Initial import

protocol/aprs/address.go

@@ -0,0 +1,106 @@
+package aprs
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var (
+	ErrAddressInvalid = errors.New(`aprs: invalid address`)
+)
+
+type Address struct {
+	Call       string `json:"call"`
+	SSID       string `json:"ssid,omitempty"`
+	IsRepeated bool   `json:"is_repeated,omitempty"`
+}
+
+func (a Address) EqualTo(b Address) bool {
+	return a.Call == b.Call && a.SSID == b.SSID
+}
+
+func (a Address) String() string {
+	var r = ""
+
+	if a.IsRepeated {
+		r = "*"
+	}
+	if a.SSID == "" {
+		return a.Call + r
+	}
+	return fmt.Sprintf("%s-%s%s", a.Call, a.SSID, r)
+}
+
+func (a Address) Secret() int16 {
+	var h = int16(0x73e2)
+	var c = a.Call
+
+	if len(c)%2 > 0 {
+		c += "\x00"
+	}
+	for i := 0; i < len(c); i += 2 {
+		h ^= int16(c[i]) << 8
+		h ^= int16(c[i+1])
+	}
+	return h & 0x7fff
+}
+
+func ParseAddress(s string) (Address, error) {
+	r := strings.HasSuffix(s, "*")
+	if r {
+		s = s[:len(s)-1]
+	}
+	p := strings.Split(s, "-")
+	if len(p) == 0 || len(p) > 2 {
+		return Address{}, ErrAddressInvalid
+	}
+
+	a := Address{Call: p[0], IsRepeated: r}
+	if len(p) == 2 {
+		a.SSID = p[1]
+	}
+
+	return a, nil
+}
+
+func MustParseAddress(s string) Address {
+	a, err := ParseAddress(s)
+	if err != nil {
+		panic(err)
+	}
+	return a
+}
+
+func IsQConstruct(call string) bool {
+	return len(call) == 3 && call[0] == 'q'
+}
+
+type Path []Address
+
+func (p Path) String() string {
+	var s = make([]string, len(p))
+	for i, a := range p {
+		s[i] = a.String()
+	}
+	return strings.Join(s, ",")
+}
+
+func ParsePath(p string) (Path, error) {
+	ss := strings.Split(p, ",")
+
+	if len(ss) == 0 {
+		return nil, nil
+	}
+
+	var err error
+	as := make(Path, len(ss))
+	for i, s := range ss {
+		as[i], err = ParseAddress(s)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return as, nil
+}