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 width
= snd_pcm_format_physical_width(format
->format
);
65 size
= array3_size(frames
, format
->channels
, width
);
66 /* check for too large period size once again */
67 if (size
> 1024 * 1024)
69 if (snd_BUG_ON(size
% 8))
72 if (plugin
->buf_frames
< frames
) {
74 plugin
->buf
= kvzalloc(size
, GFP_KERNEL
);
75 plugin
->buf_frames
= frames
;
78 plugin
->buf_frames
= 0;
81 c
= plugin
->buf_channels
;
82 if (plugin
->access
== SNDRV_PCM_ACCESS_RW_INTERLEAVED
) {
83 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
87 c
->area
.addr
= plugin
->buf
;
88 c
->area
.first
= channel
* width
;
89 c
->area
.step
= format
->channels
* width
;
91 } else if (plugin
->access
== SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
) {
92 if (snd_BUG_ON(size
% format
->channels
))
94 size
/= format
->channels
;
95 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
99 c
->area
.addr
= plugin
->buf
+ (channel
* size
);
101 c
->area
.step
= width
;
108 int snd_pcm_plug_alloc(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t frames
)
111 if (snd_BUG_ON(!snd_pcm_plug_first(plug
)))
113 if (snd_pcm_plug_stream(plug
) == SNDRV_PCM_STREAM_PLAYBACK
) {
114 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_first(plug
);
115 while (plugin
->next
) {
116 if (plugin
->dst_frames
)
117 frames
= plugin
->dst_frames(plugin
, frames
);
118 if ((snd_pcm_sframes_t
)frames
<= 0)
120 plugin
= plugin
->next
;
121 err
= snd_pcm_plugin_alloc(plugin
, frames
);
126 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_last(plug
);
127 while (plugin
->prev
) {
128 if (plugin
->src_frames
)
129 frames
= plugin
->src_frames(plugin
, frames
);
130 if ((snd_pcm_sframes_t
)frames
<= 0)
132 plugin
= plugin
->prev
;
133 err
= snd_pcm_plugin_alloc(plugin
, frames
);
142 snd_pcm_sframes_t
snd_pcm_plugin_client_channels(struct snd_pcm_plugin
*plugin
,
143 snd_pcm_uframes_t frames
,
144 struct snd_pcm_plugin_channel
**channels
)
146 *channels
= plugin
->buf_channels
;
150 int snd_pcm_plugin_build(struct snd_pcm_substream
*plug
,
152 struct snd_pcm_plugin_format
*src_format
,
153 struct snd_pcm_plugin_format
*dst_format
,
155 struct snd_pcm_plugin
**ret
)
157 struct snd_pcm_plugin
*plugin
;
158 unsigned int channels
;
160 if (snd_BUG_ON(!plug
))
162 if (snd_BUG_ON(!src_format
|| !dst_format
))
164 plugin
= kzalloc(sizeof(*plugin
) + extra
, GFP_KERNEL
);
169 plugin
->stream
= snd_pcm_plug_stream(plug
);
170 plugin
->access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
171 plugin
->src_format
= *src_format
;
172 plugin
->src_width
= snd_pcm_format_physical_width(src_format
->format
);
173 snd_BUG_ON(plugin
->src_width
<= 0);
174 plugin
->dst_format
= *dst_format
;
175 plugin
->dst_width
= snd_pcm_format_physical_width(dst_format
->format
);
176 snd_BUG_ON(plugin
->dst_width
<= 0);
177 if (plugin
->stream
== SNDRV_PCM_STREAM_PLAYBACK
)
178 channels
= src_format
->channels
;
180 channels
= dst_format
->channels
;
181 plugin
->buf_channels
= kcalloc(channels
, sizeof(*plugin
->buf_channels
), GFP_KERNEL
);
182 if (plugin
->buf_channels
== NULL
) {
183 snd_pcm_plugin_free(plugin
);
186 plugin
->client_channels
= snd_pcm_plugin_client_channels
;
191 int snd_pcm_plugin_free(struct snd_pcm_plugin
*plugin
)
195 if (plugin
->private_free
)
196 plugin
->private_free(plugin
);
197 kfree(plugin
->buf_channels
);
203 static snd_pcm_sframes_t
