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_CLOCK_NANOSLEEP)
121 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
122 /* Try to use POSIX monotonic clock if available */
123 if( clock_gettime( CLOCK_MONOTONIC, &ts ) )
125 /* Run-time fallback to real-time clock (always available) */
126 (void)clock_gettime( CLOCK_REALTIME, &ts );
128 return ((mtime_t)ts.tv_sec * (mtime_t)1000000)
129 + (mtime_t)(ts.tv_nsec / 1000);
131 #elif defined( HAVE_KERNEL_OS_H )
132 return( real_time_clock_usecs() );
134 #elif defined( WIN32 ) || defined( UNDER_CE )
135 /* We don't need the real date, just the value of a high precision timer */
136 static mtime_t freq = I64C(-1);
138 if( freq == I64C(-1) )
140 /* Extract from the Tcl source code:
141 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
143 * Some hardware abstraction layers use the CPU clock
144 * in place of the real-time clock as a performance counter
145 * reference. This results in:
146 * - inconsistent results among the processors on
147 * multi-processor systems.
148 * - unpredictable changes in performance counter frequency
149 * on "gearshift" processors such as Transmeta and
151 * There seems to be no way to test whether the performance
152 * counter is reliable, but a useful heuristic is that
153 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
154 * derived from a colorburst crystal and is therefore
155 * the RTC rather than the TSC. If it's anything else, we
156 * presume that the performance counter is unreliable.
160 freq = ( QueryPerformanceFrequency( &buf ) &&
161 (freq == I64C(1193182) || freq == I64C(3579545) ) )
167 LARGE_INTEGER counter;
168 QueryPerformanceCounter (&counter);
170 /* Convert to from (1/freq) to microsecond resolution */
171 /* We need to split the division to avoid 63-bits overflow */
172 lldiv_t d = lldiv (counter.QuadPart, freq);
174 return (d.quot * 1000000)
175 + ((d.rem * 1000000) / freq);
179 /* Fallback on GetTickCount() which has a milisecond resolution
180 * (actually, best case is about 10 ms resolution)
181 * GetTickCount() only returns a DWORD thus will wrap after
182 * about 49.7 days so we try to detect the wrapping. */
184 static CRITICAL_SECTION date_lock;
185 static mtime_t i_previous_time = I64C(-1);
186 static int i_wrap_counts = -1;
189 if( i_wrap_counts == -1 )
192 i_previous_time = I64C(1000) * GetTickCount();
193 InitializeCriticalSection( &date_lock );
197 EnterCriticalSection( &date_lock );
198 usec_time = I64C(1000) *
199 (i_wrap_counts * I64C(0x100000000) + GetTickCount());
200 if( i_previous_time > usec_time )
202 /* Counter wrapped */
204 usec_time += I64C(0x100000000000);
206 i_previous_time = usec_time;
207 LeaveCriticalSection( &date_lock );
212 struct timeval tv_date;
214 /* gettimeofday() cannot fail given &tv_date is a valid address */
215 (void)gettimeofday( &tv_date, NULL );
216 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
223 * This function uses select() and an system date function to wake up at a
224 * precise date. It should be used for process synchronization. If current date
225 * is posterior to wished date, the function returns immediately.
226 * \param date The date to wake up at
228 void mwait( mtime_t date )
230 #if defined (HAVE_CLOCK_NANOSLEEP)
231 lldiv_t d = lldiv( date, 1000000 );
232 struct timespec ts = { d.quot, d.rem * 1000 };
234 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
235 if( clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &ts, NULL ) )
237 clock_nanosleep( CLOCK_REALTIME, TIMER_ABSTIME, &ts, NULL );
240 mtime_t delay = mdate() - date;
248 * More precise sleep()
250 * Portable usleep() function.
251 * \param delay the amount of time to sleep
253 void msleep( mtime_t delay )
255 #if defined( HAVE_CLOCK_NANOSLEEP )
256 lldiv_t d = lldiv( delay, 1000000 );
257 struct timespec ts = { d.quot, d.rem * 1000 };
259 # if (_POSIX_MONOTONIC_CLOCK - 0 >= 0)
260 if( clock_nanosleep( CLOCK_MONOTONIC, 0, &ts, NULL ) )
262 clock_nanosleep( CLOCK_REALTIME, 0, &ts, NULL );
264 #elif defined( HAVE_KERNEL_OS_H )
267 #elif defined( PTH_INIT_IN_PTH_H )
270 #elif defined( ST_INIT_IN_ST_H )
273 #elif defined( WIN32 ) || defined( UNDER_CE )
274 Sleep( (int) (delay / 1000) );
276 #elif defined( HAVE_NANOSLEEP )
277 struct timespec ts_delay;
279 ts_delay.tv_sec = delay / 1000000;
280 ts_delay.tv_nsec = (delay % 1000000) * 1000;
282 nanosleep( &ts_delay, NULL );
285 struct timeval tv_delay;
287 tv_delay.tv_sec = delay / 1000000;
288 tv_delay.tv_usec = delay % 1000000;
290 /* select() return value should be tested, since several possible errors
291 * can occur. However, they should only happen in very particular occasions
292 * (i.e. when a signal is sent to the thread, or when memory is full), and
294 select( 0, NULL, NULL, NULL, &tv_delay );
299 * Date management (internal and external)
303 * Initialize a date_t.
305 * \param date to initialize
306 * \param divider (sample rate) numerator
307 * \param divider (sample rate) denominator
310 void date_Init( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
313 p_date->i_divider_num = i_divider_n;
314 p_date->i_divider_den = i_divider_d;
315 p_date->i_remainder = 0;
321 * \param date to change
322 * \param divider (sample rate) numerator
323 * \param divider (sample rate) denominator
326 void date_Change( date_t *p_date, uint32_t i_divider_n, uint32_t i_divider_d )
328 p_date->i_divider_num = i_divider_n;
329 p_date->i_divider_den = i_divider_d;
333 * Set the date value of a date_t.
338 void date_Set( date_t *p_date, mtime_t i_new_date )
340 p_date->date = i_new_date;
341 p_date->i_remainder = 0;
345 * Get the date of a date_t
350 mtime_t date_Get( const date_t *p_date )
356 * Move forwards or backwards the date of a date_t.
358 * \param date to move
359 * \param difference value
361 void date_Move( date_t *p_date, mtime_t i_difference )
363 p_date->date += i_difference;
367 * Increment the date and return the result, taking into account
370 * \param date to increment
371 * \param incrementation in number of samples
374 mtime_t date_Increment( date_t *p_date, uint32_t i_nb_samples )
376 mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
377 p_date->date += i_dividend / p_date->i_divider_num * p_date->i_divider_den;
378 p_date->i_remainder += (int)(i_dividend % p_date->i_divider_num);
380 if( p_date->i_remainder >= p_date->i_divider_num )
382 /* This is Bresenham algorithm. */
383 p_date->date += p_date->i_divider_den;
384 p_date->i_remainder -= p_date->i_divider_num;