ref: 4b2ef597e4d4f5e7f05045e55db76dd4fabbe7f5
dir: /src/alsa.c/
/*
* Copyright 1997 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.
*/
/* Direct to ALSA sound driver
*
* 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.
*/
#include "st_i.h"
#if defined(HAVE_ALSA)
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
static int get_format(ft_t ft, int formats, int *fmt);
#if HAVE_ALSA9
#include <limits.h>
#include <sound/asound.h>
/* Backwards compatibility. */
#define SND_PCM_SFMT_S8 SNDRV_PCM_FORMAT_S8
#define SND_PCM_SFMT_U8 SNDRV_PCM_FORMAT_U8
#define SND_PCM_SFMT_S16_LE SNDRV_PCM_FORMAT_S16
#define SND_PCM_SFMT_U16_LE SNDRV_PCM_FORMAT_U16
#define SND_PCM_FMT_S8 (1 << SNDRV_PCM_FORMAT_S8)
#define SND_PCM_FMT_U8 (1 << SNDRV_PCM_FORMAT_U8)
#define SND_PCM_FMT_S16 (1 << SNDRV_PCM_FORMAT_S16)
#define SND_PCM_FMT_U16 (1 << SNDRV_PCM_FORMAT_U16)
#define alsa_params_masks(p, i) \
(&((p)->masks[(i)-SNDRV_PCM_HW_PARAM_FIRST_MASK]))
#define alsa_params_intervals(p, i) \
(&((p)->intervals[(i)-SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]))
struct alsa_info
{
unsigned int formats;
unsigned int min_buffer_size;
unsigned int max_buffer_size;
unsigned int min_channels;
unsigned int max_channels;
unsigned int min_rate;
unsigned int max_rate;
unsigned int min_periods;
unsigned int max_periods;
unsigned int min_period_size;
unsigned int max_period_size;
};
struct alsa_setup
{
int format;
char channels;
st_rate_t rate;
size_t buffer_size;
int periods;
size_t period_size;
};
int
alsa_hw_info_get(fd, a_info, params)
int fd;
struct alsa_info *a_info;
struct sndrv_pcm_hw_params *params;
{
unsigned int i;
struct sndrv_mask *msk;
struct sndrv_interval *intr;
memset(params, '\0', sizeof(struct sndrv_pcm_hw_params));
for (i = 0; i <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; ++i)
{
if (i >= SNDRV_PCM_HW_PARAM_FIRST_MASK &&
i <= SNDRV_PCM_HW_PARAM_LAST_MASK)
{
msk = alsa_params_masks(params, i);
memset(msk->bits, 0xff, sizeof(msk->bits));
}
else
{
intr = alsa_params_intervals(params, i);
intr->min = 0;
intr->openmin = 0;
intr->max = UINT_MAX;
intr->openmax = 0;
intr->integer = 0;
intr->empty = 0;
}
params->cmask |= 1 << i;
params->rmask |= 1 << i;
}
if (ioctl(fd, SNDRV_PCM_IOCTL_HW_REFINE, params) < 0) {
return -1;
}
msk = alsa_params_masks(params, SNDRV_PCM_HW_PARAM_FORMAT);
a_info->formats = msk->bits[0]; /* Only care about first 32 bits. */
a_info->min_buffer_size = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_BUFFER_BYTES)->min;
a_info->max_buffer_size = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_BUFFER_BYTES)->max;
a_info->min_channels = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_CHANNELS)->min;
a_info->max_channels = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_CHANNELS)->max;
a_info->min_rate = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_RATE)->min;
a_info->max_rate = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_RATE)->max;
a_info->min_periods = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_PERIODS)->min;
a_info->max_periods = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_PERIODS)->max;
a_info->min_period_size = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_PERIOD_BYTES)->min;
a_info->max_period_size = alsa_params_intervals(params, SNDRV_PCM_HW_PARAM_PERIOD_BYTES)->max;
return 0;
}
int
alsa_hw_info_set(fd, params, setup)
int fd;
struct sndrv_pcm_hw_params *params;
struct alsa_setup *setup;
{
int i;
struct sndrv_mask *msk;
struct sndrv_interval *intr;
i = SNDRV_PCM_HW_PARAM_ACCESS;
msk = alsa_params_masks(params, i);
msk->bits[0] &= 1 << SNDRV_PCM_ACCESS_RW_INTERLEAVED; /* Only care about first 32 bits. */
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_FORMAT;
msk = alsa_params_masks(params, i);
