AuroraMiddleware/qt5base-lts
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Sequential containers: make removeIf/erase_if not detach unless needed

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Employ the same kind of optimization existing for removeAll/erase.

Change-Id: I0781cc02d4430ceab60e6e50a5ffe6fde87be9ce
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Giuseppe D'Angelo 2020-12-04 16:05:58 +01:00
parent 9ae0e21131
commit a3e5efa8a2
1 changed files with 10 additions and 2 deletions
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12
src/corelib/tools/qcontainertools_impl.h
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@ -191,9 +191,17 @@ auto sequential_erase_one(Container &c, const T &t)
template <typename Container, typename Predicate>
auto sequential_erase_if(Container &c, Predicate &pred)
{
// avoid a detach in case there is nothing to remove
const auto cbegin = c.cbegin();
const auto cend = c.cend();
const auto t_it = std::find_if(cbegin, cend, pred);
auto result = std::distance(cbegin, t_it);
if (result == c.size())
return result - result; // `0` of the right type
const auto e = c.end();
const auto it = std::remove_if(c.begin(), e, pred);
const auto result = std::distance(it, e);
const auto it = std::remove_if(std::next(c.begin(), result), e, pred);
result = std::distance(it, e);
c.erase(it, e);
return result;
}