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 if 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 up 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, int32_t i_seconds )
130 if( unlikely(i_seconds < 0) )
132 secstotimestr( psz_buffer + 1, -i_seconds );
139 d = div( i_seconds, 60 );
141 d = div( d.quot, 60 );
144 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%u:%02u:%02u",
145 d.quot, d.rem, i_seconds );
147 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02u:%02u",
152 #if defined (HAVE_CLOCK_NANOSLEEP)
153 static unsigned prec = 0;
155 static void mprec_once( void )
158 if( clock_getres( CLOCK_MONOTONIC, &ts ))
159 clock_getres( CLOCK_REALTIME, &ts );
161 prec = ts.tv_nsec / 1000;
166 * Return a value that is no bigger than the clock precision
169 static inline unsigned mprec( void )
171 #if defined (HAVE_CLOCK_NANOSLEEP)
172 static pthread_once_t once = PTHREAD_ONCE_INIT;
173 pthread_once( &once, mprec_once );
180 #ifdef USE_APPLE_MACH
181 static mach_timebase_info_data_t mtime_timebase_info;
182 static pthread_once_t mtime_timebase_info_once = PTHREAD_ONCE_INIT;
183 static void mtime_init_timebase(void)
185 mach_timebase_info(&mtime_timebase_info);
190 * Return high precision date
192 * Use a 1 MHz clock when possible, or 1 kHz
194 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
196 mtime_t mdate( void )
200 #if defined (HAVE_CLOCK_NANOSLEEP)
203 /* Try to use POSIX monotonic clock if available */
204 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
205 /* Run-time fallback to real-time clock (always available) */
206 (void)clock_gettime( CLOCK_REALTIME, &ts );
208 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
209 + (mtime_t)(ts.tv_nsec / 1000);
211 #elif defined( HAVE_KERNEL_OS_H )
212 res = real_time_clock_usecs();
214 #elif defined( USE_APPLE_MACH )
215 pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
216 uint64_t date = mach_absolute_time();
217 mach_timebase_info_data_t tb = mtime_timebase_info;
219 /* tb.denom is uint32_t, switch to 64 bits to prevent overflow. */
220 uint64_t denom = tb.denom;
222 /* Switch to microsecs */
225 /* Split the division to prevent overflow */
226 lldiv_t d = lldiv (tb.numer, denom);
228 res = (d.quot * date) + ((d.rem * date) / denom);
230 #elif defined( WIN32 ) || defined( UNDER_CE )
231 /* We don't need the real date, just the value of a high precision timer */
232 LARGE_INTEGER counter, freq;
233 if (!QueryPerformanceCounter (&counter)
234 || !QueryPerformanceFrequency (&freq))
237 /* Convert to from (1/freq) to microsecond resolution */
238 /* We need to split the division to avoid 63-bits overflow */
239 lldiv_t d = lldiv (counter.QuadPart, freq.QuadPart);
241 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq.QuadPart);
244 struct timeval tv_date;
246 /* gettimeofday() cannot fail given &tv_date is a valid address */
247 (void)gettimeofday( &tv_date, NULL );
248 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
258 * This function uses select() and an system date function to wake up at a
259 * precise date. It should be used for process synchronization. If current date
260 * is posterior to wished date, the function returns immediately.
261 * \param date The date to wake up at
263 void mwait( mtime_t date )
265 /* If the deadline is already elapsed, or within the clock precision,
266 * do not even bother the system timer. */
269 #if defined (HAVE_CLOCK_NANOSLEEP)
270 lldiv_t d = lldiv( date, 1000000 );
271 struct timespec ts = { d.quot, d.rem * 1000 };
274 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
278 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
279 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
282 #elif defined (WIN32)
285 while( (i_total = (date - mdate())) > 0 )
287 const mtime_t i_sleep = i_total / 1000;
288 DWORD i_delay = (i_sleep > 0x7fffffff) ? 0x7fffffff : i_sleep;
290 SleepEx( i_delay, TRUE );
295 mtime_t delay = date - mdate();
303 #include "libvlc.h" /* vlc_backtrace() */
307 * Portable usleep(). Cancellation point.
