Adds support for Lua struct library so one can pack/unpack binary structures

This is based on Roberto Ierusalimschy's struct library, along with additional
options based on Flemming Madsen's patch to the lua-users mailing list, and
some changes I made to support 64-bit integer packing/unpacking.  Details
are in the top comments for wslua_struct.c.  This also includes a test script.

Change-Id: Ifcd0116ba013d5c760927721c8d6e9f28965534b
Reviewed-on: https://code.wireshark.org/review/98
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Alexis La Goutte <alexis.lagoutte@gmail.com>

1 files changed, 339 insertions, 0 deletions

diff --git a/test/lua/struct.lua b/test/lua/struct.lua
new file mode 100644
index 0000000000..9ff0d59dd3
--- /dev/null
+++ b/test/lua/struct.lua
@@ -0,0 +1,339 @@
+
+-- This is a test script for tshark/wireshark.
+-- This script runs inside tshark/wireshark, so to run it do:
+-- wireshark -X lua_script:<path_to_testdir>/lua/struct.lua
+-- tshark -r bogus.cap -X lua_script:<path_to_testdir>/lua/struct.lua
+
+-- Tests Int64/UInt64 functions
+
+local function testing(...)
+	print("---- Testing "..tostring(...).." ----")
+end
+
+local function test(name, ...)
+	io.stdout:write("test "..name.."...")
+	if (...) == true then
+		io.stdout:write("passed\n")
+	else
+		io.stdout:write("failed!\n")
+		error(name.." test failed!")
+	end
+end
+--
+-- auxiliar function to print an hexadecimal `dump' of a given string
+-- (not used by the test)
+--
+local function bp (s)
+  s = string.gsub(s, "(.)", function(c)
+        return string.format("\\%02x", string.byte(c))
+      end)
+  print(s)
+end
+
+
+-----------------------------
+
+print("Lua version: ".._VERSION)
+
+testing("Struct library")
+
+local lib = Struct
+test("global",_G.Struct == lib)
+
+for name, val in pairs(lib) do
+	print("\t"..name.." = "..type(val))
+end
+
+test("class1",type(lib) == 'table')
+test("class2",type(lib.pack) == 'function')
+test("class3",type(lib.unpack) == 'function')
+test("class4",type(lib.size) == 'function')
+
+
+local val1 = "\42\00\00\00\00\00\00\01\00\00\00\02\00\00\00\03\00\00\00\04"
+local fmt1_le = "<!4biii4i4"
+local fmt1_be = ">!4biii4i4"
+local fmt1_64le = "<!4ieE"
+local fmt1_64be = ">!4ieE"
+local fmt2_be = ">!4bi(ii4)i"
+
+testing("basic size")
+
+test("basic_size1", lib.size(fmt1_le) == string.len(val1))
+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("basic unpack")
+local ret1, ret2, ret3, ret4, ret5, pos = lib.unpack(fmt1_le, val1)
+test("basic_unpack1", ret1 == 42 and ret2 == 0x01000000 and ret3 == 0x02000000 and ret4 == 0x03000000 and ret5 == 0x04000000)
+test("basic_unpack_position1", pos == string.len(val1) + 1)
+
+ret1, ret2, ret3, ret4, ret5, pos = lib.unpack(fmt1_be, val1)
+test("basic_unpack2", ret1 == 42 and ret2 == 1 and ret3 == 2 and ret4 == 3 and ret5 == 4)
+test("basic_unpack_position2", pos == string.len(val1) + 1)
+
+ret1, ret2, ret3, pos = lib.unpack(fmt1_64le, val1)
+test("basic_unpack3", ret1 == 42 and ret2 == Int64.new( 0x01000000, 0x02000000) and ret3 == UInt64.new( 0x03000000, 0x04000000))
+print(typeof(ret2),typeof(ret3))
+test("basic_unpack3b", typeof(ret2) == "Int64" and typeof(ret3) == "UInt64")
+test("basic_unpack_position3", pos == string.len(val1) + 1)
+
+ret1, ret2, ret3, pos = lib.unpack(fmt1_64be, val1)
+test("basic_unpack4", ret1 == 0x2A000000 and ret2 == Int64.new( 2, 1) and ret3 == UInt64.new( 4, 3))
+test("basic_unpack4b", typeof(ret2) == "Int64" and typeof(ret3) == "UInt64")
+test("basic_unpack_position4", pos == string.len(val1) + 1)
+
+ret1, ret2, ret3, pos = lib.unpack(fmt2_be, val1)
+test("basic_unpack5", ret1 == 42 and ret2 == 1 and ret3 == 4)
+test("basic_unpack_position5", pos == string.len(val1) + 1)
+
+testing("basic pack")
+local pval1 = lib.pack(fmt1_le, lib.unpack(fmt1_le, val1))
+test("basic_pack1", pval1 == val1)
+test("basic_pack2", val1 == lib.pack(fmt1_be, lib.unpack(fmt1_be, val1)))
+test("basic_pack3", val1 == lib.pack(fmt1_64le, lib.unpack(fmt1_64le, val1)))
+test("basic_pack4", val1 == lib.pack(fmt1_64be, lib.unpack(fmt1_64be, val1)))
+test("basic_pack5", lib.pack(fmt2_be, lib.unpack(fmt1_be, val1)) == lib.pack(">!4biiii", 42, 1, 0, 0, 2))
+
+----------------------------------
+-- following comes from:
+-- http://www.inf.puc-rio.br/~roberto/struct/teststruct
+-- unfortunately many of his tests assumed a local machine word
+-- size of 4 bytes for long and such, so I had to muck with this
+-- to make it handle 64-bit compiles.
