2 * PCM Plug-In shared (kernel/library) code
3 * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
4 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Library General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27 #include <linux/slab.h>
28 #include <linux/time.h>
29 #include <linux/vmalloc.h>
30 #include <sound/core.h>
31 #include <sound/pcm.h>
32 #include <sound/pcm_params.h>
33 #include "pcm_plugin.h"
35 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
36 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
39 * because some cards might have rates "very close", we ignore
40 * all "resampling" requests within +-5%
42 static int rate_match(unsigned int src_rate
, unsigned int dst_rate
)
44 unsigned int low
= (src_rate
* 95) / 100;
45 unsigned int high
= (src_rate
* 105) / 100;
46 return dst_rate
>= low
&& dst_rate
<= high
;
49 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin
*plugin
, snd_pcm_uframes_t frames
)
51 struct snd_pcm_plugin_format
*format
;
55 struct snd_pcm_plugin_channel
*c
;
57 if (plugin
->stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
58 format
= &plugin
->src_format
;
60 format
= &plugin
->dst_format
;
62 if ((width
= snd_pcm_format_physical_width(format
->format
)) < 0)
64 size
= frames
* format
->channels
* width
;
65 if (snd_BUG_ON(size
% 8))
68 if (plugin
->buf_frames
< frames
) {
70 plugin
->buf
= vmalloc(size
);
71 plugin
->buf_frames
= frames
;
74 plugin
->buf_frames
= 0;
77 c
= plugin
->buf_channels
;
78 if (plugin
->access
== SNDRV_PCM_ACCESS_RW_INTERLEAVED
) {
79 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
83 c
->area
.addr
= plugin
->buf
;
84 c
->area
.first
= channel
* width
;
85 c
->area
.step
= format
->channels
* width
;
87 } else if (plugin
->access
== SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
) {
88 if (snd_BUG_ON(size
% format
->channels
))
90 size
/= format
->channels
;
91 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
95 c
->area
.addr
= plugin
->buf
+ (channel
* size
);
104 int snd_pcm_plug_alloc(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t frames
)
107 if (snd_BUG_ON(!snd_pcm_plug_first(plug
)))
109 if (snd_pcm_plug_stream(plug
) == SNDRV_PCM_STREAM_PLAYBACK
) {
110 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_first(plug
);
111 while (plugin
->next
) {
112 if (plugin
->dst_frames
)
113 frames
= plugin
->dst_frames(plugin
, frames
);
114 if (snd_BUG_ON(frames
<= 0))
116 plugin
= plugin
->next
;
117 err
= snd_pcm_plugin_alloc(plugin
, frames
);
122 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_last(plug
);
123 while (plugin
->prev
) {
124 if (plugin
->src_frames
)
125 frames
= plugin
->src_frames(plugin
, frames
);
126 if (snd_BUG_ON(frames
<= 0))
128 plugin
= plugin
->prev
;
129 err
= snd_pcm_plugin_alloc(plugin
, frames
);
138 snd_pcm_sframes_t
snd_pcm_plugin_client_channels(struct snd_pcm_plugin
*plugin
,
139 snd_pcm_uframes_t frames
,
140 struct snd_pcm_plugin_channel
**channels
)
142 *channels
= plugin
->buf_channels
;
146 int snd_pcm_plugin_build(struct snd_pcm_substream
*plug
,
148 struct snd_pcm_plugin_format
*src_format
,
149 struct snd_pcm_plugin_format
*dst_format
,
151 struct snd_pcm_plugin
**ret
)
153 struct snd_pcm_plugin
*plugin
;
154 unsigned int channels
;
156 if (snd_BUG_ON(!plug
))
158 if (snd_BUG_ON(!src_format
|| !dst_format
))
160 plugin
= kzalloc(sizeof(*plugin
) + extra
, GFP_KERNEL
);
165 plugin
->stream
= snd_pcm_plug_stream(plug
);
166 plugin
->access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
167 plugin
->src_format
= *src_format
;
168 plugin
->src_width
= snd_pcm_format_physical_width(src_format
->format
);
169 snd_BUG_ON(plugin
