nodetimer.h

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/*
Minetest
Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.
 
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
 
#pragma once
 
#include "irr_v3d.h"
#include <iostream>
#include <map>
#include <vector>
 
/*
    NodeTimer provides per-node timed callback functionality.
    Can be used for:
    - Furnaces, to keep the fire burnin'
    - "activated" nodes that snap back to their original state
      after a fixed amount of time (mesecons buttons, for example)
*/
 
class NodeTimer
{
public:
    NodeTimer() = default;
    NodeTimer(const v3s16 &position_):
        position(position_) {}
    NodeTimer(f32 timeout_, f32 elapsed_, v3s16 position_):
        timeout(timeout_), elapsed(elapsed_), position(position_) {}
    ~NodeTimer() = default;
 
    void serialize(std::ostream &os) const;
    void deSerialize(std::istream &is);
 
    f32 timeout = 0.0f;
    f32 elapsed = 0.0f;
    v3s16 position;
};
 
/*
    List of timers of all the nodes of a block
*/
 
class NodeTimerList
{
public:
    NodeTimerList() = default;
    ~NodeTimerList() = default;
 
    void serialize(std::ostream &os, u8 map_format_version) const;
    void deSerialize(std::istream &is, u8 map_format_version);
 
    // Get timer
    NodeTimer get(const v3s16 &p) {
        std::map<v3s16, std::multimap<double, NodeTimer>::iterator>::iterator n =
            m_iterators.find(p);
        if (n == m_iterators.end())
            return NodeTimer();
        NodeTimer t = n->second->second;
        t.elapsed = t.timeout - (n->second->first - m_time);
        return t;
    }
    // Deletes timer
    void remove(v3s16 p) {
        std::map<v3s16, std::multimap<double, NodeTimer>::iterator>::iterator n =
            m_iterators.find(p);
        if(n != m_iterators.end()) {
            double removed_time = n->second->first;
            m_timers.erase(n->second);
            m_iterators.erase(n);
            // Yes, this is float equality, but it is not a problem
            // since we only test equality of floats as an ordered type
            // and thus we never lose precision
            if (removed_time == m_next_trigger_time) {
                if (m_timers.empty())
                    m_next_trigger_time = -1.;
                else
                    m_next_trigger_time = m_timers.begin()->first;
            }
        }
    }
    // Undefined behaviour if there already is a timer
    void insert(NodeTimer timer) {
        v3s16 p = timer.position;
        double trigger_time = m_time + (double)(timer.timeout - timer.elapsed);
        std::multimap<double, NodeTimer>::iterator it =
            m_timers.insert(std::pair<double, NodeTimer>(
                trigger_time, timer
            ));
        m_iterators.insert(
            std::pair<v3s16, std::multimap<double, NodeTimer>::iterator>(p, it));
        if (m_next_trigger_time == -1. || trigger_time < m_next_trigger_time)
            m_next_trigger_time = trigger_time;
    }
    // Deletes old timer and sets a new one
    inline void set(const NodeTimer &timer) {
        remove(timer.position);
        insert(timer);
    }
    // Deletes all timers
    void clear() {
        m_timers.clear();
        m_iterators.clear();
        m_next_trigger_time = -1.;
    }
 
    // Move forward in time, returns elapsed timers
    std::vector<NodeTimer> step(float dtime);
 
private:
    std::multimap<double, NodeTimer> m_timers;
    std::map<v3s16, std::multimap<double, NodeTimer>::iterator> m_iterators;
    double m_next_trigger_time = -1.0;
    double m_time = 0.0;
};