cuserid: support invocation with a null pointer argument

[musl] / src / multibyte / mbsnrtowcs.c

diff --git a/src/multibyte/mbsnrtowcs.c b/src/multibyte/mbsnrtowcs.c
index f42e30d..931192e 100644 (file)
--- a/src/multibyte/mbsnrtowcs.c
+++ b/src/multibyte/mbsnrtowcs.c
@@ -1,22 +1,11 @@
-/* 
- * This code was written by Rich Felker in 2010; no copyright is claimed.
- * This code is in the public domain. Attribution is appreciated but
- * unnecessary.
- */
-
-#include <stdlib.h>
-#include <inttypes.h>
 #include <wchar.h>
-#include <errno.h>
-#include <stdio.h>
-
-#include "internal.h"
 
-size_t mbsnrtowcs(wchar_t *wcs, const char **src, size_t n, size_t wn, mbstate_t *st)
+size_t mbsnrtowcs(wchar_t *restrict wcs, const char **restrict src, size_t n, size_t wn, mbstate_t *restrict st)
 {
        size_t l, cnt=0, n2;
        wchar_t *ws, wbuf[256];
        const char *s = *src;
+       const char *tmp_s;
 
        if (!wcs) ws = wbuf, wn = sizeof wbuf / sizeof *wbuf;
        else ws = wcs;
@@ -27,7 +16,7 @@ size_t mbsnrtowcs(wchar_t *wcs, const char **src, size_t n, size_t wn, mbstate_t
 
        while ( s && wn && ( (n2=n/4)>=wn || n2>32 ) ) {
                if (n2>=wn) n2=wn;
-               n -= n2;
+               tmp_s = s;
                l = mbsrtowcs(ws, &s, n2, st);
                if (!(l+1)) {
                        cnt = l;
@@ -38,6 +27,7 @@ size_t mbsnrtowcs(wchar_t *wcs, const char **src, size_t n, size_t wn, mbstate_t
                        ws += l;
                        wn -= l;
                }
+               n = s ? n - (s - tmp_s) : 0;
                cnt += l;
        }
        if (s) while (wn && n) {