calc_dst_frames(struct snd_pcm_substream
*plug
,
204 snd_pcm_sframes_t frames
,
207 struct snd_pcm_plugin
*plugin
, *plugin_next
;
209 plugin
= snd_pcm_plug_first(plug
);
210 while (plugin
&& frames
> 0) {
211 plugin_next
= plugin
->next
;
212 if (check_size
&& plugin
->buf_frames
&&
213 frames
> plugin
->buf_frames
)
214 frames
= plugin
->buf_frames
;
215 if (plugin
->dst_frames
) {
216 frames
= plugin
->dst_frames(plugin
, frames
);
220 plugin
= plugin_next
;
225 static snd_pcm_sframes_t
calc_src_frames(struct snd_pcm_substream
*plug
,
226 snd_pcm_sframes_t frames
,
229 struct snd_pcm_plugin
*plugin
, *plugin_prev
;
231 plugin
= snd_pcm_plug_last(plug
);
232 while (plugin
&& frames
> 0) {
233 plugin_prev
= plugin
->prev
;
234 if (plugin
->src_frames
) {
235 frames
= plugin
->src_frames(plugin
, frames
);
239 if (check_size
&& plugin
->buf_frames
&&
240 frames
> plugin
->buf_frames
)
241 frames
= plugin
->buf_frames
;
242 plugin
= plugin_prev
;
247 snd_pcm_sframes_t
snd_pcm_plug_client_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t drv_frames
)
249 if (snd_BUG_ON(!plug
))
251 switch (snd_pcm_plug_stream(plug
)) {
252 case SNDRV_PCM_STREAM_PLAYBACK
:
253 return calc_src_frames(plug
, drv_frames
, false);
254 case SNDRV_PCM_STREAM_CAPTURE
:
255 return calc_dst_frames(plug
, drv_frames
, false);
262 snd_pcm_sframes_t
snd_pcm_plug_slave_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t clt_frames
)
264 if (snd_BUG_ON(!plug
))
266 switch (snd_pcm_plug_stream(plug
)) {
267 case SNDRV_PCM_STREAM_PLAYBACK
:
268 return calc_dst_frames(plug
, clt_frames
, false);
269 case SNDRV_PCM_STREAM_CAPTURE
:
270 return calc_src_frames(plug
, clt_frames
, false);
277 static int snd_pcm_plug_formats(const struct snd_mask
*mask
,
278 snd_pcm_format_t format
)
280 struct snd_mask formats
= *mask
;
281 u64 linfmts
= (SNDRV_PCM_FMTBIT_U8
| SNDRV_PCM_FMTBIT_S8
|
282 SNDRV_PCM_FMTBIT_U16_LE
| SNDRV_PCM_FMTBIT_S16_LE
|
283 SNDRV_PCM_FMTBIT_U16_BE
| SNDRV_PCM_FMTBIT_S16_BE
|
284 SNDRV_PCM_FMTBIT_U24_LE
| SNDRV_PCM_FMTBIT_S24_LE
|
285 SNDRV_PCM_FMTBIT_U24_BE
| SNDRV_PCM_FMTBIT_S24_BE
|
286 SNDRV_PCM_FMTBIT_U24_3LE
| SNDRV_PCM_FMTBIT_S24_3LE
|
287 SNDRV_PCM_FMTBIT_U24_3BE
| SNDRV_PCM_FMTBIT_S24_3BE
|
288 SNDRV_PCM_FMTBIT_U32_LE
| SNDRV_PCM_FMTBIT_S32_LE
|
289 SNDRV_PCM_FMTBIT_U32_BE
| SNDRV_PCM_FMTBIT_S32_BE
);
290 snd_mask_set(&formats
, (__force
int)SNDRV_PCM_FORMAT_MU_LAW
);
292 if (formats
.bits
[0] & lower_32_bits(linfmts
))
293 formats
.bits
[0] |= lower_32_bits(linfmts
);
294 if (formats
.bits
[1] & upper_32_bits(linfmts
))
295 formats
.bits
[1] |= upper_32_bits(linfmts
);
296 return snd_mask_test(&formats
, (__force
int)format
);
299 static const snd_pcm_format_t preferred_formats
[] = {
300 SNDRV_PCM_FORMAT_S16_LE
,
301 SNDRV_PCM_FORMAT_S16_BE
,
302 SNDRV_PCM_FORMAT_U16_LE
,
303 SNDRV_PCM_FORMAT_U16_BE
,
304 SNDRV_PCM_FORMAT_S24_3LE
,
305 SNDRV_PCM_FORMAT_S24_3BE
,
306 SNDRV_PCM_FORMAT_U24_3LE
,
307 SNDRV_PCM_FORMAT_U24_3BE
,
308 SNDRV_PCM_FORMAT_S24_LE
,
309 SNDRV_PCM_FORMAT_S24_BE
,
310 SNDRV_PCM_FORMAT_U24_LE
,
311 SNDRV_PCM_FORMAT_U24_BE
,
312 SNDRV_PCM_FORMAT_S32_LE
,
313 SNDRV_PCM_FORMAT_S32_BE
,
314 SNDRV_PCM_FORMAT_U32_LE
,
315 SNDRV_PCM_FORMAT_U32_BE
,
320 snd_pcm_format_t
snd_pcm_plug_slave_format(snd_pcm_format_t format
,
321 const struct snd_mask
*format_mask
)
325 if (snd_mask_test(format_mask
, (__force
int)format
))
327 if (!snd_pcm_plug_formats(format_mask
, format
