ref: a30de9ea3744f99cbc73148ea98dbcd4f048ff6f
dir: /src/alsa.c/
/* libSoX device driver: ALSA (c) 2006-9 SoX contributors
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "sox_i.h"
#include <alsa/asoundlib.h>
typedef struct {
snd_pcm_uframes_t buf_len, period;
snd_pcm_t * pcm;
char * buf;
int format;
} priv_t;
static const int bytes_size[] = {1, 2, 4}, encs[][3] = {
{SND_PCM_FORMAT_S8, SND_PCM_FORMAT_S16, SND_PCM_FORMAT_S24},
{SND_PCM_FORMAT_U8, SND_PCM_FORMAT_U16, SND_PCM_FORMAT_U24}};
#define NBYTES bytes_size[(ft->encoding.bits_per_sample >> 3) - 1]
static int select_format(sox_encoding_t * e, unsigned * bits, snd_pcm_format_mask_t const * mask, int * format)
{
unsigned does[3], i, j, k = (*bits >> 3) - 1;
if (k > 2 || (*e != SOX_ENCODING_SIGN2 && *e != SOX_ENCODING_UNSIGNED))
return -1;
for (i = 0; i < 3; ++i) for (does[i] = 0, j = 0; j < 2; ++j)
does[i] |= snd_pcm_format_mask_test(mask, encs[j][i]);
if (!does[k])
k = 1;
while (!does[k]) if ((k = (k + 1 ) % 3) == 1)
return -1;
*bits = (k + 1) << 3;
if (*e == SOX_ENCODING_SIGN2 && !snd_pcm_format_mask_test(mask, encs[0][k]))
*e = SOX_ENCODING_UNSIGNED;
*format = encs[*e == SOX_ENCODING_UNSIGNED][k];
return 0;
}
#define _(x,y) do {if ((err = x y) < 0) {lsx_fail_errno(ft, SOX_EPERM, #x " error: %s", snd_strerror(err)); goto error;} } while (0)
static int setup(sox_format_t * ft)
{
priv_t * p = (priv_t *)ft->priv;
snd_pcm_hw_params_t * params = NULL;
snd_pcm_format_mask_t * mask = NULL;
snd_pcm_uframes_t min, max;
unsigned n;
int err;
_(snd_pcm_open, (&p->pcm, ft->filename, ft->mode == 'r'? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK, 0));
_(snd_pcm_hw_params_malloc, (¶ms));
_(snd_pcm_hw_params_any, (p->pcm, params));
#if SND_LIB_VERSION >= 0x010009 /* Disable alsa-lib resampling: */
_(snd_pcm_hw_params_set_rate_resample, (p->pcm, params, 0));
#endif
_(snd_pcm_hw_params_set_access, (p->pcm, params, SND_PCM_ACCESS_RW_INTERLEAVED));
_(snd_pcm_format_mask_malloc, (&mask)); /* Set format: */
snd_pcm_hw_params_get_format_mask(params, mask);
_(select_format, (&ft->encoding.encoding, &ft->encoding.bits_per_sample, mask, &p->format));
_(snd_pcm_hw_params_set_format, (p->pcm, params, p->format));
snd_pcm_format_mask_free(mask), mask = NULL;
n = ft->signal.rate; /* Set rate: */
_(snd_pcm_hw_params_set_rate_near, (p->pcm, params, &n, 0));
ft->signal.rate = n;
n = ft->signal.channels; /* Set channels: */
_(snd_pcm_hw_params_set_channels_near, (p->pcm, params, &n));
ft->signal.channels = n;
/* Set buf_len > > sox_globals.bufsiz for no underrun: */
p->buf_len = sox_globals.bufsiz * 8 / NBYTES / ft->signal.channels;
_(snd_pcm_hw_params_get_buffer_size_min, (params, &min));
