2 files changed, 18 insertions, 12 deletions

diff --git a/src/lapi.js b/src/lapi.js
index 4b5223a..9c01e95 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -466,15 +466,22 @@ const lua_createtable = function(L, narray, nrec) {
     assert(L.top <= L.ci.top, "stack overflow");
 };
 
-// ignore size argument
-const lua_newuserdata = function(L, size) {
-    let box = Object.create(null);
+const luaS_newudata = function(L, size) {
+    return {
+        metatable: null,
+        uservalue: null,
+        len: size,
+        data: Object.create(null) // ignores size argument
+    };
+};
 
-    L.stack[L.top++] = new lobject.TValue(CT.LUA_TUSERDATA, box);
+const lua_newuserdata = function(L, size) {
+    let u = luaS_newudata(L, size);
+    L.stack[L.top++] = new lobject.TValue(CT.LUA_TUSERDATA, u);
 
     assert(L.top <= L.ci.top, "stack overflow");
 
-    return box;
+    return u.data;
 };
 
 const aux_upvalue = function(L, fi, n) {
@@ -562,8 +569,8 @@ const lua_getmetatable = function(L, objindex) {
 const lua_getuservalue = function(L, idx) {
     let o = index2addr(L, idx);
     assert(L, o.ttisfulluserdata(), "full userdata expected");
-    L.stack[L.top].type = o.type;
-    L.stack[L.top++].value = o.value;
+    let uv = o.uservalue;
+    L.stack[L.top++] = new TValue(uv.type, uv.value);
     assert(L.top <= L.ci.top, "stack overflow");
     return L.stack[L.top - 1].ttnov();
 };
@@ -667,6 +674,7 @@ const lua_touserdata = function(L, idx) {
     let o = index2addr(L, idx);
     switch (o.ttnov()) {
         case CT.LUA_TUSERDATA:
+            return o.value.data;
         case CT.LUA_TLIGHTUSERDATA:
             return o.value;
         default: return null;
@@ -832,12 +840,10 @@ const lua_setuservalue = function(L, idx) {
     assert(1 < L.top - L.ci.funcOff, "not enough elements in the stack");
     let o = index2addr(L, idx);
     assert(L, o.ttisfulluserdata(), "full userdata expected");
-    L.stack[L.top - 1].type = o.type;
-    L.stack[L.top - 1].value = o.value;
-    L.top--;
+    o.uservalue.setfrom(L.stack[L.top - 1]);
+    L.stack[--L.top] = void 0;
 };
 
-
 const lua_callk = function(L, nargs, nresults, ctx, k) {
     assert(k === null || !(L.ci.callstatus & lstate.CIST_LUA), "cannot use continuations inside hooks");
     assert(nargs + 1 < L.top - L.ci.funcOff, "not enough elements in the stack");
diff --git a/src/ltm.js b/src/ltm.js
index 8687eb0..c94d8f1 100644
--- a/src/ltm.js
+++ b/src/ltm.js
@@ -70,7 +70,7 @@ const luaT_init = function(L) {
 const luaT_objtypename = function(L, o) {
     let mt;
     if ((o.ttistable() && (mt = o.metatable) !== null) ||
-        (o.ttisfulluserdata() && (mt = o.metatable) !== null)) {
+        (o.ttisfulluserdata() && (mt = o.value.metatable) !== null)) {
         let name = lobject.table_index(mt, defs.to_luastring('__name', true));
         if (name.ttisstring())
             return name.value;