Optimize hot loops with direct access, LUTs, and closed-form formulas

1 files changed, 15 insertions, 6 deletions

diff --git a/src/snapshot.c b/src/snapshot.c
index 3869be4..29ed98c 100644
--- a/src/snapshot.c
+++ b/src/snapshot.c
@@ -189,17 +189,26 @@ static bool term_snapshot_update_inner(struct term_snapshot *s, struct term *t)
     if (!all && rows > 1) {
         int cand_k = 0;
         /* Find candidate scroll offset k by checking where top rows moved. */
-        for (int p = 0; p < 2 && p < rows - 1 && !cand_k; p++) {
-            uint64_t key = new_keys[p];
-            if (!key)
-                continue;
-            for (int k = 1; p + k < rows; k++) {
-                if (s->keys[p + k] == key) {
+        uint64_t key0 = new_keys[0];
+        if (key0) {
+            for (int k = 1; k < rows; k++) {
+                if (s->keys[k] == key0) {
                     cand_k = k;
                     break;
                 }
             }
         }
+        if (!cand_k && rows > 2) {
+            uint64_t key1 = new_keys[1];
+            if (key1) {
+                for (int k = 1; 1 + k < rows; k++) {
+                    if (s->keys[1 + k] == key1) {
+                        cand_k = k;
+                        break;
+                    }
+                }
+            }
+        }
 
         if (cand_k > 0) {
             int total = rows - cand_k;