<regex>: regex_traits::transform_primary should yield primary sort keys appropriate for the imbued locale

stl/CMakeLists.txt

@@ -213,6 +213,7 @@ set(IMPLIB_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/locale0_implib.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/nothrow.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/print.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/regex.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/sharedmutex.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/stacktrace.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/syserror_import_lib.cpp

stl/inc/locale

@@ -94,6 +94,9 @@ inline size_t __CRTDECL _LStrxfrm(_Out_writes_(_Last1 - _First1) _Post_readable_
 }
 #endif // defined(_CRTBLD)
 
+template <class _Elem>
+class _Regex_traits;
+
 _EXPORT_STD template <class _Elem>
 class collate : public locale::facet { // facet for ordering sequences of elements
 public:
@@ -189,6 +192,8 @@ protected:
 
 private:
     _Locinfo::_Collvec _Coll; // used by _LStrcoll and _XStrxfrm
+
+    friend _Regex_traits<_Elem>;
 };
 
 #ifdef __clang__

stl/inc/regex

@@ -53,6 +53,17 @@ _STL_DISABLE_CLANG_WARNINGS
 #endif // ^^^ !defined(_DEBUG) ^^^
 #endif // !defined(_ENHANCED_REGEX_VISUALIZER)
 
+#ifdef _CPPRTTI
+extern "C" {
+_STD size_t __stdcall __std_regex_transform_primary_char(
+    _Out_writes_(_Last1 - _First1) _Post_readable_size_(return) char* _First1, char* _Last1,
+    _In_reads_(_Last2 - _First2) const char* _First2, const char* _Last2, _In_opt_ const _Collvec*) noexcept;
+_STD size_t __stdcall __std_regex_transform_primary_wchar_t(
+    _Out_writes_(_Last1 - _First1) _Post_readable_size_(return) wchar_t* _First1, wchar_t* _Last1,
+    _In_reads_(_Last2 - _First2) const wchar_t* _First2, const wchar_t* _Last2, _In_opt_ const _Collvec*) noexcept;
+} // extern "C"
+#endif // ^^^ defined(_CPPRTTI) ^^^
+
 _STD_BEGIN
 
 enum _Meta_type : int { // meta character representations for parser
@@ -267,6 +278,20 @@ struct _Regex_traits_base { // base of all regular expression traits
     using char_class_type = ctype_base::mask;
 };
 
+#ifdef _CPPRTTI
+inline size_t _Regex_transform_primary(_Out_writes_(_Last1 - _First1) _Post_readable_size_(return) char* _First1,
+    char* _Last1, _In_reads_(_Last2 - _First2) const char* _First2, const char* _Last2,
+    _In_opt_ const _Locinfo::_Collvec* _Vector) noexcept {
+    return __std_regex_transform_primary_char(_First1, _Last1, _First2, _Last2, _Vector);
+}
+
+inline size_t _Regex_transform_primary(_Out_writes_(_Last1 - _First1) _Post_readable_size_(return) wchar_t* _First1,
+    wchar_t* _Last1, _In_reads_(_Last2 - _First2) const wchar_t* _First2, const wchar_t* _Last2,
+    _In_opt_ const _Locinfo::_Collvec* _Vector) noexcept {
+    return __std_regex_transform_primary_wchar_t(_First1, _Last1, _First2, _Last2, _Vector);
+}
+#endif // ^^^ defined(_CPPRTTI) ^^^
+
 template <class _Elem>
 class _Regex_traits : public _Regex_traits_base { // base class for regular expression traits
 public:
@@ -312,13 +337,38 @@ public:
     string_type transform_primary(_FwdIt _First, _FwdIt _Last) const {
         // apply locale-specific case-insensitive transformation
         string_type _Res;
-
-        if (_First != _Last) { // non-empty string, transform it
-            vector<_Elem> _Temp(_First, _Last);
-
-            _Getctype()->tolower(_Temp.data(), _Temp.data() + _Temp.size());
-            _Res = _Getcoll()->transform(_Temp.data(), _Temp.data() + _Temp.size());
+#ifdef _CPPRTTI
+        if (_First != _Last) {
+            const collate<_Elem>* _Coll = _Getcoll();
+            const auto& _Coll_type      = typeid(*_Coll);
+            // TRANSITION, ABI: GH-5394: locale creates collate objects of type collate, not collate_byname.
+            // Depending on the resolution of LWG-2338, comparison to typeid(collate) might also become
+            // required by the standard.
+            if (_Coll_type == typeid(collate_byname<_Elem>) || _Coll_type == typeid(collate<_Elem>)) {
+                // non-empty string with known collate facet, transform it
+                const string_type _Src(_First, _Last);
+                const auto _Src_first = _Src.data();
+                const auto _Src_last  = _Src_first + _Src.size();
+
+                size_t _Count = _Src.size();
+                while (_Res.size() < _Count) {
+                    _Res.resize(_Count);
+                    _Count = _STD _Regex_transform_primary(
+                        &_Res[0], &_Res[0] + _Count, _Src_first, _Src_last, &_Coll->_Coll);
+
+                    if (_Count == static_cast<size_t>(-1)) {
+                        // return empty string in case of error
+                        _Count = 0;
+                        break;
+                    }
+                }
+                _Res.resize(_Count);
+            }
         }
+#else // ^^^ defined(_CPPRTTI) / !defined(_CPPRTTI) vvv
+        (void) _First;
+        (void) _Last;
+#endif // ^^^ !defined(_CPPRTTI) ^^^
         return _Res;
     }
 