))
328 return (__force snd_pcm_format_t
)-EINVAL
;
329 if (snd_pcm_format_linear(format
)) {
330 unsigned int width
= snd_pcm_format_width(format
);
331 int unsignd
= snd_pcm_format_unsigned(format
) > 0;
332 int big
= snd_pcm_format_big_endian(format
) > 0;
333 unsigned int badness
, best
= -1;
334 snd_pcm_format_t best_format
= (__force snd_pcm_format_t
)-1;
335 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); i
++) {
336 snd_pcm_format_t f
= preferred_formats
[i
];
338 if (!snd_mask_test(format_mask
, (__force
int)f
))
340 w
= snd_pcm_format_width(f
);
344 badness
= width
- w
+ 32;
345 badness
+= snd_pcm_format_unsigned(f
) != unsignd
;
346 badness
+= snd_pcm_format_big_endian(f
) != big
;
347 if (badness
< best
) {
352 if ((__force
int)best_format
>= 0)
355 return (__force snd_pcm_format_t
)-EINVAL
;
358 case SNDRV_PCM_FORMAT_MU_LAW
:
359 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); ++i
) {
360 snd_pcm_format_t format1
= preferred_formats
[i
];
361 if (snd_mask_test(format_mask
, (__force
int)format1
))
366 return (__force snd_pcm_format_t
)-EINVAL
;
371 int snd_pcm_plug_format_plugins(struct snd_pcm_substream
*plug
,
372 struct snd_pcm_hw_params
*params
,
373 struct snd_pcm_hw_params
*slave_params
)
375 struct snd_pcm_plugin_format tmpformat
;
376 struct snd_pcm_plugin_format dstformat
;
377 struct snd_pcm_plugin_format srcformat
;
378 snd_pcm_access_t src_access
, dst_access
;
379 struct snd_pcm_plugin
*plugin
= NULL
;
381 int stream
= snd_pcm_plug_stream(plug
);
382 int slave_interleaved
= (params_channels(slave_params
) == 1 ||
383 params_access(slave_params
) == SNDRV_PCM_ACCESS_RW_INTERLEAVED
);
386 case SNDRV_PCM_STREAM_PLAYBACK
:
387 dstformat
.format
= params_format(slave_params
);
388 dstformat
.rate
= params_rate(slave_params
);
389 dstformat
.channels
= params_channels(slave_params
);
390 srcformat
.format
= params_format(params
);
391 srcformat
.rate
= params_rate(params
);
392 srcformat
.channels
= params_channels(params
);
393 src_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
394 dst_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
395 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
397 case SNDRV_PCM_STREAM_CAPTURE
:
398 dstformat
.format
= params_format(params
);
399 dstformat
.rate
= params_rate(params
);
400 dstformat
.channels
= params_channels(params
);
401 srcformat
.format
= params_format(slave_params
);
402 srcformat
.rate
= params_rate(slave_params
);
403 srcformat
.channels
= params_channels(slave_params
);
404 src_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
405 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
406 dst_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
412 tmpformat
= srcformat
;
414 pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
418 pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
423 /* Format change (linearization) */
424 if (! rate_match(srcformat
.rate
, dstformat
.rate
) &&
425 ! snd_pcm_format_linear(srcformat
.format
)) {
426 if (srcformat
.format
!= SNDRV_PCM_FORMAT_MU_LAW
)
428 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
429 err
= snd_pcm_plugin_build_mulaw(plug
,
430 &srcformat
, &tmpformat
,
434 err
= snd_pcm_plugin_append(plugin
);
436 snd_pcm_plugin_free(plugin
);
439 srcformat
= tmpformat
;
440 src_access
= dst_access
;
443 /* channels reduction */
444 if (srcformat
.channels
> dstformat
.channels
) {
445 tmpformat
.channels