msk->bits[0] &= 1 << setup->format; /* Only care about first 32 bits. */
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_CHANNELS;
intr = alsa_params_intervals(params, i);
intr->empty = 0;
intr->min = intr->max = setup->channels;
intr->openmin = intr->openmax = 0;
intr->integer = 1;
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_RATE;
intr = alsa_params_intervals(params, i);
intr->empty = 0;
intr->min = intr->max = setup->rate;
intr->openmin = intr->openmax = 0;
intr->integer = 1;
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_BUFFER_BYTES;
intr = alsa_params_intervals(params, i);
intr->empty = 0;
intr->min = intr->max = setup->buffer_size;
intr->openmin = intr->openmax = 0;
intr->integer = 1;
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_PERIODS;
intr = alsa_params_intervals(params, i);
intr->empty = 0;
intr->min = intr->max = setup->periods;
intr->openmin = intr->openmax = 0;
intr->integer = 1;
params->cmask = 1 << i;
params->rmask = 1 << i;
i = SNDRV_PCM_HW_PARAM_PERIOD_BYTES;
intr = alsa_params_intervals(params, i);
intr->empty = 0;
intr->min = intr->max = setup->period_size;
intr->openmin = intr->openmax = 0;
intr->integer = 1;
params->cmask = 1 << i;
params->rmask = 1 << i;
if (ioctl(fd, SNDRV_PCM_IOCTL_HW_PARAMS, params) < 0) {
return -1;
}
if (ioctl(fd, SNDRV_PCM_IOCTL_PREPARE) < 0) {
return -1;
}
return 0;
}
/*
* Do anything required before you start reading samples.
* Read file header.
* Find out sampling rate,
* size and encoding of samples,
* mono/stereo/quad.
*/
int st_alsastartread(ft)
ft_t ft;
{
int fmt;
struct alsa_info a_info;
struct alsa_setup a_setup;
struct sndrv_pcm_hw_params params;
if (alsa_hw_info_get(fileno(ft->fp), &a_info, ¶ms) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.count = 0;
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = a_info.max_buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < a_info.min_rate) ft->info.rate = 2 * a_info.min_rate;
else if (ft->info.rate > a_info.max_rate) ft->info.rate = a_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = a_info.min_channels;
else if (ft->info.channels > a_info.max_channels) ft->info.channels = a_info.max_channels;
if (get_format(ft, a_info.formats, &fmt) < 0)
return (ST_EOF);
a_setup.format = fmt;
a_setup.channels = ft->info.channels;
a_setup.rate = ft->info.rate;
a_setup.buffer_size = ft->file.size;
a_setup.periods = 16;
if (a_setup.periods < a_info.min_periods) a_setup.periods = a_info.min_periods;
else if (a_setup.periods > a_info.max_periods) a_setup.periods = a_info.max_periods;
a_setup.period_size = a_setup.buffer_size / a_setup.periods;
if (a_setup.period_size < a_info.min_period_size) a_setup.period_size = a_info.min_period_size;
else if (a_setup.period_size > a_info.max_period_size) a_setup.period_size = a_info.max_period_size;
if (alsa_hw_info_set(fileno(ft->fp), ¶ms, &a_setup) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
sigintreg(ft); /* Prepare to catch SIGINT */
return (ST_SUCCESS);
}
int st_alsastartwrite(ft)
ft_t ft;
{
int fmt;
struct alsa_info a_info;
struct alsa_setup a_setup;
struct sndrv_pcm_hw_params params;
if (alsa_hw_info_get(fileno(ft->fp), &a_info, ¶ms) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = a_info.max_buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < a_info.min_rate) ft->info.rate = 2 * a_info.min_rate;
else if (ft->info.rate > a_info.max_rate) ft->info.rate = a_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = a_info.min_channels;
else if (ft->info.channels > a_info.max_channels) ft->info.channels = a_info.max_channels;
if (get_format(ft, a_info.formats, &fmt) < 0)
return (ST_EOF);
a_setup.format = fmt;
a_setup.channels = ft->info.channels;
a_setup.rate = ft->info.rate;
a_setup.buffer_size = ft->file.size;
a_setup.periods = 16;
if (a_setup.periods < a_info.min_periods) a_setup.periods = a_info.min_periods;