@@ -4181,26 +4231,30 @@ _Prs_ret _Parser<_FwdIt, _Elem, _RxTraits>::_Do_ex_class2(
 
         _Elem* const _Coll_elem_first      = &_Coll_elem.front();
         const _Elem* const _Coll_elem_last = _Coll_elem_first + _Size;
+
+        if (_Size == 1 && _End_arg == _Meta_dot) {
+            // process single-element collating elements like individual characters
+            _Val = *_Coll_elem_first;
+            return _Prs_chr;
+        }
+
+        if (_Flags & regex_constants::icase) {
+            for (auto _Current = _Coll_elem_first; _Current != _Coll_elem_last; ++_Current) {
+                *_Current = _Traits.translate_nocase(*_Current);
+            }
+        } else if (_Flags & regex_constants::collate) {
+            for (auto _Current = _Coll_elem_first; _Current != _Coll_elem_last; ++_Current) {
+                *_Current = _Traits.translate(*_Current);
+            }
+        }
+
         if (_End_arg == _Meta_equal) { // process equivalence
             _Nfa._Add_equiv2(_Coll_elem_first, _Coll_elem_last);
             return _Prs_set;
         } else { // process collating element
-            if (_Size == 1) {
-                _Val = *_Coll_elem_first;
-                return _Prs_chr;
-            }
 
             // Character ranges with multi-character bounds cannot be represented in NFA nodes yet (see GH-5391).
             // Provisionally treat multi-character collating elements as character sets.
-            if (_Flags & regex_constants::icase) {
-                for (auto _Current = _Coll_elem_first; _Current != _Coll_elem_last; ++_Current) {
-                    *_Current = _Traits.translate_nocase(*_Current);
-                }
-            } else if (_Flags & regex_constants::collate) {
-                for (auto _Current = _Coll_elem_first; _Current != _Coll_elem_last; ++_Current) {
-                    *_Current = _Traits.translate(*_Current);
-                }
-            }
             _Nfa._Add_coll2(_Coll_elem_first, _Coll_elem_last);
             return _Prs_set;
         }

stl/inc/yvals.h

@@ -3,7 +3,8 @@
 // Copyright (c) Microsoft Corporation.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-// This header is used to compile the import library (via locale0_implib.cpp => locale0.cpp => xfacet => yvals.h).
+// This header is used to compile the import library
+// (via locale0_implib.cpp => locale0.cpp => xfacet => yvals.h and regex.cpp => awint.hpp => yvals.h).
 // MAJOR LIMITATIONS apply to what can be included here!
 // Before editing this file, read: /docs/import_library.md
 

stl/msbuild/stl_base/stl.files.settings.targets

@@ -158,6 +158,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
             $(CrtRoot)\github\stl\src\locale0_implib.cpp;
             $(CrtRoot)\github\stl\src\nothrow.cpp;
             $(CrtRoot)\github\stl\src\print.cpp;
+            $(CrtRoot)\github\stl\src\regex.cpp;
             $(CrtRoot)\github\stl\src\sharedmutex.cpp;
             $(CrtRoot)\github\stl\src\stacktrace.cpp;
             $(CrtRoot)\github\stl\src\syserror_import_lib.cpp;

stl/src/awint.hpp

@@ -2,6 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 // Internal definitions for A&W Win32 wrapper routines.
+
+// This file is compiled into the import library (via regex.cpp => awint.hpp).
+// MAJOR LIMITATIONS apply to what can be included here!
+// Before editing this file, read: /docs/import_library.md
+
 #pragma once
 
