media-access-facade.hpp

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/*
  MEDIA-ACCESS-FACADE.hpp  -  functions for querying media file and channels.

   Copyright (C)
     2008,            Hermann Vosseler <Ichthyostega@web.de>

  **Lumiera** 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 2 of the License, or (at your
  option) any later version. See the file COPYING for further details.

*/


#ifndef VAULT_INTERFACE_MEDIA_ACCESS_FACADE_H
#define VAULT_INTERFACE_MEDIA_ACCESS_FACADE_H


#include "lib/error.hpp"
#include "lib/depend.hpp"
#include "lib/time/timevalue.hpp"

#include <string>



namespace vault {
  
  using lib::time::Duration;
  using std::string;
  
  struct MediaDesc;
  struct ChanDesc;
  
  
  /**************************************************************/
  class MediaAccessFacade
    {
    public:
      typedef void* ChanHandle;
      
      static lib::Depend<MediaAccessFacade> instance;
      
      virtual MediaDesc& queryFile (string const& name)  const;
      
      virtual ChanDesc queryChannel (MediaDesc&, uint chanNo)  const;
      
      virtual ~MediaAccessFacade () {}
    };
  
  
  struct MediaDesc
    {
      Duration length;
      
      MediaDesc() : length(Duration::NIL) { }
    };
  
  
  
  
  struct ChanDesc
    {
      const char* chanID;
      
      const char* codecID;
      
      MediaAccessFacade::ChanHandle handle;
      
      ChanDesc (const char* chanName=0, const char* codec=0, 
                MediaAccessFacade::ChanHandle h=0)
        : chanID(chanName),
          codecID(codec),
          handle(h)
        { }
    };
  
} // namespace vault


namespace backend_interface {
  
  using vault::MediaAccessFacade;
  using vault::MediaDesc;
  using vault::ChanDesc;
  
} // namespace backend_interface
#endif