experimental optimize canvas:set_data using ffi

res/scripts/stdmin.lua

@@ -1,3 +1,31 @@
+local _ffi = ffi
+ffi = nil
+
+-- Lua has no parallelizm, also _set_data does not call any lua functions so
+-- may be reused one global ffi buffer per lua_State
+local canvas_ffi_buffer
+local canvas_ffi_buffer_size = 0
+
+function __vc_Canvas_set_data(self, data)
+    if type(data) == "cdata" then
+        self:_set_data(tostring(_ffi.cast("uintptr_t", data)))
+    end
+    local width = self.width
+    local height = self.height
+
+    local size = width * height * 4
+    if size > canvas_ffi_buffer_size then
+        canvas_ffi_buffer = _ffi.new(
+            string.format("unsigned char[%s]", size)
+        )
+        canvas_ffi_buffer_size = size
+    end
+    for i=0, size - 1 do
+        canvas_ffi_buffer[i] = data[i + 1]
+    end
+    self:_set_data(tostring(_ffi.cast("uintptr_t", canvas_ffi_buffer)))
+end
+
 -- Check if given table is an array
 function is_array(x)
     if #x > 0 then

src/logic/scripting/lua/lua_engine.cpp

@@ -88,14 +88,17 @@ static void create_libs(State* L, StateType stateType) {
 
 void lua::init_state(State* L, StateType stateType) {
     // Allowed standard libraries
-    pop(L, luaopen_base(L));
-    pop(L, luaopen_math(L));
-    pop(L, luaopen_string(L));
-    pop(L, luaopen_table(L));
-    pop(L, luaopen_debug(L));
-    pop(L, luaopen_jit(L));
-    pop(L, luaopen_bit(L));
-    pop(L, luaopen_os(L));
+    luaL_openlibs(L);
+
+    if (getglobal(L, "require")) {
+        pushstring(L, "ffi");
+        if (call_nothrow(L, 1, 1)) {
+            setglobal(L, "ffi");
+        }
+    }
+    pushnil(L);
+    setglobal(L, "io");
+
     const char* removed_os[] {
         "execute", "exit", "remove", "rename", "setlocale", "tmpname", nullptr};
     remove_lib_funcs(L, "os", removed_os);

src/logic/scripting/lua/lua_util.cpp

@@ -163,20 +163,23 @@ int lua::call(State* L, int argc, int nresults) {
     int handler_pos = gettop(L) - argc;
     pushcfunction(L, l_error_handler);
     insert(L, handler_pos);
+    int top = gettop(L);
     if (lua_pcall(L, argc, nresults, handler_pos)) {
         std::string log = tostring(L, -1);
         pop(L);
         remove(L, handler_pos);
         throw luaerror(log);
     }
+    int added = gettop(L) - (top - argc - 1);
     remove(L, handler_pos);
-    return nresults == -1 ? 1 : nresults;
+    return added;
 }
 
 int lua::call_nothrow(State* L, int argc, int nresults) {
     int handler_pos = gettop(L) - argc;
     pushcfunction(L, l_error_handler);
     insert(L, handler_pos);
+    int top = gettop(L);
     if (lua_pcall(L, argc, -1, handler_pos)) {
         auto errorstr = tostring(L, -1);
         if (errorstr) {
@@ -188,8 +191,9 @@ int lua::call_nothrow(State* L, int argc, int nresults) {
         remove(L, handler_pos);
         return 0;
     }
+    int added = gettop(L) - (top - argc - 1);
     remove(L, handler_pos);
-    return 1;
+    return added;
 }
 
 void lua::dump_stack(State* L) {

src/logic/scripting/lua/lua_wrapper.hpp

@@ -25,7 +25,8 @@ namespace lua {
         if (n < 0) {
             abort();
         }
-        if (lua_gettop(L) < n) {
+        int top = lua_gettop(L);
+        if (top < n) {
             abort();
         }
 #endif
@@ -63,6 +64,9 @@ namespace lua {
     inline void rawseti(lua::State* L, int n, int idx = -2) {
         lua_rawseti(L, idx, n);
     }
+    inline void rawset(lua::State* L, int idx = -3) {
+        lua_rawset(L, idx);
+    }
 
     inline int createtable(lua::State* L, int narr, int nrec) {
         lua_createtable(L, narr, nrec);

src/logic/scripting/lua/usertypes/lua_type_canvas.cpp

@@ -136,6 +136,12 @@ static int l_set_data(State* L) {
     auto& canvas = require_canvas(L, 1);
     auto& image = canvas.data();
     auto data = image.getData();
+
+    if (lua::isstring(L, 2)) {
+        auto ptr = reinterpret_cast<ubyte*>(std::stoull(lua::tostring(L, 2)));
+        std::memcpy(data, ptr, image.getDataSize());
+        return 0;
+    }
     int len = objlen(L, 2);
     if (len < image.getDataSize()) {
         throw std::runtime_error(
@@ -167,7 +173,7 @@ static std::unordered_map<std::string, lua_CFunction> methods {
     {"blit", lua::wrap<l_blit>},
     {"clear", lua::wrap<l_clear>},
     {"update", lua::wrap<l_update>},
-    {"set_data", lua::wrap<l_set_data>},
+    {"_set_data", lua::wrap<l_set_data>},
 };
 
 static int l_meta_index(State* L) {
@@ -189,6 +195,9 @@ static int l_meta_index(State* L) {
         if (!strcmp(name, "height")) {
             return pushinteger(L, data.getHeight());
         }
+        if (!strcmp(name, "set_data")) {
+            return getglobal(L, "__vc_Canvas_set_data");
+        }
         if (auto func = methods.find(tostring(L, 2)); func != methods.end()) {
             return pushcfunction(L, func->second);
         }

src/logic/scripting/scripting.cpp

@@ -120,7 +120,7 @@ std::unique_ptr<Process> scripting::start_coroutine(
         lua::loadbuffer(L, 0, source, script.name());
         if (lua::call(L, 1)) {
             int id = lua::tointeger(L, -1);
-            lua::pop(L, 2);
+            lua::pop(L, 1);
             return std::make_unique<LuaCoroutine>(L, id);
         }
         lua::pop(L);