// $Id: Timer_Wheel_T.cpp,v 1.34 1999/07/03 18:26:24 schmidt Exp $

#ifndef ACE_TIMER_WHEEL_T_C
#define ACE_TIMER_WHEEL_T_C

#define ACE_BUILD_DLL

#include "ace/Timer_Wheel_T.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "ace/High_Res_Timer.h"

ACE_RCSID(ace, Timer_Wheel_T, "$Id: Timer_Wheel_T.cpp,v 1.34 1999/07/03 18:26:24 schmidt Exp $")

// Constructor that takes in a <wheel>, a reference to the timer queue

template <class TYPE, class FUNCTOR, class ACE_LOCK>
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::ACE_Timer_Wheel_Iterator_T (ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK> &wheel)
  : timer_wheel_ (wheel)
{
  this->first();
  // Nothing
}

template <class TYPE, class FUNCTOR, class ACE_LOCK>
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::~ACE_Timer_Wheel_Iterator_T (void)
{
}

// Positions the iterator at the first node in the timing wheel

template <class TYPE, class FUNCTOR, class ACE_LOCK> void
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::first (void)
{
  for (this->pos_ = 0;
       this->pos_ < this->timer_wheel_.wheel_size_;
       this->pos_++)
    {
      // Skip over empty entries
      if (this->timer_wheel_.wheel_[this->pos_]->get_next () 
          != this->timer_wheel_.wheel_[this->pos_])
        {
          this->list_item_ =
            this->timer_wheel_.wheel_[this->pos_]->get_next ();
          return;
        }
    }

  // The queue is empty if we are here
  this->list_item_ = 0;
}

// Positions the iterator at the next node in list or goes to the next
// list

template <class TYPE, class FUNCTOR, class ACE_LOCK> void
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::next (void)
{
  if (this->isdone ())
    return;

  this->list_item_ =
    this->list_item_->get_next ();

  // If there is no more in the current list, go to the next
  if (this->list_item_ == this->timer_wheel_.wheel_[this->pos_])
    {
      for (this->pos_++;
           this->pos_ < this->timer_wheel_.wheel_size_;
           this->pos_++)
        {
          // Check for an empty entry
          if (this->timer_wheel_.wheel_[this->pos_]->get_next () 
              != this->timer_wheel_.wheel_[this->pos_])
            {
              this->list_item_ =
                this->timer_wheel_.wheel_[this->pos_]->get_next ();
              return;
            }
        }

      this->list_item_ = 0;
    }
}

// Returns true when we are at the end (when list_item_ == 0)

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::isdone (void)
{
  return this->list_item_ == 0;
}

// Returns the node at the current position in the sequence

template <class TYPE, class FUNCTOR, class ACE_LOCK> ACE_Timer_Node_T<TYPE> *
ACE_Timer_Wheel_Iterator_T<TYPE, FUNCTOR, ACE_LOCK>::item (void)
{
  if (this->isdone ())
    return 0;

  return this->list_item_;
}

// Constructor that sets up the timing wheel and also may preallocate
// some nodes on the free list

template <class TYPE, class FUNCTOR, class ACE_LOCK>
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::ACE_Timer_Wheel_T (size_t wheelsize,
                                                           size_t resolution,
                                                           size_t prealloc,
                                                           FUNCTOR *upcall_functor,
                                                           ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist)
  : ACE_Timer_Queue_T<TYPE,FUNCTOR,ACE_LOCK> (upcall_functor, freelist),
    wheel_size_ (wheelsize),
    resolution_ (resolution),
    earliest_pos_ (0)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::ACE_Timer_Wheel_T");
  size_t i;

  this->gettimeofday (ACE_OS::gettimeofday);

  // Create the timing wheel
  ACE_NEW (this->wheel_,
           ACE_Timer_Node_T<TYPE> *[wheelsize]);

