replace struct pack/unpack with bitops

Author: lipp

Dockerfile

@@ -0,0 +1,33 @@
+FROM ubuntu:14.04
+# install autobahn tests suite (python)
+RUN apt-get update -y && apt-get install build-essential libffi-dev libssl-dev python-pip -y
+RUN apt-get install python-dev -y
+RUN pip -V
+RUN pip install autobahntestsuite
+# install lua
+ENV LUAROCKS_VERSION=2.0.13
+ENV LUAROCKS_BASE=luarocks-$LUAROCKS_VERSION
+ENV LUA luajit
+ENV LUA_DEV libluajit-5.1-dev 
+ENV LUA_VER 5.1
+ENV LUA_SFX jit
+ENV LUA_INCDIR /usr/include/luajit-2.0
+
+#    - LUA=lua5.1 LUA_DEV=liblua5.1-dev LUA_VER=5.1 LUA_SFX=5.1 LUA_INCDIR=/usr/include/lua5.1
+#   - LUA=lua5.2 LUA_DEV=liblua5.2-dev LUA_VER=5.2 LUA_SFX=5.2 LUA_INCDIR=/usr/include/lua5.2
+#   - LUA=luajit LUA_DEV=libluajit-5.1-dev LUA_VER=5.1 LUA_SFX=jit LUA_INCDIR=/usr/include/luajit-2.0
+RUN apt-get install ${LUA} ${LUA_DEV} wget libev-dev git-core unzip -y
+RUN lua${LUA_SFX} -v
+RUN wget --quiet https://github.com/keplerproject/luarocks/archive/v$LUAROCKS_VERSION.tar.gz -O $LUAROCKS_BASE.tar.gz
+RUN tar zxpf $LUAROCKS_BASE.tar.gz
+RUN cd $LUAROCKS_BASE && ./configure --lua-version=$LUA_VER --lua-suffix=$LUA_SFX --with-lua-include="$LUA_INCDIR" && make install && cd ..
+RUN luarocks --version
+RUN git clone http://github.com/brimworks/lua-ev && cd lua-ev && luarocks make LIBEV_LIBDIR=/usr/lib/x86_64-linux-gnu/ rockspec/lua-ev-scm-1.rockspec && cd ..
+RUN luarocks install LuaCov
+RUN luarocks install lua_cliargs 2.3-3
+RUN luarocks install busted 1.10.0-1
+ADD . /lua-websockets
+WORKDIR /lua-websockets
+RUN luarocks make rockspecs/lua-websockets-scm-1.rockspec 
+RUN ./test.sh
+

README.md

@@ -115,9 +115,7 @@ var echoWs = new WebSocket('ws://127.0.0.1:8002','echo');
 The client and server modules depend on:
 
   - luasocket
-  - struct
   - luabitop (if not using Lua 5.2 nor luajit)
-  - luacrypto (optionally)
   - copas (optionally)
   - lua-ev (optionally)
 

lua-websockets.rockspec

@@ -10,12 +10,11 @@ description = {
   summary = "Websockets for Lua",
   homepage = "http://github.com/lipp/lua-websockets",
   license = "MIT/X11",
-  detailed = "Provides sync and async clients and servers for copas."
+  detailed = "Provides sync and async clients and servers for copas and lua-ev."
 }
 
 dependencies = {
   "lua >= 5.1",
-  "struct",
   "luasocket",
   "luabitop",
   "copas"

rockspecs/lua-websockets-scm-1.rockspec

@@ -14,7 +14,6 @@ description = {
 
 dependencies = {
   "lua >= 5.1",
-  "struct",
   "luasocket",
   "luabitop",
   "lua-ev",

src/websocket/frame.lua

@@ -1,5 +1,4 @@
 -- Following Websocket RFC: http://tools.ietf.org/html/rfc6455
-local struct = require'struct'
 local bit = require'websocket.bit'
 local band = bit.band
 local bxor = bit.bxor
@@ -12,11 +11,16 @@ local schar = string.char
 local tinsert = table.insert
 local tconcat = table.concat
 local mmin = math.min
-local strpack = struct.pack
-local strunpack = struct.unpack
 local mfloor = math.floor
 local mrandom = math.random
 local unpack = unpack or table.unpack
+local tools = require'websocket.tools'
+local write_int8 = tools.write_int8
+local write_int16 = tools.write_int16
+local write_int32 = tools.write_int32
+local read_int8 = tools.read_int8
+local read_int16 = tools.read_int16
+local read_int32 = tools.read_int32
 
 local bits = function(...)
   local n = 0
@@ -30,6 +34,7 @@ local bit_7 = bits(7)
 local bit_0_3 = bits(0,1,2,3)
 local bit_0_6 = bits(0,1,2,3,4,5,6)
 
