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<xhash>: Get rid of tricks for transparent overloads of hash containers #5208

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<xhash>: Get rid of tricks for transparent overloads of hash containers #5208

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318ba54
Get rid of tricks for transparent overloads of hash containers
frederick-vs-ja Dec 27, 2024
8d4a2c2
Merge branch 'main' into transparent-hash-containers-no-trick
StephanTLavavej Jan 7, 2025
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7 changes: 4 additions & 3 deletions stl/inc/hash_map
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Original file line number Diff line number Diff line change
Expand Up @@ -54,9 +54,10 @@ namespace stdext {

template <class... _Args>
using _In_place_key_extractor = _STD _In_place_key_extract_map<_Kty, _Args...>;
template <class>
using _Deduce_key = const _Kty&;
using key_equal = _Tr;

using key_equal = _Tr;

static constexpr bool _Has_transparent_overloads = false;

#if _HAS_CXX20 && defined(__EDG__) // TRANSITION, DevCom-10678753
template <class, class>
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7 changes: 4 additions & 3 deletions stl/inc/hash_set
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Expand Up @@ -49,9 +49,10 @@ namespace stdext {

template <class... _Args>
using _In_place_key_extractor = _STD _In_place_key_extract_set<_Kty, _Args...>;
template <class>
using _Deduce_key = const _Kty&;
using key_equal = _Tr;

using key_equal = _Tr;

static constexpr bool _Has_transparent_overloads = false;

#if _HAS_CXX20 && defined(__EDG__) // TRANSITION, DevCom-10678753
template <class, class>
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78 changes: 61 additions & 17 deletions stl/inc/xhash
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Expand Up @@ -96,8 +96,7 @@ _STD_BEGIN
template <class _Kty, class _Hasher, class _Keyeq>
struct _Uhash_choose_transparency {
// transparency selector for non-transparent hashed containers
template <class>
using _Deduce_key = const _Kty&;
static constexpr bool _Has_transparent_overloads = false;

#if _HAS_CXX20 && defined(__EDG__) // TRANSITION, DevCom-10678753
template <class, class>
Expand All @@ -110,8 +109,7 @@ template <class _Kty, class _Hasher, class _Keyeq>
requires _Is_transparent_v<_Hasher> && _Is_transparent_v<_Keyeq>
struct _Uhash_choose_transparency<_Kty, _Hasher, _Keyeq> {
// transparency selector for transparent hashed containers
template <class _Keyty>
using _Deduce_key = const _Keyty&;
static constexpr bool _Has_transparent_overloads = true;

template <class _Container, class _Kx>
static constexpr bool _Supports_transparency =
Expand Down Expand Up @@ -1225,25 +1223,43 @@ private:
}

public:
template <class _Keyty = void>
_NODISCARD iterator find(typename _Traits::template _Deduce_key<_Keyty> _Keyval) {
_NODISCARD iterator find(const key_type& _Keyval) {
return _List._Make_iter(_Find(_Keyval, _Traitsobj(_Keyval)));
}

#if _HAS_CXX20
template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD iterator find(const _KeyTy& _Keyval) {
return _List._Make_iter(_Find(_Keyval, _Traitsobj(_Keyval)));
}
#endif // _HAS_CXX20

template <class _Keyty = void>
_NODISCARD const_iterator find(typename _Traits::template _Deduce_key<_Keyty> _Keyval) const {
_NODISCARD const_iterator find(const key_type& _Keyval) const {
return _List._Make_const_iter(_Find(_Keyval, _Traitsobj(_Keyval)));
}

#if _HAS_CXX20
template <class _Keyty = void>
_NODISCARD bool contains(_Traits::template _Deduce_key<_Keyty> _Keyval) const {
template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD const_iterator find(const _KeyTy& _Keyval) const {
return _List._Make_const_iter(_Find(_Keyval, _Traitsobj(_Keyval)));
}
#endif // _HAS_CXX20

#if _HAS_CXX20
_NODISCARD bool contains(const key_type& _Keyval) const {
return static_cast<bool>(_Find_last(_Keyval, _Traitsobj(_Keyval))._Duplicate);
}

template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD bool contains(const _KeyTy& _Keyval) const {
return static_cast<bool>(_Find_last(_Keyval, _Traitsobj(_Keyval))._Duplicate);
}
#endif // _HAS_CXX20

template <class _Keyty = void>
_NODISCARD size_type count(typename _Traits::template _Deduce_key<_Keyty> _Keyval) const {
_NODISCARD size_type count(const key_type& _Keyval) const {
const size_t _Hashval = _Traitsobj(_Keyval);
if constexpr (_Multi) {
return _Equal_range(_Keyval, _Hashval)._Distance;
Expand All @@ -1252,6 +1268,19 @@ public:
}
}

