1 files changed, 734 insertions, 0 deletions

diff --git a/contrib/SDL-3.2.8/src/timer/SDL_timer.c b/contrib/SDL-3.2.8/src/timer/SDL_timer.c
new file mode 100644
index 0000000..2fa6553
--- /dev/null
+++ b/contrib/SDL-3.2.8/src/timer/SDL_timer.c
@@ -0,0 +1,734 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#include "SDL_timer_c.h"
+#include "../thread/SDL_systhread.h"
+
+// #define DEBUG_TIMERS
+
+#if !defined(SDL_PLATFORM_EMSCRIPTEN) || !defined(SDL_THREADS_DISABLED)
+
+typedef struct SDL_Timer
+{
+    SDL_TimerID timerID;
+    SDL_TimerCallback callback_ms;
+    SDL_NSTimerCallback callback_ns;
+    void *userdata;
+    Uint64 interval;
+    Uint64 scheduled;
+    SDL_AtomicInt canceled;
+    struct SDL_Timer *next;
+} SDL_Timer;
+
+typedef struct SDL_TimerMap
+{
+    SDL_TimerID timerID;
+    SDL_Timer *timer;
+    struct SDL_TimerMap *next;
+} SDL_TimerMap;
+
+// The timers are kept in a sorted list
+typedef struct
+{
+    // Data used by the main thread
+    SDL_InitState init;
+    SDL_Thread *thread;
+    SDL_TimerMap *timermap;
+    SDL_Mutex *timermap_lock;
+
+    // Padding to separate cache lines between threads
+    char cache_pad[SDL_CACHELINE_SIZE];
+
+    // Data used to communicate with the timer thread
+    SDL_SpinLock lock;
+    SDL_Semaphore *sem;
+    SDL_Timer *pending;
+    SDL_Timer *freelist;
+    SDL_AtomicInt active;
+
+    // List of timers - this is only touched by the timer thread
+    SDL_Timer *timers;
+} SDL_TimerData;
+
+static SDL_TimerData SDL_timer_data;
+
+/* The idea here is that any thread might add a timer, but a single
+ * thread manages the active timer queue, sorted by scheduling time.
+ *
+ * Timers are removed by simply setting a canceled flag
+ */
+
+static void SDL_AddTimerInternal(SDL_TimerData *data, SDL_Timer *timer)
+{
+    SDL_Timer *prev, *curr;
+
+    prev = NULL;
+    for (curr = data->timers; curr; prev = curr, curr = curr->next) {
+        if (curr->scheduled > timer->scheduled) {
+            break;
+        }
+    }
+
+    // Insert the timer here!
+    if (prev) {
+        prev->next = timer;
+    } else {
+        data->timers = timer;
+    }
+    timer->next = curr;
+}
+
+static int SDLCALL SDL_TimerThread(void *_data)
+{
+    SDL_TimerData *data = (SDL_TimerData *)_data;
+    SDL_Timer *pending;
+    SDL_Timer *current;
+    SDL_Timer *freelist_head = NULL;
+    SDL_Timer *freelist_tail = NULL;
+    Uint64 tick, now, interval, delay;
+
+    /* Threaded timer loop:
+     *  1. Queue timers added by other threads
+     *  2. Handle any timers that should dispatch this cycle
+     *  3. Wait until next dispatch time or new timer arrives
+     */
+    for (;;) {
+        // Pending and freelist maintenance
+        SDL_LockSpinlock(&data->lock);
+        {
+            // Get any timers ready to be queued
+            pending = data->pending;
+            data->pending = NULL;
+
+            // Make any unused timer structures available
+            if (freelist_head) {
+                freelist_tail->next = data->freelist;
+                data->freelist = freelist_head;
+            }
+        }
+        SDL_UnlockSpinlock(&data->lock);
+
+        // Sort the pending timers into our list
+        while (pending) {
+            current = pending;
+            pending = pending->next;
+            SDL_AddTimerInternal(data, current);
+        }
+        freelist_head = NULL;
+        freelist_tail = NULL;
+
+        // Check to see if we're still running, after maintenance
+        if (!SDL_GetAtomicInt(&data->active)) {