+-- $Id: teststruct.lua,v 1.2 2008/04/18 20:06:01 roberto Exp $
+
+
+-- some pack/unpack commands are host-size dependent, so we need to pad
+local l_pad, ln_pad = "",""
+if lib.size("l") == 8 then
+	-- the machine running this script uses a long of 8 bytes
+	l_pad = "\00\00\00\00"
+	ln_pad = "\255\255\255\255"
+end
+
+local a,b,c,d,e,f,x
+
+testing("pack")
+test("pack_I",#Struct.pack("I", 67324752) == 4)
+
+test("pack_b1",lib.pack('b', 10) == string.char(10))
+test("pack_b2",lib.pack('bbb', 10, 20, 30) == string.char(10, 20, 30))
+
+test("pack_h1",lib.pack('<h', 10) == string.char(10, 0))
+test("pack_h2",lib.pack('>h', 10) == string.char(0, 10))
+test("pack_h3",lib.pack('<h', -10) == string.char(256-10, 256-1))
+
+test("pack_l1",lib.pack('<l', 10) == string.char(10, 0, 0, 0)..l_pad)
+test("pack_l2",lib.pack('>l', 10) == l_pad..string.char(0, 0, 0, 10))
+test("pack_l3",lib.pack('<l', -10) == string.char(256-10, 256-1, 256-1, 256-1)..ln_pad)
+
+testing("unpack")
+test("unpack_h1",lib.unpack('<h', string.char(10, 0)) == 10)
+test("unpack_h2",lib.unpack('>h', string.char(0, 10)) == 10)
+test("unpack_h3",lib.unpack('<h', string.char(256-10, 256-1)) == -10)
+
+test("unpack_l1",lib.unpack('<l', string.char(10, 0, 0, 1)..l_pad) == 10 + 2^(3*8))
+test("unpack_l2",lib.unpack('>l', l_pad..string.char(0, 1, 0, 10)) == 10 + 2^(2*8))
+test("unpack_l3",lib.unpack('<l', string.char(256-10, 256-1, 256-1, 256-1)..ln_pad) == -10)
+
+-- limits
+lims = {{'B', 255}, {'b', 127}, {'b', -128},
+        {'I1', 255}, {'i1', 127}, {'i1', -128},
+        {'H', 2^16 - 1}, {'h', 2^15 - 1}, {'h', -2^15},
+        {'I2', 2^16 - 1}, {'i2', 2^15 - 1}, {'i2', -2^15},
+        {'L', 2^32 - 1}, {'l', 2^31 - 1}, {'l', -2^31},
+        {'I4', 2^32 - 1}, {'i4', 2^31 - 1}, {'i4', -2^31},
+       }
+
+for _, a in pairs{'', '>', '<'} do
+  local i = 1
+  for _, l in pairs(lims) do
+    local fmt = a .. l[1]
+    test("limit"..i.."("..l[1]..")", lib.unpack(fmt, lib.pack(fmt, l[2])) == l[2])
+    i = i + 1
+  end
+end
+
+
+testing("fixed-sized ints")
+-- tests for fixed-sized ints
+local num = 1
+for _, i in pairs{1,2,4} do
+  x = lib.pack('<i'..i, -3)
+  test("pack_fixedlen"..num, string.len(x) == i)
+  test("pack_fixed"..num, x == string.char(256-3) .. string.rep(string.char(256-1), i-1))
+  test("unpack_fixed"..num, lib.unpack('<i'..i, x) == -3)
+  num = num + 1
+end
+
+
+testing("alignment")
+-- alignment
+d = lib.pack("d", 5.1)
+ali = {[1] = string.char(1)..d,
+       [2] = string.char(1, 0)..d,
+       [4] = string.char(1, 0, 0, 0)..d,
+       [8] = string.char(1, 0, 0, 0, 0, 0, 0, 0)..d,
+      }
+
+num = 1
+for a,r in pairs(ali) do
+  test("pack_align"..num, lib.pack("!"..a.."bd", 1, 5.1) == r)
+  local x,y = lib.unpack("!"..a.."bd", r)
+  test("unpack_align"..num, x == 1 and y == 5.1)
+  num = num + 1
+end
+
+
+testing("string")
+-- strings
+test("string_pack1",lib.pack("c", "alo alo") == "a")
+test("string_pack2",lib.pack("c4", "alo alo") == "alo ")
