dfilter: Add support for raw strings

Add support for a literal string specification copied from Python
raw strings[1].

Raw string literals are enclosed with r"..." or R"...". Double quotes
can be include in the string but they must be escaped with backslash.
In escape sequences backslashes are preserved in the final result.

So for example the string "a\\\"b" is the same as r"a\"b".

r"\\\a" is the same as "\\\\\\a".

Raw strings should be used for convenience wherever a regular expression
is used in a display filter expression.

[1]https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals

1 files changed, 1 insertions, 0 deletions

diff --git a/epan/dfilter/dfilter-int.h b/epan/dfilter/dfilter-int.h
index 9d53353954..648892aed6 100644
--- a/epan/dfilter/dfilter-int.h
+++ b/epan/dfilter/dfilter-int.h
@@ -50,6 +50,7 @@ typedef struct {
 typedef struct {
 	dfwork_t *dfw;
 	GString* quoted_string;
+	gboolean raw_string;
 	gboolean in_set;	/* true if parsing set elements for the membership operator */
 } df_scanner_state_t;