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engines/kyra/sound/drivers/pc_base.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 KYRA_SOUND_PCDRIVER_H
+#define KYRA_SOUND_PCDRIVER_H
+
+#include "kyra/resource/resource.h"
+
+namespace Audio {
+	class Mixer;
+}
+
+namespace Kyra {
+
+class PCSoundDriver {
+public:
+	PCSoundDriver() : _soundData(0), _soundDataSize(0) {}
+	virtual ~PCSoundDriver() {}
+
+	virtual void initDriver() = 0;
+	virtual void setSoundData(uint8 *data, uint32 size) = 0;
+	virtual void startSound(int track, int volume) = 0;
+	virtual bool isChannelPlaying(int channel) const = 0;
+	virtual void stopAllChannels() = 0;
+
+	virtual int getSoundTrigger() const { return 0; }
+	virtual void resetSoundTrigger() {}
+
+	virtual void setMusicVolume(uint8 volume) = 0;
+	virtual void setSfxVolume(uint8 volume) = 0;
+
+	// AdLiB (Kyra 1) specific
+	virtual void setSyncJumpMask(uint16) {}
+
+protected:
+	uint8 *getProgram(int progId) {
+		// Safety check: invalid progId would crash.
+		if (progId < 0 || progId >= (int32)_soundDataSize / 2)
+			return nullptr;
+
+		const uint16 offset = READ_LE_UINT16(_soundData + 2 * progId);
+
+		// In case an invalid offset is specified we return nullptr to
+		// indicate an error. 0xFFFF seems to indicate "this is not a valid
+		// program/instrument". However, 0 is also invalid because it points
+		// inside the offset table itself. We also ignore any offsets outside
+		// of the actual data size.
+		// The original does not contain any safety checks and will simply
+		// read outside of the valid sound data in case an invalid offset is
+		// encountered.
+		if (offset == 0 || offset >= _soundDataSize) {
+			return nullptr;
+		} else {
+			return _soundData + offset;
+		}
+	}
+
+	uint8 *_soundData;
+	uint32 _soundDataSize;
+
+public:
+	static PCSoundDriver *createAdLib(Audio::Mixer *mixer, int version);
+#ifdef ENABLE_EOB
+	static PCSoundDriver *createPCSpk(Audio::Mixer *mixer, bool pcJRMode);
+#endif
+};
+
+} // End of namespace Kyra
+
+#endif