Fix entropy range encoding in octree pointcloud compression

Size of frequency table elements was wrongly computed when frequency was a power of 2.
This led to faulty frequency table encoding with 1 missing byte.
During decoding, the frequency was decoded to 0 as 1 byte is missing, leading to
division by 0 and thus error.

The frequencyTableByteSize is now correctly computed.

io/include/pcl/compression/impl/entropy_range_coder.hpp

@@ -294,7 +294,7 @@ pcl::StaticRangeCoder::encodeIntVectorToStream (std::vector<unsigned int>& input
 
   // calculate amount of bytes per frequency table entry
   std::uint8_t frequencyTableByteSize = static_cast<std::uint8_t> (std::ceil (
-      std::log2 (static_cast<double> (cFreqTable_[static_cast<std::size_t> (frequencyTableSize - 1)])) / 8.0));
+      std::log2 (static_cast<double> (cFreqTable_[static_cast<std::size_t> (frequencyTableSize - 1)] + 1)) / 8.0));
 
   // write size of frequency table to output stream
   outputByteStream_arg.write (reinterpret_cast<const char*> (&frequencyTableSize), sizeof(frequencyTableSize));