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https://code.videolan.org/videolan/vlc
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148 lines
5.8 KiB
C
148 lines
5.8 KiB
C
/*****************************************************************************
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* vlc_mtime.h: high resolution time management functions
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*****************************************************************************
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* This header provides portable high precision time management functions,
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* which should be the only ones used in other segments of the program, since
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* functions like gettimeofday() and ftime() are not always supported.
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* Most functions are declared as inline or as macros since they are only
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* interfaces to system calls and have to be called frequently.
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* 'm' stands for 'micro', since maximum resolution is the microsecond.
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* Functions prototyped are implemented in interface/mtime.c.
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*****************************************************************************
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* Copyright (C) 1996, 1997, 1998, 1999, 2000 the VideoLAN team
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* $Id$
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*
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* Authors: Vincent Seguin <seguin@via.ecp.fr>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifndef __VLC_MTIME_H
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# define __VLC_MTIME_H 1
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/*****************************************************************************
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* LAST_MDATE: date which will never happen
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*****************************************************************************
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* This date can be used as a 'never' date, to mark missing events in a function
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* supposed to return a date, such as nothing to display in a function
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* returning the date of the first image to be displayed. It can be used in
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* comparaison with other values: all existing dates will be earlier.
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*****************************************************************************/
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#define LAST_MDATE ((mtime_t)((uint64_t)(-1)/2))
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/*****************************************************************************
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* MSTRTIME_MAX_SIZE: maximum possible size of mstrtime
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*****************************************************************************
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* This values is the maximal possible size of the string returned by the
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* mstrtime() function, including '-' and the final '\0'. It should be used to
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* allocate the buffer.
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*****************************************************************************/
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#define MSTRTIME_MAX_SIZE 22
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/* Well, Duh? But it does clue us in that we are converting from
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millisecond quantity to a second quantity or vice versa.
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*/
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#define MILLISECONDS_PER_SEC 1000
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#define msecstotimestr(psz_buffer, msecs) \
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secstotimestr( psz_buffer, (msecs / (int) MILLISECONDS_PER_SEC) )
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/*****************************************************************************
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* Prototypes
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*****************************************************************************/
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VLC_EXPORT( char *, mstrtime, ( char *psz_buffer, mtime_t date ) );
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VLC_EXPORT( mtime_t, mdate, ( void ) );
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VLC_EXPORT( void, mwait, ( mtime_t date ) );
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VLC_EXPORT( void, msleep, ( mtime_t delay ) );
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VLC_EXPORT( char *, secstotimestr, ( char *psz_buffer, int secs ) );
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# define VLC_HARD_MIN_SLEEP 10000 /* 10 milliseconds = 1 tick at 100Hz */
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#if defined (__GNUC__) \
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&& ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
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/* Linux has 100, 250, 300 or 1000Hz
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*
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* HZ=100 by default on FreeBSD, but some architectures use a 1000Hz timer
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*/
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# define VLC_SOFT_MIN_SLEEP 9000000 /* 9 seconds */
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static
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__attribute__((unused))
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__attribute__((noinline))
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__attribute__((error("sorry, cannot sleep for such short a time")))
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mtime_t impossible_delay( mtime_t delay )
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{
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(void) delay;
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return VLC_HARD_MIN_SLEEP;
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}
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static
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__attribute__((unused))
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__attribute__((noinline))
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__attribute__((warning("use proper event handling instead of short delay")))
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mtime_t harmful_delay( mtime_t delay )
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{
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return delay;
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}
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# define check_delay( d ) \
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((__builtin_constant_p(d < VLC_HARD_MIN_SLEEP) \
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&& (d < VLC_HARD_MIN_SLEEP)) \
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? impossible_delay(d) \
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: ((__builtin_constant_p(d < VLC_SOFT_MIN_SLEEP) \
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&& (d < VLC_SOFT_MIN_SLEEP)) \
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? harmful_delay(d) \
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: d))
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static
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__attribute__((unused))
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__attribute__((noinline))
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__attribute__((error("deadlines can not be constant")))
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mtime_t impossible_deadline( mtime_t deadline )
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{
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return deadline;
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}
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# define check_deadline( d ) \
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(__builtin_constant_p(d) ? impossible_deadline(d) : d)
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#else
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# define check_delay(d) (d)
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# define check_deadline(d) (d)
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#endif
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#define msleep(d) msleep(check_delay(d))
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#define mwait(d) mwait(check_deadline(d))
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/*****************************************************************************
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* date_t: date incrementation without long-term rounding errors
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*****************************************************************************/
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struct date_t
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{
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mtime_t date;
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uint32_t i_divider_num;
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uint32_t i_divider_den;
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uint32_t i_remainder;
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};
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VLC_EXPORT( void, date_Init, ( date_t *, uint32_t, uint32_t ) );
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VLC_EXPORT( void, date_Change, ( date_t *, uint32_t, uint32_t ) );
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VLC_EXPORT( void, date_Set, ( date_t *, mtime_t ) );
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VLC_EXPORT( mtime_t, date_Get, ( const date_t * ) );
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VLC_EXPORT( void, date_Move, ( date_t *, mtime_t ) );
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VLC_EXPORT( mtime_t, date_Increment, ( date_t *, uint32_t ) );
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VLC_EXPORT( mtime_t, date_Decrement, ( date_t *, uint32_t ) );
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VLC_EXPORT( uint64_t, NTPtime64, ( void ) );
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#endif /* !__VLC_MTIME_ */
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