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/*
* Copyright 2003-2017 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "ChainFilterPlugin.hxx"
#include "filter/FilterPlugin.hxx"
#include "filter/FilterInternal.hxx"
#include "filter/FilterRegistry.hxx"
#include "AudioFormat.hxx"
#include "util/ConstBuffer.hxx"
#include "util/StringBuffer.hxx"
#include "util/RuntimeError.hxx"
#include <memory>
#include <list>
#include <assert.h>
class ChainFilter final : public Filter {
struct Child {
const char *name;
Filter *filter;
Child(const char *_name, Filter *_filter)
:name(_name), filter(_filter) {}
~Child() {
delete filter;
}
Child(const Child &) = delete;
Child &operator=(const Child &) = delete;
};
std::list<Child> children;
public:
explicit ChainFilter(AudioFormat _audio_format)
:Filter(_audio_format) {}
void Append(const char *name, Filter *filter) {
assert(out_audio_format.IsValid());
out_audio_format = filter->GetOutAudioFormat();
assert(out_audio_format.IsValid());
children.emplace_back(name, filter);
}
/* virtual methods from class Filter */
void Reset() override;
ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
};
class PreparedChainFilter final : public PreparedFilter {
struct Child {
const char *name;
PreparedFilter *filter;
Child(const char *_name, PreparedFilter *_filter)
:name(_name), filter(_filter) {}
~Child() {
delete filter;
}
Child(const Child &) = delete;
Child &operator=(const Child &) = delete;
Filter *Open(const AudioFormat &prev_audio_format);
};
std::list<Child> children;
public:
void Append(const char *name, PreparedFilter *filter) {
children.emplace_back(name, filter);
}
/* virtual methods from class PreparedFilter */
Filter *Open(AudioFormat &af) override;
};
static PreparedFilter *
chain_filter_init(gcc_unused const ConfigBlock &block)
{
return new PreparedChainFilter();
}
Filter *
PreparedChainFilter::Child::Open(const AudioFormat &prev_audio_format)
{
AudioFormat conv_audio_format = prev_audio_format;
Filter *new_filter = filter->Open(conv_audio_format);
if (conv_audio_format != prev_audio_format) {
delete new_filter;
throw FormatRuntimeError("Audio format not supported by filter '%s': %s",
name,
ToString(prev_audio_format).c_str());
}
return new_filter;
}
Filter *
PreparedChainFilter::Open(AudioFormat &in_audio_format)
{
std::unique_ptr<ChainFilter> chain(new ChainFilter(in_audio_format));
for (auto &child : children) {
AudioFormat audio_format = chain->GetOutAudioFormat();
auto *filter = child.Open(audio_format);
chain->Append(child.name, filter);
}
return chain.release();
}
void
ChainFilter::Reset()
{
for (auto &child : children)
child.filter->Reset();
}
ConstBuffer<void>
ChainFilter::FilterPCM(ConstBuffer<void> src)
{
for (auto &child : children) {
/* feed the output of the previous filter as input
into the current one */
src = child.filter->FilterPCM(src);
}
/* return the output of the last filter */
return src;
}
const FilterPlugin chain_filter_plugin = {
"chain",
chain_filter_init,
};
PreparedFilter *
filter_chain_new(void)
{
return new PreparedChainFilter();
}
void
filter_chain_append(PreparedFilter &_chain, const char *name,
PreparedFilter *filter)
{
PreparedChainFilter &chain = (PreparedChainFilter &)_chain;
chain.Append(name, filter);
}