mappings.binarySearch {
        when {
          it.sourceCodePoint1 < codePoint -> -1
          it.sourceCodePoint0 > codePoint -> 1
          else -> 0
        }
      }

    // Code points must be in 0..0x10ffff.
    require(index in mappings.indices) { "unexpected code point: $codePoint" }

    val mapping = mappings[index]
    var result = true

    when (mapping.type) {
      TYPE_IGNORED -> Unit

      val deltaN = i / (codePoints.size + 1)
      if (n > Int.MAX_VALUE - deltaN) return false // Prevent overflow.
      n += deltaN
      i %= (codePoints.size + 1)

      if (n > 0x10ffff) return false // Not a valid code point.

      codePoints.add(i, n)

      i++
    }

    for (codePoint in codePoints) {
      result.writeUtf8CodePoint(codePoint)
    }

    return true

  }

  @Test fun outOfBounds() {
    assertFailsWith<IllegalArgumentException> {
      table.map(-1, Buffer())
    }
    table.map(0, Buffer()) // Lowest legal code point.
    table.map(0x10ffff, Buffer()) // Highest legal code point.
    assertFailsWith<IllegalArgumentException> {
      table.map(0x110000, Buffer())
    }
  }

  @Test fun binarySearchEvenSizedRange() {

      0x7fffe4, 0x1fffdc, 0x3fffd8, 0x7fffe5, 0x3fffd9, 0x7fffe6, 0x7fffe7, 0xffffef,
      0x3fffda, 0x1fffdd, 0xfffe9, 0x3fffdb, 0x3fffdc, 0x7fffe8, 0x7fffe9, 0x1fffde, 0x7fffea,
      0x3fffdd, 0x3fffde, 0xfffff0, 0x1fffdf, 0x3fffdf, 0x7fffeb, 0x7fffec, 0x1fffe0,
      0x1fffe1, 0x3fffe0, 0x1fffe2, 0x7fffed, 0x3fffe1, 0x7fffee, 0x7fffef, 0xfffea, 0x3fffe2,
      0x3fffe3, 0x3fffe4, 0x7ffff0, 0x3fffe5, 0x3fffe6, 0x7ffff1, 0x3ffffe0, 0x3ffffe1,

        }

    val b2: Int
      get() = absoluteDelta shr 7 and 0x7f

    val b3: Int
      get() = absoluteDelta and 0x7f

    companion object {
      const val MAX_VALUE = 0x3FFFF
    }
  }

  data class External(
    override val rangeStart: Int,
    val mappedTo: ByteString,
  ) : MappedRange

   BFFFE-BFFFF; [NONCHARACTER CODE POINTS]
   CFFFE-CFFFF; [NONCHARACTER CODE POINTS]
   DFFFE-DFFFF; [NONCHARACTER CODE POINTS]
   EFFFE-EFFFF; [NONCHARACTER CODE POINTS]
   FFFFE-FFFFF; [NONCHARACTER CODE POINTS]

internal val UNICODE_BOMS =
  Options.of(
    // UTF-8.
    "efbbbf".decodeHex(),
    // UTF-16BE.
    "feff".decodeHex(),
    // UTF-16LE.
    "fffe".decodeHex(),
    // UTF-32BE.
    "0000ffff".decodeHex(),
    // UTF-32LE.
    "ffff0000".decodeHex(),
  )

/**
 * Returns an array containing only elements found in this array and also in [other]. The returned
 * elements are in the same order as in this.

      return
    }

    if (length % 6 != 0) throw IOException("TYPE_SETTINGS length % 6 != 0: $length")
    val settings = Settings()
    for (i in 0 until length step 6) {
      var id = source.readShort() and 0xffff
      val value = source.readInt()

      when (id) {
        // SETTINGS_HEADER_TABLE_SIZE
        1 -> {
        }

        // SETTINGS_ENABLE_PUSH
        2 -> {

            else -> InetAddress.getByName(domainName)
          }
        }

        else -> throw ProtocolException("unsupported address type: $addressType")
      }

    val port = fromSource.readShort() and 0xffff

    when (command) {
      COMMAND_CONNECT -> {
        val toSocket = Socket(toAddress, port)
        val localAddress = toSocket.localAddress.address
        if (localAddress.size != 4) {

    val flags = buf.readShort().toInt() and 0xffff
    require(flags shr 15 != 0) { "not a response" }

    val responseCode = flags and 0xf

    if (responseCode == NXDOMAIN) {
      throw UnknownHostException("$hostname: NXDOMAIN")
    } else if (responseCode == SERVFAIL) {
      throw UnknownHostException("$hostname: SERVFAIL")
    }

    val questionCount = buf.readShort().toInt() and 0xffff