[libcxx-commits] [libcxx] [libc++] Refactor some code in monotonic_buffer_resource (PR #117271)

[Louis Dionne via libcxx-commits]

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@@ -429,23 +429,18 @@ static void* align_down(size_t align, size_t size, void*& ptr, size_t& space) {
   return ptr;
 }
 
-void* monotonic_buffer_resource::__initial_descriptor::__try_allocate_from_chunk(size_t bytes, size_t align) {
-  if (!__cur_)
-    return nullptr;
-  void* new_ptr       = static_cast<void*>(__cur_);
-  size_t new_capacity = (__cur_ - __start_);
-  void* aligned_ptr   = align_down(align, bytes, new_ptr, new_capacity);
-  if (aligned_ptr != nullptr)
-    __cur_ = static_cast<char*>(new_ptr);
-  return aligned_ptr;
-}
-
-void* monotonic_buffer_resource::__chunk_footer::__try_allocate_from_chunk(size_t bytes, size_t align) {
-  void* new_ptr       = static_cast<void*>(__cur_);
-  size_t new_capacity = (__cur_ - __start_);
+template <bool is_initial, typename Chunk>
+void* __try_allocate_from_chunk(Chunk& self, size_t bytes, size_t align) {
+  if constexpr (is_initial) {
+    // here only for __initial_descriptor
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ldionne wrote:

Instead, could you please explain *why* this is only done for the initial descriptor?

https://github.com/llvm/llvm-project/pull/117271