111 lines
2.7 KiB
C++
111 lines
2.7 KiB
C++
/*
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* Copyright 2003-2020 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef MPD_OGG_VISITOR_HXX
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#define MPD_OGG_VISITOR_HXX
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#include "OggSyncState.hxx"
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#include "OggStreamState.hxx"
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#include <ogg/ogg.h>
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class Reader;
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/**
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* Abstract class which iterates over Ogg packets in a #Reader.
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* Subclass it and implement the virtual methods.
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*/
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class OggVisitor {
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OggSyncState sync;
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OggStreamState stream;
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bool has_stream = false;
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/**
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* This is true after seeking; its one-time effect is to
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* ignore the BOS packet, just in case we have been seeking to
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* the beginning of the file, because that would disrupt
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* playback.
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*/
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bool post_seek = false;
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public:
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explicit OggVisitor(Reader &reader)
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:sync(reader), stream(0) {}
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long GetSerialNo() const {
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return stream.GetSerialNo();
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}
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uint64_t GetStartOffset() const noexcept {
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return sync.GetStartOffset();
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}
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void Visit();
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/**
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* Call this method after seeking the #Reader.
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*
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* @param offset the current #Reader offset
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*/
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void PostSeek(uint64_t offset);
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/**
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* Skip packets (#ogg_packet) from the #OggStreamState until a
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* packet with a valid granulepos is found or until the stream
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* has run dry.
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*
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* Since this will discard pending packets and will disturb
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* this object, this should only be used while seeking.
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*
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* This method must not be called from within one of the
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* virtual methods.
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*
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* @return the granulepos or -1 if no valid granulepos was
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* found
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*/
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ogg_int64_t ReadGranulepos() noexcept;
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private:
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void EndStream();
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bool ReadNextPage();
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void HandlePacket(const ogg_packet &packet);
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void HandlePackets();
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protected:
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/**
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* Called when the "beginning of stream" packet has been seen.
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*
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* @param packet the "beginning of stream" packet
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*/
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virtual void OnOggBeginning(const ogg_packet &packet) = 0;
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/**
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* Called for each follow-up packet.
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*/
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virtual void OnOggPacket(const ogg_packet &packet) = 0;
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/**
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* Called after the "end of stream" packet has been processed.
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*/
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virtual void OnOggEnd() = 0;
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};
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#endif
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