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
;
204 if (snd_BUG_ON(!plug
))
208 stream
= snd_pcm_plug_stream(plug
);
209 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
210 plugin
= snd_pcm_plug_last(plug
);
211 while (plugin
&& drv_frames
> 0) {
212 plugin_prev
= plugin
->prev
;
213 if (plugin
->src_frames
)
214 drv_frames
= plugin
->src_frames(plugin
, drv_frames
);
215 plugin
= plugin_prev
;
217 } else if (stream
== SNDRV_PCM_STREAM_CAPTURE
) {
218 plugin
= snd_pcm_plug_first(plug
);
219 while (plugin
&& drv_frames
> 0) {
220 plugin_next
= plugin
->next
;
221 if (plugin
->dst_frames
)
222 drv_frames
= plugin
->dst_frames(plugin
, drv_frames
);
223 plugin
= plugin_next
;
230 snd_pcm_sframes_t
snd_pcm_plug_slave_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t clt_frames
)
232 struct snd_pcm_plugin
*plugin
, *plugin_prev
, *plugin_next
;
233 snd_pcm_sframes_t frames
;
236 if (snd_BUG_ON(!plug
))
241 stream
= snd_pcm_plug_stream(plug
);
242 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
243 plugin
= snd_pcm_plug_first(plug
);
244 while (plugin
&& frames
> 0) {
245 plugin_next
= plugin
->next
;
246 if (plugin
->dst_frames
) {
247 frames
= plugin
->dst_frames(plugin
, frames
);
251 plugin
= plugin_next
;
253 } else if (stream
== SNDRV_PCM_STREAM_CAPTURE
) {
254 plugin
= snd_pcm_plug_last(plug
);
256 plugin_prev
= plugin
->prev
;
257 if (plugin
->src_frames
) {
258 frames
= plugin
->src_frames(plugin
, frames
);
262 plugin
= plugin_prev
;
269 static int snd_pcm_plug_formats(struct snd_mask
*mask
, snd_pcm_format_t format
)
271 struct snd_mask formats
= *mask
;
272 u64 linfmts
= (SNDRV_PCM_FMTBIT_U8
| SNDRV_PCM_FMTBIT_S8
|
273 SNDRV_PCM_FMTBIT_U16_LE
| SNDRV_PCM_FMTBIT_S16_LE
|
274 SNDRV_PCM_FMTBIT_U16_BE
| SNDRV_PCM_FMTBIT_S16_BE
|
275 SNDRV_PCM_FMTBIT_U24_LE
| SNDRV_PCM_FMTBIT_S24_LE
|
276 SNDRV_PCM_FMTBIT_U24_BE
| SNDRV_PCM_FMTBIT_S24_BE
|
277 SNDRV_PCM_FMTBIT_U24_3LE
| SNDRV_PCM_FMTBIT_S24_3LE
|
278 SNDRV_PCM_FMTBIT_U24_3BE
| SNDRV_PCM_FMTBIT_S24_3BE
|
279 SNDRV_PCM_FMTBIT_U32_LE
| SNDRV_PCM_FMTBIT_S32_LE
|
280 SNDRV_PCM_FMTBIT_U32_BE
| SNDRV_PCM_FMTBIT_S32_BE
);
281 snd_mask_set(&formats
, (__force
int)SNDRV_PCM_FORMAT_MU_LAW
);
283 if (formats
.bits
[0] & (u32
)linfmts
)
284 formats
.bits
[0] |= (u32
)linfmts
;
285 if (formats
.bits
[1] & (u32
)(linfmts
>> 32))
286 formats
.bits
[1] |= (u32
)(linfmts
>> 32);
287 return snd_mask_test(&formats
, (__force
int)format
);
290 static snd_pcm_format_t preferred_formats
[] = {
291 SNDRV_PCM_FORMAT_S16_LE
,
292 SNDRV_PCM_FORMAT_S16_BE
,
293 SNDRV_PCM_FORMAT_U16_LE
,
294 SNDRV_PCM_FORMAT_U16_BE
,
295 SNDRV_PCM_FORMAT_S24_3LE
,
296 SNDRV_PCM_FORMAT_S24_3BE
,
297 SNDRV_PCM_FORMAT_U24_3LE
,
298 SNDRV_PCM_FORMAT_U24_3BE
,
299 SNDRV_PCM_FORMAT_S24_LE
,
300 SNDRV_PCM_FORMAT_S24_BE
,
301 SNDRV_PCM_FORMAT_U24_LE
,
302 SNDRV_PCM_FORMAT_U24_BE
,
303 SNDRV_PCM_FORMAT_S32_LE
,
304 SNDRV_PCM_FORMAT_S32_BE
,
305 SNDRV_PCM_FORMAT_U32_LE
,
306 SNDRV_PCM_FORMAT_U32_BE
,
311 snd_pcm_format_t
snd_pcm_plug_slave_format(snd_pcm_format_t format
,
312 struct snd_mask
*format_mask
)
316 if (snd_mask_test(format_mask
, (__force
int)format
))
318 if (!snd_pcm_plug_formats(format_mask
, format
))
319 return (__force snd_pcm_format_t
)-EINVAL
;
320 if (snd_pcm_format_linear(format
)) {
321 unsigned int width
= snd_pcm_format_width(format
);
322 int unsignd
= snd_pcm_format_unsigned(format
) > 0;
