-/*
- * Layer stack
- */
-#define LAYER_STACK_SIZE 8
-typedef struct {
- uint8_t layer:4;
- uint8_t next:3;
- bool used;
-} layer_item_t;
-
-static uint8_t top_layer = 0;
-// [0] is sentinel and not used. [0] is null item.
-static layer_item_t layer_stack[LAYER_STACK_SIZE] = {};
-
-static bool layer_push(uint8_t layer)
-{
- for (uint8_t i = 1; i < LAYER_STACK_SIZE; i++) {
- if (!layer_stack[i].used) {
- layer_stack[i] = (layer_item_t){ .layer = layer,
- .next = top_layer,
- .used = true };
- top_layer = i;
- return true;
- }
- }
- return false;
-}
-static bool layer_pop(void)
-{
- if (layer_stack[top_layer].used) {
- uint8_t popped = top_layer;
- top_layer = layer_stack[popped].next;
- layer_stack[popped] = (layer_item_t){};
- return true;
- }
- return false;
-}
-static bool layer_remove(uint8_t layer)
-{
- if (layer_stack[top_layer].used && layer_stack[top_layer].layer == layer) {
- layer_pop();
- debug("layer_remove: top_layer\n");
- return true;
- }
-
- for (uint8_t i = top_layer; layer_stack[i].used; i = layer_stack[i].next) {
- debug("layer_remove: ["); debug_dec(i); debug("]");
- debug_dec(layer_stack[i].layer); debug("\n");
- uint8_t removed = layer_stack[i].next;
- if (layer_stack[removed].used && layer_stack[removed].layer == layer) {
- layer_stack[i].next = layer_stack[removed].next;
- layer_stack[removed] = (layer_item_t){};
- debug("layer_remove: removed.\n");
- return true;
- }
- }
- return false;
-}
-static bool layer_remove_then_push(uint8_t layer)
-{
- layer_remove(layer);
- return layer_push(layer);
-}
-static bool layer_remove_or_push(uint8_t layer)
-{
- return (layer_remove(layer)) || layer_push(layer);
-}
-static void debug_layer_stack(void)
-{
- debug("layer_stack: ");
- layer_item_t item = layer_stack[top_layer];
- while (item.used) {
- debug_dec(item.layer);
- debug("["); debug_dec(item.next); debug("]");
- item = layer_stack[item.next];
- }
- debug("\n");
-}
-