mirror of
https://github.com/alsa-project/alsa-lib.git
synced 2025-10-29 05:40:25 -04:00
PCM loopback API improved and added back the functionality.
Some mmap() changes for the OSS emulation.
This commit is contained in:
Jaroslav Kysela
parent
3239ca9940
commit
f5e461caa3
4 changed files with 182 additions and 34 deletions
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@ -6,7 +6,7 @@
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****************************************************************************/
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typedef struct snd_mixer_callbacks {
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void *private_data; /* should be used by an application */
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void *private_data; /* should be used with an application */
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void (*rebuild) (void *private_data);
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void (*element) (void *private_data, int cmd, snd_mixer_eid_t *eid);
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void (*group) (void *private_data, int cmd, snd_mixer_gid_t *gid);
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@ -144,13 +144,23 @@ int snd_pcm_plugin_build_voices(int src_format, int src_voices,
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extern "C" {
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#endif
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int snd_pcm_loopback_open(snd_pcm_loopback_t **handle, int card, int device, int subchn, int mode);
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typedef struct snd_pcm_loopback_callbacks {
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void *private_data; /* should be used with an application */
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size_t max_buffer_size; /* zero = default (64kB) */
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void (*data) (void *private_data, char *buffer, size_t count);
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void (*position_change) (void *private_data, unsigned int pos);
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void (*format_change) (void *private_data, snd_pcm_format_t *format);
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char *reserved[32]; /* reserved for the future use - must be NULL!!! */
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} snd_pcm_loopback_callbacks_t;
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int snd_pcm_loopback_open(snd_pcm_loopback_t **handle, int card, int device, int subdev, int mode);
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int snd_pcm_loopback_close(snd_pcm_loopback_t *handle);
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int snd_pcm_loopback_file_descriptor(snd_pcm_loopback_t *handle);
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int snd_pcm_loopback_block_mode(snd_pcm_loopback_t *handle, int enable);
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int snd_pcm_loopback_stream_mode(snd_pcm_loopback_t *handle, int mode);
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int snd_pcm_loopback_format(snd_pcm_loopback_t *handle, snd_pcm_format_t * format);
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ssize_t snd_pcm_loopback_read(snd_pcm_loopback_t *handle, void *buffer, size_t size);
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int snd_pcm_loopback_status(snd_pcm_loopback_t *handle, snd_pcm_loopback_status_t * status);
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ssize_t snd_pcm_loopback_read(snd_pcm_loopback_t *handle, snd_pcm_loopback_callbacks_t * callbacks);
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#ifdef __cplusplus
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}
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@ -29,13 +29,16 @@
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#include "asoundlib.h"
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#define SND_FILE_PCM_LB "/proc/asound/%i/pcmloopD%iS%i%s"
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#define SND_PCM_LB_VERSION_MAX SND_PROTOCOL_VERSION( 1, 0, 0 )
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#define SND_PCM_LB_VERSION_MAX SND_PROTOCOL_VERSION(2, 0, 0)
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struct snd_pcm_loopback {
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int card;
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int device;
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int fd;
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} ;
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long mode;
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size_t buffer_size;
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char *buffer;
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};
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int snd_pcm_loopback_open(snd_pcm_loopback_t **handle, int card, int device, int subchn, int mode)
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{
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@ -70,39 +73,35 @@ int snd_pcm_loopback_open(snd_pcm_loopback_t **handle, int card, int device, int
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lb->card = card;
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lb->device = device;
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lb->fd = fd;
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lb->mode = SND_PCM_LB_STREAM_MODE_RAW;
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*handle = lb;
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return 0;
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}
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int snd_pcm_loopback_close(snd_pcm_loopback_t *handle)
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int snd_pcm_loopback_close(snd_pcm_loopback_t *lb)
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{
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snd_pcm_loopback_t *lb;
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int res;
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lb = handle;
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if (!lb)
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return -EINVAL;
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if (lb->buffer)
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free(lb->buffer);
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res = close(lb->fd) < 0 ? -errno : 0;
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free(lb);
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return res;
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}
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int snd_pcm_loopback_file_descriptor(snd_pcm_loopback_t *handle)
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int snd_pcm_loopback_file_descriptor(snd_pcm_loopback_t *lb)
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{
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snd_pcm_loopback_t *lb;
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lb = handle;
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if (!lb)
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return -EINVAL;
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return lb->fd;
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}
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int snd_pcm_loopback_block_mode(snd_pcm_loopback_t *handle, int enable)
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int snd_pcm_loopback_block_mode(snd_pcm_loopback_t *lb, int enable)
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{
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snd_pcm_loopback_t *lb;
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long flags;
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lb = handle;
