From f30a9375bab6b99901f4478e0264ceb8e86eccba Mon Sep 17 00:00:00 2001
From: Alex Guteniev <gutenev@gmail.com>
Date: Tue, 25 Jul 2023 14:42:47 +0300
Subject: [PATCH 1/3] Towards #3858 : resize_and_overwrite

---
 stl/inc/bitset  | 12 ++++++------
 stl/inc/xstring | 17 ++++++++++++++---
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/stl/inc/bitset b/stl/inc/bitset
index b91f8a6eb38..2c438e7dc21 100644
--- a/stl/inc/bitset
+++ b/stl/inc/bitset
@@ -347,13 +347,13 @@ public:
     _NODISCARD _CONSTEXPR23 basic_string<_Elem, _Tr, _Alloc> to_string(
         const _Elem _Elem0 = static_cast<_Elem>('0'), const _Elem _Elem1 = static_cast<_Elem>('1')) const {
         // convert bitset to string
-        basic_string<_Elem, _Tr, _Alloc> _Str(_Bits, _Elem0);
-        for (size_t _Pos = 0; _Pos < _Bits; ++_Pos) {
-            if (_Subscript(_Bits - 1 - _Pos)) {
-                _Str[_Pos] = _Elem1;
+        basic_string<_Elem, _Tr, _Alloc> _Str;
+        _Str._Resize_and_overwrite(_Bits, [this, _Elem0, _Elem1](_Elem* _Buf, size_t _Len) {
+            for (size_t _Pos = 0; _Pos < _Len; ++_Pos) {
+                _Buf[_Pos] = _Subscript(_Len - 1 - _Pos) ? _Elem1 : _Elem0;
             }
-        }
-
+            return _Len;
+        });
         return _Str;
     }
 
diff --git a/stl/inc/xstring b/stl/inc/xstring
index 455e6ae8f12..1ab31f10c1e 100644
--- a/stl/inc/xstring
+++ b/stl/inc/xstring
@@ -4158,11 +4158,16 @@ public:
         }
     }
 
-#if _HAS_CXX23
 #pragma warning(push)
 #pragma warning(disable : 4018) // '<=': signed/unsigned mismatch (we compare to 0 before _New_size below, so it's safe)
     template <class _Operation>
-    constexpr void resize_and_overwrite(_CRT_GUARDOVERFLOW const size_type _New_size, _Operation _Op) {
+    constexpr void 
+#if _HAS_CXX23
+        resize_and_overwrite
+#else // ^^^ _HAS_CXX23 / !_HAS_CXX23 vvv
+        _Resize_and_overwrite
+#endif // ^^^ !_HAS_CXX23 ^^^
+        (_CRT_GUARDOVERFLOW const size_type _New_size, _Operation _Op) {
         if (_Mypair._Myval2._Myres < _New_size) {
             _Reallocate_grow_by(_New_size - _Mypair._Myval2._Mysize,
                 [](_Elem* const _New_ptr, const _Elem* const _Old_ptr, const size_type _Old_size) {
@@ -4180,7 +4185,13 @@ public:
         _Eos(static_cast<size_type>(_Result_size));
     }
 #pragma warning(pop)
-#endif // _HAS_CXX23
+
+#if _HAS_CXX23
+    template <class _Operation>
+    constexpr void _Resize_and_overwrite(_CRT_GUARDOVERFLOW const size_type _New_size, _Operation _Op) {
+        return resize_and_overwrite(_New_size, _Op);
+    }
+#endif // !_HAS_CXX23
 
     _NODISCARD _CONSTEXPR20 size_type capacity() const noexcept {
         return _Mypair._Myval2._Myres;

From 2696c9dfdf07c49cad2883c69bff24ebdd197370 Mon Sep 17 00:00:00 2001
From: Alex Guteniev <gutenev@gmail.com>
Date: Tue, 25 Jul 2023 15:15:30 +0300
Subject: [PATCH 2/3] formating

---
 stl/inc/xstring | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/stl/inc/xstring b/stl/inc/xstring
index 1ab31f10c1e..53fe7e645b9 100644
--- a/stl/inc/xstring
+++ b/stl/inc/xstring
@@ -4161,7 +4161,7 @@ public:
 #pragma warning(push)
 #pragma warning(disable : 4018) // '<=': signed/unsigned mismatch (we compare to 0 before _New_size below, so it's safe)
     template <class _Operation>
-    constexpr void 
+    constexpr void
 #if _HAS_CXX23
         resize_and_overwrite
 #else // ^^^ _HAS_CXX23 / !_HAS_CXX23 vvv
@@ -4191,7 +4191,7 @@ public:
     constexpr void _Resize_and_overwrite(_CRT_GUARDOVERFLOW const size_type _New_size, _Operation _Op) {
         return resize_and_overwrite(_New_size, _Op);
     }
-#endif // !_HAS_CXX23
+#endif // _HAS_CXX23
 
     _NODISCARD _CONSTEXPR20 size_type capacity() const noexcept {
         return _Mypair._Myval2._Myres;

From fbe38a04dd9720c4aed422b9d6a3dd5e0dd0e27e Mon Sep 17 00:00:00 2001
From: Alex Guteniev <gutenev@gmail.com>
Date: Wed, 26 Jul 2023 17:38:34 +0300
Subject: [PATCH 3/3] no void return

---
 stl/inc/xstring | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stl/inc/xstring b/stl/inc/xstring
index 53fe7e645b9..adb18c1f429 100644
--- a/stl/inc/xstring
+++ b/stl/inc/xstring
@@ -4189,7 +4189,7 @@ public:
 #if _HAS_CXX23
     template <class _Operation>
     constexpr void _Resize_and_overwrite(_CRT_GUARDOVERFLOW const size_type _New_size, _Operation _Op) {
-        return resize_and_overwrite(_New_size, _Op);
+        resize_and_overwrite(_New_size, _Op);
     }
 #endif // _HAS_CXX23