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Performance improvement: (#79)

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Performance improvement: Add move semantics to by-value parameters (iterator and predicate), to eliminate the cost of copy-construction. Both the Predicate (Normally a std::function, or lambda), and custom iterators can have state, which can be expensive to copy. Profiler identified this as a bottleneck while using boost::adaptors::filtered.
This commit is contained in:
Brian Weed
2023-06-22 14:06:19 -04:00
committed by GitHub
parent 6d02c36718
commit d11499c08c
1 changed files with 14 additions and 4 deletions
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18
include/boost/iterator/filter_iterator.hpp
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@ -12,6 +12,14 @@
#include <boost/type_traits/is_class.hpp>
#include <boost/static_assert.hpp>
#include <boost/config.hpp>
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
#include <utility>
#define BOOST_ITERATOR_DETAIL_MOVE(x) std::move(x)
#else
#define BOOST_ITERATOR_DETAIL_MOVE(x) x
#endif
namespace boost {
namespace iterators {
@ -54,13 +62,13 @@ namespace iterators {
filter_iterator() { }
filter_iterator(Predicate f, Iterator x, Iterator end_ = Iterator())
: super_t(x), m_predicate(f), m_end(end_)
: super_t(BOOST_ITERATOR_DETAIL_MOVE(x)), m_predicate(BOOST_ITERATOR_DETAIL_MOVE(f)), m_end(BOOST_ITERATOR_DETAIL_MOVE(end_))
{
satisfy_predicate();
}
filter_iterator(Iterator x, Iterator end_ = Iterator())
: super_t(x), m_predicate(), m_end(end_)
: super_t(BOOST_ITERATOR_DETAIL_MOVE(x)), m_predicate(), m_end(BOOST_ITERATOR_DETAIL_MOVE(end_))
{
// Pro8 is a little too aggressive about instantiating the
// body of this function.
@ -111,7 +119,7 @@ namespace iterators {
inline filter_iterator<Predicate,Iterator>
make_filter_iterator(Predicate f, Iterator x, Iterator end = Iterator())
{
return filter_iterator<Predicate,Iterator>(f,x,end);
return filter_iterator<Predicate,Iterator>(BOOST_ITERATOR_DETAIL_MOVE(f),BOOST_ITERATOR_DETAIL_MOVE(x),BOOST_ITERATOR_DETAIL_MOVE(end));
}
template <class Predicate, class Iterator>
@ -123,7 +131,7 @@ namespace iterators {
>::type x
, Iterator end = Iterator())
{
return filter_iterator<Predicate,Iterator>(x,end);
return filter_iterator<Predicate,Iterator>(BOOST_ITERATOR_DETAIL_MOVE(x),BOOST_ITERATOR_DETAIL_MOVE(end));
}
} // namespace iterators
@ -133,4 +141,6 @@ using iterators::make_filter_iterator;
} // namespace boost
#undef BOOST_ITERATOR_DETAIL_MOVE
#endif // BOOST_FILTER_ITERATOR_23022003THW_HPP