fix-encoding-args.pl: fix terrible performance with large files

"fix-encoding-args.pl epan/dissectors/packet-ieee80211.c" used to take
over 12 seconds to complete. After this change it is reduced to 400ms.
Profiling with Devel::NYTProf showed two issues:
- find_hf_array_entries (5 seconds): matching leading whitespace
  triggers a candidate match against every line. Fix this by removing
  whitespace prior to matching.
- fix_encoding_args_by_hf_type (7.5 seconds): executing 2131 different
  substitution patterns is slow. Fix this by grouping field names and
  execute the substitution only once afterwards (in total 6 calls).

packet-rrc.c is by far the largest file with 215k lines, this used to
take forever (321s) and now completes in 1.3s.

Regression tested by removing "ENC_ASCII" and "ENC_UTF_8" in
dissect_venue_name_info, the expected warnings are still visible.

Change-Id: I071038e8fcb56474ac41223568ce6724258c059d
Reviewed-on: https://code.wireshark.org/review/29789
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

0 files changed, 0 insertions, 0 deletions