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 *****************************************************************************/
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( UNDER_CE )
59 #if defined(HAVE_SYS_TIME_H)
60 # include <sys/time.h>
63 #if !defined(HAVE_STRUCT_TIMESPEC)
71 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
72 int nanosleep(struct timespec *, struct timespec *);
75 #if !defined (_POSIX_CLOCK_SELECTION)
76 # define _POSIX_CLOCK_SELECTION (-1)
79 # if (_POSIX_CLOCK_SELECTION < 0)
81 * We cannot use the monotonic clock is clock selection is not available,
82 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
83 * stick to the realtime clock. Nevermind it screws everything when ntpdate
84 * warps the wall clock.
86 # undef CLOCK_MONOTONIC
87 # define CLOCK_MONOTONIC CLOCK_REALTIME
88 #elif !defined (HAVE_CLOCK_NANOSLEEP)
89 /* Clock selection without clock in the first place, I don't think so. */
90 # error We have quite a situation here! Fix me if it ever happens.
94 * Return a date in a readable format
96 * This function converts a mtime date into a string.
97 * psz_buffer should be a buffer long enough to store the formatted
99 * \param date to be converted
100 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
101 * \return psz_buffer is returned so this can be used as printf parameter.
103 char *mstrtime( char *psz_buffer, mtime_t date )
105 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
107 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
108 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
109 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
110 (int) (date / (ll1000 * ll1000) % ll60),
111 (int) (date / ll1000 % ll1000),
112 (int) (date % ll1000) );
113 return( psz_buffer );
117 * Convert seconds to a time in the format h:mm:ss.
119 * This function is provided for any interface function which need to print a
120 * time string in the format h:mm:ss
122 * \param secs the date to be converted
123 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
124 * \return psz_buffer is returned so this can be used as printf parameter.
126 char *secstotimestr( char *psz_buffer, int i_seconds )
129 i_mins = i_seconds / 60;
130 i_hours = i_mins / 60 ;
133 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
136 (int) (i_seconds % 60) );
140 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
142 (int) (i_seconds % 60) );
144 return( psz_buffer );
147 #if defined (HAVE_CLOCK_NANOSLEEP)
148 static unsigned prec = 0;
150 static void mprec_once( void )
153 if( clock_getres( CLOCK_MONOTONIC, &ts ))
154 clock_getres( CLOCK_REALTIME, &ts );
156 prec = ts.tv_nsec / 1000;
161 * Return a value that is no bigger than the clock precision
164 static inline unsigned mprec( void )
166 #if defined (HAVE_CLOCK_NANOSLEEP)
167 static pthread_once_t once = PTHREAD_ONCE_INIT;
168 pthread_once( &once, mprec_once );
175 static volatile mtime_t cached_time = 0;
178 * Return high precision date
180 * Use a 1 MHz clock when possible, or 1 kHz
182 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
184 mtime_t mdate( void )
188 #if defined (HAVE_CLOCK_NANOSLEEP)
191 /* Try to use POSIX monotonic clock if available */
192 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
193 /* Run-time fallback to real-time clock (always available) */
194 (void)clock_gettime( CLOCK_REALTIME, &ts );
196 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
197 + (mtime_t)(ts.tv_nsec / 1000);
199 #elif defined( HAVE_KERNEL_OS_H )
200 res = real_time_clock_usecs();
202 #elif defined( WIN32 ) || defined( UNDER_CE )
203 /* We don't need the real date, just the value of a high precision timer */
204 static mtime_t freq = INT64_C(-1);
206 if( freq == INT64_C(-1) )
208 /* Extract from the Tcl source code:
209 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
211 * Some hardware abstraction layers use the CPU clock
212 * in place of the real-time clock as a performance counter
213 * reference. This results in:
214 * - inconsistent results among the processors on
215 * multi-processor systems.
216 * - unpredictable changes in performance counter frequency
217 * on "gearshift" processors such as Transmeta and
219 * There seems to be no way to test whether the performance
220 * counter is reliable, but a useful heuristic is that
221 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
222 * derived from a colorburst crystal and is therefore
223 * the RTC rather than the TSC. If it's anything else, we
224 * presume that the performance counter is unreliable.
228 freq = ( QueryPerformanceFrequency( &buf ) &&
229 (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
233 /* on windows 2000, XP and Vista detect if there are two
234 cores there - that makes QueryPerformanceFrequency in
235 any case not trustable?
