[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/mbschr.cpp

@@ -0,0 +1,84 @@
+/***
+* mbschr.c - Search MBCS string for character
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Search MBCS string for a character
+*
+*******************************************************************************/
+#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
+
+/***
+* _mbschr - Search MBCS string for character
+*
+*Purpose:
+*       Search the given string for the specified character.
+*       MBCS characters are handled correctly.
+*
+*Entry:
+*       unsigned char *string = string to search
+*       int c = character to search for
+*
+*Exit:
+*       returns a pointer to the first occurence of the specified char
+*       within the string.
+*
+*       returns nullptr if the character is not found n the string.
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+
+extern "C" _CONST_RETURN unsigned char * __cdecl _mbschr_l(
+        const unsigned char *string,
+        unsigned int c,
+        _locale_t plocinfo
+        )
+{
+        unsigned short cc = '\0';
+        _LocaleUpdate _loc_update(plocinfo);
+
+        /* validation section */
+        _VALIDATE_RETURN(string != nullptr, EINVAL, nullptr);
+
+        if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
+            return (_CONST_RETURN unsigned char *)strchr((const char *)string, (int)c);
+
+        for (; (cc = *string) != '\0'; string++)
+        {
+            if ( _ismbblead_l(cc, _loc_update.GetLocaleT()) )
+            {
+                if (*++string == '\0')
+                    return nullptr;        /* error */
+                if ( c == (unsigned int)((cc << 8) | *string) ) /* DBCS match */
+                    return (unsigned char *)(string - 1);
+            }
+            else if (c == (unsigned int)cc)
+                break;  /* SBCS match */
+        }
+
+        if (c == (unsigned int)cc)      /* check for SBCS match--handles NUL char */
+            return (unsigned char *)(string);
+
+        return nullptr;
+}
+
+extern "C" _CONST_RETURN unsigned char * (__cdecl _mbschr)(
+        const unsigned char *string,
+        unsigned int c
+        )
+{
+    return _mbschr_l(string, c, nullptr);
+}