Improve sequential initialization of HAMTs

With this implementation, it uses transients also when using a tracing garbage collector -- before it would be optimized only when using reference counting.
arximboldi · Jun 2, 2022 · 160ba64 · 160ba64
1 parent 72a565e
commit 160ba64
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Showing 4 changed files with 37 additions and 27 deletions.
diff --git a/immer/detail/hamts/champ.hpp b/immer/detail/hamts/champ.hpp
@@ -89,6 +89,28 @@ struct champ
             node_t::delete_deep(root, 0);
     }
 
+    template <typename U>
+    static auto from_initializer_list(std::initializer_list<U> values)
+    {
+        auto e      = owner_t{};
+        auto result = champ{empty()};
+        for (auto&& v : values)
+            result.add_mut(e, v);
+        return result;
+    }
+
+    template <typename Iter,
+              typename Sent,
+              std::enable_if_t<compatible_sentinel_v<Iter, Sent>, bool> = true>
+    static auto from_range(Iter first, Sent last)
+    {
+        auto e      = owner_t{};
+        auto result = champ{empty()};
+        for (; first != last; ++first)
+            result.add_mut(e, *first);
+        return result;
+    }
+
     template <typename Fn>
     void for_each_chunk(Fn&& fn) const
     {

diff --git a/immer/map.hpp b/immer/map.hpp
@@ -170,10 +170,8 @@ class map
      * Constructs a map containing the elements in `values`.
      */
     map(std::initializer_list<value_type> values)
-    {
-        for (auto&& v : values)
-            *this = std::move(*this).insert(v);
-    }
+        : impl_{impl_t::from_initializer_list(values)}
+    {}
 
     /*!
      * Constructs a map containing the elements in the range
@@ -184,10 +182,8 @@ class map
               std::enable_if_t<detail::compatible_sentinel_v<Iter, Sent>,
                                bool> = true>
     map(Iter first, Sent last)
-    {
-        for (; first != last; ++first)
-            *this = std::move(*this).insert(*first);
-    }
+        : impl_{impl_t::from_range(first, last)}
+    {}
 
     /*!
      * Default constructor.  It creates a map of `size() == 0`.  It

diff --git a/immer/set.hpp b/immer/set.hpp
@@ -95,10 +95,8 @@ class set
      * Constructs a set containing the elements in `values`.
      */
     set(std::initializer_list<value_type> values)
-    {
-        for (auto&& v : values)
-            *this = std::move(*this).insert(v);
-    }
+        : impl_{impl_t::from_initializer_list(values)}
+    {}
 
     /*!
      * Constructs a set containing the elements in the range
@@ -109,10 +107,8 @@ class set
               std::enable_if_t<detail::compatible_sentinel_v<Iter, Sent>,
                                bool> = true>
     set(Iter first, Sent last)
-    {
-        for (; first != last; ++first)
-            *this = std::move(*this).insert(*first);
-    }
+        : impl_{impl_t::from_range(first, last)}
+    {}
 
     /*!
      * Returns an iterator pointing at the first element of the

diff --git a/immer/table.hpp b/immer/table.hpp
@@ -186,10 +186,8 @@ class table
      * Constructs a table containing the elements in `values`.
      */
     table(std::initializer_list<value_type> values)
-    {
-        for (auto&& v : values)
-            *this = std::move(*this).insert(v);
-    }
+        : impl_{impl_t::from_initializer_list(values)}
+    {}
 
     /*!
      * Constructs a table containing the elements in the range
@@ -200,10 +198,8 @@ class table
               std::enable_if_t<detail::compatible_sentinel_v<Iter, Sent>,
                                bool> = true>
     table(Iter first, Sent last)
-    {
-        for (; first != last; ++first)
-            *this = std::move(*this).insert(*first);
-    }
+        : impl_{impl_t::from_range(first, last)}
+    {}
 
     /*!
      * Default constructor.  It creates a table of `size() == 0`. It
@@ -467,16 +463,16 @@ class table
     table&& update_move(std::true_type, key_type k, Fn&& fn)
     {
         impl_.template update_mut<project_value, default_value, combine_value>(
-            std::move(k), std::forward<Fn>(fn));
+            {}, std::move(k), std::forward<Fn>(fn));
         return std::move(*this);
     }
 
     template <typename Fn>
     table update_move(std::false_type, key_type k, Fn&& fn)
     {
         return impl_
-            .template update_mut<project_value, default_value, combine_value>(
-                {}, std::move(k), std::forward<Fn>(fn));
+            .template update<project_value, default_value, combine_value>(
+                std::move(k), std::forward<Fn>(fn));
     }
 
     table&& erase_move(std::true_type, const key_type& value)