1 files changed, 104 insertions, 0 deletions
diff --git a/common/layer_switch.c b/common/layer_switch.c
new file mode 100644
index 0000000000..22bfb34f65
--- /dev/null
+++ b/common/layer_switch.c
@@ -0,0 +1,104 @@
+#include <stdint.h>
+#include "keyboard.h"
+#include "action.h"
+#include "debug.h"
+#include "util.h"
+#include "layer_switch.h"
+
+
+uint8_t default_layer = 0;
+
+uint16_t layer_switch_stat = 0;
+
+
+uint16_t layer_switch_get_stat(void)
+{
+    return layer_switch_stat;
+}
+
+/* return highest layer whose state is on */
+uint8_t layer_switch_get_layer(void)
+{
+    return biton16(layer_switch_stat);
+}
+
+static inline void stat_set(uint16_t stat)
+{
+    debug("layer_switch: ");
+    layer_switch_debug(); debug(" to ");
+
+    layer_switch_stat = stat;
+
+    layer_switch_debug(); debug("\n");
+
+    clear_keyboard_but_mods(); // To avoid stuck keys
+}
+
+void layer_switch_clear(void)
+{
+    stat_set(0);
+}
+
+
+void layer_switch_set(uint16_t stat)
+{
+    stat_set(stat);
+}
+
+void layer_switch_move(uint8_t layer)
+{
+    if (layer)
+        stat_set(1<<layer);
+    else
+        stat_set(0);    // fall back to default layer
+}
+
+void layer_switch_on(uint8_t layer)
+{
+    stat_set(layer_switch_stat | (1<<layer));
+}
+
+void layer_switch_off(uint8_t layer)
+{
+    stat_set(layer_switch_stat & ~(1<<layer));
+}
+
+void layer_switch_invert(uint8_t layer)
+{
+    stat_set(layer_switch_stat ^ (1<<layer));
+}
+
+void layer_switch_or(uint16_t stat)
+{
+    stat_set(layer_switch_stat | stat);
+}
+void layer_switch_and(uint16_t stat)
+{
+    stat_set(layer_switch_stat & stat);
+}
+void layer_switch_xor(uint16_t stat)
+{
+    stat_set(layer_switch_stat ^ stat);
+}
+
+void layer_switch_debug(void)
+{
+    debug_hex16(layer_switch_stat); debug("("); debug_dec(layer_switch_get_layer()); debug(")");
+}
+
+action_t layer_switch_get_action(key_t key)
+{
+    action_t action;
+    action.code = ACTION_TRANSPARENT;
+
+    /* higher layer first */
+    for (int8_t i = 15; i >= 0; i--) {
+        if (layer_switch_stat & (1<<i)) {
+            action = action_for_key(i, key);
+            if (action.code != ACTION_TRANSPARENT) {
+                return action;
+            }
+        }
+    }
+    return action;
+}