1 /*****************************************************************************
2 * mtime.c: high rezolution time management functions
3 * Functions are prototyped in mtime.h.
4 *****************************************************************************
5 * Copyright (C) 1998, 1999, 2000 VideoLAN
6 * $Id: mtime.c,v 1.23 2001/06/14 20:21:04 sam 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 *****************************************************************************/
35 #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>
52 # include <sys/time.h>
60 /*****************************************************************************
61 * usleep: microsecond sleep for win32
62 *****************************************************************************
63 * This function uses performance counter if available, and Sleep() if not.
64 *****************************************************************************/
65 static __inline__ void usleep( unsigned int i_useconds )
71 && QueryPerformanceFrequency( (LARGE_INTEGER *) &i_freq ) )
73 QueryPerformanceCounter( (LARGE_INTEGER *) &i_cur );
75 i_now = ( i_cur * 1000 * 1000 / i_freq );
76 i_then = i_now + i_useconds;
78 while( i_now < i_then )
80 QueryPerformanceCounter( (LARGE_INTEGER *) &i_cur );
81 i_now = i_cur * 1000 * 1000 / i_freq;
86 Sleep( (int) ((i_useconds + 500) / 1000) );
91 /*****************************************************************************
92 * mstrtime: return a date in a readable format
93 *****************************************************************************
94 * This functions is provided for any interface function which need to print a
95 * date. psz_buffer should be a buffer long enough to store the formatted
97 *****************************************************************************/
98 char *mstrtime( char *psz_buffer, mtime_t date )
100 sprintf( psz_buffer, "%02d:%02d:%02d-%03d.%03d",
101 (int) (date / (I64C(1000) * I64C(1000) * I64C(60) * I64C(60)) % I64C(24)),
102 (int) (date / (I64C(1000) * I64C(1000) * I64C(60)) % I64C(60)),
103 (int) (date / (I64C(1000) * I64C(1000)) % I64C(60)),
104 (int) (date / I64C(1000) % I64C(1000)),
105 (int) (date % I64C(1000)) );
106 return( psz_buffer );
109 /*****************************************************************************
110 * mdate: return high precision date (inline function)
111 *****************************************************************************
112 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
113 * ftime() function (1 kHz resolution).
114 *****************************************************************************/
115 mtime_t mdate( void )
117 #if defined( HAVE_KERNEL_OS_H )
118 return( real_time_clock_usecs() );
120 #elif defined( WIN32 )
121 /* We don't get the real date, just the value of a high precision timer.
122 * this is because the usual time functions have at best only a milisecond
124 mtime_t freq, usec_time;
126 if( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) )
128 /* Microsecond resolution */
129 QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
130 return ( usec_time * 1000000 ) / freq;
134 /* Milisecond resolution */
135 return 1000 * GetTickCount();
139 struct timeval tv_date;
141 /* gettimeofday() could return an error, and should be tested. However, the
142 * only possible error, according to 'man', is EFAULT, which can not happen
143 * here, since tv is a local variable. */
144 gettimeofday( &tv_date, NULL );
145 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
150 /*****************************************************************************
151 * mwait: wait for a date (inline function)
152 *****************************************************************************
153 * This function uses select() and an system date function to wake up at a
154 * precise date. It should be used for process synchronization. If current date
155 * is posterior to wished date, the function returns immediately.
156 *****************************************************************************/
157 void mwait( mtime_t date )
159 #if defined( HAVE_KERNEL_OS_H )
162 delay = date - real_time_clock_usecs();
169 #elif defined( WIN32 )
170 mtime_t usec_time, delay;
173 delay = date - usec_time;
184 struct timeval tv_date;
186 struct timeval tv_date, tv_delay;
188 mtime_t delay; /* delay in msec, signed to detect errors */
190 /* see mdate() about gettimeofday() possible errors */
191 gettimeofday( &tv_date, NULL );
193 /* calculate delay and check if current date is before wished date */
194 delay = date - (mtime_t) tv_date.tv_sec * 1000000
195 - (mtime_t) tv_date.tv_usec
198 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
199 * than to be late. */
200 if( delay <= 0 ) /* wished date is now or already passed */
205 # if defined( PTH_INIT_IN_PTH_H )
208 # elif defined( HAVE_USLEEP )
212 tv_delay.tv_sec = delay / 1000000;
213 tv_delay.tv_usec = delay % 1000000;
214 /* see msleep() about select() errors */
215 select( 0, NULL, NULL, NULL, &tv_delay );
222 /*****************************************************************************
223 * msleep: more precise sleep() (inline function) (ok ?)
224 *****************************************************************************
225 * Portable usleep() function.
226 *****************************************************************************/
227 void msleep( mtime_t delay )
229 #if defined( HAVE_KERNEL_OS_H )
232 #elif defined( PTH_INIT_IN_PTH_H )
233 struct timeval tv_delay;
234 tv_delay.tv_sec = delay / 1000000;
235 tv_delay.tv_usec = delay % 1000000;
236 pth_select( 0, NULL, NULL, NULL, &tv_delay );
238 #elif defined( HAVE_USLEEP ) || defined( WIN32 )
242 struct timeval tv_delay;
244 tv_delay.tv_sec = delay / 1000000;
245 tv_delay.tv_usec = delay % 1000000;
246 /* select() return value should be tested, since several possible errors
247 * can occur. However, they should only happen in very particular occasions
248 * (i.e. when a signal is sent to the thread, or when memory is full), and
249 * can be ingnored. */
250 select( 0, NULL, NULL, NULL, &tv_delay );