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);
163 if( freq == I64C(-1) )
165 /* Extract from the Tcl source code:
166 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
168 * Some hardware abstraction layers use the CPU clock
169 * in place of the real-time clock as a performance counter
170 * reference. This results in:
171 * - inconsistent results among the processors on
172 * multi-processor systems.
173 * - unpredictable changes in performance counter frequency
174 * on "gearshift" processors such as Transmeta and
176 * There seems to be no way to test whether the performance
177 * counter is reliable, but a useful heuristic is that
178 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
179 * derived from a colorburst crystal and is therefore
180 * the RTC rather than the TSC. If it's anything else, we
181 * presume that the performance counter is unreliable.
185 freq = ( QueryPerformanceFrequency( &buf ) &&
186 (buf.QuadPart == I64C(1193182) || buf.QuadPart == I64C(3579545) ) )
192 LARGE_INTEGER counter;
193 QueryPerformanceCounter (&counter);
195 /* Convert to from (1/freq) to microsecond resolution */
196 /* We need to split the division to avoid 63-bits overflow */
197 lldiv_t d = lldiv (counter.QuadPart, freq);
199 res = (d.quot * 1000000) + ((d.rem * 1000000) / freq);
203 /* Fallback on GetTickCount() which has a milisecond resolution
204 * (actually, best case is about 10 ms resolution)
205 * GetTickCount() only returns a DWORD thus will wrap after
206 * about 49.7 days so we try to detect the wrapping. */
208 static CRITICAL_SECTION date_lock;
209 static mtime_t i_previous_time = I64C(-1);
210 static int i_wrap_counts = -1;
212 if( i_wrap_counts == -1 )
215 i_previous_time = I64C(1000) * GetTickCount();
216 InitializeCriticalSection( &date_lock );
220 EnterCriticalSection( &date_lock );
222 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
223 if( i_previous_time > res )
225 /* Counter wrapped */
227 usec_time += I64C(0x100000000) * 1000;
229 i_previous_time = usec_time;
230 LeaveCriticalSection( &date_lock );
233 struct timeval tv_date;
235 /* gettimeofday() cannot fail given &tv_date is a valid address */
236 (void)gettimeofday( &tv_date, NULL );
237 res = (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec;
240 return cached_time = res;
246 * This function uses select() and an system date function to wake up at a
247 * precise date. It should be used for process synchronization. If current date
248 * is posterior to wished date, the function returns immediately.
249 * \param date The date to wake up at
251 void mwait( mtime_t date )
256 /* If the deadline is already elapsed, or within the clock precision,
257 * do not even bother the clock. */
258 if( ( date - cached_time ) < (mtime_t)prec ) // OK: mtime_t is signed
261 #if 0 && defined (HAVE_CLOCK_NANOSLEEP)
262 lldiv_t d = lldiv( date, 1000000 );
263 struct timespec ts = { d.quot, d.rem * 1000 };
265 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
266 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
268 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
271 mtime_t delay = date - mdate();
279 * More precise sleep()
281 * Portable usleep() function.
282 * \param delay the amount of time to sleep
284 void msleep( mtime_t delay )
286 mtime_t earlier = cached_time;
288 #if defined( HAVE_CLOCK_NANOSLEEP )
289 lldiv_t d = lldiv( delay, 1000000 );
290 struct timespec ts = { d.quot, d.rem * 1000 };
292 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
293 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
295 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
297 #elif defined( HAVE_KERNEL_OS_H )
300 #elif defined( PTH_INIT_IN_PTH_H )
303 #elif defined( ST_INIT_IN_ST_H )
306 #elif defined( WIN32 ) || defined( UNDER_CE )
307 Sleep( (int) (delay / 1000) );
309 #elif defined( HAVE_NANOSLEEP )
310 struct timespec ts_delay;
312 ts_delay.tv_sec = delay / 1000000;
313 ts_delay.tv_nsec = (delay % 1000000) * 1000;
315 nanosleep( &ts_delay, NULL );
318 struct timeval tv_delay;
320 tv_delay.tv_sec = delay / 1000000;
321 tv_delay.tv_usec = delay % 1000000;
323 /* select() return value should be tested, since several possible errors
324 * can occur. However, they should only happen in very particular occasions
325 * (i.e. when a signal is sent to the thread, or when memory is full), and
327 select( 0, NULL, NULL, NULL, &tv_delay );
331 if( cached_time < earlier )
332 cached_time = earlier;
336 * Date management (internal and external)
340 * Initialize a date_t.
