keysym: add xkb_keysym_to_{lower,upper}

These functions are needed later; they are not API functions. The
capitalization is not locale sensitive.

Signed-off-by: Ran Benita <ran234@gmail.com>

src/keysym.c

@@ -242,6 +242,26 @@ xkb_keysym_is_upper(xkb_keysym_t ks)
     return (ks == upper ? true : false);
 }
 
+xkb_keysym_t
+xkb_keysym_to_lower(xkb_keysym_t ks)
+{
+    xkb_keysym_t lower, upper;
+
+    XConvertCase(ks, &lower, &upper);
+
+    return lower;
+}
+
+xkb_keysym_t
+xkb_keysym_to_upper(xkb_keysym_t ks)
+{
+    xkb_keysym_t lower, upper;
+
+    XConvertCase(ks, &lower, &upper);
+
+    return upper;
+}
+
 /*
  * The following is copied verbatim from libX11:src/KeyBind.c, commit
  * d45b3fc19fbe95c41afc4e51d768df6d42332010, with the following changes:

src/keysym.h

@@ -59,4 +59,10 @@ xkb_keysym_is_upper(xkb_keysym_t keysym);
 bool
 xkb_keysym_is_keypad(xkb_keysym_t keysym);
 
+xkb_keysym_t
+xkb_keysym_to_upper(xkb_keysym_t ks);
+
+xkb_keysym_t
+xkb_keysym_to_lower(xkb_keysym_t ks);
+
 #endif

test/keysym.c

@@ -183,5 +183,18 @@ main(void)
     assert(!xkb_keysym_is_keypad(XKB_KEY_1));
     assert(!xkb_keysym_is_keypad(XKB_KEY_Return));
 
+    assert(xkb_keysym_to_upper(XKB_KEY_a) == XKB_KEY_A);
+    assert(xkb_keysym_to_upper(XKB_KEY_A) == XKB_KEY_A);
+    assert(xkb_keysym_to_lower(XKB_KEY_a) == XKB_KEY_a);
+    assert(xkb_keysym_to_lower(XKB_KEY_A) == XKB_KEY_a);
+    assert(xkb_keysym_to_upper(XKB_KEY_Return) == XKB_KEY_Return);
+    assert(xkb_keysym_to_lower(XKB_KEY_Return) == XKB_KEY_Return);
+    assert(xkb_keysym_to_upper(XKB_KEY_Greek_lambda) == XKB_KEY_Greek_LAMBDA);
+    assert(xkb_keysym_to_upper(XKB_KEY_Greek_LAMBDA) == XKB_KEY_Greek_LAMBDA);
+    assert(xkb_keysym_to_lower(XKB_KEY_Greek_lambda) == XKB_KEY_Greek_lambda);
+    assert(xkb_keysym_to_lower(XKB_KEY_Greek_LAMBDA) == XKB_KEY_Greek_lambda);
+    assert(xkb_keysym_to_upper(XKB_KEY_eacute) == XKB_KEY_Eacute);
+    assert(xkb_keysym_to_lower(XKB_KEY_Eacute) == XKB_KEY_eacute);
+
     return 0;
 }