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Slightly optimize FlatHashTable::resize.

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This commit is contained in:
levlam 2022-02-25 14:30:02 +03:00
parent 9590cdd8d0
commit c631c8c356
1 changed files with 17 additions and 12 deletions
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29
tdutils/td/utils/FlatHashMapLinear.h
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@ -171,6 +171,11 @@ class FlatHashTable {
static constexpr size_t OFFSET = 4 * sizeof(uint32); static constexpr size_t OFFSET = 4 * sizeof(uint32);
static constexpr uint32 INVALID_BUCKET = 0xFFFFFFFF; static constexpr uint32 INVALID_BUCKET = 0xFFFFFFFF;
static inline FlatHashTableInner *get_inner(NodeT *nodes) {
DCHECK(nodes != nullptr);
return reinterpret_cast<FlatHashTableInner *>(reinterpret_cast<char *>(nodes) - OFFSET);
}
static NodeT *allocate_nodes(uint32 size) { static NodeT *allocate_nodes(uint32 size) {
DCHECK(size >= 8); DCHECK(size >= 8);
DCHECK((size & (size - 1)) == 0); DCHECK((size & (size - 1)) == 0);
@ -187,9 +192,9 @@ class FlatHashTable {
return nodes; return nodes;
} }
static void clear_inner(FlatHashTableInner *inner) { static void clear_nodes(NodeT *nodes) {
auto inner = get_inner(nodes);
auto size = inner->bucket_count_; auto size = inner->bucket_count_;
NodeT *nodes = &inner->nodes_[0];
for (uint32 i = 0; i < size; i++) { for (uint32 i = 0; i < size; i++) {
nodes[i].~NodeT(); nodes[i].~NodeT();
} }
@ -197,13 +202,12 @@ class FlatHashTable {
} }
inline FlatHashTableInner *get_inner() { inline FlatHashTableInner *get_inner() {
DCHECK(nodes_ != nullptr); return get_inner(nodes_);
return reinterpret_cast<FlatHashTableInner *>(reinterpret_cast<char *>(nodes_) - OFFSET);
} }
inline const FlatHashTableInner *get_inner() const { inline const FlatHashTableInner *get_inner() const {
DCHECK(nodes_ != nullptr); DCHECK(nodes_ != nullptr);
return reinterpret_cast<const FlatHashTableInner *>(reinterpret_cast<const char *>(nodes_) - OFFSET); return get_inner(const_cast<NodeT *>(nodes_));
} }
inline uint32 &used_node_count() { inline uint32 &used_node_count() {
@ -477,7 +481,7 @@ class FlatHashTable {
void clear() { void clear() {
if (nodes_ != nullptr) { if (nodes_ != nullptr) {
clear_inner(get_inner()); clear_nodes(nodes_);
nodes_ = nullptr; nodes_ = nullptr;
} }
} }
@ -587,17 +591,18 @@ class FlatHashTable {
nodes_ = allocate_nodes(new_size); nodes_ = allocate_nodes(new_size);
used_node_count() = old_size; used_node_count() = old_size;
for (uint32 i = 0; i < old_bucket_count; i++) { auto old_nodes_end = old_nodes + old_bucket_count;
auto &old_node = old_nodes[i]; for (NodeT *old_node = old_nodes; old_node != old_nodes_end; ++old_node) {
if (old_node.empty()) { if (old_node->empty()) {
continue; continue;
} }
auto bucket = calc_bucket(old_node.key()); auto bucket = calc_bucket(old_node->key());
while (!nodes_[bucket].empty()) { while (!nodes_[bucket].empty()) {
next_bucket(bucket); next_bucket(bucket);
} }
nodes_[bucket] = std::move(old_node); nodes_[bucket] = std::move(*old_node);
} }
clear_nodes(old_nodes);
} }
void erase_node(NodeT *it) { void erase_node(NodeT *it) {
@ -608,7 +613,7 @@ class FlatHashTable {
const auto bucket_count = get_bucket_count(); const auto bucket_count = get_bucket_count();
const auto *end = nodes_ + bucket_count; const auto *end = nodes_ + bucket_count;
for (auto *test_node = it + 1; test_node != end; test_node++) { for (auto *test_node = it + 1; test_node != end; test_node++) {
if (test_node->empty()) { if (likely(test_node->empty())) {
return; return;
} }