From ad3a67a2a0dc815219593a7aae306db8ed8ec3a3 Mon Sep 17 00:00:00 2001
From: Philipp Otterbein <potterbein@blockstream.com>
Date: Sat, 7 Dec 2024 04:42:04 +0100
Subject: [PATCH] optimize string concat

---
 src/libutil/util.hh | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 0fb6ff837..4d5683e2b 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -338,7 +338,9 @@ std::string showBytes(uint64_t bytes);
  */
 inline std::string operator + (const std::string & s1, std::string_view s2)
 {
-    auto s = s1;
+    std::string s;
+    s.reserve(s1.size() + s2.size());
+    s.append(s1);
     s.append(s2);
     return s;
 }
@@ -351,10 +353,11 @@ inline std::string operator + (std::string && s, std::string_view s2)
 
 inline std::string operator + (std::string_view s1, const char * s2)
 {
+    auto s2Size = strlen(s2);
     std::string s;
-    s.reserve(s1.size() + strlen(s2));
+    s.reserve(s1.size() + s2Size);
     s.append(s1);
-    s.append(s2);
+    s.append(s2, s2Size);
     return s;
 }