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 )
118 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
119 (int) (i_seconds / (60 *60)),
120 (int) ((i_seconds / 60) % 60),
121 (int) (i_seconds % 60) );
122 return( psz_buffer );
126 * Return a value that is no bigger than the clock precision
129 static inline unsigned mprec( void )
131 #if defined (HAVE_CLOCK_NANOSLEEP)
133 if( clock_getres( CLOCK_MONOTONIC, &ts ))
134 clock_getres( CLOCK_REALTIME, &ts );
136 return ts.tv_nsec / 1000;
141 static unsigned prec = 0;
142 static volatile mtime_t cached_time = 0;
145 * Return high precision date
147 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
148 * ftime() function (1 kHz resolution).
150 mtime_t mdate( void )
154 #if defined (HAVE_CLOCK_NANOSLEEP)
157 /* Try to use POSIX monotonic clock if available */
158 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
159 /* Run-time fallback to real-time clock (always available) */
160 (void)clock_gettime( CLOCK_REALTIME, &ts );
162 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
163 + (mtime_t)(ts.tv_nsec / 1000);
165 #elif defined( HAVE_KERNEL_OS_H )
166 res = real_time_clock_usecs();
168 #elif defined( WIN32 ) || defined( UNDER_CE )
169 /* We don't need the real date, just the value of a high precision timer */
170 static mtime_t freq = I64C(-1);
172 if( freq == I64C(-1) )
174 /* Extract from the Tcl source code:
175 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
177 * Some hardware abstraction layers use the CPU clock
178 * in place of the real-time clock as a performance counter
179 * reference. This results in:
180 * - inconsistent results among the processors on
181 * multi-processor systems.
182 * - unpredictable changes in performance counter frequency
183 * on "gearshift" processors such as Transmeta and
185 * There seems to be no way to test whether the performance
186 * counter is reliable, but a useful heuristic is that
187 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
188 * derived from a colorburst crystal and is therefore
189 * the RTC rather than the TSC. If it's anything else, we
190 * presume that the performance counter is unreliable.
194 freq = ( QueryPerformanceFrequency( &buf ) &&
195 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
201 LARGE_INTEGER counter;
202 QueryPerformanceCounter (&counter);
204 /* Convert to from (1/freq) to microsecond resolution */
205 /* We need to split the division to avoid 63-bits overflow */
206 lldiv_t d = lldiv (counter.QuadPart, freq);
208 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
212 /* Fallback on GetTickCount() which has a milisecond resolution
213 * (actually, best case is about 10 ms resolution)
214 * GetTickCount() only returns a DWORD thus will wrap after
215 * about 49.7 days so we try to detect the wrapping. */
217 static CRITICAL_SECTION date_lock;
218 static mtime_t i_previous_time = I64C(-1);
219 static int i_wrap_counts = -1;
221 if( i_wrap_counts == -1 )
224 i_previous_time = I64C(1000) * GetTickCount();
225 InitializeCriticalSection( &date_lock );
229 EnterCriticalSection( &date_lock );
231 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
232 if( i_previous_time > res )
234 /* Counter wrapped */
236 res += I64C(0x100000000) * 1000;
238 i_previous_time = res;
239 LeaveCriticalSection( &date_lock );
242 struct timeval tv_date;
244 /* gettimeofday() cannot fail given &tv_date is a valid address */
245 (void)gettimeofday( &tv_date, NULL );
246 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
249 return cached_time = res;
255 * This function uses select() and an system date function to wake up at a
256 * precise date. It should be used for process synchronization. If current date
257 * is posterior to wished date, the function returns immediately.
258 * \param date The date to wake up at
260 void mwait( mtime_t date )
265 /* If the deadline is already elapsed, or within the clock precision,
266 * do not even bother the clock. */
267 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
270 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
271 lldiv_t d = lldiv( date, 1000000 );
272 struct timespec ts = { d.quot, d.rem * 1000 };
275 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
279 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
280 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
284 mtime_t delay = date - mdate();
292 * More precise sleep()
294 * Portable usleep() function.
