1 /*
2 * This code was written by Rich Felker in 2010; no copyright is claimed.
3 * This code is in the public domain. Attribution is appreciated but
4 * unnecessary.
5 */
6
7 #include <wchar.h>
8
wcsnrtombs(char * restrict dst,const wchar_t ** restrict wcs,size_t wn,size_t n,mbstate_t * restrict st)9 size_t wcsnrtombs(char *restrict dst, const wchar_t **restrict wcs, size_t wn, size_t n, mbstate_t *restrict st)
10 {
11 size_t l, cnt=0, n2;
12 char *s, buf[256];
13 const wchar_t *ws = *wcs;
14
15 if (!dst) s = buf, n = sizeof buf;
16 else s = dst;
17
18 while ( ws && n && ( (n2=wn)>=n || n2>32 ) ) {
19 if (n2>=n) n2=n;
20 wn -= n2;
21 l = wcsrtombs(s, &ws, n2, 0);
22 if (!(l+1)) {
23 cnt = l;
24 n = 0;
25 break;
26 }
27 if (s != buf) {
28 s += l;
29 n -= l;
30 }
31 cnt += l;
32 }
33 if (ws) while (n && wn) {
34 l = wcrtomb(s, *ws, 0);
35 if ((l+1)<=1) {
36 if (!l) ws = 0;
37 else cnt = l;
38 break;
39 }
40 ws++; wn--;
41 /* safe - this loop runs fewer than sizeof(buf) times */
42 s+=l; n-=l;
43 cnt++;
44 }
45 if (dst) *wcs = ws;
46 return cnt;
47 }
48