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backends/mixer/sdl/sdl-mixer.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef BACKENDS_MIXER_SDL_H
+#define BACKENDS_MIXER_SDL_H
+
+#include "backends/platform/sdl/sdl-sys.h"
+#include "backends/mixer/mixer.h"
+
+/**
+ * SDL mixer manager. It wraps the actual implementation
+ * of the Audio:Mixer used by the engine, and setups
+ * the SDL audio subsystem and the callback for the
+ * audio mixer implementation.
+ */
+class SdlMixerManager : public MixerManager {
+public:
+	SdlMixerManager();
+	virtual ~SdlMixerManager();
+
+	/**
+	 * Initialize and setups the mixer
+	 */
+	virtual void init();
+
+	// Used by Event recorder
+
+	/**
+	 * Pauses the audio system
+	 */
+	virtual void suspendAudio();
+
+	/**
+	 * Resumes the audio system
+	 */
+	virtual int resumeAudio();
+
+protected:
+	/**
+	 * The obtained audio specification after opening the
+	 * audio system.
+	 */
+	SDL_AudioSpec _obtained;
+
+	/**
+	 * Returns the desired audio specification
+	 */
+	virtual SDL_AudioSpec getAudioSpec(uint32 rate);
+
+	/**
+	 * Starts SDL audio
+	 */
+	virtual void startAudio();
+
+	/**
+	 * Handles the audio callback
+	 */
+	virtual void callbackHandler(byte *samples, int len);
+
+	/**
+	 * The mixer callback entry point. Static functions can't be overridden
+	 * by subclasses, so it invokes the non-static function callbackHandler()
+	 */
+#if SDL_VERSION_ATLEAST(3, 0, 0)
+	static void sdlCallback(void *userdata, SDL_AudioStream *stream, int additional_amount, int total_amount);
+#else
+	static void sdlCallback(void *this_, byte *samples, int len);
+#endif
+
+	bool _isSubsystemInitialized;
+	bool _isAudioOpen;
+
+#if SDL_VERSION_ATLEAST(3, 0, 0)
+	SDL_AudioStream *_stream = nullptr;
+#endif
+};
+
+#endif