third_party/ulib/musl/src/multibyte/wcsnrtombs.c

#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;

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

    while (ws && n && ((n2 = wn) >= n || n2 > 32)) {
        if (n2 >= n)
            n2 = n;
        wn -= n2;
        l = wcsrtombs(s, &ws, n2, 0);
        if (!(l + 1)) {
            cnt = l;
            n = 0;
            break;
        }
        if (s != buf) {
            s += l;
            n -= l;
        }
        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;
}