fix #88

net/packet/util.go

@@ -0,0 +1,51 @@
+package packet
+
+import (
+	"reflect"
+)
+
+type Ary struct {
+	Len Field
+	Ary interface{}
+}
+
+func (a Ary) Encode() (data []byte) {
+	length := int(reflect.ValueOf(a.Len).Int())
+	array := reflect.ValueOf(a.Ary).Elem()
+	for i := 0; i < length; i++ {
+		elem := array.Index(i)
+		data = append(data, elem.Interface().(FieldEncoder).Encode()...)
+	}
+	return
+}
+
+func (a Ary) Decode(r DecodeReader) error {
+	length := int(reflect.ValueOf(a.Len).Int())
+	array := reflect.ValueOf(a.Ary).Elem()
+	for i := 0; i < length; i++ {
+		elem := array.Index(i)
+		if err := elem.Interface().(FieldDecoder).Decode(r); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+type Opt struct {
+	Has   func() bool
+	Field interface{}
+}
+
+func (o Opt) Encode() []byte {
+	if o.Has() {
+		return nil
+	}
+	return o.Field.(FieldEncoder).Encode()
+}
+
+func (o Opt) Decode(r DecodeReader) error {
+	if o.Has() {
+		return nil
+	}
+	return o.Field.(FieldDecoder).Decode(r)
+}