ref: fffe16e7e5f232fbcee82380dd2f85a1bd9a1be8
dir: /src/alsa.c/
/* ALSA sound driver
*
* converted to alsalib cbagwell 20050914
* added by Jimen Ching (jching@flex.com) 19990207
* based on info grabed from aplay.c in alsa-utils package.
* Updated for ALSA 0.9.X API 20020824.
*
* Copyright 1997-2005 Jimen Ching And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Jimen Ching And Sundry Contributors are not
* responsible for the consequences of using this software.
*/
#include "st_i.h"
#ifdef HAVE_ALSA
#include <alsa/asoundlib.h>
typedef struct alsa_priv
{
snd_pcm_t *pcm_handle;
char *buf;
st_size_t buf_size;
} *alsa_priv_t;
static int get_format(ft_t ft, snd_pcm_format_mask_t *fmask, int *fmt);
static int st_alsasetup(ft_t ft, snd_pcm_stream_t mode)
{
int fmt = SND_PCM_FORMAT_S16;
int err;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_hw_params_t *hw_params = NULL;
unsigned int min_rate, max_rate;
unsigned int min_chan, max_chan;
unsigned int rate;
snd_pcm_uframes_t buffer_size, buffer_size_min, buffer_size_max;
snd_pcm_uframes_t period_size, period_size_min, period_size_max;
int dir;
snd_pcm_format_mask_t *fmask = NULL;
if ((err = snd_pcm_open(&(alsa->pcm_handle), ft->filename,
mode, 0)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot open audio device");
goto open_error;
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0)
{
st_fail_errno(ft, ST_ENOMEM,
"cannot allocate hardware parameter structure");
goto open_error;
}
if ((err = snd_pcm_hw_params_any(alsa->pcm_handle, hw_params)) < 0)
{
st_fail_errno(ft, ST_EPERM,
"cannot initialize hardware parameter structure");
goto open_error;
}
#if SND_LIB_VERSION >= 0x010009
/* Turn off software resampling */
rate = 0;
err = snd_pcm_hw_params_set_rate_resample(alsa->pcm_handle, hw_params,
rate);
if (err < 0) {
st_fail_errno(ft, ST_EPERM, "Resampling setup failed for playback");
goto open_error;
}
#endif
if ((err = snd_pcm_hw_params_set_access(alsa->pcm_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
{
st_fail_errno(ft, ST_EPERM,
"cannot set access type");
goto open_error;
}
snd_pcm_hw_params_get_channels_min(hw_params, &min_chan);
snd_pcm_hw_params_get_channels_max(hw_params, &max_chan);
if (ft->signal.channels == 0)
ft->signal.channels = min_chan;
else
if (ft->signal.channels > max_chan)
ft->signal.channels = max_chan;
else if (ft->signal.channels < min_chan)
ft->signal.channels = min_chan;
if (snd_pcm_format_mask_malloc(&fmask) < 0)
goto open_error;
snd_pcm_hw_params_get_format_mask(hw_params, fmask);
if (get_format(ft, fmask, &fmt) < 0)
goto open_error;
snd_pcm_format_mask_free(fmask);
fmask = NULL;
if ((err = snd_pcm_hw_params_set_format(alsa->pcm_handle,
hw_params, fmt)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set sample format");
goto open_error;
}
rate = ft->signal.rate;
snd_pcm_hw_params_get_rate_min(hw_params, &min_rate, &dir);
snd_pcm_hw_params_get_rate_max(hw_params, &max_rate, &dir);
rate = max(rate, min_rate);
rate = min(rate, max_rate);
if (rate != ft->signal.rate)
{
st_report("hardware does not support sample-rate %i; changing to %i.", ft->signal.rate, rate);
ft->signal.rate = rate;
}
dir = 0;
if ((err = snd_pcm_hw_params_set_rate_near(alsa->pcm_handle,
hw_params,
&rate,
&dir)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set sample rate");
goto open_error;
}
snd_pcm_hw_params_get_rate(hw_params,
