sound/rate.h

   1 /* ScummVM - Graphic Adventure Engine
   2  *
   3  * ScummVM is the legal property of its developers, whose names
   4  * are too numerous to list here. Please refer to the COPYRIGHT
   5  * file distributed with this source distribution.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  *
  21  * $URL$
  22  * $Id$
  23  *
  24  */
  25
  26 #ifndef SOUND_RATE_H
  27 #define SOUND_RATE_H
  28
  29 #include "common/scummsys.h"
  30 #include "engines/engine.h"
  31
  32 class AudioStream;
  33
  34
  35 namespace Audio {
  36
  37 typedef int16 st_sample_t;
  38 typedef uint16 st_volume_t;
  39 typedef uint32 st_size_t;
  40 typedef uint32 st_rate_t;
  41
  42 /* Minimum and maximum values a sample can hold. */
  43 enum {
  44         ST_SAMPLE_MAX = 0x7fffL,
  45         ST_SAMPLE_MIN = (-ST_SAMPLE_MAX - 1L)
  46 };
  47
  48 enum {
  49         ST_EOF = -1,
  50         ST_SUCCESS = 0
  51 };
  52
  53 static inline void clampedAdd(int16& a, int b) {
  54         register int val;
  55 #ifdef OUTPUT_UNSIGNED_AUDIO
  56         val = (a ^ 0x8000) + b;
  57 #else
  58         val = a + b;
  59 #endif
  60
  61         if (val > ST_SAMPLE_MAX)
  62                 val = ST_SAMPLE_MAX;
  63         else if (val < ST_SAMPLE_MIN)
  64                 val = ST_SAMPLE_MIN;
  65
  66 #ifdef OUTPUT_UNSIGNED_AUDIO
  67         a = ((int16)val) ^ 0x8000;
  68 #else
  69         a = val;
  70 #endif
  71 }
  72
  73 class RateConverter {
  74 public:
  75         RateConverter() {}
  76         virtual ~RateConverter() {}
  77         virtual int flow(AudioStream &input, st_sample_t *obuf, st_size_t osamp, st_volume_t vol_l, st_volume_t vol_r) = 0;
  78         virtual int drain(st_sample_t *obuf, st_size_t osamp, st_volume_t vol) = 0;
  79 };
  80
  81 RateConverter *makeRateConverter(st_rate_t inrate, st_rate_t outrate, bool stereo, bool reverseStereo = false);
  82
  83 } // End of namespace Audio
  84
  85 #endif