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 # include <unistd.h> /* select() */
42 #ifdef HAVE_KERNEL_OS_H
43 # include <kernel/OS.h>
46 #if defined( WIN32 ) || defined( UNDER_CE )
49 #if defined(HAVE_SYS_TIME_H)
50 # include <sys/time.h>
53 #if !defined(HAVE_STRUCT_TIMESPEC)
61 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
62 int nanosleep(struct timespec *, struct timespec *);
65 #if !defined (_POSIX_CLOCK_SELECTION)
66 # define _POSIX_CLOCK_SELECTION (-1)
69 # if (_POSIX_CLOCK_SELECTION < 0)
71 * We cannot use the monotonic clock is clock selection is not available,
72 * as it would screw vlc_cond_timedwait() completely. Instead, we have to
73 * stick to the realtime clock. Nevermind it screws everything when ntpdate
74 * warps the wall clock.
76 # undef CLOCK_MONOTONIC
77 # define CLOCK_MONOTONIC CLOCK_REALTIME
78 #elif !defined (HAVE_CLOCK_NANOSLEEP)
79 /* Clock selection without clock in the first place, I don't think so. */
80 # error We have quite a situation here! Fix me if it ever happens.
84 * Return a date in a readable format
86 * This function converts a mtime date into a string.
87 * psz_buffer should be a buffer long enough to store the formatted
89 * \param date to be converted
90 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
91 * \return psz_buffer is returned so this can be used as printf parameter.
93 char *mstrtime( char *psz_buffer, mtime_t date )
95 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
97 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
98 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
99 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
100 (int) (date / (ll1000 * ll1000) % ll60),
101 (int) (date / ll1000 % ll1000),
102 (int) (date % ll1000) );
103 return( psz_buffer );
107 * Convert seconds to a time in the format h:mm:ss.
109 * This function is provided for any interface function which need to print a
110 * time string in the format h:mm:ss
112 * \param secs the date to be converted
113 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
114 * \return psz_buffer is returned so this can be used as printf parameter.
116 char *secstotimestr( char *psz_buffer, int i_seconds )
119 i_mins = i_seconds / 60;
120 i_hours = i_mins / 60 ;
123 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
126 (int) (i_seconds % 60) );
130 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%2.2d:%2.2d",
132 (int) (i_seconds % 60) );
134 return( psz_buffer );
138 * Return a value that is no bigger than the clock precision
141 static inline unsigned mprec( void )
143 #if defined (HAVE_CLOCK_NANOSLEEP)
145 if( clock_getres( CLOCK_MONOTONIC, &ts ))
146 clock_getres( CLOCK_REALTIME, &ts );
148 return ts.tv_nsec / 1000;
153 static unsigned prec = 0;
154 static volatile mtime_t cached_time = 0;
157 * Return high precision date
159 * Use a 1 MHz clock when possible, or 1 kHz
161 * Beware ! It doesn't reflect the actual date (since epoch), but can be the machine's uptime or anything (when monotonic clock is used)
163 mtime_t mdate( void )
167 #if defined (HAVE_CLOCK_NANOSLEEP)
170 /* Try to use POSIX monotonic clock if available */
171 if( clock_gettime( CLOCK_MONOTONIC, &ts ) == EINVAL )
172 /* Run-time fallback to real-time clock (always available) */
173 (void)clock_gettime( CLOCK_REALTIME, &ts );
175 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
176 + (mtime_t)(ts.tv_nsec / 1000);
178 #elif defined( HAVE_KERNEL_OS_H )
179 res = real_time_clock_usecs();
181 #elif defined( WIN32 ) || defined( UNDER_CE )
182 /* We don't need the real date, just the value of a high precision timer */
183 static mtime_t freq = I64C(-1);
185 if( freq == I64C(-1) )
187 /* Extract from the Tcl source code:
188 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
190 * Some hardware abstraction layers use the CPU clock
191 * in place of the real-time clock as a performance counter
192 * reference. This results in:
193 * - inconsistent results among the processors on
194 * multi-processor systems.
195 * - unpredictable changes in performance counter frequency
196 * on "gearshift" processors such as Transmeta and
198 * There seems to be no way to test whether the performance
199 * counter is reliable, but a useful heuristic is that
200 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
201 * derived from a colorburst crystal and is therefore
202 * the RTC rather than the TSC. If it's anything else, we
203 * presume that the performance counter is unreliable.
207 freq = ( QueryPerformanceFrequency( &buf ) &&
208 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
214 LARGE_INTEGER counter;
215 QueryPerformanceCounter (&counter);
217 /* Convert to from (1/freq) to microsecond resolution */
218 /* We need to split the division to avoid 63-bits overflow */
219 lldiv_t d = lldiv (counter.QuadPart, freq);
221 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
225 /* Fallback on GetTickCount() which has a milisecond resolution
226 * (actually, best case is about 10 ms resolution)
227 * GetTickCount() only returns a DWORD thus will wrap after
228 * about 49.7 days so we try to detect the wrapping. */
230 static CRITICAL_SECTION date_lock;
231 static mtime_t i_previous_time = I64C(-1);
232 static int i_wrap_counts = -1;
234 if( i_wrap_counts == -1 )
237 i_previous_time = I64C(1000) * GetTickCount();
238 InitializeCriticalSection( &date_lock );
242 EnterCriticalSection( &date_lock );
244 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
245 if( i_previous_time > res )
247 /* Counter wrapped */
249 res += I64C(0x100000000) * 1000;
251 i_previous_time = res;
252 LeaveCriticalSection( &date_lock );
255 struct timeval tv_date;
257 /* gettimeofday() cannot fail given &tv_date is a valid address */
258 (void)gettimeofday( &tv_date, NULL );
259 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
262 return cached_time = res;
268 * This function uses select() and an system date function to wake up at a
269 * precise date. It should be used for process synchronization. If current date
270 * is posterior to wished date, the function returns immediately.