&rate,
&dir);
if (rate != ft->signal.rate)
{
st_report("Could not set exact rate of %d. Approximating with %d",
ft->signal.rate, rate);
}
snd_pcm_hw_params_get_rate(hw_params, &rate, &dir);
if ((err = snd_pcm_hw_params_set_channels(alsa->pcm_handle,
hw_params,
ft->signal.channels)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set channel count");
goto open_error;
}
buffer_size = (ST_BUFSIZ / sizeof(st_sample_t) / ft->signal.channels);
if (snd_pcm_hw_params_get_buffer_size_min(hw_params, &buffer_size_min) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error getting min buffer size.");
goto open_error;
}
if (snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size_max) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error getting max buffer size.");
goto open_error;
}
dir = 0;
if (snd_pcm_hw_params_get_period_size_min(hw_params,
&period_size_min, &dir) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error getting min period size.");
goto open_error;
}
dir = 0;
if (snd_pcm_hw_params_get_period_size_max(hw_params,
&period_size_max, &dir) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error getting max buffer size.");
goto open_error;
}
if (buffer_size_max < buffer_size)
buffer_size = buffer_size_max;
else if (buffer_size_min > buffer_size)
buffer_size = buffer_size_min;
period_size = buffer_size / 8;
buffer_size = period_size * 8;
dir = 0;
if (snd_pcm_hw_params_set_period_size_near(alsa->pcm_handle, hw_params,
&period_size, &dir) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error setting periods.");
goto open_error;
}
snd_pcm_hw_params_get_period_size(hw_params, &period_size, &dir);
dir = 0;
if (snd_pcm_hw_params_set_buffer_size_near(alsa->pcm_handle, hw_params,
&buffer_size) < 0) {
st_fail_errno(ft, ST_EPERM, "Error setting buffer size.");
goto open_error;
}
snd_pcm_hw_params_get_buffer_size(hw_params, &buffer_size);
if (period_size*2 > buffer_size)
{
st_fail_errno(ft, ST_EPERM, "Buffer too small. Could not use.");
goto open_error;
}
if ((err = snd_pcm_hw_params(alsa->pcm_handle, hw_params)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set parameters");
goto open_error;
}
snd_pcm_hw_params_free(hw_params);
hw_params = NULL;
if ((err = snd_pcm_prepare(alsa->pcm_handle)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot prepare audio interface for use");
goto open_error;
}
alsa->buf_size = buffer_size * ft->signal.size * ft->signal.channels;
alsa->buf = xmalloc(alsa->buf_size);
return (ST_SUCCESS);
open_error:
if (fmask)
snd_pcm_format_mask_free(fmask);
if (hw_params)
snd_pcm_hw_params_free(hw_params);
return ST_EOF;
}
/*
* Underrun and suspend recovery
*/
static int xrun_recovery(snd_pcm_t *handle, int err)
{
if (err == -EPIPE)
{ /* under-run */
err = snd_pcm_prepare(handle);
if (err < 0)
st_warn("Can't recovery from overrun, prepare failed: %s", snd_strerror(err));
return 0;
}
else
{
if (err == -ESTRPIPE)
{
/* wait until the suspend flag is released */
while ((err = snd_pcm_resume(handle)) == -EAGAIN)
sleep(1);
if (err < 0)
{
err = snd_pcm_prepare(handle);
if (err < 0)
st_warn("Can't recovery from suspend, prepare failed: %s", snd_strerror(err));
}
}
return 0;
}
return err;
}
/*
* Do anything required before you start reading samples.
* Read file header.
* Find out sampling rate,
* size and encoding of samples,
* mono/stereo/quad.