  // Create the dummy nodes
  for (i = 0; i < wheelsize; i++)
    {
      ACE_Timer_Node_T<TYPE> *tempnode =
        this->alloc_node ();
      tempnode->set_next (tempnode);
      tempnode->set_prev (tempnode);
      this->wheel_[i] = tempnode;
    }

  // Do the preallocation
  this->free_list_->resize (prealloc);

  ACE_NEW (iterator_,
           WHEEL_ITERATOR (*this));
}

template <class TYPE, class FUNCTOR, class ACE_LOCK>
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::ACE_Timer_Wheel_T (FUNCTOR *upcall_functor,
                                                               ACE_Free_List<ACE_Timer_Node_T <TYPE> > *freelist)
  : ACE_Timer_Queue_T<TYPE,FUNCTOR,ACE_LOCK> (upcall_functor, freelist),
    wheel_size_ (ACE_DEFAULT_TIMER_WHEEL_SIZE),
    resolution_ (ACE_DEFAULT_TIMER_WHEEL_RESOLUTION),
    earliest_pos_ (0)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::ACE_Timer_Wheel_T");
  size_t i;

  this->gettimeofday (ACE_OS::gettimeofday);

  // Create the timing wheel
  ACE_NEW (this->wheel_,
           ACE_Timer_Node_T<TYPE> *[this->wheel_size_]);

  // Create the dummy nodes
  for (i = 0; i < this->wheel_size_; i++)
    {
      ACE_Timer_Node_T<TYPE> *tempnode = this->alloc_node ();
      tempnode->set_next (tempnode);
      tempnode->set_prev (tempnode);
      this->wheel_[i] = tempnode;
    }

  ACE_NEW (iterator_,
           WHEEL_ITERATOR (*this));
}

// Destructor just cleans up its memory

template <class TYPE, class FUNCTOR, class ACE_LOCK>
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::~ACE_Timer_Wheel_T (void)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::~ACE_Timer_Wheel_T");

  delete iterator_;

  for (size_t i = 0;
       i < this->wheel_size_;
       i++)
    {
      // delete nodes until only the dummy node is left
      while (this->wheel_[i]->get_next () != this->wheel_[i])
        {
          ACE_Timer_Node_T<TYPE> *next =
            this->wheel_[i]->get_next ();
          this->wheel_[i]->set_next (next->get_next ());
          next->get_next ()->set_prev (this->wheel_[i]);
          this->upcall_functor ().deletion (*this,
                                            next->get_type (),
                                            next->get_act ());
          this->free_node (next);
        }

      // and now delete the dummy node
      delete this->wheel_[i];
    }

  // finally delete the wheel
  delete [] this->wheel_;
}

// Checks to see if <earliest_pos> points to a empty list (then it is empty)

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::is_empty (void) const
{
  ACE_TRACE ("ACE_Timer_Wheel_T::is_empty");

  return this->wheel_[this->earliest_pos_]->get_next () == this->wheel_[this->earliest_pos_];
}

// Returns the first (earliest) node in the <wheel_>'s <earliest_pos_> list

template <class TYPE, class FUNCTOR, class ACE_LOCK> const ACE_Time_Value &
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::earliest_time (void) const
{
  ACE_TRACE ("ACE_Timer_Wheel_T::earliest_time");

  if (this->is_empty ())
    return ACE_Time_Value::zero;
  else
    return this->wheel_[this->earliest_pos_]->get_next ()->get_timer_value ();
}

// Create the node and pass it to reschedule.  Also check to see if
// the <earliest_pos> should be changed.

template <class TYPE, class FUNCTOR, class ACE_LOCK> long
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::schedule (const TYPE &type,
                                                  const void *act,
                                                  const ACE_Time_Value &delay,
                                                  const ACE_Time_Value &interval)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::schedule");
  ACE_MT (ACE_GUARD_RETURN (ACE_LOCK, ace_mon, this->mutex_, -1));

