From c1ce418af29bc1796bfe82a5aa97639eccc30cb7 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Thu, 8 Apr 2021 16:45:25 -0400
Subject: [PATCH] libstdc++: Simplify copy-pasted algorithms in <ranges>
The <ranges> header currently copies some simple algorithms from
<bits/ranges_algo.h>, which was originally done in order to avoid a
circular dependency with the header. This is no longer an issue since
the latter header now includes <bits/ranges_util.h> instead of all of
<ranges>.
This means we could now just include <bits/ranges_algo.h> and remove the
copied algorithms, but that'd increase the size of <ranges> by ~10%.
And we can't use the corresponding STL-style algorithms here because
they assume input iterators are copyable. So this patch instead
simplifies these copied algorithms, removing their constraints and
unused parameters, and keeps them around. In a subsequent patch we're
going to copy (a simplified version of) ranges::find into <ranges> as
well.
libstdc++-v3/ChangeLog:
* include/std/ranges (__detail::find_if): Simplify.
(__detail::find_if_not): Likewise.
(__detail::min): Remove.
(__detail::mismatch): Simplify.
(take_view::size): Use std::min instead of __detail::min.
---
libstdc++-v3/include/std/ranges | 59 ++++++++++-----------------------
1 file changed, 17 insertions(+), 42 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index cfcbcaba0655..9077271e4e6c 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -978,65 +978,40 @@ namespace views::__adaptor
using all_t = decltype(all(std::declval<_Range>()));
} // namespace views
- // XXX: the following algos are copied from ranges_algo.h to avoid a circular
- // dependency with that header.
+ // The following simple algos are transcribed from ranges_algo.h to avoid
+ // having to include that entire header.
namespace __detail
{
- template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
- typename _Proj = identity,
- indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+ template<typename _Iter, typename _Sent, typename _Pred>
constexpr _Iter
- find_if(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {})
+ find_if(_Iter __first, _Sent __last, _Pred __pred)
{
while (__first != __last
- && !(bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
+ && !(bool)std::__invoke(__pred, *__first))
++__first;
return __first;
}
- template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
- typename _Proj = identity,
- indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+ template<typename _Iter, typename _Sent, typename _Pred>
constexpr _Iter
- find_if_not(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {})
+ find_if_not(_Iter __first, _Sent __last, _Pred __pred)
{
while (__first != __last
- && (bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
+ && (bool)std::__invoke(__pred, *__first))
++__first;
return __first;
}
- template<typename _Tp, typename _Proj = identity,
- indirect_strict_weak_order<projected<const _Tp*, _Proj>>
- _Comp = ranges::less>
- constexpr const _Tp&
- min(const _Tp& __a, const _Tp& __b, _Comp __comp = {}, _Proj __proj = {})
- {
- if (std::__invoke(std::move(__comp),
- std::__invoke(__proj, __b),
- std::__invoke(__proj, __a)))
- return __b;
- else
- return __a;
- }
-
- template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
- input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
- typename _Pred = ranges::equal_to,
- typename _Proj1 = identity, typename _Proj2 = identity>
- requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
+ template<typename _Iter1, typename _Sent1, typename _Iter2, typename _Sent2>
constexpr pair<_Iter1, _Iter2>
- mismatch(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
- _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {})
+ mismatch(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2)
{
while (__first1 != __last1 && __first2 != __last2
- && (bool)std::__invoke(__pred,
- std::__invoke(__proj1, *__first1),
- std::__invoke(__proj2, *__first2)))
- {
- ++__first1;
- ++__first2;
- }
+ && (bool)ranges::equal_to{}(*__first1, *__first2))
+ {
+ ++__first1;
+ ++__first2;
+ }
return { std::move(__first1), std::move(__first2) };
}
} // namespace __detail
@@ -1847,14 +1822,14 @@ namespace views::__adaptor
size() requires sized_range<_Vp>
{
auto __n = ranges::size(_M_base);
- return __detail::min(__n, static_cast<decltype(__n)>(_M_count));
+ return std::min(__n, static_cast<decltype(__n)>(_M_count));
}
constexpr auto
size() const requires sized_range<const _Vp>
{
auto __n = ranges::size(_M_base);
- return __detail::min(__n, static_cast<decltype(__n)>(_M_count));
+ return std::min(__n, static_cast<decltype(__n)>(_M_count));
}
};
--
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