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 <stdio.h> /* sprintf() */
35 #include <time.h> /* clock_gettime(), clock_nanosleep() */
36 #include <stdlib.h> /* lldiv() */
40 #if defined( PTH_INIT_IN_PTH_H ) /* GNU Pth */
45 # include <unistd.h> /* select() */
48 #ifdef HAVE_KERNEL_OS_H
49 # include <kernel/OS.h>
52 #if defined( WIN32 ) || defined( UNDER_CE )
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 *);
72 * Return a date in a readable format
74 * This function converts a mtime date into a string.
75 * psz_buffer should be a buffer long enough to store the formatted
77 * \param date to be converted
78 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
79 * \return psz_buffer is returned so this can be used as printf parameter.
81 char *mstrtime( char *psz_buffer, mtime_t date )
83 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
85 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
86 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
87 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
88 (int) (date / (ll1000 * ll1000) % ll60),
89 (int) (date / ll1000 % ll1000),
90 (int) (date % ll1000) );
95 * Convert seconds to a time in the format h:mm:ss.
97 * This function is provided for any interface function which need to print a
98 * time string in the format h:mm:ss
100 * \param secs the date to be converted
101 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
102 * \return psz_buffer is returned so this can be used as printf parameter.
104 char *secstotimestr( char *psz_buffer, int i_seconds )
106 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
107 (int) (i_seconds / (60 *60)),
108 (int) ((i_seconds / 60) % 60),
109 (int) (i_seconds % 60) );
110 return( psz_buffer );
114 * Return a value that is no bigger than the clock precision
117 static inline unsigned mprec( void )
119 #if defined (HAVE_CLOCK_NANOSLEEP)
121 if( clock_getres( CLOCK_MONOTONIC, &ts ))
122 clock_getres( CLOCK_REALTIME, &ts );
124 return ts.tv_nsec / 1000;
129 static unsigned prec = 0;
130 static volatile mtime_t cached_time = 0;
133 * Return high precision date
135 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
136 * ftime() function (1 kHz resolution).
138 mtime_t mdate( void )
142 #if defined (HAVE_CLOCK_NANOSLEEP)
145 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
146 /* Try to use POSIX monotonic clock if available */
147 if( clock_gettime( CLOCK_MONOTONIC, &ts ) )
149 /* Run-time fallback to real-time clock (always available) */
150 (void)clock_gettime( CLOCK_REALTIME, &ts );
152 res = ((mtime_t)ts.tv_sec * (mtime_t)1000000)
153 + (mtime_t)(ts.tv_nsec / 1000);
155 #elif defined( HAVE_KERNEL_OS_H )
156 res = real_time_clock_usecs();
158 #elif defined( WIN32 ) || defined( UNDER_CE )
159 /* We don't need the real date, just the value of a high precision timer */
160 static mtime_t freq = I64C(-1);
162 if( freq == I64C(-1) )
164 /* Extract from the Tcl source code:
165 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
167 * Some hardware abstraction layers use the CPU clock
168 * in place of the real-time clock as a performance counter
169 * reference. This results in:
170 * - inconsistent results among the processors on
171 * multi-processor systems.
172 * - unpredictable changes in performance counter frequency
173 * on "gearshift" processors such as Transmeta and
175 * There seems to be no way to test whether the performance
176 * counter is reliable, but a useful heuristic is that
177 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
178 * derived from a colorburst crystal and is therefore
179 * the RTC rather than the TSC. If it's anything else, we
180 * presume that the performance counter is unreliable.
184 freq = ( QueryPerformanceFrequency( &buf ) &&
185 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
191 LARGE_INTEGER counter;
192 QueryPerformanceCounter (&counter);
194 /* Convert to from (1/freq) to microsecond resolution */
195 /* We need to split the division to avoid 63-bits overflow */
196 lldiv_t d = lldiv (counter.QuadPart, freq);
198 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
202 /* Fallback on GetTickCount() which has a milisecond resolution
203 * (actually, best case is about 10 ms resolution)
204 * GetTickCount() only returns a DWORD thus will wrap after
205 * about 49.7 days so we try to detect the wrapping. */
207 static CRITICAL_SECTION date_lock;
208 static mtime_t i_previous_time = I64C(-1);
209 static int i_wrap_counts = -1;
211 if( i_wrap_counts == -1 )
214 i_previous_time = I64C(1000) * GetTickCount();
215 InitializeCriticalSection( &date_lock );
219 EnterCriticalSection( &date_lock );
221 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
222 if( i_previous_time > res )
224 /* Counter wrapped */
226 usec_time += I64C(0x100000000) * 1000;
228 i_previous_time = usec_time;
229 LeaveCriticalSection( &date_lock );
232 struct timeval tv_date;
234 /* gettimeofday() cannot fail given &tv_date is a valid address */
235 (void)gettimeofday( &tv_date, NULL );
236 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
239 return cached_time = res;
245 * This function uses select() and an system date function to wake up at a
246 * precise date. It should be used for process synchronization. If current date
247 * is posterior to wished date, the function returns immediately.
