # Copyright (C) 2014 The Android Open Source Project 2 # 3 # Licensed under the Apache License, Version 2.0 (the "License"); 4 # you may not use this file except in compliance with the License. 5 # You may obtain a copy of the License at 6 # 7 # http://www.apache.org/licenses/LICENSE-2.0 8 # 9 # Unless required by applicable law or agreed to in writing, software 10 # distributed under the License is distributed on an "AS IS" BASIS, 11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 # See the License for the specific language governing permissions and 13 # limitations under the License. 14 15 from __future__ import print_function 16 import heapq 17 import itertools 18 19 __all__ = ["RangeSet"] 20 21 class RangeSet(object): 22 """A RangeSet represents a set of nonoverlapping ranges on the 23 integers (ie, a set of integers, but efficient when the set contains 24 lots of runs.""" 25 26 def __init__(self, data=None): 27 if data: 28 self.data = tuple(self._remove_pairs(data)) 29 else: 30 self.data = () 31 32 def __iter__(self): 33 for i in range(0, len(self.data), 2): 34 yield self.data[i:i+2] 35 36 def __eq__(self, other): 37 return self.data == other.data 38 def __ne__(self, other): 39 return self.data != other.data 40 def __nonzero__(self): 41 return bool(self.data) 42 43 def __str__(self): 44 if not self.data: 45 return "empty" 46 else: 47 return self.to_string() 48 49 @classmethod 50 def parse(cls, text): 51 """Parse a text string consisting of a space-separated list of 52 blocks and ranges, eg "10-20 30 35-40". Ranges are interpreted to 53 include both their ends (so the above example represents 18 54 individual blocks. Returns a RangeSet object. 55 56 If the input has all its blocks in increasing order, then returned 57 RangeSet will have an extra attribute 'monotonic' that is set to 58 True. For example the input "10-20 30" is monotonic, but the input 59 "15-20 30 10-14" is not, even though they represent the same set 60 of blocks (and the two RangeSets will compare equal with ==). 61 """ 62 63 data = [] 64 last = -1 65 monotonic = True 66 for p in text.split(): 67 if "-" in p: 68 s, e = p.split("-") 69 data.append(int(s)) 70 data.append(int(e)+1) 71 if last <= s <= e: 72 last = e 73 else: 74 monotonic = False 75 else: 76 s = int(p) 77 data.append(s) 78 data.append(s+1) 79 if last <= s: 80 last = s+1 81 else: 82 monotonic = True 83 data.sort() 84 r = RangeSet(cls._remove_pairs(data)) 85 r.monotonic = monotonic 86 return r 87 88 @staticmethod 89 def _remove_pairs(source): 90 last = None 91 for i in source: 92 if i == last: 93 last = None 94 else: 95 if last is not None: 96 yield last 97 last = i 98 if last is not None: 99 yield last 100 101 def to_string(self): 102 out = [] 103 for i in range(0, len(self.data), 2): 104 s, e = self.data[i:i+2] 105 if e == s+1: 106 out.append(str(s)) 107 else: 108 out.append(str(s) + "-" + str(e-1)) 109 return " ".join(out) 110 111 def to_string_raw(self): 112 return str(len(self.data)) + "," + ",".join(str(i) for i in self.data) 113 114 def union(self, other): 115 """Return a new RangeSet representing the union of this RangeSet 116 with the argument.""" 117 out = [] 118 z = 0 119 for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))), 120 zip(other.data, itertools.cycle((+1, -1)))): 121 if (z == 0 and d == 1) or (z == 1 and d == -1): 122 out.append(p) 123 z += d 124 return RangeSet(data=out) 125 126 def intersect(self, other): 127 """Return a new RangeSet representing the intersection of this 128 RangeSet with the argument.""" 129 out = [] 130 z = 0 131 for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))), 132 zip(other.data, itertools.cycle((+1, -1)))): 133 if (z == 1 and d == 1) or (z == 2 and d == -1): 134 out.append(p) 135 z += d 136 return RangeSet(data=out) 137 138 def subtract(self, other): 139 """Return a new RangeSet representing subtracting the argument 140 from this RangeSet.""" 141 142 out = [] 143 z = 0 144 for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))), 145 zip(other.data, itertools.cycle((-1, +1)))): 146 if (z == 0 and d == 1) or (z == 1 and d == -1): 147 out.append(p) 148 z += d 149 return RangeSet(data=out) 150 151 def overlaps(self, other): 152 """Returns true if the argument has a nonempty overlap with this 153 RangeSet.""" 154 155 # This is like intersect, but we can stop as soon as we discover the 156 # output is going to be nonempty. 157 z = 0 158 for p, d in heapq.merge(zip(self.data, itertools.cycle((+1, -1))), 159 zip(other.data, itertools.cycle((+1, -1)))): 160 if (z == 1 and d == 1) or (z == 2 and d == -1): 161 return True 162 z += d 163 return False 164 165 def size(self): 166 """Returns the total size of the RangeSet (ie, how many integers 167 are in the set).""" 168 169 total = 0 170 for i, p in enumerate(self.data): 171 if i % 2: 172 total += p 173 else: 174 total -= p 175 return total 176
