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 *****************************************************************************/
32 #include <stdio.h> /* sprintf() */
33 #include <time.h> /* clock_gettime(), clock_nanosleep() */
34 #include <stdlib.h> /* lldiv() */
37 #if defined( PTH_INIT_IN_PTH_H ) /* GNU Pth */
42 # include <unistd.h> /* select() */
45 #ifdef HAVE_KERNEL_OS_H
46 # include <kernel/OS.h>
49 #if defined( WIN32 ) || defined( UNDER_CE )
52 # include <sys/time.h>
55 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_STRUCT_TIMESPEC)
63 #if defined(HAVE_NANOSLEEP) && !defined(HAVE_DECL_NANOSLEEP)
64 int nanosleep(struct timespec *, struct timespec *);
68 * Return a date in a readable format
70 * This function converts a mtime date into a string.
71 * psz_buffer should be a buffer long enough to store the formatted
73 * \param date to be converted
74 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
75 * \return psz_buffer is returned so this can be used as printf parameter.
77 char *mstrtime( char *psz_buffer, mtime_t date )
79 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
81 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
82 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
83 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
84 (int) (date / (ll1000 * ll1000) % ll60),
85 (int) (date / ll1000 % ll1000),
86 (int) (date % ll1000) );
91 * Convert seconds to a time in the format h:mm:ss.
93 * This function is provided for any interface function which need to print a
94 * time string in the format h:mm:ss
96 * \param secs the date to be converted
97 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
98 * \return psz_buffer is returned so this can be used as printf parameter.
100 char *secstotimestr( char *psz_buffer, int i_seconds )
102 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
103 (int) (i_seconds / (60 *60)),
104 (int) ((i_seconds / 60) % 60),
105 (int) (i_seconds % 60) );
106 return( psz_buffer );
111 * Return high precision date
113 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
114 * ftime() function (1 kHz resolution).
116 mtime_t mdate( void )
118 #if defined( HAVE_KERNEL_OS_H )
119 return( real_time_clock_usecs() );
121 #elif defined( WIN32 ) || defined( UNDER_CE )
122 /* We don't need the real date, just the value of a high precision timer */
123 static mtime_t freq = I64C(-1);
126 if( freq == I64C(-1) )
128 /* Extract from the Tcl source code:
129 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
131 * Some hardware abstraction layers use the CPU clock
132 * in place of the real-time clock as a performance counter
133 * reference. This results in:
134 * - inconsistent results among the processors on
135 * multi-processor systems.
136 * - unpredictable changes in performance counter frequency
137 * on "gearshift" processors such as Transmeta and
139 * There seems to be no way to test whether the performance
140 * counter is reliable, but a useful heuristic is that
141 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
142 * derived from a colorburst crystal and is therefore
143 * the RTC rather than the TSC. If it's anything else, we
144 * presume that the performance counter is unreliable.
147 freq = ( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) &&
148 (freq == I64C(1193182) || freq == I64C(3579545) ) )
154 /* Microsecond resolution */
155 QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
156 return ( usec_time * 1000000 ) / freq;
160 /* Fallback on GetTickCount() which has a milisecond resolution
161 * (actually, best case is about 10 ms resolution)
162 * GetTickCount() only returns a DWORD thus will wrap after
163 * about 49.7 days so we try to detect the wrapping. */
165 static CRITICAL_SECTION date_lock;
166 static mtime_t i_previous_time = I64C(-1);
167 static int i_wrap_counts = -1;
169 if( i_wrap_counts == -1 )
172 i_previous_time = I64C(1000) * GetTickCount();
173 InitializeCriticalSection( &date_lock );
177 EnterCriticalSection( &date_lock );
178 usec_time = I64C(1000) *
179 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
180 if( i_previous_time > usec_time )
182 /* Counter wrapped */
184 usec_time += I64C(0x100000000000);
186 i_previous_time = usec_time;
187 LeaveCriticalSection( &date_lock );
192 #elif defined (HAVE_CLOCK_NANOSLEEP)
195 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
196 /* Try to use POSIX monotonic clock if available */
197 if( clock_gettime( CLOCK_MONOTONIC, &ts ) )
199 /* Run-time fallback to real-time clock (always available) */
200 (void)clock_gettime( CLOCK_REALTIME, &ts );
202 return ((mtime_t)ts.tv_sec * (mtime_t)1000000)
203 + (mtime_t)(ts.tv_nsec / 1000);
205 struct timeval tv_date;
207 /* gettimeofday() cannot fail given &tv_date is a valid address */
208 (void)gettimeofday( &tv_date, NULL );
209 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
216 * This function uses select() and an system date function to wake up at a
217 * precise date. It should be used for process synchronization. If current date
218 * is posterior to wished date, the function returns immediately.