  ACE_Timer_Node_T<TYPE> *tempnode = this->alloc_node ();

  if (tempnode)
    {
      // Note that the timer_id is actually the pointer to the node

      // Set the details of the node
      tempnode->set (type,
                     act,
                     delay,
                     interval,
                     0,
                     0,
                     (long) tempnode);

      // Reschedule will insert it into the correct position
      this->reschedule (tempnode);

      return tempnode->get_timer_id ();
    }

  // Failure return
  errno = ENOMEM;
  return -1;
}

// Goes through every list in the wheel and if it finds a node with <type>
// then it removes the node and continues on looking for other nodes

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::cancel (const TYPE &type,
                                                    int dont_call_handle_close)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::cancel");
  ACE_MT (ACE_GUARD_RETURN (ACE_LOCK, ace_mon, this->mutex_, -1));

  int number_of_cancellations = 0;
  size_t i;

  // Walk through the wheel
  for (i = 0; i < this->wheel_size_; i++)
    {
      ACE_Timer_Node_T<TYPE> *curr = this->wheel_[i]->get_next ();

      // Walk through the list
      while (curr != this->wheel_[i])
        {
          if (curr->get_type () == type)
            {
              // Cancel it and remove it.
              number_of_cancellations++;

              // Detach it from the list
              ACE_Timer_Node_T<TYPE> *tempnode = curr;
              curr->get_prev ()->set_next (curr->get_next ());
              curr->get_next ()->set_prev (curr->get_prev ());

              // Go on to the next and delete the detached node
              curr = curr->get_next ();
              this->free_node (tempnode);
            }
          else
            curr = curr->get_next ();
        }
    }

  //  Look for a new earliest time

  // Defaults to zero.
  ACE_Time_Value earliest_time; 

  // Check every entry in the table
  for (i = 0; i < this->wheel_size_; i++)
    {
      // Skip empty entries
      if (this->wheel_[i]->get_next () != this->wheel_[i])
        {
          // if initialization or if the time is earlier
          if (earliest_time == ACE_Time_Value::zero
              || this->wheel_[i]->get_timer_value () < earliest_time)
            {
              earliest_time =
                this->wheel_[i]->get_next ()->get_timer_value ();
              this->earliest_pos_ = i;
            }
        }
    }

  if (dont_call_handle_close == 0)
    this->upcall_functor ().cancellation (*this,
                                          type);
  return number_of_cancellations;
}

// Takes the <timer_id> and casts it to a pointer.  Then it removes it
// from its neighbors

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::cancel (long timer_id,
                                                    const void **act,
                                                    int dont_call_handle_close)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::cancel");
  ACE_MT (ACE_GUARD_RETURN (ACE_LOCK, ace_mon, this->mutex_, -1));

  // Make sure we are getting a valid <timer_id>, not an error
  // returned by <schedule>.
  if (timer_id == -1)
    return 0;

  ACE_Timer_Node_T<TYPE> *node =
    (ACE_Timer_Node_T<TYPE> *) timer_id;

  // Check to see if the node looks like a true ACE_Timer_Node_T<TYPE>
  if (timer_id == node->get_timer_id ())
    {
      node->get_next ()->set_prev (node->get_prev ());
      node->get_prev ()->set_next (node->get_next ());

      if (act != 0)
        *act = node->get_act ();

      if (dont_call_handle_close == 0)
        this->upcall_functor ().cancellation (*this,
                                              node->get_type ());

      // Find out what position it is in.
      size_t pos = (node->get_timer_value ().usec () / this->resolution_) % this->wheel_size_;

      this->free_node (node);

      // Get the new earliest time if we have to

      if (pos == this->earliest_pos_)
        {
          ACE_Time_Value earliest_time; // defaults to zero

