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Avoid an unnecessary copy in 'operator[]'

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[SVN r52224]
This commit is contained in:
Daniel James
2009-04-06 22:51:36 +00:00
parent 290c7566ff
commit 4ac0a12a83
1 changed files with 17 additions and 1 deletions
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18
include/boost/unordered/detail/hash_table_impl.hpp
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@ -215,6 +215,22 @@ namespace boost {
} }
#endif #endif
template <typename K, typename M>
void construct_pair(K const& k, M*)
{
BOOST_ASSERT(!node_);
node_constructed_ = false;
value_constructed_ = false;
node_ = allocators_.node_alloc_.allocate(1);
allocators_.node_alloc_.construct(node_, node());
node_constructed_ = true;
new(node_->address()) value_type(k, M());
value_constructed_ = true;
}
node_ptr get() const node_ptr get() const
{ {
BOOST_ASSERT(node_); BOOST_ASSERT(node_);
@ -1757,7 +1773,7 @@ namespace boost {
// Create the node before rehashing in case it throws an // Create the node before rehashing in case it throws an
// exception (need strong safety in such a case). // exception (need strong safety in such a case).
node_constructor a(data_.allocators_); node_constructor a(data_.allocators_);
a.construct(value_type(k, mapped_type())); a.construct_pair(k, (mapped_type*) 0);
// reserve has basic exception safety if the hash function // reserve has basic exception safety if the hash function
// throws, strong otherwise. // throws, strong otherwise.