[UCRT] Import Microsoft.Windows.SDK.CRTSource version 10.0.22621.3

Imported from https://www.nuget.org/packages/Microsoft.Windows.SDK.CRTSource/10.0.22621.3
License: MIT

sdk/lib/ucrt/mbstring/mbsrchr.cpp

@@ -0,0 +1,83 @@
+/***
+*mbsrchr.c - Search for last occurence of character (MBCS)
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Search for last occurence of character (MBCS)
+*
+*
+*******************************************************************************/
+#ifndef _MBCS
+    #error This file should only be compiled with _MBCS defined
+#endif
+
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+#include <stddef.h>
+#include <string.h>
+
+#pragma warning(disable:__WARNING_POTENTIAL_BUFFER_OVERFLOW_NULLTERMINATED) // 26018
+
+/***
+* _mbsrchr - Search for last occurence of character (MBCS)
+*
+*Purpose:
+*       Find the last occurrence of the specified character in
+*       the supplied string.  Handles MBCS chars/strings correctly.
+*
+*Entry:
+*       unsigned char *str = string to search in
+*       unsigned int c = character to search for
+*
+*Exit:
+*       returns pointer to last occurrence of c in str
+*       returns nullptr if c not found
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+extern "C" _CONST_RETURN unsigned char * __cdecl _mbsrchr_l(
+        const unsigned char *str,
+        unsigned int c,
+        _locale_t plocinfo
+        )
+{
+        char *r = nullptr;
+        unsigned int cc;
+        _LocaleUpdate _loc_update(plocinfo);
+
+        /* validation section */
+        _VALIDATE_RETURN(str != nullptr, EINVAL, 0);
+
+        if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
+            return (_CONST_RETURN unsigned char *)strrchr((const char *)str, c);
+
+        do {
+            cc = *str;
+            if ( _ismbblead_l(cc, _loc_update.GetLocaleT()) ) {
+                if(*++str) {
+                    if (c == ((cc<<8)|*str))
+                        r = (char *)str - 1;
+                }
+                else if(!r)
+                    /* return pointer to '\0' */
+                    r = (char *)str;
+            }
+            else if (c == cc)
+                r = (char *)str;
+        }
+        while (*str++);
+
+        return((_CONST_RETURN unsigned char *)r);
+}
+
+extern "C" _CONST_RETURN unsigned char * (__cdecl _mbsrchr)(
+        const unsigned char *str,
+        unsigned int c
+        )
+{
+    return _mbsrchr_l(str, c, nullptr);
+}