////////////////////////////////////////////////////////////////////////////////

//   Author:    Andy Rushton
//   Copyright: (c) Southampton University 1999-2004
//              (c) Andy Rushton           2004-2009
//   License:   BSD License, see ../docs/license.html

//   format: magic_key [ data ]

////////////////////////////////////////////////////////////////////////////////
#include "persistent_int.hpp"

namespace stlplus
{

  ////////////////////////////////////////////////////////////////////////////////

  template<typename T>
  void dump_xref(dump_context& context, const T* const data)
    throw(persistent_dump_failed)
  {
    // register the address and get the magic key for it
    std::pair<bool,unsigned> mapping = context.pointer_map(data);
    // if this is the first view of this pointer, simply throw an exception
    if (!mapping.first) throw persistent_dump_failed("tried to dump a cross-reference not seen before");
    // otherwise, just dump the magic key
    dump_unsigned(context,mapping.second);
  }

  ////////////////////////////////////////////////////////////////////////////////>

  template<typename T>
  void restore_xref(restore_context& context, T*& data)
    throw(persistent_restore_failed)
  {
    // Note: I do not try to delete the old data because this is a cross-reference
    // get the magic key
    unsigned magic = 0;
    restore_unsigned(context,magic);
    // now lookup the magic key to see if this pointer has already been restored
    // null pointers are always flagged as already restored
    std::pair<bool,void*> address = context.pointer_map(magic);
    // if this is the first view of this pointer, simply throw an exception
    if (!address.first) throw persistent_restore_failed("tried to restore a cross-reference not seen before");
    // seen before, so simply assign the old address
    data = (T*)address.second;
  }

  ////////////////////////////////////////////////////////////////////////////////

} // end namespace stlplus