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( 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 );
176 * Return high precision date
178 * Use a 1 MHz clock when possible, or 1 kHz
180 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
182 mtime_t mdate( void )
186 #if defined (HAVE_CLOCK_NANOSLEEP)
189 /* Try to use POSIX monotonic clock if available */
190 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
191 /* Run-time fallback to real-time clock (always available) */
192 (void)clock_gettime( CLOCK_REALTIME, &ts );
194 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
195 + (mtime_t)(ts.tv_nsec / 1000);
197 #elif defined( HAVE_KERNEL_OS_H )
198 res = real_time_clock_usecs();
200 #elif defined( WIN32 ) || defined( UNDER_CE )
201 /* We don't need the real date, just the value of a high precision timer */
202 static mtime_t freq = INT64_C(-1);
204 if( freq == INT64_C(-1) )
206 /* Extract from the Tcl source code:
207 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
209 * Some hardware abstraction layers use the CPU clock
210 * in place of the real-time clock as a performance counter
211 * reference. This results in:
212 * - inconsistent results among the processors on
213 * multi-processor systems.
214 * - unpredictable changes in performance counter frequency
215 * on "gearshift" processors such as Transmeta and
217 * There seems to be no way to test whether the performance
218 * counter is reliable, but a useful heuristic is that
219 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
220 * derived from a colorburst crystal and is therefore
221 * the RTC rather than the TSC. If it's anything else, we
222 * presume that the performance counter is unreliable.
226 freq = ( QueryPerformanceFrequency( &buf ) &&
227 (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
231 /* on windows 2000, XP and Vista detect if there are two
232 cores there - that makes QueryPerformanceFrequency in
233 any case not trustable?
234 (may also be true, for single cores with adaptive
235 CPU frequency and active power management?)
237 HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
240 void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
241 pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
242 GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
245 SYSTEM_INFO system_info;
246 pf_GetSystemInfo(&system_info);
247 if(system_info.dwNumberOfProcessors > 1)
250 FreeLibrary(h_Kernel32);
257 LARGE_INTEGER counter;
258 QueryPerformanceCounter (&counter);
260 /* Convert to from (1/freq) to microsecond resolution */
261 /* We need to split the division to avoid 63-bits overflow */
262 lldiv_t d = lldiv (counter.QuadPart, freq);
264 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
268 /* Fallback on timeGetTime() which has a milisecond resolution
269 * (actually, best case is about 5 ms resolution)
270 * timeGetTime() only returns a DWORD thus will wrap after
271 * about 49.7 days so we try to detect the wrapping. */
273 static CRITICAL_SECTION date_lock;
274 static mtime_t i_previous_time = INT64_C(-1);
275 static int i_wrap_counts = -1;
277 if( i_wrap_counts == -1 )
281 i_previous_time = INT64_C(1000) * timeGetTime();
283 i_previous_time = INT64_C(1000) * GetTickCount();
285 InitializeCriticalSection( &date_lock );
289 EnterCriticalSection( &date_lock );
291 res = INT64_C(1000) *
292 (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
294 res = INT64_C(1000) *
295 (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
297 if( i_previous_time > res )
299 /* Counter wrapped */
301 res += INT64_C(0x100000000) * 1000;
303 i_previous_time = res;
304 LeaveCriticalSection( &date_lock );
307 struct timeval tv_date;
309 /* gettimeofday() cannot fail given &tv_date is a valid address */
310 (void)gettimeofday( &tv_date, NULL );
311 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
320 * This function uses select() and an system date function to wake up at a
321 * precise date. It should be used for process synchronization. If current date
322 * is posterior to wished date, the function returns immediately.
323 * \param date The date to wake up at
325 void mwait( mtime_t date )
327 /* If the deadline is already elapsed, or within the clock precision,
328 * do not even bother the system timer. */
331 #if defined (HAVE_CLOCK_NANOSLEEP)
332 lldiv_t d = lldiv( date, 1000000 );
333 struct timespec ts = { d.quot, d.rem * 1000 };
336 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
340 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
341 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
345 mtime_t delay = date - mdate();
353 * More precise sleep()
355 * Portable usleep() function.
