source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/multibyte/wcsnrtombs.c@ 352

#include <wchar.h>

size_t wcsnrtombs(char *restrict dst, const wchar_t **restrict wcs, size_t wn, size_t n, mbstate_t *restrict st)
{
        size_t l, cnt=0, n2;
        char *s, buf[256];
        const wchar_t *ws = *wcs;
        const wchar_t *tmp_ws;

        if (!dst) s = buf, n = sizeof buf;
        else s = dst;

        while ( ws && n && ( (n2=wn)>=n || n2>32 ) ) {
                if (n2>=n) n2=n;
                tmp_ws = ws;
                l = wcsrtombs(s, &ws, n2, 0);
                if (!(l+1)) {
                        cnt = l;
                        n = 0;
                        break;
                }
                if (s != buf) {
                        s += l;
                        n -= l;
                }
                wn = ws ? wn - (ws - tmp_ws) : 0;
                cnt += l;
        }
        if (ws) while (n && wn) {
                l = wcrtomb(s, *ws, 0);
                if ((l+1)<=1) {
                        if (!l) ws = 0;
                        else cnt = l;
                        break;
                }
                ws++; wn--;
                /* safe - this loop runs fewer than sizeof(buf) times */
                s+=l; n-=l;
                cnt += l;
        }
        if (dst) *wcs = ws;
        return cnt;
}