decoder/opus: move code to class OggVisitor

src/lib/xiph/OggVisitor.cxx

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2003-2016 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 "OggVisitor.hxx"
+
+#include <stdexcept>
+
+void
+OggVisitor::EndStream()
+{
+	if (!has_stream)
+		return;
+
+	has_stream = false;
+	OnOggEnd();
+}
+
+inline bool
+OggVisitor::ReadNextPage()
+{
+	ogg_page page;
+	if (!sync.ExpectPage(page))
+		return false;
+
+	const auto page_serialno = ogg_page_serialno(&page);
+	if (page_serialno != stream.GetSerialNo()) {
+		EndStream();
+		stream.Reinitialize(page_serialno);
+	}
+
+	stream.PageIn(page);
+	return true;
+}
+
+inline void
+OggVisitor::HandlePacket(const ogg_packet &packet)
+{
+	if (packet.b_o_s) {
+		EndStream();
+		has_stream = true;
+		OnOggBeginning(packet);
+		return;
+	}
+
+	if (!has_stream)
+		/* fail if BOS is missing */
+		throw std::runtime_error("BOS packet expected");
+
+	if (packet.e_o_s) {
+		EndStream();
+		return;
+	}
+
+	OnOggPacket(packet);
+}
+
+inline void
+OggVisitor::HandlePackets()
+{
+	ogg_packet packet;
+	while (stream.PacketOut(packet) == 1)
+		HandlePacket(packet);
+}
+
+void
+OggVisitor::Visit()
+{
+	do {
+		HandlePackets();
+	} while (ReadNextPage());
+}
+
+void
+OggVisitor::PostSeek()
+{
+	sync.Reset();
+
+	/* reset the stream to clear any previous partial packet
+	   data */
+	stream.Reset();
+
+	/* find the next Ogg page and feed it into the stream */
+	sync.ExpectPageSeekIn(stream);
+}

src/lib/xiph/OggVisitor.hxx

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2003-2016 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_OGG_VISITOR_HXX
+#define MPD_OGG_VISITOR_HXX
+
+#include "check.h"
+#include "OggSyncState.hxx"
+#include "OggStreamState.hxx"
+
+#include <ogg/ogg.h>
+
+#include <stddef.h>
+
+class Reader;
+
+/**
+ * Abstract class which iterates over Ogg packets in a #Reader.
+ * Subclass it and implement the virtual methods.
+ */
+class OggVisitor {
+	OggSyncState sync;
+	OggStreamState stream;
+
+	bool has_stream = false;
+
+public:
+	explicit OggVisitor(Reader &reader)
+		:sync(reader), stream(0) {}
+
+	long GetSerialNo() const {
+		return stream.GetSerialNo();
+	}
+
+	void Visit();
+
+	/**
+	 * Call this method after seeking the #Reader.
+	 */
+	void PostSeek();
+
+private:
+	void EndStream();
+	bool ReadNextPage();
+	void HandlePacket(const ogg_packet &packet);
+	void HandlePackets();
+
+protected:
+	virtual void OnOggBeginning(const ogg_packet &packet) = 0;
+	virtual void OnOggPacket(const ogg_packet &packet) = 0;
+	virtual void OnOggEnd() = 0;
+};
+
+#endif