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 *);
71 * Return a date in a readable format
73 * This function converts a mtime date into a string.
74 * psz_buffer should be a buffer long enough to store the formatted
76 * \param date to be converted
77 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
78 * \return psz_buffer is returned so this can be used as printf parameter.
80 char *mstrtime( char *psz_buffer, mtime_t date )
82 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
84 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
85 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
86 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
87 (int) (date / (ll1000 * ll1000) % ll60),
88 (int) (date / ll1000 % ll1000),
89 (int) (date % ll1000) );
94 * Convert seconds to a time in the format h:mm:ss.
96 * This function is provided for any interface function which need to print a
97 * time string in the format h:mm:ss
99 * \param secs the 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 *secstotimestr( char *psz_buffer, int i_seconds )
105 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
106 (int) (i_seconds / (60 *60)),
107 (int) ((i_seconds / 60) % 60),
108 (int) (i_seconds % 60) );
109 return( psz_buffer );
113 * Return a value that is no bigger than the clock precision
116 static inline unsigned mprec( void )
118 #if defined (HAVE_CLOCK_NANOSLEEP)
120 if( clock_getres( CLOCK_MONOTONIC, &ts ))
121 clock_getres( CLOCK_REALTIME, &ts );
123 return ts.tv_nsec / 1000;
128 static unsigned prec = 0;
129 static volatile mtime_t cached_time = 0;
130 #if defined( HAVE_CLOCK_NANOSLEEP )
131 # if (_POSIX_MONOTONIC_CLOCK - 0 < 0)
132 # define CLOCK_MONOTONIC CLOCK_REALTIME
137 * Return high precision date
139 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
140 * ftime() function (1 kHz resolution).
142 mtime_t mdate( void )
146 #if defined (HAVE_CLOCK_NANOSLEEP)
149 /* Try to use POSIX monotonic clock if available */
150 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
151 /* Run-time fallback to real-time clock (always available) */
152 (void)clock_gettime( CLOCK_REALTIME, &ts );
154 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
155 + (mtime_t)(ts.tv_nsec / 1000);
157 #elif defined( HAVE_KERNEL_OS_H )
158 res = real_time_clock_usecs();
160 #elif defined( WIN32 ) || defined( UNDER_CE )
161 /* We don't need the real date, just the value of a high precision timer */
162 static mtime_t freq = I64C(-1);
164 if( freq == I64C(-1) )
166 /* Extract from the Tcl source code:
167 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
169 * Some hardware abstraction layers use the CPU clock
170 * in place of the real-time clock as a performance counter
171 * reference. This results in:
172 * - inconsistent results among the processors on
173 * multi-processor systems.
174 * - unpredictable changes in performance counter frequency
175 * on "gearshift" processors such as Transmeta and
177 * There seems to be no way to test whether the performance
178 * counter is reliable, but a useful heuristic is that
179 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
180 * derived from a colorburst crystal and is therefore
181 * the RTC rather than the TSC. If it's anything else, we
182 * presume that the performance counter is unreliable.
186 freq = ( QueryPerformanceFrequency( &buf ) &&
187 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
193 LARGE_INTEGER counter;
194 QueryPerformanceCounter (&counter);
196 /* Convert to from (1/freq) to microsecond resolution */
197 /* We need to split the division to avoid 63-bits overflow */
198 lldiv_t d = lldiv (counter.QuadPart, freq);
200 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
204 /* Fallback on GetTickCount() which has a milisecond resolution
205 * (actually, best case is about 10 ms resolution)
206 * GetTickCount() only returns a DWORD thus will wrap after
207 * about 49.7 days so we try to detect the wrapping. */
209 static CRITICAL_SECTION date_lock;
210 static mtime_t i_previous_time = I64C(-1);
211 static int i_wrap_counts = -1;
213 if( i_wrap_counts == -1 )
216 i_previous_time = I64C(1000) * GetTickCount();
217 InitializeCriticalSection( &date_lock );
221 EnterCriticalSection( &date_lock );
223 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
224 if( i_previous_time > res )
226 /* Counter wrapped */
228 res += I64C(0x100000000) * 1000;
230 i_previous_time = res;
231 LeaveCriticalSection( &date_lock );
234 struct timeval tv_date;
236 /* gettimeofday() cannot fail given &tv_date is a valid address */
237 (void)gettimeofday( &tv_date, NULL );
238 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
241 return cached_time = res;
247 * This function uses select() and an system date function to wake up at a
248 * precise date. It should be used for process synchronization. If current date
249 * is posterior to wished date, the function returns immediately.