356 * \param delay the amount of time to sleep
358 void msleep( mtime_t delay )
360 #if defined( HAVE_CLOCK_NANOSLEEP )
361 lldiv_t d = lldiv( delay, 1000000 );
362 struct timespec ts = { d.quot, d.rem * 1000 };
365 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
368 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
369 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
372 #elif defined( HAVE_KERNEL_OS_H )
375 #elif defined( WIN32 ) || defined( UNDER_CE )
376 Sleep( (DWORD) (delay / 1000) );
378 #elif defined( HAVE_NANOSLEEP )
379 struct timespec ts_delay;
381 ts_delay.tv_sec = delay / 1000000;
382 ts_delay.tv_nsec = (delay % 1000000) * 1000;
384 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
387 struct timeval tv_delay;
389 tv_delay.tv_sec = delay / 1000000;
390 tv_delay.tv_usec = delay % 1000000;
392 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
393 * or clock_nanosleep() if this is an issue. */
394 select( 0, NULL, NULL, NULL, &tv_delay );
399 * Date management (internal and external)
403 * Initialize a date_t.
405 * \param date to initialize
406 * \param divider (sample rate) numerator
407 * \param divider (sample rate) denominator
410 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
413 p_date->i_divider_num = i_divider_n;
414 p_date->i_divider_den = i_divider_d;
415 p_date->i_remainder = 0;
421 * \param date to change
422 * \param divider (sample rate) numerator
423 * \param divider (sample rate) denominator
426 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
428 p_date->i_divider_num = i_divider_n;
429 p_date->i_divider_den = i_divider_d;
433 * Set the date value of a date_t.
438 void date_Set( date_t *p_date, mtime_t i_new_date )
440 p_date->date = i_new_date;
441 p_date->i_remainder = 0;
445 * Get the date of a date_t
450 mtime_t date_Get( const date_t *p_date )
456 * Move forwards or backwards the date of a date_t.
458 * \param date to move
459 * \param difference value
461 void date_Move( date_t *p_date, mtime_t i_difference )
463 p_date->date += i_difference;
467 * Increment the date and return the result, taking into account
470 * \param date to increment
471 * \param incrementation in number of samples
474 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
476 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
477 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
478 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
480 if( p_date->i_remainder >= p_date->i_divider_num )
482 /* This is Bresenham algorithm. */
483 p_date->date += p_date->i_divider_den;
484 p_date->i_remainder -= p_date->i_divider_num;
490 #ifndef HAVE_GETTIMEOFDAY
495 * Number of micro-seconds between the beginning of the Windows epoch
496 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
498 * This assumes all Win32 compilers have 64-bit support.
500 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
501 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
503 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
506 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
508 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
510 res |= ft->dwLowDateTime;
511 res /= 10; /* from 100 nano-sec periods to usec */
512 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
516 static int gettimeofday (struct timeval *tv, void *tz )
524 GetSystemTimeAsFileTime (&ft);
525 tim = filetime_to_unix_epoch (&ft);
526 tv->tv_sec = (long) (tim / 1000000L);
527 tv->tv_usec = (long) (tim % 1000000L);
536 * @return NTP 64-bits timestamp in host byte order.
538 uint64_t NTPtime64 (void)
541 #if defined (CLOCK_REALTIME)
542 clock_gettime (CLOCK_REALTIME, &ts);
546 gettimeofday (&tv, NULL);
547 ts.tv_sec = tv.tv_sec;
548 ts.tv_nsec = tv.tv_usec * 1000;
552 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
553 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
557 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
558 * No leap seconds during that period since they were not invented yet.
560 assert (t < 0x100000000);
561 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;