refactoring

upnp/statevariable/utils_binary.go

@@ -0,0 +1,62 @@
+package stateVariables
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"strings"
+)
+
+// toBinary tries to convert v into a []byte.
+// - if v is []byte, returns it directly
+// - if v is string, attempts base64 decode, then hex decode
+func toBinary(v interface{}) ([]byte, error) {
+	switch val := v.(type) {
+	case []byte:
+		return val, nil
+
+	case string:
+		// Try base64 first
+		if data, err := base64.StdEncoding.DecodeString(val); err == nil {
+			return data, nil
+		}
+
+		// Try hex next
+		if data, err := hex.DecodeString(val); err == nil {
+			return data, nil
+		}
+
+		return nil, fmt.Errorf("cannot parse string as base64 or hex: %q", val)
+
+	default:
+		return nil, fmt.Errorf("cannot convert type %T to binary", v)
+	}
+}
+
+// decodeBinary decodes Base64 or Hex-encoded binary strings to byte slices
+func decodeBinary(t StateVarType, val string) ([]byte, error) {
+	switch t {
+	case StateType_BinBase64:
+		data, err := base64.StdEncoding.DecodeString(val)
+		if err != nil {
+			return nil, fmt.Errorf("invalid base64: %v", err)
+		}
+		return data, nil
+
+	case StateType_BinHex:
+		// Accept even-length hex string
+		val = strings.TrimSpace(val)
+		if len(val)%2 != 0 {
+			return nil, fmt.Errorf("invalid hex: odd-length string")
+		}
+		data := make([]byte, len(val)/2)
+		_, err := hex.Decode(data, []byte(val))
+		if err != nil {
+			return nil, fmt.Errorf("invalid hex: %v", err)
+		}
+		return data, nil
+
+	default:
+		return nil, fmt.Errorf("decodeBinary: unsupported binary type %v", t)
+	}
+}