ui_timer.cpp

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/*
Copyright (C) 2002-2020 UFO: Alien Invasion.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "../cl_shared.h"
#include "ui_nodes.h"
#include "ui_timer.h"

#define UI_TIMER_SLOT_NUMBER 10

static uiTimer_t ui_timerSlots[UI_TIMER_SLOT_NUMBER];

static uiTimer_t* ui_firstTimer;

static inline void UI_RemoveTimerFromActiveList (uiTimer_t* timer)
{
    assert(timer >= ui_timerSlots && timer < ui_timerSlots + UI_TIMER_SLOT_NUMBER);
    if (timer->prev) {
        timer->prev->next = timer->next;
    } else {
        ui_firstTimer = timer->next;
    }
    if (timer->next) {
        timer->next->prev = timer->prev;
    }
}

static void UI_InsertTimerInActiveList (uiTimer_t* first, uiTimer_t* newTimer)
{
    uiTimer_t* current = first;
    uiTimer_t* prev = nullptr;

    /* find insert position */
    if (current != nullptr) {
        prev = current->prev;
    }
    while (current) {
        if (newTimer->nextTime < current->nextTime)
            break;
        prev = current;
        current = current->next;
    }

    /* insert between previous and current */
    newTimer->prev = prev;
    newTimer->next = current;
    if (current != nullptr) {
        current->prev = newTimer;
    }
    if (prev != nullptr) {
        prev->next = newTimer;
    } else {
        ui_firstTimer = newTimer;
    }
}

void UI_HandleTimers (void)
{
    /* is first element is out of date? */
    while (ui_firstTimer && ui_firstTimer->nextTime <= CL_Milliseconds()) {
        uiTimer_t* timer = ui_firstTimer;

        /* throw event */
        timer->calledTime++;
        timer->callback(timer->owner, timer);

        /* update the sorted list */
        if (timer->isRunning) {
            UI_RemoveTimerFromActiveList(timer);
            timer->nextTime += timer->delay;
            UI_InsertTimerInActiveList(timer->next, timer);
        }
    }
}

uiTimer_t* UI_AllocTimer (uiNode_t* node, int firstDelay, timerCallback_t callback)
{
    uiTimer_t* timer = nullptr;

    /* search empty slot */
    for (int i = 0; i < UI_TIMER_SLOT_NUMBER; i++) {
        if (ui_timerSlots[i].callback != nullptr)
            continue;
        timer = ui_timerSlots + i;
        break;
    }
    if (timer == nullptr)
        Com_Error(ERR_FATAL, "UI_AllocTimer: No more timer slot");

    timer->owner = node;
    timer->delay = firstDelay;
    timer->callback = callback;
    timer->calledTime = 0;
    timer->prev = nullptr;
    timer->next = nullptr;
    timer->isRunning = false;
    return timer;
}

void UI_TimerStart (uiTimer_t* timer)
{
    if (timer->isRunning)
        return;
    assert(ui_firstTimer != timer && timer->prev == nullptr && timer->next == nullptr);
    timer->nextTime = CL_Milliseconds() + timer->delay;
    timer->isRunning = true;
    UI_InsertTimerInActiveList(ui_firstTimer, timer);
}

void UI_TimerStop (uiTimer_t* timer)
{
    if (!timer->isRunning)
        return;
    UI_RemoveTimerFromActiveList(timer);
    timer->prev = nullptr;
    timer->next = nullptr;
    timer->isRunning = false;
}

void UI_TimerRelease (uiTimer_t* timer)
{
    UI_RemoveTimerFromActiveList(timer);
    timer->prev = nullptr;
    timer->next = nullptr;
    timer->owner = nullptr;
    timer->callback = nullptr;
}

void UI_ResetTimers (void)
{
    OBJZERO(ui_timerSlots);
    ui_firstTimer = nullptr;
}

#ifdef COMPILE_UNITTESTS

const uiTimer_t* UI_PrivateGetFirstTimer (void)
{
    return ui_firstTimer;
}

void UI_PrivateInsertTimerInActiveList (uiTimer_t* first, uiTimer_t* newTimer)
{
    UI_InsertTimerInActiveList(first, newTimer);
}

#endif