X11: Fix X keycode ranges for XKB and core

This replaces the hardcoded keycode ranges and various kludgy range
checks with the actual ranges reported by Xlib and XKB.

src/x11_init.c

@@ -43,10 +43,6 @@ static int translateKeyCode(int scancode)
 {
     int keySym;
 
-    // Valid key code range is  [8,255], according to the Xlib manual
-    if (scancode < 8 || scancode > 255)
-        return GLFW_KEY_UNKNOWN;
-
     {
         int dummy;
         KeySym* keySyms;
@@ -200,7 +196,7 @@ static int translateKeyCode(int scancode)
 //
 static void createKeyTables(void)
 {
-    int scancode, key;
+    int scancode, key, scancodeMin, scancodeMax;
 
     memset(_glfw.x11.keycodes, -1, sizeof(_glfw.x11.keycodes));
     memset(_glfw.x11.scancodes, -1, sizeof(_glfw.x11.scancodes));
@@ -214,8 +210,11 @@ static void createKeyTables(void)
         XkbDescPtr desc = XkbGetMap(_glfw.x11.display, 0, XkbUseCoreKbd);
         XkbGetNames(_glfw.x11.display, XkbKeyNamesMask, desc);
 
+        scancodeMin = desc->min_key_code;
+        scancodeMax = desc->max_key_code;
+
         // Find the X11 key code -> GLFW key code mapping
-        for (scancode = desc->min_key_code;  scancode <= desc->max_key_code;  scancode++)
+        for (scancode = scancodeMin;  scancode <= scancodeMax;  scancode++)
         {
             memcpy(name, desc->names->keys[scancode].name, XkbKeyNameLength);
             name[XkbKeyNameLength] = '\0';
@@ -345,15 +344,16 @@ static void createKeyTables(void)
             else if (strcmp(name, "COMP") == 0) key = GLFW_KEY_MENU;
             else key = GLFW_KEY_UNKNOWN;
 
-            if ((scancode >= 0) && (scancode < 256))
+            _glfw.x11.keycodes[scancode] = key;
-                _glfw.x11.keycodes[scancode] = key;
         }
 
         XkbFreeNames(desc, XkbKeyNamesMask, True);
         XkbFreeKeyboard(desc, 0, True);
     }
+    else
+        XDisplayKeycodes(_glfw.x11.display, &scancodeMin, &scancodeMax);
 
-    for (scancode = 0;  scancode < 256;  scancode++)
+    for (scancode = scancodeMin;  scancode <= scancodeMax;  scancode++)
     {
         // Translate the un-translated key codes using traditional X11 KeySym
         // lookups
@@ -1069,6 +1069,8 @@ int _glfwPlatformInit(void)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XDestroyIC");
     _glfw.x11.xlib.DestroyWindow = (PFN_XDestroyWindow)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XDestroyWindow");
+    _glfw.x11.xlib.DisplayKeycodes = (PFN_XDisplayKeycodes)
+        _glfw_dlsym(_glfw.x11.xlib.handle, "XDisplayKeycodes");
     _glfw.x11.xlib.EventsQueued = (PFN_XEventsQueued)
         _glfw_dlsym(_glfw.x11.xlib.handle, "XEventsQueued");
     _glfw.x11.xlib.FilterEvent = (PFN_XFilterEvent)

src/x11_platform.h

@@ -67,6 +67,7 @@ typedef int (* PFN_XDeleteContext)(Display*,XID,XContext);
 typedef int (* PFN_XDeleteProperty)(Display*,Window,Atom);
 typedef void (* PFN_XDestroyIC)(XIC);
 typedef int (* PFN_XDestroyWindow)(Display*,Window);
+typedef int (* PFN_XDisplayKeycodes)(Display*,int*,int*);
 typedef int (* PFN_XEventsQueued)(Display*,int);
 typedef Bool (* PFN_XFilterEvent)(XEvent*,Window);
 typedef int (* PFN_XFindContext)(Display*,XID,XContext,XPointer*);
@@ -166,6 +167,7 @@ typedef void (* PFN_Xutf8SetWMProperties)(Display*,Window,const char*,const char
 #define XDeleteProperty _glfw.x11.xlib.DeleteProperty
 #define XDestroyIC _glfw.x11.xlib.DestroyIC
 #define XDestroyWindow _glfw.x11.xlib.DestroyWindow
+#define XDisplayKeycodes _glfw.x11.xlib.DisplayKeycodes
 #define XEventsQueued _glfw.x11.xlib.EventsQueued
 #define XFilterEvent _glfw.x11.xlib.FilterEvent
 #define XFindContext _glfw.x11.xlib.FindContext
@@ -522,6 +524,7 @@ typedef struct _GLFWlibraryX11
         PFN_XDeleteProperty DeleteProperty;
         PFN_XDestroyIC DestroyIC;
         PFN_XDestroyWindow DestroyWindow;
+        PFN_XDisplayKeycodes DisplayKeycodes;
         PFN_XEventsQueued EventsQueued;
         PFN_XFilterEvent FilterEvent;
         PFN_XFindContext FindContext;