Function meta_new

library/LuaWrapper.cpp:682–738

* Method: allocation for DF object references. */

 * Method: allocation for DF object references.
 */
static int meta_new(lua_State *state)
{
    int argc = lua_gettop(state);

    if (argc != 1 && argc != 2)
        luaL_error(state, "Usage: object:new() or df.new(object) or df.new(ptype,count)");

    const type_identity *id = get_object_identity(state, 1, "df.new()", true);

    void *ptr = nullptr;
    std::string err_context;

    // Support arrays of primitive types
    if (argc == 2)
    {
        int cnt = luaL_checkint(state, 2);
        if (cnt <= 0)
            luaL_error(state, "Invalid array size in df.new()");
        if (id->type() != IDTYPE_PRIMITIVE)
            luaL_error(state, "Cannot allocate arrays of non-primitive types.");

        size_t sz = id->byte_size() * cnt;
        ptr = malloc(sz);
        if (ptr)
            memset(ptr, 0, sz);
    }
    else
    {
        try {
            ptr = id->allocate();
        }
        catch (std::exception &e) {
            if (e.what()) {
                err_context = e.what();
            }
        }
    }

    if (!ptr)
        luaL_error(state, "Cannot allocate %s%s%s",
            id->getFullName().c_str(),
            err_context.empty() ? "" : ": ",
            err_context.c_str()
        );

    if (lua_isuserdata(state, 1))
    {
        lua_getmetatable(state, 1);
        push_object_ref(state, ptr);

        id->copy(ptr, get_object_ref(state, 1));
    }
    else
        push_object_internal(state, id, ptr);

    return 1;
}