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timer: Added SDL_GetTicks64(), for a timer that doesn't wrap every ~49 days. 

Note that this removes the timeGetTime() fallback on Windows; it is a
32-bit counter and SDL2 should never choose to use it, as it only is needed
if QueryPerformanceCounter() isn't available, and QPC is _always_ available
on Windows XP and later.

OS/2 has a similar situation, but since it isn't clear to me that similar
promises can be made about DosTmrQueryTime() even in modern times, I decided
to leave the fallback in, with some heroic measures added to try to provide a
true 64-bit tick counter despite the 49-day wraparound. That approach can
migrate to Windows too, if we discover some truly broken install that doesn't
have QPC and still depends on timeGetTime().

Fixes #4870.
This commit is contained in:
Ryan C. Gordon 2021-10-23 15:00:31 -04:00
parent 0d631c741f
commit 99c9727dc0
11 changed files with 128 additions and 97 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
include/SDL_timer.h
View File

@ -42,6 +42,10 @@ extern "C" {
*
* This value wraps if the program runs for more than ~49 days.
*
* \deprecated This function is deprecated as of SDL 2.0.18; use
* SDL_GetTicks64() instead, where the value doesn't wrap
* every ~49 days.
*
* \returns an unsigned 32-bit value representing the number of milliseconds
* since the SDL library initialized.
*
@ -49,15 +53,42 @@ extern "C" {
*
* \sa SDL_TICKS_PASSED
*/
extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
extern SDL_DEPRECATED DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);
/**
* Compare SDL ticks values, and return true if `A` has passed `B`.
* Get the number of milliseconds since SDL library initialization.
*
* Note that you should not use the SDL_TICKS_PASSED macro with values
* returned by this function, as that macro does clever math to compensate
* for the 32-bit overflow every ~49 days. 64-bit values can just be safely
* compared directly.
*
* For example, if you want to wait 100 ms, you could do this:
*
* ```c++
* Uint32 timeout = SDL_GetTicks() + 100;
* ```c
* const Uint64 timeout = SDL_GetTicks64() + 100;
* while (SDL_GetTicks64() < timeout) {
* // ... do work until timeout has elapsed
* }
* ```
*
* \returns an unsigned 64-bit value representing the number of milliseconds
* since the SDL library initialized.
*/
extern DECLSPEC Uint64 SDLCALL SDL_GetTicks64(void);
/**
* Compare 32-bit SDL ticks values, and return true if `A` has passed `B`.
*
* This should be used with results from SDL_GetTicks(), as this macro
* attempts to deal with the 32-bit counter wrapping back to zero every ~49
* days, but should _not_ be used with SDL_GetTicks64(), which does not have
* that problem.
*
* For example, if you want to wait 100 ms, you could do this:
*
* ```c
* const Uint32 timeout = SDL_GetTicks() + 100;
* while (!SDL_TICKS_PASSED(SDL_GetTicks(), timeout)) {
* // ... do work until timeout has elapsed
* }

1
src/dynapi/SDL_dynapi_overrides.h
View File

@ -823,3 +823,4 @@
#define SDL_asprintf SDL_asprintf_REAL
#define SDL_vasprintf SDL_vasprintf_REAL
#define SDL_GetWindowICCProfile SDL_GetWindowICCProfile_REAL
#define SDL_GetTicks64 SDL_GetTicks64_REAL

1
src/dynapi/SDL_dynapi_procs.h
View File

@ -890,3 +890,4 @@ SDL_DYNAPI_PROC(int,SDL_asprintf,(char **a, SDL_PRINTF_FORMAT_STRING const char
#endif
SDL_DYNAPI_PROC(int,SDL_vasprintf,(char **a, const char *b, va_list c),(a,b,c),return)
SDL_DYNAPI_PROC(void*,SDL_GetWindowICCProfile,(SDL_Window *a, size_t *b),(a,b),return)
SDL_DYNAPI_PROC(Uint64,SDL_GetTicks64,(void),(),return)

10
src/timer/SDL_timer.c
View File

@ -370,4 +370,14 @@ SDL_RemoveTimer(SDL_TimerID id)
return canceled;
}
/* This is a legacy support function; SDL_GetTicks() returns a Uint32,
which wraps back to zero every ~49 days. The newer SDL_GetTicks64()
doesn't have this problem, so we just wrap that function and clamp to
the low 32-bits for binary compatibility. */
Uint32
SDL_GetTicks(void)
{
return (Uint32) (SDL_GetTicks64() & 0xFFFFFFFF);
}
/* vi: set ts=4 sw=4 expandtab: */

4
src/timer/dummy/SDL_systimer.c
View File

@ -41,8 +41,8 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32
SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
if (!ticks_started) {
SDL_TicksInit();

6
src/timer/haiku/SDL_systimer.c
View File

@ -47,14 +47,14 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32
SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
if (!ticks_started) {
SDL_TicksInit();
}
return ((system_time() - start) / 1000);
return (Uint64) ((system_time() - start) / 1000);
}
Uint64

46
src/timer/os2/SDL_systimer.c
View File

@ -40,25 +40,31 @@
typedef unsigned long long ULLONG;
static ULONG ulTmrFreq = 0;
static ULLONG ullTmrStart;
static ULLONG ullTmrStart = 0;
/* 32-bit counter fallback...not used if DosTmrQuery* is functioning. */
static ULONG ulPrevTmr = 0;
static Uint64 ui64TmrStartOffset = 0; /* Used if 32-bit counter overflows. */
void
SDL_TicksInit(void)
{
ULONG ulRC;
ulRC = DosTmrQueryFreq(&ulTmrFreq);
ULONG ulTmrStart; /* for 32-bit fallback. */
ULONG ulRC = DosTmrQueryFreq(&ulTmrFreq);
if (ulRC != NO_ERROR) {
debug_os2("DosTmrQueryFreq() failed, rc = %u", ulRC);
} else {
ulRC = DosTmrQueryTime((PQWORD)&ullTmrStart);
if (ulRC == NO_ERROR)
if (ulRC == NO_ERROR) {
return;
}
debug_os2("DosTmrQueryTime() failed, rc = %u", ulRC);
}
ulTmrFreq = 0; /* Error - use DosQuerySysInfo() for timer. */
DosQuerySysInfo(QSV_MS_COUNT, QSV_MS_COUNT, (PULONG)&ullTmrStart, sizeof(ULONG));
DosQuerySysInfo(QSV_MS_COUNT, QSV_MS_COUNT, &ulTmrStart, sizeof (ULONG));
ullTmrStart = (ULLONG) ulTmrStart;
ulPrevTmr = ulTmrStart;
}
void
@ -66,24 +72,32 @@ SDL_TicksQuit(void)
{
}
Uint32
SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
ULONG ulResult;
ULLONG ullTmrNow;
Uint64 ui64Result;
ULLONG ullTmrNow;
if (ulTmrFreq == 0) /* Was not initialized. */
if (ulTmrFreq == 0) { /* Was not initialized. */
SDL_TicksInit();
}
if (ulTmrFreq != 0) {
DosTmrQueryTime((PQWORD)&ullTmrNow);
ulResult = (ullTmrNow - ullTmrStart) * 1000 / ulTmrFreq;
ui64Result = (ullTmrNow - ullTmrStart) * 1000 / ulTmrFreq;
} else {
DosQuerySysInfo(QSV_MS_COUNT, QSV_MS_COUNT, (PULONG)&ullTmrNow, sizeof(ULONG));
ulResult = (ULONG)ullTmrNow - (ULONG)ullTmrStart;
ULONG ulTmrNow;
DosQuerySysInfo(QSV_MS_COUNT, QSV_MS_COUNT, &ulTmrNow, sizeof (ULONG));
if ( ((ULLONG) ulTmrNow) < ulPrevTmr ) { /* have we overflowed the 32-bit counter since last check? */
/* Note that this is incorrect if you went more than ~98 days between calls to SDL_GetTicks64(). */
/* One could query QSV_TIME_HIGH and QSV_TIME_LOW here to verify, but it's probably not worth it. */
ui64TmrStartOffset += 0xFFFFFFFF;
}
ui64Result = (((Uint64) ulTmrNow) - ullTmrStart) + ui64TmrStartOffset;
ulPrevTmr = ulTmrNow;
}
return ulResult;
return ui64Result;
}
Uint64
@ -92,7 +106,7 @@ SDL_GetPerformanceCounter(void)
QWORD qwTmrNow;
if (ulTmrFreq == 0 || (DosTmrQueryTime(&qwTmrNow) != NO_ERROR))
return SDL_GetTicks();
return SDL_GetTicks64();
return *((Uint64 *)&qwTmrNow);
}

13
src/timer/psp/SDL_systimer.c
View File

@ -51,24 +51,23 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32 SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
struct timeval now;
if (!ticks_started) {
SDL_TicksInit();
}
struct timeval now;
Uint32 ticks;
gettimeofday(&now, NULL);
ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;
return(ticks);
return (((Uint64)(now.tv_sec-start.tv_sec)) * 1000) + (((Uint64) (now.tv_usec-start.tv_usec)) / 1000);
}
Uint64
SDL_GetPerformanceCounter(void)
{
return SDL_GetTicks();
return SDL_GetTicks64();
}
Uint64

32
src/timer/unix/SDL_systimer.c
View File

@ -104,10 +104,11 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32
Uint64
SDL_GetTicks(void)
{
Uint32 ticks;
struct timeval now;
if (!ticks_started) {
SDL_TicksInit();
}
@ -116,21 +117,18 @@ SDL_GetTicks(void)
#if HAVE_CLOCK_GETTIME
struct timespec now;
clock_gettime(SDL_MONOTONIC_CLOCK, &now);
ticks = (Uint32)((now.tv_sec - start_ts.tv_sec) * 1000 + (now.tv_nsec - start_ts.tv_nsec) / 1000000);
ticks = (((Uint64) (now.tv_sec - start_ts.tv_sec)) * 1000) + (((Uint64) (now.tv_nsec - start_ts.tv_nsec)) / 1000000);
#elif defined(__APPLE__)
uint64_t now = mach_absolute_time();
ticks = (Uint32)((((now - start_mach) * mach_base_info.numer) / mach_base_info.denom) / 1000000);
const uint64_t now = mach_absolute_time();
return (Uint64) ((((now - start_mach) * mach_base_info.numer) / mach_base_info.denom) / 1000000);
#else
SDL_assert(SDL_FALSE);
ticks = 0;
return 0;
#endif
} else {
struct timeval now;
gettimeofday(&now, NULL);
ticks = (Uint32)((now.tv_sec - start_tv.tv_sec) * 1000 + (now.tv_usec - start_tv.tv_usec) / 1000);
}
return (ticks);
gettimeofday(&now, NULL);
return (((Uint64) (now.tv_sec - start_tv.tv_sec)) * 1000) + (((Uint64) (now.tv_usec - start_tv.tv_usec)) / 1000);
}
Uint64
@ -203,7 +201,7 @@ SDL_Delay(Uint32 ms)
struct timespec elapsed, tv;
#else
struct timeval tv;
Uint32 then, now, elapsed;
Uint64 then, now, elapsed;
#endif
/* Set the timeout interval */
@ -211,7 +209,7 @@ SDL_Delay(Uint32 ms)
elapsed.tv_sec = ms / 1000;
elapsed.tv_nsec = (ms % 1000) * 1000000;
#else
then = SDL_GetTicks();
then = SDL_GetTicks64();
#endif
do {
errno = 0;
@ -222,13 +220,13 @@ SDL_Delay(Uint32 ms)
was_error = nanosleep(&tv, &elapsed);
#else
/* Calculate the time interval left (in case of interrupt) */
now = SDL_GetTicks();
now = SDL_GetTicks64();
elapsed = (now - then);
then = now;
if (elapsed >= ms) {
if (elapsed >= ((Uint64) ms)) {
break;
}
ms -= elapsed;
ms -= (Uint32) elapsed;
tv.tv_sec = ms / 1000;
tv.tv_usec = (ms % 1000) * 1000;

7
src/timer/vita/SDL_systimer.c
View File

@ -51,18 +51,17 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32 SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
uint64_t now;
Uint32 ticks;
if (!ticks_started) {
SDL_TicksInit();
}
now = sceKernelGetProcessTimeWide();
ticks = (now - start)/1000;
return (ticks);
return (Uint64) ((now - start) / 1000);
}
Uint64

66
src/timer/windows/SDL_systimer.c
View File

@ -33,12 +33,10 @@
static DWORD start = 0;
static BOOL ticks_started = FALSE;
/* Store if a high-resolution performance counter exists on the system */
static BOOL hires_timer_available;
/* The first high-resolution ticks value of the application */
static LARGE_INTEGER hires_start_ticks;
static LARGE_INTEGER start_ticks;
/* The number of ticks per second of the high-resolution performance counter */
static LARGE_INTEGER hires_ticks_per_second;
static LARGE_INTEGER ticks_per_second;
static void
SDL_SetSystemTimerResolution(const UINT uPeriod)
@ -79,6 +77,8 @@ SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValu
void
SDL_TicksInit(void)
{
BOOL rc;
if (ticks_started) {
return;
}
@ -90,18 +90,12 @@ SDL_TicksInit(void)
SDL_TimerResolutionChanged, NULL);
/* Set first ticks value */
/* QueryPerformanceCounter has had problems in the past, but lots of games
use it, so we'll rely on it here.
/* QueryPerformanceCounter allegedly is always available and reliable as of WinXP,
so we'll rely on it here.
*/
if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
hires_timer_available = TRUE;
QueryPerformanceCounter(&hires_start_ticks);
} else {
hires_timer_available = FALSE;
#ifndef __WINRT__
start = timeGetTime();
#endif /* __WINRT__ */
}
rc = QueryPerformanceFrequency(&ticks_per_second);
SDL_assert(rc != 0); /* this should _never_ fail if you're on XP or later. */
QueryPerformanceCounter(&start_ticks);
}
void
@ -116,53 +110,37 @@ SDL_TicksQuit(void)
ticks_started = SDL_FALSE;
}
Uint32
SDL_GetTicks(void)
Uint64
SDL_GetTicks64(void)
{
DWORD now = 0;
LARGE_INTEGER hires_now;
LARGE_INTEGER now;
BOOL rc;
if (!ticks_started) {
SDL_TicksInit();
}
if (hires_timer_available) {
QueryPerformanceCounter(&hires_now);
hires_now.QuadPart -= hires_start_ticks.QuadPart;
hires_now.QuadPart *= 1000;
hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
return (DWORD) hires_now.QuadPart;
} else {
#ifndef __WINRT__
now = timeGetTime();
#endif /* __WINRT__ */
}
return (now - start);
rc = QueryPerformanceCounter(&now);
SDL_assert(rc != 0); /* this should _never_ fail if you're on XP or later. */
return (Uint64) (((now.QuadPart - start_ticks.QuadPart) * 1000) / ticks_per_second.QuadPart);
}
Uint64
SDL_GetPerformanceCounter(void)
{
LARGE_INTEGER counter;
if (!QueryPerformanceCounter(&counter)) {
return SDL_GetTicks();
}
return counter.QuadPart;
const BOOL rc = QueryPerformanceCounter(&counter);
SDL_assert(rc != 0); /* this should _never_ fail if you're on XP or later. */
return (Uint64) counter.QuadPart;
}
Uint64
SDL_GetPerformanceFrequency(void)
{
LARGE_INTEGER frequency;
if (!QueryPerformanceFrequency(&frequency)) {
return 1000;
}
return frequency.QuadPart;
const BOOL rc = QueryPerformanceFrequency(&frequency);
SDL_assert(rc != 0); /* this should _never_ fail if you're on XP or later. */
return (Uint64) frequency.QuadPart;
}
void