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

  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",

  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.

      0xfa,
      0x16,
      0x17,
      0x18,
      0x0,
      0x1,
      0x2,
      0x19,
      0x1a,
      0x1b,
      0x1c,
      0x1d,
      0x1e,
      0x1f,
      0x5c,
      0xfb,
      0x7ffc,
      0x20,
      0xffb,
      0x3fc,
      0x1ffa,
      0x21,
      0x5d,
      0x5e,
      0x5f,
      0x60,
      0x61,
      0x62,
      0x63,
      0x64,