From 935226b047f8311a72c432587ed3fac68786429c Mon Sep 17 00:00:00 2001
From: Andrew Ayer <andrew@sslmate.com>
Date: Thu, 16 Feb 2023 20:27:20 -0500
Subject: [PATCH] merkletree: use math/bits.OnesCount64 for efficiency

---
 merkletree/collapsed_tree.go | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/merkletree/collapsed_tree.go b/merkletree/collapsed_tree.go
index e138207..d0525bd 100644
--- a/merkletree/collapsed_tree.go
+++ b/merkletree/collapsed_tree.go
@@ -12,6 +12,7 @@ package merkletree
 import (
 	"encoding/json"
 	"fmt"
+	"math/bits"
 )
 
 type CollapsedTree struct {
@@ -20,12 +21,7 @@ type CollapsedTree struct {
 }
 
 func calculateNumNodes(size uint64) int {
-	numNodes := 0
-	for size > 0 {
-		numNodes += int(size & 1)
-		size >>= 1
-	}
-	return numNodes
+	return bits.OnesCount64(size)
 }
 
 func EmptyCollapsedTree() *CollapsedTree {