sys/dev/sound/pcm/feeder_volume.c

   1 /*-
   2  * Copyright (c) 2005 Ariff Abdullah <ariff@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/dev/sound/pcm/feeder_volume.c,v 1.2.2.1 2005/12/30 19:55:54 netchild Exp $
  27  * $DragonFly: src/sys/dev/sound/pcm/feeder_volume.c,v 1.1 2007/01/04 21:47:03 corecode Exp $
  28  *
  29  *
  30  * feeder_volume, a long 'Lost Technology' rather than a new feature.
  31  */
  32
  33 #include <dev/sound/pcm/sound.h>
  34 #include "feeder_if.h"
  35
  36 SND_DECLARE_FILE("$DragonFly: src/sys/dev/sound/pcm/feeder_volume.c,v 1.1 2007/01/04 21:47:03 corecode Exp $");
  37
  38 static int
  39 feed_volume_s16(struct pcm_feeder *f, struct pcm_channel *c, uint8_t *b,
  40                 uint32_t count, void *source)
  41 {
  42         int i, j, k, vol[2];
  43         int16_t *buf;
  44
  45         k = FEEDER_FEED(f->source, c, b, count & ~1, source);
  46         if (k < 2) {
  47 #if 0
  48                 device_printf(c->dev, "%s: Not enough data (Got: %d bytes)\n",
  49                                 __func__, k);
  50 #endif
  51                 return 0;
  52         }
  53 #if 0
  54         if (k & 1)
  55                 device_printf(c->dev, "%s: Bytes not 16bit aligned.\n", __func__);
  56 #endif
  57         k &= ~1;
  58         i = k >> 1;
  59         buf = (int16_t *)b;
  60         vol[0] = c->volume & 0x7f;
  61         vol[1] = (c->volume >> 8) & 0x7f;
  62         while (i > 0) {
  63                 i--;
  64                 j = (vol[i & 1] * buf[i]) / 100;
  65                 if (j > 32767)
  66                         j = 32767;
  67                 if (j < -32768)
  68                         j = -32768;
  69                 buf[i] = j;
  70         }
  71         return k;
  72 }
  73
  74 static struct pcm_feederdesc feeder_volume_s16_desc[] = {
  75         {FEEDER_VOLUME, AFMT_S16_LE|AFMT_STEREO, AFMT_S16_LE|AFMT_STEREO, 0},
  76         {0, 0, 0, 0},
  77 };
  78 static kobj_method_t feeder_volume_s16_methods[] = {
  79         KOBJMETHOD(feeder_feed, feed_volume_s16),
  80         {0, 0}
  81 };
  82 FEEDER_DECLARE(feeder_volume_s16, 2, NULL);