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path: root/ber/obj.go
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package ber

import "strconv"

type OID []int

func base128(n int) (b []byte) {
	if n == 0 {
		return []byte{0}
	}
	l := 0
	for i := n; i > 0; i >>= 7 {
		l++
	}
	for i := l - 1; i >= 0; i-- {
		o := byte(n >> uint(i*7))
		o &= 0x7F
		if i != 0 {
			o |= 0x80
		}
		b = append(b, o)
	}
	return
}

func debase128(b []byte) (i, n int) {
	for _, v := range b {
		i <<= 7
		i |= int(v & 0x7f)
		n++
		if v & 0x80 == 0 {
			return
		}
	}
	return
}

func marshalOID(obj OID) (b []byte) {
	if len(obj) < 2 || obj[0] > 2 {
		return []byte{}
	}
	if obj[0] < 2 && obj[1] > 39 {
		return []byte{}
	}
	first := obj[0]*40 + obj[1]
	b = append(b, base128(first)...)
	for _, o := range obj[2:] {
		b = append(b, base128(o)...)
	}
	return b
}

func unmarshalOID(b []byte) OID {
	return OID{}
}

func (o OID) Marshal() ([]byte, error) {
	b := marshalOID(o)
	return b, nil
}

func UnmarshalOID(b []byte) (o OID) {
	o = append(o, int(b[0])/40)
	o = append(o, int(b[0])%40)
	b = b[2:]
	for i := 0; i < len(b); {
		d, n := debase128(b[i:])
		o = append(o, d)
		i += n
	}
	return
}

func (o OID) String() (s string) {
	for i, v := range o {
		if i != 0 {
			s += "."
		}
		s += strconv.Itoa(v)
	}
	return
}