1 /*****************************************************************************
2 * mtime.c: high resolution time management functions
3 * Functions are prototyped in mtime.h.
4 *****************************************************************************
5 * Copyright (C) 1998-2004 the VideoLAN team
8 * Authors: Vincent Seguin <seguin@via.ecp.fr>
9 * RĂ©mi Denis-Courmont <rem$videolan,org>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
24 *****************************************************************************/
26 /*****************************************************************************
28 *****************************************************************************/
29 #include <stdio.h> /* sprintf() */
30 #include <time.h> /* clock_gettime(), clock_nanosleep() */
31 #include <stdlib.h> /* ldiv() */
35 #if defined( PTH_INIT_IN_PTH_H ) /* GNU Pth */
40 # include <unistd.h> /* select() */
43 #ifdef HAVE_KERNEL_OS_H
44 # include <kernel/OS.h>
47 #if defined( WIN32 ) || defined( UNDER_CE )
50 # include <sys/time.h>
53 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_STRUCT_TIMESPEC)
61 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
62 int nanosleep(struct timespec *, struct timespec *);
66 * Return a date in a readable format
68 * This function converts a mtime date into a string.
69 * psz_buffer should be a buffer long enough to store the formatted
71 * \param date to be converted
72 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
73 * \return psz_buffer is returned so this can be used as printf parameter.
75 char *mstrtime( char *psz_buffer, mtime_t date )
77 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
79 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
80 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
81 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
82 (int) (date / (ll1000 * ll1000) % ll60),
83 (int) (date / ll1000 % ll1000),
84 (int) (date % ll1000) );
89 * Convert seconds to a time in the format h:mm:ss.
91 * This function is provided for any interface function which need to print a
92 * time string in the format h:mm:ss
94 * \param secs the 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 *secstotimestr( char *psz_buffer, int i_seconds )
100 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
101 (int) (i_seconds / (60 *60)),
102 (int) ((i_seconds / 60) % 60),
103 (int) (i_seconds % 60) );
104 return( psz_buffer );
109 * Return high precision date
111 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
112 * ftime() function (1 kHz resolution).
114 mtime_t mdate( void )
116 #if defined( HAVE_KERNEL_OS_H )
117 return( real_time_clock_usecs() );
119 #elif defined( WIN32 ) || defined( UNDER_CE )
120 /* We don't need the real date, just the value of a high precision timer */
121 static mtime_t freq = I64C(-1);
124 if( freq == I64C(-1) )
126 /* Extract from the Tcl source code:
127 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
129 * Some hardware abstraction layers use the CPU clock
130 * in place of the real-time clock as a performance counter
131 * reference. This results in:
132 * - inconsistent results among the processors on
133 * multi-processor systems.
134 * - unpredictable changes in performance counter frequency
135 * on "gearshift" processors such as Transmeta and
137 * There seems to be no way to test whether the performance
138 * counter is reliable, but a useful heuristic is that
139 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
140 * derived from a colorburst crystal and is therefore
141 * the RTC rather than the TSC. If it's anything else, we
142 * presume that the performance counter is unreliable.
145 freq = ( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) &&
146 (freq == I64C(1193182) || freq == I64C(3579545) ) )
152 /* Microsecond resolution */
153 QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
154 return ( usec_time * 1000000 ) / freq;
158 /* Fallback on GetTickCount() which has a milisecond resolution
159 * (actually, best case is about 10 ms resolution)
160 * GetTickCount() only returns a DWORD thus will wrap after
161 * about 49.7 days so we try to detect the wrapping. */
163 static CRITICAL_SECTION date_lock;
164 static mtime_t i_previous_time = I64C(-1);
165 static int i_wrap_counts = -1;
167 if( i_wrap_counts == -1 )
170 i_previous_time = I64C(1000) * GetTickCount();
171 InitializeCriticalSection( &date_lock );
175 EnterCriticalSection( &date_lock );
176 usec_time = I64C(1000) *
177 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
178 if( i_previous_time > usec_time )
180 /* Counter wrapped */
182 usec_time += I64C(0x100000000000);
184 i_previous_time = usec_time;
185 LeaveCriticalSection( &date_lock );
190 #elif defined (HAVE_CLOCK_GETTIME)
193 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
194 /* Try to use POSIX monotonic clock if available */
195 if( clock_gettime( CLOCK_MONOTONIC, &ts ) )
197 /* Run-time fallback to real-time clock (always available) */
198 (void)clock_gettime( CLOCK_REALTIME, &ts );
200 fprintf (stderr, "%ld\n", (mtime_t)((ts.tv_sec * 1000000) + (ts.tv_nsec / 1000)));
201 return (ts.tv_sec * 1000000) + (ts.tv_nsec / 1000);
203 struct timeval tv_date;
205 /* gettimeofday() cannot fail given &tv_date is a valid address */
206 (void)gettimeofday( &tv_date, NULL );
207 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
214 * This function uses select() and an system date function to wake up at a
215 * precise date. It should be used for process synchronization. If current date
216 * is posterior to wished date, the function returns immediately.
