github.com/afumu/libc@v0.0.6/musl/src/multibyte/wcsnrtombs.c (about)

     1  #include <wchar.h>
     2  
     3  size_t wcsnrtombs(char *restrict dst, const wchar_t **restrict wcs, size_t wn, size_t n, mbstate_t *restrict st)
     4  {
     5  	size_t l, cnt=0, n2;
     6  	char *s, buf[256];
     7  	const wchar_t *ws = *wcs;
     8  	const wchar_t *tmp_ws;
     9  
    10  	if (!dst) s = buf, n = sizeof buf;
    11  	else s = dst;
    12  
    13  	while ( ws && n && ( (n2=wn)>=n || n2>32 ) ) {
    14  		if (n2>=n) n2=n;
    15  		tmp_ws = ws;
    16  		l = wcsrtombs(s, &ws, n2, 0);
    17  		if (!(l+1)) {
    18  			cnt = l;
    19  			n = 0;
    20  			break;
    21  		}
    22  		if (s != buf) {
    23  			s += l;
    24  			n -= l;
    25  		}
    26  		wn = ws ? wn - (ws - tmp_ws) : 0;
    27  		cnt += l;
    28  	}
    29  	if (ws) while (n && wn) {
    30  		l = wcrtomb(s, *ws, 0);
    31  		if ((l+1)<=1) {
    32  			if (!l) ws = 0;
    33  			else cnt = l;
    34  			break;
    35  		}
    36  		ws++; wn--;
    37  		/* safe - this loop runs fewer than sizeof(buf) times */
    38  		s+=l; n-=l;
    39  		cnt += l;
    40  	}
    41  	if (dst) *wcs = ws;
    42  	return cnt;
    43  }