aboutsummaryrefslogtreecommitdiff
path: root/ber/bitstring.go
blob: 7e0fd9379dd47a66ebf68fc32104f6ea33c993aa (plain)
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
package ber

// BitString
type BitString []bool

func UnmarshalBitString(b []byte) (bs BitString) {
	padding := int(b[0])
	length := (len(b)-1)*8 - padding
	for i := 0; i < length; i++ {
		x := 1 + i/8
		y := 7 - uint(i%8)
		bit := b[x]&(1<<y) != 0
		bs = append(bs, bit)
	}
	return
}

func MarshalBitString(bs BitString) (b []byte) {
	padding := (8 - len(bs)%8) % 8
	length := len(bs) / 8
	if padding != 0 {
		length++
	}
	b = make([]byte, length+1)
	b[0] = byte(padding)
	for i, bi := range bs {
		x := 1 + i/8
		y := 7 - uint(i%8)
		if bi {
			b[x] |= 1 << y
		}
	}
	return
}

func (bs BitString) String() (s string) {
	bmap := map[bool]string{
		true:  "1",
		false: "0",
	}
	for i, bit := range bs {
		if i > 0 && i%4 == 0 {
			s += " "
		}
		s += bmap[bit]
	}
	return
}

func (bs BitString) IsSet(n int) bool {
	if n > len(bs) {
		return false
	}
	return bs[n]
}

func (bs *BitString) Set(n int) {
	if len(*bs) < n {
		nbs := make(BitString, n+1)
		copy(nbs, *bs)
		*bs = nbs
	}
	(*bs)[n] = true
}

func (bs *BitString) Clear(n int) {
	if len(*bs) < n {
		nbs := make(BitString, n+1)
		copy(nbs, *bs)
		*bs = nbs
	}
	(*bs)[n] = false
}

func (bs BitString) Equal(s BitString) bool {
	if len(bs) != len(s) {
		return false
	}
	for i := 0; i < len(bs); i++ {
		if bs[i] != s[i] {
			return false
		}
	}
	return true
}