Minor optimization for linear search

Add a small loop unrolling to when BGEN_MAYBELESSEQUAL is set.
tidwall · Dec 20, 2024 · da4b935 · da4b935
1 parent 5fbb5a1
commit da4b935
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/bgen.h b/bgen.h
@@ -927,6 +927,12 @@ static int BGEN_SYM(search_linear)(BGEN_ITEM *items, int nitems, BGEN_ITEM key,
     int i = 0;
     *found = 0;
 #ifdef BGEN_MAYBELESSEQUAL
+    while (nitems-i >= 4) {
+        if (BGEN_SYM(maybelessequal)(key, items[i], udata)){goto compare;}i++;
+        if (BGEN_SYM(maybelessequal)(key, items[i], udata)){goto compare;}i++;
+        if (BGEN_SYM(maybelessequal)(key, items[i], udata)){goto compare;}i++;
+        if (BGEN_SYM(maybelessequal)(key, items[i], udata)){goto compare;}i++;
+    }
     for (; i < nitems; i++) {
         if (BGEN_SYM(maybelessequal)(key, items[i], udata)) {
             goto compare;

diff --git a/tests/test_spatial2x.c b/tests/test_spatial2x.c
@@ -40,8 +40,9 @@ static void shuffle_points(struct point *array, size_t numels) {
 #define BGEN_FANOUT     4
 #define BGEN_COUNTED
 #define BGEN_SPATIAL
-#define BGEN_ITEMRECT   { point_rect(item, min, max); }
-#define BGEN_COMPARE    { return point_compare(a, b); }
+#define BGEN_ITEMRECT       { point_rect(item, min, max); }
+#define BGEN_MAYBELESSEQUAL { return a.curve <= b.curve; }
+#define BGEN_COMPARE        { return point_compare(a, b); }
 #include "../bgen.h"