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  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #include "plugin.h"
  24 #include "mpegplayer.h"
  25
  26 /** Streams **/
  27
  28 /* Initializes the cursor */
  29 void stream_scan_init(struct stream_scan *sk)
  30 {
  31     dbuf_l2_init(&sk->l2);
  32 }
  33
  34 /* Ensures direction is -1 or 1 and margin is properly initialized */
  35 void stream_scan_normalize(struct stream_scan *sk)
  36 {
  37     if (sk->dir >= 0)
  38     {
  39         sk->dir = SSCAN_FORWARD;
  40         sk->margin = sk->len;
  41     }
  42     else if (sk->dir < 0)
  43     {
  44         sk->dir = SSCAN_REVERSE;
  45         sk->margin = 0;
  46     }
  47 }
  48
  49 /* Moves a scan cursor. If amount is positive, the increment is in the scan
  50  * direction, otherwise opposite the scan direction */
  51 void stream_scan_offset(struct stream_scan *sk, off_t by)
  52 {
  53     off_t bydir = by*sk->dir;
  54     sk->pos += bydir;
  55     sk->margin -= bydir;
  56     sk->len -= by;
  57 }
  58
  59 /** Time helpers **/
  60 void ts_to_hms(uint32_t pts, struct hms *hms)
  61 {
  62     hms->frac = pts % TS_SECOND;
  63     hms->sec = pts / TS_SECOND;
  64     hms->min = hms->sec / 60;
  65     hms->hrs = hms->min / 60;
  66     hms->sec %= 60;
  67     hms->min %= 60;
  68 }
  69
  70 void hms_format(char *buf, size_t bufsize, struct hms *hms)
  71 {
  72     /* Only display hours if nonzero */
  73     if (hms->hrs != 0)
  74     {
  75         rb->snprintf(buf, bufsize, "%u:%02u:%02u",
  76                      hms->hrs, hms->min, hms->sec);
  77     }
  78     else
  79     {
  80         rb->snprintf(buf, bufsize, "%u:%02u",
  81                      hms->min, hms->sec);
  82     }
  83 }
  84
  85 /** Maths **/
  86 uint32_t muldiv_uint32(uint32_t multiplicand,
  87                        uint32_t multiplier,
  88                        uint32_t divisor)
  89 {
  90     if (divisor != 0)
  91     {
  92         uint64_t prod = (uint64_t)multiplier*multiplicand + divisor/2;
  93
  94         if ((uint32_t)(prod >> 32) < divisor)
  95             return (uint32_t)(prod / divisor);
  96     }
  97     else if (multiplicand == 0 || multiplier == 0)
  98     {
  99         return 0; /* 0/0 = 0 : yaya */
 100     }
 101     /* else (> 0) / 0 = UINT32_MAX */
 102
 103     return UINT32_MAX; /* Saturate */
 104 }