override val rangeStart: Int,
    private val mappedTo: ByteString,
  ) : MappedRange {
    val b1: Int
      get() {
        val b3bit8 = mappedTo[0] and 0x80 != 0
        return if (b3bit8) 123 else 122
      }

    val b2: Int
      get() = mappedTo[0] and 0x7f
  }

  data class Inline2(
    override val rangeStart: Int,
    private val mappedTo: ByteString,
  ) : MappedRange {
    val b1: Int

        is MappedRange.External -> {
          // Write the mapping.
          val mappingOffset: Int
          val mappedTo = range.mappedTo.utf8()
          val mappingIndex = mappingsBuffer.indexOf(mappedTo)
          if (mappingIndex == -1) {
            mappingOffset = mappingsBuffer.length
            mappingsBuffer.append(mappedTo)
          } else {
            mappingOffset = mappingIndex
          }

          // Write the range bytes.

        sourceCodePoint0.toInt(),
        sourceCodePoint1.toInt(),
        type,
        mappedTo.readByteString(),
      )
  }

  return SimpleIdnaMappingTable(result)
}

internal data class Mapping(
  val sourceCodePoint0: Int,
  val sourceCodePoint1: Int,
  val type: Int,
  val mappedTo: ByteString,
) {
  val section: Int
    get() = sourceCodePoint0 and 0x1fff80

    sourceCodePoint1: Int,
    mappedToCodePoints: List<Int>,
  ): Mapping =
    Mapping(
      sourceCodePoint0 = sourceCodePoint0,
      sourceCodePoint1 = sourceCodePoint1,
      type = TYPE_MAPPED,
      mappedTo =
        Buffer()
          .also {
            for (cp in mappedToCodePoints) {
              it.writeUtf8CodePoint(cp)
            }
          }.readByteString(),
    )

 *    119 : Ignored.
 *    120 : Valid.
 *    121 : Disallowed
 *    122 : Mapped inline to the sequence: [b2].
 *    123 : Mapped inline to the sequence: [b2a].
 *    124 : Mapped inline to the sequence: [b2, b3].
 *    125 : Mapped inline to the sequence: [b2a, b3].
 *    126 : Mapped inline to the sequence: [b2, b3a].
 *    127 : Mapped inline to the sequence: [b2a, b3a].
 *
 * The range goes until the beginning of the next range.

0046          ; mapped                 ; 0066          # 1.1  LATIN CAPITAL LETTER F
0047          ; mapped                 ; 0067          # 1.1  LATIN CAPITAL LETTER G
0048          ; mapped                 ; 0068          # 1.1  LATIN CAPITAL LETTER H
0049          ; mapped                 ; 0069          # 1.1  LATIN CAPITAL LETTER I
004A          ; mapped                 ; 006A          # 1.1  LATIN CAPITAL LETTER J

      i += 2
    }
  }
  return result.readUtf8()
}

/**
 * Returns the canonical address for [address]. If [address] is an IPv6 address that is mapped to an
 * IPv4 address, this returns the IPv4-mapped address. Otherwise, this returns [address].
 *
 * https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses
 */
internal fun canonicalizeInetAddress(address: ByteArray): ByteArray =

		if err != nil {
			return nil, err
		}

		if m.mapped == nil {
			m.mapped = make([]byte, m.size)
			m.filled = make([]byte, m.size)
		}

		set := m.parityData[m.data]
		if set == nil {
			set = make(map[int][]byte)
		}
		set[idx] = b
		m.parityData[m.data] = set

		// Combine
		start := len(b) * idx
		if start >= len(m.mapped) {
			continue
		}

 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01}
 *   <dt>An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.
 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 ff ff c0 a8 00 01}
 * </dl>
 *
 * <p>A few notes about IPv6 "IPv4 mapped" addresses and their observed use in Java.
 *
 * <p>"IPv4 mapped" addresses were originally a representation of IPv4 addresses for use on an IPv6

 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01}
 *   <dt>An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.
 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 ff ff c0 a8 00 01}
 * </dl>
 *
 * <p>A few notes about IPv6 "IPv4 mapped" addresses and their observed use in Java.
 *
 * <p>"IPv4 mapped" addresses were originally a representation of IPv4 addresses for use on an IPv6