diff --git a/nse_main.cc b/nse_main.cc
index a93d456..e2bba66 100644
--- a/nse_main.cc
+++ b/nse_main.cc
@@ -236,6 +236,35 @@ static int l_xml_newline(lua_State *L)
   return 0;
 }
 
+static int l_tcopy_helper(lua_State *L, int idx=1)
+{
+  idx = lua_absindex(L, idx);
+  lua_newtable(L);
+  lua_pushnil(L);
+  while (lua_next(L, idx) != 0) {
+    /* -3 = new table, -2 = key, -1 = value */
+    if (lua_istable(L, -1)) {
+      lua_pushvalue(L, -2);
+      l_tcopy_helper(L, -2); /* pushes copy of table to top (value) of stack */
+      lua_rawset(L, -5);
+      lua_pop(L, 1);
+    }
+    else {
+      lua_pushvalue(L, -2);
+      lua_pushvalue(L, -2);
+      lua_rawset(L, -5);
+      lua_pop(L, 1);
+    }
+  }
+  return 1;
+}
+/* (0, +1) */
+static int l_tcopy(lua_State *L)
+{
+    return l_tcopy_helper(L, 1);
+}
+
+
 static void open_cnse (lua_State *L)
 {
   static const luaL_Reg nse[] = {
@@ -253,6 +282,7 @@ static void open_cnse (lua_State *L)
     {"xml_end_tag", l_xml_end_tag},
     {"xml_write_escaped", l_xml_write_escaped},
     {"xml_newline", l_xml_newline},
+    {"tcopy", l_tcopy},
     {NULL, NULL}
   };
 
diff --git a/nse_main.lua b/nse_main.lua
index 819ef6c..36aca00 100644
--- a/nse_main.lua
+++ b/nse_main.lua
@@ -227,18 +227,7 @@ local function loadscript (filename)
 end
 
 -- recursively copy a table, for host/port tables
--- not very rigorous, but it doesn't need to be
-local function tcopy (t)
-  local tc = {};
-  for k,v in pairs(t) do
-    if type(v) == "table" then
-      tc[k] = tcopy(v);
-    else
-      tc[k] = v;
-    end
-  end
-  return tc;
-end
+local tcopy = cnse.tcopy
 
 -- copies the host table while preserving the registry
 local function host_copy(t)
diff --git a/nselib/http.lua b/nselib/http.lua
index aedde98..d86d711 100644
--- a/nselib/http.lua
+++ b/nselib/http.lua
@@ -244,16 +244,12 @@ end
 local function skip_lws(s, pos)
   local _, e
 
-  while true do
-    while string.match(s, "^[ \t]", pos) do
-      pos = pos + 1
-    end
-    _, e = string.find(s, "^\r?\n[ \t]", pos)
-    if not e then
-      return pos
-    end
+  _, e = string.find(s, "^[ \t]*", pos)
+  while e do
     pos = e + 1
+    _, e = string.find(s, "^\r?\n[ \t]+", pos)
   end
+  return pos
 end
 
 
@@ -643,14 +639,15 @@ local function parse_header(header, response)
   local pos
   local name, words
   local s, e
+  local header_len = #header
 
   response.header = {}
   response.rawheader = stdnse.strsplit("\r?\n", header)
   pos = 1
-  while pos <= #header do
+  while pos <= header_len do
     -- Get the field name.
     e, name = get_token(header, pos)
-    if not name or e > #header or string.sub(header, e, e) ~= ":" then
+    if not name or e > header_len or string.sub(header, e, e) ~= ":" then
       return nil, string.format("Can't get header field name at %q", string.sub(header, pos, pos + 30))
     end
     pos = e + 1
@@ -659,14 +656,10 @@ local function parse_header(header, response)
     pos = skip_lws(header, pos)
     -- Get non-space words separated by LWS, then join them with a single space.
     words = {}
-    while pos <= #header and not string.match(header, "^\r?\n", pos) do
-      s = pos
-      while not string.match(header, "^[ \t]", pos) and
-        not string.match(header, "^\r?\n", pos) do
-        pos = pos + 1
-      end
-      words[#words + 1] = string.sub(header, s, pos - 1)
-      pos = skip_lws(header, pos)
+    while pos <= header_len and not string.match(header, "^\r?\n", pos) do
+      s, e = string.find(header, "^[^%s]*", pos)
+      words[#words + 1] = string.sub(header, s, e)
+      pos = skip_lws(header, e+1)
     end
 
     -- Set it in our table.