236 (may also be true, for single cores with adaptive
237 CPU frequency and active power management?)
239 HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
242 void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
243 pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
244 GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
247 SYSTEM_INFO system_info;
248 pf_GetSystemInfo(&system_info);
249 if(system_info.dwNumberOfProcessors > 1)
252 FreeLibrary(h_Kernel32);
259 LARGE_INTEGER counter;
260 QueryPerformanceCounter (&counter);
262 /* Convert to from (1/freq) to microsecond resolution */
263 /* We need to split the division to avoid 63-bits overflow */
264 lldiv_t d = lldiv (counter.QuadPart, freq);
266 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
270 /* Fallback on timeGetTime() which has a milisecond resolution
271 * (actually, best case is about 5 ms resolution)
272 * timeGetTime() only returns a DWORD thus will wrap after
273 * about 49.7 days so we try to detect the wrapping. */
275 static CRITICAL_SECTION date_lock;
276 static mtime_t i_previous_time = INT64_C(-1);
277 static int i_wrap_counts = -1;
279 if( i_wrap_counts == -1 )
283 i_previous_time = INT64_C(1000) * timeGetTime();
285 i_previous_time = INT64_C(1000) * GetTickCount();
287 InitializeCriticalSection( &date_lock );
291 EnterCriticalSection( &date_lock );
293 res = INT64_C(1000) *
294 (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
296 res = INT64_C(1000) *
297 (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
299 if( i_previous_time > res )
301 /* Counter wrapped */
303 res += INT64_C(0x100000000) * 1000;
305 i_previous_time = res;
306 LeaveCriticalSection( &date_lock );
309 struct timeval tv_date;
311 /* gettimeofday() cannot fail given &tv_date is a valid address */
312 (void)gettimeofday( &tv_date, NULL );
313 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
316 return cached_time = res;
322 * This function uses select() and an system date function to wake up at a
323 * precise date. It should be used for process synchronization. If current date
324 * is posterior to wished date, the function returns immediately.
325 * \param date The date to wake up at
327 void mwait( mtime_t date )
329 /* If the deadline is already elapsed, or within the clock precision,
330 * do not even bother the clock. */
331 if( ( date - cached_time ) < (mtime_t)mprec() ) // OK: mtime_t is signed
334 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
335 lldiv_t d = lldiv( date, 1000000 );
336 struct timespec ts = { d.quot, d.rem * 1000 };
339 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
343 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
344 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
348 mtime_t delay = date - mdate();
356 * More precise sleep()
358 * Portable usleep() function.
359 * \param delay the amount of time to sleep
361 void msleep( mtime_t delay )
363 mtime_t earlier = cached_time;
365 #if defined( HAVE_CLOCK_NANOSLEEP )
366 lldiv_t d = lldiv( delay, 1000000 );
367 struct timespec ts = { d.quot, d.rem * 1000 };
370 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
373 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
374 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
377 #elif defined( HAVE_KERNEL_OS_H )
380 #elif defined( WIN32 ) || defined( UNDER_CE )
381 Sleep( (DWORD) (delay / 1000) );
383 #elif defined( HAVE_NANOSLEEP )
384 struct timespec ts_delay;
386 ts_delay.tv_sec = delay / 1000000;
387 ts_delay.tv_nsec = (delay % 1000000) * 1000;
389 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
392 struct timeval tv_delay;
394 tv_delay.tv_sec = delay / 1000000;
395 tv_delay.tv_usec = delay % 1000000;
397 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
398 * or clock_nanosleep() if this is an issue. */
399 select( 0, NULL, NULL, NULL, &tv_delay );
403 if( cached_time < earlier )
404 cached_time = earlier;
408 * Date management (internal and external)
412 * Initialize a date_t.
414 * \param date to initialize
415 * \param divider (sample rate) numerator
416 * \param divider (sample rate) denominator
419 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
422 p_date->i_divider_num = i_divider_n;
423 p_date->i_divider_den = i_divider_d;
424 p_date->i_remainder = 0;
430 * \param date to change
431 * \param divider (sample rate) numerator
432 * \param divider (sample rate) denominator
435 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
437 p_date->i_divider_num = i_divider_n;
438 p_date->i_divider_den = i_divider_d;
442 * Set the date value of a date_t.
447 void date_Set( date_t *p_date, mtime_t i_new_date )
449 p_date->date = i_new_date;
450 p_date->i_remainder = 0;
454 * Get the date of a date_t
459 mtime_t date_Get( const date_t *p_date )
465 * Move forwards or backwards the date of a date_t.
467 * \param date to move
468 * \param difference value
470 void date_Move( date_t *p_date, mtime_t i_difference )
472 p_date->date += i_difference;
476 * Increment the date and return the result, taking into account
479 * \param date to increment
480 * \param incrementation in number of samples
483 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
485 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
486 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
487 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
489 if( p_date->i_remainder >= p_date->i_divider_num )
491 /* This is Bresenham algorithm. */
492 p_date->date += p_date->i_divider_den;
493 p_date->i_remainder -= p_date->i_divider_num;
499 #ifndef HAVE_GETTIMEOFDAY
504 * Number of micro-seconds between the beginning of the Windows epoch
505 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
507 * This assumes all Win32 compilers have 64-bit support.
509 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
510 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
512 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
515 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
517 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
519 res |= ft->dwLowDateTime;
520 res /= 10; /* from 100 nano-sec periods to usec */
521 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
525 static int gettimeofday (struct timeval *tv, void *tz )
533 GetSystemTimeAsFileTime (&ft);
534 tim = filetime_to_unix_epoch (&ft);
535 tv->tv_sec = (long) (tim / 1000000L);
536 tv->tv_usec = (long) (tim % 1000000L);
545 * @return NTP 64-bits timestamp in host byte order.
547 uint64_t NTPtime64 (void)
550 #if defined (CLOCK_REALTIME)
551 clock_gettime (CLOCK_REALTIME, &ts);
555 gettimeofday (&tv, NULL);
556 ts.tv_sec = tv.tv_sec;
557 ts.tv_nsec = tv.tv_usec * 1000;
561 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
562 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
566 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
567 * No leap seconds during that period since they were not invented yet.
569 assert (t < 0x100000000);
570 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;