+            break;
+        }
+
+        // Initial delay if there are no timers
+        delay = (Uint64)-1;
+
+        tick = SDL_GetTicksNS();
+
+        // Process all the pending timers for this tick
+        while (data->timers) {
+            current = data->timers;
+
+            if (tick < current->scheduled) {
+                // Scheduled for the future, wait a bit
+                delay = (current->scheduled - tick);
+                break;
+            }
+
+            // We're going to do something with this timer
+            data->timers = current->next;
+
+            if (SDL_GetAtomicInt(&current->canceled)) {
+                interval = 0;
+            } else {
+                if (current->callback_ms) {
+                    interval = SDL_MS_TO_NS(current->callback_ms(current->userdata, current->timerID, (Uint32)SDL_NS_TO_MS(current->interval)));
+                } else {
+                    interval = current->callback_ns(current->userdata, current->timerID, current->interval);
+                }
+            }
+
+            if (interval > 0) {
+                // Reschedule this timer
+                current->interval = interval;
+                current->scheduled = tick + interval;
+                SDL_AddTimerInternal(data, current);
+            } else {
+                if (!freelist_head) {
+                    freelist_head = current;
+                }
+                if (freelist_tail) {
+                    freelist_tail->next = current;
+                }
+                freelist_tail = current;
+
+                SDL_SetAtomicInt(&current->canceled, 1);
+            }
+        }
+
+        // Adjust the delay based on processing time
+        now = SDL_GetTicksNS();
+        interval = (now - tick);
+        if (interval > delay) {
+            delay = 0;
+        } else {
+            delay -= interval;
+        }
+
+        /* Note that each time a timer is added, this will return
+           immediately, but we process the timers added all at once.
+           That's okay, it just means we run through the loop a few
+           extra times.
+         */
+        SDL_WaitSemaphoreTimeoutNS(data->sem, delay);
+    }
+    return 0;
+}
+
+bool SDL_InitTimers(void)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+
+    if (!SDL_ShouldInit(&data->init)) {
+        return true;
+    }
+
+    data->timermap_lock = SDL_CreateMutex();
+    if (!data->timermap_lock) {
+        goto error;
+    }
+
+    data->sem = SDL_CreateSemaphore(0);
+    if (!data->sem) {
+        goto error;
+    }
+
+    SDL_SetAtomicInt(&data->active, true);
+
+    // Timer threads use a callback into the app, so we can't set a limited stack size here.
+    data->thread = SDL_CreateThread(SDL_TimerThread, "SDLTimer", data);
+    if (!data->thread) {
+        goto error;
+    }
+
+    SDL_SetInitialized(&data->init, true);
+    return true;
+
+error:
+    SDL_SetInitialized(&data->init, true);
+    SDL_QuitTimers();
+    return false;
+}
+
+void SDL_QuitTimers(void)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_Timer *timer;
+    SDL_TimerMap *entry;
+
+    if (!SDL_ShouldQuit(&data->init)) {
+        return;
+    }
+
+    SDL_SetAtomicInt(&data->active, false);
+
+    // Shutdown the timer thread
+    if (data->thread) {
+        SDL_SignalSemaphore(data->sem);
+        SDL_WaitThread(data->thread, NULL);
+        data->thread = NULL;
+    }
+
+    if (data->sem) {
+        SDL_DestroySemaphore(data->sem);
+        data->sem = NULL;
