events: improve keyboard modifiers handling

Use remapped key codes (SDL), instead of scan codes, to track modifiers
state.
---
 src/events/SDL_keyboard.c | 134 ++++++++++++++++++++--------------------------
 1 file changed, 57 insertions(+), 77 deletions(-)

diff --git a/src/events/SDL_keyboard.c b/src/events/SDL_keyboard.c
index ed4043e..87c272a 100644
--- a/src/events/SDL_keyboard.c
+++ b/src/events/SDL_keyboard.c
@@ -662,6 +662,8 @@ SDL_SendKeyboardKey(Uint8 state, SDL_Scancode scancode)
 {
     SDL_Keyboard *keyboard = &SDL_keyboard;
     int posted;
+    SDL_Keymod modifier;
+    SDL_Keycode keycode;
     Uint16 modstate;
     Uint32 type;
     Uint8 repeat;
@@ -673,82 +675,6 @@ SDL_SendKeyboardKey(Uint8 state, SDL_Scancode scancode)
     printf("The '%s' key has been %s\n", SDL_GetScancodeName(scancode),
            state == SDL_PRESSED ? "pressed" : "released");
 #endif
-    if (state == SDL_PRESSED) {
-        modstate = keyboard->modstate;
-        switch (scancode) {
-        case SDL_SCANCODE_NUMLOCKCLEAR:
-            keyboard->modstate ^= KMOD_NUM;
-            break;
-        case SDL_SCANCODE_CAPSLOCK:
-            keyboard->modstate ^= KMOD_CAPS;
-            break;
-        case SDL_SCANCODE_LCTRL:
-            keyboard->modstate |= KMOD_LCTRL;
-            break;
-        case SDL_SCANCODE_RCTRL:
-            keyboard->modstate |= KMOD_RCTRL;
-            break;
-        case SDL_SCANCODE_LSHIFT:
-            keyboard->modstate |= KMOD_LSHIFT;
-            break;
-        case SDL_SCANCODE_RSHIFT:
-            keyboard->modstate |= KMOD_RSHIFT;
-            break;
-        case SDL_SCANCODE_LALT:
-            keyboard->modstate |= KMOD_LALT;
-            break;
-        case SDL_SCANCODE_RALT:
-            keyboard->modstate |= KMOD_RALT;
-            break;
-        case SDL_SCANCODE_LGUI:
-            keyboard->modstate |= KMOD_LGUI;
-            break;
-        case SDL_SCANCODE_RGUI:
-            keyboard->modstate |= KMOD_RGUI;
-            break;
-        case SDL_SCANCODE_MODE:
-            keyboard->modstate |= KMOD_MODE;
-            break;
-        default:
-            break;
-        }
-    } else {
-        switch (scancode) {
-        case SDL_SCANCODE_NUMLOCKCLEAR:
-        case SDL_SCANCODE_CAPSLOCK:
-            break;
-        case SDL_SCANCODE_LCTRL:
-            keyboard->modstate &= ~KMOD_LCTRL;
-            break;
-        case SDL_SCANCODE_RCTRL:
-            keyboard->modstate &= ~KMOD_RCTRL;
-            break;
-        case SDL_SCANCODE_LSHIFT:
-            keyboard->modstate &= ~KMOD_LSHIFT;
-            break;
-        case SDL_SCANCODE_RSHIFT:
-            keyboard->modstate &= ~KMOD_RSHIFT;
-            break;
-        case SDL_SCANCODE_LALT:
-            keyboard->modstate &= ~KMOD_LALT;
-            break;
-        case SDL_SCANCODE_RALT:
-            keyboard->modstate &= ~KMOD_RALT;
-            break;
-        case SDL_SCANCODE_LGUI:
-            keyboard->modstate &= ~KMOD_LGUI;
-            break;
-        case SDL_SCANCODE_RGUI:
-            keyboard->modstate &= ~KMOD_RGUI;
-            break;
-        case SDL_SCANCODE_MODE:
-            keyboard->modstate &= ~KMOD_MODE;
-            break;
-        default:
-            break;
-        }
-        modstate = keyboard->modstate;
-    }
 
     /* Figure out what type of event this is */
     switch (state) {
@@ -775,6 +701,60 @@ SDL_SendKeyboardKey(Uint8 state, SDL_Scancode scancode)
     /* Update internal keyboard state */
     keyboard->keystate[scancode] = state;
 
+    keycode = keyboard->keymap[scancode];
+
+    /* Update modifiers state if applicable */
+    switch (keycode) {
+    case SDLK_LCTRL:
+        modifier = KMOD_LCTRL;
+        break;
+    case SDLK_RCTRL:
+        modifier = KMOD_RCTRL;
+        break;
+    case SDLK_LSHIFT:
+        modifier = KMOD_LSHIFT;
+        break;
+    case SDLK_RSHIFT:
+        modifier = KMOD_RSHIFT;
+        break;
+    case SDLK_LALT:
+        modifier = KMOD_LALT;
+        break;
+    case SDLK_RALT:
+        modifier = KMOD_RALT;
+        break;
+    case SDLK_LGUI:
+        modifier = KMOD_LGUI;
+        break;
+    case SDLK_RGUI:
+        modifier = KMOD_RGUI;
+        break;
+    case SDLK_MODE:
+        modifier = KMOD_MODE;
+        break;
+    default:
+        modifier = KMOD_NONE;
+        break;
+    }
+    if (SDL_KEYDOWN == type) {
+        modstate = keyboard->modstate;
+        switch (keycode) {
+        case SDLK_NUMLOCKCLEAR:
+            keyboard->modstate ^= KMOD_NUM;
+            break;
+        case SDLK_CAPSLOCK:
+            keyboard->modstate ^= KMOD_CAPS;
+            break;
+        default:
+            keyboard->modstate |= modifier;
+            break;
+        }
+    }
+    else {
+        keyboard->modstate &= ~modifier;
+        modstate = keyboard->modstate;
+    }
+
     /* Post the event, if desired */
     posted = 0;
     if (SDL_GetEventState(type) == SDL_ENABLE) {
@@ -783,7 +763,7 @@ SDL_SendKeyboardKey(Uint8 state, SDL_Scancode scancode)
         event.key.state = state;
         event.key.repeat = repeat;
         event.key.keysym.scancode = scancode;
-        event.key.keysym.sym = keyboard->keymap[scancode];
+        event.key.keysym.sym = keycode;
         event.key.keysym.mod = modstate;
         event.key.windowID = keyboard->focus ? keyboard->focus->id : 0;
         posted = (SDL_PushEvent(&event) > 0);
-- 
2.1.0