62 lines
1.2 KiB
C++
62 lines
1.2 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
// Copyright The Music Player Daemon Project
|
|
|
|
#ifndef MPD_FILTER_HXX
|
|
#define MPD_FILTER_HXX
|
|
|
|
#include "pcm/AudioFormat.hxx"
|
|
|
|
#include <cassert>
|
|
#include <cstddef>
|
|
#include <span>
|
|
|
|
class Filter {
|
|
protected:
|
|
AudioFormat out_audio_format;
|
|
|
|
explicit Filter(AudioFormat _out_audio_format) noexcept
|
|
:out_audio_format(_out_audio_format) {
|
|
assert(out_audio_format.IsValid());
|
|
}
|
|
|
|
public:
|
|
virtual ~Filter() noexcept = default;
|
|
|
|
/**
|
|
* Returns the #AudioFormat produced by FilterPCM().
|
|
*/
|
|
const AudioFormat &GetOutAudioFormat() const noexcept {
|
|
return out_audio_format;
|
|
}
|
|
|
|
/**
|
|
* Reset the filter's state, e.g. drop/flush buffers.
|
|
*/
|
|
virtual void Reset() noexcept {
|
|
}
|
|
|
|
/**
|
|
* Filters a block of PCM data.
|
|
*
|
|
* Throws on error.
|
|
*
|
|
* @param src the input buffer
|
|
* @return the destination buffer on success (will be
|
|
* invalidated by deleting this object or the next FilterPCM()
|
|
* or Reset() call)
|
|
*/
|
|
virtual std::span<const std::byte> FilterPCM(std::span<const std::byte> src) = 0;
|
|
|
|
/**
|
|
* Flush pending data and return it. This should be called
|
|
* repeatedly until it returns nullptr.
|
|
*
|
|
* Throws on error.
|
|
*/
|
|
virtual std::span<const std::byte> Flush() {
|
|
return {};
|
|
}
|
|
};
|
|
|
|
#endif
|