audio/noaudio.c

   1 /*
   2  * QEMU NULL audio output driver
   3  *
   4  * Copyright (c) 2004 Vassili Karpov (malc)
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "vl.h"
  25
  26 #include "audio/audio_int.h"
  27
  28 typedef struct NoVoice {
  29     HWVoice hw;
  30     int64_t old_ticks;
  31 } NoVoice;
  32
  33 #define dolog(...) AUD_log ("noaudio", __VA_ARGS__)
  34 #ifdef DEBUG
  35 #define ldebug(...) dolog (__VA_ARGS__)
  36 #else
  37 #define ldebug(...)
  38 #endif
  39
  40 static void no_hw_run (HWVoice *hw)
  41 {
  42     NoVoice *no = (NoVoice *) hw;
  43     int rpos, live, decr, samples;
  44     st_sample_t *src;
  45     int64_t now = qemu_get_clock (vm_clock);
  46     int64_t ticks = now - no->old_ticks;
  47     int64_t bytes = (ticks * hw->bytes_per_second) / ticks_per_sec;
  48
  49     if (bytes > INT_MAX)
  50         samples = INT_MAX >> hw->shift;
  51     else
  52         samples = bytes >> hw->shift;
  53
  54     live = pcm_hw_get_live (hw);
  55     if (live <= 0)
  56         return;
  57
  58     no->old_ticks = now;
  59     decr = audio_MIN (live, samples);
  60     samples = decr;
  61     rpos = hw->rpos;
  62     while (samples) {
  63         int left_till_end_samples = hw->samples - rpos;
  64         int convert_samples = audio_MIN (samples, left_till_end_samples);
  65
  66         src = advance (hw->mix_buf, rpos * sizeof (st_sample_t));
  67         memset (src, 0, convert_samples * sizeof (st_sample_t));
  68
  69         rpos = (rpos + convert_samples) % hw->samples;
  70         samples -= convert_samples;
  71     }
  72
  73     pcm_hw_dec_live (hw, decr);
  74     hw->rpos = rpos;
  75 }
  76
  77 static int no_hw_write (SWVoice *sw, void *buf, int len)
  78 {
  79     return pcm_hw_write (sw, buf, len);
  80 }
  81
  82 static int no_hw_init (HWVoice *hw, int freq, int nchannels, audfmt_e fmt)
  83 {
  84     hw->freq = freq;
  85     hw->nchannels = nchannels;
  86     hw->fmt = fmt;
  87     hw->bufsize = 4096;
  88     return 0;
  89 }
  90
  91 static void no_hw_fini (HWVoice *hw)
  92 {
  93     (void) hw;
  94 }
  95
  96 static int no_hw_ctl (HWVoice *hw, int cmd, ...)
  97 {
  98     (void) hw;
  99     (void) cmd;
 100     return 0;
 101 }
 102
 103 static void *no_audio_init (void)
 104 {
 105     return &no_audio_init;
 106 }
 107
 108 static void no_audio_fini (void *opaque)
 109 {
 110 }
 111
 112 struct pcm_ops no_pcm_ops = {
 113     no_hw_init,
 114     no_hw_fini,
 115     no_hw_run,
 116     no_hw_write,
 117     no_hw_ctl
 118 };
 119
 120 struct audio_output_driver no_output_driver = {
 121     "none",
 122     no_audio_init,
 123     no_audio_fini,
 124     &no_pcm_ops,
 125     1,
 126     1,
 127     sizeof (NoVoice)
 128 };