Handout

kernel/device/keydecoder.h

@@ -0,0 +1,40 @@
+/*! \file
+ *  \brief \ref KeyDecoder decodes a keystroke to the corresponding \ref Key
+ * object
+ */
+
+#pragma once
+#include "../object/key.h"
+#include "../types.h"
+
+/*! \brief Decoder for \ref ps2keyboardset1 "keyboard codes" received from the
+ * \ref PS2Controller
+ *  \ingroup io
+ *
+ *  Extracts the make and break codes, modifier and scan codes from the pressed
+ * key.
+ */
+class KeyDecoder {
+	unsigned char prefix;  ///< Prefix byte for keys
+	Key modifier;		   ///< activated modifier keys (e.g., caps lock)
+
+   public:
+	/*! \brief Current state (pressed or released) of all keys.
+	 */
+	bool status[static_cast<size_t>(Key::Scancode::KEYS)];
+
+	/*! \brief Default constructor
+	 */
+	KeyDecoder() {}
+
+	/*! \brief Interprets the  \ref ps2keyboardset1 "make and break codes"
+	 * received from the keyboard and derives the corresponding scan code and
+	 * further information about other pressed keys, such as \key{shift} and
+	 * \key{ctrl}.
+	 *
+	 * \param code Byte from Keyboard to decode
+	 * \return Pressed key (\ref Key::valid returns `false` if the key is not
+	 * yet complete)
+	 */
+	Key decode(unsigned char code);
+};