/*

alsa: sound output with Advanced Linux Sound Architecture 1.x API

copyright 2006-2016 by the mpg123 project - free software under the terms of the LGPL 2.1

see COPYING and AUTHORS files in distribution or http://mpg123.org

initially written by Clemens Ladisch <clemens@ladisch.de>

*/

/* ALSA headers define struct timeval if no POSIX macro is set,

nicely in conflict with definitions in system headers. They had

a discussion about that a long time ago:

http://mailman.alsa-project.org/pipermail/alsa-devel/2007-June/001684.html

... seems like the conclusion was not carried through.

*/

#define _POSIX_SOURCE

/* Things are still missing if _DEFAULT_SOURCE is not defined (for recent

glibc, I presume. */

#define _DEFAULT_SOURCE

#include "out123_int.h"

#include <errno.h>

/* make ALSA 0.9.x compatible to the 1.0.x API */

#define ALSA_PCM_NEW_HW_PARAMS_API

#define ALSA_PCM_NEW_SW_PARAMS_API

#include <alloca.h> /* GCC complains about missing declaration of alloca. */

#include <alsa/asoundlib.h>

#include "debug.h"

/* Total buffer size in seconds, 0.2 is more true to what ALSA maximally uses

here (8192 samples). The earlier default of 0.5 was never true. */

#define BUFFER_LENGTH (ao->device_buffer > 0. ? ao->device_buffer : 0.2)

static const struct {

snd_pcm_format_t alsa;

int mpg123;

} format_map[] = {

{ SND_PCM_FORMAT_S16, MPG123_ENC_SIGNED_16 },

{ SND_PCM_FORMAT_U16, MPG123_ENC_UNSIGNED_16 },

{ SND_PCM_FORMAT_U8, MPG123_ENC_UNSIGNED_8 },

{ SND_PCM_FORMAT_S8, MPG123_ENC_SIGNED_8 },

{ SND_PCM_FORMAT_A_LAW, MPG123_ENC_ALAW_8 },

{ SND_PCM_FORMAT_MU_LAW, MPG123_ENC_ULAW_8 },

{ SND_PCM_FORMAT_S32, MPG123_ENC_SIGNED_32 },

{ SND_PCM_FORMAT_U32, MPG123_ENC_UNSIGNED_32 },

#ifdef WORDS_BIGENDIAN

{ SND_PCM_FORMAT_S24_3BE, MPG123_ENC_SIGNED_24 },

{ SND_PCM_FORMAT_U24_3BE, MPG123_ENC_UNSIGNED_24 },

#else

{ SND_PCM_FORMAT_S24_3LE, MPG123_ENC_SIGNED_24 },

{ SND_PCM_FORMAT_U24_3LE, MPG123_ENC_UNSIGNED_24 },

#endif

{ SND_PCM_FORMAT_FLOAT, MPG123_ENC_FLOAT_32 },

{ SND_PCM_FORMAT_FLOAT64, MPG123_ENC_FLOAT_64 }

};

#define NUM_FORMATS (sizeof format_map / sizeof format_map[0])

static int rates_match(long int desired, unsigned int actual)

{

return actual * 100 > desired * (100 - AUDIO_RATE_TOLERANCE) &&

actual * 100 < desired * (100 + AUDIO_RATE_TOLERANCE);

}

static int initialize_device(out123_handle *ao)

{

snd_pcm_hw_params_t *hw=NULL;

snd_pcm_sw_params_t *sw=NULL;

snd_pcm_uframes_t buffer_size;

snd_pcm_uframes_t period_size;

snd_pcm_format_t format;

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

unsigned int rate;

int i;

snd_pcm_hw_params_alloca(&hw); /* Ignore GCC warning here... alsa-lib>=1.0.16 doesn't trigger that anymore, too. */

if (snd_pcm_hw_params_any(pcm, hw) < 0) {

if(!AOQUIET) error("initialize_device(): no configuration available");

return -1;

}

if (snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {

if(!AOQUIET) error("initialize_device(): device does not support interleaved access");

return -1;

}

format = SND_PCM_FORMAT_UNKNOWN;

for (i = 0; i < NUM_FORMATS; ++i) {

if (ao->format == format_map[i].mpg123) {

format = format_map[i].alsa;

break;

}

}

if (format == SND_PCM_FORMAT_UNKNOWN) {

if(!AOQUIET) error1("initialize_device(): invalid sample format %d", ao->format);

errno = EINVAL;

return -1;

}

if (snd_pcm_hw_params_set_format(pcm, hw, format) < 0) {

if(!AOQUIET) error1("initialize_device(): cannot set format %s", snd_pcm_format_name(format));

return -1;

}

if (snd_pcm_hw_params_set_channels(pcm, hw, ao->channels) < 0) {

if(!AOQUIET) error1("initialize_device(): cannot set %d channels", ao->channels);

return -1;

}

rate = ao->rate;

if (snd_pcm_hw_params_set_rate_near(pcm, hw, &rate, NULL) < 0) {

if(!AOQUIET) error1("initialize_device(): cannot set rate %u", rate);

return -1;

}

if (!rates_match(ao->rate, rate)) {

if(!AOQUIET) error2("initialize_device(): rate %ld not available, using %u", ao->rate, rate);

/* return -1; */

}

buffer_size = rate * BUFFER_LENGTH;

if (snd_pcm_hw_params_set_buffer_size_near(pcm, hw, &buffer_size) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set buffer size");

return -1;

