static int nid_cb(const char *elem, int len, void *arg)
{
    nid_cb_st *narg = arg;
    size_t i;
    int nid;
    char etmp[20];
    if (elem == NULL)
        return 0;
    if (narg->nidcnt == MAX_CURVELIST)
        return 0;
    if (len > (int)(sizeof(etmp) - 1))
        return 0;
    memcpy(etmp, elem, len);
    etmp[len] = 0;
    nid = EC_curve_nist2nid(etmp);
    if (nid == NID_undef)
        nid = OBJ_sn2nid(etmp);
    if (nid == NID_undef)
        nid = OBJ_ln2nid(etmp);
    if (nid == NID_undef)
        return 0;
    for (i = 0; i < narg->nidcnt; i++)
        if (narg->nid_arr[i] == nid)
            return 0;
    narg->nid_arr[narg->nidcnt++] = nid;
    return 1;
}

Unknown