From b64eff8ecd83cda83e9e68ceaa519bd7742f0cda Mon Sep 17 00:00:00 2001
From: Andrew Ekstedt <andrew.ekstedt@gmail.com>
Date: Sat, 5 Oct 2024 20:16:35 -0700
Subject: [PATCH] add digest.clone method and use it in Sum

---
 sponge.go | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sponge.go b/sponge.go
index f4f14a2..aab872d 100644
--- a/sponge.go
+++ b/sponge.go
@@ -68,8 +68,13 @@ func keccakf(a *[25]uint64) {
 	}
 }
 
-func (d0 *digest) Sum(b []byte) []byte {
-	d := *d0
+func (d *digest) clone() *digest {
+	d0 := *d
+	return &d0
+}
+
+func (d *digest) Sum(b []byte) []byte {
+	d = d.clone()
 	d.buf[d.len] = d.dsbyte
 	bs := d.BlockSize()
 	for i := d.len + 1; i < bs; i++ {