Array(256) {
      format("%8s", Integer.toBinaryString(it)).replace(' ', '0')
    }

  init {
    FLAGS[FLAG_NONE] = ""
    FLAGS[FLAG_END_STREAM] = "END_STREAM"

    val prefixFlags = intArrayOf(FLAG_END_STREAM)

    FLAGS[FLAG_PADDED] = "PADDED"
    for (prefixFlag in prefixFlags) {
      FLAGS[prefixFlag or FLAG_PADDED] = FLAGS[prefixFlag] + "|PADDED"
    }

 * [twitter_hpack]: https://github.com/twitter/hpack
 */
object Huffman {
  // Appendix C: Huffman Codes
  // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-12#appendix-B
  private val CODES =
    intArrayOf(
      0x1ff8,
      0x7fffd8,
      0xfffffe2,
      0xfffffe3,
      0xfffffe4,
      0xfffffe5,
      0xfffffe6,
      0xfffffe7,
      0xfffffe8,
      0xffffea,
      0x3ffffffc,

  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)
    buffer.skip(3) // Skip "a=b" prefix.
    return buffer.readUtf8(buffer.size - 1) // Skip the "c" suffix.