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P1223R5: find_last, et al. #3268

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merged 11 commits into from
Dec 15, 2022
Merged

P1223R5: find_last, et al. #3268

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576e045
Implement P1223R5 find_last, et al.
SuperWig Dec 6, 2022
b078274
Fix whoopsie daisies
SuperWig Dec 9, 2022
cba7e78
Properly rewrap
SuperWig Dec 9, 2022
03174d6
Utilise _Get_final_iterator_unwrapped
SuperWig Dec 9, 2022
c6282cd
Correct terrible case
SuperWig Dec 10, 2022
938e09e
Add newlines.
StephanTLavavej Dec 13, 2022
8641fb6
This ICE doesn't appear to repro anymore.
StephanTLavavej Dec 13, 2022
20ae24c
Add test coverage for multiple values.
StephanTLavavej Dec 13, 2022
e349138
CR comments
SuperWig Dec 14, 2022
2d59ba0
simplify branching to remove code duplication
CaseyCarter Dec 14, 2022
ec18ebe
switch to `_Search_for`, use `invoke_r`
strega-nil Dec 14, 2022
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135 changes: 36 additions & 99 deletions stl/inc/algorithm
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Original file line number Diff line number Diff line change
Expand Up @@ -2807,13 +2807,12 @@ namespace ranges {
_NODISCARD constexpr subrange<_It> operator()(_It _First, _Se _Last, const _Ty& _Value, _Pj _Proj = {}) const {
_Adl_verify_range(_First, _Last);

auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
if constexpr (bidirectional_iterator<_It>) {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Get_final_iterator_unwrapped<_It>(_UFirst, _STD move(_Last));
auto _UResult = _Find_last_unchecked(_STD move(_UFirst), _STD move(_ULast), _Value, _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
} else {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Unwrap_sent<_It>(_STD move(_Last));
auto _UResult = _Find_last_unchecked(_STD move(_UFirst), _STD move(_ULast), _Value, _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
Expand Down Expand Up @@ -2858,8 +2857,8 @@ namespace ranges {
}
return {_STD move(_Result), _STD move(_Last)};
} else {
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_It _Result = _First;
bool _Found = false;
auto _Result = _First;
bool _Found = false;
for (;; ++_First) {
if (_First == _Last) {
if (!_Found) {
Expand All @@ -2880,6 +2879,7 @@ namespace ranges {

_EXPORT_STD inline constexpr _Find_last_fn find_last{_Not_quite_object::_Construct_tag{}};

template <bool _If_not>
class _Find_last_if_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;
Expand All @@ -2889,20 +2889,20 @@ namespace ranges {
_NODISCARD constexpr subrange<_It> operator()(_It _First, _Se _Last, _Pr _Pred, _Pj _Proj = {}) const {
_Adl_verify_range(_First, _Last);

auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
if constexpr (bidirectional_iterator<_It>) {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Get_final_iterator_unwrapped<_It>(_UFirst, _STD move(_Last));
auto _ULast = _Get_final_iterator_unwrapped<_It>(_UFirst, _STD move(_Last));
auto _UResult =
_Find_last_if_unchecked(_STD move(_UFirst), _STD move(_ULast), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
} else {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Unwrap_sent<_It>(_STD move(_Last));
auto _ULast = _Unwrap_sent<_It>(_STD move(_Last));
auto _UResult =
_Find_last_if_unchecked(_STD move(_UFirst), _STD move(_ULast), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
}
}

template <forward_range _Rng, class _Pj = identity,
indirect_unary_predicate<projected<iterator_t<_Rng>, _Pj>> _Pr>
_NODISCARD constexpr borrowed_subrange_t<_Rng> operator()(_Rng&& _Range, _Pr _Pred, _Pj _Proj = {}) const {
Expand All @@ -2926,105 +2926,34 @@ namespace ranges {

