add utf8.decode

src/logic/scripting/lua/libs/libutf8.cpp

@@ -5,7 +5,7 @@
 #include "../lua_custom_types.hpp"
 #include "util/stringutil.hpp"
 
-int l_encode(lua::State* L) {
+static int l_encode(lua::State* L) {
     std::string string = lua::require_string(L, 1);
     if (lua::toboolean(L, 2)) {
         lua::createtable(L, string.length(), 0);
@@ -22,7 +22,25 @@ int l_encode(lua::State* L) {
     return 1;
 }
 
+static int l_decode(lua::State* L) {
+    if (lua::istable(L, 1)) {
+        size_t size = lua::objlen(L, 1);
+        util::Buffer<char> buffer(size);
+        return lua::pushstring(L, std::string(buffer.data(), size));
+    } else if (auto bytes = lua::touserdata<lua::LuaBytearray>(L, 1)) {
+        return lua::pushstring(
+            L,
+            std::string(
+                reinterpret_cast<char*>(bytes->data().data()),
+                bytes->data().size()
+            )
+        );
+    }
+    return 1;
+}
+
 const luaL_Reg utf8lib[] = {
     {"encode", lua::wrap<l_encode>},
+    {"decode", lua::wrap<l_decode>},
     {NULL, NULL}
 };