// relayAddressesOrder checks the latency to each relay, rounds latency down to
// the closest 50ms, and puts them in buckets of 50ms latency ranges. Then
// shuffles each bucket, and returns all addresses starting with the ones from
// the lowest latency bucket, ending with the highest latency buceket.
func relayAddressesOrder(input []string) []string {
buckets := make(map[int][]string)
for _, relay := range input {
latency, err := osutil.GetLatencyForURL(relay)
if err != nil {
latency = time.Hour
}
id := int(latency/time.Millisecond) / 50
buckets[id] = append(buckets[id], relay)
}
var ids []int
for id, bucket := range buckets {
shuffle(bucket)
ids = append(ids, id)
}
sort.Ints(ids)
addresses := make([]string, len(input))
for _, id := range ids {
addresses = append(addresses, buckets[id]...)
}
return addresses
}
// relayAddressesSortedByLatency adds local latency to the relay, and sorts them
// by sum latency, and returns the addresses.
func relayAddressesSortedByLatency(input []string) []string {
relays := make(relayList, len(input))
for i, relay := range input {
if latency, err := osutil.GetLatencyForURL(relay); err == nil {
relays[i] = relayWithLatency{relay, int(latency / time.Millisecond)}
} else {
relays[i] = relayWithLatency{relay, int(time.Hour / time.Millisecond)}
}
}
sort.Sort(relays)
addresses := make([]string, len(relays))
for i, relay := range relays {
addresses[i] = relay.relay
}
return addresses
}