+test("string_pack3",lib.pack("c5", "alo alo") == "alo a")
+test("string_pack4",lib.pack("!4b>c7", 1, "alo alo") == "\1alo alo")
+test("string_pack5",lib.pack("!2<s", "alo alo") == "alo alo\0")
+test("string_pack6",lib.pack(" c0 ", "alo alo") == "alo alo")
+num = 1
+for _, f in pairs{"B", "l", "i2", "f", "d"} do
+  for _, s in pairs{"", "a", "alo", string.rep("x", 200)} do
+    local x = lib.pack(f.."c0", #s, s)
+    test("string_unpack"..num, lib.unpack(f.."c0", x) == s)
+    num = num + 1
+  end
+end
+
+
+testing("indeces")
+-- indices
+x = lib.pack("!>iiiii", 1, 2, 3, 4, 5)
+local i = 1
+local k = 1
+num = 1
+while i < #x do
+  local v, j = lib.unpack("!>i", x, i)
+  test("index_unpack"..num, j == i + 4 and v == k)
+  i = j; k = k + 1
+  num = num + 1
+end
+
+testing("absolute")
+-- alignments are relative to 'absolute' positions
+x = lib.pack("!8 xd", 12)
+test("absolute_unpack1",lib.unpack("!8d", x, 3) == 12)
+
+
+test("absolute_pack1",lib.pack("<lhbxxH", -2, 10, -10, 250) ==
+  string.char(254, 255, 255, 255) ..ln_pad.. string.char(10, 0, 246, 0, 0, 250, 0))
+
+a,b,c,d = lib.unpack("<lhbxxH",
+  string.char(254, 255, 255, 255) ..ln_pad.. string.char(10, 0, 246, 0, 0, 250, 0))
+test("absolute_unpack2",a == -2 and b == 10 and c == -10 and d == 250)
+
+test("absolute_pack2",lib.pack(">lBxxH", -20, 10, 250) ==
+                ln_pad..string.char(255, 255, 255, 236, 10, 0, 0, 0, 250))
+
+
+testing("position")
+
+a, b, c, d = lib.unpack(">lBxxH",
+                 ln_pad..string.char(255, 255, 255, 236, 10, 0, 0, 0, 250))
+-- the 'd' return val is position in string, so will depend on size of long 'l'
+local vald = 10 + string.len(l_pad)
+test("position_unpack1",a == -20 and b == 10 and c == 250 and d == vald)
+
+a,b,c,d,e = lib.unpack(">fdfH",
+                  '000'..lib.pack(">fdfH", 3.5, -24e-5, 200.5, 30000),
+                  4)
+test("position_unpack2",a == 3.5 and b == -24e-5 and c == 200.5 and d == 30000 and e == 22)
+
+a,b,c,d,e = lib.unpack("<fdxxfH",
+                  '000'..lib.pack("<fdxxfH", -13.5, 24e5, 200.5, 300),
+                  4)
+test("position_unpack3",a == -13.5 and b == 24e5 and c == 200.5 and d == 300 and e == 24)
+
+x = lib.pack(">I2fi4I2", 10, 20, -30, 40001)
+test("position_pack1",string.len(x) == 2+4+4+2)
+test("position_unpack4",lib.unpack(">f", x, 3) == 20)
+a,b,c,d = lib.unpack(">i2fi4I2", x)
+test("position_unpack5",a == 10 and b == 20 and c == -30 and d == 40001)
+
+testing("string length")
+local s = "hello hello"
+x = lib.pack(" b c0 ", string.len(s), s)
+test("stringlen_unpack1",lib.unpack("bc0", x) == s)
+x = lib.pack("Lc0", string.len(s), s)
+test("stringlen_unpack2",lib.unpack("  L  c0   ", x) == s)
+x = lib.pack("cc3b", s, s, 0)
+test("stringlen_pack1",x == "hhel\0")
+test("stringlen_unpack3",lib.unpack("xxxxb", x) == 0)
+
+testing("padding")
+test("padding_pack1",lib.pack("<!l", 3) == string.char(3, 0, 0, 0)..l_pad)
+test("padding_pack2",lib.pack("<!xl", 3) == l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad)
