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     uint8_t *dst;
  45     st_sample_t *src;
  46     int64_t now = qemu_get_clock (vm_clock);
  47     int64_t ticks = now - no->old_ticks;
  48     int64_t bytes = (ticks * hw->bytes_per_second) / ticks_per_sec;
  49
  50     if (bytes > INT_MAX)
  51         samples = INT_MAX >> hw->shift;
  52     else
  53         samples = bytes >> hw->shift;
  54
  55     live = pcm_hw_get_live (hw);
  56     if (live <= 0)
  57         return;
  58
  59     no->old_ticks = now;
  60     decr = audio_MIN (live, samples);
  61     samples = decr;
  62     rpos = hw->rpos;
  63     while (samples) {
  64         int left_till_end_samples = hw->samples - rpos;
  65         int convert_samples = audio_MIN (samples, left_till_end_samples);
  66
  67         src = advance (hw->mix_buf, rpos * sizeof (st_sample_t));
  68         memset (src, 0, convert_samples * sizeof (st_sample_t));
  69
  70         rpos = (rpos + convert_samples) % hw->samples;
  71         samples -= convert_samples;
  72     }
  73
  74     pcm_hw_dec_live (hw, decr);
  75     hw->rpos = rpos;
  76 }
  77
  78 static int no_hw_write (SWVoice *sw, void *buf, int len)
  79 {
  80     return pcm_hw_write (sw, buf, len);
  81 }
  82
  83 static int no_hw_init (HWVoice *hw, int freq, int nchannels, audfmt_e fmt)
  84 {
  85     NoVoice *no = (NoVoice *) hw;
  86     hw->freq = freq;
  87     hw->nchannels = nchannels;
  88     hw->fmt = fmt;
  89     hw->bufsize = 4096;
  90     return 0;
  91 }
  92
  93 static void no_hw_fini (HWVoice *hw)
  94 {
  95     (void) hw;
  96 }
  97
  98 static int no_hw_ctl (HWVoice *hw, int cmd, ...)
  99 {
 100     (void) hw;
 101     (void) cmd;
 102     return 0;
 103 }
 104
 105 static void *no_audio_init (void)
 106 {
 107     return &no_audio_init;
 108 }
 109
 110 static void no_audio_fini (void *opaque)
 111 {
 112 }
 113
 114 struct pcm_ops no_pcm_ops = {
 115     no_hw_init,
 116     no_hw_fini,
 117     no_hw_run,
 118     no_hw_write,
 119     no_hw_ctl
 120 };
 121
 122 struct audio_output_driver no_output_driver = {
 123     "none",
 124     no_audio_init,
 125     no_audio_fini,
 126     &no_pcm_ops,
 127     1,
 128     1,
 129     sizeof (NoVoice)
 130 };