271 * \param date The date to wake up at
273 void mwait( mtime_t date )
278 /* If the deadline is already elapsed, or within the clock precision,
279 * do not even bother the clock. */
280 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
283 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
284 lldiv_t d = lldiv( date, 1000000 );
285 struct timespec ts = { d.quot, d.rem * 1000 };
288 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts,
292 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
293 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL ) == EINTR );
297 mtime_t delay = date - mdate();
305 * More precise sleep()
307 * Portable usleep() function.
308 * \param delay the amount of time to sleep
310 void msleep( mtime_t delay )
312 mtime_t earlier = cached_time;
314 #if defined( HAVE_CLOCK_NANOSLEEP )
315 lldiv_t d = lldiv( delay, 1000000 );
316 struct timespec ts = { d.quot, d.rem * 1000 };
319 while( ( val = clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, &ts ) ) == EINTR );
322 ts.tv_sec = d.quot; ts.tv_nsec = d.rem * 1000;
323 while( clock_nanosleep( CLOCK_REALTIME, 0, &ts, &ts ) == EINTR );
326 #elif defined( HAVE_KERNEL_OS_H )
329 #elif defined( WIN32 ) || defined( UNDER_CE )
330 Sleep( (int) (delay / 1000) );
332 #elif defined( HAVE_NANOSLEEP )
333 struct timespec ts_delay;
335 ts_delay.tv_sec = delay / 1000000;
336 ts_delay.tv_nsec = (delay % 1000000) * 1000;
338 while( nanosleep( &ts_delay, &ts_delay ) && ( errno == EINTR ) );
341 struct timeval tv_delay;
343 tv_delay.tv_sec = delay / 1000000;
344 tv_delay.tv_usec = delay % 1000000;
346 /* If a signal is caught, you are screwed. Update your OS to nanosleep()
347 * or clock_nanosleep() if this is an issue. */
348 select( 0, NULL, NULL, NULL, &tv_delay );
352 if( cached_time < earlier )
353 cached_time = earlier;
357 * Date management (internal and external)
361 * Initialize a date_t.
363 * \param date to initialize
364 * \param divider (sample rate) numerator
365 * \param divider (sample rate) denominator
368 void date_Init( 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;
373 p_date->i_remainder = 0;
379 * \param date to change
380 * \param divider (sample rate) numerator
381 * \param divider (sample rate) denominator
384 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
386 p_date->i_divider_num = i_divider_n;
387 p_date->i_divider_den = i_divider_d;
391 * Set the date value of a date_t.
396 void date_Set( date_t *p_date, mtime_t i_new_date )
398 p_date->date = i_new_date;
399 p_date->i_remainder = 0;
403 * Get the date of a date_t
408 mtime_t date_Get( const date_t *p_date )
414 * Move forwards or backwards the date of a date_t.
416 * \param date to move
417 * \param difference value
419 void date_Move( date_t *p_date, mtime_t i_difference )
421 p_date->date += i_difference;
425 * Increment the date and return the result, taking into account
428 * \param date to increment
429 * \param incrementation in number of samples
432 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
434 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
435 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
436 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
438 if( p_date->i_remainder >= p_date->i_divider_num )
440 /* This is Bresenham algorithm. */
441 p_date->date += p_date->i_divider_den;
442 p_date->i_remainder -= p_date->i_divider_num;
448 #ifndef HAVE_GETTIMEOFDAY
453 * Number of micro-seconds between the beginning of the Windows epoch
454 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
456 * This assumes all Win32 compilers have 64-bit support.
458 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
459 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
461 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
464 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
466 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
468 res |= ft->dwLowDateTime;
469 res /= 10; /* from 100 nano-sec periods to usec */
470 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
474 static int gettimeofday (struct timeval *tv, void *tz )
482 GetSystemTimeAsFileTime (&ft);
483 tim = filetime_to_unix_epoch (&ft);
484 tv->tv_sec = (long) (tim / 1000000L);
485 tv->tv_usec = (long) (tim % 1000000L);
494 * @return NTP 64-bits timestamp in host byte order.
496 uint64_t NTPtime64 (void)
499 #if defined (CLOCK_REALTIME)
500 clock_gettime (CLOCK_REALTIME, &ts);
504 gettimeofday (&tv, NULL);
505 ts.tv_sec = tv.tv_sec;
506 ts.tv_nsec = tv.tv_usec * 1000;
510 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
511 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
515 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
516 * No leap seconds during that period since they were not invented yet.
518 assert (t < 0x100000000);
519 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;