var commaFound = false
  loop@ while (!exhausted()) {
    when (this[0]) {
      ','.code.toByte() -> {
        // Consume ','.
        readByte()
        commaFound = true
      }

      ' '.code.toByte(), '\t'.code.toByte() -> {
        readByte()
        // Consume space or tab.
      }

      else -> {
        break@loop
      }
    }
  }
  return commaFound
}

  fun writeObjectIdentifier(s: String) {
    val utf8 = Buffer().writeUtf8(s)
    val v1 = utf8.readDecimalLong()
    require(utf8.readByte() == '.'.code.toByte())
    val v2 = utf8.readDecimalLong()
    writeVariableLengthLong(v1 * 40 + v2)

    while (!utf8.exhausted()) {
      require(utf8.readByte() == '.'.code.toByte())
      val vN = utf8.readDecimalLong()
      writeVariableLengthLong(vN)
    }
  }

		t.Errorf("r.Len(): got %d, want %d", got, want)
	}
}

var UnreadRuneErrorTests = []struct {
	name string
	f    func(*Reader)
}{
	{"Read", func(r *Reader) { r.Read([]byte{0}) }},
	{"ReadByte", func(r *Reader) { r.ReadByte() }},
	{"UnreadRune", func(r *Reader) { r.UnreadRune() }},
	{"Seek", func(r *Reader) { r.Seek(0, io.SeekCurrent) }},
	{"WriteTo", func(r *Reader) { r.WriteTo(&Buffer{}) }},
}

      when (select(optionsDot)) {
        DELIMITER_DOT -> {
          if (readByte() != '.'.code.toByte()) throw IOException("expected '..'")
          readHexadecimalUnsignedLong()
        }

        else -> {
          sourceCodePoint0
        }
      }

    skipWhitespace()
    if (readByte() != ';'.code.toByte()) throw IOException("expected ';'")

    // "valid" or "mapped"

	n = copy(b, r.s[off:])
	if n < len(b) {
		err = io.EOF
	}
	return
}

// ReadByte implements the [io.ByteReader] interface.
func (r *Reader) ReadByte() (byte, error) {
	r.prevRune = -1
	if r.i >= int64(len(r.s)) {
		return 0, io.EOF
	}
	b := r.s[r.i]
	r.i++
	return b, nil
}

// UnreadByte complements [Reader.ReadByte] in implementing the [io.ByteScanner] interface.
func (r *Reader) UnreadByte() error {

  writeByte(medium.ushr(8) and 0xff)
  writeByte(medium and 0xff)
}

@Throws(IOException::class)
internal fun BufferedSource.readMedium(): Int =
  (
    readByte() and 0xff shl 16
      or (readByte() and 0xff shl 8)
      or (readByte() and 0xff)
  )

/** Run [block] until it either throws an [IOException] or completes. */
internal inline fun ignoreIoExceptions(block: () -> Unit) {
  try {
    block()

		buf.WriteByte(testString[1])
		c, err := buf.ReadByte()
		if want := testString[1]; err != nil || c != want {
			t.Errorf("ReadByte: got (%q, %v), want (%q, %v)", c, err, want, nil)
		}
		c, err = buf.ReadByte()
		if err != io.EOF {
			t.Errorf("ReadByte: got (%q, %v), want (%q, %v)", c, err, byte(0), io.EOF)
		}
	}
}

          dynamicTable[index] = entry
        }
        dynamicTableByteCount += delta
      }

      @Throws(IOException::class)
      private fun readByte(): Int = source.readByte() and 0xff

      @Throws(IOException::class)
      fun readInt(
        firstByte: Int,
        prefixMask: Int,
      ): Int {
        val prefix = firstByte and prefixMask

    }

    /**
     * Reads a single byte value.
     * @return the byte value
     * @throws IOException if an I/O error occurs
     */
    public byte readByte() throws IOException {
        return this.dis.readByte();
    }

    /**
     * Reads a 16-bit short value with proper alignment and byte order.
     * @return the short value in little-endian format

  @Override
  int skipBytes(int n);

  @CanIgnoreReturnValue // to skip a byte
  @Override
  boolean readBoolean();

  @CanIgnoreReturnValue // to skip a byte
  @Override
  byte readByte();

  @CanIgnoreReturnValue // to skip a byte
  @Override
  int readUnsignedByte();

  @CanIgnoreReturnValue // to skip some bytes
  @Override
  short readShort();