;docformat='rst'
;+
;  Create an unzipped copy of a zipped netCDF file, read it, delete the
;    temporary copy, and dereference any pointers in the data structure
;    that has been read before returning it. 
;
; :Author:
;    Bill Barrett
;
; :Params:
;   filename : string
;     the path to the file name to be read
;
; :Keywords:
;   structure : structure
;     an optional structure used to interpret what is read from netcdf
;
; :Examples:
;   To get the data from a level 2a cloud file:
;       retrieval_structure = get_retrieval_structure(!VERSION_2, /cloud)
;       cld_data =  uncompress_and_expand_struct(cld_file, structure=retrieval_structure)
;   To get the data from a level 2a etc file where there is no retrieval structure:
;       etc_data = uncompress_and_expand_struct(etc_file)
;-
function uncompress_and_expand_struct, filename, structure=structure
  ; the 'decompress' function creates a temporary copy of a zipped file.
  ;   while leaving the zipped file unchanged.
  new_filename = decompress(filename)
  read_netcdf, new_filename, data, attributes, status, structure=structure
  ; delete the temporary copy created by 'decompress'
  FILE_DELETE, new_filename
  ; Return a copy of the structure where all pointers have been dereferenced.
  return_data = copy_structure( data, /no_pointers)
  return, return_data
end