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 1.17 2001/04/28 03:36:25 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() */
36 #include <unistd.h> /* select() */
39 #ifdef HAVE_KERNEL_OS_H
40 #include <kernel/OS.h>
51 /*****************************************************************************
52 * mstrtime: return a date in a readable format
53 *****************************************************************************
54 * This functions is provided for any interface function which need to print a
55 * date. psz_buffer should be a buffer long enough to store the formatted
57 *****************************************************************************/
58 char *mstrtime( char *psz_buffer, mtime_t date )
60 sprintf( psz_buffer, "%02d:%02d:%02d-%03d.%03d",
61 (int) (date / (1000LL * 1000LL * 60LL * 60LL) % 24LL),
62 (int) (date / (1000LL * 1000LL * 60LL) % 60LL),
63 (int) (date / (1000LL * 1000LL) % 60LL),
64 (int) (date / 1000LL % 1000LL),
65 (int) (date % 1000LL) );
69 /*****************************************************************************
70 * mdate: return high precision date (inline function)
71 *****************************************************************************
72 * Uses the gettimeofday() function when possible (1 MHz resolution) or the
73 * ftime() function (1 kHz resolution).
74 *****************************************************************************/
77 #if defined( HAVE_KERNEL_OS_H )
78 return( real_time_clock_usecs() );
80 #elif defined( WIN32 )
81 /* We don't get the real date, just the value of a high precision timer.
82 * this is because the usual time functions have at best only a milisecond
84 mtime_t freq,usec_time;
86 if( !QueryPerformanceFrequency((LARGE_INTEGER *)&freq) )
88 /* Milisecond resolution */
90 GetSystemTimeAsFileTime((FILETIME *)&file_time);
95 /* Microsecond resolution */
96 QueryPerformanceCounter((LARGE_INTEGER *)&usec_time);
97 usec_time /= (freq/1000000);
102 struct timeval tv_date;
104 /* gettimeofday() could return an error, and should be tested. However, the
105 * only possible error, according to 'man', is EFAULT, which can not happen
106 * here, since tv is a local variable. */
107 gettimeofday( &tv_date, NULL );
108 return( (mtime_t) tv_date.tv_sec * 1000000 + (mtime_t) tv_date.tv_usec );
113 /*****************************************************************************
114 * mwait: wait for a date (inline function)
115 *****************************************************************************
116 * This function uses select() and an system date function to wake up at a
117 * precise date. It should be used for process synchronization. If current date
118 * is posterior to wished date, the function returns immediately.
119 *****************************************************************************/
120 void mwait( mtime_t date )
122 #if defined( HAVE_KERNEL_OS_H )
125 delay = date - real_time_clock_usecs();
132 #elif defined( WIN32 )
133 mtime_t usec_time, delay;
136 delay = date - usec_time;
141 /* Sleep only has milisecond resolution */
142 Sleep( (DWORD)(delay/1000) );
147 struct timeval tv_date;
149 struct timeval tv_date, tv_delay;
151 mtime_t delay; /* delay in msec, signed to detect errors */
153 /* see mdate() about gettimeofday() possible errors */
154 gettimeofday( &tv_date, NULL );
156 /* calculate delay and check if current date is before wished date */
157 delay = date - (mtime_t) tv_date.tv_sec * 1000000 - (mtime_t) tv_date.tv_usec - 10000;
158 /* Linux/i386 has a granularity of 10 ms. It's better to be in advance
159 * than to be late. */
160 if( delay <= 0 ) /* wished date is now or already passed */
168 tv_delay.tv_sec = delay / 1000000;
169 tv_delay.tv_usec = delay % 1000000;
171 /* see msleep() about select() errors */
172 select( 0, NULL, NULL, NULL, &tv_delay );
178 /*****************************************************************************
179 * msleep: more precise sleep() (inline function) (ok ?)
180 *****************************************************************************
181 * Portable usleep() function.
182 *****************************************************************************/
183 void msleep( mtime_t delay )
185 #if defined( HAVE_KERNEL_OS_H )
188 #elif defined( WIN32 )
189 Sleep( delay/1000 ); /* Sleep only has milisecond resolution */
190 /* Maybe we could use the multimedia timer to reach the right resolution, */
191 /* or the old Winsock select() function ?*/
193 #elif defined( HAVE_USLEEP )
197 struct timeval tv_delay;
199 tv_delay.tv_sec = delay / 1000000;
200 tv_delay.tv_usec = delay % 1000000;
201 /* select() return value should be tested, since several possible errors
202 * can occur. However, they should only happen in very particular occasions
203 * (i.e. when a signal is sent to the thread, or when memory is full), and
204 * can be ingnored. */
205 select( 0, NULL, NULL, NULL, &tv_delay );