*/
internal object DnsRecordCodec {
  private const val SERVFAIL = 2
  private const val NXDOMAIN = 3
  const val TYPE_A = 0x0001
  const val TYPE_AAAA = 0x001c
  private const val TYPE_PTR = 0x000c
  private val ASCII = Charsets.US_ASCII

  fun encodeQuery(
    host: String,
    type: Int,
  ): ByteString =
    Buffer().apply {
      writeShort(0) // query id

    @JvmField val TLS_RSA_WITH_NULL_MD5 = init("SSL_RSA_WITH_NULL_MD5", 0x0001)

    @JvmField val TLS_RSA_WITH_NULL_SHA = init("SSL_RSA_WITH_NULL_SHA", 0x0002)

    @JvmField val TLS_RSA_EXPORT_WITH_RC4_40_MD5 = init("SSL_RSA_EXPORT_WITH_RC4_40_MD5", 0x0003)

    @JvmField val TLS_RSA_WITH_RC4_128_MD5 = init("SSL_RSA_WITH_RC4_128_MD5", 0x0004)

	// but these seem to be the values agreed on by tools.
	s_IFMT   = 0xf000
	s_IFSOCK = 0xc000
	s_IFLNK  = 0xa000
	s_IFREG  = 0x8000
	s_IFBLK  = 0x6000
	s_IFDIR  = 0x4000
	s_IFCHR  = 0x2000
	s_IFIFO  = 0x1000
	s_ISUID  = 0x800
	s_ISGID  = 0x400
	s_ISVTX  = 0x200

	msdosDir      = 0x10
	msdosReadOnly = 0x01
)

// Mode returns the permission and mode bits for the [FileHeader].

    assertThat(
      mergeAdjacentRanges(
        listOf(
          Mapping(0x0041, 0x0041, TYPE_MAPPED, "a".encodeUtf8()),
          Mapping(0x0042, 0x0042, TYPE_MAPPED, "b".encodeUtf8()),
        ),
      ),
    ).containsExactly(
      Mapping(0x0041, 0x0041, TYPE_MAPPED, "a".encodeUtf8()),
      Mapping(0x0042, 0x0042, TYPE_MAPPED, "b".encodeUtf8()),
    )
  }

  @Test fun simplifyCanonicalizesType() {

                    O_RDONLY,
                    FILE_WRITE_ATTRIBUTES,
                    FILE_SHARE_READ | FILE_SHARE_WRITE,
                    dir,
                    dir != 0 ? 0x0001 : 0x0040) ) {
                    th.send(
                        new Trans2SetFileInformation(th.getConfig(), f.getFid(), attrs | dir, ctime, mtime, atime),

        .putChar((char) 0x0101)
        .putChar((char) 0x0100)
        .putChar((char) 0x0000)
        .putChar((char) 0x0000);
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putBytes(new byte[] {0x01, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00});
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putLong(0x0000000001000101L);

        .putChar((char) 0x0101)
        .putChar((char) 0x0100)
        .putChar((char) 0x0000)
        .putChar((char) 0x0000);
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putBytes(new byte[] {0x01, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00});
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putLong(0x0000000001000101L);

        .putChar((char) 0x0101)
        .putChar((char) 0x0100)
        .putChar((char) 0x0000)
        .putChar((char) 0x0000);
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putBytes(new byte[] {0x01, 0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00});
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher.putLong(0x0000000001000101L);

    HashCode unused = sink.hash();
    sink.assertInvariants(8);
    sink.assertBytes(expected);
  }

  public void testShort() {
    Sink sink = new Sink(4);
    sink.putShort((short) 0x0201);
    HashCode unused = sink.hash();
    sink.assertInvariants(2);
    sink.assertBytes(new byte[] {1, 2, 0, 0}); // padded with zeros
  }

  public void testInt() {
    Sink sink = new Sink(4);

        // version schemes not really supported: fully transformed as qualifier
        checkVersionParsing("1.0.1b", 0, 0, 0, 0, "1.0.1b");
        checkVersionParsing("1.0M2", 0, 0, 0, 0, "1.0M2");
        checkVersionParsing("1.0RC2", 0, 0, 0, 0, "1.0RC2");
        checkVersionParsing("1.1.2.beta1", 1, 1, 2, 0, "beta1");
        checkVersionParsing("1.7.3.beta1", 1, 7, 3, 0, "beta1");