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 *****************************************************************************/
34 #include <time.h> /* clock_gettime(), clock_nanosleep() */
39 #if defined( PTH_INIT_IN_PTH_H ) /* GNU Pth */
44 # include <unistd.h> /* select() */
47 #ifdef HAVE_KERNEL_OS_H
48 # include <kernel/OS.h>
51 #if defined( WIN32 ) || defined( UNDER_CE )
54 #if defined(HAVE_SYS_TIME_H)
55 # include <sys/time.h>
58 #if !defined(HAVE_STRUCT_TIMESPEC)
66 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
67 int nanosleep(struct timespec *, struct timespec *);
70 #ifdef HAVE_CLOCK_NANOSLEEP
71 # if !defined _POSIX_CLOCK_SELECTION || (_POSIX_CLOCK_SELECTION - 0 <= 0)
73 * We cannot use the monotonic clock is clock selection is not available,
74 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
75 * stick to the realtime clock. Nevermind it screws everything when ntpdate
76 * warps the wall clock.
78 # undef CLOCK_MONOTONIC
79 # define CLOCK_MONOTONIC CLOCK_REALTIME
84 * Return a date in a readable format
86 * This function converts a mtime date into a string.
87 * psz_buffer should be a buffer long enough to store the formatted
89 * \param date to be converted
90 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
91 * \return psz_buffer is returned so this can be used as printf parameter.
93 char *mstrtime( char *psz_buffer, mtime_t date )
95 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
97 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
98 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
99 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
100 (int) (date / (ll1000 * ll1000) % ll60),
101 (int) (date / ll1000 % ll1000),
102 (int) (date % ll1000) );
103 return( psz_buffer );
107 * Convert seconds to a time in the format h:mm:ss.
109 * This function is provided for any interface function which need to print a
110 * time string in the format h:mm:ss
112 * \param secs the date to be converted
113 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
114 * \return psz_buffer is returned so this can be used as printf parameter.
116 char *secstotimestr( char *psz_buffer, int i_seconds )
119 i_mins = i_seconds / 60;
120 i_hours = i_mins / 60 ;
123 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
126 (int) (i_seconds % 60) );
130 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
132 (int) (i_seconds % 60) );
134 return( psz_buffer );
138 * Return a value that is no bigger than the clock precision
141 static inline unsigned mprec( void )
143 #if defined (HAVE_CLOCK_NANOSLEEP)
145 if( clock_getres( CLOCK_MONOTONIC, &ts ))
146 clock_getres( CLOCK_REALTIME, &ts );
148 return ts.tv_nsec / 1000;
153 static unsigned prec = 0;
154 static volatile mtime_t cached_time = 0;
157 * Return high precision date
159 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
160 * ftime() function (1 kHz resolution).
162 mtime_t mdate( void )
166 #if defined (HAVE_CLOCK_NANOSLEEP)
169 /* Try to use POSIX monotonic clock if available */
170 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
171 /* Run-time fallback to real-time clock (always available) */
172 (void)clock_gettime( CLOCK_REALTIME, &ts );
174 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
175 + (mtime_t)(ts.tv_nsec / 1000);
177 #elif defined( HAVE_KERNEL_OS_H )
178 res = real_time_clock_usecs();
180 #elif defined( WIN32 ) || defined( UNDER_CE )
181 /* We don't need the real date, just the value of a high precision timer */
182 static mtime_t freq = I64C(-1);
184 if( freq == I64C(-1) )
186 /* Extract from the Tcl source code:
187 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
189 * Some hardware abstraction layers use the CPU clock
190 * in place of the real-time clock as a performance counter
191 * reference. This results in:
192 * - inconsistent results among the processors on
193 * multi-processor systems.
194 * - unpredictable changes in performance counter frequency
195 * on "gearshift" processors such as Transmeta and
197 * There seems to be no way to test whether the performance
198 * counter is reliable, but a useful heuristic is that
199 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
200 * derived from a colorburst crystal and is therefore
201 * the RTC rather than the TSC. If it's anything else, we
202 * presume that the performance counter is unreliable.
206 freq = ( QueryPerformanceFrequency( &buf ) &&
207 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
213 LARGE_INTEGER counter;
214 QueryPerformanceCounter (&counter);
216 /* Convert to from (1/freq) to microsecond resolution */
217 /* We need to split the division to avoid 63-bits overflow */
218 lldiv_t d = lldiv (counter.QuadPart, freq);
220 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
224 /* Fallback on GetTickCount() which has a milisecond resolution
225 * (actually, best case is about 10 ms resolution)
226 * GetTickCount() only returns a DWORD thus will wrap after
227 * about 49.7 days so we try to detect the wrapping. */
229 static CRITICAL_SECTION date_lock;
230 static mtime_t i_previous_time = I64C(-1);
231 static int i_wrap_counts = -1;
233 if( i_wrap_counts == -1 )
236 i_previous_time = I64C(1000) * GetTickCount();
237 InitializeCriticalSection( &date_lock );
241 EnterCriticalSection( &date_lock );
243 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
244 if( i_previous_time > res )
246 /* Counter wrapped */
248 res += I64C(0x100000000) * 1000;
250 i_previous_time = res;
251 LeaveCriticalSection( &date_lock );
254 struct timeval tv_date;
256 /* gettimeofday() cannot fail given &tv_date is a valid address */
257 (void)gettimeofday( &tv_date, NULL );
258 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
261 return cached_time = res;
267 * This function uses select() and an system date function to wake up at a
268 * precise date. It should be used for process synchronization. If current date
269 * is posterior to wished date, the function returns immediately.
