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(HAVE_STRUCT_TIMESPEC)
67 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
68 int nanosleep(struct timespec *, struct timespec *);
71 #if !defined (_POSIX_CLOCK_SELECTION)
72 # define _POSIX_CLOCK_SELECTION (-1)
75 # if (_POSIX_CLOCK_SELECTION < 0)
77 * We cannot use the monotonic clock is clock selection is not available,
78 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
79 * stick to the realtime clock. Nevermind it screws everything when ntpdate
80 * warps the wall clock.
82 # undef CLOCK_MONOTONIC
83 # define CLOCK_MONOTONIC CLOCK_REALTIME
84 #elif !defined (HAVE_CLOCK_NANOSLEEP)
85 /* Clock selection without clock in the first place, I don't think so. */
86 # error We have quite a situation here! Fix me if it ever happens.
90 * Return a date in a readable format
92 * This function converts a mtime date into a string.
93 * psz_buffer should be a buffer long enough to store the formatted
95 * \param date to be converted
96 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
97 * \return psz_buffer is returned so this can be used as printf parameter.
99 char *mstrtime( char *psz_buffer, mtime_t date )
101 static const mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
103 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
104 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
105 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
106 (int) (date / (ll1000 * ll1000) % ll60),
107 (int) (date / ll1000 % ll1000),
108 (int) (date % ll1000) );
109 return( psz_buffer );
113 * Convert seconds to a time in the format h:mm:ss.
115 * This function is provided for any interface function which need to print a
116 * time string in the format h:mm:ss
118 * \param secs the date to be converted
119 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
120 * \return psz_buffer is returned so this can be used as printf parameter.
122 char *secstotimestr( char *psz_buffer, int i_seconds )
125 i_mins = i_seconds / 60;
126 i_hours = i_mins / 60 ;
129 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
132 (int) (i_seconds % 60) );
136 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
138 (int) (i_seconds % 60) );
140 return( psz_buffer );
143 #if defined (HAVE_CLOCK_NANOSLEEP)
144 static unsigned prec = 0;
146 static void mprec_once( void )
149 if( clock_getres( CLOCK_MONOTONIC, &ts ))
150 clock_getres( CLOCK_REALTIME, &ts );
152 prec = ts.tv_nsec / 1000;
157 * Return a value that is no bigger than the clock precision
160 static inline unsigned mprec( void )
162 #if defined (HAVE_CLOCK_NANOSLEEP)
163 static pthread_once_t once = PTHREAD_ONCE_INIT;
164 pthread_once( &once, mprec_once );
172 * Return high precision date
174 * Use a 1 MHz clock when possible, or 1 kHz
176 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
178 mtime_t mdate( void )
182 #if defined (HAVE_CLOCK_NANOSLEEP)
185 /* Try to use POSIX monotonic clock if available */
186 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
187 /* Run-time fallback to real-time clock (always available) */
188 (void)clock_gettime( CLOCK_REALTIME, &ts );
190 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
191 + (mtime_t)(ts.tv_nsec / 1000);
193 #elif defined( HAVE_KERNEL_OS_H )
194 res = real_time_clock_usecs();
196 #elif defined( WIN32 ) || defined( UNDER_CE )
197 /* We don't need the real date, just the value of a high precision timer */
198 static mtime_t freq = INT64_C(-1);
200 if( freq == INT64_C(-1) )
202 /* Extract from the Tcl source code:
203 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
205 * Some hardware abstraction layers use the CPU clock
206 * in place of the real-time clock as a performance counter
207 * reference. This results in:
208 * - inconsistent results among the processors on
209 * multi-processor systems.
210 * - unpredictable changes in performance counter frequency
211 * on "gearshift" processors such as Transmeta and
213 * There seems to be no way to test whether the performance
214 * counter is reliable, but a useful heuristic is that
215 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
216 * derived from a colorburst crystal and is therefore
217 * the RTC rather than the TSC. If it's anything else, we
218 * presume that the performance counter is unreliable.
222 freq = ( QueryPerformanceFrequency( &buf ) &&
223 (buf.QuadPart == INT64_C(1193182) || buf.QuadPart == INT64_C(3579545) ) )
227 /* on windows 2000, XP and Vista detect if there are two
228 cores there - that makes QueryPerformanceFrequency in
229 any case not trustable?
230 (may also be true, for single cores with adaptive
231 CPU frequency and active power management?)
233 HINSTANCE h_Kernel32 = LoadLibrary(_T("kernel32.dll"));
236 void WINAPI (*pf_GetSystemInfo)(LPSYSTEM_INFO);
237 pf_GetSystemInfo = (void WINAPI (*)(LPSYSTEM_INFO))
238 GetProcAddress(h_Kernel32, _T("GetSystemInfo"));
241 SYSTEM_INFO system_info;
242 pf_GetSystemInfo(&system_info);
243 if(system_info.dwNumberOfProcessors > 1)
246 FreeLibrary(h_Kernel32);
253 LARGE_INTEGER counter;
254 QueryPerformanceCounter (&counter);
256 /* Convert to from (1/freq) to microsecond resolution */
257 /* We need to split the division to avoid 63-bits overflow */
258 lldiv_t d = lldiv (counter.QuadPart, freq);
260 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
264 /* Fallback on timeGetTime() which has a millisecond resolution
265 * (actually, best case is about 5 ms resolution)
266 * timeGetTime() only returns a DWORD thus will wrap after
267 * about 49.7 days so we try to detect the wrapping. */
269 static CRITICAL_SECTION date_lock;
270 static mtime_t i_previous_time = INT64_C(-1);
271 static int i_wrap_counts = -1;
273 if( i_wrap_counts == -1 )
277 i_previous_time = INT64_C(1000) * timeGetTime();
279 i_previous_time = INT64_C(1000) * GetTickCount();
281 InitializeCriticalSection( &date_lock );
285 EnterCriticalSection( &date_lock );
287 res = INT64_C(1000) *
288 (i_wrap_counts * INT64_C(0x100000000) + timeGetTime());
290 res = INT64_C(1000) *
291 (i_wrap_counts * INT64_C(0x100000000) + GetTickCount());
293 if( i_previous_time > res )
295 /* Counter wrapped */
297 res += INT64_C(0x100000000) * 1000;
299 i_previous_time = res;
300 LeaveCriticalSection( &date_lock );
303 struct timeval tv_date;
305 /* gettimeofday() cannot fail given &tv_date is a valid address */
306 (void)gettimeofday( &tv_date, NULL );
307 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
317 * This function uses select() and an system date function to wake up at a
318 * precise date. It should be used for process synchronization. If current date
319 * is posterior to wished date, the function returns immediately.
