1 /*****************************************************************************
2 * vlc_mtime.h: high resolution time management functions
3 *****************************************************************************
4 * This header provides portable high precision time management functions,
5 * which should be the only ones used in other segments of the program, since
6 * functions like gettimeofday() and ftime() are not always supported.
7 * Most functions are declared as inline or as macros since they are only
8 * interfaces to system calls and have to be called frequently.
9 * 'm' stands for 'micro', since maximum resolution is the microsecond.
10 * Functions prototyped are implemented in interface/mtime.c.
11 *****************************************************************************
12 * Copyright (C) 1996, 1997, 1998, 1999, 2000 the VideoLAN team
15 * Authors: Vincent Seguin <seguin@via.ecp.fr>
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, write to the Free Software
29 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
30 *****************************************************************************/
33 # define __VLC_MTIME_H 1
35 /*****************************************************************************
36 * LAST_MDATE: date which will never happen
37 *****************************************************************************
38 * This date can be used as a 'never' date, to mark missing events in a function
39 * supposed to return a date, such as nothing to display in a function
40 * returning the date of the first image to be displayed. It can be used in
41 * comparaison with other values: all existing dates will be earlier.
42 *****************************************************************************/
43 #define LAST_MDATE ((mtime_t)((uint64_t)(-1)/2))
45 /*****************************************************************************
46 * MSTRTIME_MAX_SIZE: maximum possible size of mstrtime
47 *****************************************************************************
48 * This values is the maximal possible size of the string returned by the
49 * mstrtime() function, including '-' and the final '\0'. It should be used to
50 * allocate the buffer.
51 *****************************************************************************/
52 #define MSTRTIME_MAX_SIZE 22
54 /* Well, Duh? But it does clue us in that we are converting from
55 millisecond quantity to a second quantity or vice versa.
57 #define MILLISECONDS_PER_SEC 1000
59 #define msecstotimestr(psz_buffer, msecs) \
60 secstotimestr( psz_buffer, (msecs / (int) MILLISECONDS_PER_SEC) )
62 /*****************************************************************************
64 *****************************************************************************/
65 VLC_EXPORT( char *, mstrtime
, ( char *psz_buffer
, mtime_t date
) );
66 VLC_EXPORT( mtime_t
, mdate
, ( void ) );
67 VLC_EXPORT( void, mwait
, ( mtime_t date
) );
68 VLC_EXPORT( void, msleep
, ( mtime_t delay
) );
69 VLC_EXPORT( char *, secstotimestr
, ( char *psz_buffer
, int secs
) );
71 #if (defined (__GNUC__) && defined (__linux__)) || defined (__FreeBSD__) || defined (__OpenBSD__)
72 /* Linux has 100, 250, 300 or 1000Hz
74 * HZ=100 by default on FreeBSD, but some architectures use a 1000Hz timer
76 # define VLC_HARD_MIN_SLEEP 10000 /* 10 milliseconds = 1 tick at 100Hz */
77 # define VLC_SOFT_MIN_SLEEP 9000000 /* 9 seconds */
80 __attribute__((unused
))
81 __attribute__((noinline
))
82 __attribute__((error("sorry, cannot sleep for such short a time")))
83 mtime_t
impossible_delay( mtime_t delay
)
86 return VLC_HARD_MIN_SLEEP
;
90 __attribute__((unused
))
91 __attribute__((noinline
))
92 __attribute__((warning("use proper event handling instead of short delay")))
93 mtime_t
harmful_delay( mtime_t delay
)
98 # define check_delay( d ) \
99 ((__builtin_constant_p(d < VLC_HARD_MIN_SLEEP) \
100 && (d < VLC_HARD_MIN_SLEEP)) \
101 ? impossible_delay(d) \
102 : ((__builtin_constant_p(d < VLC_SOFT_MIN_SLEEP) \
103 && (d < VLC_SOFT_MIN_SLEEP)) \
108 __attribute__((unused
))
109 __attribute__((noinline
))
110 __attribute__((error("deadlines can not be constant")))
111 mtime_t
impossible_deadline( mtime_t deadline
)
116 # define check_deadline( d ) \
117 (__builtin_constant_p(d) ? impossible_deadline(d) : d)
119 # define check_delay(d) (d)
120 # define check_deadline(d) (d)
123 #define msleep(d) msleep(check_delay(d))
124 #define mwait(d) mwait(check_deadline(d))
126 /*****************************************************************************
127 * date_t: date incrementation without long-term rounding errors
128 *****************************************************************************/
132 uint32_t i_divider_num
;
133 uint32_t i_divider_den
;
134 uint32_t i_remainder
;
137 VLC_EXPORT( void, date_Init
, ( date_t
*, uint32_t, uint32_t ) );
138 VLC_EXPORT( void, date_Change
, ( date_t
*, uint32_t, uint32_t ) );
139 VLC_EXPORT( void, date_Set
, ( date_t
*, mtime_t
) );
140 VLC_EXPORT( mtime_t
, date_Get
, ( const date_t
* ) );
141 VLC_EXPORT( void, date_Move
, ( date_t
*, mtime_t
) );
142 VLC_EXPORT( mtime_t
, date_Increment
, ( date_t
*, uint32_t ) );
143 VLC_EXPORT( mtime_t
, date_Decrement
, ( date_t
*, uint32_t ) );
144 VLC_EXPORT( uint64_t, NTPtime64
, ( void ) );
145 #endif /* !__VLC_MTIME_ */