nmon/internal/simagent/oid.go

package simagent

import "strings"

// cmpOID compares dotted OIDs arc by arc as unsigned integers. A leading dot
// is ignored.
func cmpOID(a, b string) int {
	a, b = strings.TrimPrefix(a, "."), strings.TrimPrefix(b, ".")
	for {
		if a == "" || b == "" {
			switch {
			case a == "" && b == "":
				return 0
			case a == "":
				return -1
			}
			return 1
		}
		var x, y uint64
		i, j := 0, 0
		for i < len(a) && a[i] != '.' {
			x = x*10 + uint64(a[i]-'0')
			i++
		}
		for j < len(b) && b[j] != '.' {
			y = y*10 + uint64(b[j]-'0')
			j++
		}
		if x != y {
			if x < y {
				return -1
			}
			return 1
		}
		a, b = strings.TrimPrefix(a[i:], "."), strings.TrimPrefix(b[j:], ".")
	}
}

// hasOIDPrefix reports whether oid is strictly below prefix.
func hasOIDPrefix(oid, prefix string) bool {
	return len(oid) > len(prefix) && oid[len(prefix)] == '.' && oid[:len(prefix)] == prefix
}

func validOID(s string) bool {
	if s == "" {
		return false
	}
	prev := byte('.')
	for i := 0; i < len(s); i++ {
		c := s[i]
		if c == '.' && prev == '.' || c != '.' && (c < '0' || c > '9') {
			return false
		}
		prev = c
	}
	return prev != '.'
}