From cf9e6b932e3ecef9b2c96865174c45ce2b32b394 Mon Sep 17 00:00:00 2001
From: Lawrence Nahum <lawrence@greenaddress.it>
Date: Wed, 15 May 2024 13:39:17 +0200
Subject: [PATCH] avoid unnecessary memcpy

---
 src/utils.cpp      | 4 +---
 src/utils.hpp      | 2 +-
 src/xoshiro256.cpp | 3 +--
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/utils.cpp b/src/utils.cpp
index 23de7c3..8e5669f 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -24,10 +24,8 @@ using namespace std;
 
 namespace ur {
 
-ByteVector sha256(const ByteVector &buf) {
-    array<uint8_t,SHA256_DIGEST_LENGTH> digest;
+void sha256(const ByteVector &buf, std::array<uint8_t, SHA256_DIGEST_LENGTH> &digest) {
     sha256_Raw(buf.data(), buf.size(), digest.data());
-    return {digest.begin(), digest.end()};
 }
 
 ByteVector crc32_bytes(const ByteVector &buf) {
diff --git a/src/utils.hpp b/src/utils.hpp
index e362828..1a74f45 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -20,7 +20,7 @@ namespace ur {
 using ByteVector = std::vector<uint8_t>;
 using StringVector = std::vector<std::string>;
 
-ByteVector sha256(const ByteVector &buf);
+void sha256(const ByteVector &buf, std::array<uint8_t, 32> &digest);
 ByteVector crc32_bytes(const ByteVector &buf);
 uint32_t crc32_int(const ByteVector &buf);
 
diff --git a/src/xoshiro256.cpp b/src/xoshiro256.cpp
index 58b589f..fa91ab0 100644
--- a/src/xoshiro256.cpp
+++ b/src/xoshiro256.cpp
@@ -54,9 +54,8 @@ void Xoshiro256::set_s(const std::array<uint8_t, 32>& a) {
 }
 
 void Xoshiro256::hash_then_set_s(const ByteVector& bytes) {
-    auto digest = sha256(bytes);
     std::array<uint8_t, 32> a;
-    memcpy(a.data(), &digest[0], 32);
+    sha256(bytes, a);
     set_s(a);
 }