342 * \param date to initialize
343 * \param divider (sample rate) numerator
344 * \param divider (sample rate) denominator
347 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
350 p_date->i_divider_num = i_divider_n;
351 p_date->i_divider_den = i_divider_d;
352 p_date->i_remainder = 0;
358 * \param date to change
359 * \param divider (sample rate) numerator
360 * \param divider (sample rate) denominator
363 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
365 p_date->i_divider_num = i_divider_n;
366 p_date->i_divider_den = i_divider_d;
370 * Set the date value of a date_t.
375 void date_Set( date_t *p_date, mtime_t i_new_date )
377 p_date->date = i_new_date;
378 p_date->i_remainder = 0;
382 * Get the date of a date_t
387 mtime_t date_Get( const date_t *p_date )
393 * Move forwards or backwards the date of a date_t.
395 * \param date to move
396 * \param difference value
398 void date_Move( date_t *p_date, mtime_t i_difference )
400 p_date->date += i_difference;
404 * Increment the date and return the result, taking into account
407 * \param date to increment
408 * \param incrementation in number of samples
411 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
413 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
414 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
415 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
417 if( p_date->i_remainder >= p_date->i_divider_num )
419 /* This is Bresenham algorithm. */
420 p_date->date += p_date->i_divider_den;
421 p_date->i_remainder -= p_date->i_divider_num;
429 * Number of micro-seconds between the beginning of the Windows epoch
430 * (Jan. 1, 1601) and the Unix epoch (Jan. 1, 1970).
432 * This assumes all Win32 compilers have 64-bit support.
434 #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) || defined(__WATCOMC__)
435 # define DELTA_EPOCH_IN_USEC 11644473600000000Ui64
437 # define DELTA_EPOCH_IN_USEC 11644473600000000ULL
440 static uint64_t filetime_to_unix_epoch (const FILETIME *ft)
442 uint64_t res = (uint64_t) ft->dwHighDateTime << 32;
444 res |= ft->dwLowDateTime;
445 res /= 10; /* from 100 nano-sec periods to usec */
446 res -= DELTA_EPOCH_IN_USEC; /* from Win epoch to Unix epoch */
450 static int gettimeofday (struct timeval *tv, void *tz )
458 GetSystemTimeAsFileTime (&ft);
459 tim = filetime_to_unix_epoch (&ft);
460 tv->tv_sec = (long) (tim / 1000000L);
461 tv->tv_usec = (long) (tim % 1000000L);
469 * @return NTP 64-bits timestamp in host byte order.
471 uint64_t NTPtime64 (void)
474 #if defined (CLOCK_REALTIME)
475 clock_gettime (CLOCK_REALTIME, &ts);
479 gettimeofday (&tv, NULL);
480 ts.tv_sec = tv.tv_sec;
481 ts.tv_nsec = tv.tv_usec * 1000;
485 /* Convert nanoseconds to 32-bits fraction (232 picosecond units) */
486 uint64_t t = (uint64_t)(ts.tv_nsec) << 32;
490 /* There is 70 years (incl. 17 leap ones) offset to the Unix Epoch.
491 * No leap seconds during that period since they were not invented yet.
493 assert (t < 0x100000000);
494 t |= ((70LL * 365 + 17) * 24 * 60 * 60 + ts.tv_sec) << 32;