apps/plugins/mpegplayer/mpeg_misc.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Miscellaneous helper API definitions
  11  *
  12  * Copyright (c) 2007 Michael Sevakis
  13  *
  14  * All files in this archive are subject to the GNU General Public License.
  15  * See the file COPYING in the source tree root for full license agreement.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include "plugin.h"
  22 #include "mpegplayer.h"
  23
  24 /** Streams **/
  25
  26 /* Ensures direction is -1 or 1 and margin is properly initialized */
  27 void stream_scan_normalize(struct stream_scan *sk)
  28 {
  29     if (sk->dir >= 0)
  30     {
  31         sk->dir = SSCAN_FORWARD;
  32         sk->margin = sk->len;
  33     }
  34     else if (sk->dir < 0)
  35     {
  36         sk->dir = SSCAN_REVERSE;
  37         sk->margin = 0;
  38     }
  39 }
  40
  41 /* Moves a scan cursor. If amount is positive, the increment is in the scan
  42  * direction, otherwise opposite the scan direction */
  43 void stream_scan_offset(struct stream_scan *sk, off_t by)
  44 {
  45     off_t bydir = by*sk->dir;
  46     sk->pos += bydir;
  47     sk->margin -= bydir;
  48     sk->len -= by;
  49 }
  50
  51 /** Time helpers **/
  52 void ts_to_hms(uint32_t pts, struct hms *hms)
  53 {
  54     hms->frac = pts % TS_SECOND;
  55     hms->sec = pts / TS_SECOND;
  56     hms->min = hms->sec / 60;
  57     hms->hrs = hms->min / 60;
  58     hms->sec %= 60;
  59     hms->min %= 60;
  60 }
  61
  62 void hms_format(char *buf, size_t bufsize, struct hms *hms)
  63 {
  64     /* Only display hours if nonzero */
  65     if (hms->hrs != 0)
  66     {
  67         rb->snprintf(buf, bufsize, "%u:%02u:%02u",
  68                      hms->hrs, hms->min, hms->sec);
  69     }
  70     else
  71     {
  72         rb->snprintf(buf, bufsize, "%u:%02u",
  73                      hms->min, hms->sec);
  74     }
  75 }
  76
  77 /** Maths **/
  78 uint32_t muldiv_uint32(uint32_t multiplicand,
  79                        uint32_t multiplier,
  80                        uint32_t divisor)
  81 {
  82     if (divisor != 0)
  83     {
  84         uint64_t prod = (uint64_t)multiplier*multiplicand + divisor/2;
  85
  86         if ((uint32_t)(prod >> 32) < divisor)
  87             return (uint32_t)(prod / divisor);
  88     }
  89     else if (multiplicand == 0 || multiplier == 0)
  90     {
  91         return 0; /* 0/0 = 0 : yaya */
  92     }
  93     /* else (> 0) / 0 = UINT32_MAX */
  94
  95     return UINT32_MAX; /* Saturate */
  96 }