audlinux_alsa.h

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

/* ***** BEGIN LICENSE BLOCK *****
 * Version: RCSL 1.0/RPSL 1.0 
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 * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. 
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 * The contents of this file, and the files included with this file, are 
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 * Version 1.0 (the "RPSL") available at 
 * http://www.helixcommunity.org/content/rpsl unless you have licensed 
 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
 * directly from RealNetworks.  You may not use this file except in 
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 * applicable to this file, the RCSL.  Please see the applicable RPSL or 
 * RCSL for the rights, obligations and limitations governing use of the 
 * contents of the file.  
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 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the portions 
 * it created. 
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 * This file, and the files included with this file, is distributed and made 
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 * ***** END LICENSE BLOCK ***** */

#ifndef _AUDLINUXALSA
#define _AUDLINUXALSA

//-----------------------------------------------
// System includes.
//-----------------------------------------------
#if defined( _LINUX ) 
//&& !defined( __powerpc__ )  && !defined __alpha && !defined __sparc__
#include <alsa/asoundlib.h>
//#include "linux/soundcard.h"
//#elif defined(__powerpc__)
//#include "sys/soundcard.h"
//#elif defined _NETBSD
//#include "soundcard.h"
//#elif defined _SCO_UW
//#include <sys/soundcard.h>
//#elif defined _FREEBSD || defined __alpha || defined __sparc__
//#include "machine/soundcard.h"
//#else 
//#include "machine/soundcard.h"
#endif

//------------------------------------------------
// local includes
//------------------------------------------------
#include "hxcom.h"
#include "hxslist.h"
#include "audUnix.h"

class CAudioOutLinuxAlsa : public CAudioOutUNIX
{
  public:
    CAudioOutLinuxAlsa();
    virtual ~CAudioOutLinuxAlsa();

  protected:

    
    //-------------------------------------------------------
    //
    // Pure virtuals from CAudioOutUNIX.
    //
    //-------------------------------------------------------
    virtual INT16 _Imp_GetAudioFd(void);

    //This ones important.
    virtual UINT64 _GetBytesActualyPlayed(void) const;

    //Devic specific method to set the audio device characteristics. Sample rate,
    //bits-per-sample, etc.
    //Method *must* set member vars. m_unSampleRate and m_unNumChannels.
    virtual HX_RESULT _SetDeviceConfig( const HXAudioFormat* pFormat );

    //Device specific method to test wether or not the device supports the
    //give sample rate. If the device can not be opened, or otherwise tested,
    //it should return RA_AOE_DEVBUSY.
    virtual HX_RESULT _CheckSampleRate( ULONG32 ulSampleRate );
    virtual HX_RESULT _CheckFormat( const HXAudioFormat* pFormat );

    //Device specific method to write bytes out to the audiodevice and return a
    //count of bytes written.
    virtual HX_RESULT _WriteBytes( UCHAR* buffer, ULONG32 ulBuffLength, LONG32& lCount );

    //Device specific methods to open/close the mixer and audio devices.
    virtual HX_RESULT _OpenAudio();
    virtual HX_RESULT _CloseAudio();
    virtual HX_RESULT _OpenMixer();
    virtual HX_RESULT _CloseMixer();

    //Device specific method to reset device and return it to a state that it
    //can accept new sample rates, num channels, etc.
    virtual HX_RESULT _Reset();
    virtual HX_RESULT _Pause();
    virtual HX_RESULT _Resume();

    //Device specific method to get/set the devices current volume.
    virtual UINT16    _GetVolume() const;
    virtual HX_RESULT _SetVolume(UINT16 volume);

    //Device specific method to drain a device. This should play the remaining
    //bytes in the devices buffer and then return.
    virtual HX_RESULT _Drain();

    //Device specific method to return the amount of room available on the
    //audio device that can be written without blocking.
    virtual HX_RESULT _GetRoomOnDevice( ULONG32& ulBytes) const;

    //A mehtod to let us know if the hardware supports puase/resume.
    //We can use this to remove unneeded memcpys and other expensive
    //operations. The default implementation is 'No, not supported'.
    virtual BOOL _HardwarePauseSupported() const;

    //-----------------------------------------------
    // Some helper methods.
    //-----------------------------------------------
    void _SyncUpTimeStamps(ULONG32 lCount=0);
    
  private:
  
    //protect the unintentional copy ctor.
    CAudioOutLinuxAlsa( const CAudioOutLinuxAlsa & );  //Not implemented.

    ULONG32 m_ulLastTimeStamp;
    ULONG32 m_ulTickCount;
    UINT64  m_ulPausePosition;
    UINT64  m_ulLastBytesPlayed;

    snd_pcm_t *pcm_handle;
    snd_mixer_t *mixer_handle;
    //  snd_pcm_stream_t stream;// = SND_PCM_STREAM_PLAYBACK;

    snd_pcm_hw_params_t *hwparams;
    snd_pcm_sw_params_t *swparams;

    size_t m_frameBytes;
    snd_pcm_status_t *status;
    long channels, samplesize, blocksize;
    mutable BOOL m_bHasHardwarePause;
    mutable BOOL m_bHasHardwareResume;
};


#endif  //_AUDIOOUTLINUXALSA