 #include <yvals.h>

stl/src/regex.cpp

@@ -0,0 +1,128 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// This file is compiled into the import library.
+// MAJOR LIMITATIONS apply to what can be included here!
+// Before editing this file, read: /docs/import_library.md
+
+#include <__msvc_xlocinfo_types.hpp>
+#include <clocale>
+#include <crtdefs.h>
+#include <cstdlib>
+#include <cstring>
+#include <internal_shared.h>
+
+#include <Windows.h>
+
+#undef _ENFORCE_ONLY_CORE_HEADERS
+#include "awint.hpp"
+
+extern "C" {
+
+// derived from xstrxfrm.cpp
+size_t __stdcall __std_regex_transform_primary_char(
+    _Out_writes_(end1 - string1) _Post_readable_size_(return) char* string1, char* end1,
+    _In_reads_(end2 - string2) const char* string2, const char* end2, _In_opt_ const _Collvec* ploc) noexcept {
+    size_t n1     = end1 - string1;
+    size_t n2     = end2 - string2;
+    size_t retval = static_cast<size_t>(-1);
+    UINT codepage;
+    const wchar_t* locale_name;
+
+    if (ploc == nullptr) {
+        locale_name = ___lc_locale_name_func()[LC_COLLATE];
+        codepage    = ___lc_collate_cp_func();
+    } else {
+        locale_name = ploc->_LocaleName;
+        codepage    = ploc->_Page;
+    }
+
+    if (locale_name == nullptr && codepage == CP_ACP) {
+        if (n2 <= n1) {
+            memcpy(string1, string2, n2);
+        }
+        retval = n2;
+    } else {
+        // Inquire size of dst string in BYTES
+        const int dstlen = __crtLCMapStringA(locale_name,
+            LCMAP_SORTKEY | LINGUISTIC_IGNORECASE | LINGUISTIC_IGNOREDIACRITIC | NORM_IGNOREKANATYPE | NORM_IGNOREWIDTH,
+            string2, static_cast<int>(n2), nullptr, 0, codepage, TRUE);
+
+        if (dstlen != 0) {
+            retval = dstlen;
+
+            // if not enough room, return amount needed
+            if (dstlen <= static_cast<int>(n1)) {
+                // Map src string to dst string
+                __crtLCMapStringA(locale_name,
+                    LCMAP_SORTKEY | LINGUISTIC_IGNORECASE | LINGUISTIC_IGNOREDIACRITIC | NORM_IGNOREKANATYPE
+                        | NORM_IGNOREWIDTH,
+                    string2, static_cast<int>(n2), string1, static_cast<int>(n1), codepage, TRUE);
+            }
+        }
+    }
+
+    return retval;
+}
+
+// derived from xwcsxfrm.cpp
+size_t __stdcall __std_regex_transform_primary_wchar_t(
+    _Out_writes_(end1 - string1) _Post_readable_size_(return) wchar_t* string1, wchar_t* end1,
+    _In_reads_(end2 - string2) const wchar_t* string2, const wchar_t* end2, _In_opt_ const _Collvec* ploc) noexcept {
+    size_t n1   = end1 - string1;
+    size_t n2   = end2 - string2;
+    size_t size = static_cast<size_t>(-1);
+    const wchar_t* locale_name;
+
+    if (ploc == nullptr) {
+        locale_name = ___lc_locale_name_func()[LC_COLLATE];
+    } else {
+        locale_name = ploc->_LocaleName;
+    }
+
+    if (locale_name == nullptr) {
+        if (n2 <= n1) {
+            memcpy(string1, string2, n2 * sizeof(wchar_t));
+        }
+        size = n2;
+    } else {
+        // When using LCMAP_SORTKEY, LCMapStringW handles BYTES not wide
+        // chars. We use a byte buffer to hold bytes and then convert the
+        // byte string to a wide char string and return this so it can be
+        // compared using wcscmp(). User's buffer is n1 wide chars, so
+        // use an internal buffer of n1 bytes.
+
+        auto bbuffer = _malloc_crt_t(unsigned char, n1);
+
+        if (bbuffer) {
+#pragma warning(push)
+#pragma warning(disable : 6386) // PREfast doesn't understand LCMAP_SORTKEY
+            size = __crtLCMapStringW(locale_name,
+                LCMAP_SORTKEY | LINGUISTIC_IGNORECASE | LINGUISTIC_IGNOREDIACRITIC | NORM_IGNOREKANATYPE
+                    | NORM_IGNOREWIDTH,
+                string2, static_cast<int>(n2), reinterpret_cast<wchar_t*>(bbuffer.get()), static_cast<int>(n1));
+#pragma warning(pop)
+
+            if (size == 0) {
+                // buffer not big enough, get size required.
+                size = __crtLCMapStringW(locale_name,
+                    LCMAP_SORTKEY | LINGUISTIC_IGNORECASE | LINGUISTIC_IGNOREDIACRITIC | NORM_IGNOREKANATYPE
+                        | NORM_IGNOREWIDTH,
+                    string2, static_cast<int>(n2), nullptr, 0);
+
+                if (size == 0) {
+                    size = static_cast<size_t>(-1); // default error
+                }
+            } else {
+                // string successfully mapped, convert to wide char
+
+                for (size_t i = 0; i < size; ++i) {
+                    string1[i] = static_cast<wchar_t>(bbuffer.get()[i]);
+                }
+            }
+        }
+    }
+
+    return size;
+}
+} // extern "C"

tests/libcxx/expected_results.txt

@@ -830,7 +830,6 @@ std/re/re.alg/re.alg.search/basic.pass.cpp FAIL
 std/re/re.alg/re.alg.search/ecma.pass.cpp FAIL
 std/re/re.alg/re.alg.search/extended.pass.cpp FAIL
 std/re/re.traits/lookup_collatename.pass.cpp FAIL
-std/re/re.traits/transform_primary.pass.cpp FAIL
 
 # Not analyzed, likely STL bugs. Various assertions.
 std/numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp FAIL