linux-stable/sound/core/oss/pcm_plugin.c
Clemens Ladisch fea952e5cc ALSA: core: sparse cleanups
Change the core code where sparse complains.  In most cases, this means
just adding annotations to confirm that we indeed want to do the dirty
things we're doing.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2011-02-14 17:10:11 +01:00

756 lines
21 KiB
C

/*
* PCM Plug-In shared (kernel/library) code
* Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
* Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
*
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#if 0
#define PLUGIN_DEBUG
#endif
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include "pcm_plugin.h"
#define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
#define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
/*
* because some cards might have rates "very close", we ignore
* all "resampling" requests within +-5%
*/
static int rate_match(unsigned int src_rate, unsigned int dst_rate)
{
unsigned int low = (src_rate * 95) / 100;
unsigned int high = (src_rate * 105) / 100;
return dst_rate >= low && dst_rate <= high;
}
static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
{
struct snd_pcm_plugin_format *format;
ssize_t width;
size_t size;
unsigned int channel;
struct snd_pcm_plugin_channel *c;
if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
format = &plugin->src_format;
} else {
format = &plugin->dst_format;
}
if ((width = snd_pcm_format_physical_width(format->format)) < 0)
return width;
size = frames * format->channels * width;
if (snd_BUG_ON(size % 8))
return -ENXIO;
size /= 8;
if (plugin->buf_frames < frames) {
vfree(plugin->buf);
plugin->buf = vmalloc(size);
plugin->buf_frames = frames;
}
if (!plugin->buf) {
plugin->buf_frames = 0;
return -ENOMEM;
}
c = plugin->buf_channels;
if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
for (channel = 0; channel < format->channels; channel++, c++) {
c->frames = frames;
c->enabled = 1;
c->wanted = 0;
c->area.addr = plugin->buf;
c->area.first = channel * width;
c->area.step = format->channels * width;
}
} else if (plugin->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED) {
if (snd_BUG_ON(size % format->channels))
return -EINVAL;
size /= format->channels;
for (channel = 0; channel < format->channels; channel++, c++) {
c->frames = frames;
c->enabled = 1;
c->wanted = 0;
c->area.addr = plugin->buf + (channel * size);
c->area.first = 0;
c->area.step = width;
}
} else
return -EINVAL;
return 0;
}
int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
{
int err;
if (snd_BUG_ON(!snd_pcm_plug_first(plug)))
return -ENXIO;
if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
while (plugin->next) {
if (plugin->dst_frames)
frames = plugin->dst_frames(plugin, frames);
if (snd_BUG_ON(frames <= 0))
return -ENXIO;
plugin = plugin->next;
err = snd_pcm_plugin_alloc(plugin, frames);
if (err < 0)
return err;
}
} else {
struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
while (plugin->prev) {
if (plugin->src_frames)
frames = plugin->src_frames(plugin, frames);
if (snd_BUG_ON(frames <= 0))
return -ENXIO;
plugin = plugin->prev;
err = snd_pcm_plugin_alloc(plugin, frames);
if (err < 0)
return err;
}
}
return 0;
}
snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
snd_pcm_uframes_t frames,
struct snd_pcm_plugin_channel **channels)
{
*channels = plugin->buf_channels;
return frames;
}
int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
const char *name,
struct snd_pcm_plugin_format *src_format,
struct snd_pcm_plugin_format *dst_format,
size_t extra,
struct snd_pcm_plugin **ret)
{
struct snd_pcm_plugin *plugin;
unsigned int channels;
if (snd_BUG_ON(!plug))
return -ENXIO;
if (snd_BUG_ON(!src_format || !dst_format))
return -ENXIO;
plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
if (plugin == NULL)
return -ENOMEM;
plugin->name = name;
plugin->plug = plug;
plugin->stream = snd_pcm_plug_stream(plug);
plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
plugin->src_format = *src_format;
plugin->src_width = snd_pcm_format_physical_width(src_format->format);
snd_BUG_ON(plugin->src_width <= 0);
plugin->dst_format = *dst_format;
plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
snd_BUG_ON(plugin->dst_width <= 0);
if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
channels = src_format->channels;
else
channels = dst_format->channels;
plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
if (plugin->buf_channels == NULL) {
snd_pcm_plugin_free(plugin);
return -ENOMEM;
}
plugin->client_channels = snd_pcm_plugin_client_channels;
*ret = plugin;
return 0;
}
int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
{
if (! plugin)
return 0;
if (plugin->private_free)
plugin->private_free(plugin);
kfree(plugin->buf_channels);
vfree(plugin->buf);
kfree(plugin);
return 0;
}
snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
{
struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
int stream = snd_pcm_plug_stream(plug);
if (snd_BUG_ON(!plug))
return -ENXIO;
if (drv_frames == 0)
return 0;
if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
plugin = snd_pcm_plug_last(plug);
while (plugin && drv_frames > 0) {
plugin_prev = plugin->prev;
if (plugin->src_frames)
drv_frames = plugin->src_frames(plugin, drv_frames);
plugin = plugin_prev;
}
} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
plugin = snd_pcm_plug_first(plug);
while (plugin && drv_frames > 0) {
plugin_next = plugin->next;
if (plugin->dst_frames)
drv_frames = plugin->dst_frames(plugin, drv_frames);
plugin = plugin_next;
}
} else
snd_BUG();
return drv_frames;
}
snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
{
struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
snd_pcm_sframes_t frames;
int stream = snd_pcm_plug_stream(plug);
if (snd_BUG_ON(!plug))
return -ENXIO;
if (clt_frames == 0)
return 0;
frames = clt_frames;
if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
plugin = snd_pcm_plug_first(plug);
while (plugin && frames > 0) {
plugin_next = plugin->next;
if (plugin->dst_frames) {
frames = plugin->dst_frames(plugin, frames);
if (frames < 0)
return frames;
}
plugin = plugin_next;
}
} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
plugin = snd_pcm_plug_last(plug);
while (plugin) {
plugin_prev = plugin->prev;
if (plugin->src_frames) {
frames = plugin->src_frames(plugin, frames);
if (frames < 0)
return frames;
}
plugin = plugin_prev;
}
} else
snd_BUG();
return frames;
}
static int snd_pcm_plug_formats(struct snd_mask *mask, snd_pcm_format_t format)
{
struct snd_mask formats = *mask;
u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
SNDRV_PCM_FMTBIT_U24_3LE | SNDRV_PCM_FMTBIT_S24_3LE |
SNDRV_PCM_FMTBIT_U24_3BE | SNDRV_PCM_FMTBIT_S24_3BE |
SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
snd_mask_set(&formats, (__force int)SNDRV_PCM_FORMAT_MU_LAW);
if (formats.bits[0] & (u32)linfmts)
formats.bits[0] |= (u32)linfmts;
if (formats.bits[1] & (u32)(linfmts >> 32))
formats.bits[1] |= (u32)(linfmts >> 32);
return snd_mask_test(&formats, (__force int)format);
}
static snd_pcm_format_t preferred_formats[] = {
SNDRV_PCM_FORMAT_S16_LE,
SNDRV_PCM_FORMAT_S16_BE,
SNDRV_PCM_FORMAT_U16_LE,
SNDRV_PCM_FORMAT_U16_BE,
SNDRV_PCM_FORMAT_S24_3LE,
SNDRV_PCM_FORMAT_S24_3BE,
SNDRV_PCM_FORMAT_U24_3LE,
SNDRV_PCM_FORMAT_U24_3BE,
SNDRV_PCM_FORMAT_S24_LE,
SNDRV_PCM_FORMAT_S24_BE,
SNDRV_PCM_FORMAT_U24_LE,
SNDRV_PCM_FORMAT_U24_BE,
SNDRV_PCM_FORMAT_S32_LE,
SNDRV_PCM_FORMAT_S32_BE,
SNDRV_PCM_FORMAT_U32_LE,
SNDRV_PCM_FORMAT_U32_BE,
SNDRV_PCM_FORMAT_S8,
SNDRV_PCM_FORMAT_U8
};
snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format,
struct snd_mask *format_mask)
{
int i;
if (snd_mask_test(format_mask, (__force int)format))
return format;
if (!snd_pcm_plug_formats(format_mask, format))
return (__force snd_pcm_format_t)-EINVAL;
if (snd_pcm_format_linear(format)) {
unsigned int width = snd_pcm_format_width(format);
int unsignd = snd_pcm_format_unsigned(format) > 0;
int big = snd_pcm_format_big_endian(format) > 0;
unsigned int badness, best = -1;
snd_pcm_format_t best_format = (__force snd_pcm_format_t)-1;
for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
snd_pcm_format_t f = preferred_formats[i];
unsigned int w;
if (!snd_mask_test(format_mask, (__force int)f))
continue;
w = snd_pcm_format_width(f);
if (w >= width)
badness = w - width;
else
badness = width - w + 32;
badness += snd_pcm_format_unsigned(f) != unsignd;
badness += snd_pcm_format_big_endian(f) != big;
if (badness < best) {
best_format = f;
best = badness;
}
}
if ((__force int)best_format >= 0)
return best_format;
else
return (__force snd_pcm_format_t)-EINVAL;
} else {
switch (format) {
case SNDRV_PCM_FORMAT_MU_LAW:
for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
