file_cast.h

//-*-C++-*-
/***************************************************************************
 *
 *   Copyright (C) 2009 by Willem van Straten
 *   Licensed under the Academic Free License version 2.1
 *
 ***************************************************************************/
// psrchive/Util/units/file_cast.h
 
#ifndef __UTILS_UNITS_FILE_CAST_H
#define __UTILS_UNITS_FILE_CAST_H
 
#include "FilePtr.h"
#include <memory>
 
template<typename T>
T* hard_const_cast (const T* x)
{
  return const_cast<T*> (x);
}
 
template<typename To, typename From>
To* file_cast (const From* from)
{
  FilePtr temp = tmpfile();
  if (!temp)
    throw Error (FailedSys, "file_cast", "tmpfile");
  
  from->unload (temp);
  rewind (temp);
 
  std::unique_ptr<To> to (new To);
 
  hard_const_cast(to.get())->load (temp);
 
  return to.release();
}
 
template<typename To, typename From>
To* dynamic_file_cast (From* from)
{
  To* to = dynamic_cast<To*>( from );
  if (to)
    return to;
 
  return file_cast<To>(from);
}
 
#endif