320 * \param date The date to wake up at
322 void mwait( mtime_t date )
324 /* If the deadline is already elapsed, or within the clock precision,
325 * do not even bother the system timer. */
328 #if defined (HAVE_CLOCK_NANOSLEEP)
329 lldiv_t d = lldiv( date, 1000000 );
330 struct timespec ts = { d.quot, d.rem * 1000 };
333 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
337 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
338 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
341 #elif defined (WIN32)
344 while( (i_total = (date - mdate())) > 0 )
346 const mtime_t i_sleep = i_total / 1000;
347 DWORD i_delay = (i_sleep > 0x7fffffff) ? 0x7fffffff : i_sleep;
349 SleepEx( i_delay, TRUE );
354 mtime_t delay = date - mdate();
362 #include "libvlc.h" /* vlc_backtrace() */
366 * Portable usleep(). Cancellation point.
368 * \param delay the amount of time to sleep
370 void msleep( mtime_t delay )
372 #if defined( HAVE_CLOCK_NANOSLEEP )
373 lldiv_t d = lldiv( delay, 1000000 );
374 struct timespec ts = { d.quot, d.rem * 1000 };
377 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
380 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
381 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
384 #elif defined( HAVE_KERNEL_OS_H )
387 #elif defined( WIN32 ) || defined( UNDER_CE )
388 mwait (mdate () + delay);
390 #elif defined( HAVE_NANOSLEEP )
391 struct timespec ts_delay;
393 ts_delay.tv_sec = delay / 1000000;
394 ts_delay.tv_nsec = (delay % 1000000) * 1000;
396 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
399 struct timeval tv_delay;
401 tv_delay.tv_sec = delay / 1000000;
402 tv_delay.tv_usec = delay % 1000000;
404 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
405 * or clock_nanosleep() if this is an issue. */
406 select( 0, NULL, NULL, NULL, &tv_delay );
411 * Date management (internal and external)
415 * Initialize a date_t.
417 * \param date to initialize
418 * \param divider (sample rate) numerator
419 * \param divider (sample rate) denominator
422 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
425 p_date->i_divider_num = i_divider_n;
426 p_date->i_divider_den = i_divider_d;
427 p_date->i_remainder = 0;
433 * \param date to change
434 * \param divider (sample rate) numerator
435 * \param divider (sample rate) denominator
438 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
440 /* change time scale of remainder */
441 p_date->i_remainder = p_date->i_remainder * i_divider_n / p_date->i_divider_num;
442 p_date->i_divider_num = i_divider_n;
443 p_date->i_divider_den = i_divider_d;
447 * Set the date value of a date_t.
452 void date_Set( date_t *p_date, mtime_t i_new_date )
454 p_date->date = i_new_date;
455 p_date->i_remainder = 0;
459 * Get the date of a date_t
464 mtime_t date_Get( const date_t *p_date )
470 * Move forwards or backwards the date of a date_t.
472 * \param date to move
473 * \param difference value
475 void date_Move( date_t *p_date, mtime_t i_difference )
477 p_date->date += i_difference;
481 * Increment the date and return the result, taking into account
484 * \param date to increment
485 * \param incrementation in number of samples
488 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
490 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000 * p_date->i_divider_den;
491 p_date->date += i_dividend / p_date->i_divider_num;
492 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
494 if( p_date->i_remainder >= p_date->i_divider_num )
496 /* This is Bresenham algorithm. */
497 assert( p_date->i_remainder < 2*p_date->i_divider_num);
499 p_date->i_remainder -= p_date->i_divider_num;
505 #ifndef HAVE_GETTIMEOFDAY
510 * Number of micro-seconds between the beginning of the Windows epoch
511 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
513 * This assumes all Win32 compilers have 64-bit support.
515 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
516 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
518 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
521 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
523 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
525 res |= ft->dwLowDateTime;
526 res /= 10; /* from 100 nano-sec periods to usec */
527 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
531 static int gettimeofday (struct timeval *tv, void *tz )
539 GetSystemTimeAsFileTime (&ft);
540 tim = filetime_to_unix_epoch (&ft);
541 tv->tv_sec = (long) (tim / 1000000L);
542 tv->tv_usec = (long) (tim % 1000000L);
551 * @return NTP 64-bits timestamp in host byte order.
553 uint64_t NTPtime64 (void)
556 #if defined (CLOCK_REALTIME)
557 clock_gettime (CLOCK_REALTIME, &ts);
561 gettimeofday (&tv, NULL);
562 ts.tv_sec = tv.tv_sec;
563 ts.tv_nsec = tv.tv_usec * 1000;
567 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
568 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
572 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
573 * No leap seconds during that period since they were not invented yet.
575 assert (t < 0x100000000);
576 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;