snd_pcm_format_t format1 = preferred_formats[i];
if (snd_mask_test(format_mask, (__force int)format1))
return format1;
}
default:
return (__force snd_pcm_format_t)-EINVAL;
}
}
}
int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
struct snd_pcm_hw_params *params,
struct snd_pcm_hw_params *slave_params)
{
struct snd_pcm_plugin_format tmpformat;
struct snd_pcm_plugin_format dstformat;
struct snd_pcm_plugin_format srcformat;
snd_pcm_access_t src_access, dst_access;
struct snd_pcm_plugin *plugin = NULL;
int err;
int stream = snd_pcm_plug_stream(plug);
int slave_interleaved = (params_channels(slave_params) == 1 ||
params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
switch (stream) {
case SNDRV_PCM_STREAM_PLAYBACK:
dstformat.format = params_format(slave_params);
dstformat.rate = params_rate(slave_params);
dstformat.channels = params_channels(slave_params);
srcformat.format = params_format(params);
srcformat.rate = params_rate(params);
srcformat.channels = params_channels(params);
src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
break;
case SNDRV_PCM_STREAM_CAPTURE:
dstformat.format = params_format(params);
dstformat.rate = params_rate(params);
dstformat.channels = params_channels(params);
srcformat.format = params_format(slave_params);
srcformat.rate = params_rate(slave_params);
srcformat.channels = params_channels(slave_params);
src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
break;
default:
snd_BUG();
return -EINVAL;
}
tmpformat = srcformat;
pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
srcformat.format,
srcformat.rate,
srcformat.channels);
pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
dstformat.format,
dstformat.rate,
dstformat.channels);
/* Format change (linearization) */
if (! rate_match(srcformat.rate, dstformat.rate) &&
! snd_pcm_format_linear(srcformat.format)) {
if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
return -EINVAL;
tmpformat.format = SNDRV_PCM_FORMAT_S16;
err = snd_pcm_plugin_build_mulaw(plug,
&srcformat, &tmpformat,
&plugin);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
/* channels reduction */
if (srcformat.channels > dstformat.channels) {
tmpformat.channels = dstformat.channels;
err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
/* rate resampling */
if (!rate_match(srcformat.rate, dstformat.rate)) {
if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
/* convert to S16 for resampling */
tmpformat.format = SNDRV_PCM_FORMAT_S16;
err = snd_pcm_plugin_build_linear(plug,
&srcformat, &tmpformat,
&plugin);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
tmpformat.rate = dstformat.rate;
err = snd_pcm_plugin_build_rate(plug,
&srcformat, &tmpformat,
&plugin);
pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
/* format change */
if (srcformat.format != dstformat.format) {
tmpformat.format = dstformat.format;
if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
err = snd_pcm_plugin_build_mulaw(plug,
&srcformat, &tmpformat,
&plugin);
}
else if (snd_pcm_format_linear(srcformat.format) &&
snd_pcm_format_linear(tmpformat.format)) {
err = snd_pcm_plugin_build_linear(plug,
&srcformat, &tmpformat,
&plugin);
}
else
return -EINVAL;
pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
/* channels extension */
if (srcformat.channels < dstformat.channels) {
tmpformat.channels = dstformat.channels;
err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
srcformat = tmpformat;
src_access = dst_access;
}
/* de-interleave */
if (src_access != dst_access) {
err = snd_pcm_plugin_build_copy(plug,
&srcformat,
&tmpformat,
&plugin);
pdprintf("interleave change (copy: returns %i)\n", err);
if (err < 0)
return err;
err = snd_pcm_plugin_append(plugin);
if (err < 0) {
snd_pcm_plugin_free(plugin);
return err;
}
}
return 0;
}
snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
char *buf,
snd_pcm_uframes_t count,
struct snd_pcm_plugin_channel **channels)
{
struct snd_pcm_plugin *plugin;
struct snd_pcm_plugin_channel *v;
struct snd_pcm_plugin_format *format;
int width, nchannels, channel;
int stream = snd_pcm_plug_stream(plug);
if (snd_BUG_ON(!buf))
return -ENXIO;
if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
plugin = snd_pcm_plug_first(plug);
format = &plugin->src_format;
} else {
plugin = snd_pcm_plug_last(plug);
format = &plugin->dst_format;
}
v = plugin->buf_channels;
*channels = v;
