lists.cpp

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2016-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#if defined(OS_USE_OS_APP_CONFIG_H)
#include <cmsis-plus/os-app-config.h>
#endif
 
#include <cmsis-plus/utils/lists.h>
 
#include <cmsis-plus/diag/trace.h>
 
// ----------------------------------------------------------------------------
 
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wmissing-include-dirs"
#endif
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace utils
  {
    // ========================================================================
 
    void
    static_double_list_links::unlink (void)
    {
      // Check if not already unlinked.
      if (unlinked ())
        {
          assert (prev_ == nullptr);
#if defined(OS_TRACE_UTILS_LISTS)
          trace::printf ("%s() %p nop\n", __func__, this);
#endif
          return;
        }
 
#if defined(OS_TRACE_UTILS_LISTS)
      trace::printf ("%s() %p \n", __func__, this);
#endif
 
      // Make neighbours point to each other.
      prev_->next_ = next_;
      next_->prev_ = prev_;
 
      // Nullify both pointers in the unlinked node.
      prev_ = nullptr;
      next_ = nullptr;
    }
 
    // ========================================================================
 
    void
    static_double_list::clear (void)
    {
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
      head_.next (const_cast<static_double_list_links*> (&head_));
      head_.prev (const_cast<static_double_list_links*> (&head_));
#pragma GCC diagnostic pop
    }
 
    void
    static_double_list::insert_after (static_double_list_links& node,
                                      static_double_list_links* after)
    {
#if defined(OS_TRACE_UTILS_LISTS)
      trace::printf ("%s() n=%p after %p\n", __func__, &node, after);
#endif
 
      // Unlinked nodes must have both pointers null.
      // If not, most probably the node was already linked.
      // Or the memory is corrupted.
      assert (node.prev () == nullptr);
      assert (node.next () == nullptr);
 
      // The `after` node must be linked. Only the `next` pointer is
      // tested, since only it is used.
      assert (after->next () != nullptr);
 
      // Make the new node point to its neighbours.
      node.prev (after);
      node.next (after->next ());
 
      // Make the neighbours point to the node. The order is important.
      after->next ()->prev (&node);
      after->next (&node);
    }
 
    // ========================================================================
 
    double_list::double_list ()
    {
#if defined(OS_TRACE_UTILS_LISTS_CONSTRUCT) || defined(OS_TRACE_UTILS_LISTS)
      trace::printf ("%s() %p \n", __func__, this);
#endif
 
      clear ();
    }
 
    double_list::~double_list ()
    {
#if defined(OS_TRACE_UTILS_LISTS_CONSTRUCT) || defined(OS_TRACE_UTILS_LISTS)
      trace::printf ("%s() %p \n", __func__, this);
#endif
 
      assert (empty ());
    }
 
  } /* namespace utils */
} /* namespace os */
 
// ----------------------------------------------------------------------------