+    }
+
+    // Clean up the timer entries
+    while (data->timers) {
+        timer = data->timers;
+        data->timers = timer->next;
+        SDL_free(timer);
+    }
+    while (data->freelist) {
+        timer = data->freelist;
+        data->freelist = timer->next;
+        SDL_free(timer);
+    }
+    while (data->timermap) {
+        entry = data->timermap;
+        data->timermap = entry->next;
+        SDL_free(entry);
+    }
+
+    if (data->timermap_lock) {
+        SDL_DestroyMutex(data->timermap_lock);
+        data->timermap_lock = NULL;
+    }
+
+    SDL_SetInitialized(&data->init, false);
+}
+
+static bool SDL_CheckInitTimers(void)
+{
+    return SDL_InitTimers();
+}
+
+static SDL_TimerID SDL_CreateTimer(Uint64 interval, SDL_TimerCallback callback_ms, SDL_NSTimerCallback callback_ns, void *userdata)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_Timer *timer;
+    SDL_TimerMap *entry;
+
+    if (!callback_ms && !callback_ns) {
+        SDL_InvalidParamError("callback");
+        return 0;
+    }
+
+    if (!SDL_CheckInitTimers()) {
+        return 0;
+    }
+
+    SDL_LockSpinlock(&data->lock);
+    timer = data->freelist;
+    if (timer) {
+        data->freelist = timer->next;
+    }
+    SDL_UnlockSpinlock(&data->lock);
+
+    if (timer) {
+        SDL_RemoveTimer(timer->timerID);
+    } else {
+        timer = (SDL_Timer *)SDL_malloc(sizeof(*timer));
+        if (!timer) {
+            return 0;
+        }
+    }
+    timer->timerID = SDL_GetNextObjectID();
+    timer->callback_ms = callback_ms;
+    timer->callback_ns = callback_ns;
+    timer->userdata = userdata;
+    timer->interval = interval;
+    timer->scheduled = SDL_GetTicksNS() + timer->interval;
+    SDL_SetAtomicInt(&timer->canceled, 0);
+
+    entry = (SDL_TimerMap *)SDL_malloc(sizeof(*entry));
+    if (!entry) {
+        SDL_free(timer);
+        return 0;
+    }
+    entry->timer = timer;
+    entry->timerID = timer->timerID;
+
+    SDL_LockMutex(data->timermap_lock);
+    entry->next = data->timermap;
+    data->timermap = entry;
+    SDL_UnlockMutex(data->timermap_lock);
+
+    // Add the timer to the pending list for the timer thread
+    SDL_LockSpinlock(&data->lock);
+    timer->next = data->pending;
+    data->pending = timer;
+    SDL_UnlockSpinlock(&data->lock);
+
+    // Wake up the timer thread if necessary
+    SDL_SignalSemaphore(data->sem);
+
+    return entry->timerID;
+}
+
+SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_TimerCallback callback, void *userdata)
+{
+    return SDL_CreateTimer(SDL_MS_TO_NS(interval), callback, NULL, userdata);
+}
+
+SDL_TimerID SDL_AddTimerNS(Uint64 interval, SDL_NSTimerCallback callback, void *userdata)
+{
+    return SDL_CreateTimer(interval, NULL, callback, userdata);
+}
+
+bool SDL_RemoveTimer(SDL_TimerID id)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_TimerMap *prev, *entry;
+    bool canceled = false;
+
+    if (!id) {
+        return SDL_InvalidParamError("id");
+    }
+
+    // Find the timer
+    SDL_LockMutex(data->timermap_lock);
+    prev = NULL;
+    for (entry = data->timermap; entry; prev = entry, entry = entry->next) {
+        if (entry->timerID == id) {
+            if (prev) {
+                prev->next = entry->next;
+            } else {
+                data->timermap = entry->next;
+            }
+            break;
+        }
+    }
+    SDL_UnlockMutex(data->timermap_lock);
+
+    if (entry) {
+        if (!SDL_GetAtomicInt(&entry->timer->canceled)) {
+            SDL_SetAtomicInt(&entry->timer->canceled, 1);
