etl/intrusive_links.h

///\file

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
http://www.etlcpp.com

Copyright(c) 2016 jwellbelove

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/

#ifndef __ETL_INTRUSIVE_LINKS__
#define __ETL_INTRUSIVE_LINKS__

#include "nullptr.h"
#include "type_traits.h"
#include "exception.h"
#include "error_handler.h"

#undef ETL_FILE
#define ETL_FILE "23"

namespace etl
{
  namespace link_option
  {
    enum
    {
      DEFAULT = 0,
      AUTO    = 1,
      SAFE    = 2
    };
  };

  //***************************************************************************
  /// Deque full exception.
  ///\ingroup deque
  //***************************************************************************
  class link_exception : public etl::exception
  {
  public:

    link_exception(string_type file_name, numeric_type line_number)
      : exception(ETL_ERROR_TEXT("link:still linked", ETL_FILE"A"), file_name, line_number)
    {
    }
  };

  //***************************************************************************
  /// A forward link.
  //***************************************************************************
  template <const size_t ID_ = 0>
  struct forward_link
  {
    enum
    {
      ID = ID_
    };

    void clear()
    {
      etl_next = nullptr;
    }

    forward_link* etl_next;
  };

  // Reference, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link(TLink& lhs, TLink& rhs)
  {
    lhs.etl_next = &rhs;
  }

  // Reference, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link_insert(TLink& lhs, TLink& rhs)
  {
    rhs.etl_next = lhs.etl_next;
    lhs.etl_next = &rhs;
  }

  // Pointer, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link(TLink* lhs, TLink* rhs)
  {
    if (lhs != nullptr)
    {
      lhs->etl_next = rhs;
    }
  }

  // Pointer, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link_insert(TLink* lhs, TLink* rhs)
  {
    if (lhs != nullptr)
    {
      if (rhs != nullptr)
      {
          rhs->etl_next = lhs->etl_next;
      }

      lhs->etl_next = rhs;
    }
  }

  // Reference, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link(TLink& lhs, TLink* rhs)
  {
    lhs.etl_next = rhs;
  }

  // Reference, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link_insert(TLink& lhs, TLink* rhs)
  {
    if (rhs != nullptr)
    {
      rhs->etl_next = lhs.etl_next;
    }

    lhs.etl_next = rhs;
  }

  // Pointer, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link(TLink* lhs, TLink& rhs)
  {
    if (lhs != nullptr)
    {
      lhs->etl_next = &rhs;
    }
  }

  // Pointer, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  link_insert(TLink* lhs, TLink& rhs)
  {
    if (lhs != nullptr)
    {
      rhs.etl_next  = lhs->etl_next;
      lhs->etl_next = &rhs;
    }
  }

  // Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  unlink_after(TLink& node)
  {
    if (node.etl_next != nullptr)
    {
      node.etl_next = node.etl_next->etl_next;
    }
  }

  // Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::forward_link<TLink::ID> >::value, void>::type
  unlink_after(TLink* node)
  {
    if (node != nullptr)
    {
      if (node->etl_next != nullptr)
      {
        node->etl_next = node.etl_next->etl_next;
      }
    }
  }

  //***************************************************************************
  /// A bidirectional link.
  //***************************************************************************
  template <const size_t ID_ = 0, const int OPTION_ = etl::link_option::DEFAULT>
  struct bidirectional_link
  {
    enum
    {
      ID     = ID_,
      OPTION = OPTION_
    };

    void clear()
    {
      etl_previous = nullptr;
      etl_next     = nullptr;
    }

    bidirectional_link* etl_previous;
    bidirectional_link* etl_next;
  };

  //******************************************************************
  // Specialisation for auto unlinked option.
  // When this link is destroyed it will automatically unlink itself.
  //******************************************************************
  template <const size_t ID_>
  struct bidirectional_link<ID_, etl::link_option::AUTO>
  {
    enum
    {
      ID     = ID_,
      OPTION = etl::link_option::AUTO_UNLINK
    };

    ~bidirectional_link()
    {
      // Connect the previous link with the next.
      if (etl_previous != nullptr)
      {
        etl_previous->etl_next = etl_next;
      }

      // Connect the next link with the previous.
      if (etl_next != nullptr)
      {
        etl_next->etl_previous = etl_previous;
      }
    }

    void clear()
    {
      etl_previous = nullptr;
      etl_next     = nullptr;
    }

    bidirectional_link* etl_previous;
    bidirectional_link* etl_next;
  };

