// appendCodePoint(). The Punycode algorithm processes code points in increasing code-point
    // order, not in increasing index order.
    val codePoints = mutableListOf<Int>()

    // consume all code points before the last delimiter (if there is one)
    //  and copy them to output, fail on any non-basic code point
    val lastDelimiter = string.lastIndexOf('-', limit)
    if (lastDelimiter >= pos) {

 *
 * The first element on each line is a single hex code point (like 0041) or a hex code point range
 * (like 0030..0039).
 *
 * The second element on each line is a mapping type, like `valid` or `mapped`.
 *
 * For lines that contain a mapping target, the next thing is a sequence of hex code points (like
 * 0031 2044 0034).
 *
 * All other data is ignored.
 */

   FDD0-FDEF; [NONCHARACTER CODE POINTS]
   FFFE-FFFF; [NONCHARACTER CODE POINTS]
   1FFFE-1FFFF; [NONCHARACTER CODE POINTS]
   2FFFE-2FFFF; [NONCHARACTER CODE POINTS]
   3FFFE-3FFFF; [NONCHARACTER CODE POINTS]
   4FFFE-4FFFF; [NONCHARACTER CODE POINTS]
   5FFFE-5FFFF; [NONCHARACTER CODE POINTS]
   6FFFE-6FFFF; [NONCHARACTER CODE POINTS]
   7FFFE-7FFFF; [NONCHARACTER CODE POINTS]
   8FFFE-8FFFF; [NONCHARACTER CODE POINTS]

 */
class Stringprep(
  /** Unassigned code points. */
  val unassigned: CodePointSet,
  /** Mappings. Note table B.3 is not used in RFC 3491. */
  val mapping: CodePointMapping,
  /** Prohibited code points. */
  val prohibitSet: CodePointSet,
  /** RandALCat code points; bidi category is "R" or "AL". */
  val randalcatSet: CodePointSet,
  /** LCat code points; bidi category is "L". */
  val lcatSet: CodePointSet,
) {

 *
 * Code Points in Sections
 * =======================
 *
 * The full range of code points is 0..0x10fffe. We can represent any of these code points with 21
 * bits.
 *
 * We split each code point into a 14-bit prefix and a 7-bit suffix. All code points with the same
 * prefix are called a 'section'. There are 128 code points per section.
 *
 * Ranges Data (32,612 bytes)

    "output": null
  },
  {
    "comment": "U+FFFD character encoded in Punycode",
    "input": "xn--zn7c.com",
    "output": null
  },
  {
    "comment": "Label longer than 63 code points",
    "input": "x01234567890123456789012345678901234567890123456789012345678901x",
    "output": "x01234567890123456789012345678901234567890123456789012345678901x"
  },
  {

  @Suppress("ktlint:standard:max-line-length")
  val knownFailures =
    setOf(
      // OkHttp rejects empty labels.
      "x..xn--zca",
      "x..ß",
      // OkHttp rejects labels longer than 63 code points, the web platform tests don't.
      "x01234567890123456789012345678901234567890123456789012345678901x.xn--zca",
      "x01234567890123456789012345678901234567890123456789012345678901x.ß",

  private val uriStrippedCodePoints = StringBuilder()

  /**
   * Configure code points to be escaped for conversion to `java.net.URI`. That class is more
   * strict than the others.
   */
  fun escapeForUri(vararg codePoints: Int) =
    apply {
      uriEscapedCodePoints.append(String(*codePoints))
    }

  /**
   * Configure code points to be stripped in conversion to `java.net.URI`. That class is more

   *
   * ```
   *    180C; ; Map to nothing
   *    0041; 0061; Case map
   *    0390; 03B9 0308 0301; Case map
   * ```
   *
   * Each line maps from a single hexadecimal code point to zero or more hexadecimal code points.
   * Elements are delimited by semicolons with a comment at the end of the line.
   */
  fun readCodePointMapping(path: Path): MappingListCodePointMapping {

   *
   * https://www.unicode.org/reports/tr46/#Validity_Criteria
   */
  @Test
  fun hostnameInPunycodeNfcAndNfd() {
    // café can be NFC (é is one code point) or NFD (e plus ´ as two code points).
    val hostNfc = "café.com"
    val hostNfcPunycode = "xn--caf-dma.com"
    val hostNfd = "café.com"
    val hostNfdPunycode = "xn--cafe-yvc.com"