third_party/ulib/musl/src/stdio/vswscanf.c

#include "libc.h"
#include "stdio_impl.h"
#include <wchar.h>

static size_t wstring_read(FILE* f, unsigned char* buf, size_t len) {
    const wchar_t* src = f->cookie;
    size_t k;

    if (!src)
        return 0;

    k = wcsrtombs((void*)f->buf, &src, f->buf_size, 0);
    if (k == (size_t)-1) {
        f->rpos = f->rend = 0;
        return 0;
    }

    f->rpos = f->buf;
    f->rend = f->buf + k;
    f->cookie = (void*)src;

    if (!len || !k)
        return 0;

    *buf = *f->rpos++;
    return 1;
}

int vswscanf(const wchar_t* restrict s, const wchar_t* restrict fmt, va_list ap) {
    unsigned char buf[256];
    FILE f = {
        .buf = buf, .buf_size = sizeof buf, .cookie = (void*)s, .read = wstring_read, .lock = -1};
    return vfwscanf(&f, fmt, ap);
}