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Annotation of qemu/audio/noaudio.c, revision 1.1.1.1

1.1       root        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: };

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