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 #if !defined (_POSIX_CLOCK_SELECTION)
71 # define _POSIX_CLOCK_SELECTION (-1)
74 # if (_POSIX_CLOCK_SELECTION < 0)
76 * We cannot use the monotonic clock is clock selection is not available,
77 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
78 * stick to the realtime clock. Nevermind it screws everything when ntpdate
79 * warps the wall clock.
81 # undef CLOCK_MONOTONIC
82 # define CLOCK_MONOTONIC CLOCK_REALTIME
83 #elif !defined (HAVE_CLOCK_NANOSLEEP)
84 /* Clock selection without clock in the first place, I don't think so. */
85 # error We have quite a situation here! Fix me if it ever happens.
89 * Return a date in a readable format
91 * This function converts a mtime date into a string.
92 * psz_buffer should be a buffer long enough to store the formatted
94 * \param date to be converted
95 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
96 * \return psz_buffer is returned so this can be used as printf parameter.
98 char *mstrtime( char *psz_buffer, mtime_t date )
100 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
102 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
103 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
104 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
105 (int) (date / (ll1000 * ll1000) % ll60),
106 (int) (date / ll1000 % ll1000),
107 (int) (date % ll1000) );
108 return( psz_buffer );
112 * Convert seconds to a time in the format h:mm:ss.
114 * This function is provided for any interface function which need to print a
115 * time string in the format h:mm:ss
117 * \param secs the date to be converted
118 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
119 * \return psz_buffer is returned so this can be used as printf parameter.
121 char *secstotimestr( char *psz_buffer, int i_seconds )
124 i_mins = i_seconds / 60;
125 i_hours = i_mins / 60 ;
128 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
131 (int) (i_seconds % 60) );
135 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
137 (int) (i_seconds % 60) );
139 return( psz_buffer );
143 * Return a value that is no bigger than the clock precision
146 static inline unsigned mprec( void )
148 #if defined (HAVE_CLOCK_NANOSLEEP)
150 if( clock_getres( CLOCK_MONOTONIC, &ts ))
151 clock_getres( CLOCK_REALTIME, &ts );
153 return ts.tv_nsec / 1000;
158 static unsigned prec = 0;
159 static volatile mtime_t cached_time = 0;
162 * Return high precision date
164 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
165 * ftime() function (1 kHz resolution).
167 mtime_t mdate( void )
171 #if defined (HAVE_CLOCK_NANOSLEEP)
174 /* Try to use POSIX monotonic clock if available */
175 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
176 /* Run-time fallback to real-time clock (always available) */
177 (void)clock_gettime( CLOCK_REALTIME, &ts );
179 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
180 + (mtime_t)(ts.tv_nsec / 1000);
182 #elif defined( HAVE_KERNEL_OS_H )
183 res = real_time_clock_usecs();
185 #elif defined( WIN32 ) || defined( UNDER_CE )
186 /* We don't need the real date, just the value of a high precision timer */
187 static mtime_t freq = I64C(-1);
189 if( freq == I64C(-1) )
191 /* Extract from the Tcl source code:
192 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
194 * Some hardware abstraction layers use the CPU clock
195 * in place of the real-time clock as a performance counter
196 * reference. This results in:
197 * - inconsistent results among the processors on
198 * multi-processor systems.
199 * - unpredictable changes in performance counter frequency
200 * on "gearshift" processors such as Transmeta and
202 * There seems to be no way to test whether the performance
203 * counter is reliable, but a useful heuristic is that
204 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
205 * derived from a colorburst crystal and is therefore
206 * the RTC rather than the TSC. If it's anything else, we
207 * presume that the performance counter is unreliable.
211 freq = ( QueryPerformanceFrequency( &buf ) &&
212 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
218 LARGE_INTEGER counter;
219 QueryPerformanceCounter (&counter);
221 /* Convert to from (1/freq) to microsecond resolution */
222 /* We need to split the division to avoid 63-bits overflow */
223 lldiv_t d = lldiv (counter.QuadPart, freq);
225 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
229 /* Fallback on GetTickCount() which has a milisecond resolution
230 * (actually, best case is about 10 ms resolution)
231 * GetTickCount() only returns a DWORD thus will wrap after
232 * about 49.7 days so we try to detect the wrapping. */
234 static CRITICAL_SECTION date_lock;
235 static mtime_t i_previous_time = I64C(-1);
236 static int i_wrap_counts = -1;
238 if( i_wrap_counts == -1 )
241 i_previous_time = I64C(1000) * GetTickCount();
242 InitializeCriticalSection( &date_lock );
246 EnterCriticalSection( &date_lock );
248 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
249 if( i_previous_time > res )
251 /* Counter wrapped */
253 res += I64C(0x100000000) * 1000;
255 i_previous_time = res;
256 LeaveCriticalSection( &date_lock );
259 struct timeval tv_date;
261 /* gettimeofday() cannot fail given &tv_date is a valid address */
262 (void)gettimeofday( &tv_date, NULL );
263 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
266 return cached_time = res;
272 * This function uses select() and an system date function to wake up at a
273 * precise date. It should be used for process synchronization. If current date
274 * is posterior to wished date, the function returns immediately.