if ((width = snd_pcm_format_physical_width(format->format)) < 0)
return width;
nchannels = format->channels;
if (snd_BUG_ON(plugin->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
format->channels > 1))
return -ENXIO;
for (channel = 0; channel < nchannels; channel++, v++) {
v->frames = count;
v->enabled = 1;
v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
v->area.addr = buf;
v->area.first = channel * width;
v->area.step = nchannels * width;
}
return count;
}
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)
{
struct snd_pcm_plugin *plugin, *next;
struct snd_pcm_plugin_channel *dst_channels;
int err;
snd_pcm_sframes_t frames = size;
plugin = snd_pcm_plug_first(plug);
while (plugin && frames > 0) {
if ((next = plugin->next) != NULL) {
snd_pcm_sframes_t frames1 = frames;
if (plugin->dst_frames)
frames1 = plugin->dst_frames(plugin, frames);
if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
return err;
}
if (err != frames1) {
frames = err;
if (plugin->src_frames)
frames = plugin->src_frames(plugin, frames1);
}
} else
dst_channels = NULL;
pdprintf("write plugin: %s, %li\n", plugin->name, frames);
if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
return frames;
src_channels = dst_channels;
plugin = next;
}
return snd_pcm_plug_client_size(plug, frames);
}
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)
{
struct snd_pcm_plugin *plugin, *next;
struct snd_pcm_plugin_channel *src_channels, *dst_channels;
snd_pcm_sframes_t frames = size;
int err;
frames = snd_pcm_plug_slave_size(plug, frames);
if (frames < 0)
return frames;
src_channels = NULL;
plugin = snd_pcm_plug_first(plug);
while (plugin && frames > 0) {
if ((next = plugin->next) != NULL) {
if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
return err;
}
frames = err;
} else {
dst_channels = dst_channels_final;
}
pdprintf("read plugin: %s, %li\n", plugin->name, frames);
if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
return frames;
plugin = next;
src_channels = dst_channels;
}
return frames;
}
int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
size_t samples, snd_pcm_format_t format)
{
/* FIXME: sub byte resolution and odd dst_offset */
unsigned char *dst;
unsigned int dst_step;
int width;
const unsigned char *silence;
if (!dst_area->addr)
return 0;
dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
width = snd_pcm_format_physical_width(format);
if (width <= 0)
return -EINVAL;
if (dst_area->step == (unsigned int) width && width >= 8)
return snd_pcm_format_set_silence(format, dst, samples);
silence = snd_pcm_format_silence_64(format);
if (! silence)
return -EINVAL;
dst_step = dst_area->step / 8;
if (width == 4) {
/* Ima ADPCM */
int dstbit = dst_area->first % 8;
int dstbit_step = dst_area->step % 8;
while (samples-- > 0) {
if (dstbit)
*dst &= 0xf0;
else
*dst &= 0x0f;
dst += dst_step;
dstbit += dstbit_step;
if (dstbit == 8) {
dst++;
dstbit = 0;
}
}
} else {
width /= 8;
while (samples-- > 0) {
memcpy(dst, silence, width);
dst += dst_step;
}
}
return 0;
}
int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
size_t samples, snd_pcm_format_t format)
{
/* FIXME: sub byte resolution and odd dst_offset */
char *src, *dst;
int width;
int src_step, dst_step;
src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
if (!src_area->addr)
return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
if (!dst_area->addr)
return 0;
width = snd_pcm_format_physical_width(format);
if (width <= 0)
return -EINVAL;
if (src_area->step == (unsigned int) width &&
dst_area->step == (unsigned int) width && width >= 8) {
size_t bytes = samples * width / 8;
memcpy(dst, src, bytes);
return 0;
}
src_step = src_area->step / 8;
dst_step = dst_area->step / 8;
if (width == 4) {
/* Ima ADPCM */
int srcbit = src_area->first % 8;
int srcbit_step = src_area->step % 8;
int dstbit = dst_area->first % 8;
int dstbit_step = dst_area->step % 8;
while (samples-- > 0) {
unsigned char srcval;
if (srcbit)
srcval = *src & 0x0f;
else
srcval = (*src & 0xf0) >> 4;
if (dstbit)
*dst = (*dst & 0xf0) | srcval;
else
*dst = (*dst & 0x0f) | (srcval << 4);
src += src_step;
srcbit += srcbit_step;
if (srcbit == 8) {
src++;
srcbit = 0;
}
dst += dst_step;
dstbit += dstbit_step;
if (dstbit == 8) {
dst++;
dstbit = 0;
}
}
} else {
width /= 8;
while (samples-- > 0) {
memcpy(dst, src, width);
src += src_step;
dst += dst_step;
}
}
return 0;
}