include/mtime.h

   1 /*****************************************************************************
   2  * mtime.h: high resolution time management functions
   3  * This header provides portable high precision time management functions,
   4  * which should be the only ones used in other segments of the program, since
   5  * functions like gettimeofday() and ftime() are not always supported.
   6  * Most functions are declared as inline or as macros since they are only
   7  * interfaces to system calls and have to be called frequently.
   8  * 'm' stands for 'micro', since maximum resolution is the microsecond.
   9  * Functions prototyped are implemented in interface/mtime.c.
  10  *****************************************************************************
  11  * Copyright (C) 1996, 1997, 1998, 1999, 2000 the VideoLAN team
  12  * $Id$
  13  *
  14  * Authors: Vincent Seguin <seguin@via.ecp.fr>
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  29  *****************************************************************************/
  30
  31 /*****************************************************************************
  32  * LAST_MDATE: date which will never happen
  33  *****************************************************************************
  34  * This date can be used as a 'never' date, to mark missing events in a function
  35  * supposed to return a date, such as nothing to display in a function
  36  * returning the date of the first image to be displayed. It can be used in
  37  * comparaison with other values: all existing dates will be earlier.
  38  *****************************************************************************/
  39 #define LAST_MDATE ((mtime_t)((uint64_t)(-1)/2))
  40
  41 /*****************************************************************************
  42  * MSTRTIME_MAX_SIZE: maximum possible size of mstrtime
  43  *****************************************************************************
  44  * This values is the maximal possible size of the string returned by the
  45  * mstrtime() function, including '-' and the final '\0'. It should be used to
  46  * allocate the buffer.
  47  *****************************************************************************/
  48 #define MSTRTIME_MAX_SIZE 22
  49
  50 /* Well, Duh? But it does clue us in that we are converting from
  51    millisecond quantity to a second quantity or vice versa.
  52 */
  53 #define MILLISECONDS_PER_SEC 1000
  54
  55 #define msecstotimestr(psz_buffer, msecs) \
  56   secstotimestr( psz_buffer, (msecs / (int) MILLISECONDS_PER_SEC) )
  57
  58 /*****************************************************************************
  59  * Prototypes
  60  *****************************************************************************/
  61 VLC_EXPORT( char *,  mstrtime, ( char *psz_buffer, mtime_t date ) );
  62 VLC_EXPORT( mtime_t, mdate,    ( void ) );
  63 VLC_EXPORT( void,    mwait,    ( mtime_t date ) );
  64 VLC_EXPORT( void,    msleep,   ( mtime_t delay ) );
  65 VLC_EXPORT( char *,  secstotimestr, ( char *psz_buffer, int secs ) );
  66
  67 /*****************************************************************************
  68  * date_t: date incrementation without long-term rounding errors
  69  *****************************************************************************/
  70 struct date_t
  71 {
  72     mtime_t  date;
  73     uint32_t i_divider_num;
  74     uint32_t i_divider_den;
  75     uint32_t i_remainder;
  76 };
  77
  78 VLC_EXPORT( void,    date_Init,      ( date_t *, uint32_t, uint32_t ) );
  79 VLC_EXPORT( void,    date_Change,    ( date_t *, uint32_t, uint32_t ) );
  80 VLC_EXPORT( void,    date_Set,       ( date_t *, mtime_t ) );
  81 VLC_EXPORT( mtime_t, date_Get,       ( const date_t * ) );
  82 VLC_EXPORT( void,    date_Move,      ( date_t *, mtime_t ) );
  83 VLC_EXPORT( mtime_t, date_Increment, ( date_t *, uint32_t ) );