container: hmap fixups

include/mcl/container/detail/meta_byte_group.hpp

@@ -134,7 +134,7 @@ struct meta_byte_group {
 
     bool is_all_empty_or_tombstone() const
     {
-        return match_empty_or_tombstone() const == 0xffff;
+        return match_empty_or_tombstone() == 0xffff;
     }
 
     meta_byte get(size_t index) const
@@ -154,7 +154,7 @@ struct meta_byte_group {
 
 #    define MCL_HMAP_MATCH_META_BYTE_GROUP(MATCH, ...)                                           \
         {                                                                                        \
-            for (const u32 match_result{MATCH}; match_result != 0; match_result &= match_result - 1) { \
+            for (u16 match_result{MATCH}; match_result != 0; match_result &= match_result - 1) { \
                 const size_t match_index{static_cast<size_t>(std::countr_zero(match_result))};   \
                 __VA_ARGS__                                                                      \
             }                                                                                    \
@@ -162,7 +162,7 @@ struct meta_byte_group {
 
 #    define MCL_HMAP_MATCH_META_BYTE_GROUP_EXCEPT_LAST(MATCH, ...)                                                              \
         {                                                                                                                       \
-            for (const u32 match_result{(MATCH) & (0x7fff)}; match_result != 0; match_result &= match_result - 1) { \
+            for (u16 match_result{static_cast<u16>((MATCH) & (0x7fff))}; match_result != 0; match_result &= match_result - 1) { \
                 const size_t match_index{static_cast<size_t>(std::countr_zero(match_result))};                                  \
                 __VA_ARGS__                                                                                                     \
             }                                                                                                                   \

include/mcl/container/detail/slot_union.hpp

@@ -9,6 +9,7 @@ namespace mcl::detail {
 template<typename ValueType>
 union slot_union {
     slot_union() {}
+    ~slot_union() {}
     ValueType value;
 };
 

include/mcl/container/hmap.hpp

@@ -16,8 +16,10 @@
 #include "mcl/container/detail/slot_union.hpp"
 #include "mcl/hash/xmrx.hpp"
 #include "mcl/hint/assume.hpp"
+#include "mcl/memory/overaligned_unique_ptr.hpp"
 
 namespace mcl {
+
 template<typename KeyType, typename MappedType, typename Hash, typename Pred>
 class hmap;
 
@@ -127,13 +129,15 @@ public:
     using const_iterator = hmap_iterator<true, key_type, mapped_type, hasher, key_equal>;
 
 private:
-    using slot_type = detail::slot_union<value_type>;
-    static_assert(!std::is_reference_v<key_type>);
-    static_assert(!std::is_reference_v<mapped_type>);
-
     static constexpr size_t group_size{detail::meta_byte_group::max_group_size};
     static constexpr size_t average_max_group_load{group_size - 2};
 
+    using slot_type = detail::slot_union<value_type>;
+    using slot_ptr = std::unique_ptr<slot_type[]>;
+    using meta_byte_ptr = overaligned_unique_ptr<group_size, detail::meta_byte[]>;
+    static_assert(!std::is_reference_v<key_type>);
+    static_assert(!std::is_reference_v<mapped_type>);
+
 public:
     hmap()
     {
@@ -501,8 +505,8 @@ private:
         // DEBUG_ASSERT(group_count != 0 && std::ispow2(group_count));
 
         group_index_mask = group_count - 1;
-        mbs = std::unique_ptr<detail::meta_byte[]>{new (std::align_val_t(group_size)) detail::meta_byte[group_count * group_size + 1]};
+        mbs = make_overaligned_unique_ptr_array<group_size, detail::meta_byte>(group_count * group_size + 1);
-        slots = std::unique_ptr<slot_type[]>{new slot_type[group_count * group_size]};
+        slots = slot_ptr{new slot_type[group_count * group_size]};
 
         clear_metadata();
     }
@@ -521,8 +525,8 @@ private:
     std::size_t group_index_mask;
     std::size_t empty_slots;
     std::size_t full_slots;
-    std::unique_ptr<detail::meta_byte[]> mbs;
+    meta_byte_ptr mbs;
-    std::unique_ptr<slot_type[]> slots;
+    slot_ptr slots;
 };
 
 }  // namespace mcl

include/mcl/container/ihmap.hpp

@@ -470,7 +470,7 @@ private:
     {
         group_type& g{groups[pos.group_index]};
 
-        g.slots[pos.slot_index].value->~value_type();
+        g.slots[pos.slot_index].value.~value_type();
 
         --full_slots;
         if (g.meta.is_any_empty()) {

include/mcl/hash/xmrx.hpp

@@ -4,6 +4,8 @@
 
 // Reference: http://jonkagstrom.com/bit-mixer-construction/
 
+#pragma once
+
 #include <functional>
 
 #include "mcl/bit/rotate.hpp"