BytesRef matchOutput = null;

        int index = 0;
        while (start + index < src.length) {
            final int codePoint = Character.codePointAt(src, start + index, src.length);
            if (fst.findTargetArc(ignoreCase ? Character.toLowerCase(codePoint) : codePoint, scratchArc, scratchArc, fstReader) == null) {
                return matchOutput;
            }

  try {
    val peek = peek()
    for (i in 0 until codePointLimit) {
      if (peek.exhausted()) {
        break
      }
      val codePoint = peek.readUtf8CodePoint()
      if (Character.isISOControl(codePoint) && !Character.isWhitespace(codePoint)) {
        return false
      }
    }
    return true
  } catch (_: EOFException) {
    return false // Truncated UTF-8 sequence.
  }

) {
  /**
   * Returns true if the [codePoint] was applied successfully. Returns false if it was disallowed.
   */
  fun map(
    codePoint: Int,
    sink: BufferedSink,
  ): Boolean {
    val index =
      mappings.binarySearch {
        when {
          it.sourceCodePoint1 < codePoint -> -1
          it.sourceCodePoint0 > codePoint -> 1
          else -> 0
        }
      }

  val sections: String,
  val ranges: String,
  val mappings: String,
) {
  /**
   * Returns true if the [codePoint] was applied successfully. Returns false if it was disallowed.
   */
  fun map(
    codePoint: Int,
    sink: BufferedSink,
  ): Boolean {
    val sectionsIndex = findSectionsIndex(codePoint)

    val rangesPosition = sections.read14BitInt(sectionsIndex + 2)

    val rangesLimit =
      when {

    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)

  val bufferA = Buffer().writeUtf8(host)
  val bufferB = Buffer()

  // 1. Map, from bufferA to bufferB.
  while (!bufferA.exhausted()) {
    val codePoint = bufferA.readUtf8CodePoint()
    if (!IDNA_MAPPING_TABLE.map(codePoint, bufferB)) return null
  }

  // 2. Normalize, from bufferB to bufferA.
  val normalized = normalizeNfc(bufferB.readUtf8())
  bufferA.writeUtf8(normalized)