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 1.20 2001/05/31 03:12:49 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() */
38 # include <unistd.h> /* select() */
41 #ifdef HAVE_KERNEL_OS_H
42 # include <kernel/OS.h>
48 # include <sys/time.h>
56 /*****************************************************************************
57 * usleep: microsecond sleep for win32
58 *****************************************************************************
59 * This function uses performance counter if available, and Sleep() if not.
60 *****************************************************************************/
61 static __inline__ void usleep( unsigned int i_useconds )
67 && QueryPerformanceFrequency( (LARGE_INTEGER *) &i_freq ) )
69 QueryPerformanceCounter( (LARGE_INTEGER *) &i_cur );
71 i_now = ( cur * 1000 * 1000 / i_freq );
72 i_then = i_now + i_useconds;
74 while( i_now < i_then )
76 QueryPerformanceCounter( (LARGE_INTEGER *) &i_cur );
77 now = cur * 1000 * 1000 / i_freq;
82 Sleep( (int) ((i_useconds + 500) / 1000) );
87 /*****************************************************************************
88 * mstrtime: return a date in a readable format
89 *****************************************************************************
90 * This functions is provided for any interface function which need to print a
91 * date. psz_buffer should be a buffer long enough to store the formatted
93 *****************************************************************************/
94 char *mstrtime( char *psz_buffer, mtime_t date )
96 sprintf( psz_buffer, "%02d:%02d:%02d-%03d.%03d",
97 (int) (date / (I64C(1000) * I64C(1000) * I64C(60) * I64C(60)) % I64C(24)),
98 (int) (date / (I64C(1000) * I64C(1000) * I64C(60)) % I64C(60)),
99 (int) (date / (I64C(1000) * I64C(1000)) % I64C(60)),
100 (int) (date / I64C(1000) % I64C(1000)),
101 (int) (date % I64C(1000)) );
102 return( psz_buffer );
105 /*****************************************************************************
106 * mdate: return high precision date (inline function)
107 *****************************************************************************
108 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
109 * ftime() function (1 kHz resolution).
110 *****************************************************************************/
111 mtime_t mdate( void )
113 #if defined( HAVE_KERNEL_OS_H )
114 return( real_time_clock_usecs() );
116 #elif defined( WIN32 )
117 /* We don't get the real date, just the value of a high precision timer.
118 * this is because the usual time functions have at best only a milisecond
120 mtime_t freq, usec_time;
122 if( QueryPerformanceFrequency( (LARGE_INTEGER *)&freq ) )
124 /* Microsecond resolution */
125 QueryPerformanceCounter( (LARGE_INTEGER *)&usec_time );
126 return ( usec_time * 1000000 ) / freq;
130 /* Milisecond resolution */
131 return 1000 * GetTickCount();
135 struct timeval tv_date;
137 /* gettimeofday() could return an error, and should be tested. However, the
138 * only possible error, according to 'man', is EFAULT, which can not happen
139 * here, since tv is a local variable. */
140 gettimeofday( &tv_date, NULL );
141 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
146 /*****************************************************************************
147 * mwait: wait for a date (inline function)
148 *****************************************************************************
149 * This function uses select() and an system date function to wake up at a
150 * precise date. It should be used for process synchronization. If current date
151 * is posterior to wished date, the function returns immediately.
152 *****************************************************************************/
153 void mwait( mtime_t date )
155 #if defined( HAVE_KERNEL_OS_H )
158 delay = date - real_time_clock_usecs();
165 #elif defined( WIN32 )
166 mtime_t usec_time, delay;
169 delay = date - usec_time;
180 struct timeval tv_date;
182 struct timeval tv_date, tv_delay;
184 mtime_t delay; /* delay in msec, signed to detect errors */
186 /* see mdate() about gettimeofday() possible errors */
187 gettimeofday( &tv_date, NULL );
189 /* calculate delay and check if current date is before wished date */
190 delay = date - (mtime_t) tv_date.tv_sec * 1000000
191 - (mtime_t) tv_date.tv_usec
194 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
195 * than to be late. */
196 if( delay <= 0 ) /* wished date is now or already passed */
204 tv_delay.tv_sec = delay / 1000000;
205 tv_delay.tv_usec = delay % 1000000;
207 /* see msleep() about select() errors */
208 select( 0, NULL, NULL, NULL, &tv_delay );
214 /*****************************************************************************
215 * msleep: more precise sleep() (inline function) (ok ?)
216 *****************************************************************************
217 * Portable usleep() function.
218 *****************************************************************************/
219 void msleep( mtime_t delay )
221 #if defined( HAVE_KERNEL_OS_H )
224 #elif defined( HAVE_USLEEP ) || defined( WIN32 )
228 struct timeval tv_delay;
230 tv_delay.tv_sec = delay / 1000000;
231 tv_delay.tv_usec = delay % 1000000;
232 /* select() return value should be tested, since several possible errors
233 * can occur. However, they should only happen in very particular occasions
234 * (i.e. when a signal is sent to the thread, or when memory is full), and
235 * can be ingnored. */
236 select( 0, NULL, NULL, NULL, &tv_delay );