arch/sim: report the keyboard the way the contract says

The X11 keyboard reported any keysym that its translation table did not
know as an ordinary key press carrying the raw keysym.  An application
looking for a byte of text got 65307 for Escape and 65289 for Tab, and
the modifiers arrived as 65505 and friends.

That is not a character, so it cannot be a KEYBOARD_PRESS.  NXDoom on
the simulator has therefore had no menu, no map and no fire, which is
most of the game.

Escape and Tab are control characters and are reported as such.  The
eight modifiers get the keycodes that the codec now has for them.  And a
keysym above the Latin-1 range that no table knows is not reported at
all, which closes the case rather than the three instances of it.

Verified by dumping the events while typing:  Escape arrives as 27, Tab
as 9, the modifiers as keycodes 88 to 95, and the game plays.

Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>

arch/sim/src/sim/sim_keyboard.c

@@ -28,6 +28,7 @@
 #include <sys/types.h>
 
 #include <assert.h>
+#include <nuttx/ascii.h>
 #include <nuttx/debug.h>
 #include <string.h>
 
@@ -66,6 +67,31 @@ static struct sim_dev_s g_simkeyboard;
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: translate_x11_ascii
+ *
+ * Description:
+ *   Translate the X11 key codes that stand for an ASCII control character
+ *   rather than for a special key.  Escape and Tab have no keycode in
+ *   enum kbd_keycode_e because they need none:  they are characters, and
+ *   an application looks for them as such.
+ *
+ * Returns: The character, or zero if this key is not one of them.
+ ****************************************************************************/
+
+static uint32_t translate_x11_ascii(uint32_t code)
+{
+  switch (code)
+    {
+    case XK_Escape:
+      return ASCII_ESC;
+    case XK_Tab:
+      return ASCII_TAB;
+    default:
+      return 0;
+    }
+}
+
 /****************************************************************************
  * Name: translate_x11_key
  *
@@ -154,6 +180,28 @@ static uint32_t translate_x11_key(uint32_t code)
 
       /* Context-specific function keys */
 
+      /* Modifier keys.  These produce no character of their own, so an
+       * application that wants to know that one is held down has no other
+       * way to find out.
+       */
+
+    case XK_Shift_L:
+      return KEYCODE_LSHIFT;
+    case XK_Shift_R:
+      return KEYCODE_RSHIFT;
+    case XK_Control_L:
+      return KEYCODE_LCTRL;
+    case XK_Control_R:
+      return KEYCODE_RCTRL;
+    case XK_Alt_L:
+      return KEYCODE_LALT;
+    case XK_Alt_R:
+      return KEYCODE_RALT;
+    case XK_Super_L:
+      return KEYCODE_LGUI;
+    case XK_Super_R:
+      return KEYCODE_RGUI;
+
     case XK_F1:
       return KEYCODE_F1;
     case XK_F2:
@@ -263,10 +311,33 @@ void sim_kbdevent(uint32_t key, bool is_press)
       return;
     }
 
+  iinfo("key=%04x\n", key);
+
+  /* A few keysyms are control characters rather than special keys, and an
+   * application expects them as the character.
+   */
+
+  trans_key = translate_x11_ascii(key);
+  if (trans_key != 0)
+    {
+      keyboard_event(&priv->lower, trans_key, types[0][is_press]);
+      return;
+    }
+
   trans_key = translate_x11_key(key);
   is_special = trans_key != KEYCODE_NORMAL;
+
+  /* A keysym outside the Latin-1 range that no table knows about is not a
+   * character.  Reporting it as one would hand the application a value
+   * such as 65307 where it expects a byte of text.
+   */
+
+  if (!is_special && key > 0xff)
+    {
+      return;
+    }
+
   trans_key = is_special ? trans_key : key;
-  iinfo("key=%04x\n", key);
 
   /* Report data changes */