minor codec improvements

include/quill/core/Codec.h

@@ -176,14 +176,14 @@ struct Codec
       // Copy the length first and then the actual string
       size_t const len = arg.length();
       std::memcpy(buffer, &len, sizeof(len));
+      buffer += sizeof(len);
 
-      if (len != 0)
+      if (QUILL_LIKELY(len != 0))
       {
         // copy the string, no need to zero terminate it as we got the length
-        std::memcpy(buffer + sizeof(len), arg.data(), arg.length());
+        std::memcpy(buffer, arg.data(), len);
+        buffer += len;
       }
-
-      buffer += sizeof(len) + len;
     }
     else
     {
@@ -219,8 +219,9 @@ struct Codec
       // for std::string we first need to retrieve the length
       size_t len;
       std::memcpy(&len, buffer, sizeof(len));
-      std::string_view arg = std::string_view{reinterpret_cast<char const*>(buffer + sizeof(size_t)), len};
-      buffer += sizeof(len) + len;
+      buffer += sizeof(len);
+      std::string_view const arg = std::string_view{reinterpret_cast<char const*>(buffer), len};
+      buffer += len;
       return arg;
     }
     else

include/quill/std/Pair.h

@@ -26,11 +26,11 @@ struct Codec<std::pair<T1, T2>>
   static size_t compute_encoded_size(detail::SizeCacheVector& conditional_arg_size_cache,
                                      std::pair<T1, T2> const& arg) noexcept
   {
-    // Explicitly separate the calls to ensure the order of evaluation is maintained on MSVC,
-    // as it may evaluate the expressions in a different order, leading to side effects.
-    auto const first_size = Codec<T1>::compute_encoded_size(conditional_arg_size_cache, arg.first);
-    auto const second_size = Codec<T2>::compute_encoded_size(conditional_arg_size_cache, arg.second);
-    return first_size + second_size;
+    // Explicitly separate the calls to ensure the order of evaluation is maintained,
+    // as the compiler may evaluate the expressions in a different order, leading to side effects.
+    size_t total_size = Codec<T1>::compute_encoded_size(conditional_arg_size_cache, arg.first);
+    total_size += Codec<T2>::compute_encoded_size(conditional_arg_size_cache, arg.second);
+    return total_size;
   }
 
   static void encode(std::byte*& buffer, detail::SizeCacheVector const& conditional_arg_size_cache,