Closes #23

core/dbc_decoder.h

@@ -104,7 +104,22 @@ public:
     DecodedFrameValue Decode(const DecodeDatabase &database,
                              const RawCanFrame &frame) const;
 
+    /**
+     * @brief Decode selected signals in selection order using stable keys.
+     * An empty selection returns no signals. Multiplex selectors are read internally.
+     * Frame status summarizes selected signals; short payload still takes precedence.
+     * Unknown frames return UnknownFrame before checking the selection.
+     * @throws std::invalid_argument for a foreign frame key, unknown signal, or duplicate key.
+     */
+    DecodedFrameValue Decode(const DecodeDatabase &database,
+                             const RawCanFrame &frame,
+                             const std::vector<SignalKey> &selection) const;
+
 private:
+    DecodedFrameValue DecodeImpl(const DecodeDatabase &database,
+                                 const RawCanFrame &frame,
+                                 const std::vector<SignalKey> *selection) const;
+
     static bool IsValidDefinition(const DecodeSignal &signal, std::uint8_t dlc);
 
     struct SelectorState {