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> /* lldiv() */
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_NANOSLEEP)
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 return ((mtime_t)ts.tv_sec * (mtime_t)1000000)
201 + (mtime_t)(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_NANOSLEEP)
243 # if defined (HAVE_TIMER_ABSTIME_THAT_ACTUALLY_WORKS_WELL)
244 lldiv_t d = lldiv( date, 1000000 );
245 struct timespec ts = { d.quot, d.rem };
247 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
248 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
250 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
259 struct timeval tv_date;
260 mtime_t delay; /* delay in msec, signed to detect errors */
262 /* see mdate() about gettimeofday() possible errors */
263 gettimeofday( &tv_date, NULL );
265 /* calculate delay and check if current date is before wished date */
266 delay = date - (mtime_t) tv_date.tv_sec * 1000000
267 - (mtime_t) tv_date.tv_usec
270 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
271 * than to be late. */
272 if( delay <= 0 ) /* wished date is now or already passed */
277 # if defined( PTH_INIT_IN_PTH_H )
280 # elif defined( ST_INIT_IN_ST_H )
285 # if defined( HAVE_NANOSLEEP )
287 struct timespec ts_delay;
288 ts_delay.tv_sec = delay / 1000000;
289 ts_delay.tv_nsec = (delay % 1000000) * 1000;
291 nanosleep( &ts_delay, NULL );
295 tv_date.tv_sec = delay / 1000000;
296 tv_date.tv_usec = delay % 1000000;
297 /* see msleep() about select() errors */
298 select( 0, NULL, NULL, NULL, &tv_date );
307 * More precise sleep()
309 * Portable usleep() function.
310 * \param delay the amount of time to sleep
312 void msleep( mtime_t delay )
314 #if defined( HAVE_KERNEL_OS_H )
317 #elif defined( PTH_INIT_IN_PTH_H )
320 #elif defined( ST_INIT_IN_ST_H )
323 #elif defined( WIN32 ) || defined( UNDER_CE )
324 Sleep( (int) (delay / 1000) );
326 #elif defined( HAVE_CLOCK_NANOSLEEP )
327 lldiv_t d = lldiv( delay, 1000000 );
328 struct timespec ts = { d.quot, d.rem * 1000 };
330 # if (_POSIX_CLOCK_MONOTONIC - 0 >= 0)
331 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
333 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
335 #elif defined( HAVE_NANOSLEEP )
336 struct timespec ts_delay;
338 ts_delay.tv_sec = delay / 1000000;
339 ts_delay.tv_nsec = (delay % 1000000) * 1000;
341 nanosleep( &ts_delay, NULL );
344 struct timeval tv_delay;
346 tv_delay.tv_sec = delay / 1000000;
347 tv_delay.tv_usec = delay % 1000000;
349 /* select() return value should be tested, since several possible errors
350 * can occur. However, they should only happen in very particular occasions
351 * (i.e. when a signal is sent to the thread, or when memory is full), and
353 select( 0, NULL, NULL, NULL, &tv_delay );
359 * Date management (internal and external)
363 * Initialize a date_t.
365 * \param date to initialize
366 * \param divider (sample rate) numerator
367 * \param divider (sample rate) denominator
370 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
373 p_date->i_divider_num = i_divider_n;
374 p_date->i_divider_den = i_divider_d;
375 p_date->i_remainder = 0;
381 * \param date to change
382 * \param divider (sample rate) numerator
383 * \param divider (sample rate) denominator
386 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
388 p_date->i_divider_num = i_divider_n;
389 p_date->i_divider_den = i_divider_d;
393 * Set the date value of a date_t.
398 void date_Set( date_t *p_date, mtime_t i_new_date )
400 p_date->date = i_new_date;
401 p_date->i_remainder = 0;
405 * Get the date of a date_t
410 mtime_t date_Get( const date_t *p_date )
416 * Move forwards or backwards the date of a date_t.
418 * \param date to move
419 * \param difference value
421 void date_Move( date_t *p_date, mtime_t i_difference )
423 p_date->date += i_difference;
427 * Increment the date and return the result, taking into account
430 * \param date to increment
431 * \param incrementation in number of samples
434 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
436 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
437 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
438 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
440 if( p_date->i_remainder >= p_date->i_divider_num )
442 /* This is Bresenham algorithm. */
443 p_date->date += p_date->i_divider_den;
444 p_date->i_remainder -= p_date->i_divider_num;