*
 * This implementation is optimized for readability over efficiency.
 *
 * This implements non-transitional processing by preserving deviation characters.
 *
 * This implementation's STD3 rules are configured to `UseSTD3ASCIIRules=false`. This is
 * permissive and permits the `_` character.
 *
 * [mapping table]: https://www.unicode.org/reports/tr46/#IDNA_Mapping_Table
 * [mapping step]: https://www.unicode.org/reports/tr46/#ProcessingStepMap

  @Test fun mixedCasePunycode() {
    testDecodeOnly(
      unicode = "ليهمابتكلموشعربي؟",
      punycode = "Xn--EgBpDaJ6Bu4bXfGeHfVwXn",
    )
  }

  /**
   * It's invalid to have a label longer than 63 characters. If that's requested, the encoder may
   * overflow and return null.
   */
  @Test fun overflowEncodingOversizedLabel() {
    val a1000 = "a".repeat(1000)
    val a1000MaxCodePoint = a1000 + "\udbff\udfff"

      // character in that label
      return false
    }

    // Optimization: check whether hostname is too short to match the pattern. hostName must be at
    // least as long as the pattern because asterisk must match the whole left-most label and
    // hostname starts with a non-empty label. Thus, asterisk has to match one or more characters.
    if (hostname.length < pattern.length) {

    if (size == i + 1L) return null // Dangling escape.
    result.write(this, i)
    // Consume '\'.
    readByte()
    result.write(this, 1L) // The escaped character.
  }
}

/**
 * Consumes and returns a non-empty token, terminating at special characters in
 * [TOKEN_DELIMITERS]. Returns null if the buffer is empty or prefixed with a delimiter.
 */
private fun Buffer.readToken(): String? {

}

/**
 * Returns the next index in this at or after [startIndex] that is a character from
 * [characters]. Returns the input length if none of the requested characters can be found.
 */
private fun String.indexOfElement(
  characters: String,
  startIndex: Int = 0,
): Int {
  for (i in startIndex until length) {
    if (this[i] in characters) {
      return i
    }
  }
  return length

      } else if (firstIsRandalcat) {
        // 'If a string contains any RandALCat character, the string MUST NOT contain any LCat
        // character.'
        if (codePoint in lcatSet) return null

        // 'If a string contains any RandALCat character, a RandALCat character MUST be the last
        // character of the string.'
        if (validateBuffer.exhausted() && codePoint !in randalcatSet) return null
      } else {

   FFF9; INTERLINEAR ANNOTATION ANCHOR
   FFFA; INTERLINEAR ANNOTATION SEPARATOR
   FFFB; INTERLINEAR ANNOTATION TERMINATOR
   FFFC; OBJECT REPLACEMENT CHARACTER

            partCount++
            break@afterBoundaryLoop
          }

          1 -> {
            // "--": No more parts.
            if (whitespace) throw ProtocolException("unexpected characters after boundary")
            if (partCount == 0) throw ProtocolException("expected at least 1 part")
            noMoreParts = true
            return null
          }

          2, 3 -> {

    assertThat(formEncode(255)).isEqualTo("%C3%BF")
  }

  @Throws(IOException::class)
  private fun formEncode(codePoint: Int): String {
    // Wrap the codepoint with regular printable characters to prevent trimming.
    val body =
      FormBody.Builder()
        .add("a", String(intArrayOf('b'.code, codePoint, 'c'.code), 0, 3))
        .build()
    val buffer = Buffer()
    body.writeTo(buffer)

 *
 *  * In queries, ' ' is encoded to '+' and '+' is encoded to "%2B".
 *
 *  * Characters in `encodeSet` are percent-encoded.
 *
 *  * Control characters and non-ASCII characters are percent-encoded.
 *
 *  * All other characters are copied without transformation.
 *
 * @param alreadyEncoded true to leave '%' as-is; false to convert it to '%25'.