->src_width
<= 0);
170 plugin
->dst_format
= *dst_format
;
171 plugin
->dst_width
= snd_pcm_format_physical_width(dst_format
->format
);
172 snd_BUG_ON(plugin
->dst_width
<= 0);
173 if (plugin
->stream
== SNDRV_PCM_STREAM_PLAYBACK
)
174 channels
= src_format
->channels
;
176 channels
= dst_format
->channels
;
177 plugin
->buf_channels
= kcalloc(channels
, sizeof(*plugin
->buf_channels
), GFP_KERNEL
);
178 if (plugin
->buf_channels
== NULL
) {
179 snd_pcm_plugin_free(plugin
);
182 plugin
->client_channels
= snd_pcm_plugin_client_channels
;
187 int snd_pcm_plugin_free(struct snd_pcm_plugin
*plugin
)
191 if (plugin
->private_free
)
192 plugin
->private_free(plugin
);
193 kfree(plugin
->buf_channels
);
199 snd_pcm_sframes_t
snd_pcm_plug_client_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t drv_frames
)
201 struct snd_pcm_plugin
*plugin
, *plugin_prev
, *plugin_next
;
202 int stream
= snd_pcm_plug_stream(plug
);
204 if (snd_BUG_ON(!plug
))
208 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
209 plugin
= snd_pcm_plug_last(plug
);
210 while (plugin
&& drv_frames
> 0) {
211 plugin_prev
= plugin
->prev
;
212 if (plugin
->src_frames
)
213 drv_frames
= plugin
->src_frames(plugin
, drv_frames
);
214 plugin
= plugin_prev
;
216 } else if (stream
== SNDRV_PCM_STREAM_CAPTURE
) {
217 plugin
= snd_pcm_plug_first(plug
);
218 while (plugin
&& drv_frames
> 0) {
219 plugin_next
= plugin
->next
;
220 if (plugin
->dst_frames
)
221 drv_frames
= plugin
->dst_frames(plugin
, drv_frames
);
222 plugin
= plugin_next
;
229 snd_pcm_sframes_t
snd_pcm_plug_slave_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t clt_frames
)
231 struct snd_pcm_plugin
*plugin
, *plugin_prev
, *plugin_next
;
232 snd_pcm_sframes_t frames
;
233 int stream
= snd_pcm_plug_stream(plug
);
235 if (snd_BUG_ON(!plug
))
240 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
241 plugin
= snd_pcm_plug_first(plug
);
242 while (plugin
&& frames
> 0) {
243 plugin_next
= plugin
->next
;
244 if (plugin
->dst_frames
) {
245 frames
= plugin
->dst_frames(plugin
, frames
);
249 plugin
= plugin_next
;
251 } else if (stream
== SNDRV_PCM_STREAM_CAPTURE
) {
252 plugin
= snd_pcm_plug_last(plug
);
254 plugin_prev
= plugin
->prev
;
255 if (plugin
->src_frames
) {
256 frames
= plugin
->src_frames(plugin
, frames
);
260 plugin
= plugin_prev
;
267 static int snd_pcm_plug_formats(struct snd_mask
*mask
, snd_pcm_format_t format
)
269 struct snd_mask formats
= *mask
;
270 u64 linfmts
= (SNDRV_PCM_FMTBIT_U8
| SNDRV_PCM_FMTBIT_S8
|
271 SNDRV_PCM_FMTBIT_U16_LE
| SNDRV_PCM_FMTBIT_S16_LE
|
272 SNDRV_PCM_FMTBIT_U16_BE
| SNDRV_PCM_FMTBIT_S16_BE
|
273 SNDRV_PCM_FMTBIT_U24_LE
| SNDRV_PCM_FMTBIT_S24_LE
|
274 SNDRV_PCM_FMTBIT_U24_BE
| SNDRV_PCM_FMTBIT_S24_BE
|
275 SNDRV_PCM_FMTBIT_U24_3LE
| SNDRV_PCM_FMTBIT_S24_3LE
|
276 SNDRV_PCM_FMTBIT_U24_3BE
| SNDRV_PCM_FMTBIT_S24_3BE
|
277 SNDRV_PCM_FMTBIT_U32_LE
| SNDRV_PCM_FMTBIT_S32_LE
|
278 SNDRV_PCM_FMTBIT_U32_BE
| SNDRV_PCM_FMTBIT_S32_BE
);
279 snd_mask_set(&formats
, (__force
int)SNDRV_PCM_FORMAT_MU_LAW
);
281 if (formats
.bits
[0] & (u32
)linfmts
)
282 formats
.bits
[0] |= (u32
)linfmts
;
283 if (formats
.bits
[1] & (u32
)(linfmts
>> 32))
284 formats
.bits
[1] |= (u32
)(linfmts
>> 32);
285 return snd_mask_test(&formats
, (__force
int)format
);
288 static snd_pcm_format_t preferred_formats
[] = {
289 SNDRV_PCM_FORMAT_S16_LE
,
290 SNDRV_PCM_FORMAT_S16_BE
,
291 SNDRV_PCM_FORMAT_U16_LE
,
292 SNDRV_PCM_FORMAT_U16_BE
,
293 SNDRV_PCM_FORMAT_S24_3LE
,
294 SNDRV_PCM_FORMAT_S24_3BE
,
295 SNDRV_PCM_FORMAT_U24_3LE
,
296 SNDRV_PCM_FORMAT_U24_3BE
,
297 SNDRV_PCM_FORMAT_S24_LE
,
298 SNDRV_PCM_FORMAT_S24_BE
,
299 SNDRV_PCM_FORMAT_U24_LE
