[WIP] Sort LongPressMappings

plugins/Kaleidoscope-LongPress/src/kaleidoscope/plugin/LongPress.h

@@ -48,8 +48,41 @@ struct LongPressMapping {
   // This constructor is here so that we can create an empty LongPress object in RAM
   // into which we can copy the values from a PROGMEM LongPress object.
   LongPressMapping() = default;
+
+
+  /// Compare two LongPressMapping objects to sort mappings on KeyAddr
+  /// always before mappings on Key objects.
+  /// Intended to be used with the qsort function.
+  static int compare(const LongPressMapping m1, const LongPressMapping m2) {
+    if (m1.addr != m2.addr) {
+      if (m1.addr == KeyAddr::none()) {
+        // if m1 is not specified by physical key address (but m2 is), m2
+        // must be sorted first)
+        return 1;
+      }
+
+      if (m2.addr == KeyAddr::none()) {
+        // if m2 is not specified by physical key address (but m1 is), m1
+        // must be sorted first)
+        return -1;
+      }
+    }
+
+    // in all other cases sort order is not relevant for us, but we just
+    // sort by the Key then.
+    if (m1.key == m2.key) {
+      return 0;
+    }
+
+    if (m1.key > m2.key) {
+      return -1;
+    }
+
+    return 1;
+  }
 };
 
+
 // =============================================================================
 /// Kaleidoscope plugin for long-press keys
 ///
@@ -267,6 +300,17 @@ class LongPress : public Plugin {
   void configureLongPresses(LongPressMapping const (&explicitmappings)[_explicitmappings_count]) {
     explicitmappings_       = explicitmappings;
     explicitmappings_count_ = _explicitmappings_count;
+    // sort the mappings to put all mappings on KeyAddr before mappings on
+    // Key. This is necessary to let mappings on KeyAddr take precedence
+    // over mappings on Key regardless of the order they were defined in
+    // “explicitmappings”.
+    if (explicitmappings_count_ > 0) {
+      int length = sizeof(explicitmappings_) / sizeof(explicitmappings_[0]);
+      qsort(explicitmappings_,
+            length,
+            sizeof(explicitmappings_[0]),
+            LongPressMapping::compare);
+    }
   }
 
  private: