1 /*****************************************************************************
2 * mtime.c: high resolution time management functions
3 * Functions are prototyped in vlc_mtime.h.
4 *****************************************************************************
5 * Copyright (C) 1998-2007 the VideoLAN team
6 * Copyright © 2006-2007 Rémi Denis-Courmont
9 * Authors: Vincent Seguin <seguin@via.ecp.fr>
10 * Rémi Denis-Courmont <rem$videolan,org>
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
26 *****************************************************************************/
28 /*****************************************************************************
30 *****************************************************************************/
36 #include <vlc_common.h>
38 #include <time.h> /* clock_gettime(), clock_nanosleep() */
43 # include <unistd.h> /* select() */
46 #ifdef HAVE_KERNEL_OS_H
47 # include <kernel/OS.h>
50 #if defined( WIN32 ) || defined( UNDER_CE )
52 # include <mmsystem.h>
55 #if defined(HAVE_SYS_TIME_H)
56 # include <sys/time.h>
59 #if defined(__APPLE__) && !defined(__powerpc__) && !defined(__ppc__) && !defined(__ppc64__)
60 #define USE_APPLE_MACH 1
61 # include <mach/mach.h>
62 # include <mach/mach_time.h>
65 #if !defined(HAVE_STRUCT_TIMESPEC)
73 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
74 int nanosleep(struct timespec *, struct timespec *);
77 #if !defined (_POSIX_CLOCK_SELECTION)
78 # define _POSIX_CLOCK_SELECTION (-1)
81 # if (_POSIX_CLOCK_SELECTION < 0)
83 * We cannot use the monotonic clock is clock selection is not available,
84 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
85 * stick to the realtime clock. Nevermind it screws everything when ntpdate
86 * warps the wall clock.
88 # undef CLOCK_MONOTONIC
89 # define CLOCK_MONOTONIC CLOCK_REALTIME
90 #elif !defined (HAVE_CLOCK_NANOSLEEP)
91 /* Clock selection without clock in the first place, I don't think so. */
92 # error We have quite a situation here! Fix me if it ever happens.
96 * Return a date in a readable format
98 * This function converts a mtime date into a string.
99 * psz_buffer should be a buffer long enough to store the formatted
101 * \param date to be converted
102 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
103 * \return psz_buffer is returned so this can be used as printf parameter.
105 char *mstrtime( char *psz_buffer, mtime_t date )
107 static const mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
109 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
110 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
111 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
112 (int) (date / (ll1000 * ll1000) % ll60),
113 (int) (date / ll1000 % ll1000),
114 (int) (date % ll1000) );
115 return( psz_buffer );
119 * Convert seconds to a time in the format h:mm:ss.
121 * This function is provided for any interface function which need to print a
122 * time string in the format h:mm:ss
124 * \param secs the date to be converted
125 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
126 * \return psz_buffer is returned so this can be used as printf parameter.
128 char *secstotimestr( char *psz_buffer, int i_seconds )
131 i_mins = i_seconds / 60;
132 i_hours = i_mins / 60 ;
135 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
138 (int) (i_seconds % 60) );
142 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
144 (int) (i_seconds % 60) );
146 return( psz_buffer );
149 #if defined (HAVE_CLOCK_NANOSLEEP)
150 static unsigned prec = 0;
152 static void mprec_once( void )
155 if( clock_getres( CLOCK_MONOTONIC, &ts ))
156 clock_getres( CLOCK_REALTIME, &ts );
158 prec = ts.tv_nsec / 1000;
163 * Return a value that is no bigger than the clock precision
166 static inline unsigned mprec( void )
168 #if defined (HAVE_CLOCK_NANOSLEEP)
169 static pthread_once_t once = PTHREAD_ONCE_INIT;
170 pthread_once( &once, mprec_once );
177 #ifdef USE_APPLE_MACH
178 static mach_timebase_info_data_t mtime_timebase_info;
179 static pthread_once_t mtime_timebase_info_once = PTHREAD_ONCE_INIT;
180 static void mtime_init_timebase(void)
182 mach_timebase_info(&mtime_timebase_info);
187 * Return high precision date
189 * Use a 1 MHz clock when possible, or 1 kHz
191 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
193 mtime_t mdate( void )
197 #if defined (HAVE_CLOCK_NANOSLEEP)
200 /* Try to use POSIX monotonic clock if available */
201 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
202 /* Run-time fallback to real-time clock (always available) */
203 (void)clock_gettime( CLOCK_REALTIME, &ts );
205 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
206 + (mtime_t)(ts.tv_nsec / 1000);
208 #elif defined( HAVE_KERNEL_OS_H )
209 res = real_time_clock_usecs();
211 #elif defined( USE_APPLE_MACH )
212 pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
213 uint64_t date = mach_absolute_time();
215 /* Convert to nanoseconds */
216 date *= mtime_timebase_info.numer;
217 date /= mtime_timebase_info.denom;
219 /* Convert to microseconds */
221 #elif defined( WIN32 ) || defined( UNDER_CE )
222 /* We don't need the real date, just the value of a high precision timer */
223 static mtime_t freq = INT64_C(-1);
225 if( freq == INT64_C(-1) )
227 /* Extract from the Tcl source code:
228 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
230 * Some hardware abstraction layers use the CPU clock
231 * in place of the real-time clock as a performance counter
232 * reference. This results in:
233 * - inconsistent results among the processors on
234 * multi-processor systems.
235 * - unpredictable changes in performance counter frequency
236 * on "gearshift" processors such as Transmeta and
238 * There seems to be no way to test whether the performance
239 * counter is reliable, but a useful heuristic is that
240 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
241 * derived from a colorburst crystal and is therefore
242 * the RTC rather than the TSC. If it's anything else, we
243 * presume that the performance counter is unreliable.
247 freq = ( QueryPerformanceFrequency( &buf ) &&
248 (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
252 /* on windows 2000, XP and Vista detect if there are two
253 cores there - that makes QueryPerformanceFrequency in
254 any case not trustable?
255 (may also be true, for single cores with adaptive
256 CPU frequency and active power management?)
258 HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
261 void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
262 pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
263 GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
266 SYSTEM_INFO system_info;
267 pf_GetSystemInfo(&system_info);
268 if(system_info.dwNumberOfProcessors > 1)
271 FreeLibrary(h_Kernel32);
278 LARGE_INTEGER counter;
279 QueryPerformanceCounter (&counter);
281 /* Convert to from (1/freq) to microsecond resolution */
282 /* We need to split the division to avoid 63-bits overflow */
283 lldiv_t d = lldiv (counter.QuadPart, freq);
285 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
289 /* Fallback on timeGetTime() which has a millisecond resolution
290 * (actually, best case is about 5 ms resolution)
291 * timeGetTime() only returns a DWORD thus will wrap after
292 * about 49.7 days so we try to detect the wrapping. */
294 static CRITICAL_SECTION date_lock;
295 static mtime_t i_previous_time = INT64_C(-1);
296 static int i_wrap_counts = -1;
298 if( i_wrap_counts == -1 )
302 i_previous_time = INT64_C(1000) * timeGetTime();
304 i_previous_time = INT64_C(1000) * GetTickCount();
306 InitializeCriticalSection( &date_lock );
310 EnterCriticalSection( &date_lock );
312 res = INT64_C(1000) *
313 (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
315 res = INT64_C(1000) *
316 (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
318 if( i_previous_time > res )
320 /* Counter wrapped */
322 res += INT64_C(0x100000000) * 1000;
324 i_previous_time = res;
325 LeaveCriticalSection( &date_lock );
327 #elif USE_APPLE_MACH /* The version that should be used, if it was cancelable */
328 pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
329 uint64_t mach_time = date * 1000 * mtime_timebase_info.denom / mtime_timebase_info.numer;
330 mach_wait_until(mach_time);
333 struct timeval tv_date;
335 /* gettimeofday() cannot fail given &tv_date is a valid address */
336 (void)gettimeofday( &tv_date, NULL );
337 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
347 * This function uses select() and an system date function to wake up at a
348 * precise date. It should be used for process synchronization. If current date
349 * is posterior to wished date, the function returns immediately.
350 * \param date The date to wake up at
352 void mwait( mtime_t date )
354 /* If the deadline is already elapsed, or within the clock precision,
355 * do not even bother the system timer. */
358 #if defined (HAVE_CLOCK_NANOSLEEP)
359 lldiv_t d = lldiv( date, 1000000 );
360 struct timespec ts = { d.quot, d.rem * 1000 };
363 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
367 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
368 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
371 #elif defined (WIN32)
374 while( (i_total = (date - mdate())) > 0 )
376 const mtime_t i_sleep = i_total / 1000;
377 DWORD i_delay = (i_sleep > 0x7fffffff) ? 0x7fffffff : i_sleep;
379 SleepEx( i_delay, TRUE );
384 mtime_t delay = date - mdate();
392 #include "libvlc.h" /* vlc_backtrace() */
396 * Portable usleep(). Cancellation point.
