Adds some Lua helper functions: some commonly used functions, and to help troubleshooting Lua scripts

There are some common things people need to do, such as convert to/from hex or get
the raw binary string in a ByteArray/Tvb/TvbRange. These have been added, as well
as some tests for them in the testsuites. Also, functions have been added to allow
a script to get all the available tap types and filter fields, since they are
not exactly what one can see in the Wireshark gui.

Change-Id: I92e5e4eae713bb90d79b0c024eaa4e55b99cc96b
Reviewed-on: https://code.wireshark.org/review/249
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

2 files changed, 23 insertions, 19 deletions

diff --git a/test/lua/dissector.lua b/test/lua/dissector.lua
index 1bff56cfc0..635cdb5d49 100644
--- a/test/lua/dissector.lua
+++ b/test/lua/dissector.lua
@@ -167,7 +167,7 @@ local MYDNS_PROTO_UDP_PORT = 65333
 -- some forward "declarations" of helper functions we use in the dissector
 -- I don't usually use this trick, but it'll help reading/grok'ing this script I think
 -- if we don't focus on them.
-local byteArray2String, getQueryName
+local getQueryName
 
 
 ----------------------------------------
@@ -327,19 +327,6 @@ udp_encap_table:add(MYDNS_PROTO_UDP_PORT, dns)
 ----------------------------------------
 
 ----------------------------------------
--- a helper function used later
--- note that it doesn't use "local" because it's already been declared as a local
--- variable way earlier in this script (as a form of forward declaration)
-byteArray2String = function (barray, begin, length)
-    local word = {}
-    for i = 1, length do
-        word[i] = string.char(barray:get_index(begin))
-        begin = begin + 1
-    end
-    return table.concat(word)
-end
-
-----------------------------------------
 -- DNS query names are not just null-terminated strings; they're actually a sequence of
 -- 'labels', with a length octet before each one.  So "foobar.com" is actually the
 -- string "\06foobar\03com\00".  We could create a ProtoField for label_length and label_name
@@ -373,10 +360,8 @@ getQueryName = function (tvbr)
             return nil, "invalid label length of "..label_len
         end
         pos = pos + 1  -- move past label length octet
-        -- sadly, there's no current way to get a raw Lua string from a ByteArray (nor from Tvb for that matter)
-        -- so we need to do it one character at a a time
         -- append the label and a dot to name string
-        name = name .. byteArray2String(barray, pos, label_len) .. "."
+        name = name .. barray:raw(pos, label_len) .. "."
         len_remaining = len_remaining - (label_len + 1) -- subtract label and its length octet
         label_count = label_count + 1
         pos = pos + label_len -- move past label
diff --git a/test/lua/struct.lua b/test/lua/struct.lua
index 9ff0d59dd3..384e12414e 100644
--- a/test/lua/struct.lua
+++ b/test/lua/struct.lua
@@ -23,10 +23,17 @@ end
 -- auxiliar function to print an hexadecimal `dump' of a given string
 -- (not used by the test)
 --
-local function bp (s)
+local function tohex(s, sep)
+  local patt = "%02x" .. (sep or "")
   s = string.gsub(s, "(.)", function(c)
-        return string.format("\\%02x", string.byte(c))
+        return string.format(patt, string.byte(c))
       end)
+  if sep then s = s:sub(1,-(sep:len()+1)) end
+  return s
+end
+
+local function bp (s)
+  s = tohex(s)
   print(s)
 end
 
@@ -64,6 +71,18 @@ test("basic_size2", lib.size(fmt1_le) == Struct.size(fmt1_be))
 test("basic_size3", lib.size(fmt1_le) == Struct.size(fmt1_64le))
 test("basic_size4", lib.size(fmt2_be) == Struct.size(fmt1_64le))
 
+testing("tohex")
+local val1hex = "2A:00:00:00:00:00:00:01:00:00:00:02:00:00:00:03:00:00:00:04"
+test("tohex1", Struct.tohex(val1) == tohex(val1):upper())
+test("tohex2", Struct.tohex(val1,true) == tohex(val1))
+test("tohex3", Struct.tohex(val1,false,":") == val1hex)
+test("tohex4", Struct.tohex(val1,true,":") == val1hex:lower())
+
+testing("fromhex")
+test("fromhex1", Struct.fromhex(val1hex,":") == val1)
+local val1hex2 = val1hex:gsub(":","")
+test("fromhex2", Struct.fromhex(val1hex2) == val1)
+test("fromhex3", Struct.fromhex(val1hex2:lower()) == val1)
 
 testing("basic unpack")
 local ret1, ret2, ret3, ret4, ret5, pos = lib.unpack(fmt1_le, val1)