[Debug] fix pcd io small probability bug

[GCaptainNemo]

I encountered a bug in parsing the PCD header. The reason is that the first point and first field x (FLOAT32) of my PCD is 13.265933990478516, which corresponds exactly to "DATA" after decoding, causing the code to not decode PCD correctly.

#Here is an python example to explain
import struct

float_number = 13.265933990478516
binary_data = struct.pack('f', float_number)
hex_string = binary_data.hex()
ascii_string = bytes.fromhex(hex_string).decode('ascii')
print(ascii_string)  # output ： DATA

So I submitted this PR, in addition to DATA, the code also needs to use the following string ("binary", "binary_compressed") to determine if it is HEADER.

[mvieth]

@GCaptainNemo Thanks, this looks like an interesting case. Unfortunately, your current code change makes many tests fail. I have a slightly different suggestion that will hopefully work:
Change

pcl/io/src/pcd_io.cpp

Lines 326 to 335 in af7b2d5

	if (line_type.substr (0, 4) == "DATA")
	{
	data_idx = static_cast<int> (fs.tellg ());
	if (st.at (1).substr (0, 17) == "binary_compressed")
	data_type = 2;
	else
	if (st.at (1).substr (0, 6) == "binary")
	data_type = 1;
	continue;
	}

To:

      if (line_type.substr (0, 4) == "DATA")
      {
        if (st.at (1).substr (0, 17) == "binary_compressed")
          data_type = 2;
        else if (st.at (1).substr (0, 6) == "binary")
          data_type = 1;
        else if (st.at (1).substr (0, 5) == "ascii")
          data_type = 0;
        else {
          PCL_WARN("[pcl::PCDReader::readHeader] Unknown DATA format: %s\n", line.c_str());
          continue;
        }
        data_idx = static_cast<int> (fs.tellg ());
        break; // DATA is the last header entry, everything after it will be interpreted as point cloud data
      }

For reference: https://pcl.readthedocs.io/projects/tutorials/en/master/pcd_file_format.html

[GCaptainNemo]

@GCaptainNemo Thanks, this looks like an interesting case. Unfortunately, your current code change makes many tests fail. I have a slightly different suggestion that will hopefully work: Change

pcl/io/src/pcd_io.cpp

Lines 326 to 335 in af7b2d5

	if (line_type.substr (0, 4) == "DATA")
	{
	data_idx = static_cast<int> (fs.tellg ());
	if (st.at (1).substr (0, 17) == "binary_compressed")
	data_type = 2;
	else
	if (st.at (1).substr (0, 6) == "binary")
	data_type = 1;
	continue;
	}

To:

      if (line_type.substr (0, 4) == "DATA")
      {
        if (st.at (1).substr (0, 17) == "binary_compressed")
          data_type = 2;
        else if (st.at (1).substr (0, 6) == "binary")
          data_type = 1;
        else if (st.at (1).substr (0, 5) == "ascii")
          data_type = 0;
        else {
          PCL_WARN("[pcl::PCDReader::readHeader] Unknown DATA format: %s\n", line.c_str());
          continue;
        }
        data_idx = static_cast<int> (fs.tellg ());
        break; // DATA is the last header entry, everything after it will be interpreted as point cloud data
      }

For reference: https://pcl.readthedocs.io/projects/tutorials/en/master/pcd_file_format.html

@mvieth Thank you for your suggestion! I have changed it to your version.

[mvieth]

Thanks!