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linux/sound/core/oss/pcm_plugin.c

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/*
* 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 <sound/driver.h>
#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;
snd_assert((size % 8) == 0, 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) {
snd_assert((size % format->channels) == 0,);
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;
snd_assert(snd_pcm_plug_first(plug) != NULL, 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);
snd_assert(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);
snd_assert(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;
snd_assert(plug != NULL, return -ENXIO);
snd_assert(src_format != NULL && dst_format != NULL, 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_assert(plugin->src_width > 0, );
plugin->dst_format = *dst_format;
plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
snd_assert(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);
snd_assert(plug != NULL, 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);
snd_assert(plug != NULL, 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, int 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, 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, format);
}
static int 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
};
int snd_pcm_plug_slave_format(int format, struct snd_mask *format_mask)
{
int i;
if (snd_mask_test(format_mask, format))
return format;
if (! snd_pcm_plug_formats(format_mask, format))
return -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;
int best_format = -1;
for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
int f = preferred_formats[i];
unsigned int w;
if (!snd_mask_test(format_mask, 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;
}
}
return best_format >= 0 ? best_format : -EINVAL;
} else {
switch (format) {
case SNDRV_PCM_FORMAT_MU_LAW:
for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
int format1 = preferred_formats[i];
if (snd_mask_test(format_mask, format1))
return format1;
}
default:
return -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;
int 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);
snd_assert(buf != NULL, 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;
snd_assert(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, int 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, int 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;
}
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