* fills, it is doubled.
 */
@Suppress("NAME_SHADOWING")
object Hpack {
  private const val PREFIX_4_BITS = 0x0f
  private const val PREFIX_5_BITS = 0x1f
  private const val PREFIX_6_BITS = 0x3f
  private const val PREFIX_7_BITS = 0x7f

  private const val SETTINGS_HEADER_TABLE_SIZE = 4_096

  /**
   * The decoder has ultimate control of the maximum size of the dynamic table but we can choose

            //     || byte1 == (byte) 0xF4 && byte2 > (byte) 0x8F)
            || (((byte1 << 28) + (byte2 - (byte) 0x90)) >> 30) != 0
            // Third byte trailing-byte test
            || bytes[index++] > (byte) 0xBF
            // Fourth byte trailing-byte test
            || bytes[index++] > (byte) 0xBF) {
          return false;
        }
      }
    }
  }

    sectionIndexBuffer.writeByte((section and 0x3f80) shr 7)

    // Section index.
    sectionIndexBuffer.writeByte((sectionOffset and 0x3f80) shr 7)
    sectionIndexBuffer.writeByte(sectionOffset and 0x7f)

    // Ranges.
    for (range in sectionMappedRanges) {
      rangesBuffer.writeByte(range.rangeStart)

      when (range) {
        is MappedRange.Constant -> {
          rangesBuffer.writeByte(range.b1)

      }

      while (!encodedCharBuffer.exhausted()) {
        val b = encodedCharBuffer.readByte().toInt() and 0xff
        writeByte('%'.code)
        writeByte(HEX_DIGITS[b shr 4 and 0xf].code)
        writeByte(HEX_DIGITS[b and 0xf].code)
      }
    } else {
      // This character doesn't need encoding. Just copy it over.
      writeUtf8CodePoint(codePoint)
    }

  }

  public void testEncodedLength_validStrings2() {
    HashMap<Integer, Integer> utf8Lengths = new HashMap<>();
    utf8Lengths.put(0x00, 1);
    utf8Lengths.put(0x7f, 1);
    utf8Lengths.put(0x80, 2);
    utf8Lengths.put(0x7ff, 2);
    utf8Lengths.put(0x800, 3);
    utf8Lengths.put(MIN_SUPPLEMENTARY_CODE_POINT - 1, 3);
    utf8Lengths.put(MIN_SUPPLEMENTARY_CODE_POINT, 4);
    utf8Lengths.put(MAX_CODE_POINT, 4);

      return plusSign;
    } else if (cp <= 0x7F) {
      // Single byte UTF-8 characters
      // Start with "%--" and fill in the blanks
      char[] dest = new char[3];
      dest[0] = '%';
      dest[2] = upperHexDigits[cp & 0xF];
      dest[1] = upperHexDigits[cp >>> 4];
      return dest;
    } else if (cp <= 0x7ff) {
      // Two byte UTF-8 characters [cp >= 0x80 && cp <= 0x7ff]

  // is masked in order to correspond to the current table size. For example, if the table size
  // is 128 then the mask is 127 == 0x7f, keeping the bottom 7 bits of the hash value.
  // If a key hashes to 0x89abcdef the mask reduces it to 0x89abcdef & 0x7f == 0x6f. We'll call this
  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be

    testDecodes(base64(), "Zg====", "f");
  }

  public void testBase64InvalidDecodings() {
    // These contain bytes not in the decodabet.
    assertFailsToDecode(base64(), "A\u007f", "Unrecognized character: 0x7f");
    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");

  @Test
  fun dynamicallyGrowsBeyond64Entries() {
    // Lots of headers need more room!
    hpackReader = Hpack.Reader(bytesIn, 16384, 4096)
    bytesIn.writeByte(0x3F) // Dynamic table size update (size = 16384).
    bytesIn.writeByte(0xE1)
    bytesIn.writeByte(0x7F)
    for (i in 0..255) {
      bytesIn.writeByte(0x40) // Literal indexed
      bytesIn.writeByte(0x0a) // Literal name (len = 10)
      bytesIn.writeUtf8("custom-foo")

  // is masked in order to correspond to the current table size. For example, if the table size
  // is 128 then the mask is 127 == 0x7f, keeping the bottom 7 bits of the hash value.
  // If a key hashes to 0x89abcdef the mask reduces it to 0x89abcdef & 0x7f == 0x6f. We'll call this
  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be