_(snd_pcm_hw_params_get_buffer_size_max, (params, &max));
p->period = range_limit(p->buf_len, min, max) / 8;
p->buf_len = p->period * 8;
_(snd_pcm_hw_params_set_period_size_near, (p->pcm, params, &p->period, 0));
_(snd_pcm_hw_params_set_buffer_size_near, (p->pcm, params, &p->buf_len));
if (p->period * 2 > p->buf_len) {
lsx_fail_errno(ft, SOX_EPERM, "buffer too small");
goto error;
}
_(snd_pcm_hw_params, (p->pcm, params)); /* Configure ALSA */
snd_pcm_hw_params_free(params), params = NULL;
_(snd_pcm_prepare, (p->pcm));
p->buf_len *= ft->signal.channels; /* No longer in `frames' */
p->buf = lsx_malloc(p->buf_len * NBYTES);
return SOX_SUCCESS;
error:
if (mask) snd_pcm_format_mask_free(mask);
if (params) snd_pcm_hw_params_free(params);
return SOX_EOF;
}
static int recover(sox_format_t * ft, snd_pcm_t * pcm, int err)
{
if (err == -EPIPE)
lsx_warn("%s-run", ft->mode == 'r'? "over" : "under");
else if (err != -ESTRPIPE)
lsx_warn("%s", snd_strerror(err));
else while ((err = snd_pcm_resume(pcm)) == -EAGAIN) {
lsx_report("suspended");
sleep(1); /* Wait until the suspend flag is released */
}
if (err < 0 && (err = snd_pcm_prepare(pcm)) < 0)
lsx_fail_errno(ft, SOX_EPERM, "%s", snd_strerror(err));
return err;
}
static size_t read_(sox_format_t * ft, sox_sample_t * buf, size_t len)
{
priv_t * p = (priv_t *)ft->priv;
snd_pcm_sframes_t i, n;
size_t done;
len = min(len, p->buf_len);
for (done = 0; done < len; done += n) {
do {
n = snd_pcm_readi(p->pcm, p->buf, (len - done) / ft->signal.channels);
if (n < 0 && recover(ft, p->pcm, (int)n) < 0)
return 0;
} while (n <= 0);
i = n *= ft->signal.channels;
switch (p->format) {
case SND_PCM_FORMAT_S8: {
int8_t * buf1 = (int8_t *)p->buf;
while (i--) *buf++ = SOX_SIGNED_8BIT_TO_SAMPLE(*buf1++,);
break;
}
case SND_PCM_FORMAT_U8: {
uint8_t * buf1 = (uint8_t *)p->buf;
while (i--) *buf++ = SOX_UNSIGNED_8BIT_TO_SAMPLE(*buf1++,);
break;
}
case SND_PCM_FORMAT_S16: {
int16_t * buf1 = (int16_t *)p->buf;
if (ft->encoding.reverse_bytes) while (i--)
*buf++ = SOX_SIGNED_16BIT_TO_SAMPLE(lsx_swapw(*buf1++),);
else
while (i--) *buf++ = SOX_SIGNED_16BIT_TO_SAMPLE(*buf1++,);
break;
}
case SND_PCM_FORMAT_U16: {
uint16_t * buf1 = (uint16_t *)p->buf;
if (ft->encoding.reverse_bytes) while (i--)
*buf++ = SOX_UNSIGNED_16BIT_TO_SAMPLE(lsx_swapw(*buf1++),);
else
while (i--) *buf++ = SOX_UNSIGNED_16BIT_TO_SAMPLE(*buf1++,);
break;
}
case SND_PCM_FORMAT_S24: {
int24_t * buf1 = (int24_t *)p->buf;
while (i--) *buf++ = SOX_SIGNED_24BIT_TO_SAMPLE(*buf1++,);
break;
}
case SND_PCM_FORMAT_U24: {
uint24_t * buf1 = (uint24_t *)p->buf;
while (i--) *buf++ = SOX_UNSIGNED_24BIT_TO_SAMPLE(*buf1++,);
break;
}
default: lsx_fail_errno(ft, SOX_EFMT, "invalid format");
