pc_base.h

/* 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