nodetimer.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#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) {
                auto 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) {
                auto 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 behavior if there already is a timer
        void insert(const NodeTimer &timer) {
                v3s16 p = timer.position;
                double trigger_time = m_time + (double)(timer.timeout - timer.elapsed);
                auto it = m_timers.emplace(trigger_time, timer);
                m_iterators.emplace(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;
};