*/
static int st_alsastartread(ft_t ft)
{
return st_alsasetup(ft, SND_PCM_STREAM_CAPTURE);
}
static void st_ub_read_buf(st_sample_t *buf1, char const * buf2, st_size_t len, char swap UNUSED, st_size_t * clips UNUSED)
{
while (len--)
*buf1++ = ST_UNSIGNED_BYTE_TO_SAMPLE(*((unsigned char *)buf2++),);
}
static void st_sb_read_buf(st_sample_t *buf1, char const * buf2, st_size_t len, char swap UNUSED, st_size_t * clips UNUSED)
{
while (len--)
*buf1++ = ST_SIGNED_BYTE_TO_SAMPLE(*((int8_t *)buf2++),);
}
static void st_uw_read_buf(st_sample_t *buf1, char const * buf2, st_size_t len, char swap, st_size_t * clips UNUSED)
{
while (len--)
{
uint16_t datum = *((uint16_t *)buf2);
buf2++; buf2++;
if (swap)
datum = st_swapw(datum);
*buf1++ = ST_UNSIGNED_WORD_TO_SAMPLE(datum,);
}
}
static void st_sw_read_buf(st_sample_t *buf1, char const * buf2, st_size_t len, char swap, st_size_t * clips UNUSED)
{
while (len--)
{
int16_t datum = *((int16_t *)buf2);
buf2++; buf2++;
if (swap)
datum = st_swapw(datum);
*buf1++ = ST_SIGNED_WORD_TO_SAMPLE(datum,);
}
}
static st_size_t st_alsaread(ft_t ft, st_sample_t *buf, st_size_t nsamp)
{
st_size_t len;
int err;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*read_buf)(st_sample_t *, char const *, st_size_t, char, st_size_t *) = 0;
switch(ft->signal.size) {
case ST_SIZE_BYTE:
switch(ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
read_buf = st_sb_read_buf;
break;
case ST_ENCODING_UNSIGNED:
read_buf = st_ub_read_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
case ST_SIZE_WORD:
switch(ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
read_buf = st_sw_read_buf;
break;
case ST_ENCODING_UNSIGNED:
read_buf = st_uw_read_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this data size for this handler");
return ST_EOF;
}
/* Prevent overflow */
if (nsamp > alsa->buf_size/ft->signal.size)
nsamp = (alsa->buf_size/ft->signal.size);
len = 0;
while (len < nsamp)
{
/* ALSA library takes "frame" counts. */
err = snd_pcm_readi(alsa->pcm_handle, alsa->buf,
(nsamp-len)/ft->signal.channels);
if (err < 0)
{
if (xrun_recovery(alsa->pcm_handle, err) < 0)
{
st_fail_errno(ft, ST_EPERM, "ALSA write error");
return ST_EOF;
}
}
else
{
read_buf(buf+(len*sizeof(st_sample_t)), alsa->buf, err, ft->signal.reverse_bytes, &ft->clips);
len += err * ft->signal.channels;
}
}
return len;
}
static int st_alsastopread(ft_t ft)
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return ST_SUCCESS;
}
static int st_alsastartwrite(ft_t ft)
{
return st_alsasetup(ft, SND_PCM_STREAM_PLAYBACK);
}
static void st_ub_write_buf(char* buf1, st_sample_t const * buf2, st_size_t len, char swap UNUSED, st_size_t * clips)
{
while (len--)
*(uint8_t *)buf1++ = ST_SAMPLE_TO_UNSIGNED_BYTE(*buf2++, *clips);
}
static void st_sb_write_buf(char *buf1, st_sample_t const * buf2, st_size_t len, char swap UNUSED, st_size_t * clips)
{
while (len--)
*(int8_t *)buf1++ = ST_SAMPLE_TO_SIGNED_BYTE(*buf2++, *clips);
}
static void st_uw_write_buf(char *buf1, st_sample_t const * buf2, st_size_t len, char swap, st_size_t * clips)
{
while (len--)
{
uint16_t datum = ST_SAMPLE_TO_UNSIGNED_WORD(*buf2++, *clips);
if (swap)
datum = st_swapw(datum);
*(uint16_t *)buf1 = datum;
buf1++; buf1++;
}
}
static void st_sw_write_buf(char *buf1, st_sample_t const * buf2, st_size_t len, char swap, st_size_t * clips)
{
while (len--)
{
int16_t datum = ST_SAMPLE_TO_SIGNED_WORD(*buf2++, *clips);
if (swap)
datum = st_swapw(datum);
*(int16_t *)buf1 = datum;
buf1++; buf1++;
}
}
static st_size_t st_alsawrite(ft_t ft, const st_sample_t *buf, st_size_t nsamp)
{
st_size_t osamp, done;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*write_buf)(char *, const st_sample_t *, st_size_t, char, st_size_t *) = 0;
switch(ft->signal.size) {
case ST_SIZE_BYTE:
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
write_buf = st_sb_write_buf;
break;
case ST_ENCODING_UNSIGNED:
write_buf = st_ub_write_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"this encoding is not supported for this data size");
return 0;
}
break;
case ST_SIZE_WORD:
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
write_buf = st_sw_write_buf;
break;
case ST_ENCODING_UNSIGNED:
write_buf = st_uw_write_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"this encoding is not supported for this data size");
return 0;
}
break;
default:
st_fail_errno(ft,ST_EFMT,"this data size is not supported by this handler");
return 0;
}
for (done = 0; done < nsamp; done += osamp) {
int err;
st_size_t len;
