[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/mbsnset.cpp

@@ -0,0 +1,143 @@
+/***
+*mbsnset.c - Sets first n charcaters of string to given character (MBCS)
+*
+*       Copyright (c) Microsoft Corporation.  All rights reserved.
+*
+*Purpose:
+*       Sets first n charcaters of string to given character (MBCS)
+*
+*******************************************************************************/
+#ifndef _MBCS
+    #error This file should only be compiled with _MBCS defined
+#endif
+
+#include <corecrt_internal_mbstring.h>
+#include <locale.h>
+#include <string.h>
+
+
+/***
+* _mbsnset - Sets first n charcaters of string to given character (MBCS)
+*
+*Purpose:
+*       Sets the first n characters of string to the supplied
+*       character value.  If the length of string is less than n,
+*       the length of string is used in place of n.  Handles
+*       MBCS chars correctly.
+*
+*       There are several factors that make this routine complicated:
+*               (1) The fill value may be 1 or 2 bytes long.
+*               (2) The fill operation may end by hitting the count value
+*               or by hitting the end of the string.
+*               (3) A null terminating char is NOT placed at the end of
+*               the string.
+*
+*       Cases to be careful of (both of these can occur at once):
+*               (1) Leaving an "orphaned" trail byte in the string (e.g.,
+*               overwriting a lead byte but not the corresponding trail byte).
+*               (2) Writing only the 1st byte of a 2-byte fill value because the
+*               end of string was encountered.
+*
+*Entry:
+*       unsigned char *string = string to modify
+*       unsigned int val = value to fill string with
+*       size_t count = count of characters to fill
+*
+*
+*Exit:
+*       Returns string = now filled with char val
+*
+*Uses:
+*
+*Exceptions:
+*       Input parameters are validated. Refer to the validation section of the function.
+*
+*******************************************************************************/
+
+extern "C" unsigned char * __cdecl _mbsnset_l(
+        unsigned char *string,
+        unsigned int val,
+        size_t count,
+        _locale_t plocinfo
+        )
+{
+        unsigned char  *start = string;
+        unsigned int leadbyte = 0;
+        unsigned char highval, lowval;
+        _LocaleUpdate _loc_update(plocinfo);
+
+        /* validation section */
+        _VALIDATE_RETURN(string != nullptr || count == 0, EINVAL, nullptr);
+
+        /*
+         * leadbyte flag indicates if the last byte we overwrote was
+         * a lead byte or not.
+         */
+_BEGIN_SECURE_CRT_DEPRECATION_DISABLE
+        if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
+            return (unsigned char *)_strnset((char *)string, val, count);
+_END_SECURE_CRT_DEPRECATION_DISABLE
+
+        highval = static_cast<unsigned char>(val >> 8);
+        if (highval != 0)
+        {
+
+            /* double byte value */
+
+            lowval = (unsigned char)(val & 0x00ff);
+
+            if(lowval=='\0')
+            {
+                _ASSERTE(("invalid MBCS pair passed to mbsnset",0));
+
+                /* Ideally we would return nullptr here and signal an error
+                    condition. But since this function has no other
+                    error modes, there would be a good chance of crashing
+                    the caller. So instead we fill the string with spaces
+                    to ensure that no information leaks through
+                    unexpectedly. Anyway, we do set errno to EINVAL.
+                */
+                errno = EINVAL;
+                lowval=highval=' ';
+            }
+
+            while (count-- && *string) {
+                leadbyte = _ismbbtruelead_l(leadbyte, *string, _loc_update.GetLocaleT());
+                *string++ = highval;
+
+                if (*string) {
+                    leadbyte = _ismbbtruelead_l(leadbyte, *string, _loc_update.GetLocaleT());
+                    *string++ = lowval;
+                }
+                else
+                    /* overwrite orphaned highval byte */
+                    *(string-1) = ' ';
+            }
+        }
+
+        else {
+            /* single byte value */
+
+            while (count-- && *string) {
+                leadbyte = _ismbbtruelead_l(leadbyte, *string, _loc_update.GetLocaleT());
+                *string++ = (unsigned char)val;
+            }
+        }
+
+        /* overwrite orphaned trailing byte, if necessary */
+        if(leadbyte && *string)
+            *string = ' ';
+
+        return( start );
+}
+
+unsigned char * (__cdecl _mbsnset)(
+        unsigned char *string,
+        unsigned int val,
+        size_t count
+        )
+{
+_BEGIN_SECURE_CRT_DEPRECATION_DISABLE
+    return _mbsnset_l(string, val, count, nullptr);
+_END_SECURE_CRT_DEPRECATION_DISABLE
+}