* such as "::c000:201".
   *
   * @param ip {@link InetAddress} to be converted to an address string
   * @return {@code String} containing the text-formatted IP address
   * @since 10.0
   */
  public static String toAddrString(InetAddress ip) {
    checkNotNull(ip);
    if (ip instanceof Inet4Address) {
      // For IPv4, Java's formatting is good enough.

import java.net.InetAddress;
import java.text.ParseException;
import org.jspecify.annotations.Nullable;

/**
 * A syntactically valid host specifier, suitable for use in a URI. This may be either a numeric IP
 * address in IPv4 or IPv6 notation, or a domain name.
 *
 * <p>Because this class is intended to represent host specifiers which can reasonably be used in a

   * such as "::c000:201".
   *
   * @param ip {@link InetAddress} to be converted to an address string
   * @return {@code String} containing the text-formatted IP address
   * @since 10.0
   */
  public static String toAddrString(InetAddress ip) {
    checkNotNull(ip);
    if (ip instanceof Inet4Address) {
      // For IPv4, Java's formatting is good enough.

import okhttp3.Dns.Companion.SYSTEM

/**
 * A domain name service that resolves IP addresses for host names. Most applications will use the
 * [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *
 * Implementations of this interface must be safe for concurrent use.
 */

  companion object {
    /** Obtain a host string containing either an actual host name or a numeric IP address. */
    val InetSocketAddress.socketHost: String get() {
      // The InetSocketAddress was specified with a string (either a numeric IP or a host name). If
      // it is a name, all IPs for that name should be tried. If it is an IP address, only that IP
      // address should be tried.
      val address = address ?: return hostName

 *    [proxy selector][java.net.ProxySelector] is used. It may return multiple proxies to attempt.
 *  * **IP address:** whether connecting directly to an origin server or a proxy, opening a socket
 *    requires an IP address. The DNS server may return multiple IP addresses to attempt.
 *
 * Each route is a specific selection of these options.
 */
class Route(
  @get:JvmName("address") val address: Address,

/**
 * This test binds two different web servers (IPv4 and IPv6) to the same port, but on different
 * local IP addresses. Requests made to `127.0.0.1` will reach the IPv4 server, and requests made to
 * `::1` will reach the IPv6 server.
 *
 * By orchestrating two different servers with the same port but different IP addresses, we can
 * test what OkHttp does when both are reachable, or if only one is reachable.
 *

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

/**
 * Utility methods and classes for networking (such as IP addresses and domain names).
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 *
 * @author Craig Berry
 */
@CheckReturnValue
@NullMarked

import java.net.InetAddress
import okhttp3.internal.interleave

/**
 * Implementation of HappyEyeballs Sorting Addresses.
 *
 * The current implementation does not address any of:
 *  - Async DNS split by IP class
 *  - Stateful handling of connectivity results
 *  - The prioritisation of addresses
 *
 * https://datatracker.ietf.org/doc/html/rfc8305#section-4
 */

 * decimal digits and dots. This pattern matches strings like "a:.23" and "54" that are neither IP
 * addresses nor hostnames; they will be verified as IP addresses (which is a more strict
 * verification).
 */
private val VERIFY_AS_IP_ADDRESS = "([0-9a-fA-F]*:[0-9a-fA-F:.]*)|([\\d.]+)".toRegex()

/** Returns true if this string is not a host name and might be an IP address. */
fun String.canParseAsIpAddress(): Boolean = VERIFY_AS_IP_ADDRESS.matches(this)