          // Check every entry in the table
          for (size_t i = 0; i < this->wheel_size_; i++)
            {
              // Skip empty entries
              if (this->wheel_[i]->get_next () != this->wheel_[i])
                {
                  // if initialization or if the time is earlier
                  if (earliest_time == ACE_Time_Value::zero
                      || this->wheel_[i]->get_timer_value () < earliest_time)
                    {
                      earliest_time =
                        this->wheel_[i]->get_next ()->get_timer_value ();
                      this->earliest_pos_ = i;
                    }
                }
            }
        }

      return 1;
    }

  // Didn't find it if we are here
  return 0;
}

// Dumps out some properties of this object

template <class TYPE, class FUNCTOR, class ACE_LOCK> void
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::dump (void) const
{
  ACE_TRACE ("ACE_Timer_Wheel_T::dump");
  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));

  ACE_DEBUG ((LM_DEBUG, ASYS_TEXT ("\nwheel_size_ = %d"), this->wheel_size_));
  ACE_DEBUG ((LM_DEBUG, ASYS_TEXT ("\nresolution_ = %d"), this->resolution_));
  ACE_DEBUG ((LM_DEBUG, ASYS_TEXT ("\nwheel_ = \n")));

  for (size_t i = 0; i < this->wheel_size_; i++)
    {
      ACE_DEBUG ((LM_DEBUG, ASYS_TEXT ("%d\n"), i));
      ACE_Timer_Node_T<TYPE> *temp = this->wheel_[i]->get_next ();
      while (temp != this->wheel_[i])
        {
          temp->dump ();
          temp = temp->get_next ();
        }
    }

  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
}

// Removes the earliest node and then find the new <earliest_pos_>

template <class TYPE, class FUNCTOR, class ACE_LOCK> ACE_Timer_Node_T<TYPE> *
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::remove_first (void)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::remove_first");

  // Remove the item
  ACE_Timer_Node_T<TYPE> *temp =
    this->wheel_[this->earliest_pos_]->get_next ();
  temp->get_prev ()->set_next (temp->get_next ());
  temp->get_next ()->set_prev (temp->get_prev ());

  ACE_Time_Value earliest_time;

  // Check every entry in the table for the new earliest item
  for (size_t i = 0; i < this->wheel_size_; i++)
    {
      // Check for an empty entry
      if (this->wheel_[i]->get_next () != this->wheel_[i])
        {
          // if initialization or if the time is earlier
          if (earliest_time == ACE_Time_Value::zero
              || this->wheel_[i]->get_timer_value () < earliest_time)
            {
              earliest_time =
                this->wheel_[i]->get_next ()->get_timer_value ();
              this->earliest_pos_ = i;
            }
        }
    }

  return temp;
}

// Returns the earliest node without removing it

template <class TYPE, class FUNCTOR, class ACE_LOCK> ACE_Timer_Node_T<TYPE> *
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::get_first (void)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::get_first");

  return this->wheel_[this->earliest_pos_]->get_next ();
}

// Takes an ACE_Timer_Node and inserts it into the correct position in
// the correct list.

template <class TYPE, class FUNCTOR, class ACE_LOCK> void
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::reschedule (ACE_Timer_Node_T<TYPE> *expired)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::reschedule");

  size_t pos =
    (expired->get_timer_value ().usec () / this->resolution_) % this->wheel_size_;

  // See if we need to update the earliest time
  if (this->earliest_time () == ACE_Time_Value::zero
      || expired->get_timer_value () < this->earliest_time ())
    this->earliest_pos_ = pos;

  // Insert time into dummy node.
  this->wheel_[pos]->set_timer_value (expired->get_timer_value ());
  ACE_Timer_Node_T<TYPE> *cursor =
    this->wheel_[pos]->get_next ();

  // Find position to insert
  while (cursor->get_timer_value () < expired->get_timer_value ())
    cursor = cursor->get_next ();

  // Insert
  expired->set_prev (cursor->get_prev ());
  expired->set_next (cursor);
  cursor->set_prev (expired);
  expired->get_prev ()->set_next (expired);
}