270 * \param date The date to wake up at
272 void mwait( mtime_t date )
277 /* If the deadline is already elapsed, or within the clock precision,
278 * do not even bother the clock. */
279 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
282 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
283 lldiv_t d = lldiv( date, 1000000 );
284 struct timespec ts = { d.quot, d.rem * 1000 };
287 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
291 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
292 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
296 mtime_t delay = date - mdate();
304 * More precise sleep()
306 * Portable usleep() function.
307 * \param delay the amount of time to sleep
309 void msleep( mtime_t delay )
311 mtime_t earlier = cached_time;
313 #if defined( HAVE_CLOCK_NANOSLEEP )
314 lldiv_t d = lldiv( delay, 1000000 );
315 struct timespec ts = { d.quot, d.rem * 1000 };
318 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
321 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
322 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
325 #elif defined( HAVE_KERNEL_OS_H )
328 #elif defined( PTH_INIT_IN_PTH_H )
331 #elif defined( ST_INIT_IN_ST_H )
334 #elif defined( WIN32 ) || defined( UNDER_CE )
335 Sleep( (int) (delay / 1000) );
337 #elif defined( HAVE_NANOSLEEP )
338 struct timespec ts_delay;
340 ts_delay.tv_sec = delay / 1000000;
341 ts_delay.tv_nsec = (delay % 1000000) * 1000;
343 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
346 struct timeval tv_delay;
348 tv_delay.tv_sec = delay / 1000000;
349 tv_delay.tv_usec = delay % 1000000;
351 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
352 * or clock_nanosleep() if this is an issue. */
353 select( 0, NULL, NULL, NULL, &tv_delay );
357 if( cached_time < earlier )
358 cached_time = earlier;
362 * Date management (internal and external)
366 * Initialize a date_t.
368 * \param date to initialize
369 * \param divider (sample rate) numerator
370 * \param divider (sample rate) denominator
373 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
376 p_date->i_divider_num = i_divider_n;
377 p_date->i_divider_den = i_divider_d;
378 p_date->i_remainder = 0;
384 * \param date to change
385 * \param divider (sample rate) numerator
386 * \param divider (sample rate) denominator
389 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
391 p_date->i_divider_num = i_divider_n;
392 p_date->i_divider_den = i_divider_d;
396 * Set the date value of a date_t.
401 void date_Set( date_t *p_date, mtime_t i_new_date )
403 p_date->date = i_new_date;
404 p_date->i_remainder = 0;
408 * Get the date of a date_t
413 mtime_t date_Get( const date_t *p_date )
419 * Move forwards or backwards the date of a date_t.
421 * \param date to move
422 * \param difference value
424 void date_Move( date_t *p_date, mtime_t i_difference )
426 p_date->date += i_difference;
430 * Increment the date and return the result, taking into account
433 * \param date to increment
434 * \param incrementation in number of samples
437 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
439 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
440 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
441 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
443 if( p_date->i_remainder >= p_date->i_divider_num )
445 /* This is Bresenham algorithm. */
446 p_date->date += p_date->i_divider_den;
447 p_date->i_remainder -= p_date->i_divider_num;
453 #ifndef HAVE_GETTIMEOFDAY
458 * Number of micro-seconds between the beginning of the Windows epoch
459 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
461 * This assumes all Win32 compilers have 64-bit support.
463 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
464 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
466 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
469 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
471 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
473 res |= ft->dwLowDateTime;
474 res /= 10; /* from 100 nano-sec periods to usec */
475 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
479 static int gettimeofday (struct timeval *tv, void *tz )
487 GetSystemTimeAsFileTime (&ft);
488 tim = filetime_to_unix_epoch (&ft);
489 tv->tv_sec = (long) (tim / 1000000L);
490 tv->tv_usec = (long) (tim % 1000000L);
499 * @return NTP 64-bits timestamp in host byte order.
501 uint64_t NTPtime64 (void)
504 #if defined (CLOCK_REALTIME)
505 clock_gettime (CLOCK_REALTIME, &ts);
509 gettimeofday (&tv, NULL);
510 ts.tv_sec = tv.tv_sec;
511 ts.tv_nsec = tv.tv_usec * 1000;
515 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
516 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
520 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
521 * No leap seconds during that period since they were not invented yet.
523 assert (t < 0x100000000);
524 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;