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 );
115 * Return high precision date
117 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
118 * ftime() function (1 kHz resolution).
120 mtime_t mdate( void )
122 #if defined (HAVE_CLOCK_NANOSLEEP)
125 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
126 /* Try to use POSIX monotonic clock if available */
127 if( clock_gettime( CLOCK_MONOTONIC, &ts ) )
129 /* Run-time fallback to real-time clock (always available) */
130 (void)clock_gettime( CLOCK_REALTIME, &ts );
132 return ((mtime_t)ts.tv_sec * (mtime_t)1000000)
133 + (mtime_t)(ts.tv_nsec / 1000);
135 #elif defined( HAVE_KERNEL_OS_H )
136 return( real_time_clock_usecs() );
138 #elif defined( WIN32 ) || defined( UNDER_CE )
139 /* We don't need the real date, just the value of a high precision timer */
140 static mtime_t freq = I64C(-1);
142 if( freq == I64C(-1) )
144 /* Extract from the Tcl source code:
145 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
147 * Some hardware abstraction layers use the CPU clock
148 * in place of the real-time clock as a performance counter
149 * reference. This results in:
150 * - inconsistent results among the processors on
151 * multi-processor systems.
152 * - unpredictable changes in performance counter frequency
153 * on "gearshift" processors such as Transmeta and
155 * There seems to be no way to test whether the performance
156 * counter is reliable, but a useful heuristic is that
157 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
158 * derived from a colorburst crystal and is therefore
159 * the RTC rather than the TSC. If it's anything else, we
160 * presume that the performance counter is unreliable.
164 freq = ( QueryPerformanceFrequency( &buf ) &&
165 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
171 LARGE_INTEGER counter;
172 QueryPerformanceCounter (&counter);
174 /* Convert to from (1/freq) to microsecond resolution */
175 /* We need to split the division to avoid 63-bits overflow */
176 lldiv_t d = lldiv (counter.QuadPart, freq);
178 return (d.quot * 1000000)
179 + ((d.rem * 1000000) / freq);
183 /* Fallback on GetTickCount() which has a milisecond resolution
184 * (actually, best case is about 10 ms resolution)
185 * GetTickCount() only returns a DWORD thus will wrap after
186 * about 49.7 days so we try to detect the wrapping. */
188 static CRITICAL_SECTION date_lock;
189 static mtime_t i_previous_time = I64C(-1);
190 static int i_wrap_counts = -1;
193 if( i_wrap_counts == -1 )
196 i_previous_time = I64C(1000) * GetTickCount();
197 InitializeCriticalSection( &date_lock );
201 EnterCriticalSection( &date_lock );
202 usec_time = I64C(1000) *
203 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
204 if( i_previous_time > usec_time )
206 /* Counter wrapped */
208 usec_time += I64C(0x100000000) * 1000;
210 i_previous_time = usec_time;
211 LeaveCriticalSection( &date_lock );
216 struct timeval tv_date;
218 /* gettimeofday() cannot fail given &tv_date is a valid address */
219 (void)gettimeofday( &tv_date, NULL );
220 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
227 * This function uses select() and an system date function to wake up at a
228 * precise date. It should be used for process synchronization. If current date
229 * is posterior to wished date, the function returns immediately.
230 * \param date The date to wake up at
232 void mwait( mtime_t date )
234 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
235 lldiv_t d = lldiv( date, 1000000 );
236 struct timespec ts = { d.quot, d.rem * 1000 };
238 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
239 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
241 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
244 mtime_t delay = date - mdate();
252 * More precise sleep()
254 * Portable usleep() function.
255 * \param delay the amount of time to sleep
257 void msleep( mtime_t delay )
259 #if defined( HAVE_CLOCK_NANOSLEEP )
260 lldiv_t d = lldiv( delay, 1000000 );
261 struct timespec ts = { d.quot, d.rem * 1000 };
263 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
264 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
266 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
268 #elif defined( HAVE_KERNEL_OS_H )
271 #elif defined( PTH_INIT_IN_PTH_H )
274 #elif defined( ST_INIT_IN_ST_H )
277 #elif defined( WIN32 ) || defined( UNDER_CE )
278 Sleep( (int) (delay / 1000) );
280 #elif defined( HAVE_NANOSLEEP )
281 struct timespec ts_delay;
283 ts_delay.tv_sec = delay / 1000000;
284 ts_delay.tv_nsec = (delay % 1000000) * 1000;
286 nanosleep( &ts_delay, NULL );
289 struct timeval tv_delay;
291 tv_delay.tv_sec = delay / 1000000;
292 tv_delay.tv_usec = delay % 1000000;
294 /* select() return value should be tested, since several possible errors
295 * can occur. However, they should only happen in very particular occasions
296 * (i.e. when a signal is sent to the thread, or when memory is full), and
298 select( 0, NULL, NULL, NULL, &tv_delay );
303 * Date management (internal and external)
307 * Initialize a date_t.
309 * \param date to initialize
310 * \param divider (sample rate) numerator
311 * \param divider (sample rate) denominator
314 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
317 p_date->i_divider_num = i_divider_n;
318 p_date->i_divider_den = i_divider_d;
319 p_date->i_remainder = 0;
325 * \param date to change
326 * \param divider (sample rate) numerator
327 * \param divider (sample rate) denominator
330 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
332 p_date->i_divider_num = i_divider_n;
333 p_date->i_divider_den = i_divider_d;
337 * Set the date value of a date_t.
342 void date_Set( date_t *p_date, mtime_t i_new_date )
344 p_date->date = i_new_date;
345 p_date->i_remainder = 0;
349 * Get the date of a date_t
354 mtime_t date_Get( const date_t *p_date )
360 * Move forwards or backwards the date of a date_t.
362 * \param date to move
363 * \param difference value
365 void date_Move( date_t *p_date, mtime_t i_difference )
367 p_date->date += i_difference;
371 * Increment the date and return the result, taking into account
374 * \param date to increment
375 * \param incrementation in number of samples
378 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
380 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
381 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
382 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
384 if( p_date->i_remainder >= p_date->i_divider_num )
386 /* This is Bresenham algorithm. */
387 p_date->date += p_date->i_divider_den;
388 p_date->i_remainder -= p_date->i_divider_num;
396 * Number of micro-seconds between the beginning of the Windows epoch
397 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
399 * This assumes all Win32 compilers have 64-bit support.
401 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
402 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
404 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
407 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
409 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
411 res |= ft->dwLowDateTime;
412 res /= 10; /* from 100 nano-sec periods to usec */
413 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
417 static int gettimeofday (struct timeval *tv, void *tz )
425 GetSystemTimeAsFileTime (&ft);
426 tim = filetime_to_unix_epoch (&ft);
427 tv->tv_sec = (long) (tim / 1000000L);
428 tv->tv_usec = (long) (tim % 1000000L);
436 * @return NTP 64-bits timestamp in host byte order.
438 uint64_t NTPtime64 (void)
441 #if defined (CLOCK_REALTIME)
442 clock_gettime (CLOCK_REALTIME, &ts);
446 gettimeofday (&tv, NULL);
447 ts.tv_sec = tv.tv_sec;
448 ts.tv_nsec = tv.tv_usec * 1000;
452 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
453 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
457 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
458 * No leap seconds during that period since they were not invented yet.
460 assert (t < 0x100000000);
461 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;