,
300 SNDRV_PCM_FORMAT_U24_BE
,
301 SNDRV_PCM_FORMAT_S32_LE
,
302 SNDRV_PCM_FORMAT_S32_BE
,
303 SNDRV_PCM_FORMAT_U32_LE
,
304 SNDRV_PCM_FORMAT_U32_BE
,
309 snd_pcm_format_t
snd_pcm_plug_slave_format(snd_pcm_format_t format
,
310 struct snd_mask
*format_mask
)
314 if (snd_mask_test(format_mask
, (__force
int)format
))
316 if (!snd_pcm_plug_formats(format_mask
, format
))
317 return (__force snd_pcm_format_t
)-EINVAL
;
318 if (snd_pcm_format_linear(format
)) {
319 unsigned int width
= snd_pcm_format_width(format
);
320 int unsignd
= snd_pcm_format_unsigned(format
) > 0;
321 int big
= snd_pcm_format_big_endian(format
) > 0;
322 unsigned int badness
, best
= -1;
323 snd_pcm_format_t best_format
= (__force snd_pcm_format_t
)-1;
324 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); i
++) {
325 snd_pcm_format_t f
= preferred_formats
[i
];
327 if (!snd_mask_test(format_mask
, (__force
int)f
))
329 w
= snd_pcm_format_width(f
);
333 badness
= width
- w
+ 32;
334 badness
+= snd_pcm_format_unsigned(f
) != unsignd
;
335 badness
+= snd_pcm_format_big_endian(f
) != big
;
336 if (badness
< best
) {
341 if ((__force
int)best_format
>= 0)
344 return (__force snd_pcm_format_t
)-EINVAL
;
347 case SNDRV_PCM_FORMAT_MU_LAW
:
348 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); ++i
) {
349 snd_pcm_format_t format1
= preferred_formats
[i
];
350 if (snd_mask_test(format_mask
, (__force
int)format1
))
354 return (__force snd_pcm_format_t
)-EINVAL
;
359 int snd_pcm_plug_format_plugins(struct snd_pcm_substream
*plug
,
360 struct snd_pcm_hw_params
*params
,
361 struct snd_pcm_hw_params
*slave_params
)
363 struct snd_pcm_plugin_format tmpformat
;
364 struct snd_pcm_plugin_format dstformat
;
365 struct snd_pcm_plugin_format srcformat
;
366 snd_pcm_access_t src_access
, dst_access
;
367 struct snd_pcm_plugin
*plugin
= NULL
;
369 int stream
= snd_pcm_plug_stream(plug
);
370 int slave_interleaved
= (params_channels(slave_params
) == 1 ||
371 params_access(slave_params
) == SNDRV_PCM_ACCESS_RW_INTERLEAVED
);
374 case SNDRV_PCM_STREAM_PLAYBACK
:
375 dstformat
.format
= params_format(slave_params
);
376 dstformat
.rate
= params_rate(slave_params
);
377 dstformat
.channels
= params_channels(slave_params
);
378 srcformat
.format
= params_format(params
);
379 srcformat
.rate
= params_rate(params
);
380 srcformat
.channels
= params_channels(params
);
381 src_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
382 dst_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
383 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
385 case SNDRV_PCM_STREAM_CAPTURE
:
386 dstformat
.format
= params_format(params
);
387 dstformat
.rate
= params_rate(params
);
388 dstformat
.channels
= params_channels(params
);
389 srcformat
.format
= params_format(slave_params
);
390 srcformat
.rate
= params_rate(slave_params
);
391 srcformat
.channels
= params_channels(slave_params
);
392 src_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
393 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
394 dst_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
400 tmpformat
= srcformat
;
402 pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
406 pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
411 /* Format change (linearization) */
412 if (! rate_match(srcformat
.rate
, dstformat
.rate
) &&
413 ! snd_pcm_format_linear(srcformat
.format
)) {
414 if (srcformat
.format
!= SNDRV_PCM_FORMAT_MU_LAW
)
416 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
417 err
= snd_pcm_plugin_build_mulaw(plug
,
418 &srcformat
, &tmpformat
,
422 err
= snd_pcm_plugin_append(plugin
);
424 snd_pcm_plugin_free(plugin
);
427 srcformat
= tmpformat
;