+-- TODO: improve performance
 local xor_mask = function(encoded,mask,payload)
   local transformed,transformed_arr = {},{}
   -- xor chunk-wise to prevent stack overflow.
@@ -49,7 +54,6 @@ local xor_mask = function(encoded,mask,payload)
 end
 
 local encode = function(data,opcode,masked,fin)
-  local encoded
   local header = opcode or 1-- TEXT is default opcode
   if fin == nil or fin == true then
     header = bor(header,bit_7)
@@ -59,41 +63,44 @@ local encode = function(data,opcode,masked,fin)
     payload = bor(payload,bit_7)
   end
   local len = #data
+  local chunks = {}
   if len < 126 then
     payload = bor(payload,len)
-    encoded = strpack('bb',header,payload)
+    tinsert(chunks,write_int8(header,payload))
   elseif len <= 0xffff then
     payload = bor(payload,126)
-    encoded = strpack('bb>H',header,payload,len)
+    tinsert(chunks,write_int8(header,payload))
+    tinsert(chunks,write_int16(len))
   elseif len < 2^53 then
     local high = mfloor(len/2^32)
     local low = len - high*2^32
     payload = bor(payload,127)
-    encoded = strpack('bb>I>I',header,payload,high,low)
+    tinsert(chunks,write_int8(header,payload))
+    tinsert(chunks,write_int32(high))
+    tinsert(chunks,write_int32(low))
   end
   if not masked then
-    encoded = encoded..data
+    tinsert(chunks,data)
   else
     local m1 = mrandom(0,0xff)
     local m2 = mrandom(0,0xff)
     local m3 = mrandom(0,0xff)
     local m4 = mrandom(0,0xff)
     local mask = {m1,m2,m3,m4}
-    encoded = tconcat({
-        encoded,
-        strpack('BBBB',m1,m2,m3,m4),
-        xor_mask(data,mask,#data)
-    })
+    tinsert(chunks,write_int8(m1,m2,m3,m4))
+    tinsert(chunks,xor_mask(data,mask,#data))
   end
-  return encoded
+  return tconcat(chunks)
 end
 
 local decode = function(encoded)
   local encoded_bak = encoded
   if #encoded < 2 then
     return nil,2-#encoded
   end
-  local header,payload,pos = strunpack('bb',encoded)
+  local pos,header,payload
+  pos,header = read_int8(encoded,1)
+  pos,payload = read_int8(encoded,pos)
   local high,low
   encoded = ssub(encoded,pos)
   local bytes = 2
@@ -106,12 +113,13 @@ local decode = function(encoded)
       if #encoded < 2 then
         return nil,2-#encoded
       end
-      payload,pos = strunpack('>H',encoded)
+      pos,payload = read_int16(encoded,1)
     elseif payload == 127 then
       if #encoded < 8 then
         return nil,8-#encoded
       end
-      high,low,pos = strunpack('>I>I',encoded)
+      pos,high = read_int32(encoded,1)
+      pos,low = read_int32(encoded,pos)
       payload = high*2^32 + low
       if payload < 0xffff or payload > 2^53 then
         assert(false,'INVALID PAYLOAD '..payload)
@@ -128,7 +136,11 @@ local decode = function(encoded)
     if bytes_short > 0 then
       return nil,bytes_short
     end
-    local m1,m2,m3,m4,pos = strunpack('BBBB',encoded)
+    local m1,m2,m3,m4
+    pos,m1 = read_int8(encoded,1)
+    pos,m2 = read_int8(encoded,pos)
+    pos,m3 = read_int8(encoded,pos)
+    pos,m4 = read_int8(encoded,pos)
     encoded = ssub(encoded,pos)
     local mask = {
       m1,m2,m3,m4
@@ -152,7 +164,7 @@ end
 
 local encode_close = function(code,reason)
   if code then
-    local data = strpack('>H',code)
+    local data = write_int16(code)
     if reason then
       data = data..tostring(reason)
     end
@@ -165,7 +177,7 @@ local decode_close = function(data)
   local _,code,reason
   if data then
     if #data > 1 then
-      code = strunpack('>H',data)
+      _,code = read_int16(data,1)
     end
     if #data > 2 then
       reason = data:sub(3)

src/websocket/tools.lua

@@ -1,4 +1,3 @@
-local struct = require'struct'
 local bit = require'websocket.bit'
 local rol = bit.rol
 local bxor = bit.bxor
@@ -15,6 +14,46 @@ local tinsert = table.insert
 local tconcat = table.concat
 local mrandom = math.random
 
