/* * Copyright 2003-2019 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. */ #ifndef MPD_FILTER_HXX #define MPD_FILTER_HXX #include "AudioFormat.hxx" #include template struct ConstBuffer; 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 {} /** * 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 ConstBuffer FilterPCM(ConstBuffer src) = 0; /** * Flush pending data and return it. This should be called * repeatedly until it returns nullptr. * * Throws on error. */ virtual ConstBuffer Flush(); }; #endif