428 src_access
= dst_access
;
431 /* channels reduction */
432 if (srcformat
.channels
> dstformat
.channels
) {
433 tmpformat
.channels
= dstformat
.channels
;
434 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
435 pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
438 err
= snd_pcm_plugin_append(plugin
);
440 snd_pcm_plugin_free(plugin
);
443 srcformat
= tmpformat
;
444 src_access
= dst_access
;
447 /* rate resampling */
448 if (!rate_match(srcformat
.rate
, dstformat
.rate
)) {
449 if (srcformat
.format
!= SNDRV_PCM_FORMAT_S16
) {
450 /* convert to S16 for resampling */
451 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
452 err
= snd_pcm_plugin_build_linear(plug
,
453 &srcformat
, &tmpformat
,
457 err
= snd_pcm_plugin_append(plugin
);
459 snd_pcm_plugin_free(plugin
);
462 srcformat
= tmpformat
;
463 src_access
= dst_access
;
465 tmpformat
.rate
= dstformat
.rate
;
466 err
= snd_pcm_plugin_build_rate(plug
,
467 &srcformat
, &tmpformat
,
469 pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat
.rate
, tmpformat
.rate
, err
);
472 err
= snd_pcm_plugin_append(plugin
);
474 snd_pcm_plugin_free(plugin
);
477 srcformat
= tmpformat
;
478 src_access
= dst_access
;
482 if (srcformat
.format
!= dstformat
.format
) {
483 tmpformat
.format
= dstformat
.format
;
484 if (srcformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
||
485 tmpformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
) {
486 err
= snd_pcm_plugin_build_mulaw(plug
,
487 &srcformat
, &tmpformat
,
490 else if (snd_pcm_format_linear(srcformat
.format
) &&
491 snd_pcm_format_linear(tmpformat
.format
)) {
492 err
= snd_pcm_plugin_build_linear(plug
,
493 &srcformat
, &tmpformat
,
498 pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat
.format
, tmpformat
.format
, err
);
501 err
= snd_pcm_plugin_append(plugin
);
503 snd_pcm_plugin_free(plugin
);
506 srcformat
= tmpformat
;
507 src_access
= dst_access
;
510 /* channels extension */
511 if (srcformat
.channels
< dstformat
.channels
) {
512 tmpformat
.channels
= dstformat
.channels
;
513 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
514 pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
517 err
= snd_pcm_plugin_append(plugin
);
519 snd_pcm_plugin_free(plugin
);
522 srcformat
= tmpformat
;
523 src_access
= dst_access
;
527 if (src_access
!= dst_access
) {
528 err
= snd_pcm_plugin_build_copy(plug
,
532 pdprintf("interleave change (copy: returns %i)\n", err
);
535 err
= snd_pcm_plugin_append(plugin
);
537 snd_pcm_plugin_free(plugin
);
545 snd_pcm_sframes_t
snd_pcm_plug_client_channels_buf(struct snd_pcm_substream
*plug
,
547 snd_pcm_uframes_t count
,
548 struct snd_pcm_plugin_channel
**channels
)
550 struct snd_pcm_plugin
*plugin
;
551 struct snd_pcm_plugin_channel
*v
;
552 struct snd_pcm_plugin_format
*format
;
553 int width
, nchannels
, channel
;
554 int stream
= snd_pcm_plug_stream(plug
);
556 if (snd_BUG_ON(!buf
))
558 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
559 plugin
= snd_pcm_plug_first(plug
);
560 format
= &plugin
->src_format
;
562 plugin
= snd_pcm_plug_last(plug
);
563 format
= &plugin
->dst_format
;
565 v
= plugin
->buf_channels
;
567 if ((width
= snd_pcm_format_physical_width(format
->format
)) < 0)
569 nchannels
= format
->channels
;
570 if (snd_BUG_ON(plugin
->access
!= SNDRV_PCM_ACCESS_RW_INTERLEAVED
&&
571 format
->channels
> 1))
573 for (channel
= 0; channel
< nchannels
; channel
++, v
++) {
576 v
->wanted
= (stream
== SNDRV_PCM_STREAM_CAPTURE
);
578 v
->area
.first
= channel
* width
;
579 v
->area
.step
= nchannels
* width
;
584 snd_pcm_sframes_t
snd_pcm_plug_write_transfer(struct snd_pcm_substream
*plug