250 * \param date The date to wake up at
252 void mwait( mtime_t date )
257 /* If the deadline is already elapsed, or within the clock precision,
258 * do not even bother the clock. */
259 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
262 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
263 lldiv_t d = lldiv( date, 1000000 );
264 struct timespec ts = { d.quot, d.rem * 1000 };
267 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
271 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
272 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
276 mtime_t delay = date - mdate();
284 * More precise sleep()
286 * Portable usleep() function.
287 * \param delay the amount of time to sleep
289 void msleep( mtime_t delay )
291 mtime_t earlier = cached_time;
293 #if defined( HAVE_CLOCK_NANOSLEEP )
294 lldiv_t d = lldiv( delay, 1000000 );
295 struct timespec ts = { d.quot, d.rem * 1000 };
298 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
301 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
302 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
305 #elif defined( HAVE_KERNEL_OS_H )
308 #elif defined( PTH_INIT_IN_PTH_H )
311 #elif defined( ST_INIT_IN_ST_H )
314 #elif defined( WIN32 ) || defined( UNDER_CE )
315 Sleep( (int) (delay / 1000) );
317 #elif defined( HAVE_NANOSLEEP )
318 struct timespec ts_delay;
320 ts_delay.tv_sec = delay / 1000000;
321 ts_delay.tv_nsec = (delay % 1000000) * 1000;
323 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
326 struct timeval tv_delay;
328 tv_delay.tv_sec = delay / 1000000;
329 tv_delay.tv_usec = delay % 1000000;
331 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
332 * or clock_nanosleep() if this is an issue. */
333 select( 0, NULL, NULL, NULL, &tv_delay );
337 if( cached_time < earlier )
338 cached_time = earlier;
342 * Date management (internal and external)
346 * Initialize a date_t.
348 * \param date to initialize
349 * \param divider (sample rate) numerator
350 * \param divider (sample rate) denominator
353 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
356 p_date->i_divider_num = i_divider_n;
357 p_date->i_divider_den = i_divider_d;
358 p_date->i_remainder = 0;
364 * \param date to change
365 * \param divider (sample rate) numerator
366 * \param divider (sample rate) denominator
369 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
371 p_date->i_divider_num = i_divider_n;
372 p_date->i_divider_den = i_divider_d;
376 * Set the date value of a date_t.
381 void date_Set( date_t *p_date, mtime_t i_new_date )
383 p_date->date = i_new_date;
384 p_date->i_remainder = 0;
388 * Get the date of a date_t
393 mtime_t date_Get( const date_t *p_date )
399 * Move forwards or backwards the date of a date_t.
401 * \param date to move
402 * \param difference value
404 void date_Move( date_t *p_date, mtime_t i_difference )
406 p_date->date += i_difference;
410 * Increment the date and return the result, taking into account
413 * \param date to increment
414 * \param incrementation in number of samples
417 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
419 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
420 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
421 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
423 if( p_date->i_remainder >= p_date->i_divider_num )
425 /* This is Bresenham algorithm. */
426 p_date->date += p_date->i_divider_den;
427 p_date->i_remainder -= p_date->i_divider_num;
433 #ifndef HAVE_GETTIMEOFDAY
438 * Number of micro-seconds between the beginning of the Windows epoch
439 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
441 * This assumes all Win32 compilers have 64-bit support.
443 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
444 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
446 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
449 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
451 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
453 res |= ft->dwLowDateTime;
454 res /= 10; /* from 100 nano-sec periods to usec */
455 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
459 static int gettimeofday (struct timeval *tv, void *tz )
467 GetSystemTimeAsFileTime (&ft);
468 tim = filetime_to_unix_epoch (&ft);
469 tv->tv_sec = (long) (tim / 1000000L);
470 tv->tv_usec = (long) (tim % 1000000L);
479 * @return NTP 64-bits timestamp in host byte order.
481 uint64_t NTPtime64 (void)
484 #if defined (CLOCK_REALTIME)
485 clock_gettime (CLOCK_REALTIME, &ts);
489 gettimeofday (&tv, NULL);
490 ts.tv_sec = tv.tv_sec;
491 ts.tv_nsec = tv.tv_usec * 1000;
495 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
496 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
500 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
501 * No leap seconds during that period since they were not invented yet.
503 assert (t < 0x100000000);
504 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;