Linux: Alsa backend for the audio plugins. Didn't succeed in reducing latency though, but hopefully will work better than libao - shouldn't hang weirdly at underruns, I hope, like libao does.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@4240 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Core/AudioCommon/Src/AlsaSoundStream.h

@@ -0,0 +1,69 @@
+// Copyright (C) 2003 Dolphin Project.
+
+// 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, version 2.0.
+
+// 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 2.0 for more details.
+
+// A copy of the GPL 2.0 should have been included with the program.
+// If not, see http://www.gnu.org/licenses/
+
+// Official SVN repository and contact information can be found at
+// http://code.google.com/p/dolphin-emu/
+
+#ifndef _ALSA_SOUND_STREAM_H
+#define _ALSA_SOUND_STREAM_H
+
+#include <alsa/asoundlib.h>
+
+#include "Common.h"
+#include "SoundStream.h"
+
+#include "Thread.h"
+
+#define HAVE_ALSA 1
+
+class AlsaSound : public SoundStream
+{
+#if defined(HAVE_ALSA) && HAVE_ALSA
+public:
+	AlsaSound(CMixer *mixer);
+	virtual ~AlsaSound();
+
+	virtual bool Start();
+	virtual void SoundLoop();
+	virtual void Stop(); 
+
+	static bool isValid() {
+		return true;
+	}
+	virtual bool usesMixer() const { 
+		return true; 
+	}
+
+	virtual void Update();
+
+private:
+	bool AlsaInit();
+	void AlsaShutdown();
+
+	u8 *mix_buffer;
+	Common::Thread *thread;
+	// 0 = continue
+	// 1 = shutdown
+	// 2 = done shutting down.
+	volatile int thread_data;
+
+	snd_pcm_t *handle;
+#else
+public:
+	AlsaSound(CMixer *mixer) : SoundStream(mixer) {}
+#endif
+};
+
+#endif
+