From d49828f291fa53350cc8a5c3f027059fc64d961a Mon Sep 17 00:00:00 2001
From: Roy Jacobson <roi.jacobson1@gmail.com>
Date: Sun, 21 Aug 2022 21:24:23 +0300
Subject: [PATCH] Replace mapping.emplace(K, V) with call to mapping.find(K)
 and branching to reduce the amount of allocations.

---
 include/cereal/details/helpers.hpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/cereal/details/helpers.hpp b/include/cereal/details/helpers.hpp
index 8dafb8ec..48e93f50 100644
--- a/include/cereal/details/helpers.hpp
+++ b/include/cereal/details/helpers.hpp
@@ -412,8 +412,13 @@ namespace cereal
 
       std::uint32_t find( std::size_t hash, std::uint32_t version )
       {
-        const auto result = mapping.emplace( hash, version );
-        return result.first->second;
+        auto it = mapping.find(hash);
+        if (it == mapping.end()) {
+          mapping.emplace(hash, version);
+          return version;
+        }
+        else
+          return it->second;
       }
     }; // struct Versions
   } // namespace detail