398 * \param delay the amount of time to sleep
400 void msleep( mtime_t delay )
402 #if defined( HAVE_CLOCK_NANOSLEEP )
403 lldiv_t d = lldiv( delay, 1000000 );
404 struct timespec ts = { d.quot, d.rem * 1000 };
407 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
410 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
411 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
414 #elif defined( HAVE_KERNEL_OS_H )
417 #elif defined( WIN32 ) || defined( UNDER_CE )
418 mwait (mdate () + delay);
420 #elif defined( HAVE_NANOSLEEP )
421 struct timespec ts_delay;
423 ts_delay.tv_sec = delay / 1000000;
424 ts_delay.tv_nsec = (delay % 1000000) * 1000;
426 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
428 #elif USE_APPLE_MACH /* The version that should be used, if it was cancelable */
429 pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
430 uint64_t mach_time = delay * 1000 * mtime_timebase_info.denom / mtime_timebase_info.numer;
431 mach_wait_until(mach_time + mach_absolute_time());
434 struct timeval tv_delay;
436 tv_delay.tv_sec = delay / 1000000;
437 tv_delay.tv_usec = delay % 1000000;
439 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
440 * or clock_nanosleep() if this is an issue. */
441 select( 0, NULL, NULL, NULL, &tv_delay );
446 * Date management (internal and external)
450 * Initialize a date_t.
452 * \param date to initialize
453 * \param divider (sample rate) numerator
454 * \param divider (sample rate) denominator
457 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
460 p_date->i_divider_num = i_divider_n;
461 p_date->i_divider_den = i_divider_d;
462 p_date->i_remainder = 0;
468 * \param date to change
469 * \param divider (sample rate) numerator
470 * \param divider (sample rate) denominator
473 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
475 /* change time scale of remainder */
476 p_date->i_remainder = p_date->i_remainder * i_divider_n / p_date->i_divider_num;
477 p_date->i_divider_num = i_divider_n;
478 p_date->i_divider_den = i_divider_d;
482 * Set the date value of a date_t.
487 void date_Set( date_t *p_date, mtime_t i_new_date )
489 p_date->date = i_new_date;
490 p_date->i_remainder = 0;
494 * Get the date of a date_t
499 mtime_t date_Get( const date_t *p_date )
505 * Move forwards or backwards the date of a date_t.
507 * \param date to move
508 * \param difference value
510 void date_Move( date_t *p_date, mtime_t i_difference )
512 p_date->date += i_difference;
516 * Increment the date and return the result, taking into account
519 * \param date to increment
520 * \param incrementation in number of samples
523 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
525 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
526 p_date->date += i_dividend / p_date->i_divider_num;
527 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
529 if( p_date->i_remainder >= p_date->i_divider_num )
531 /* This is Bresenham algorithm. */
532 assert( p_date->i_remainder < 2*p_date->i_divider_num);
534 p_date->i_remainder -= p_date->i_divider_num;
541 * Decrement the date and return the result, taking into account
544 * \param date to decrement
545 * \param decrementation in number of samples
548 mtime_t date_Decrement( date_t *p_date, uint32_t i_nb_samples )
550 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
551 p_date->date -= i_dividend / p_date->i_divider_num;
552 unsigned i_rem_adjust = i_dividend % p_date->i_divider_num;
554 if( p_date->i_remainder < i_rem_adjust )
556 /* This is Bresenham algorithm. */
557 assert( p_date->i_remainder > -p_date->i_divider_num);
559 p_date->i_remainder += p_date->i_divider_num;
562 p_date->i_remainder -= i_rem_adjust;
567 #ifndef HAVE_GETTIMEOFDAY
572 * Number of micro-seconds between the beginning of the Windows epoch
573 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
575 * This assumes all Win32 compilers have 64-bit support.
577 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
578 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
580 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
583 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
585 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
587 res |= ft->dwLowDateTime;
588 res /= 10; /* from 100 nano-sec periods to usec */
589 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
593 static int gettimeofday (struct timeval *tv, void *tz )
601 GetSystemTimeAsFileTime (&ft);
602 tim = filetime_to_unix_epoch (&ft);
603 tv->tv_sec = (long) (tim / 1000000L);
604 tv->tv_usec = (long) (tim % 1000000L);
613 * @return NTP 64-bits timestamp in host byte order.
615 uint64_t NTPtime64 (void)
618 #if defined (CLOCK_REALTIME)
619 clock_gettime (CLOCK_REALTIME, &ts);
623 gettimeofday (&tv, NULL);
624 ts.tv_sec = tv.tv_sec;
625 ts.tv_nsec = tv.tv_usec * 1000;
629 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
630 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
634 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
635 * No leap seconds during that period since they were not invented yet.
637 assert (t < 0x100000000);
638 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;