void engine::parse_goal_from_config( readonly_context &context, const config &cfg, std::back_insert_iterator<std::vector< goal_ptr > > b )
{
	engine_ptr eng = context.get_engine_by_cfg(cfg);
	if (eng){
		//do not override that method in subclasses which cannot create goals
		eng->do_parse_goal_from_config(cfg, b);
	}
}

 remove_wrong_targets(const readonly_context &context)
     :avoid_(context.get_avoid()), map_(resources::gameboard->map())
 {
 }

void attack_analysis::analyze(const gamemap& map, unit_map& units,
                              const readonly_context& ai_obj,
                              const move_map& dstsrc, const move_map& srcdst,
                              const move_map& enemy_dstsrc, double aggression)
{
	const unit_map::const_iterator defend_it = units.find(target);
	assert(defend_it != units.end());

	// See if the target is a threat to our leader or an ally's leader.
	map_location adj[6];
	get_adjacent_tiles(target,adj);
	size_t tile;
	for(tile = 0; tile != 6; ++tile) {
		const unit_map::const_iterator leader = units.find(adj[tile]);
		if(leader != units.end() && leader->can_recruit() && !ai_obj.current_team().is_enemy(leader->side())) {
			break;
		}
	}

	leader_threat = (tile != 6);
	uses_leader = false;

	target_value = defend_it->cost();
	target_value += (double(defend_it->experience())/
	                 double(defend_it->max_experience()))*target_value;
	target_starting_damage = defend_it->max_hitpoints() -
	                         defend_it->hitpoints();

	// Calculate the 'alternative_terrain_quality' -- the best possible defensive values
	// the attacking units could hope to achieve if they didn't attack and moved somewhere.
	// This is used for comparative purposes, to see just how vulnerable the AI is
	// making itself.
	alternative_terrain_quality = 0.0;
	double cost_sum = 0.0;
	for(size_t i = 0; i != movements.size(); ++i) {
		const unit_map::const_iterator att = units.find(movements[i].first);
		const double cost = att->cost();
		cost_sum += cost;
		alternative_terrain_quality += cost*ai_obj.best_defensive_position(movements[i].first,dstsrc,srcdst,enemy_dstsrc).chance_to_hit;
	}
	alternative_terrain_quality /= cost_sum*100;

	avg_damage_inflicted = 0.0;
	avg_damage_taken = 0.0;
	resources_used = 0.0;
	terrain_quality = 0.0;
	avg_losses = 0.0;
	chance_to_kill = 0.0;

	double def_avg_experience = 0.0;
	double first_chance_kill = 0.0;

	double prob_dead_already = 0.0;
	assert(!movements.empty());
	std::vector<std::pair<map_location,map_location> >::const_iterator m;

	battle_context *prev_bc = NULL;
	const combatant *prev_def = NULL;

	for (m = movements.begin(); m != movements.end(); ++m) {
		// We fix up units map to reflect what this would look like.
		unit_ptr up = units.extract(m->first);
		up->set_location(m->second);
		units.insert(up);
		double m_aggression = aggression;

		if (up->can_recruit()) {
			uses_leader = true;
			// FIXME: suokko's r29531 omitted this line
			leader_threat = false;
			m_aggression = ai_obj.get_leader_aggression();
		}

		bool from_cache = false;
		battle_context *bc;

		// This cache is only about 99% correct, but speeds up evaluation by about 1000 times.
		// We recalculate when we actually attack.
		const readonly_context::unit_stats_cache_t::key_type cache_key = std::make_pair(target, &up->type());
		const readonly_context::unit_stats_cache_t::iterator usc = ai_obj.unit_stats_cache().find(cache_key);
		// Just check this attack is valid for this attacking unit (may be modified)
		if (usc != ai_obj.unit_stats_cache().end() &&
				usc->second.first.attack_num <
				static_cast<int>(up->attacks().size())) {

			from_cache = true;
			bc = new battle_context(usc->second.first, usc->second.second);
		} else {
			bc = new battle_context(units, m->second, target, -1, -1, m_aggression, prev_def);
		}
		const combatant &att = bc->get_attacker_combatant(prev_def);
		const combatant &def = bc->get_defender_combatant(prev_def);

		delete prev_bc;
		prev_bc = bc;
		prev_def = &bc->get_defender_combatant(prev_def);

		if ( !from_cache ) {
			ai_obj.unit_stats_cache().insert(
				std::make_pair(cache_key, std::make_pair(bc->get_attacker_stats(),
//.........这里部分代码省略.........

double attack_analysis::rating(double aggression, const readonly_context& ai_obj) const
{
	if(leader_threat) {
		aggression = 1.0;
	}

	if(uses_leader) {
		aggression = ai_obj.get_leader_aggression();
	}

	double value = chance_to_kill*target_value - avg_losses*(1.0-aggression);

	if(terrain_quality > alternative_terrain_quality) {
		// This situation looks like it might be a bad move:
		// we are moving our attackers out of their optimal terrain
		// into sub-optimal terrain.
		// Calculate the 'exposure' of our units to risk.

#ifdef SUOKKO
		//FIXME: this code was in sukko's r29531  Correct?
		const double exposure_mod = uses_leader ? ai_obj.current_team().caution()* 8.0 : ai_obj.current_team().caution() * 4.0;
		const double exposure = exposure_mod*resources_used*((terrain_quality - alternative_terrain_quality)/10)*vulnerability/std::max<double>(0.01,support);
#else
		const double exposure_mod = uses_leader ? 2.0 : ai_obj.get_caution();
		const double exposure = exposure_mod*resources_used*(terrain_quality - alternative_terrain_quality)*vulnerability/std::max<double>(0.01,support);
#endif
		LOG_AI << "attack option has base value " << value << " with exposure " << exposure << ": "
			<< vulnerability << "/" << support << " = " << (vulnerability/std::max<double>(support,0.1)) << "\n";
		value -= exposure*(1.0-aggression);
	}

	// Prefer to attack already damaged targets.
	value += ((target_starting_damage/3 + avg_damage_inflicted) - (1.0-aggression)*avg_damage_taken)/10.0;

       // If the unit is surrounded and there is no support,
	   // or if the unit is surrounded and the average damage is 0,
	   // the unit skips its sanity check and tries to break free as good as possible.
       if(!is_surrounded || (support != 0 && avg_damage_taken != 0))
       {
               // Sanity check: if we're putting ourselves at major risk,
			   // and have no chance to kill, and we're not aiding our allies
			   // who are also attacking, then don't do it.
               if(vulnerability > 50.0 && vulnerability > support*2.0
			   && chance_to_kill < 0.02 && aggression < 0.75
			   && !attack_close(target)) {
                       return -1.0;
               }
        }

	if(!leader_threat && vulnerability*terrain_quality > 0.0  && !is_surrounded) {
		value *= support/(vulnerability*terrain_quality);
	}

	value /= ((resources_used/2) + (resources_used/2)*terrain_quality);

	if(leader_threat) {
		value *= 5.0;
	}

	LOG_AI << "attack on " << target << ": attackers: " << movements.size()
		<< " value: " << value << " chance to kill: " << chance_to_kill
		<< " damage inflicted: " << avg_damage_inflicted
		<< " damage taken: " << avg_damage_taken
		<< " vulnerability: " << vulnerability
		<< " support: " << support
		<< " quality: " << terrain_quality
		<< " alternative quality: " << alternative_terrain_quality << "\n";

	return value;
}

	remove_wrong_targets(const readonly_context &context)
		:avoid_(context.get_avoid()), map_(*resources::game_map)
	{
	}