323 int big
= snd_pcm_format_big_endian(format
) > 0;
324 unsigned int badness
, best
= -1;
325 snd_pcm_format_t best_format
= (__force snd_pcm_format_t
)-1;
326 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); i
++) {
327 snd_pcm_format_t f
= preferred_formats
[i
];
329 if (!snd_mask_test(format_mask
, (__force
int)f
))
331 w
= snd_pcm_format_width(f
);
335 badness
= width
- w
+ 32;
336 badness
+= snd_pcm_format_unsigned(f
) != unsignd
;
337 badness
+= snd_pcm_format_big_endian(f
) != big
;
338 if (badness
< best
) {
343 if ((__force
int)best_format
>= 0)
346 return (__force snd_pcm_format_t
)-EINVAL
;
349 case SNDRV_PCM_FORMAT_MU_LAW
:
350 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); ++i
) {
351 snd_pcm_format_t format1
= preferred_formats
[i
];
352 if (snd_mask_test(format_mask
, (__force
int)format1
))
356 return (__force snd_pcm_format_t
)-EINVAL
;
361 int snd_pcm_plug_format_plugins(struct snd_pcm_substream
*plug
,
362 struct snd_pcm_hw_params
*params
,
363 struct snd_pcm_hw_params
*slave_params
)
365 struct snd_pcm_plugin_format tmpformat
;
366 struct snd_pcm_plugin_format dstformat
;
367 struct snd_pcm_plugin_format srcformat
;
368 snd_pcm_access_t src_access
, dst_access
;
369 struct snd_pcm_plugin
*plugin
= NULL
;
371 int stream
= snd_pcm_plug_stream(plug
);
372 int slave_interleaved
= (params_channels(slave_params
) == 1 ||
373 params_access(slave_params
) == SNDRV_PCM_ACCESS_RW_INTERLEAVED
);
376 case SNDRV_PCM_STREAM_PLAYBACK
:
377 dstformat
.format
= params_format(slave_params
);
378 dstformat
.rate
= params_rate(slave_params
);
379 dstformat
.channels
= params_channels(slave_params
);
380 srcformat
.format
= params_format(params
);
381 srcformat
.rate
= params_rate(params
);
382 srcformat
.channels
= params_channels(params
);
383 src_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
384 dst_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
385 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
387 case SNDRV_PCM_STREAM_CAPTURE
:
388 dstformat
.format
= params_format(params
);
389 dstformat
.rate
= params_rate(params
);
390 dstformat
.channels
= params_channels(params
);
391 srcformat
.format
= params_format(slave_params
);
392 srcformat
.rate
= params_rate(slave_params
);
393 srcformat
.channels
= params_channels(slave_params
);
394 src_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
395 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
396 dst_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
402 tmpformat
= srcformat
;
404 pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
408 pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
413 /* Format change (linearization) */
414 if (! rate_match(srcformat
.rate
, dstformat
.rate
) &&
415 ! snd_pcm_format_linear(srcformat
.format
)) {
416 if (srcformat
.format
!= SNDRV_PCM_FORMAT_MU_LAW
)
418 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
419 err
= snd_pcm_plugin_build_mulaw(plug
,
420 &srcformat
, &tmpformat
,
424 err
= snd_pcm_plugin_append(plugin
);
426 snd_pcm_plugin_free(plugin
);
429 srcformat
= tmpformat
;
430 src_access
= dst_access
;
433 /* channels reduction */
434 if (srcformat
.channels
> dstformat
.channels
) {
435 tmpformat
.channels
= dstformat
.channels
;
436 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
437 pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
440 err
= snd_pcm_plugin_append(plugin
);
