}
static bool _increase_ench_duration(monsters *mon,
                                    mon_enchant ench,
                                    const int increase)
{
    // Durations are saved as 16-bit signed ints, so clamp at the largest such.
    const int MARSHALL_MAX = (1 << 15) - 1;
    const int newdur = std::min(ench.duration + increase, MARSHALL_MAX);
    if (ench.duration >= newdur)
        return false;
    ench.duration = newdur;
    mon->update_ench(ench);
    return true;

    const int increase = 300 + random2(300);
    const int threshold = (increase + random2(increase)) * 2;
    // Extend the time an abjurable monster has before disappearing.
    abj.duration += increase;
    // If the extended stay is long enough, make it permanent.  Note
    // that we have to delete the enchantment without removing the
    // enchantment effect, in order to keep the monster from
    // disappearing.
    if (abj.duration >= threshold)
    {
        mon->del_ench(ENCH_ABJ, true, false);
        return 2;
    }
    else
        mon->update_ench(abj);

    return 1;

    // [ds] Disabling permanence for balance reasons, but extending duration
    // increase. These numbers are tenths of a player turn. Holy monsters
    // get a much bigger boost than random beasties.
    const int base_increase = mon->holiness() == MH_HOLY? 1100 : 500;
    const int increase = base_increase + random2(base_increase);
    return _increase_ench_duration(mon, abj, increase);

    mon->attitude = ATT_FRIENDLY;
    // The monster is not really *created* friendly, but should it
    // become hostile later on, it won't count as a good kill.
    mon->flags |= MF_CREATED_FRIENDLY;
    mons_make_god_gift(mon, GOD_SHINING_ONE);

    // If the monster is charmed, make it permanently friendly.  Note
    // that we have to delete the enchantment without removing the
    // enchantment effect, in order to keep the monster from turning
    // hostile.
    mon->del_ench(ENCH_CHARM, true, false);
    return (true);

    // [ds] Just increase charm duration, no permanent friendliness.
    const int base_increase = 700;
    return _increase_ench_duration(mon, mon->get_ench(ENCH_CHARM),
                                   base_increase + random2(base_increase));

                || one_chance_in(3))

                || !one_chance_in(3))

    {        

    {