include/vlc_mtime.h

   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
  13  * $Id$
  14  *
  15  * Authors: Vincent Seguin <seguin@via.ecp.fr>
  16  *
  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.
  21  *
  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.
  26  *
  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  *****************************************************************************/
  31
  32 /*****************************************************************************
  33  * LAST_MDATE: date which will never happen
  34  *****************************************************************************
  35  * This date can be used as a 'never' date, to mark missing events in a function
  36  * supposed to return a date, such as nothing to display in a function
  37  * returning the date of the first image to be displayed. It can be used in
  38  * comparaison with other values: all existing dates will be earlier.
  39  *****************************************************************************/
  40 #define LAST_MDATE ((mtime_t)((uint64_t)(-1)/2))
  41
  42 /*****************************************************************************
  43  * MSTRTIME_MAX_SIZE: maximum possible size of mstrtime
  44  *****************************************************************************
  45  * This values is the maximal possible size of the string returned by the
  46  * mstrtime() function, including '-' and the final '\0'. It should be used to
  47  * allocate the buffer.
  48  *****************************************************************************/
  49 #define MSTRTIME_MAX_SIZE 22
  50
  51 /* Well, Duh? But it does clue us in that we are converting from
  52    millisecond quantity to a second quantity or vice versa.
  53 */
  54 #define MILLISECONDS_PER_SEC 1000
  55
  56 #define msecstotimestr(psz_buffer, msecs) \
  57   secstotimestr( psz_buffer, (msecs / (int) MILLISECONDS_PER_SEC) )
  58
  59 /*****************************************************************************
  60  * Prototypes
  61  *****************************************************************************/
  62 VLC_EXPORT( char *,  mstrtime, ( char *psz_buffer, mtime_t date ) );
  63 VLC_EXPORT( mtime_t, mdate,    ( void ) );
  64 VLC_EXPORT( void,    mwait,    ( mtime_t date ) );
  65 VLC_EXPORT( void,    msleep,   ( mtime_t delay ) );
  66 VLC_EXPORT( char *,  secstotimestr, ( char *psz_buffer, int secs ) );
  67
  68 /*****************************************************************************
  69  * date_t: date incrementation without long-term rounding errors
  70  *****************************************************************************/
  71 struct date_t
  72 {
  73     mtime_t  date;
  74     uint32_t i_divider_num;
  75     uint32_t i_divider_den;
  76     uint32_t i_remainder;
  77 };
  78
  79 VLC_EXPORT( void,    date_Init,      ( date_t *, uint32_t, uint32_t ) );
  80 VLC_EXPORT( void,    date_Change,    ( date_t *, uint32_t, uint32_t ) );
  81 VLC_EXPORT( void,    date_Set,       ( date_t *, mtime_t ) );
  82 VLC_EXPORT( mtime_t, date_Get,       ( const date_t * ) );
  83 VLC_EXPORT( void,    date_Move,      ( date_t *, mtime_t ) );
  84 VLC_EXPORT( mtime_t, date_Increment, ( date_t *, uint32_t ) );
  85 VLC_EXPORT( uint64_t, NTPtime64,     ( void ) );