442 snd_pcm_plugin_free(plugin
);
445 srcformat
= tmpformat
;
446 src_access
= dst_access
;
449 /* rate resampling */
450 if (!rate_match(srcformat
.rate
, dstformat
.rate
)) {
451 if (srcformat
.format
!= SNDRV_PCM_FORMAT_S16
) {
452 /* convert to S16 for resampling */
453 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
454 err
= snd_pcm_plugin_build_linear(plug
,
455 &srcformat
, &tmpformat
,
459 err
= snd_pcm_plugin_append(plugin
);
461 snd_pcm_plugin_free(plugin
);
464 srcformat
= tmpformat
;
465 src_access
= dst_access
;
467 tmpformat
.rate
= dstformat
.rate
;
468 err
= snd_pcm_plugin_build_rate(plug
,
469 &srcformat
, &tmpformat
,
471 pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat
.rate
, tmpformat
.rate
, err
);
474 err
= snd_pcm_plugin_append(plugin
);
476 snd_pcm_plugin_free(plugin
);
479 srcformat
= tmpformat
;
480 src_access
= dst_access
;
484 if (srcformat
.format
!= dstformat
.format
) {
485 tmpformat
.format
= dstformat
.format
;
486 if (srcformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
||
487 tmpformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
) {
488 err
= snd_pcm_plugin_build_mulaw(plug
,
489 &srcformat
, &tmpformat
,
492 else if (snd_pcm_format_linear(srcformat
.format
) &&
493 snd_pcm_format_linear(tmpformat
.format
)) {
494 err
= snd_pcm_plugin_build_linear(plug
,
495 &srcformat
, &tmpformat
,
500 pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat
.format
, tmpformat
.format
, err
);
503 err
= snd_pcm_plugin_append(plugin
);
505 snd_pcm_plugin_free(plugin
);
508 srcformat
= tmpformat
;
509 src_access
= dst_access
;
512 /* channels extension */
513 if (srcformat
.channels
< dstformat
.channels
) {
514 tmpformat
.channels
= dstformat
.channels
;
515 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
516 pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
519 err
= snd_pcm_plugin_append(plugin
);
521 snd_pcm_plugin_free(plugin
);
524 srcformat
= tmpformat
;
525 src_access
= dst_access
;
529 if (src_access
!= dst_access
) {
530 err
= snd_pcm_plugin_build_copy(plug
,
534 pdprintf("interleave change (copy: returns %i)\n", err
);
537 err
= snd_pcm_plugin_append(plugin
);
539 snd_pcm_plugin_free(plugin
);
547 snd_pcm_sframes_t
snd_pcm_plug_client_channels_buf(struct snd_pcm_substream
*plug
,
549 snd_pcm_uframes_t count
,
550 struct snd_pcm_plugin_channel
**channels
)
552 struct snd_pcm_plugin
*plugin
;
553 struct snd_pcm_plugin_channel
*v
;
554 struct snd_pcm_plugin_format
*format
;
555 int width
, nchannels
, channel
;
556 int stream
= snd_pcm_plug_stream(plug
);
558 if (snd_BUG_ON(!buf
))
560 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
561 plugin
= snd_pcm_plug_first(plug
);
562 format
= &plugin
->src_format
;
564 plugin
= snd_pcm_plug_last(plug
);
565 format
= &plugin
->dst_format
;
567 v
= plugin
->buf_channels
;
569 if ((width
= snd_pcm_format_physical_width(format
->format
)) < 0)
571 nchannels
= format
->channels
;
572 if (snd_BUG_ON(plugin
->access
!= SNDRV_PCM_ACCESS_RW_INTERLEAVED
&&
573 format
->channels
> 1))
575 for (channel
= 0; channel
< nchannels
; channel
++, v
++) {
578 v
->wanted
= (stream
== SNDRV_PCM_STREAM_CAPTURE
);
580 v
->area
.first
= channel
* width
;
581 v
->area
.step
= nchannels
* width
;
586 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
)
588 struct snd_pcm_plugin
*plugin
, *next
;
589 struct snd_pcm_plugin_channel
*dst_channels
;