+test("padding_pack3",lib.pack("<!xxl", 3) == l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad)
+test("padding_pack4",lib.pack("<!xxxl", 3) == l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad)
+
+test("padding_unpack1",lib.unpack("<!l", string.char(3, 0, 0, 0)..l_pad) == 3)
+test("padding_unpack2",lib.unpack("<!xl", l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad) == 3)
+test("padding_unpack3",lib.unpack("<!xxl", l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad) == 3)
+test("padding_unpack4",lib.unpack("<!xxxl", l_pad..string.char(0, 0, 0, 0, 3, 0, 0, 0)..l_pad) == 3)
+
+testing("format")
+test("format_pack1",lib.pack("<!2 b l h", 2, 3, 5) == string.char(2, 0, 3, 0)..l_pad..string.char(0, 0, 5, 0))
+a,b,c = lib.unpack("<!2blh", string.char(2, 0, 3, 0)..l_pad..string.char(0, 0, 5, 0))
+test("format_pack2",a == 2 and b == 3 and c == 5)
+
+test("format_pack3",lib.pack("<!8blh", 2, 3, 5) == string.char(2, 0, 0, 0)..l_pad..string.char(3, 0, 0, 0)..l_pad..string.char(5, 0))
+
+a,b,c = lib.unpack("<!8blh", string.char(2, 0, 0, 0)..l_pad..string.char(3, 0, 0, 0)..l_pad..string.char(5, 0))
+test("format_pack4",a == 2 and b == 3 and c == 5)
+
+test("format_pack5",lib.pack(">sh", "aloi", 3) == "aloi\0\0\3")
+test("format_pack6",lib.pack(">!sh", "aloi", 3) == "aloi\0\0\0\3")
+
+x = "aloi\0\0\0\0\3\2\0\0"
+a, b, c = lib.unpack("<!si4", x)
+test("format_unpack1",a == "aloi" and b == 2*256+3 and c == string.len(x)+1)
+
+x = lib.pack("!4sss", "hi", "hello", "bye")
+a,b,c = lib.unpack("sss", x)
+test("format_unpack2",a == "hi" and b == "hello" and c == "bye")
+a, i = lib.unpack("s", x, 1)
+test("format_unpack3",a == "hi")
+a, i = lib.unpack("s", x, i)
+test("format_unpack4",a == "hello")
+a, i = lib.unpack("s", x, i)
+test("format_unpack5",a == "bye")
+
+
+
+-- test for weird conditions
+testing("weird conditions")
+test("weird_pack1",lib.pack(">>>h <!!!<h", 10, 10) == string.char(0, 10, 10, 0))
+test("weird_pack2",not pcall(lib.pack, "!3l", 10))
+test("weird_pack3",not pcall(lib.pack, "3", 10))
+test("weird_pack4",not pcall(lib.pack, "i33", 10))
+test("weird_pack5",not pcall(lib.pack, "I33", 10))
+test("weird_pack6",lib.pack("") == "")
+test("weird_pack7",lib.pack("   ") == "")
+test("weird_pack8",lib.pack(">>><<<!!") == "")
+test("weird_unpack1",not pcall(lib.unpack, "c0", "alo"))
+test("weird_unpack2",not pcall(lib.unpack, "s", "alo"))
+test("weird_unpack3",lib.unpack("s", "alo\0") == "alo")
+test("weird_pack9",not pcall(lib.pack, "c4", "alo"))
+test("weird_pack10",pcall(lib.pack, "c3", "alo"))
+test("weird_unpack4",not pcall(lib.unpack, "c4", "alo"))
+test("weird_unpack5",pcall(lib.unpack, "c3", "alo"))
+test("weird_unpack6",not pcall(lib.unpack, "bc0", "\4alo"))
+test("weird_unpack7",pcall(lib.unpack, "bc0", "\3alo"))
+
+test("weird_unpack8",not pcall(lib.unpack, "b", "alo", 4))
+test("weird_unpack9",lib.unpack("b", "alo\3", 4) == 3)
+
+
+print("\n-----------------------------\n")
+
+print("All tests passed!\n\n")