#if _HAS_CXX20
template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD size_type count(const _KeyTy& _Keyval) const {
const size_t _Hashval = _Traitsobj(_Keyval);
if constexpr (_Multi) {
return _Equal_range(_Keyval, _Hashval)._Distance;
} else {
return static_cast<bool>(_Find_last(_Keyval, _Hashval)._Duplicate);
}
}
#endif // _HAS_CXX20

private:
struct _Equal_range_result {
_Unchecked_const_iterator _First;
Expand Down Expand Up @@ -1307,19 +1336,34 @@ private:
}

public:
template <class _Keyty = void>
_NODISCARD pair<iterator, iterator> equal_range(typename _Traits::template _Deduce_key<_Keyty> _Keyval) {
_NODISCARD pair<iterator, iterator> equal_range(const key_type& _Keyval) {
const auto _Result = _Equal_range(_Keyval, _Traitsobj(_Keyval));
return {_List._Make_iter(_Result._First._Ptr), _List._Make_iter(_Result._Last._Ptr)};
}

#if _HAS_CXX20
template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD pair<iterator, iterator> equal_range(const _KeyTy& _Keyval) {
const auto _Result = _Equal_range(_Keyval, _Traitsobj(_Keyval));
return {_List._Make_iter(_Result._First._Ptr), _List._Make_iter(_Result._Last._Ptr)};
}
#endif // _HAS_CXX20

template <class _Keyty = void>
_NODISCARD pair<const_iterator, const_iterator> equal_range(
typename _Traits::template _Deduce_key<_Keyty> _Keyval) const {
_NODISCARD pair<const_iterator, const_iterator> equal_range(const key_type& _Keyval) const {
const auto _Result = _Equal_range(_Keyval, _Traitsobj(_Keyval));
return {_List._Make_const_iter(_Result._First._Ptr), _List._Make_const_iter(_Result._Last._Ptr)};
}

#if _HAS_CXX20
template <class _KeyTy>
requires _Traits::_Has_transparent_overloads
_NODISCARD pair<const_iterator, const_iterator> equal_range(const _KeyTy& _Keyval) const {
const auto _Result = _Equal_range(_Keyval, _Traitsobj(_Keyval));
return {_List._Make_const_iter(_Result._First._Ptr), _List._Make_const_iter(_Result._Last._Ptr)};
}
#endif // _HAS_CXX20

void swap(_Hash& _Right) noexcept(noexcept(_Traitsobj.swap(_Right._Traitsobj))) /* strengthened */ {
if (this != _STD addressof(_Right)) {
_Traitsobj.swap(_Right._Traitsobj);
Expand Down
30 changes: 30 additions & 0 deletions tests/std/tests/P0919R3_heterogeneous_unordered_lookup/test.cpp
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Expand Up @@ -272,6 +272,9 @@ void assert_unique() {
emplace_test_strings(cRawToExtract);
#endif // _HAS_CXX23

// GH-5207 "<xhash>: Some member functions of transparent hash containers fail to work with initializer lists"
typename Container::key_type testNotInStringListSrc(testNotInString.data(), testNotInString.size());

// Test that transparent containers pass through the string_view; non-transparent containers
// are only passed in here with string_view value_type, so they also don't allocate.
[[maybe_unused]] prohibit_allocations prohibitor(true);
Expand All @@ -281,6 +284,18 @@ void assert_unique() {
assert(c.count(testNotInString) == 0);
assert_range_empty(c.equal_range(testNotInString));

assert(c.find({testNotInStringListSrc}) == c.end());
assert(c.contains({testNotInStringListSrc}) == false);
assert(c.count({testNotInStringListSrc}) == 0);
assert_range_empty(c.equal_range({testNotInStringListSrc}));

// Test non-const overloads.
assert(cRaw.find(testNotInString) == cRaw.end());
assert_range_empty(cRaw.equal_range(testNotInString));

assert(cRaw.find({testNotInStringListSrc}) == cRaw.end());
assert_range_empty(cRaw.equal_range({testNotInStringListSrc}));

for (const auto& example : testStrings) {
const auto target = c.find(example);
assert(target != c.end());
Expand Down Expand Up @@ -328,6 +343,9 @@ void assert_multi() {
#endif // _HAS_CXX23
}

// GH-5207 "<xhash>: Some member functions of transparent hash containers fail to work with initializer lists"
typename Container::key_type testNotInStringListSrc(testNotInString.data(), testNotInString.size());

// Test that transparent containers pass through the string_view; non-transparent containers
// are only passed in here with string_view value_type, so they also don't allocate.
[[maybe_unused]] prohibit_allocations prohibitor(true);
Expand All @@ -337,6 +355,18 @@ void assert_multi() {
assert(c.count(testNotInString) == 0);
assert_range_empty(c.equal_range(testNotInString));

assert(c.find({testNotInStringListSrc}) == c.end());
assert(c.contains({testNotInStringListSrc}) == false);
assert(c.count({testNotInStringListSrc}) == 0);
assert_range_empty(c.equal_range({testNotInStringListSrc}));

// Test non-const overloads.
assert(cRaw.find(testNotInString) == cRaw.end());
assert_range_empty(cRaw.equal_range(testNotInString));

assert(cRaw.find({testNotInStringListSrc}) == cRaw.end());
assert_range_empty(cRaw.equal_range({testNotInStringListSrc}));

for (const auto& example : testStrings) {
const auto target = c.find(example);
assert(target != c.end());
Expand Down