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Vectorize basic_string::find #5101

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Vectorize basic_string::find #5101

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95d3776
Vectorize `basic_string::find`
AlexGuteniev Nov 19, 2024
97b4cfa
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AlexGuteniev Nov 19, 2024
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25 changes: 21 additions & 4 deletions stl/inc/__msvc_string_view.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -660,12 +660,29 @@ template <class _Traits>
constexpr size_t _Traits_find_ch(_In_reads_(_Hay_size) const _Traits_ptr_t<_Traits> _Haystack, const size_t _Hay_size,
const size_t _Start_at, const _Traits_ch_t<_Traits> _Ch) noexcept {
// search [_Haystack, _Haystack + _Hay_size) for _Ch, at/after _Start_at
if (_Start_at < _Hay_size) {
const auto _Found_at = _Traits::find(_Haystack + _Start_at, _Hay_size - _Start_at, _Ch);
if (_Found_at) {
return static_cast<size_t>(_Found_at - _Haystack);
if (_Start_at >= _Hay_size) {
return static_cast<size_t>(-1); // (npos) no room for match
}

#if _USE_STD_VECTOR_ALGORITHMS
if constexpr (_Is_implementation_handled_char_traits<_Traits>) {
if (!_STD _Is_constant_evaluated()) {
const auto _End = _Haystack + _Hay_size;
const auto _Ptr = _STD _Find_vectorized(_Haystack + _Start_at, _End, _Ch);

if (_Ptr != _End) {
return static_cast<size_t>(_Ptr - _Haystack);
} else {
return static_cast<size_t>(-1); // (npos) no match
}
}
}
#endif // _USE_STD_VECTOR_ALGORITHMS

const auto _Found_at = _Traits::find(_Haystack + _Start_at, _Hay_size - _Start_at, _Ch);
if (_Found_at) {
return static_cast<size_t>(_Found_at - _Haystack);
}

return static_cast<size_t>(-1); // (npos) no match
}
Expand Down
53 changes: 36 additions & 17 deletions tests/std/tests/VSO_0000000_vector_algorithms/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1090,6 +1090,38 @@ void test_case_string_find_last_of(const basic_string<T>& input_haystack, const
assert(expected == actual);
}

template <class T>
void test_case_string_find_ch(const basic_string<T>& input_haystack, const T value) {
ptrdiff_t expected;

const auto expected_iter = last_known_good_find(input_haystack.begin(), input_haystack.end(), value);

if (expected_iter != input_haystack.end()) {
expected = expected_iter - input_haystack.begin();
} else {
expected = -1;
}

const auto actual = static_cast<ptrdiff_t>(input_haystack.find(value));
assert(expected == actual);
}

template <class T>
void test_case_string_rfind_ch(const basic_string<T>& input_haystack, const T value) {
ptrdiff_t expected;

const auto expected_iter = last_known_good_find_last(input_haystack.begin(), input_haystack.end(), value);

if (expected_iter != input_haystack.end()) {
expected = expected_iter - input_haystack.begin();
} else {
expected = -1;
}

const auto actual = static_cast<ptrdiff_t>(input_haystack.rfind(value));
assert(expected == actual);
}

template <class T>
void test_case_string_find_str(const basic_string<T>& input_haystack, const basic_string<T>& input_needle) {
ptrdiff_t expected;
Expand Down Expand Up @@ -1128,22 +1160,6 @@ void test_case_string_rfind_str(const basic_string<T>& input_haystack, const bas
assert(expected == actual);
}

template <class T>
void test_case_string_rfind_ch(const basic_string<T>& input_haystack, const T value) {
ptrdiff_t expected;

const auto expected_iter = last_known_good_find_last(input_haystack.begin(), input_haystack.end(), value);

if (expected_iter != input_haystack.end()) {
expected = expected_iter - input_haystack.begin();
} else {
expected = -1;
}

const auto actual = static_cast<ptrdiff_t>(input_haystack.rfind(value));
assert(expected == actual);
}

template <class T, class D>
void test_basic_string_dis(mt19937_64& gen, D& dis) {
basic_string<T> input_haystack;
Expand All @@ -1154,13 +1170,16 @@ void test_basic_string_dis(mt19937_64& gen, D& dis) {
temp.reserve(needleDataCount);

for (;;) {
const auto input_element = static_cast<T>(dis(gen));
test_case_string_find_ch(input_haystack, input_element);
test_case_string_rfind_ch(input_haystack, input_element);

input_needle.clear();

test_case_string_find_first_of(input_haystack, input_needle);
test_case_string_find_last_of(input_haystack, input_needle);
test_case_string_find_str(input_haystack, input_needle);
test_case_string_rfind_str(input_haystack, input_needle);
test_case_string_rfind_ch(input_haystack, static_cast<T>(dis(gen)));

for (size_t attempts = 0; attempts < needleDataCount; ++attempts) {
input_needle.push_back(static_cast<T>(dis(gen)));
Expand Down