591 snd_pcm_sframes_t frames
= size
;
593 plugin
= snd_pcm_plug_first(plug
);
594 while (plugin
&& frames
> 0) {
595 if ((next
= plugin
->next
) != NULL
) {
596 snd_pcm_sframes_t frames1
= frames
;
597 if (plugin
->dst_frames
)
598 frames1
= plugin
->dst_frames(plugin
, frames
);
599 if ((err
= next
->client_channels(next
, frames1
, &dst_channels
)) < 0) {
602 if (err
!= frames1
) {
604 if (plugin
->src_frames
)
605 frames
= plugin
->src_frames(plugin
, frames1
);
609 pdprintf("write plugin: %s, %li\n", plugin
->name
, frames
);
610 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
612 src_channels
= dst_channels
;
615 return snd_pcm_plug_client_size(plug
, frames
);
618 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
)
620 struct snd_pcm_plugin
*plugin
, *next
;
621 struct snd_pcm_plugin_channel
*src_channels
, *dst_channels
;
622 snd_pcm_sframes_t frames
= size
;
625 frames
= snd_pcm_plug_slave_size(plug
, frames
);
630 plugin
= snd_pcm_plug_first(plug
);
631 while (plugin
&& frames
> 0) {
632 if ((next
= plugin
->next
) != NULL
) {
633 if ((err
= plugin
->client_channels(plugin
, frames
, &dst_channels
)) < 0) {
638 dst_channels
= dst_channels_final
;
640 pdprintf("read plugin: %s, %li\n", plugin
->name
, frames
);
641 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
644 src_channels
= dst_channels
;
649 int snd_pcm_area_silence(const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
650 size_t samples
, snd_pcm_format_t format
)
652 /* FIXME: sub byte resolution and odd dst_offset */
654 unsigned int dst_step
;
656 const unsigned char *silence
;
659 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
660 width
= snd_pcm_format_physical_width(format
);
663 if (dst_area
->step
== (unsigned int) width
&& width
>= 8)
664 return snd_pcm_format_set_silence(format
, dst
, samples
);
665 silence
= snd_pcm_format_silence_64(format
);
668 dst_step
= dst_area
->step
/ 8;
671 int dstbit
= dst_area
->first
% 8;
672 int dstbit_step
= dst_area
->step
% 8;
673 while (samples
-- > 0) {
679 dstbit
+= dstbit_step
;
687 while (samples
-- > 0) {
688 memcpy(dst
, silence
, width
);
695 int snd_pcm_area_copy(const struct snd_pcm_channel_area
*src_area
, size_t src_offset
,
696 const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
697 size_t samples
, snd_pcm_format_t format
)
699 /* FIXME: sub byte resolution and odd dst_offset */
702 int src_step
, dst_step
;
703 src
= src_area
->addr
+ (src_area
->first
+ src_area
->step
* src_offset
) / 8;
705 return snd_pcm_area_silence(dst_area
, dst_offset
, samples
, format
);
706 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
709 width
= snd_pcm_format_physical_width(format
);
712 if (src_area
->step
== (unsigned int) width
&&
713 dst_area
->step
== (unsigned int) width
&& width
>= 8) {
714 size_t bytes
= samples
* width
/ 8;
715 memcpy(dst
, src
, bytes
);
718 src_step
= src_area
->step
/ 8;
719 dst_step
= dst_area
->step
/ 8;
722 int srcbit
= src_area
->first
% 8;
723 int srcbit_step
= src_area
->step
% 8;
724 int dstbit
= dst_area
->first
% 8;
725 int dstbit_step
= dst_area
->step
% 8;
726 while (samples
-- > 0) {
727 unsigned char srcval
;
729 srcval
= *src
& 0x0f;
731 srcval
= (*src
& 0xf0) >> 4;
733 *dst
= (*dst
& 0xf0) | srcval
;
735 *dst
= (*dst
& 0x0f) | (srcval
<< 4);
737 srcbit
+= srcbit_step
;
743 dstbit
+= dstbit_step
;
751 while (samples
-- > 0) {
752 memcpy(dst
, src
, width
);