return 0;
}
}
return len;
}
static size_t write_(sox_format_t * ft, sox_sample_t const * buf, size_t len)
{
priv_t * p = (priv_t *)ft->priv;
size_t done, i, n;
snd_pcm_sframes_t actual;
SOX_SAMPLE_LOCALS;
for (done = 0; done < len; done += n) {
i = n = min(len - done, p->buf_len);
switch (p->format) {
case SND_PCM_FORMAT_S8: {
int8_t * buf1 = (int8_t *)p->buf;
while (i--) *buf1++ = SOX_SAMPLE_TO_SIGNED_8BIT(*buf++, ft->clips);
break;
}
case SND_PCM_FORMAT_U8: {
uint8_t * buf1 = (uint8_t *)p->buf;
while (i--) *buf1++ = SOX_SAMPLE_TO_UNSIGNED_8BIT(*buf++, ft->clips);
break;
}
case SND_PCM_FORMAT_S16: {
int16_t * buf1 = (int16_t *)p->buf;
if (ft->encoding.reverse_bytes) while (i--)
*buf1++ = lsx_swapw(SOX_SAMPLE_TO_SIGNED_16BIT(*buf++, ft->clips));
else
while (i--) *buf1++ = SOX_SAMPLE_TO_SIGNED_16BIT(*buf++, ft->clips);
break;
}
case SND_PCM_FORMAT_U16: {
uint16_t * buf1 = (uint16_t *)p->buf;
if (ft->encoding.reverse_bytes) while (i--)
*buf1++ = lsx_swapw(SOX_SAMPLE_TO_UNSIGNED_16BIT(*buf++, ft->clips));
else
while (i--) *buf1++ = SOX_SAMPLE_TO_UNSIGNED_16BIT(*buf++, ft->clips);
break;
}
case SND_PCM_FORMAT_S24: {
int24_t * buf1 = (int24_t *)p->buf;
while (i--) *buf1++ = SOX_SAMPLE_TO_SIGNED_24BIT(*buf++, ft->clips);
break;
}
case SND_PCM_FORMAT_U24: {
uint24_t * buf1 = (uint24_t *)p->buf;
while (i--) *buf1++ = SOX_SAMPLE_TO_UNSIGNED_24BIT(*buf++, ft->clips);
break;
}
}
for (i = 0; i < n; i += actual * ft->signal.channels) do {
actual = snd_pcm_writei(
p->pcm, p->buf + i * NBYTES, (n - i) / ft->signal.channels);
if (errno == EAGAIN) /* Happens naturally; don't report it: */
errno = 0;
if (actual < 0 && recover(ft, p->pcm, (int)actual) < 0)
return 0;
} while (actual < 0);
}
return len;
}
static int stop(sox_format_t * ft)
{
priv_t * p = (priv_t *)ft->priv;
snd_pcm_close(p->pcm);
free(p->buf);
return SOX_SUCCESS;
}
static int stop_write(sox_format_t * ft)
{
priv_t * p = (priv_t *)ft->priv;
size_t n = ft->signal.channels * p->period, npad = n - (ft->olength % n);
sox_sample_t * buf = lsx_calloc(npad, sizeof(*buf)); /* silent samples */
if (npad != n) /* pad to hardware period: */
write_(ft, buf, npad);
free(buf);
snd_pcm_drain(p->pcm);
return stop(ft);
}
LSX_FORMAT_HANDLER(alsa)
{
static char const * const names[] = {"alsa", NULL};
static unsigned const write_encodings[] = {
SOX_ENCODING_SIGN2, 24, 16, 8, 0, SOX_ENCODING_UNSIGNED, 24, 16, 8, 0, 0};
static sox_format_handler_t const handler = {SOX_LIB_VERSION_CODE,
"Advanced Linux Sound Architecture device driver",
names, SOX_FILE_DEVICE | SOX_FILE_NOSTDIO,
setup, read_, stop, setup, write_, stop_write,
NULL, write_encodings, NULL, sizeof(priv_t)
};
return &handler;
}