How to interpret PointCloud2 data?

[ahar]

Hi,
I use this package for generating pointcloud corresponding to the laser range data. range data is of float32 type where as PointCloud2 data is uint8 type and therefore it is confusing for me to interpret as to which range measurement corresponds to which data of the cloud.

Again, from the structure of the cloud, I find that the sequence of data repeats after every 16 data field, in which last four remain zeros. The remaining 12 represent one point corresponding to a range measurement. Am I right? Now, I do not understand which ones are the x , y and z values in this.
Please help me to interpret it correctly, as I need to do some sensor calibration using this data.