248 * \param date The date to wake up at
250 void mwait( mtime_t date )
255 /* If the deadline is already elapsed, or within the clock precision,
256 * do not even bother the clock. */
257 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
260 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
261 lldiv_t d = lldiv( date, 1000000 );
262 struct timespec ts = { d.quot, d.rem * 1000 };
264 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
265 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
267 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
270 mtime_t delay = date - mdate();
278 * More precise sleep()
280 * Portable usleep() function.
281 * \param delay the amount of time to sleep
283 void msleep( mtime_t delay )
285 mtime_t earlier = cached_time;
287 #if defined( HAVE_CLOCK_NANOSLEEP )
288 lldiv_t d = lldiv( delay, 1000000 );
289 struct timespec ts = { d.quot, d.rem * 1000 };
291 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
292 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
294 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
296 #elif defined( HAVE_KERNEL_OS_H )
299 #elif defined( PTH_INIT_IN_PTH_H )
302 #elif defined( ST_INIT_IN_ST_H )
305 #elif defined( WIN32 ) || defined( UNDER_CE )
306 Sleep( (int) (delay / 1000) );
308 #elif defined( HAVE_NANOSLEEP )
309 struct timespec ts_delay;
311 ts_delay.tv_sec = delay / 1000000;
312 ts_delay.tv_nsec = (delay % 1000000) * 1000;
314 nanosleep( &ts_delay, NULL );
317 struct timeval tv_delay;
319 tv_delay.tv_sec = delay / 1000000;
320 tv_delay.tv_usec = delay % 1000000;
322 /* select() return value should be tested, since several possible errors
323 * can occur. However, they should only happen in very particular occasions
324 * (i.e. when a signal is sent to the thread, or when memory is full), and
326 select( 0, NULL, NULL, NULL, &tv_delay );
330 if( cached_time < earlier )
331 cached_time = earlier;
335 * Date management (internal and external)
339 * Initialize a date_t.
341 * \param date to initialize
342 * \param divider (sample rate) numerator
343 * \param divider (sample rate) denominator
346 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
349 p_date->i_divider_num = i_divider_n;
350 p_date->i_divider_den = i_divider_d;
351 p_date->i_remainder = 0;
357 * \param date to change
358 * \param divider (sample rate) numerator
359 * \param divider (sample rate) denominator
362 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
364 p_date->i_divider_num = i_divider_n;
365 p_date->i_divider_den = i_divider_d;
369 * Set the date value of a date_t.
374 void date_Set( date_t *p_date, mtime_t i_new_date )
376 p_date->date = i_new_date;
377 p_date->i_remainder = 0;
381 * Get the date of a date_t
386 mtime_t date_Get( const date_t *p_date )
392 * Move forwards or backwards the date of a date_t.
394 * \param date to move
395 * \param difference value
397 void date_Move( date_t *p_date, mtime_t i_difference )
399 p_date->date += i_difference;
403 * Increment the date and return the result, taking into account
406 * \param date to increment
407 * \param incrementation in number of samples
410 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
412 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
413 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
414 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
416 if( p_date->i_remainder >= p_date->i_divider_num )
418 /* This is Bresenham algorithm. */
419 p_date->date += p_date->i_divider_den;
420 p_date->i_remainder -= p_date->i_divider_num;
428 * Number of micro-seconds between the beginning of the Windows epoch
429 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
431 * This assumes all Win32 compilers have 64-bit support.
433 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
434 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
436 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
439 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
441 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
443 res |= ft->dwLowDateTime;
444 res /= 10; /* from 100 nano-sec periods to usec */
445 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
449 static int gettimeofday (struct timeval *tv, void *tz )
457 GetSystemTimeAsFileTime (&ft);
458 tim = filetime_to_unix_epoch (&ft);
459 tv->tv_sec = (long) (tim / 1000000L);
460 tv->tv_usec = (long) (tim % 1000000L);
468 * @return NTP 64-bits timestamp in host byte order.
470 uint64_t NTPtime64 (void)
473 #if defined (CLOCK_REALTIME)
474 clock_gettime (CLOCK_REALTIME, &ts);
478 gettimeofday (&tv, NULL);
479 ts.tv_sec = tv.tv_sec;
480 ts.tv_nsec = tv.tv_usec * 1000;
484 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
485 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
489 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
490 * No leap seconds during that period since they were not invented yet.
492 assert (t < 0x100000000);
493 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;