if constexpr (_Bidi_common<_It, _Se>) {
for (auto _Result = _Last; _Result != _First;) {
if (_STD invoke(_Pred, _STD invoke(_Proj, *--_Result))) {
return {_STD move(_Result), _STD move(_Last)};
if constexpr (_If_not) {
if (!_STD invoke(_Pred, _STD invoke(_Proj, *--_Result))) {
return {_STD move(_Result), _STD move(_Last)};
}
} else {
if (_STD invoke(_Pred, _STD invoke(_Proj, *--_Result))) {
return {_STD move(_Result), _STD move(_Last)};
}
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}
}
return {_Last, _Last};
} else if constexpr (same_as<_It, _Se>) {
auto _Result = _Last;
for (; _First != _Last; ++_First) {
if (_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
}
}
return {_STD move(_Result), _STD move(_Last)};
} else {
_It _Result = _First;
bool _Found = false;
for (;; ++_First) {
if (_First == _Last) {
if (!_Found) {
if constexpr (_If_not) {
if (!_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
}
} else {
if (_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
}
break;
}

if (_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
_Found = true;
}
}
return {_STD move(_Result), _STD move(_First)};
}
}
};

_EXPORT_STD inline constexpr _Find_last_if_fn find_last_if{_Not_quite_object::_Construct_tag{}};

class _Find_last_if_not_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;

template <forward_iterator _It, sentinel_for<_It> _Se, class _Pj = identity,
indirect_unary_predicate<projected<_It, _Pj>> _Pr>
_NODISCARD constexpr subrange<_It> operator()(_It _First, _Se _Last, _Pr _Pred, _Pj _Proj = {}) const {
_Adl_verify_range(_First, _Last);

if constexpr (bidirectional_iterator<_It>) {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Get_final_iterator_unwrapped<_It>(_UFirst, _STD move(_Last));
auto _UResult = _Find_last_if_not_unchecked(
_STD move(_UFirst), _STD move(_ULast), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
} else {
auto _UFirst = _Unwrap_iter<_Se>(_STD move(_First));
auto _ULast = _Unwrap_sent<_It>(_STD move(_Last));
auto _UResult = _Find_last_if_not_unchecked(
_STD move(_UFirst), _STD move(_ULast), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<subrange<_It>>(_First, _STD move(_UResult));
}
}
template <forward_range _Rng, class _Pj = identity,
indirect_unary_predicate<projected<iterator_t<_Rng>, _Pj>> _Pr>
_NODISCARD constexpr borrowed_subrange_t<_Rng> operator()(_Rng&& _Range, _Pr _Pred, _Pj _Proj = {}) const {
if constexpr (bidirectional_range<_Rng>) {
auto _UResult = _Find_last_if_not_unchecked(
_Ubegin(_Range), _Get_final_iterator_unwrapped(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<borrowed_subrange_t<_Rng>>(_Range, _STD move(_UResult));
} else {
auto _UResult =
_Find_last_if_not_unchecked(_Ubegin(_Range), _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
return _Rewrap_subrange<borrowed_subrange_t<_Rng>>(_Range, _STD move(_UResult));
}
}

private:
template <class _It, class _Se, class _Pj, class _Pr>
_NODISCARD static constexpr subrange<_It> _Find_last_if_not_unchecked(
_It _First, _Se _Last, _Pr _Pred, _Pj _Proj) {
_STL_INTERNAL_STATIC_ASSERT(forward_iterator<_It>);
_STL_INTERNAL_STATIC_ASSERT(sentinel_for<_Se, _It>);
_STL_INTERNAL_STATIC_ASSERT(indirect_unary_predicate<_Pr, projected<_It, _Pj>>);

if constexpr (_Bidi_common<_It, _Se>) {
for (auto _Result = _Last; _Result != _First;) {
if (!_STD invoke(_Pred, _STD invoke(_Proj, *--_Result))) {
return {_STD move(_Result), _STD move(_Last)};
}
}
return {_Last, _Last};
} else if constexpr (same_as<_It, _Se>) {
auto _Result = _Last;
for (; _First != _Last; ++_First) {
if (!_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
}
}
return {_STD move(_Result), _STD move(_Last)};
} else {
_It _Result = _First;
bool _Found = false;
auto _Result = _First;
bool _Found = false;
for (;; ++_First) {
if (_First == _Last) {
if (!_Found) {
Expand All @@ -3033,17 +2962,25 @@ namespace ranges {
break;
}

