| 1 | /* |
| 2 | * This file is part of DisOrder. |
| 3 | * Copyright (C) 2009 Richard Kettlewell |
| 4 | * |
| 5 | * This program is free software: you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation, either version 3 of the License, or |
| 8 | * (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | */ |
| 18 | /** @file lib/uaudio-alsa.c |
| 19 | * @brief Support for ALSA backend */ |
| 20 | #include "common.h" |
| 21 | |
| 22 | #if HAVE_ALSA_ASOUNDLIB_H |
| 23 | |
| 24 | #include <alsa/asoundlib.h> |
| 25 | |
| 26 | #include "mem.h" |
| 27 | #include "log.h" |
| 28 | #include "uaudio.h" |
| 29 | |
| 30 | /** @brief The current PCM handle */ |
| 31 | static snd_pcm_t *alsa_pcm; |
| 32 | |
| 33 | static const char *const alsa_options[] = { |
| 34 | "device", |
| 35 | NULL |
| 36 | }; |
| 37 | |
| 38 | /** @brief Actually play sound via ALSA */ |
| 39 | static size_t alsa_play(void *buffer, size_t samples) { |
| 40 | int err; |
| 41 | /* ALSA wants 'frames', where frame = several concurrently played samples */ |
| 42 | const snd_pcm_uframes_t frames = samples / uaudio_channels; |
| 43 | |
| 44 | snd_pcm_sframes_t rc = snd_pcm_writei(alsa_pcm, buffer, frames); |
| 45 | if(rc < 0) { |
| 46 | switch(rc) { |
| 47 | case -EPIPE: |
| 48 | if((err = snd_pcm_prepare(alsa_pcm))) |
| 49 | fatal(0, "error calling snd_pcm_prepare: %d", err); |
| 50 | return 0; |
| 51 | case -EAGAIN: |
| 52 | return 0; |
| 53 | default: |
| 54 | fatal(0, "error calling snd_pcm_writei: %d", (int)rc); |
| 55 | } |
| 56 | } |
| 57 | return rc * uaudio_channels; |
| 58 | } |
| 59 | |
| 60 | /** @brief Open the ALSA sound device */ |
| 61 | static void alsa_open(void) { |
| 62 | const char *device = uaudio_get("device"); |
| 63 | int err; |
| 64 | |
| 65 | if(!device || !*device) |
| 66 | device = "default"; |
| 67 | if((err = snd_pcm_open(&alsa_pcm, |
| 68 | device, |
| 69 | SND_PCM_STREAM_PLAYBACK, |
| 70 | 0))) |
| 71 | fatal(0, "error from snd_pcm_open: %d", err); |
| 72 | snd_pcm_hw_params_t *hwparams; |
| 73 | snd_pcm_hw_params_alloca(&hwparams); |
| 74 | if((err = snd_pcm_hw_params_any(alsa_pcm, hwparams)) < 0) |
| 75 | fatal(0, "error from snd_pcm_hw_params_any: %d", err); |
| 76 | if((err = snd_pcm_hw_params_set_access(alsa_pcm, hwparams, |
| 77 | SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) |
| 78 | fatal(0, "error from snd_pcm_hw_params_set_access: %d", err); |
| 79 | int sample_format; |
| 80 | if(uaudio_bits == 16) |
| 81 | sample_format = uaudio_signed ? SND_PCM_FORMAT_S16 : SND_PCM_FORMAT_U16; |
| 82 | else |
| 83 | sample_format = uaudio_signed ? SND_PCM_FORMAT_S8 : SND_PCM_FORMAT_U8; |
| 84 | if((err = snd_pcm_hw_params_set_format(alsa_pcm, hwparams, |
| 85 | sample_format)) < 0) |
| 86 | fatal(0, "error from snd_pcm_hw_params_set_format (%d): %d", |
| 87 | sample_format, err); |
| 88 | unsigned rate = uaudio_rate; |
| 89 | if((err = snd_pcm_hw_params_set_rate_near(alsa_pcm, hwparams, &rate, 0)) < 0) |
| 90 | fatal(0, "error from snd_pcm_hw_params_set_rate_near (%d): %d", |
| 91 | rate, err); |
| 92 | if((err = snd_pcm_hw_params_set_channels(alsa_pcm, hwparams, |
| 93 | uaudio_channels)) < 0) |
| 94 | fatal(0, "error from snd_pcm_hw_params_set_channels (%d): %d", |
| 95 | uaudio_channels, err); |
| 96 | if((err = snd_pcm_hw_params(alsa_pcm, hwparams)) < 0) |
| 97 | fatal(0, "error calling snd_pcm_hw_params: %d", err); |
| 98 | |
| 99 | } |
| 100 | |
| 101 | static void alsa_activate(void) { |
| 102 | uaudio_thread_activate(); |
| 103 | } |
| 104 | |
| 105 | static void alsa_deactivate(void) { |
| 106 | uaudio_thread_deactivate(); |
| 107 | } |
| 108 | |
| 109 | static void alsa_start(uaudio_callback *callback, |
| 110 | void *userdata) { |
| 111 | if(uaudio_channels != 1 && uaudio_channels != 2) |
| 112 | fatal(0, "asked for %d channels but only support 1 or 2", |
| 113 | uaudio_channels); |
| 114 | if(uaudio_bits != 8 && uaudio_bits != 16) |
| 115 | fatal(0, "asked for %d bits/channel but only support 8 or 16", |
| 116 | uaudio_bits); |
| 117 | alsa_open(); |
| 118 | uaudio_thread_start(callback, userdata, alsa_play, |
| 119 | 32 / uaudio_sample_size, |
| 120 | 4096 / uaudio_sample_size); |
| 121 | } |
| 122 | |
| 123 | static void alsa_stop(void) { |
| 124 | uaudio_thread_stop(); |
| 125 | snd_pcm_close(alsa_pcm); |
| 126 | alsa_pcm = 0; |
| 127 | } |
| 128 | |
| 129 | const struct uaudio uaudio_alsa = { |
| 130 | .name = "alsa", |
| 131 | .options = alsa_options, |
| 132 | .start = alsa_start, |
| 133 | .stop = alsa_stop, |
| 134 | .activate = alsa_activate, |
| 135 | .deactivate = alsa_deactivate |
| 136 | }; |
| 137 | |
| 138 | #endif |
| 139 | |
| 140 | /* |
| 141 | Local Variables: |
| 142 | c-basic-offset:2 |
| 143 | comment-column:40 |
| 144 | fill-column:79 |
| 145 | indent-tabs-mode:nil |
| 146 | End: |
| 147 | */ |