Function treadonly

other_src/lua/src/ltablib.cpp:180–220

#ifdef LUA_READONLY_TABLES
static int treadonly (lua_State *L) {
  static const int luabits = (LUA_READONLY_OLD_LUA_BIT |
                              LUA_READONLY_NEW_LUA_BIT);
  int readonly;

  luaL_checktype(L, 1, LUA_TTABLE);

  readonly = lua_getreadonly(L, 1);

  if (lua_isnone(L, 2)) {  /* read the state */
    if (!readonly) {
      lua_pushboolean(L, 0);
      return 1;
    } else {
      char modes[3], *c = modes;
      if (readonly & LUA_READONLY_OLD_BITS) { *c = 'o'; c++; }
      if (readonly & LUA_READONLY_NEW_BITS) { *c = 'n'; c++; }
      *c = '\0';  /* terminate */
      lua_pushstring(L, modes);
      return 1;
    }
  }

  if (lua_type(L, 2) == LUA_TSTRING) {
    const char *s = lua_tostring(L, 2);
    readonly &= ~luabits;
    if (strchr(s, 'o')) { readonly |= LUA_READONLY_OLD_LUA_BIT; }
    if (strchr(s, 'n')) { readonly |= LUA_READONLY_NEW_LUA_BIT; }
  }
  else {
    if (lua_toboolean(L, 2)) {
      readonly |=  luabits;
    } else {
      readonly &= ~luabits;
    }
  }

  lua_setreadonly(L, 1, readonly);  /* return the table */
  lua_settop(L, 1);
  return 1;
}
#endif