[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/mbslen_s.cpp

@@ -0,0 +1,84 @@
+/***
+*mbslen_s.c - Find length of MBCS string
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Find length of MBCS string
+*
+*******************************************************************************/
+#ifndef _MBCS
+    #error This file should only be compiled with _MBCS defined
+#endif
+
+#include <corecrt_internal.h>
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+#include <string.h>
+
+/***
+* _mbsnlen - Find length of MBCS string
+*
+*Purpose:
+*       Find the length of the MBCS string (in characters).
+*
+*Entry:
+*       unsigned char *s = string
+*       size_t maxsize
+*
+*Exit:
+*       Returns the number of MBCS chars in the string.
+*       Only the first sizeInBytes bytes of the string are inspected: if the null
+*       terminator is not found, sizeInBytes is returned.
+*       If the string is null terminated in sizeInBytes bytes, the return value
+*       will always be less than sizeInBytes.
+*       Returns (size_t)-1 if something went wrong.
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+size_t __cdecl _mbsnlen_l(
+        const unsigned char *s,
+        size_t sizeInBytes,
+        _locale_t plocinfo
+        )
+{
+        size_t n, size;
+        _LocaleUpdate _loc_update(plocinfo);
+
+        if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
+            return strnlen((const char *)s, sizeInBytes);
+
+        /* Note that we do not check if s == nullptr, because we do not
+         * return errno_t...
+         */
+
+        /* Note that sizeInBytes here is the number of bytes, not mb characters! */
+        for (n = 0, size = 0; size < sizeInBytes && *s; n++, s++, size++)
+        {
+            if ( _ismbblead_l(*s, _loc_update.GetLocaleT()) )
+                        {
+                                size++;
+                                if (size >= sizeInBytes)
+                                {
+                                        break;
+                                }
+                if (*++s == '\0')
+                                {
+                    break;
+                                }
+            }
+        }
+
+                return (size >= sizeInBytes ? sizeInBytes : n);
+}
+
+size_t __cdecl _mbsnlen(
+        const unsigned char *s,
+        size_t maxsize
+        )
+{
+    return _mbsnlen_l(s,maxsize, nullptr);
+}