const char *
wdns_rcode_to_str(uint16_t rcode)
{
    switch (rcode) {
	case WDNS_R_NOERROR: return ("NOERROR");
	case WDNS_R_FORMERR: return ("FORMERR");
	case WDNS_R_SERVFAIL: return ("SERVFAIL");
	case WDNS_R_NXDOMAIN: return ("NXDOMAIN");
	case WDNS_R_NOTIMP: return ("NOTIMP");
	case WDNS_R_REFUSED: return ("REFUSED");
	case WDNS_R_YXDOMAIN: return ("YXDOMAIN");
	case WDNS_R_YXRRSET: return ("YXRRSET");
	case WDNS_R_NXRRSET: return ("NXRRSET");
	case WDNS_R_NOTAUTH: return ("NOTAUTH");
	case WDNS_R_NOTZONE: return ("NOTZONE");
	case WDNS_R_BADVERS: return ("BADVERS");
    }

    return (NULL);
}

static struct u16str {
    uint16_t u16;
    const char *str;
} rcodes[] = {
	{ WDNS_R_BADVERS, "BADVERS" },
	{ WDNS_R_FORMERR, "FORMERR" },
	{ WDNS_R_NOERROR, "NOERROR" },
	{ WDNS_R_NOTAUTH, "NOTAUTH" },
	{ WDNS_R_NOTIMP, "NOTIMP" },
	{ WDNS_R_NOTZONE, "NOTZONE" },
	{ WDNS_R_NXDOMAIN, "NXDOMAIN" },
	{ WDNS_R_NXRRSET, "NXRRSET" },
	{ WDNS_R_REFUSED, "REFUSED" },
	{ WDNS_R_SERVFAIL, "SERVFAIL" },
	{ WDNS_R_YXDOMAIN, "YXDOMAIN" },
	{ WDNS_R_YXRRSET, "YXRRSET" },
};

#define num_rcodes (sizeof(rcodes) / sizeof(struct u16str))

static int
cmp_u16str(const void *a, const void *b) {
    struct u16str *u1 = (struct u16str *) a;
    struct u16str *u2 = (struct u16str *) b;
    return (strcasecmp(u1->str, u2->str));
}

wdns_res
wdns_str_to_rcode(const char *str, uint16_t *out) {
    struct u16str key, *res;
    key.str = str;
    res = bsearch(&key, rcodes, num_rcodes, sizeof(struct u16str), cmp_u16str);
    if (res != NULL) {
        *out = res->u16;
        return (wdns_res_success);
    }
    return (wdns_res_failure);
}