Clean up handling and loading of ISO2 country codes

handler-details.go

@@ -98,7 +98,7 @@ func (h Handler) detailsPost(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	country, err := ISO3CountryFromString(r.FormValue("country"))
+	country, err := ISO2CountryCodeFromString(r.FormValue("country"))
 	if err != nil {
 		httpError(w, "can't parse country", nil, http.StatusBadRequest)
 		return

vino.go

@@ -32,7 +32,7 @@ type ISO2CountryCode [2]byte
 
 var UnknownCountry = ISO2CountryCode{'X', 'X'}
 
-func ISO3CountryFromString(s string) (ISO2CountryCode, error) {
+func ISO2CountryCodeFromString(s string) (ISO2CountryCode, error) {
 	if len(s) == 0 {
 		return UnknownCountry, nil
 	}
@@ -45,6 +45,10 @@ func ISO3CountryFromString(s string) (ISO2CountryCode, error) {
 }
 
 func (i ISO2CountryCode) String() string {
+	if i[0] == 0 || i[1] == 0 {
+		return "XX"
+	}
+
 	return fmt.Sprintf("%c%c", i[0], i[1])
 }
 
@@ -59,7 +63,7 @@ func (i *ISO2CountryCode) UnmarshalBinary(d []byte) error {
 		return nil
 	}
 
-	*i = ISO2CountryCode{d[0], d[1]}
+	copy(i[:], d)
 
 	return nil
 }