217 * \param date The date to wake up at
219 void mwait( mtime_t date )
221 #if defined( HAVE_KERNEL_OS_H )
224 delay = date - real_time_clock_usecs();
231 #elif defined( WIN32 ) || defined( UNDER_CE )
232 mtime_t usec_time, delay;
235 delay = date - usec_time;
242 #elif defined (HAVE_CLOCK_GETTIME)
248 * Ideally, we'd use absolute time (TIMER_ABSTIME), instead of
249 * computing the time difference... but VLC mtime_t type seems to
250 * overflow way too quickly for this to work properly, or maybe it's a
251 * signedness problem (??).
257 d = ldiv( date, 1000000 );
259 ts.tv_nsec = d.rem * 1000;
261 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
262 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
264 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
267 struct timeval tv_date;
268 mtime_t delay; /* delay in msec, signed to detect errors */
270 /* see mdate() about gettimeofday() possible errors */
271 gettimeofday( &tv_date, NULL );
273 /* calculate delay and check if current date is before wished date */
274 delay = date - (mtime_t) tv_date.tv_sec * 1000000
275 - (mtime_t) tv_date.tv_usec
278 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
279 * than to be late. */
280 if( delay <= 0 ) /* wished date is now or already passed */
285 # if defined( PTH_INIT_IN_PTH_H )
288 # elif defined( ST_INIT_IN_ST_H )
293 # if defined( HAVE_NANOSLEEP )
295 struct timespec ts_delay;
296 ts_delay.tv_sec = delay / 1000000;
297 ts_delay.tv_nsec = (delay % 1000000) * 1000;
299 nanosleep( &ts_delay, NULL );
303 tv_date.tv_sec = delay / 1000000;
304 tv_date.tv_usec = delay % 1000000;
305 /* see msleep() about select() errors */
306 select( 0, NULL, NULL, NULL, &tv_date );
315 * More precise sleep()
317 * Portable usleep() function.
318 * \param delay the amount of time to sleep
320 void msleep( mtime_t delay )
322 #if defined( HAVE_KERNEL_OS_H )
325 #elif defined( PTH_INIT_IN_PTH_H )
328 #elif defined( ST_INIT_IN_ST_H )
331 #elif defined( WIN32 ) || defined( UNDER_CE )
332 Sleep( (int) (delay / 1000) );
334 #elif defined( HAVE_CLOCK_GETTIME )
335 ldiv_t d = ldiv( delay, 1000000 );
336 struct timespec ts = { d.quot, d.rem * 1000 };
337 # if (_POSIX_CLOCK_MONOTONIC - 0 >= 0)
338 if (clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
340 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
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 nanosleep( &ts_delay, NULL );
351 struct timeval tv_delay;
353 tv_delay.tv_sec = delay / 1000000;
354 tv_delay.tv_usec = delay % 1000000;
356 /* select() return value should be tested, since several possible errors
357 * can occur. However, they should only happen in very particular occasions
358 * (i.e. when a signal is sent to the thread, or when memory is full), and
360 select( 0, NULL, NULL, NULL, &tv_delay );
366 * Date management (internal and external)
370 * Initialize a date_t.
372 * \param date to initialize
373 * \param divider (sample rate) numerator
374 * \param divider (sample rate) denominator
377 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
380 p_date->i_divider_num = i_divider_n;
381 p_date->i_divider_den = i_divider_d;
382 p_date->i_remainder = 0;
388 * \param date to change
389 * \param divider (sample rate) numerator
390 * \param divider (sample rate) denominator
393 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
395 p_date->i_divider_num = i_divider_n;
396 p_date->i_divider_den = i_divider_d;
400 * Set the date value of a date_t.
405 void date_Set( date_t *p_date, mtime_t i_new_date )
407 p_date->date = i_new_date;
408 p_date->i_remainder = 0;
412 * Get the date of a date_t
417 mtime_t date_Get( const date_t *p_date )
423 * Move forwards or backwards the date of a date_t.
425 * \param date to move
426 * \param difference value
428 void date_Move( date_t *p_date, mtime_t i_difference )
430 p_date->date += i_difference;
434 * Increment the date and return the result, taking into account
437 * \param date to increment
438 * \param incrementation in number of samples
441 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
443 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
444 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
445 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
447 if( p_date->i_remainder >= p_date->i_divider_num )
449 /* This is Bresenham algorithm. */
450 p_date->date += p_date->i_divider_den;
451 p_date->i_remainder -= p_date->i_divider_num;