+            canceled = true;
+        }
+        SDL_free(entry);
+    }
+    if (canceled) {
+        return true;
+    } else {
+        return SDL_SetError("Timer not found");
+    }
+}
+
+#else
+
+#include <emscripten/emscripten.h>
+#include <emscripten/eventloop.h>
+
+typedef struct SDL_TimerMap
+{
+    SDL_TimerID timerID;
+    int timeoutID;
+    Uint64 interval;
+    SDL_TimerCallback callback_ms;
+    SDL_NSTimerCallback callback_ns;
+    void *userdata;
+    struct SDL_TimerMap *next;
+} SDL_TimerMap;
+
+typedef struct
+{
+    SDL_TimerMap *timermap;
+} SDL_TimerData;
+
+static SDL_TimerData SDL_timer_data;
+
+static void SDL_Emscripten_TimerHelper(void *userdata)
+{
+    SDL_TimerMap *entry = (SDL_TimerMap *)userdata;
+    if (entry->callback_ms) {
+        entry->interval = SDL_MS_TO_NS(entry->callback_ms(entry->userdata, entry->timerID, (Uint32)SDL_NS_TO_MS(entry->interval)));
+    } else {
+        entry->interval = entry->callback_ns(entry->userdata, entry->timerID, entry->interval);
+    }
+    if (entry->interval > 0) {
+        entry->timeoutID = emscripten_set_timeout(&SDL_Emscripten_TimerHelper,
+                                                  SDL_NS_TO_MS(entry->interval),
+                                                  entry);
+    }
+}
+
+bool SDL_InitTimers(void)
+{
+    return true;
+}
+
+void SDL_QuitTimers(void)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_TimerMap *entry;
+
+    while (data->timermap) {
+        entry = data->timermap;
+        data->timermap = entry->next;
+        SDL_free(entry);
+    }
+}
+
+static SDL_TimerID SDL_CreateTimer(Uint64 interval, SDL_TimerCallback callback_ms, SDL_NSTimerCallback callback_ns, void *userdata)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_TimerMap *entry;
+
+    if (!callback_ms && !callback_ns) {
+        SDL_InvalidParamError("callback");
+        return 0;
+    }
+
+    entry = (SDL_TimerMap *)SDL_malloc(sizeof(*entry));
+    if (!entry) {
+        return 0;
+    }
+    entry->timerID = SDL_GetNextObjectID();
+    entry->callback_ms = callback_ms;
+    entry->callback_ns = callback_ns;
+    entry->userdata = userdata;
+    entry->interval = interval;
+
+    entry->timeoutID = emscripten_set_timeout(&SDL_Emscripten_TimerHelper,
+                                              SDL_NS_TO_MS(entry->interval),
+                                              entry);
+
+    entry->next = data->timermap;
+    data->timermap = entry;
+
+    return entry->timerID;
+}
+
+SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_TimerCallback callback, void *userdata)
+{
+    return SDL_CreateTimer(SDL_MS_TO_NS(interval), callback, NULL, userdata);
+}
+
+SDL_TimerID SDL_AddTimerNS(Uint64 interval, SDL_NSTimerCallback callback, void *userdata)
+{
+    return SDL_CreateTimer(interval, NULL, callback, userdata);
+}
+
+bool SDL_RemoveTimer(SDL_TimerID id)
+{
+    SDL_TimerData *data = &SDL_timer_data;
+    SDL_TimerMap *prev, *entry;
+
+    if (!id) {
+        return SDL_InvalidParamError("id");
+    }
+
+    // Find the timer
+    prev = NULL;
+    for (entry = data->timermap; entry; prev = entry, entry = entry->next) {
+        if (entry->timerID == id) {
+            if (prev) {
+                prev->next = entry->next;
+            } else {
+                data->timermap = entry->next;
+            }
+            break;
+        }
+    }
+
+    if (entry) {
+        emscripten_clear_timeout(entry->timeoutID);
+        SDL_free(entry);
+        return true;
