component_information: switch from gzip to xz

Improves compression, e.g. current params file: 62KB to 51KB

There's also a PRESET_EXTREME option, which reduces by another 2KB.
We can revisit that once needed, as it increases mem usage as well.

src/lib/parameters/CMakeLists.txt

@@ -89,7 +89,7 @@ add_custom_command(OUTPUT ${generated_serial_params_file}
 set(parameters_xml ${PX4_BINARY_DIR}/parameters.xml)
 set(parameters_json ${PX4_BINARY_DIR}/params.json) # file name needs to be kept short to fit into url (metadata_uri)
 file(GLOB_RECURSE param_src_files ${PX4_SOURCE_DIR}/src/*params.c)
-add_custom_command(OUTPUT ${parameters_xml} ${parameters_json} ${parameters_json}.gz
+add_custom_command(OUTPUT ${parameters_xml} ${parameters_json} ${parameters_json}.xz
 	COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/px_process_params.py
 		--src-path ${module_list} ${generated_params_dir}
 		--xml ${parameters_xml}

src/lib/parameters/px_process_params.py

@@ -49,15 +49,15 @@ import os
 import argparse
 from px4params import srcscanner, srcparser, injectxmlparams, xmlout, markdownout, jsonout
 
-import gzip #to create .gz file
+import lzma #to create .xz file
 import re
 import json
 import codecs
 
-def SaveCompressed(filename):
-    #create gz compressed version
-    gz_filename=filename+'.gz'
-    with gzip.open(gz_filename, 'wt') as f:
+def save_compressed(filename):
+    #create lzma compressed version
+    xz_filename=filename+'.xz'
+    with lzma.open(xz_filename, 'wt', preset=9) as f:
         with open(filename, 'r') as content_file:
             f.write(content_file.read())
 
@@ -185,7 +185,7 @@ def main():
         for f in output_files:
             if args.verbose:
                 print("Compressing file " + f)
-            SaveCompressed(f)
+            save_compressed(f)
             
 
 if __name__ == "__main__":