From f29a7e7970349eec2c76f3c0eda3d5accdd3aa6b Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Sun, 14 Jul 2024 12:40:21 -0700
Subject: [PATCH] Don't use memcpy in append

---
 include/fmt/base.h | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index 4d6a33bc..a2a05d40 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -930,12 +930,9 @@ template <typename T> class buffer {
       try_reserve(size_ + count);
       auto free_cap = capacity_ - size_;
       if (free_cap < count) count = free_cap;
-      if (std::is_same<T, U>::value) {
-        memcpy(ptr_ + size_, begin, count * sizeof(T));
-      } else {
-        T* out = ptr_ + size_;
-        for (size_t i = 0; i < count; ++i) out[i] = begin[i];
-      }
+      // A loop is faster than memcpy on small sizes.
+      T* out = ptr_ + size_;
+      for (size_t i = 0; i < count; ++i) out[i] = begin[i];
       size_ += count;
       begin += count;
     }
@@ -1217,14 +1214,6 @@ FMT_CONSTEXPR auto copy(InputIt begin, InputIt end, OutputIt out) -> OutputIt {
   return out;
 }
 
-template <typename T>
-FMT_CONSTEXPR auto copy(const T* begin, const T* end, T* out) -> T* {
-  if (is_constant_evaluated()) return copy<T, const T*, T*>(begin, end, out);
-  auto size = to_unsigned(end - begin);
-  if (size > 0) memcpy(out, begin, size * sizeof(T));
-  return out + size;
-}
-
 template <typename T, typename V, typename OutputIt>
 FMT_CONSTEXPR auto copy(basic_string_view<V> s, OutputIt out) -> OutputIt {
   return copy<T>(s.begin(), s.end(), out);