perf: optimize hot-path loops, data structures, and cache locality

1 files changed, 31 insertions, 35 deletions

diff --git a/src/wayland/pointer.c b/src/wayland/pointer.c
index 5924eb1..065669f 100644
--- a/src/wayland/pointer.c
+++ b/src/wayland/pointer.c
@@ -248,8 +248,9 @@ static void press_queue_flush(struct seat *s, struct press_queue *q,
                               struct yasl_mouse_event like)
 {
     int kept = 0;
-    for (int i = 0; i < q->n; i++) {
-        struct pending_press p = q->ev[i];
+    int count = q->n;
+    for (int i = 0; i < count; i++) {
+        struct pending_press p = q->ev[(q->head + i) & 7];
         if (only && p.surface != only) {
             q->ev[kept++] = p;
             continue;
@@ -263,26 +264,30 @@ static void press_queue_flush(struct seat *s, struct press_queue *q,
         ev.kind = (enum yasl_pointer_kind)p.release;
         push_mouse(s, p.surface, ev);
     }
+    q->head = 0;
     q->n = kept;
 }
 
 static void press_queue_push(struct press_queue *q, struct wayland_surface *w,
                              struct yasl_vector2i pos, int button, bool release)
 {
-    if (q->n == (int)(sizeof(q->ev) / sizeof(q->ev[0]))) {
-        memmove(q->ev, q->ev + 1, sizeof(q->ev[0]) * (size_t)(q->n - 1));
+    if (q->n == 8) {
+        q->head = (q->head + 1) & 7;
         q->n--;
     }
-    q->ev[q->n++] = (struct pending_press){
+    q->ev[(q->head + q->n) & 7] = (struct pending_press){
         .surface = w, .pos = pos, .button = button, .release = release,
     };
+    q->n++;
 }
 
 static void press_queue_forget(struct press_queue *q, struct wayland_surface *w)
 {
-    for (int i = 0; i < q->n; i++)
-        if (q->ev[i].surface == w)
-            q->ev[i].surface = NULL;
+    for (int i = 0; i < q->n; i++) {
+        int idx = (q->head + i) & 7;
+        if (q->ev[idx].surface == w)
+            q->ev[idx].surface = NULL;
+    }
 }
 
 void seat_pointer_reset(struct seat *s)
@@ -566,28 +571,7 @@ static struct yasl_vector2i touch_pos(const struct touch_point *p)
     };
 }
 
-static int touch_count(const struct seat *s)
-{
-    int n = 0;
-    for (int i = 0; i < SEAT_TOUCH_POINTS; i++)
-        if (s->touch_points[i].active && !s->touch_points[i].up)
-            n++;
-    return n;
-}
 
-static double touch_centroid_y(const struct seat *s, const struct wayland_surface *on)
-{
-    double sum = 0;
-    int n = 0;
-    for (int i = 0; i < SEAT_TOUCH_POINTS; i++) {
-        const struct touch_point *p = &s->touch_points[i];
-        if (p->active && !p->up && p->surface == on) {
-            sum += p->y;
-            n++;
-        }
-    }
-    return n ? sum / n : 0;
-}
 
 static void touch_report(struct seat *s, struct touch_point *p, int button,
                          enum yasl_pointer_kind kind)
@@ -641,24 +625,35 @@ static void touch_frame(void *data, struct wl_touch *touch)
 {
     (void)touch;
     struct seat *s = data;
+    int active_n = 0;
+    double centroid_sum = 0;
+    int centroid_n = 0;
     for (int i = 0; i < SEAT_TOUCH_POINTS; i++) {
         struct touch_point *p = &s->touch_points[i];
-        if (p->active && p->down && !s->touch_primary && !s->touch_scrolling) {
+        if (!p->active) continue;
+        if (p->down && !s->touch_primary && !s->touch_scrolling) {
             s->touch_primary = p;
             s->touch_pressed = true;
             touch_report(s, p, 0, YASL_PTR_PRESS);
         }
+        if (!p->up) {
+            active_n++;
+            if (s->touch_primary && p->surface == s->touch_primary->surface) {
+                centroid_sum += p->y;
+                centroid_n++;
+            }
+        }
     }
     struct touch_point *primary = s->touch_primary;
-    if (primary && !s->touch_scrolling && touch_count(s) >= 2) {
+    if (primary && !s->touch_scrolling && active_n >= 2) {
         if (s->touch_pressed)
             touch_report(s, primary, 0, YASL_PTR_RELEASE);
         s->touch_pressed = false;
         s->touch_scrolling = true;
-        s->touch_scroll_y = touch_centroid_y(s, primary->surface);
+        s->touch_scroll_y = centroid_n ? centroid_sum / centroid_n : 0;
         s->touch_scroll_rest = 0;
-    } else if (s->touch_scrolling && primary && touch_count(s) >= 2) {
-        double y = touch_centroid_y(s, primary->surface);
+    } else if (s->touch_scrolling && primary && active_n >= 2) {
+        double y = centroid_n ? centroid_sum / centroid_n : 0;
         double dy = y - s->touch_scroll_y;
         s->touch_scroll_y = y;
         if (dy != 0.0) {
@@ -679,6 +674,7 @@ static void touch_frame(void *data, struct wl_touch *touch)
         struct touch_point *p = &s->touch_points[i];
         if (!p->active) continue;
         if (p->up) {
+            active_n--;
             if (p == s->touch_primary) {
                 if (s->touch_pressed)
                     touch_report(s, p, 0, YASL_PTR_RELEASE);
@@ -690,7 +686,7 @@ static void touch_frame(void *data, struct wl_touch *touch)
             p->down = p->moved = false;
         }
     }
-    if (!touch_count(s))
+    if (active_n <= 0)
         s->touch_scrolling = false;
 }