From ccf8cdcbb57f0f858a25d6335be39329666f52bb Mon Sep 17 00:00:00 2001
From: Trinidadec <msden.ua@gmail.com>
Date: Fri, 27 Oct 2023 22:10:39 +0300
Subject: [PATCH] optimize highestOne256 (#24)

---
 subtree.mjs | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/subtree.mjs b/subtree.mjs
index b5b3b11..980ac14 100644
--- a/subtree.mjs
+++ b/subtree.mjs
@@ -18,13 +18,10 @@ const nodeHeight = 2
 
 /** @type {(bu256: bigint) => bigint} */
 const highestOne256 = bu256 => {
-    let result = 0n
-    let index = 256n
-    while (bu256 !== 0n) {
-        index >>= 1n
-        if (index === 0n) {
-            return result + 1n
-        }
+    if (bu256 === 0n) { return 0n }
+    let result = 1n
+    let index = 128n
+    while (true) {
         const high = bu256 >> index
         if (high === 0n) {
             bu256 &= (1n << index) - 1n
@@ -32,8 +29,9 @@ const highestOne256 = bu256 => {
             bu256 = high
             result += index
         }
+        if (index === 1n) { return result }
+        index >>= 1n
     }
-    return result
 }
 
 /** @type {(bu256: bigint) => bigint} */