if (!_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
_Found = true;
if constexpr (_If_not) {
if (!_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
_Found = true;
}
} else {
if (_STD invoke(_Pred, _STD invoke(_Proj, *_First))) {
_Result = _First;
_Found = true;
}
}
}
return {_STD move(_Result), _STD move(_First)};
}
}
};

_EXPORT_STD inline constexpr _Find_last_if_not_fn find_last_if_not{_Not_quite_object::_Construct_tag{}};
_EXPORT_STD inline constexpr _Find_last_if_fn<false> find_last_if{_Not_quite_object::_Construct_tag{}};
_EXPORT_STD inline constexpr _Find_last_if_fn<true> find_last_if_not{_Not_quite_object::_Construct_tag{}};
#endif // _HAS_CXX23
} // namespace ranges
#endif // __cpp_lib_concepts
Expand Down
9 changes: 3 additions & 6 deletions tests/std/tests/P1223R5_ranges_alg_find_last/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@

#include <algorithm>
#include <cassert>
#include <concepts>
#include <ranges>
#include <span>
#include <utility>
Expand Down Expand Up @@ -38,15 +37,13 @@ struct instantiator {
{ // Validate range overload [found case]
Read wrapped_input{haystack};
const auto result = find_last(wrapped_input, value, get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
{ // Validate iterator + sentinel overload [found case]
Read wrapped_input{haystack};
auto result = find_last(wrapped_input.begin(), wrapped_input.end(), value, get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
const auto result = find_last(wrapped_input.begin(), wrapped_input.end(), value, get_first);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
}
Expand Down
11 changes: 4 additions & 7 deletions tests/std/tests/P1223R5_ranges_alg_find_last_if/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@

#include <algorithm>
#include <cassert>
#include <concepts>
#include <ranges>
#include <span>
#include <utility>
Expand Down Expand Up @@ -40,16 +39,14 @@ struct instantiator {
for (const auto& [value, _] : haystack) {
{ // Validate range overload [found case]
Read wrapped_input{haystack};
auto result = find_last_if(wrapped_input, equals(value), get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
const auto result = find_last_if(wrapped_input, equals(value), get_first);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
{ // Validate iterator + sentinel overload [found case]
Read wrapped_input{haystack};
auto result = find_last_if(wrapped_input.begin(), wrapped_input.end(), equals(value), get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
const auto result = find_last_if(wrapped_input.begin(), wrapped_input.end(), equals(value), get_first);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
}
Expand Down
11 changes: 4 additions & 7 deletions tests/std/tests/P1223R5_ranges_alg_find_last_if_not/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@

#include <algorithm>
#include <cassert>
#include <concepts>
#include <ranges>
#include <span>
#include <utility>
Expand Down Expand Up @@ -40,17 +39,15 @@ struct instantiator {
for (const auto& [value, _] : haystack) {
{ // Validate range overload [found case]
Read wrapped_input{haystack};
auto result = find_last_if_not(wrapped_input, not_equals(value), get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
const auto result = find_last_if_not(wrapped_input, not_equals(value), get_first);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
{ // Validate iterator + sentinel overload [found case]
Read wrapped_input{haystack};
auto result =
const auto result =
find_last_if_not(wrapped_input.begin(), wrapped_input.end(), not_equals(value), get_first);
STATIC_ASSERT(same_as<iterator_t<decltype(result)>, iterator_t<Read>>);
STATIC_ASSERT(common_range<decltype(result)>);
STATIC_ASSERT(same_as<decltype(result), const ranges::subrange<iterator_t<Read>>>);
check_value(result.front(), value);
}
}
Expand Down