vendor: add github.com/d2g

vendor/github.com/d2g/dhcp4/option.go

@@ -0,0 +1,40 @@
+package dhcp4
+
+type OptionCode byte
+
+type Option struct {
+	Code  OptionCode
+	Value []byte
+}
+
+// Map of DHCP options
+type Options map[OptionCode][]byte
+
+// SelectOrderOrAll has same functionality as SelectOrder, except if the order
+// param is nil, whereby all options are added (in arbitary order).
+func (o Options) SelectOrderOrAll(order []byte) []Option {
+	if order == nil {
+		opts := make([]Option, 0, len(o))
+		for i, v := range o {
+			opts = append(opts, Option{Code: i, Value: v})
+		}
+		return opts
+	}
+	return o.SelectOrder(order)
+}
+
+// SelectOrder returns a slice of options ordered and selected by a byte array
+// usually defined by OptionParameterRequestList.  This result is expected to be
+// used in ReplyPacket()'s []Option parameter.
+func (o Options) SelectOrder(order []byte) []Option {
+	opts := make([]Option, 0, len(order))
+	for _, v := range order {
+		if data, ok := o[OptionCode(v)]; ok {
+			opts = append(opts, Option{Code: OptionCode(v), Value: data})
+		}
+	}
+	return opts
+}
+
+type OpCode byte
+type MessageType byte // Option 53