-
Notifications
You must be signed in to change notification settings - Fork 390
/
set.go
86 lines (74 loc) · 1.73 KB
/
set.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
// Copyright (C) 2023 Storj Labs, Inc.
// See LICENSE for copying information.
package intset
import "math/bits"
const (
bucketBits = 32
)
// Set set of int values.
type Set struct {
size int
bits []uint32
count int
}
// NewSet creates new int set.
func NewSet(size int) Set {
return Set{
size: size,
bits: make([]uint32, (size+(bucketBits-1))/bucketBits),
}
}
// Contains returns true if set includes int value.
// Ignores negative values and above set length.
func (s Set) Contains(value int) bool {
if value < 0 || value >= s.size {
return false
}
bucket, bit := offset(value)
return (s.bits[bucket] & (uint32(1) << bit)) != 0
}
// Include includes int value into set.
// Ignores negative values and above set length.
func (s *Set) Include(value int) {
if value < 0 || value >= s.size {
return
}
if !s.Contains(value) {
bucket, bit := offset(value)
s.bits[bucket] |= (uint32(1) << bit)
s.count++
}
}
// Exclude removes int value from set.
// Ignores negative values and above set length.
func (s *Set) Exclude(value int) {
if value < 0 || value >= s.size {
return
}
if s.Contains(value) {
bucket, bit := offset(value)
s.bits[bucket] &= ^(uint32(1) << bit)
s.count--
}
}
// Count returns number of int values in a set.
func (s Set) Count() int {
return s.count
}
func offset(value int) (bucket, bit int) {
return value / bucketBits, value % bucketBits
}
// Add adds to the set content of other sets.
// Sources sets with different size than target will be ignored.
func (s *Set) Add(sources ...Set) {
s.count = 0
for k, b := range s.bits {
for srci := range sources {
if s.size == sources[srci].size {
b |= sources[srci].bits[k]
}
}
s.bits[k] = b
s.count += bits.OnesCount32(s.bits[k])
}
}