= dstformat
.channels
;
446 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
447 pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
450 err
= snd_pcm_plugin_append(plugin
);
452 snd_pcm_plugin_free(plugin
);
455 srcformat
= tmpformat
;
456 src_access
= dst_access
;
459 /* rate resampling */
460 if (!rate_match(srcformat
.rate
, dstformat
.rate
)) {
461 if (srcformat
.format
!= SNDRV_PCM_FORMAT_S16
) {
462 /* convert to S16 for resampling */
463 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
464 err
= snd_pcm_plugin_build_linear(plug
,
465 &srcformat
, &tmpformat
,
469 err
= snd_pcm_plugin_append(plugin
);
471 snd_pcm_plugin_free(plugin
);
474 srcformat
= tmpformat
;
475 src_access
= dst_access
;
477 tmpformat
.rate
= dstformat
.rate
;
478 err
= snd_pcm_plugin_build_rate(plug
,
479 &srcformat
, &tmpformat
,
481 pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat
.rate
, tmpformat
.rate
, err
);
484 err
= snd_pcm_plugin_append(plugin
);
486 snd_pcm_plugin_free(plugin
);
489 srcformat
= tmpformat
;
490 src_access
= dst_access
;
494 if (srcformat
.format
!= dstformat
.format
) {
495 tmpformat
.format
= dstformat
.format
;
496 if (srcformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
||
497 tmpformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
) {
498 err
= snd_pcm_plugin_build_mulaw(plug
,
499 &srcformat
, &tmpformat
,
502 else if (snd_pcm_format_linear(srcformat
.format
) &&
503 snd_pcm_format_linear(tmpformat
.format
)) {
504 err
= snd_pcm_plugin_build_linear(plug
,
505 &srcformat
, &tmpformat
,
510 pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat
.format
, tmpformat
.format
, err
);
513 err
= snd_pcm_plugin_append(plugin
);
515 snd_pcm_plugin_free(plugin
);
518 srcformat
= tmpformat
;
519 src_access
= dst_access
;
522 /* channels extension */
523 if (srcformat
.channels
< dstformat
.channels
) {
524 tmpformat
.channels
= dstformat
.channels
;
525 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
526 pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
529 err
= snd_pcm_plugin_append(plugin
);
531 snd_pcm_plugin_free(plugin
);
534 srcformat
= tmpformat
;
535 src_access
= dst_access
;
539 if (src_access
!= dst_access
) {
540 err
= snd_pcm_plugin_build_copy(plug
,
544 pdprintf("interleave change (copy: returns %i)\n", err
);
547 err
= snd_pcm_plugin_append(plugin
);
549 snd_pcm_plugin_free(plugin
);
557 snd_pcm_sframes_t
snd_pcm_plug_client_channels_buf(struct snd_pcm_substream
*plug
,
559 snd_pcm_uframes_t count
,
560 struct snd_pcm_plugin_channel
**channels
)
562 struct snd_pcm_plugin
*plugin
;
563 struct snd_pcm_plugin_channel
*v
;
564 struct snd_pcm_plugin_format
*format
;
565 int width
, nchannels
, channel
;
566 int stream
= snd_pcm_plug_stream(plug
);
568 if (snd_BUG_ON(!buf
))
570 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
571 plugin
= snd_pcm_plug_first(plug
);
572 format
= &plugin
->src_format
;
574 plugin
= snd_pcm_plug_last(plug
);
575 format
= &plugin
->dst_format
;
577 v
= plugin
->buf_channels
;
579 width
= snd_pcm_format_physical_width(format
->format
);
582 nchannels
= format
->channels
;
583 if (snd_BUG_ON(plugin
->access
!= SNDRV_PCM_ACCESS_RW_INTERLEAVED
&&
584 format
->channels
> 1))
586 for (channel
= 0; channel
< nchannels
; channel
++, v
++) {
589 v
->wanted
= (stream
== SNDRV_PCM_STREAM_CAPTURE
);
591 v
->area
.first
= channel
* width
;
592 v
->area
.step
= nchannels
* width
;
