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dense set:

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* cleaned up implementation
* uses-allocator construction support
* a few more tests
This commit is contained in:
Michele Caini
2022-02-19 09:30:39 +01:00
parent 380cb41ca9
commit dc5a72cda5
3 changed files with 39 additions and 82 deletions
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2
TODO
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@@ -4,7 +4,7 @@
* add examples (and credits) from @alanjfs :)
WIP:
* uses-allocator construction: dense set (review), dense map, compressed pair, any (with allocator support), cache, dispatcher, poly, ...
* uses-allocator construction: dense map, compressed pair, any (with allocator support), cache, dispatcher, poly, ...
* process scheduler: reviews, use free lists internally
* runtime events (emitter)
* iterator based try_emplace vs try_insert for perf reasons

98
src/entt/container/dense_set.hpp
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@@ -27,63 +27,11 @@ namespace entt {
namespace internal {
template<typename Type, typename Allocator>
struct dense_set_node final: Allocator {
using allocator_type = Allocator;
template<typename... Args>
dense_set_node(const std::size_t pos, Args &&...args)
: dense_set_node{std::allocator_arg, Allocator{}, pos, std::forward<Args>(args)...} {
}
template<typename... Args>
dense_set_node(std::allocator_arg_t, const allocator_type &alloc, const std::size_t pos, Args &&...args)
: Allocator{alloc},
next{pos} {
std::allocator_traits<allocator_type>::construct(*this, reinterpret_cast<Type *>(&instance), std::forward<Args>(args)...);
}
dense_set_node(const dense_set_node &other)
: dense_set_node{std::allocator_arg, Allocator{}, other} {
}
dense_set_node(std::allocator_arg_t, const allocator_type &alloc, const dense_set_node &other)
: Allocator{alloc},
next{other.next} {
std::allocator_traits<allocator_type>::construct(*this, reinterpret_cast<Type *>(&instance), other.element());
}
dense_set_node(dense_set_node &&other)
: dense_set_node{std::allocator_arg, Allocator{}, std::move(other)} {
}
dense_set_node(std::allocator_arg_t, const allocator_type &alloc, dense_set_node &&other)
: Allocator{alloc},
next{other.next} {
std::allocator_traits<allocator_type>::construct(*this, reinterpret_cast<Type *>(&instance), std::move(other.element()));
}
~dense_set_node() {
std::destroy_at(reinterpret_cast<const Type *>(&instance));
}
const Type &element() const ENTT_NOEXCEPT {
return *reinterpret_cast<const Type *>(&instance);
}
Type &element() ENTT_NOEXCEPT {
return *reinterpret_cast<Type *>(&instance);
}
std::size_t next;
std::aligned_storage_t<sizeof(Type)> instance;
};
template<typename It>
class dense_set_iterator final {
friend dense_set_iterator<const std::remove_pointer_t<It> *>;
using iterator_traits = std::iterator_traits<decltype(std::addressof(std::as_const(std::declval<It>()->element())))>;
using iterator_traits = std::iterator_traits<decltype(std::addressof(std::as_const(std::declval<It>()->second)))>;
public:
using value_type = typename iterator_traits::value_type;
@@ -138,11 +86,11 @@ public:
}
[[nodiscard]] reference operator[](const difference_type value) const ENTT_NOEXCEPT {
return it[value].element();
return it[value].second;
}
[[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
return std::addressof(it->element());
return std::addressof(it->second);
}
[[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
@@ -201,7 +149,7 @@ template<typename It>
class dense_set_local_iterator final {
friend dense_set_local_iterator<const std::remove_pointer_t<It> *>;
using iterator_traits = std::iterator_traits<decltype(std::addressof(std::as_const(std::declval<It>()->element())))>;
using iterator_traits = std::iterator_traits<decltype(std::addressof(std::as_const(std::declval<It>()->second)))>;
public:
using value_type = typename iterator_traits::value_type;
@@ -222,7 +170,7 @@ public:
offset{other.offset} {}
dense_set_local_iterator &operator++() ENTT_NOEXCEPT {
return offset = it[offset].next, *this;
return offset = it[offset].first, *this;
}
dense_set_local_iterator operator++(int) ENTT_NOEXCEPT {
@@ -231,7 +179,7 @@ public:
}
[[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
return std::addressof(it[offset].element());
return std::addressof(it[offset].second);
}
[[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
@@ -284,7 +232,7 @@ class dense_set {
using alloc_traits = std::allocator_traits<Allocator>;
static_assert(std::is_same_v<typename alloc_traits::value_type, Type>);
using node_type = internal::dense_set_node<Type, Allocator>;
using node_type = std::pair<std::size_t, Type>;
using sparse_container_type = std::vector<std::size_t, typename alloc_traits::template rebind_alloc<std::size_t>>;
using packed_container_type = std::vector<node_type, typename alloc_traits::template rebind_alloc<node_type>>;
@@ -316,10 +264,10 @@ class dense_set {
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) {
if(packed.second()(packed.first()[*curr].element(), value)) {
for(size_type *curr = sparse.first().data() + bucket(value); *curr != std::numeric_limits<size_type>::max(); curr = &packed.first()[*curr].first) {
if(packed.second()(packed.first()[*curr].second, value)) {
const auto index = *curr;
*curr = packed.first()[*curr].next;
*curr = packed.first()[*curr].first;
move_and_pop(index);
return true;
}
@@ -330,13 +278,13 @@ class dense_set {
void move_and_pop(const std::size_t pos) {
if(const auto last = size() - 1u; pos != last) {
size_type *curr = sparse.first().data() + bucket(packed.first().back().element());
for(; *curr != last; curr = &packed.first()[*curr].next) {}
size_type *curr = sparse.first().data() + bucket(packed.first().back().second);
for(; *curr != last; curr = &packed.first()[*curr].first) {}
*curr = pos;
// basic exception guarantees when value type has a throwing move constructor
packed.first()[pos].element() = std::move(packed.first().back().element());
packed.first()[pos].next = packed.first().back().next;
packed.first()[pos].second = std::move(packed.first().back().second);
packed.first()[pos].first = packed.first().back().first;
}
packed.first().pop_back();
@@ -591,21 +539,19 @@ public:
*/
template<typename... Args>
std::pair<iterator, bool> emplace(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);
auto &node = packed.first().emplace_back(std::piecewise_construct, std::make_tuple(packed.first().size()), std::forward_as_tuple(std::forward<Args>(args)...));
const auto hash = sparse.second()(node.second);
const auto index = hash_to_bucket(hash);
if(auto it = constrained_find(node.element(), index); it != end()) {
if(auto it = constrained_find(node.second, 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);
node.first = std::exchange(sparse.first()[index], size() - 1u);
if(const auto count = size() + 1u; count > (bucket_count() * max_load_factor())) {
if(size() > (bucket_count() * max_load_factor())) {
rehash(bucket_count() * 2u);
index = hash_to_bucket(hash);
}
return std::make_pair(--end(), true);
@@ -843,8 +789,8 @@ public:
std::fill(sparse.first().begin(), sparse.first().end(), std::numeric_limits<size_type>::max());
for(size_type pos{}, last = size(); pos < last; ++pos) {
const auto index = bucket(packed.first()[pos].element());
packed.first()[pos].next = std::exchange(sparse.first()[index], pos);
const auto index = bucket(packed.first()[pos].second);
packed.first()[pos].first = std::exchange(sparse.first()[index], pos);
}
}
}

