dfilter: Optimize some scanner patterns

Cleanup flex code. Optimize some patterns to avoid lookups
for field matches for values that are not legal field names.

Improve warning and add some comments.

1 files changed, 16 insertions, 1 deletions

diff --git a/test/suite_dfilter/group_syntax.py b/test/suite_dfilter/group_syntax.py
index a2494ae84f..77762fb8ea 100644
--- a/test/suite_dfilter/group_syntax.py
+++ b/test/suite_dfilter/group_syntax.py
@@ -193,11 +193,26 @@ class case_equality(unittest.TestCase):
         dfilter = 'frame[37] == fc:'
         checkDFilterCount(dfilter, 1)
 
-    def test_rhs_literal_bias_4(self, checkDFilterCount):
+    def test_rhs_bias_4(self, checkDFilterCount):
         # Protocol "Fibre Channel" on the RHS
         dfilter = 'frame[37] == .fc'
         checkDFilterCount(dfilter, 0)
 
+    def test_rhs_bias_5(self, checkDFilterSucceed):
+        # Protocol "Fibre Channel" on the RHS (with warning)
+        dfilter = 'frame contains fc'
+        checkDFilterSucceed(dfilter, 'Interpreting "fc" as Fibre Channel')
+
+    def test_rhs_bias_6(self, checkDFilterSucceed):
+        # Protocol "Fibre Channel" on the RHS (without warning)
+        dfilter = 'frame contains .fc'
+        checkDFilterSucceed(dfilter)
+
+    def test_rhs_bias_7(self, checkDFilterSucceed):
+        # Byte 0xFC on the RHS
+        dfilter = 'frame contains fc:'
+        checkDFilterSucceed(dfilter)
+
 @fixtures.uses_fixtures
 class case_bitwise(unittest.TestCase):
     trace_file = "http.pcap"