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if (!lb)
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return -EINVAL;
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if ((flags = fcntl(lb->fd, F_GETFL)) < 0)
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@ -116,24 +115,19 @@ int snd_pcm_loopback_block_mode(snd_pcm_loopback_t *handle, int enable)
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return 0;
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}
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int snd_pcm_loopback_stream_mode(snd_pcm_loopback_t *handle, int mode)
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int snd_pcm_loopback_stream_mode(snd_pcm_loopback_t *lb, int mode)
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{
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snd_pcm_loopback_t *lb;
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long lmode = mode;
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lb = handle;
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if (!lb)
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if (!lb || (mode != SND_PCM_LB_STREAM_MODE_RAW &&
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mode != SND_PCM_LB_STREAM_MODE_PACKET))
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return -EINVAL;
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if (ioctl(lb->fd, SND_PCM_LB_IOCTL_STREAM_MODE, &lmode) < 0)
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lb->mode = mode;
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if (ioctl(lb->fd, SND_PCM_LB_IOCTL_STREAM_MODE, &lb->mode) < 0)
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return -errno;
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return 0;
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}
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int snd_pcm_loopback_format(snd_pcm_loopback_t *handle, snd_pcm_format_t * format)
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int snd_pcm_loopback_format(snd_pcm_loopback_t *lb, snd_pcm_format_t * format)
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{
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snd_pcm_loopback_t *lb;
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lb = handle;
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if (!lb)
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return -EINVAL;
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if (ioctl(lb->fd, SND_PCM_LB_IOCTL_FORMAT, format) < 0)
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@ -141,16 +135,101 @@ int snd_pcm_loopback_format(snd_pcm_loopback_t *handle, snd_pcm_format_t * forma
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return 0;
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}
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ssize_t snd_pcm_loopback_read(snd_pcm_loopback_t *handle, void *buffer, size_t size)
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int snd_pcm_loopback_status(snd_pcm_loopback_t *lb, snd_pcm_loopback_status_t * status)
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{
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snd_pcm_loopback_t *lb;
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ssize_t result;
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lb = handle;
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if (!lb)
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return -EINVAL;
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result = read(lb->fd, buffer, size);
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if (result < 0)
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if (ioctl(lb->fd, SND_PCM_LB_IOCTL_FORMAT, status) < 0)
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return -errno;
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return 0;
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}
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ssize_t snd_pcm_loopback_read(snd_pcm_loopback_t *lb, snd_pcm_loopback_callbacks_t *callbacks)
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{
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ssize_t result = 0, res, count;
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size_t size;
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char *buf;
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snd_pcm_loopback_header_t header;
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if (!lb || !callbacks)
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return -EINVAL;
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if (callbacks->max_buffer_size == 0)
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size = 64 * 1024;
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else
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size = callbacks->max_buffer_size < 16 ? 16 : callbacks->max_buffer_size;
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while (1) {
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if (lb->mode == SND_PCM_LB_STREAM_MODE_RAW) {
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header.size = size;
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header.type = SND_PCM_LB_TYPE_DATA;
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} else {
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res = read(lb->fd, &header, sizeof(header));
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if (res < 0)
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return -errno;
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if (res == 0)
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break;
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if (res != sizeof(header))
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return -EBADFD;
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result += res;
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}
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switch (header.type) {
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case SND_PCM_LB_TYPE_DATA:
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if (lb->buffer_size < size) {
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buf = (char *) realloc(lb->buffer, size);
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if (buf == NULL)
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return -ENOMEM;
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lb->buffer = buf;
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lb->buffer_size = size;
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} else {
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buf = lb->buffer;
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}
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while (header.size > 0) {
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count = header.size;
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if (count > size)
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count = size;
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res = read(lb->fd, buf, count);
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if (res < 0)
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return -errno;
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result += res;
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if (lb->mode == SND_PCM_LB_STREAM_MODE_PACKET && res != count)
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return -EBADFD;
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if (res == 0)
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break;
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if (callbacks->data)
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callbacks->data(callbacks->private_data, buf, res);
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if (res < count && lb->mode == SND_PCM_LB_STREAM_MODE_RAW)