else if (a_setup.periods > a_info.max_periods) a_setup.periods = a_info.max_periods;
a_setup.period_size = a_setup.buffer_size / a_setup.periods;
if (a_setup.period_size < a_info.min_period_size) a_setup.period_size = a_info.min_period_size;
else if (a_setup.period_size > a_info.max_period_size) a_setup.period_size = a_info.max_period_size;
if (alsa_hw_info_set(fileno(ft->fp), ¶ms, &a_setup) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
return(ST_SUCCESS);
}
int st_alsastopwrite(ft)
ft_t ft;
{
ioctl(fileno(ft->fp), SNDRV_PCM_IOCTL_DRAIN);
return(st_rawstopwrite(ft));
}
#else /* ! HAVE_ALSA9 */
#include <linux/asound.h>
#if HAVE_ALSA4 /* Start 0.4.x API */
int st_alsastartread(ft)
ft_t ft;
{
int bps, fmt, size;
snd_pcm_capture_info_t c_info;
snd_pcm_format_t format;
snd_pcm_capture_params_t c_params;
memset(&c_info, 0, sizeof(c_info));
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CAPTURE_INFO, &c_info) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.count = 0;
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = c_info.buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < c_info.min_rate) ft->info.rate = 2 * c_info.min_rate;
else if (ft->info.rate > c_info.max_rate) ft->info.rate = c_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = c_info.min_channels;
else if (ft->info.channels > c_info.max_channels) ft->info.channels = c_info.max_channels;
if (get_format(ft, c_info.hw_formats, &fmt) < 0)
return(ST_EOF);
memset(&format, 0, sizeof(format));
format.format = fmt;
format.rate = ft->info.rate;
format.channels = ft->info.channels;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CAPTURE_FORMAT, &format) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
size = ft->file.size;
bps = format.rate * format.channels;
if (ft->info.size == ST_SIZE_WORD) bps <<= 1;
bps >>= 2;
while (size > bps) size >>= 1;
if (size < 16) size = 16;
memset(&c_params, 0, sizeof(c_params));
c_params.fragment_size = size;
c_params.fragments_min = 1;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CAPTURE_PARAMS, &c_params) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
sigintreg(ft); /* Prepare to catch SIGINT */
return (ST_SUCCESS);
}
int st_alsastartwrite(ft)
ft_t ft;
{
int bps, fmt, size;
snd_pcm_playback_info_t p_info;
snd_pcm_format_t format;
snd_pcm_playback_params_t p_params;
memset(&p_info, 0, sizeof(p_info));
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_PLAYBACK_INFO, &p_info) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = p_info.buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < p_info.min_rate) ft->info.rate = 2 * p_info.min_rate;
else if (ft->info.rate > p_info.max_rate) ft->info.rate = p_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = p_info.min_channels;
else if (ft->info.channels > p_info.max_channels) ft->info.channels = p_info.max_channels;
if (get_format(ft, p_info.hw_formats, &fmt) < 0)
return(ST_EOF);
memset(&format, 0, sizeof(format));
format.format = fmt;
format.rate = ft->info.rate;
format.channels = ft->info.channels;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_PLAYBACK_FORMAT, &format) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
size = ft->file.size;
bps = format.rate * format.channels;
if (ft->info.size == ST_SIZE_WORD) bps <<= 1;
bps >>= 2;
while (size > bps) size >>= 1;
if (size < 16) size = 16;
memset(&p_params, 0, sizeof(p_params));
p_params.fragment_size = size;
p_params.fragments_max = -1;
p_params.fragments_room = 1;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_PLAYBACK_PARAMS, &p_params) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
return(ST_SUCCESS);
}
int st_alsastopwrite(ft)
ft_t ft;
{
/* Is there a drain operation for ALSA 0.4.X? */
return(st_rawstopwrite(ft));
}
