[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/ismbsle.cpp

@@ -0,0 +1,76 @@
+/***
+*ismbslead.c - True _ismbslead function
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Contains the function _ismbslead, which is a true context-sensitive
+*       MBCS lead-byte function.  While much less efficient than _ismbblead,
+*       it is also much more sophisticated, in that it determines whether a
+*       given sub-string pointer points to a lead byte or not, taking into
+*       account the context in the string.
+*
+*******************************************************************************/
+#ifndef _MBCS
+    #error This file should only be compiled with _MBCS defined
+#endif
+
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+
+
+/***
+* int _ismbslead(const unsigned char *string, const unsigned char *current);
+*
+*Purpose:
+*
+*       _ismbslead - Check, in context, for MBCS lead byte
+*
+*Entry:
+*       unsigned char *string   - ptr to start of string or previous known lead byte
+*       unsigned char *current  - ptr to position in string to be tested
+*
+*Exit:
+*       TRUE    : -1
+*       FALSE   : 0
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+extern "C" int __cdecl _ismbslead_l(
+        const unsigned char *string,
+        const unsigned char *current,
+        _locale_t plocinfo
+        )
+{
+        /* validation section */
+        _VALIDATE_RETURN(string != nullptr, EINVAL, 0);
+        _VALIDATE_RETURN(current != nullptr, EINVAL, 0);
+
+        _LocaleUpdate _loc_update(plocinfo);
+
+        if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
+            return 0;
+
+        while (string <= current && *string) {
+            if ( _ismbblead_l((*string), _loc_update.GetLocaleT()) ) {
+                if (string++ == current)        /* check lead byte */
+                    return -1;
+                if (!(*string))
+                    return 0;
+            }
+            ++string;
+        }
+
+        return 0;
+}
+
+extern "C" int (__cdecl _ismbslead)(
+        const unsigned char *string,
+        const unsigned char *current
+        )
+{
+        return _ismbslead_l(string, current, nullptr);
+}