IInterface.h

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// $Id: IInterface.h,v 1.14 2008/01/29 08:28:14 marcocle Exp $
#ifndef GAUDIKERNEL_IINTERFACE_H
#define GAUDIKERNEL_IINTERFACE_H

// Include files 

#include "GaudiKernel/Kernel.h"
#include "GaudiKernel/StatusCode.h"
#include <ostream>

class InterfaceID {
public:
  InterfaceID( unsigned long lid ) : m_id( lid & 0xFFFF ),
                                     m_major_ver( (lid & 0xFF000000)>>24 ),
                                     m_minor_ver( (lid & 0xFF0000)>> 16 ) { }
  InterfaceID( unsigned long id, unsigned long major, unsigned long minor = 0)
    : m_id( id ), m_major_ver( major ), m_minor_ver( minor ) { }
  InterfaceID( const char* name, unsigned long major, unsigned long minor = 0)
    : m_id( hash32(name) ), m_major_ver( major ), m_minor_ver( minor ) { }
  ~InterfaceID() { }
  operator unsigned long() const {
    return (m_major_ver << 24) + (m_minor_ver << 16) + m_id;
  }
  unsigned long id() const { return m_id; }
  unsigned long majorVersion() const { return m_major_ver; }
  unsigned long minorVersion() const { return m_minor_ver; }
  bool versionMatch( const InterfaceID& iid ) const { 
    return ( id() == iid.id() &&
             majorVersion() == iid.majorVersion() &&
             minorVersion() >= iid.minorVersion() );
  }
  bool fullMatch( const InterfaceID& iid ) const { 
    return ( id() == iid.id() &&
             majorVersion() == iid.majorVersion() &&
             minorVersion() == iid.minorVersion() );
  }
  bool operator == (const InterfaceID& iid ) const { return fullMatch(iid); }
  unsigned int hash32(const char* key) {
    unsigned int hash;
    const char* k;
    for (hash = 0, k = key; *k; k++) {
      hash += *k; hash += (hash << 10); hash ^= (hash >> 6); 
    }
    hash += (hash << 3); hash ^= (hash >> 11); hash += (hash << 15);
    return hash;
  }
private:
  friend std::ostream& operator << ( std::ostream&, const InterfaceID&);
  unsigned long m_id;
  unsigned long m_major_ver;
  unsigned long m_minor_ver;
};

// typedef InterfaceID IID; removed: it collides with windows system typename

// Interface ID
static const InterfaceID IID_IInterface(1,0,0);

class IInterface        {
  public:
  static const InterfaceID& interfaceID() { return IID_IInterface; }

  virtual ~IInterface() { }

  virtual StatusCode queryInterface(const InterfaceID& riid,
                                    void** ppvInterface) = 0;

  virtual unsigned long addRef() = 0;

  virtual unsigned long release() = 0;

  enum Status   {
    SUCCESS = 1,
    NO_INTERFACE,
    VERSMISMATCH,
    LAST_ERROR
  };
};

template <class I> 
bool isValidInterface( I* i) {
  void* ii;
  StatusCode sc =  i->queryInterface( I::interfaceID(), &ii);
  return sc.isSuccess();
}

inline std::ostream& operator << ( std::ostream& s, const InterfaceID& id) {
    s << "IID_" << id.m_id;
    return s;
}

template <class DEST,class SRC>
inline DEST** pp_cast(SRC** ptr){
  return reinterpret_cast<DEST**>(ptr);
}
#endif  // GAUDIKERNEL_IINTERFACE_H