#elif HAVE_ALSA5 /* Start 0.5.x API */
int st_alsastartread(ft)
ft_t ft;
{
int bps, fmt, size;
snd_pcm_channel_info_t c_info;
snd_pcm_channel_params_t c_params;
memset(&c_info, 0, sizeof(c_info));
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_INFO, &c_info) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.count = 0;
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = c_info.buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < c_info.min_rate) ft->info.rate = 2 * c_info.min_rate;
else if (ft->info.rate > c_info.max_rate) ft->info.rate = c_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = c_info.min_voices;
else if (ft->info.channels > c_info.max_voices) ft->info.channels = c_info.max_voices;
if (get_format(ft, c_info.formats, &fmt) < 0)
return (ST_EOF);
memset(&c_params, 0, sizeof(c_params));
c_params.format.format = fmt;
c_params.format.rate = ft->info.rate;
c_params.format.voices = ft->info.channels;
c_params.format.interleave = 1;
c_params.channel = SND_PCM_CHANNEL_CAPTURE;
c_params.mode = SND_PCM_MODE_BLOCK;
c_params.start_mode = SND_PCM_START_DATA;
c_params.stop_mode = SND_PCM_STOP_STOP;
bps = c_params.format.rate * c_params.format.voices;
if (ft->info.size == ST_SIZE_WORD) bps <<= 1;
bps >>= 2;
size = 1;
while ((size << 1) < bps) size <<= 1;
if (size > ft->file.size) size = ft->file.size;
if (size < c_info.min_fragment_size) size = c_info.min_fragment_size;
else if (size > c_info.max_fragment_size) size = c_info.max_fragment_size;
c_params.buf.block.frag_size = size;
c_params.buf.block.frags_max = 32;
c_params.buf.block.frags_min = 1;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_PARAMS, &c_params) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_PREPARE) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
sigintreg(ft); /* Prepare to catch SIGINT */
return (ST_SUCCESS);
}
int st_alsastartwrite(ft)
ft_t ft;
{
int bps, fmt, size;
snd_pcm_channel_info_t p_info;
snd_pcm_channel_params_t p_params;
memset(&p_info, 0, sizeof(p_info));
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_INFO, &p_info) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
ft->file.pos = 0;
ft->file.eof = 0;
ft->file.size = p_info.buffer_size;
if ((ft->file.buf = malloc (ft->file.size)) == NULL) {
st_fail_errno(ft,ST_ENOMEM,"unable to allocate output buffer of size %d", ft->file.size);
return(ST_EOF);
}
if (ft->info.rate < p_info.min_rate) ft->info.rate = 2 * p_info.min_rate;
else if (ft->info.rate > p_info.max_rate) ft->info.rate = p_info.max_rate;
if (ft->info.channels == -1) ft->info.channels = p_info.min_voices;
else if (ft->info.channels > p_info.max_voices) ft->info.channels = p_info.max_voices;
if (get_format(ft, p_info.formats, &fmt) < 0)
return(ST_EOF);
memset(&p_params, 0, sizeof(p_params));
p_params.format.format = fmt;
p_params.format.rate = ft->info.rate;
p_params.format.voices = ft->info.channels;
p_params.format.interleave = 1;
p_params.channel = SND_PCM_CHANNEL_PLAYBACK;
p_params.mode = SND_PCM_MODE_BLOCK;
p_params.start_mode = SND_PCM_START_DATA;
p_params.stop_mode = SND_PCM_STOP_STOP;
bps = p_params.format.rate * p_params.format.voices;
if (ft->info.size == ST_SIZE_WORD) bps <<= 1;
bps >>= 2;
size = 1;
while ((size << 1) < bps) size <<= 1;
if (size > ft->file.size) size = ft->file.size;
if (size < p_info.min_fragment_size) size = p_info.min_fragment_size;
else if (size > p_info.max_fragment_size) size = p_info.max_fragment_size;
p_params.buf.block.frag_size = size;
p_params.buf.block.frags_max = -1; /* Little trick (playback only) */
p_params.buf.block.frags_min = 1;
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_PARAMS, &p_params) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
if (ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_PREPARE) < 0) {
st_fail_errno(ft,ST_EPERM,"ioctl operation failed %d",errno);
