Function meta_enum_attr_index

library/LuaWrapper.cpp:1049–1080

* Metamethod: __index for enum.attrs */

 * Metamethod: __index for enum.attrs
 */
static int meta_enum_attr_index(lua_State *state)
{
    if (!lua_isnumber(state, 2))
        lua_rawget(state, UPVAL_FIELDTABLE);
    if (!lua_isnumber(state, 2))
        luaL_error(state, "Invalid index in enum.attrs[]");

    auto id = (enum_identity*)lua_touserdata(state, lua_upvalueindex(2));
    auto *complex = id->getComplex();

    int64_t idx = lua_tonumber(state, 2);
    if (complex)
    {
        auto it = complex->value_index_map.find(idx);
        if (it != complex->value_index_map.end())
            idx = int64_t(it->second);
        else
            idx = id->getLastItem() + 1;
    }
    else
    {
        if (idx < id->getFirstItem() || idx > id->getLastItem())
            idx = id->getLastItem()+1;
        idx -= id->getFirstItem();
    }

    uint8_t *ptr = (uint8_t*)id->getAttrs();
    auto atype = id->getAttrType();

    push_object_internal(state, atype, ptr + unsigned(atype->byte_size()*idx));
    return 1;
}

/**
 * Metamethod: df.isvalid(obj[,allow_null])