Add alternative hostname and service name helpers

alternative.go

@@ -0,0 +1,32 @@
+package avahi
+
+// #include <stdlib.h>
+// #include <avahi-common/alternative.h>
+import "C"
+import "unsafe"
+
+func AlternativeHostname(hostname string) (string, error) {
+	chostname := C.CString(hostname)
+	defer C.free(unsafe.Pointer(chostname))
+
+	alt := C.avahi_alternative_host_name(chostname)
+	if alt == nil {
+		return "", ErrNoMemory
+	}
+
+	defer C.free(unsafe.Pointer(alt))
+	return C.GoString(alt), nil
+}
+
+func AlternativeServiceName(name string) (string, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	alt := C.avahi_alternative_service_name(cname)
+	if alt == nil {
+		return "", ErrNoMemory
+	}
+
+	defer C.free(unsafe.Pointer(alt))
+	return C.GoString(alt), nil
+}

alternative_test.go

@@ -0,0 +1,43 @@
+//go:build linux || freebsd
+
+package avahi
+
+import "testing"
+
+func TestAlternativeHostname(t *testing.T) {
+	hostname := "test-hostname"
+
+	for i := 0; i < 10; i++ {
+		alt, err := AlternativeHostname(hostname)
+		if err != nil {
+			t.Fatalf("AlternativeHostname failed: %v", err)
+		}
+
+		t.Logf("Alternative hostname: %s", alt)
+
+		if alt == hostname {
+			t.Fatalf("AlternativeHostname did not return an alternative name")
+		}
+
+		hostname = alt
+	}
+}
+
+func TestAlternativeServiceName(t *testing.T) {
+	serviceName := "test-service"
+
+	for i := 0; i < 10; i++ {
+		alt, err := AlternativeServiceName(serviceName)
+		if err != nil {
+			t.Fatalf("AlternativeServiceName failed: %v", err)
+		}
+
+		t.Logf("Alternative service name: %s", alt)
+
+		if alt == serviceName {
+			t.Fatalf("AlternativeServiceName did not return an alternative name")
+		}
+
+		serviceName = alt
+	}
+}