  //******************************************************************
  // Specialisation for safe unlinked option.
  // An error will be generated if the links are valid when the object
  // is destroyed.
  //******************************************************************
  template <const size_t ID_>
  struct bidirectional_link<ID_, etl::link_option::SAFE>
  {
    enum
    {
      ID     = ID_,
      OPTION = etl::link_option::AUTO_UNLINK
    };

    ~bidirectional_link()
    {
      ETL_ASSERT(etl_previous == nullptr, ETL_ERROR(link_exception));
      ETL_ASSERT(etl_next     == nullptr, ETL_ERROR(link_exception));
    }

    void clear()
    {
      etl_previous = nullptr;
      etl_next     = nullptr;
    }

    bidirectional_link* etl_previous;
    bidirectional_link* etl_next;
  };

  // Reference, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  link(TLink& lhs, TLink& rhs)
  {
    lhs.etl_next     = &rhs;
    rhs.etl_previous = &lhs;
  }

  // Pointer, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  link(TLink* lhs, TLink* rhs)
  {
    if (lhs != nullptr)
    {
      lhs->etl_next = rhs;
    }

    if (rhs != nullptr)
    {
      rhs->etl_previous = lhs;
    }
  }

  // Reference, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  link(TLink& lhs, TLink* rhs)
  {
    lhs.etl_next = rhs;

    if (rhs != nullptr)
    {
      rhs->etl_previous = &lhs;
    }
  }

  // Pointer, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  link(TLink* lhs, TLink& rhs)
  {
    if (lhs != nullptr)
    {
      lhs->etl_next = &rhs;
    }

    rhs.etl_previous = lhs;
  }

  // Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  unlink(TLink& node)
  {
    if (node.etl_next != nullptr)
    {
      node.etl_next->etl_previous = node.etl_previous;
    }

    if (node.etl_previous != nullptr)
    {
      node.etl_previous->etl_next = node.etl_next;
    }
  }

  // Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::bidirectional_link<TLink::ID, TLink::OPTION> >::value, void>::type
  unlink(TLink* node)
  {
    if (node != nullptr)
    {
      if (node->etl_next != nullptr)
      {
        node->etl_next->etl_previous = node->etl_previous;
      }

      if (node->etl_previous != nullptr)
      {
        node->etl_previous->etl_next = node->etl_next;
      }
    }
  }

  //***************************************************************************
  /// A tree link.
  //***************************************************************************
  template <const size_t ID_ = 0>
  struct tree_link
  {
    enum
    {
      ID = ID_
    };

    void clear()
    {
      etl_parent = nullptr;
      etl_left   = nullptr;
      etl_right  = nullptr;
    }

    tree_link* etl_parent;
    tree_link* etl_left;
    tree_link* etl_right;
  };

  // Reference, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_left(TLink& parent, TLink& leaf)
  {
    parent.etl_left = &leaf;
    leaf.etl_parent = &parent;
  }

  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_right(TLink& parent, TLink& leaf)
  {
    parent.etl_right = &leaf;
    leaf.etl_parent  = &parent;
  }

  // Pointer, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_left(TLink* parent, TLink* leaf)
  {
    if (parent != nullptr)
    {
      parent->etl_left = leaf;
    }

    if (leaf != nullptr)
    {
      leaf->etl_parent = parent;
    }
  }

  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_right(TLink* parent, TLink* leaf)
  {
    if (parent != nullptr)
    {
      parent->etl_right = leaf;
    }

    if (leaf != nullptr)
    {
      leaf->etl_parent = parent;
    }
  }

  // Reference, Pointer
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_left(TLink& parent, TLink* leaf)
  {
    parent.etl_left = leaf;

    if (leaf != nullptr)
    {
      leaf->etl_parent = &parent;
    }
  }

  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_right(TLink& parent, TLink* leaf)
  {
    parent.etl_right = leaf;

    if (leaf != nullptr)
    {
      leaf->etl_parent = &parent;
    }
  }

  // Pointer, Reference
  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_left(TLink* parent, TLink& leaf)
  {
    if (parent != nullptr)
    {
      parent->etl_left = &leaf;
    }

    leaf.etl_parent = parent;
  }

  template <typename TLink>
  typename etl::enable_if<etl::is_same<TLink, etl::tree_link<TLink::ID> >::value, void>::type
  link_right(TLink* parent, TLink& leaf)
  {
    if (parent != nullptr)
    {
      parent->etl_right = &leaf;
    }

    leaf.etl_parent = parent;
  }
}

#undef ETL_FILE
#endif