// Just return the iterator

template <class TYPE, class FUNCTOR, class ACE_LOCK> ACE_Timer_Queue_Iterator_T<TYPE, FUNCTOR, ACE_LOCK> &
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::iter (void)
{
  this->iterator_->first ();
  return *this->iterator_;
}

// Dummy version of expire to get rid of warnings in Sun CC 4.2

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::expire ()
{
  return ACE_Timer_Queue_T<TYPE,FUNCTOR,ACE_LOCK>::expire ();
}

// Specialized expire which expires in total order.  It is optimized
// by keeping track of the list with the earliest element and the next
// earliest list.  It then goes through the earliest list until it can
// switch to the second list.  it keeps going until it finishes with
// everything before the <cur_time>

template <class TYPE, class FUNCTOR, class ACE_LOCK> int
ACE_Timer_Wheel_T<TYPE, FUNCTOR, ACE_LOCK>::expire (const ACE_Time_Value &cur_time)
{
  ACE_TRACE ("ACE_Timer_Wheel_T::expire");
  ACE_MT (ACE_GUARD_RETURN (ACE_LOCK, ace_mon, this->mutex_, -1));

  int number_of_timers_expired = 0;
  size_t i;
  size_t earliest = this->wheel_size_;
  ACE_Time_Value earliest_time = cur_time;
  size_t next_earliest = this->wheel_size_;
  ACE_Time_Value next_earliest_time;

  // Find the earliest time
  for (i = 0; i < this->wheel_size_; i++)
    {
      if (this->wheel_[i]->get_next () != this->wheel_[i]
          && this->wheel_[i]->get_next ()->get_timer_value () <= earliest_time)
        {
          earliest = i;
          earliest_time = this->wheel_[i]->get_next ()->get_timer_value ();
        }
    }

  // Check to see if there is nothing to expire
  if (earliest == this->wheel_size_)
    return 0;

  do
    {
      next_earliest_time = cur_time;
      next_earliest = this->wheel_size_;

      // Find 2nd earliest position
      for (i = 0; i < this->wheel_size_; i++)
        {
          if (i != earliest
              && this->wheel_[i]->get_next () != this->wheel_[i]
              && this->wheel_[i]->get_next ()->get_timer_value () <= next_earliest_time)
            {
              next_earliest = i;
              next_earliest_time = this->wheel_[i]->get_next ()->get_timer_value ();
            }
        }

      while (this->wheel_[earliest]->get_next () 
             != this->wheel_[earliest]
             && this->wheel_[earliest]->get_next ()->get_timer_value () 
             <= next_earliest_time)
        {
          // Remove the first node in the earliest position
          ACE_Timer_Node_T<TYPE> *expired =
            this->wheel_[earliest]->get_next ();
          this->wheel_[earliest]->set_next (expired->get_next ());
          expired->get_next ()->set_prev (this->wheel_[earliest]);

          TYPE &type = expired->get_type ();
          const void *act = expired->get_act ();
          int reclaim = 1;

          // Check if this is an interval timer.
          if (expired->get_interval () > ACE_Time_Value::zero)
            {
              // Make sure that we skip past values that have already
              // "expired".
              do
                expired->set_timer_value (expired->get_timer_value () + expired->get_interval ());
              while (expired->get_timer_value () <= cur_time);

              // Since this is an interval timer, we need to
              // reschedule it.
              this->reschedule (expired);
              reclaim = 0;
            }

          // Call the functor.
          this->upcall (type, act, cur_time);

          if (reclaim)
            // Free up the node and the token.
            this->free_node (expired);

          ++number_of_timers_expired;

          // Check to see if we are empty.
          if (this->wheel_[earliest]->get_next () == this->wheel_[earliest])
            break;
        }

      if (next_earliest_time == this->wheel_size_)
        break;

      earliest = next_earliest;
    } while (next_earliest != this->wheel_size_);

  return number_of_timers_expired;
}

#endif /* ACE_TIMER_WHEEL_T_C */
