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dense_set: emplace always consumes its arguments

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This commit is contained in:
Michele Caini
2022-02-14 15:15:34 +01:00
parent 02d1417ef4
commit a4b8b93e7f
2 changed files with 22 additions and 26 deletions
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2
TODO
View File

@@ -4,7 +4,7 @@
* add examples (and credits) from @alanjfs :)
WIP:
* dense map/set: support uses-allocator construction
* dense map/set: support uses-allocator construction (single arg, multi-arg, key construction)
* runtime events (emitter)
* iterator based try_emplace vs try_insert for perf reasons
* registry: remove reference to basic_sparse_set<E>

46
src/entt/container/dense_set.hpp
View File

@@ -273,27 +273,6 @@ class dense_set {
return cend();
}
template<typename Arg>
[[nodiscard]] auto get_or_emplace(Arg &&arg) {
const auto hash = sparse.second()(arg);
auto index = hash_to_bucket(hash);
if(auto it = constrained_find(arg, index); it != end()) {
return std::make_pair(it, false);
}
if(const auto count = size() + 1u; count > (bucket_count() * max_load_factor())) {
rehash(bucket_count() * 2u);
index = hash_to_bucket(hash);
}
packed.first().emplace_back(sparse.first()[index], std::forward<Arg>(arg));
// update goes after emplace to enforce exception guarantees
sparse.first()[index] = size() - 1u;
return std::make_pair(--end(), true);
}
template<typename Other>
bool do_erase(const Other &value) {
for(size_type *curr = sparse.first().data() + bucket(value); *curr != std::numeric_limits<size_type>::max(); curr = &packed.first()[*curr].next) {
@@ -557,6 +536,10 @@ public:
/**
* @brief Constructs an element in-place, if it does not exist.
*
* The element is also constructed when the container already has the key,
* in which case the newly constructed object is destroyed immediately.
*
* @tparam Args Types of arguments to forward to the constructor of the
* element.
* @param args Arguments to forward to the constructor of the element.
@@ -566,11 +549,24 @@ public:
*/
template<typename... Args>
std::pair<iterator, bool> emplace(Args &&...args) {
if constexpr(((sizeof...(Args) == 1u) && ... && std::is_same_v<std::remove_const_t<std::remove_reference_t<Args>>, value_type>)) {
return get_or_emplace(std::forward<Args>(args)...);
} else {
return get_or_emplace(value_type{std::forward<Args>(args)...});
auto &node = packed.first().emplace_back(packed.first().size(), std::forward<Args>(args)...);
const auto hash = sparse.second()(node.element);
auto index = hash_to_bucket(hash);
if(auto it = constrained_find(node.element, index); it != end()) {
packed.first().pop_back();
return std::make_pair(it, false);
}
// update goes after emplace to enforce exception guarantees
node.next = std::exchange(sparse.first()[index], size() - 1u);
if(const auto count = size() + 1u; count > (bucket_count() * max_load_factor())) {
rehash(bucket_count() * 2u);
index = hash_to_bucket(hash);
}
return std::make_pair(--end(), true);
}
/**