if (byte2 > (byte) 0xBF
            // Overlong? 5 most significant bits must not all be zero.
            || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
            // Check for illegal surrogate codepoints.
            || (byte1 == (byte) 0xED && byte2 >= (byte) 0xA0)
            // Third byte trailing-byte test.
            || bytes[index++] > (byte) 0xBF) {
          return false;
        }
      } else {

        final byte b3 = DECODE_TABLE[inData.charAt(inIndex + 3)];
        outData[outIndex] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3);
        outData[outIndex + 1] = (byte) (b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
        outData[outIndex + 2] = (byte) (b2 << 6 & 0xc0 | b3 & 0x3f);
    }

    private static void decode1byte(final String inData, final int inIndex, final byte[] outData, final int outIndex) {

      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
      get() {
        val b2bit8 = mappedTo[0] and 0x80 != 0
        val b3bit8 = mappedTo[1] and 0x80 != 0

  const val FLAG_END_HEADERS = 0x4 // Used for headers and continuation.
  const val FLAG_END_PUSH_PROMISE = 0x4
  const val FLAG_PADDED = 0x8 // Used for headers and data.
  const val FLAG_PRIORITY = 0x20 // Used for headers.
  const val FLAG_COMPRESSED = 0x20 // Used for data.

  /** Lookup table for valid frame types. */
  private val FRAME_NAMES =
    arrayOf(
      "DATA",
      "HEADERS",
      "PRIORITY",
      "RST_STREAM",

    assertThat(Buffer().writeUtf8("white\t space").isProbablyUtf8()).isTrue()
    assertThat(Buffer().writeByte(0x80).isProbablyUtf8()).isTrue()
    assertThat(Buffer().writeByte(0x00).isProbablyUtf8()).isFalse()
    assertThat(Buffer().writeByte(0xc0).isProbablyUtf8()).isFalse()
  }

  public void testCollisionsDueToIncorrectSignExtension() {
    byte[] col1 = new byte[] {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0x80};
    byte[] col2 = new byte[] {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0x81};
    byte[] col3 = new byte[] {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, (byte) 0xff};

    ImmutableSet<HashCode> hashCodes =
        ImmutableSet.of(

          return 0x80;
        } else if (userFriendly.matches("(?i)(?:French|Latin|Western.*European)")) {
          // Mostly 1-byte UTF-8 sequences, mixed with occasional 2-byte
          // sequences - "Western European" text
          return 0x90;
        } else if (userFriendly.matches("(?i)(?:Branch.*Prediction.*Hostile)")) {
          // Defeat branch predictor for: c < 0x80 ; branch taken 50% of the time.

      // Encode '+' as '%2B' since we permit ' ' to be encoded as either '+' or '%20'.
      writeUtf8(if (alreadyEncoded) "+" else "%2B")
    } else if (codePoint < 0x20 ||
      codePoint == 0x7f ||
      codePoint >= 0x80 &&
      !unicodeAllowed ||
      codePoint.toChar() in encodeSet ||
      codePoint == '%'.code &&
      (!alreadyEncoded || strict && !input.isPercentEncoded(i, limit))
    ) {

        new byte[] {
          0x01, (byte) 0xc0, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x14, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x04, 0x00,
          0x00, 0x00, 0x00, 0x14,
          0x00, 0x00, 0x00, 0x18,
          0x28, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x02, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00

    hasher = HASH_FN.newHasher();
    hasher
        .putByte((byte) 0x01)
        .putByte((byte) 0x01)
        .putByte((byte) 0x00)
        .putByte((byte) 0x01)
        .putByte((byte) 0x00)
        .putByte((byte) 0x00)
        .putByte((byte) 0x00)
        .putByte((byte) 0x00);
    assertEquals(hashCode, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();
    hasher
        .putChar((char) 0x0101)