219 * \param date The date to wake up at
221 void mwait( mtime_t date )
223 #if defined( HAVE_KERNEL_OS_H )
226 delay = date - real_time_clock_usecs();
233 #elif defined( WIN32 ) || defined( UNDER_CE )
234 mtime_t usec_time, delay;
237 delay = date - usec_time;
244 #elif defined (HAVE_CLOCK_NANOSLEEP)
245 # if defined (HAVE_TIMER_ABSTIME_THAT_ACTUALLY_WORKS_WELL)
246 lldiv_t d = lldiv( date, 1000000 );
247 struct timespec ts = { d.quot, d.rem };
249 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
250 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
252 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
261 struct timeval tv_date;
262 mtime_t delay; /* delay in msec, signed to detect errors */
264 /* see mdate() about gettimeofday() possible errors */
265 gettimeofday( &tv_date, NULL );
267 /* calculate delay and check if current date is before wished date */
268 delay = date - (mtime_t) tv_date.tv_sec * 1000000
269 - (mtime_t) tv_date.tv_usec
272 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
273 * than to be late. */
274 if( delay <= 0 ) /* wished date is now or already passed */
279 # if defined( PTH_INIT_IN_PTH_H )
282 # elif defined( ST_INIT_IN_ST_H )
287 # if defined( HAVE_NANOSLEEP )
289 struct timespec ts_delay;
290 ts_delay.tv_sec = delay / 1000000;
291 ts_delay.tv_nsec = (delay % 1000000) * 1000;
293 nanosleep( &ts_delay, NULL );
297 tv_date.tv_sec = delay / 1000000;
298 tv_date.tv_usec = delay % 1000000;
299 /* see msleep() about select() errors */
300 select( 0, NULL, NULL, NULL, &tv_date );
309 * More precise sleep()
311 * Portable usleep() function.
312 * \param delay the amount of time to sleep
314 void msleep( mtime_t delay )
316 #if defined( HAVE_KERNEL_OS_H )
319 #elif defined( PTH_INIT_IN_PTH_H )
322 #elif defined( ST_INIT_IN_ST_H )
325 #elif defined( WIN32 ) || defined( UNDER_CE )
326 Sleep( (int) (delay / 1000) );
328 #elif defined( HAVE_CLOCK_NANOSLEEP )
329 lldiv_t d = lldiv( delay, 1000000 );
330 struct timespec ts = { d.quot, d.rem * 1000 };
332 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
333 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
335 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
337 #elif defined( HAVE_NANOSLEEP )
338 struct timespec ts_delay;
340 ts_delay.tv_sec = delay / 1000000;
341 ts_delay.tv_nsec = (delay % 1000000) * 1000;
343 nanosleep( &ts_delay, NULL );
346 struct timeval tv_delay;
348 tv_delay.tv_sec = delay / 1000000;
349 tv_delay.tv_usec = delay % 1000000;
351 /* select() return value should be tested, since several possible errors
352 * can occur. However, they should only happen in very particular occasions
353 * (i.e. when a signal is sent to the thread, or when memory is full), and
355 select( 0, NULL, NULL, NULL, &tv_delay );
361 * Date management (internal and external)
365 * Initialize a date_t.
367 * \param date to initialize
368 * \param divider (sample rate) numerator
369 * \param divider (sample rate) denominator
372 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
375 p_date->i_divider_num = i_divider_n;
376 p_date->i_divider_den = i_divider_d;
377 p_date->i_remainder = 0;
383 * \param date to change
384 * \param divider (sample rate) numerator
385 * \param divider (sample rate) denominator
388 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
390 p_date->i_divider_num = i_divider_n;
391 p_date->i_divider_den = i_divider_d;
395 * Set the date value of a date_t.
400 void date_Set( date_t *p_date, mtime_t i_new_date )
402 p_date->date = i_new_date;
403 p_date->i_remainder = 0;
407 * Get the date of a date_t
412 mtime_t date_Get( const date_t *p_date )
418 * Move forwards or backwards the date of a date_t.
420 * \param date to move
421 * \param difference value
423 void date_Move( date_t *p_date, mtime_t i_difference )
425 p_date->date += i_difference;
429 * Increment the date and return the result, taking into account
432 * \param date to increment
433 * \param incrementation in number of samples
436 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
438 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
439 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
440 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
442 if( p_date->i_remainder >= p_date->i_divider_num )
444 /* This is Bresenham algorithm. */
445 p_date->date += p_date->i_divider_den;
446 p_date->i_remainder -= p_date->i_divider_num;