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break;
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header.size -= res;
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}
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break;
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case SND_PCM_LB_TYPE_FORMAT:
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{
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snd_pcm_format_t format;
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res = read(lb->fd, &format, sizeof(format));
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if (res < 0)
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return -errno;
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result += res;
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if (res != sizeof(format))
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return -EBADFD;
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if (callbacks->format_change)
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callbacks->format_change(callbacks->private_data, &format);
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}
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break;
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case SND_PCM_LB_TYPE_POSITION:
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{
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unsigned int pos;
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res = read(lb->fd, &pos, sizeof(pos));
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if (res < 0)
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return -errno;
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result += res;
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if (res != sizeof(pos))
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return -EBADFD;
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if (callbacks->position_change)
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callbacks->position_change(callbacks->private_data, pos);
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}
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break;
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}
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}
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return result;
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}
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@ -3,16 +3,75 @@
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#include <string.h>
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#include "../include/asoundlib.h"
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#define CARD 0
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#define DEVICE 0
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#define SUBDEV 0
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#define MODE SND_PCM_LB_STREAM_MODE_PACKET
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static void show_format1(const char *prefix, snd_pcm_format_t *format)
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{
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printf("%sinterleave = %i, rate = %i, voices = %i, format = %i\n",
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prefix,
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format->interleave ? 1 : 0,
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format->rate,
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format->voices,
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format->format);
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}
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static void show_format(snd_pcm_loopback_t *handle)
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{
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snd_pcm_format_t format;
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int err;
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err = snd_pcm_loopback_format(handle, &format);
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if (err < 0) {
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fprintf(stderr, "format failed: %s\n", snd_strerror(err));
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exit(0);
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}
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show_format1("Format: ", &format);
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}
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static void data(void *private_data, char *buf, size_t count)
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{
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printf("DATA> count = %li\n", (long)count);
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}
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static void format_change(void *private_data, snd_pcm_format_t *format)
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{
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show_format1("Format change> ", format);
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}
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static void position_change(void *private_data, unsigned int pos)
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{
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printf("Position change> %u\n", pos);
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}
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int main(int argc, char *argv[])
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{
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int err;
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ssize_t res;
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snd_pcm_loopback_t *handle;
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snd_pcm_loopback_callbacks_t callbacks;
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err = snd_pcm_loopback_open(&handle, 0, 0, SND_PCM_LB_OPEN_PLAYBACK);
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err = snd_pcm_loopback_open(&handle, CARD, DEVICE, SUBDEV, SND_PCM_LB_OPEN_PLAYBACK);
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if (err < 0) {
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fprintf(stderr, "open error: %s\n", snd_strerror(err));
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exit(0);
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}
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err = snd_pcm_loopback_stream_mode(handle, MODE);
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if (err < 0) {
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fprintf(stderr, "stream mode setup failed: %s\n", snd_strerror(err));
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exit(0);
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}
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show_format(handle);
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memset(&callbacks, 0, sizeof(callbacks));
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callbacks.data = data;
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callbacks.format_change = format_change;
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callbacks.position_change = position_change;
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while ((res = snd_pcm_loopback_read(handle, &callbacks)) >= 0) {
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if (res > 0)
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printf("Read ok.. - %i\n", res);
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}
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snd_pcm_loopback_close(handle);
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return 0;
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}
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