1 /*****************************************************************************
2 * mtime.c: high resolution time management functions
3 * Functions are prototyped in mtime.h.
4 *****************************************************************************
5 * Copyright (C) 1998-2001, 2003 VideoLAN
6 * $Id: mtime.c,v 1.38 2003/12/03 13:27:51 rocky Exp $
8 * Authors: Vincent Seguin <seguin@via.ecp.fr>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
23 *****************************************************************************/
27 * see if using Linux real-time extensions is possible and profitable
30 /*****************************************************************************
32 *****************************************************************************/
33 #include <stdio.h> /* sprintf() */
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 *);
67 /*****************************************************************************
68 * mstrtime: return a date in a readable format
69 *****************************************************************************
70 * This function converts a mtime date into a string.
71 * psz_buffer should be a buffer long enough to store the formatted
73 *****************************************************************************/
75 * \brief return a date in a readable format
76 * \param date to be converted
77 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
78 * \return psz_buffer is returned so this can be used as printf parameter.
80 char *mstrtime( char *psz_buffer, mtime_t date )
82 static mtime_t ll1000 = 1000, ll60 = 60, ll24 = 24;
84 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%02d:%02d:%02d-%03d.%03d",
85 (int) (date / (ll1000 * ll1000 * ll60 * ll60) % ll24),
86 (int) (date / (ll1000 * ll1000 * ll60) % ll60),
87 (int) (date / (ll1000 * ll1000) % ll60),
88 (int) (date / ll1000 % ll1000),
89 (int) (date % ll1000) );
93 /*****************************************************************************
94 * secstotimestr: convert seconds to a time in the format h:mm:ss
95 *****************************************************************************
96 * This function is provided for any interface function which need to print a
97 * time string in the format h:mm:ss
99 *****************************************************************************/
101 * \brief convert seconds to a time in the format h:mm:ss
102 * \param secs the date to be converted
103 * \param psz_buffer should be a buffer at least MSTRTIME_MAX_SIZE characters
104 * \return psz_buffer is returned so this can be used as printf parameter.
106 char *secstotimestr( char *psz_buffer, int i_seconds )
108 snprintf( psz_buffer, MSTRTIME_MAX_SIZE, "%d:%2.2d:%2.2d",
109 (int) (i_seconds / (60 *60)),
110 (int) ((i_seconds / 60) % 60),
111 (int) (i_seconds % 60) );
112 return( psz_buffer );
115 /*****************************************************************************
116 * mdate: return high precision date
117 *****************************************************************************
118 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
119 * ftime() function (1 kHz resolution).
120 *****************************************************************************/
121 mtime_t mdate( void )
123 #if defined( HAVE_KERNEL_OS_H )
124 return( real_time_clock_usecs() );
126 #elif defined( WIN32 ) || defined( UNDER_CE )
127 /* We don't need the real date, just the value of a high precision timer */
128 static mtime_t freq = I64C(-1);
131 if( freq == I64C(-1) )
133 /* Extract from the Tcl source code:
134 * (http://www.cs.man.ac.uk/fellowsd-bin/TIP/7.html)
136 * Some hardware abstraction layers use the CPU clock
137 * in place of the real-time clock as a performance counter
138 * reference. This results in:
139 * - inconsistent results among the processors on
140 * multi-processor systems.
141 * - unpredictable changes in performance counter frequency
142 * on "gearshift" processors such as Transmeta and
144 * There seems to be no way to test whether the performance
145 * counter is reliable, but a useful heuristic is that
146 * if its frequency is 1.193182 MHz or 3.579545 MHz, it's
147 * derived from a colorburst crystal and is therefore
148 * the RTC rather than the TSC. If it's anything else, we
149 * presume that the performance counter is unreliable.
152 freq = ( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) &&
153 (freq == I64C(1193182) || freq == I64C(3579545) ) )
159 /* Microsecond resolution */
160 QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
161 return ( usec_time * 1000000 ) / freq;
164 /* Milisecond resolution (actually, best case is about 10 ms resolution) */
165 return 1000 * GetTickCount();
168 struct timeval tv_date;
170 /* gettimeofday() could return an error, and should be tested. However, the
171 * only possible error, according to 'man', is EFAULT, which can not happen
172 * here, since tv is a local variable. */
173 gettimeofday( &tv_date, NULL );
174 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
179 /*****************************************************************************
180 * mwait: wait for a date
181 *****************************************************************************
182 * This function uses select() and an system date function to wake up at a
183 * precise date. It should be used for process synchronization. If current date
184 * is posterior to wished date, the function returns immediately.
185 *****************************************************************************/
186 void mwait( mtime_t date )
188 #if defined( HAVE_KERNEL_OS_H )
191 delay = date - real_time_clock_usecs();
198 #elif defined( WIN32 ) || defined( UNDER_CE )
199 mtime_t usec_time, delay;
202 delay = date - usec_time;
211 struct timeval tv_date;
212 mtime_t delay; /* delay in msec, signed to detect errors */
214 /* see mdate() about gettimeofday() possible errors */
215 gettimeofday( &tv_date, NULL );
217 /* calculate delay and check if current date is before wished date */
218 delay = date - (mtime_t) tv_date.tv_sec * 1000000
219 - (mtime_t) tv_date.tv_usec
222 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
223 * than to be late. */
224 if( delay <= 0 ) /* wished date is now or already passed */
229 # if defined( PTH_INIT_IN_PTH_H )
232 # elif defined( ST_INIT_IN_ST_H )
237 # if defined( HAVE_NANOSLEEP )
239 struct timespec ts_delay;
240 ts_delay.tv_sec = delay / 1000000;
241 ts_delay.tv_nsec = (delay % 1000000) * 1000;
243 nanosleep( &ts_delay, NULL );
247 tv_date.tv_sec = delay / 1000000;
248 tv_date.tv_usec = delay % 1000000;
249 /* see msleep() about select() errors */
250 select( 0, NULL, NULL, NULL, &tv_date );
258 /*****************************************************************************
259 * msleep: more precise sleep()
260 *****************************************************************************
261 * Portable usleep() function.
262 *****************************************************************************/
263 void msleep( mtime_t delay )
265 #if defined( HAVE_KERNEL_OS_H )
268 #elif defined( PTH_INIT_IN_PTH_H )
271 #elif defined( ST_INIT_IN_ST_H )
274 #elif defined( WIN32 ) || defined( UNDER_CE )
275 Sleep( (int) (delay / 1000) );
277 #elif defined( HAVE_NANOSLEEP )
278 struct timespec ts_delay;
280 ts_delay.tv_sec = delay / 1000000;
281 ts_delay.tv_nsec = (delay % 1000000) * 1000;
283 nanosleep( &ts_delay, NULL );
286 struct timeval tv_delay;
288 tv_delay.tv_sec = delay / 1000000;
289 tv_delay.tv_usec = delay % 1000000;
291 /* select() return value should be tested, since several possible errors
292 * can occur. However, they should only happen in very particular occasions
293 * (i.e. when a signal is sent to the thread, or when memory is full), and
295 select( 0, NULL, NULL, NULL, &tv_delay );