+    } else {
+        return SDL_SetError("Timer not found");
+    }
+}
+
+#endif // !SDL_PLATFORM_EMSCRIPTEN || !SDL_THREADS_DISABLED
+
+static Uint64 tick_start;
+static Uint32 tick_numerator_ns;
+static Uint32 tick_denominator_ns;
+static Uint32 tick_numerator_ms;
+static Uint32 tick_denominator_ms;
+
+#if defined(SDL_TIMER_WINDOWS) && !defined(SDL_PLATFORM_XBOXONE) && !defined(SDL_PLATFORM_XBOXSERIES)
+#include <mmsystem.h>
+#define HAVE_TIME_BEGIN_PERIOD
+#endif
+
+static void SDL_SetSystemTimerResolutionMS(int period)
+{
+#ifdef HAVE_TIME_BEGIN_PERIOD
+    static int timer_period = 0;
+
+    if (period != timer_period) {
+        if (timer_period) {
+            timeEndPeriod((UINT)timer_period);
+        }
+
+        timer_period = period;
+
+        if (timer_period) {
+            timeBeginPeriod((UINT)timer_period);
+        }
+    }
+#endif // HAVE_TIME_BEGIN_PERIOD
+}
+
+static void SDLCALL SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
+{
+    int period;
+
+    // Unless the hint says otherwise, let's have good sleep precision
+    if (hint && *hint) {
+        period = SDL_atoi(hint);
+    } else {
+        period = 1;
+    }
+    if (period || oldValue != hint) {
+        SDL_SetSystemTimerResolutionMS(period);
+    }
+}
+
+void SDL_InitTicks(void)
+{
+    Uint64 tick_freq;
+    Uint32 gcd;
+
+    if (tick_start) {
+        return;
+    }
+
+    /* If we didn't set a precision, set it high. This affects lots of things
+       on Windows besides the SDL timers, like audio callbacks, etc. */
+    SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
+                        SDL_TimerResolutionChanged, NULL);
+
+    tick_freq = SDL_GetPerformanceFrequency();
+    SDL_assert(tick_freq > 0 && tick_freq <= (Uint64)SDL_MAX_UINT32);
+
+    gcd = SDL_CalculateGCD(SDL_NS_PER_SECOND, (Uint32)tick_freq);
+    tick_numerator_ns = (SDL_NS_PER_SECOND / gcd);
+    tick_denominator_ns = (Uint32)(tick_freq / gcd);
+
+    gcd = SDL_CalculateGCD(SDL_MS_PER_SECOND, (Uint32)tick_freq);
+    tick_numerator_ms = (SDL_MS_PER_SECOND / gcd);
+    tick_denominator_ms = (Uint32)(tick_freq / gcd);
+
+    tick_start = SDL_GetPerformanceCounter();
+    if (!tick_start) {
+        --tick_start;
+    }
+}
+
+void SDL_QuitTicks(void)
+{
+    SDL_RemoveHintCallback(SDL_HINT_TIMER_RESOLUTION,
+                        SDL_TimerResolutionChanged, NULL);
+
+    SDL_SetSystemTimerResolutionMS(0); // always release our timer resolution request.
+
+    tick_start = 0;
+}
+
+Uint64 SDL_GetTicksNS(void)
+{
+    Uint64 starting_value, value;
+
+    if (!tick_start) {
+        SDL_InitTicks();
+    }
+
+    starting_value = (SDL_GetPerformanceCounter() - tick_start);
+    value = (starting_value * tick_numerator_ns);
+    SDL_assert(value >= starting_value);
+    value /= tick_denominator_ns;
+    return value;
+}
+
+Uint64 SDL_GetTicks(void)
+{
+    Uint64 starting_value, value;
+
+    if (!tick_start) {
+        SDL_InitTicks();
+    }
+
+    starting_value = (SDL_GetPerformanceCounter() - tick_start);
+    value = (starting_value * tick_numerator_ms);
+    SDL_assert(value >= starting_value);
+    value /= tick_denominator_ms;
+    return value;
+}
+
+void SDL_Delay(Uint32 ms)
+{
+    SDL_SYS_DelayNS(SDL_MS_TO_NS(ms));
+}
+
+void SDL_DelayNS(Uint64 ns)
+{
+    SDL_SYS_DelayNS(ns);
+}
+
+void SDL_DelayPrecise(Uint64 ns)
+{
+    Uint64 current_value = SDL_GetTicksNS();
+    const Uint64 target_value = current_value + ns;
+
+    // Sleep for a short number of cycles when real sleeps are desired.