+local read_n_bytes = function(str, pos, n)
+  pos = pos or 1
+  return pos+n, string.byte(str, pos, pos + n - 1)
+end
+
+local read_int8 = function(str, pos)
+  return read_n_bytes(str, pos, 1)
+end
+
+local read_int16 = function(str, pos)
+  local new_pos,a,b = read_n_bytes(str, pos, 2)
+  return new_pos, lshift(a, 8) + b
+end
+
+local read_int32 = function(str, pos)
+  local new_pos,a,b,c,d = read_n_bytes(str, pos, 4)
+  return new_pos,
+  lshift(a, 24) +
+  lshift(b, 16) +
+  lshift(c, 8 ) +
+  d
+end
+
+local pack_bytes = string.char
+
+local write_int8 = pack_bytes
+
+local write_int16 = function(v)
+  return pack_bytes(rshift(v, 8), band(v, 0xFF))
+end
+
+local write_int32 = function(v)
+  return pack_bytes(
+    band(rshift(v, 24), 0xFF),
+    band(rshift(v, 16), 0xFF),
+    band(rshift(v,  8), 0xFF),
+    band(v, 0xFF)
+  )
+end
+
 -- used for generate key random ops
 math.randomseed(os.time())
 
@@ -34,33 +73,37 @@ local sha1_wiki = function(msg)
   local h2 = 0x98BADCFE
   local h3 = 0x10325476
   local h4 = 0xC3D2E1F0
-  
+
   local bits = #msg * 8
   -- append b10000000
   msg = msg..schar(0x80)
-  
+
   -- 64 bit length will be appended
   local bytes = #msg + 8
-  
+
   -- 512 bit append stuff
   local fill_bytes = 64 - (bytes % 64)
   if fill_bytes ~= 64 then
     msg = msg..srep(schar(0),fill_bytes)
   end
-  
+
   -- append 64 big endian length
   local high = math.floor(bits/2^32)
   local low = bits - high*2^32
-  msg = msg..struct.pack('>I>I',high,low)
-  
+  msg = msg..write_int32(high)..write_int32(low)
+
   assert(#msg % 64 == 0,#msg % 64)
-  
+
   for j=1,#msg,64 do
     local chunk = msg:sub(j,j+63)
     assert(#chunk==64,#chunk)
-    local words = {struct.unpack(srep('>I',16),chunk)}
-    -- last item contains the index in chunk where it stopped reading
-    tremove(words,17)
+    local words = {}
+    local next = 1
+    local word
+    repeat
+      next,word = read_int32(chunk, next)
+      tinsert(words, word)
+    until next > 64
     assert(#words==16)
     for i=17,80 do
       words[i] = bxor(words[i-3],words[i-8],words[i-14],words[i-16])
@@ -71,7 +114,7 @@ local sha1_wiki = function(msg)
     local c = h2
     local d = h3
     local e = h4
-    
+
     for i=1,80 do
       local k,f
       if i > 0 and i < 21 then
@@ -87,31 +130,31 @@ local sha1_wiki = function(msg)
         f = bxor(b,c,d)
         k = 0xCA62C1D6
       end
-      
+
       local temp = rol(a,5) + f + e + k + words[i]
       e = d
       d = c
       c = rol(b,30)
       b = a
       a = temp
     end
-    
+
     h0 = h0 + a
     h1 = h1 + b
     h2 = h2 + c
     h3 = h3 + d
     h4 = h4 + e
-    
+
   end
-  
+
   -- necessary on sizeof(int) == 32 machines
   h0 = band(h0,0xffffffff)
   h1 = band(h1,0xffffffff)
   h2 = band(h2,0xffffffff)
   h3 = band(h3,0xffffffff)
   h4 = band(h4,0xffffffff)
-  
-  return struct.pack('>i>i>i>i>i',h0,h1,h2,h3,h4)
+
+  return write_int32(h0)..write_int32(h1)..write_int32(h2)..write_int32(h3)..write_int32(h4)
 end
 
 local base64_encode = function(data)
@@ -139,7 +182,7 @@ local generate_key = function()
   local r2 = mrandom(0,0xfffffff)
   local r3 = mrandom(0,0xfffffff)
   local r4 = mrandom(0,0xfffffff)
-  local key = struct.pack('IIII',r1,r2,r3,r4)
+  local key = write_int32(r1)..write_int32(r2)..write_int32(r3)..write_int32(r4)
   assert(#key==16,#key)
   return base64_encode(key)
 end
@@ -151,4 +194,10 @@ return {
   },
   parse_url = parse_url,
   generate_key = generate_key,
+  read_int8 = read_int8,
+  read_int16 = read_int16,
+  read_int32 = read_int32,
+  write_int8 = write_int8,
+  write_int16 = write_int16,
+  write_int32 = write_int32,
 }