295 * \param delay the amount of time to sleep
297 void msleep( mtime_t delay )
299 mtime_t earlier = cached_time;
301 #if defined( HAVE_CLOCK_NANOSLEEP )
302 lldiv_t d = lldiv( delay, 1000000 );
303 struct timespec ts = { d.quot, d.rem * 1000 };
306 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
309 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
310 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
313 #elif defined( HAVE_KERNEL_OS_H )
316 #elif defined( PTH_INIT_IN_PTH_H )
319 #elif defined( ST_INIT_IN_ST_H )
322 #elif defined( WIN32 ) || defined( UNDER_CE )
323 Sleep( (int) (delay / 1000) );
325 #elif defined( HAVE_NANOSLEEP )
326 struct timespec ts_delay;
328 ts_delay.tv_sec = delay / 1000000;
329 ts_delay.tv_nsec = (delay % 1000000) * 1000;
331 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
334 struct timeval tv_delay;
336 tv_delay.tv_sec = delay / 1000000;
337 tv_delay.tv_usec = delay % 1000000;
339 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
340 * or clock_nanosleep() if this is an issue. */
341 select( 0, NULL, NULL, NULL, &tv_delay );
345 if( cached_time < earlier )
346 cached_time = earlier;
350 * Date management (internal and external)
354 * Initialize a date_t.
356 * \param date to initialize
357 * \param divider (sample rate) numerator
358 * \param divider (sample rate) denominator
361 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
364 p_date->i_divider_num = i_divider_n;
365 p_date->i_divider_den = i_divider_d;
366 p_date->i_remainder = 0;
372 * \param date to change
373 * \param divider (sample rate) numerator
374 * \param divider (sample rate) denominator
377 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
379 p_date->i_divider_num = i_divider_n;
380 p_date->i_divider_den = i_divider_d;
384 * Set the date value of a date_t.
389 void date_Set( date_t *p_date, mtime_t i_new_date )
391 p_date->date = i_new_date;
392 p_date->i_remainder = 0;
396 * Get the date of a date_t
401 mtime_t date_Get( const date_t *p_date )
407 * Move forwards or backwards the date of a date_t.
409 * \param date to move
410 * \param difference value
412 void date_Move( date_t *p_date, mtime_t i_difference )
414 p_date->date += i_difference;
418 * Increment the date and return the result, taking into account
421 * \param date to increment
422 * \param incrementation in number of samples
425 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
427 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
428 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
429 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
431 if( p_date->i_remainder >= p_date->i_divider_num )
433 /* This is Bresenham algorithm. */
434 p_date->date += p_date->i_divider_den;
435 p_date->i_remainder -= p_date->i_divider_num;
441 #ifndef HAVE_GETTIMEOFDAY
446 * Number of micro-seconds between the beginning of the Windows epoch
447 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
449 * This assumes all Win32 compilers have 64-bit support.
451 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
452 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
454 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
457 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
459 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
461 res |= ft->dwLowDateTime;
462 res /= 10; /* from 100 nano-sec periods to usec */
463 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
467 static int gettimeofday (struct timeval *tv, void *tz )
475 GetSystemTimeAsFileTime (&ft);
476 tim = filetime_to_unix_epoch (&ft);
477 tv->tv_sec = (long) (tim / 1000000L);
478 tv->tv_usec = (long) (tim % 1000000L);
487 * @return NTP 64-bits timestamp in host byte order.
489 uint64_t NTPtime64 (void)
492 #if defined (CLOCK_REALTIME)
493 clock_gettime (CLOCK_REALTIME, &ts);
497 gettimeofday (&tv, NULL);
498 ts.tv_sec = tv.tv_sec;
499 ts.tv_nsec = tv.tv_usec * 1000;
503 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
504 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
508 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
509 * No leap seconds during that period since they were not invented yet.
511 assert (t < 0x100000000);
512 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;