return(ST_EOF);
}
/* Change to non-buffered I/O */
setvbuf(ft->fp, NULL, _IONBF, sizeof(char) * ft->file.size);
return(ST_SUCCESS);
}
int st_alsastopwrite(ft)
ft_t ft;
{
ioctl(fileno(ft->fp), SND_PCM_IOCTL_CHANNEL_DRAIN);
return(st_rawstopwrite(ft));
}
#endif /* HAVE_ALSA4/5 */
#endif /* HAVE_ALSA9 */
#define EMSGFMT "ALSA driver does not support %s %s output"
static int get_format(ft, formats, fmt)
ft_t ft;
int formats, *fmt;
{
if (ft->info.size == -1) {
if ((formats & SND_PCM_FMT_U8) || (formats & SND_PCM_FMT_S8))
ft->info.size = ST_SIZE_BYTE;
else
ft->info.size = ST_SIZE_WORD;
}
if (ft->info.encoding == -1) {
if ((formats & SND_PCM_FMT_S16) || (formats & SND_PCM_FMT_S8))
ft->info.encoding = ST_ENCODING_SIGN2;
else
ft->info.encoding = ST_ENCODING_UNSIGNED;
}
if (ft->info.size == ST_SIZE_BYTE) {
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(formats & SND_PCM_FMT_S8)) {
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed byte samples");
return ST_EOF;
}
*fmt = SND_PCM_SFMT_S8;
break;
case ST_ENCODING_UNSIGNED:
if (!(formats & SND_PCM_FMT_U8)) {
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned byte samples");
return ST_EOF;
}
*fmt = SND_PCM_SFMT_U8;
break;
default:
st_fail_errno(ft,ST_EFMT,EMSGFMT,st_encodings_str[(unsigned char)ft->info.encoding],"byte");
return ST_EOF;
break;
}
}
else if (ft->info.size == ST_SIZE_WORD) {
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(formats & SND_PCM_FMT_S16)) {
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed word samples");
return ST_EOF;
}
*fmt = SND_PCM_SFMT_S16_LE;
break;
case ST_ENCODING_UNSIGNED:
if (!(formats & SND_PCM_FMT_U16)) {
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned word samples");
return ST_EOF;
}
*fmt = SND_PCM_SFMT_U16_LE;
break;
default:
st_fail_errno(ft,ST_EFMT,EMSGFMT,st_encodings_str[(unsigned char)ft->info.encoding],"word");
return ST_EOF;
break;
}
}
else {
st_fail_errno(ft,ST_EFMT,EMSGFMT,st_encodings_str[(unsigned char)ft->info.encoding],st_sizes_str[(unsigned char)ft->info.size]);
return ST_EOF;
}
return 0;
}
st_ssize_t st_alsaread(ft_t ft, st_sample_t *buf, st_ssize_t nsamp)
{
st_ssize_t len;
len = st_rawread(ft, buf, nsamp);
#if HAVE_ALSA9
/* ALSA 0.9 and above require that we detects underruns and
* reset the driver if it occurs.
*/
if (len != nsamp)
{
/* Reset the driver. A future enhancement would be to
* fill up the empty spots in the buffer (starting at
* nsamp - len). But I'm being lazy (cbagwell) and just
* returning with a partial buffer.
*/
ioctl(fileno(ft->fp), SNDRV_PCM_IOCTL_PREPARE);
/* Raw routines use eof flag to store when we've
* hit EOF or if an internal error occurs. The
* above ioctl is much like calling the stdio clearerr() function
* and so we should reset libst's flag as well. If the
* error condition is still really there, it will be
* detected on a future read.
*/
ft->file.eof = ST_SUCCESS;
}
#endif
return len;
}
st_ssize_t st_alsawrite(ft_t ft, st_sample_t *buf, st_ssize_t nsamp)
{
st_ssize_t len;
len = st_rawwrite(ft, buf, nsamp);
#if HAVE_ALSA9
/* ALSA 0.9 and above require that we detects overruns and
* reset the driver if it occurs.
*/
if (len != nsamp)
{
/* Reset the driver. A future enhancement would be to
* resend the remaining data (starting at (nsamp - len) in the buffer).
* But since we've already lost some data, I'm being lazy
* and letting a little more data be lost as well.
*/
ioctl(fileno(ft->fp), SNDRV_PCM_IOCTL_PREPARE);
/* Raw routines use eof flag to store when an internal error
* the above ioctl is much like calling the stdio clearerr() function
* and so we should reset libst's flag as well. If the
* error condition is still really there, it will be
* detected on a future write.
*/
ft->file.eof = ST_SUCCESS;
}
#endif
return len;
}
#endif /* HAVE_ALSA */