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Update rehashing implementation to better reflect STL conformance

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This commit is contained in:
Christian Mazakas
2022-09-01 15:12:06 -07:00
parent 5ad86f559f
commit 9a9b8e0a7b
2 changed files with 24 additions and 9 deletions
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8
include/boost/unordered/detail/fca.hpp
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@ -494,6 +494,14 @@ namespace boost {
group_pointer groups; group_pointer groups;
public: public:
static std::size_t bucket_count_for(std::size_t num_buckets)
{
if (num_buckets == 0) {
return 0;
}
return size_policy::size(size_policy::size_index(num_buckets));
}
grouped_bucket_array() grouped_bucket_array()
: empty_value<node_allocator_type>( : empty_value<node_allocator_type>(
empty_init_t(), node_allocator_type()), empty_init_t(), node_allocator_type()),

25
include/boost/unordered/detail/implementation.hpp
View File

@ -2524,6 +2524,17 @@ namespace boost {
new_buckets.insert_node(itnewb, p); new_buckets.insert_node(itnewb, p);
} }
static std::size_t min_buckets(std::size_t num_elements, float mlf)
{
std::size_t num_buckets = static_cast<std::size_t>(
std::ceil(static_cast<float>(num_elements) / mlf));
if (num_buckets == 0 && num_elements > 0) { // mlf == inf
num_buckets = 1;
}
return num_buckets;
}
void rehash(std::size_t); void rehash(std::size_t);
void reserve(std::size_t); void reserve(std::size_t);
void reserve_for_insert(std::size_t); void reserve_for_insert(std::size_t);
@ -3432,22 +3443,18 @@ namespace boost {
template <typename Types> template <typename Types>
inline void table<Types>::rehash(std::size_t num_buckets) inline void table<Types>::rehash(std::size_t num_buckets)
{ {
std::size_t bc = (std::max)(num_buckets, num_buckets = (std::max)(
static_cast<std::size_t>(1.0f + static_cast<float>(size_) / mlf_)); min_buckets(size_, mlf_), buckets_.bucket_count_for(num_buckets));
if (bc <= buckets_.bucket_count()) { if (num_buckets != this->bucket_count()) {
return; this->rehash_impl(num_buckets);
} }
this->rehash_impl(bc);
} }
template <class Types> template <class Types>
inline void table<Types>::reserve(std::size_t num_elements) inline void table<Types>::reserve(std::size_t num_elements)
{ {
std::size_t const num_buckets = static_cast<std::size_t>( std::size_t num_buckets = min_buckets(num_elements, mlf_);
std::ceil(static_cast<float>(num_elements) / mlf_));
this->rehash(num_buckets); this->rehash(num_buckets);
} }