From acb8d34cc77603dc9ee90c70e26d131fd8db045e Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34@live.cn>
Date: Wed, 19 Jul 2023 07:46:37 +0800
Subject: [PATCH] Restore refactoring for `valarray`

---
 stl/inc/valarray | 43 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 11 deletions(-)

diff --git a/stl/inc/valarray b/stl/inc/valarray
index 26fff41e33..2598ebaab0 100644
--- a/stl/inc/valarray
+++ b/stl/inc/valarray
@@ -74,54 +74,71 @@ public:
 
     using value_type = _Ty;
 
-    valarray() = default; // construct empty valarray
+    valarray() noexcept /* strengthened */ { // construct empty valarray
+        _Tidy_init();
+    }
 
     explicit valarray(size_t _Count) { // construct with _Count * _Ty()
+        _Tidy_init();
         _Grow(_Count);
     }
 
     valarray(const _Ty& _Val, size_t _Count) { // construct with _Count * _Val
+        _Tidy_init();
         _Grow(_Count, &_Val);
     }
 
     valarray(const _Ty* _Ptr, size_t _Count) { // construct with [_Ptr, _Ptr + _Count)
+        _Tidy_init();
         _Grow(_Count, _Ptr, 1);
     }
 
     valarray(const valarray& _Right) {
+        _Tidy_init();
         _Grow(_Right.size(), _Right._Myptr, 1);
     }
 
     valarray(const slice_array<_Ty>& _Slicearr) {
+        _Tidy_init();
         *this = _Slicearr;
     }
 
     valarray(const gslice_array<_Ty>& _Gslicearr) {
+        _Tidy_init();
         *this = _Gslicearr;
     }
 
     valarray(const mask_array<_Ty>& _Maskarr) {
+        _Tidy_init();
         *this = _Maskarr;
     }
 
     valarray(const indirect_array<_Ty>& _Indarr) {
+        _Tidy_init();
         *this = _Indarr;
     }
 
-    valarray(valarray&& _Right) noexcept
-        : _Myptr(_STD exchange(_Right._Myptr, static_cast<_Ty*>(nullptr))),
-          _Mysize(_STD exchange(_Right._Mysize, size_t{0})) {}
+    valarray(valarray&& _Right) noexcept {
+        _Tidy_init();
+        _Assign_rv(_STD move(_Right));
+    }
 
     valarray& operator=(valarray&& _Right) noexcept {
+        _Assign_rv(_STD move(_Right));
+        return *this;
+    }
+
+    void _Assign_rv(valarray&& _Right) noexcept {
         if (this != _STD addressof(_Right)) { // clear this and steal from _Right
             _Tidy_deallocate();
-            _Myptr  = _STD exchange(_Right._Myptr, static_cast<_Ty*>(nullptr));
-            _Mysize = _STD exchange(_Right._Mysize, size_t{0});
+            _Myptr  = _Right._Myptr;
+            _Mysize = _Right._Mysize;
+            _Right._Tidy_init();
         }
-        return *this;
     }
 
     valarray(initializer_list<_Ty> _Ilist) {
+        _Tidy_init();
         _Grow(_Ilist.size(), _Ilist.begin(), 1);
     }
 
@@ -532,6 +549,11 @@ private:
         }
     }
 
+    void _Tidy_init() noexcept {
+        _Mysize = 0;
+        _Myptr  = nullptr;
+    }
+
     void _Tidy_deallocate() noexcept {
         if (_Myptr) { // destroy elements
             for (size_t _Idx = 0; _Idx < _Mysize; ++_Idx) {
@@ -549,8 +571,7 @@ private:
             }
         }
 
-        _Mysize = 0;
-        _Myptr  = nullptr;
+        _Tidy_init();
     }
 
     void _Assign(size_t _Newsize, const _Ty* _Ptr) {
@@ -565,8 +586,8 @@ private:
         }
     }
 
-    _Ty* _Myptr    = nullptr; // current storage reserved for array
-    size_t _Mysize = 0; // current length of sequence
+    _Ty* _Myptr; // current storage reserved for array
+    size_t _Mysize; // current length of sequence
 };
 
 #if _HAS_CXX17