successor.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2021 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
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The above copyright notice and this permission notice shall be included in all
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******************************************************************************/
 
#ifndef ETL_SUCCESSOR_INCLUDED
#define ETL_SUCCESSOR_INCLUDED
 
#include "platform.h"
#include "error_handler.h"
#include "exception.h"
#include "file_error_numbers.h"
#include "nullptr.h"
 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  class successor_exception : public etl::exception
  {
  public:
 
    successor_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception(reason_, file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class successor_invalid : public etl::successor_exception
  {
  public:
 
    successor_invalid(string_type file_name_, numeric_type line_number_)
      : etl::successor_exception(ETL_ERROR_TEXT("successor:invalid", ETL_SUCCESSOR_FILE_ID"A"), file_name_, line_number_)
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class successor
  {
  public:
 
    typedef T successor_type;
 
    //*************************************************************************
    //*************************************************************************
    successor()
      : p_successor(ETL_NULLPTR)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    successor(successor_type& s)
      : p_successor(&s)
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    void set_successor(successor_type& s)
    {
      p_successor = &s;
    }
 
#if ETL_CPP11_SUPPORTED
    //*************************************************************************
    //*************************************************************************
    template <typename... TSuccessors>
    void set_successor(successor_type& s, TSuccessors&... rest)
    {
      set_successor(s);
      s.set_successor(rest...);
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    template <typename TSuccessor>
    void append_successor(TSuccessor& s)
    {
      if (has_successor())
      {
        get_successor().append_successor(s);
      }
      else
      {
        set_successor(s);
      }
    }
 
#if ETL_CPP11_SUPPORTED
    //*************************************************************************
    //*************************************************************************
    template <typename TSuccessor, typename... TSuccessors>
    void append_successor(TSuccessor& s, TSuccessors&... rest)
    {
      if (has_successor())
      {
        get_successor().append_successor(s);
        get_successor().append_successor(rest...);
      }
      else
      {
        set_successor(s);
        append_successor(rest...);
      }
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    void clear_successor()
    {
      p_successor = ETL_NULLPTR;
    }
 
    //*************************************************************************
    //*************************************************************************
    void clear_successor_chain()
    {
      if (has_successor())
      {
        get_successor().clear_successor_chain();
        clear_successor();
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    successor_type& get_successor() const
    {
      ETL_ASSERT(has_successor(), ETL_ERROR(successor_invalid));
 
      return *p_successor;
    }
 
    //*************************************************************************
    //*************************************************************************
    bool has_successor() const
    {
      return (p_successor != ETL_NULLPTR);
    }
 
  private:
 
    successor_type* p_successor;
  };
} // namespace etl
 
#endif