+    // We'll use 1 ms, it's the minimum guaranteed to produce real sleeps across
+    // all platforms.
+    const Uint64 SHORT_SLEEP_NS = 1 * SDL_NS_PER_MS;
+
+    // Try to sleep short of target_value. If for some crazy reason
+    // a particular platform sleeps for less than 1 ms when 1 ms was requested,
+    // that's fine, the code below can cope with that, but in practice no
+    // platforms behave that way.
+    Uint64 max_sleep_ns = SHORT_SLEEP_NS;
+    while (current_value + max_sleep_ns < target_value) {
+        // Sleep for a short time
+        SDL_SYS_DelayNS(SHORT_SLEEP_NS);
+
+        const Uint64 now = SDL_GetTicksNS();
+        const Uint64 next_sleep_ns = (now - current_value);
+        if (next_sleep_ns > max_sleep_ns) {
+            max_sleep_ns = next_sleep_ns;
+        }
+        current_value = now;
+    }
+
+    // Do a shorter sleep of the remaining time here, less the max overshoot in
+    // the first loop. Due to maintaining max_sleep_ns as
+    // greater-than-or-equal-to-1 ms, we can always subtract off 1 ms to get
+    // the duration overshot beyond a 1 ms sleep request; if the system never
+    // overshot, great, it's zero duration. By choosing the max overshoot
+    // amount, we're likely to not overshoot here. If the sleep here ends up
+    // functioning like SDL_DelayNS(0) internally, that's fine, we just don't
+    // get to do a more-precise-than-1 ms-resolution sleep to undershoot by a
+    // small amount on the current system, but SDL_DelayNS(0) does at least
+    // introduce a small, yielding delay on many platforms, better than an
+    // unyielding busyloop.
+    //
+    // Note that we'll always do at least one sleep in this function, so the
+    // minimum resolution will be that of SDL_SYS_DelayNS()
+    if (current_value < target_value && (target_value - current_value) > (max_sleep_ns - SHORT_SLEEP_NS)) {
+        const Uint64 delay_ns = (target_value - current_value) - (max_sleep_ns - SHORT_SLEEP_NS);
+        SDL_SYS_DelayNS(delay_ns);
+        current_value = SDL_GetTicksNS();
+    }
+
+    // We've likely undershot target_value at this point by a pretty small
+    // amount, but maybe not. The footgun case if not handled here is where
+    // we've undershot by a large amount, like several ms, but still smaller
+    // than the amount max_sleep_ns overshot by; in such a situation, the above
+    // shorter-sleep block didn't do any delay, the if-block wasn't entered.
+    // Also, maybe the shorter-sleep undershot by several ms, so we still don't
+    // want to spin a lot then. In such a case, we accept the possibility of
+    // overshooting to not spin much, or if overshot here, not at all, keeping
+    // CPU/power usage down in any case. Due to scheduler sloppiness, it's
+    // entirely possible to end up undershooting/overshooting here by much less
+    // than 1 ms even if the current system's sleep function is only 1
+    // ms-resolution, as SDL_GetTicksNS() generally is better resolution than 1
+    // ms on the systems SDL supports.
+    while (current_value + SHORT_SLEEP_NS < target_value) {
+        SDL_SYS_DelayNS(SHORT_SLEEP_NS);
+        current_value = SDL_GetTicksNS();
+    }
+
+    // Spin for any remaining time
+    while (current_value < target_value) {
+        SDL_CPUPauseInstruction();
+        current_value = SDL_GetTicksNS();
+    }
+}