read_from_file.h

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//
//
#ifndef __stir_IO_read_from_file_H__
#define __stir_IO_read_from_file_H__
/*
    Copyright (C) 2006 - 2008-10-01, Hammersmith Imanet Ltd
    Copyright (C) 2011-07-01 - 2013, Kris Thielemans
    This file is part of STIR.
 
    SPDX-License-Identifier: Apache-2.0
 
    See STIR/LICENSE.txt for details
*/
#include "stir/IO/InputFileFormatRegistry.h"
#include "stir/unique_ptr.h"
 
START_NAMESPACE_STIR


template <class DataT, class FileT>
inline unique_ptr<DataT>
read_from_file(const FileSignature& signature, FileT file)
{
  using hierarchy_base_type = typename DataT::hierarchy_base_type;
  const InputFileFormat<hierarchy_base_type>& factory
      = InputFileFormatRegistry<hierarchy_base_type>::default_sptr()->find_factory(signature, file);
  auto uptr(factory.read_from_file(file));
  // There is no dynamic_pointer_cast for unique_ptr
  // See https://stackoverflow.com/questions/11002641/dynamic-casting-for-unique-ptr why
  // We use a trick mentioned in that link
  auto data_ptr = dynamic_cast<DataT*>(uptr.get());
  if (!data_ptr)
    {
      // TODO improve on the following cryptic error message
      error("data read from file is an incorrect type");
    }
  // get rid of the original uptr (but not the object pointed to) and create a new one
  uptr.release();
  return unique_ptr<DataT>(data_ptr);
}


template <class DataT, class FileT>
inline unique_ptr<DataT>
read_from_file(FileT file)
{
  const FileSignature signature(file);
  return read_from_file<DataT>(signature, file);
}
 
END_NAMESPACE_STIR
 
#endif