309 * \param delay the amount of time to sleep
311 void msleep( mtime_t delay )
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( WIN32 ) || defined( UNDER_CE )
329 mwait (mdate () + delay);
331 #elif defined( HAVE_NANOSLEEP )
332 struct timespec ts_delay;
334 ts_delay.tv_sec = delay / 1000000;
335 ts_delay.tv_nsec = (delay % 1000000) * 1000;
337 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
339 #elif defined (USE_APPLE_MACH)
340 /* The version that should be used, if it was cancelable */
341 pthread_once(&mtime_timebase_info_once, mtime_init_timebase);
342 uint64_t mach_time = delay * 1000 * mtime_timebase_info.denom / mtime_timebase_info.numer;
343 mach_wait_until(mach_time + mach_absolute_time());
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 );
358 * Date management (internal and external)
362 * Initialize a date_t.
364 * \param date to initialize
365 * \param divider (sample rate) numerator
366 * \param divider (sample rate) denominator
369 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
372 p_date->i_divider_num = i_divider_n;
373 p_date->i_divider_den = i_divider_d;
374 p_date->i_remainder = 0;
380 * \param date to change
381 * \param divider (sample rate) numerator
382 * \param divider (sample rate) denominator
385 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
387 /* change time scale of remainder */
388 p_date->i_remainder = p_date->i_remainder * i_divider_n / p_date->i_divider_num;
389 p_date->i_divider_num = i_divider_n;
390 p_date->i_divider_den = i_divider_d;
394 * Set the date value of a date_t.
399 void date_Set( date_t *p_date, mtime_t i_new_date )
401 p_date->date = i_new_date;
402 p_date->i_remainder = 0;
406 * Get the date of a date_t
411 mtime_t date_Get( const date_t *p_date )
417 * Move forwards or backwards the date of a date_t.
419 * \param date to move
420 * \param difference value
422 void date_Move( date_t *p_date, mtime_t i_difference )
424 p_date->date += i_difference;
428 * Increment the date and return the result, taking into account
431 * \param date to increment
432 * \param incrementation in number of samples
435 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
437 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
438 p_date->date += i_dividend / p_date->i_divider_num;
439 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
441 if( p_date->i_remainder >= p_date->i_divider_num )
443 /* This is Bresenham algorithm. */
444 assert( p_date->i_remainder < 2*p_date->i_divider_num);
446 p_date->i_remainder -= p_date->i_divider_num;
453 * Decrement the date and return the result, taking into account
456 * \param date to decrement
457 * \param decrementation in number of samples
460 mtime_t date_Decrement( date_t *p_date, uint32_t i_nb_samples )
462 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
463 p_date->date -= i_dividend / p_date->i_divider_num;
464 unsigned i_rem_adjust = i_dividend % p_date->i_divider_num;
466 if( p_date->i_remainder < i_rem_adjust )
468 /* This is Bresenham algorithm. */
469 assert( p_date->i_remainder > -p_date->i_divider_num);
471 p_date->i_remainder += p_date->i_divider_num;
474 p_date->i_remainder -= i_rem_adjust;
479 #ifndef HAVE_GETTIMEOFDAY
484 * Number of micro-seconds between the beginning of the Windows epoch
485 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
487 * This assumes all Win32 compilers have 64-bit support.
489 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
490 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
492 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
495 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
497 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
499 res |= ft->dwLowDateTime;
500 res /= 10; /* from 100 nano-sec periods to usec */
501 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
505 static int gettimeofday (struct timeval *tv, void *tz )
513 GetSystemTimeAsFileTime (&ft);
514 tim = filetime_to_unix_epoch (&ft);
515 tv->tv_sec = (long) (tim / 1000000L);
516 tv->tv_usec = (long) (tim % 1000000L);
525 * @return NTP 64-bits timestamp in host byte order.
527 uint64_t NTPtime64 (void)
530 #if defined (CLOCK_REALTIME)
531 clock_gettime (CLOCK_REALTIME, &ts);
535 gettimeofday (&tv, NULL);
536 ts.tv_sec = tv.tv_sec;
537 ts.tv_nsec = tv.tv_usec * 1000;
541 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
542 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
546 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
547 * No leap seconds during that period since they were not invented yet.
549 assert (t < 0x100000000);
550 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;