osamp = min(nsamp - done, alsa->buf_size / ft->signal.size);
write_buf(alsa->buf, buf, osamp, ft->signal.reverse_bytes, &ft->clips);
buf += osamp;
for (len = 0; len < osamp;) {
err = snd_pcm_writei(alsa->pcm_handle,
alsa->buf + (len * ft->signal.size),
(osamp - len) / ft->signal.channels);
if (err < 0 && xrun_recovery(alsa->pcm_handle, err) < 0) {
st_fail_errno(ft, ST_EPERM, "ALSA write error");
return 0;
} else
len += err * ft->signal.channels;
}
}
return nsamp;
}
static int st_alsastopwrite(ft_t ft)
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_drain(alsa->pcm_handle);
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return ST_SUCCESS;
}
#define EMSGFMT "ALSA driver does not support %s %s output"
static int get_format(ft_t ft, snd_pcm_format_mask_t *fmask, int *fmt)
{
if (ft->signal.size == -1)
ft->signal.size = ST_SIZE_WORD;
if (ft->signal.encoding == ST_ENCODING_UNKNOWN)
{
if (ft->signal.size == ST_SIZE_WORD)
ft->signal.encoding = ST_ENCODING_SIGN2;
else
ft->signal.encoding = ST_ENCODING_UNSIGNED;
}
if (ft->signal.size != ST_SIZE_WORD &&
ft->signal.size != ST_SIZE_BYTE)
{
st_report("driver only supports byte and word samples. Changing to word.");
ft->signal.size = ST_SIZE_WORD;
}
if (ft->signal.encoding != ST_ENCODING_SIGN2 &&
ft->signal.encoding != ST_ENCODING_UNSIGNED)
{
if (ft->signal.size == ST_SIZE_WORD)
{
st_report("driver only supports signed and unsigned samples. Changing to signed.");
ft->signal.encoding = ST_ENCODING_SIGN2;
}
else
{
st_report("driver only supports signed and unsigned samples. Changing to unsigned.");
ft->signal.encoding = ST_ENCODING_UNSIGNED;
}
}
/* Some hardware only wants to work with 8-bit or 16-bit data */
if (ft->signal.size == ST_SIZE_BYTE)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_report("driver doesn't supported byte samples. Changing to words.");
ft->signal.size = ST_SIZE_WORD;
}
}
else if (ft->signal.size == ST_SIZE_WORD)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("driver doesn't supported word samples. Changing to bytes.");
ft->signal.size = ST_SIZE_BYTE;
}
}
else
{
if ((snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) ||
(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("driver doesn't supported %s samples. Changing to words.", st_sizes_str[(unsigned char)ft->signal.size]);
ft->signal.size = ST_SIZE_WORD;
}
else
{
st_report("driver doesn't supported %s samples. Changing to bytes.", st_sizes_str[(unsigned char)ft->signal.size]);
ft->signal.size = ST_SIZE_BYTE;
}
}
if (ft->signal.size == ST_SIZE_BYTE) {
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_report("driver doesn't supported signed byte samples. Changing to unsigned bytes.");
ft->signal.encoding = ST_ENCODING_UNSIGNED;
}
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
st_report("driver doesn't supported unsigned byte samples. Changing to signed bytes.");
ft->signal.encoding = ST_ENCODING_SIGN2;
}
break;
default:
break;
}
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed byte samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_S8;
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned byte samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_U8;
break;
default:
break;
}
}
else if (ft->signal.size == ST_SIZE_WORD) {
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("driver does not support signed word samples. Changing to unsigned words.");
ft->signal.encoding = ST_ENCODING_UNSIGNED;
}
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
st_report("driver does not support unsigned word samples. Changing to signed words.");
ft->signal.encoding = ST_ENCODING_SIGN2;
}
break;
default:
break;
}
switch (ft->signal.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed word samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_S16_LE;
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned word samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_U16_LE;
break;
default:
break;
}
}
else {
st_fail_errno(ft,ST_EFMT,EMSGFMT,st_encodings_str[(unsigned char)ft->signal.encoding], st_sizes_str[(unsigned char)ft->signal.size]);
return ST_EOF;
}
return 0;
}
/* /dev/snd/pcmXX */
static const char *alsanames[] = {
"alsa",
NULL
};
static st_format_t st_alsa_format = {
alsanames,
NULL,
ST_FILE_DEVICE | ST_FILE_NOSTDIO,
st_alsastartread,
st_alsaread,
st_alsastopread,
st_alsastartwrite,
st_alsawrite,
st_alsastopwrite,
st_format_nothing_seek
};
const st_format_t *st_alsa_format_fn(void)
{
return &st_alsa_format;
}
#endif /* HAVE_ALSA */