, struct snd_pcm_plugin_channel
*src_channels
, snd_pcm_uframes_t size
)
586 struct snd_pcm_plugin
*plugin
, *next
;
587 struct snd_pcm_plugin_channel
*dst_channels
;
589 snd_pcm_sframes_t frames
= size
;
591 plugin
= snd_pcm_plug_first(plug
);
592 while (plugin
&& frames
> 0) {
593 if ((next
= plugin
->next
) != NULL
) {
594 snd_pcm_sframes_t frames1
= frames
;
595 if (plugin
->dst_frames
)
596 frames1
= plugin
->dst_frames(plugin
, frames
);
597 if ((err
= next
->client_channels(next
, frames1
, &dst_channels
)) < 0) {
600 if (err
!= frames1
) {
602 if (plugin
->src_frames
)
603 frames
= plugin
->src_frames(plugin
, frames1
);
607 pdprintf("write plugin: %s, %li\n", plugin
->name
, frames
);
608 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
610 src_channels
= dst_channels
;
613 return snd_pcm_plug_client_size(plug
, frames
);
616 snd_pcm_sframes_t
snd_pcm_plug_read_transfer(struct snd_pcm_substream
*plug
, struct snd_pcm_plugin_channel
*dst_channels_final
, snd_pcm_uframes_t size
)
618 struct snd_pcm_plugin
*plugin
, *next
;
619 struct snd_pcm_plugin_channel
*src_channels
, *dst_channels
;
620 snd_pcm_sframes_t frames
= size
;
623 frames
= snd_pcm_plug_slave_size(plug
, frames
);
628 plugin
= snd_pcm_plug_first(plug
);
629 while (plugin
&& frames
> 0) {
630 if ((next
= plugin
->next
) != NULL
) {
631 if ((err
= plugin
->client_channels(plugin
, frames
, &dst_channels
)) < 0) {
636 dst_channels
= dst_channels_final
;
638 pdprintf("read plugin: %s, %li\n", plugin
->name
, frames
);
639 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
642 src_channels
= dst_channels
;
647 int snd_pcm_area_silence(const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
648 size_t samples
, snd_pcm_format_t format
)
650 /* FIXME: sub byte resolution and odd dst_offset */
652 unsigned int dst_step
;
654 const unsigned char *silence
;
657 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
658 width
= snd_pcm_format_physical_width(format
);
661 if (dst_area
->step
== (unsigned int) width
&& width
>= 8)
662 return snd_pcm_format_set_silence(format
, dst
, samples
);
663 silence
= snd_pcm_format_silence_64(format
);
666 dst_step
= dst_area
->step
/ 8;
669 int dstbit
= dst_area
->first
% 8;
670 int dstbit_step
= dst_area
->step
% 8;
671 while (samples
-- > 0) {
677 dstbit
+= dstbit_step
;
685 while (samples
-- > 0) {
686 memcpy(dst
, silence
, width
);
693 int snd_pcm_area_copy(const struct snd_pcm_channel_area
*src_area
, size_t src_offset
,
694 const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
695 size_t samples
, snd_pcm_format_t format
)
697 /* FIXME: sub byte resolution and odd dst_offset */
700 int src_step
, dst_step
;
701 src
= src_area
->addr
+ (src_area
->first
+ src_area
->step
* src_offset
) / 8;
703 return snd_pcm_area_silence(dst_area
, dst_offset
, samples
, format
);
704 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
707 width
= snd_pcm_format_physical_width(format
);
710 if (src_area
->step
== (unsigned int) width
&&
711 dst_area
->step
== (unsigned int) width
&& width
>= 8) {
712 size_t bytes
= samples
* width
/ 8;
713 memcpy(dst
, src
, bytes
);
716 src_step
= src_area
->step
/ 8;
717 dst_step
= dst_area
->step
/ 8;
720 int srcbit
= src_area
->first
% 8;
721 int srcbit_step
= src_area
->step
% 8;
722 int dstbit
= dst_area
->first
% 8;
723 int dstbit_step
= dst_area
->step
% 8;
724 while (samples
-- > 0) {
725 unsigned char srcval
;
727 srcval
= *src
& 0x0f;
729 srcval
= (*src
& 0xf0) >> 4;
731 *dst
= (*dst
& 0xf0) | srcval
;
733 *dst
= (*dst
& 0x0f) | (srcval
<< 4);
735 srcbit
+= srcbit_step
;
741 dstbit
+= dstbit_step
;
749 while (samples
-- > 0) {
750 memcpy(dst
, src
, width
);