597 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
)
599 struct snd_pcm_plugin
*plugin
, *next
;
600 struct snd_pcm_plugin_channel
*dst_channels
;
602 snd_pcm_sframes_t frames
= size
;
604 plugin
= snd_pcm_plug_first(plug
);
610 snd_pcm_sframes_t frames1
= frames
;
611 if (plugin
->dst_frames
) {
612 frames1
= plugin
->dst_frames(plugin
, frames
);
616 err
= next
->client_channels(next
, frames1
, &dst_channels
);
619 if (err
!= frames1
) {
621 if (plugin
->src_frames
) {
622 frames
= plugin
->src_frames(plugin
, frames1
);
629 pdprintf("write plugin: %s, %li\n", plugin
->name
, frames
);
630 frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
);
633 src_channels
= dst_channels
;
636 return calc_src_frames(plug
, frames
, true);
639 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
)
641 struct snd_pcm_plugin
*plugin
, *next
;
642 struct snd_pcm_plugin_channel
*src_channels
, *dst_channels
;
643 snd_pcm_sframes_t frames
= size
;
646 frames
= calc_src_frames(plug
, frames
, true);
651 plugin
= snd_pcm_plug_first(plug
);
652 while (plugin
&& frames
> 0) {
655 err
= plugin
->client_channels(plugin
, frames
, &dst_channels
);
660 dst_channels
= dst_channels_final
;
662 pdprintf("read plugin: %s, %li\n", plugin
->name
, frames
);
663 frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
);
667 src_channels
= dst_channels
;
672 int snd_pcm_area_silence(const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
673 size_t samples
, snd_pcm_format_t format
)
675 /* FIXME: sub byte resolution and odd dst_offset */
677 unsigned int dst_step
;
679 const unsigned char *silence
;
682 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
683 width
= snd_pcm_format_physical_width(format
);
686 if (dst_area
->step
== (unsigned int) width
&& width
>= 8)
687 return snd_pcm_format_set_silence(format
, dst
, samples
);
688 silence
= snd_pcm_format_silence_64(format
);
691 dst_step
= dst_area
->step
/ 8;
694 int dstbit
= dst_area
->first
% 8;
695 int dstbit_step
= dst_area
->step
% 8;
696 while (samples
-- > 0) {
702 dstbit
+= dstbit_step
;
710 while (samples
-- > 0) {
711 memcpy(dst
, silence
, width
);
718 int snd_pcm_area_copy(const struct snd_pcm_channel_area
*src_area
, size_t src_offset
,
719 const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
720 size_t samples
, snd_pcm_format_t format
)
722 /* FIXME: sub byte resolution and odd dst_offset */
725 int src_step
, dst_step
;
726 src
= src_area
->addr
+ (src_area
->first
+ src_area
->step
* src_offset
) / 8;
728 return snd_pcm_area_silence(dst_area
, dst_offset
, samples
, format
);
729 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
732 width
= snd_pcm_format_physical_width(format
);
735 if (src_area
->step
== (unsigned int) width
&&
736 dst_area
->step
== (unsigned int) width
&& width
>= 8) {
737 size_t bytes
= samples
* width
/ 8;
738 memcpy(dst
, src
, bytes
);
741 src_step
= src_area
->step
/ 8;
742 dst_step
= dst_area
->step
/ 8;
745 int srcbit
= src_area
->first
% 8;
746 int srcbit_step
= src_area
->step
% 8;
747 int dstbit
= dst_area
->first
% 8;
748 int dstbit_step
= dst_area
->step
% 8;
749 while (samples
-- > 0) {
750 unsigned char srcval
;
752 srcval
= *src
& 0x0f;
754 srcval
= (*src
& 0xf0) >> 4;
756 *dst
= (*dst
& 0xf0) | srcval
;
758 *dst
= (*dst
& 0x0f) | (srcval
<< 4);
760 srcbit
+= srcbit_step
;
766 dstbit
+= dstbit_step
;
774 while (samples
-- > 0) {
775 memcpy(dst
, src
, width
);