21
test/entt/container/dense_set.cpp
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@@ -821,7 +821,7 @@ TEST(DenseSet, Reserve) {
TEST(DenseSet, ThrowingAllocator) {
using allocator = test::throwing_allocator<std::size_t>;
using packed_allocator = test::throwing_allocator<entt::internal::dense_set_node<std::size_t, test::throwing_allocator<std::size_t>>>;
using packed_allocator = test::throwing_allocator<std::pair<std::size_t, std::size_t>>;
using packed_exception = typename packed_allocator::exception_type;
static constexpr std::size_t minimum_bucket_count = 8u;
@@ -836,22 +836,33 @@ TEST(DenseSet, ThrowingAllocator) {
#if defined(ENTT_HAS_TRACKED_MEMORY_RESOURCE)
TEST(DenseSet, NoUsesAllocatorConstruction) {
using allocator = std::pmr::polymorphic_allocator<int>;
test::tracked_memory_resource memory_resource{};
entt::dense_set<int, std::hash<int>, std::equal_to<int>, allocator> set{&memory_resource};
set.reserve(1u);
memory_resource.reset();
set.emplace(0);
ASSERT_EQ(memory_resource.do_allocate_counter(), 0u);
ASSERT_EQ(memory_resource.do_deallocate_counter(), 0u);
}
TEST(DenseSet, UsesAllocatorConstruction) {
using string_type = typename test::tracked_memory_resource::string_type;
using allocator = std::pmr::polymorphic_allocator<string_type>;
test::tracked_memory_resource memory_resource{};
entt::dense_set<string_type, std::hash<string_type>, std::equal_to<string_type>, allocator> set{&memory_resource};
const char *str = "a string long enough to force an allocation (hopefully)";
set.reserve(1u);
memory_resource.reset();
set.emplace(str);
set.emplace(test::tracked_memory_resource::default_value);
ASSERT_GT(memory_resource.do_allocate_counter(), 0u);
ASSERT_EQ(memory_resource.do_deallocate_counter(), 0u);
entt::dense_set<string_type, std::hash<string_type>, std::equal_to<string_type>, allocator> other{std::move(set)};
}
#endif