275 * \param date The date to wake up at
277 void mwait( mtime_t date )
282 /* If the deadline is already elapsed, or within the clock precision,
283 * do not even bother the clock. */
284 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
287 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
288 lldiv_t d = lldiv( date, 1000000 );
289 struct timespec ts = { d.quot, d.rem * 1000 };
292 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
296 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
297 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
301 mtime_t delay = date - mdate();
309 * More precise sleep()
311 * Portable usleep() function.
312 * \param delay the amount of time to sleep
314 void msleep( mtime_t delay )
316 mtime_t earlier = cached_time;
318 #if defined( HAVE_CLOCK_NANOSLEEP )
319 lldiv_t d = lldiv( delay, 1000000 );
320 struct timespec ts = { d.quot, d.rem * 1000 };
323 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
326 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
327 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
330 #elif defined( HAVE_KERNEL_OS_H )
333 #elif defined( PTH_INIT_IN_PTH_H )
336 #elif defined( ST_INIT_IN_ST_H )
339 #elif defined( WIN32 ) || defined( UNDER_CE )
340 Sleep( (int) (delay / 1000) );
342 #elif defined( HAVE_NANOSLEEP )
343 struct timespec ts_delay;
345 ts_delay.tv_sec = delay / 1000000;
346 ts_delay.tv_nsec = (delay % 1000000) * 1000;
348 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
351 struct timeval tv_delay;
353 tv_delay.tv_sec = delay / 1000000;
354 tv_delay.tv_usec = delay % 1000000;
356 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
357 * or clock_nanosleep() if this is an issue. */
358 select( 0, NULL, NULL, NULL, &tv_delay );
362 if( cached_time < earlier )
363 cached_time = earlier;
367 * Date management (internal and external)
371 * Initialize a date_t.
373 * \param date to initialize
374 * \param divider (sample rate) numerator
375 * \param divider (sample rate) denominator
378 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
381 p_date->i_divider_num = i_divider_n;
382 p_date->i_divider_den = i_divider_d;
383 p_date->i_remainder = 0;
389 * \param date to change
390 * \param divider (sample rate) numerator
391 * \param divider (sample rate) denominator
394 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
396 p_date->i_divider_num = i_divider_n;
397 p_date->i_divider_den = i_divider_d;
401 * Set the date value of a date_t.
406 void date_Set( date_t *p_date, mtime_t i_new_date )
408 p_date->date = i_new_date;
409 p_date->i_remainder = 0;
413 * Get the date of a date_t
418 mtime_t date_Get( const date_t *p_date )
424 * Move forwards or backwards the date of a date_t.
426 * \param date to move
427 * \param difference value
429 void date_Move( date_t *p_date, mtime_t i_difference )
431 p_date->date += i_difference;
435 * Increment the date and return the result, taking into account
438 * \param date to increment
439 * \param incrementation in number of samples
442 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
444 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
445 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
446 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
448 if( p_date->i_remainder >= p_date->i_divider_num )
450 /* This is Bresenham algorithm. */
451 p_date->date += p_date->i_divider_den;
452 p_date->i_remainder -= p_date->i_divider_num;
458 #ifndef HAVE_GETTIMEOFDAY
463 * Number of micro-seconds between the beginning of the Windows epoch
464 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
466 * This assumes all Win32 compilers have 64-bit support.
468 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
469 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
471 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
474 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
476 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
478 res |= ft->dwLowDateTime;
479 res /= 10; /* from 100 nano-sec periods to usec */
480 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
484 static int gettimeofday (struct timeval *tv, void *tz )
492 GetSystemTimeAsFileTime (&ft);
493 tim = filetime_to_unix_epoch (&ft);
494 tv->tv_sec = (long) (tim / 1000000L);
495 tv->tv_usec = (long) (tim % 1000000L);
504 * @return NTP 64-bits timestamp in host byte order.
506 uint64_t NTPtime64 (void)
509 #if defined (CLOCK_REALTIME)
510 clock_gettime (CLOCK_REALTIME, &ts);
514 gettimeofday (&tv, NULL);
515 ts.tv_sec = tv.tv_sec;
516 ts.tv_nsec = tv.tv_usec * 1000;
520 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
521 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
525 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
526 * No leap seconds during that period since they were not invented yet.
528 assert (t < 0x100000000);
529 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;