public void testIsWellFormed_4BytesSamples() {
    // Valid 4 byte.
    assertWellFormed(0xF0, 0xA4, 0xAD, 0xA2);
    // Bad trailing bytes
    assertNotWellFormed(0xF0, 0xA4, 0xAD, 0x7F);
    assertNotWellFormed(0xF0, 0xA4, 0xAD, 0xC0);
    // Special cases for byte2
    assertNotWellFormed(0xF0, 0x8F, 0xAD, 0xA2);
    assertNotWellFormed(0xF4, 0x90, 0xAD, 0xA2);
  }

  /** Tests some hard-coded test cases. */

        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) {

     * @param i
     *            the number to convert
     */
    public static void appendHex(final StringBuilder buf, final byte i) {
        buf.append(Character.forDigit((i & 0xf0) >> 4, 16));
        buf.append(Character.forDigit(i & 0x0f, 16));
    }

    /**
     * Appends the hexadecimal string representation of a number to the given StringBuilder.
     *
     * @param buf

          when {
            b == 0x80 -> {
              // 10000000
              throw IOException("index == 0")
            }
            b and 0x80 == 0x80 -> {
              // 1NNNNNNN
              val index = readInt(b, PREFIX_7_BITS)
              readIndexedHeader(index - 1)
            }
            b == 0x40 -> {
              // 01000000

    assertThat(newReader(byteStream()).readInt(0xe0 or 10, 31)).isEqualTo(10)
  }

  @Test
  fun readMultibyteInt() {
    assertThat(newReader(byteStream(154, 10)).readInt(31, 31)).isEqualTo(1337)
  }

  @Test
  fun writeSingleByteInt() {
    hpackWriter!!.writeInt(10, 31, 0)
    assertBytes(10)
    hpackWriter!!.writeInt(10, 31, 0xe0)
    assertBytes(0xe0 or 10)
  }

  @Test

      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(