}

debug1("buffer_size=%lu", (unsigned long)buffer_size);

period_size = buffer_size / 3; /* 3 periods is so much more common. */

if (snd_pcm_hw_params_set_period_size_near(pcm, hw, &period_size, NULL) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set period size");

return -1;

}

debug1("period_size=%lu", (unsigned long)period_size);

if (snd_pcm_hw_params(pcm, hw) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set hw params");

return -1;

}

snd_pcm_sw_params_alloca(&sw);

if (snd_pcm_sw_params_current(pcm, sw) < 0) {

if(!AOQUIET) error("initialize_device(): cannot get sw params");

return -1;

}

/* start playing right away */

if (snd_pcm_sw_params_set_start_threshold(pcm, sw, 1) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set start threshold");

return -1;

}

/* wake up on every interrupt */

if (snd_pcm_sw_params_set_avail_min(pcm, sw, 1) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set min available");

return -1;

}

#if SND_LIB_VERSION < ((1<<16)|16)

/* Always write as many frames as possible (deprecated since alsa-lib 1.0.16) */

if (snd_pcm_sw_params_set_xfer_align(pcm, sw, 1) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set transfer alignment");

return -1;

}

#endif

if (snd_pcm_sw_params(pcm, sw) < 0) {

if(!AOQUIET) error("initialize_device(): cannot set sw params");

return -1;

}

return 0;

}

#ifndef DEBUG

static void error_ignorer(const char *file, int line, const char *function, int err, const char *fmt,...)

{

/* I can make ALSA silent. */

}

#endif

static int open_alsa(out123_handle *ao)

{

const char *pcm_name;

snd_pcm_t *pcm=NULL;

debug1("open_alsa with %p", ao->userptr);

#ifndef DEBUG

if(AOQUIET) snd_lib_error_set_handler(error_ignorer);

#endif

pcm_name = ao->device ? ao->device : "default";

if (snd_pcm_open(&pcm, pcm_name, SND_PCM_STREAM_PLAYBACK, 0) < 0) {

if(!AOQUIET) error1("cannot open device %s", pcm_name);

return -1;

}

ao->userptr = pcm;

if (ao->format != -1) {

/* we're going to play: initalize sample format */

return initialize_device(ao);

} else {

/* query mode; sample format will be set for each query */

return 0;

}

}

static int get_formats_alsa(out123_handle *ao)

{

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

snd_pcm_hw_params_t *hw;

unsigned int rate;

int supported_formats, i;

snd_pcm_hw_params_alloca(&hw);

if (snd_pcm_hw_params_any(pcm, hw) < 0) {

if(!AOQUIET) error("get_formats_alsa(): no configuration available");

return -1;

}

if (snd_pcm_hw_params_set_access(pcm, hw, SND_PCM_ACCESS_RW_INTERLEAVED) < 0)

return -1;

if (snd_pcm_hw_params_set_channels(pcm, hw, ao->channels) < 0)

return 0;

rate = ao->rate;

if (snd_pcm_hw_params_set_rate_near(pcm, hw, &rate, NULL) < 0)

return -1;

if (!rates_match(ao->rate, rate))

return 0;

supported_formats = 0;

for (i = 0; i < NUM_FORMATS; ++i) {

if (snd_pcm_hw_params_test_format(pcm, hw, format_map[i].alsa) == 0)

supported_formats |= format_map[i].mpg123;

}

return supported_formats;

}

static int write_alsa(out123_handle *ao, unsigned char *buf, int bytes)

{

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

snd_pcm_uframes_t frames;

snd_pcm_sframes_t written;

frames = snd_pcm_bytes_to_frames(pcm, bytes);

while

( /* Try to write, recover if error, try again if recovery successful. */

(written = snd_pcm_writei(pcm, buf, frames)) < 0

&& snd_pcm_recover(pcm, (int)written, 0) == 0

)

{

debug2("recovered from alsa issue %i while trying to write %lu frames", (int)written, (unsigned long)frames);

}

if(written < 0)

{

error1("Fatal problem with alsa output, error %i.", (int)written);

return -1;

}

else return snd_pcm_frames_to_bytes(pcm, written);

}

static void flush_alsa(out123_handle *ao)

{

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

/* is this the optimal solution? - we should figure out what we really whant from this function */

debug("alsa drop");

snd_pcm_drop(pcm);

debug("alsa prepare");

snd_pcm_prepare(pcm);

debug("alsa flush done");

}

static void drain_alsa(out123_handle *ao)

{

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

debug1("drain_alsa with %p", ao->userptr);

snd_pcm_drain(pcm);

}

static int close_alsa(out123_handle *ao)

{

snd_pcm_t *pcm=(snd_pcm_t*)ao->userptr;

debug1("close_alsa with %p", ao->userptr);

if(pcm != NULL) /* be really generous for being called without any device opening */

{

ao->userptr = NULL; /* Should alsa do this or the module wrapper? */

return snd_pcm_close(pcm);

}

else return 0;

}

static int init_alsa(out123_handle* ao)

{

if (ao==NULL) return -1;

/* Set callbacks */

ao->open = open_alsa;

ao->flush = flush_alsa;

ao->drain = drain_alsa;

ao->write = write_alsa;

ao->get_formats = get_formats_alsa;

ao->close = close_alsa;

/* Success */

return 0;

}

/*

Module information data structure

*/

mpg123_module_t mpg123_output_module_info = {

/* api_version */ MPG123_MODULE_API_VERSION,

/* name */ "alsa",

/* description */ "Output audio using Advanced Linux Sound Architecture (ALSA).",

/* revision */ "$Rev:$",

/* handle */ NULL,

/* init_output */ init_alsa,

};