/*
//@HEADER
// ************************************************************************
// 
//                        Kokkos v. 2.0
//              Copyright (2014) Sandia Corporation
// 
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact  H. Carter Edwards (hcedwar@sandia.gov)
// 
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//@HEADER
*/

#include <Kokkos_Core.hpp>

#if defined( KOKKOS_HAVE_SERIAL ) && defined( KOKKOS_ENABLE_TASKPOLICY )

#include <impl/Kokkos_TaskQueue_impl.hpp>

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

namespace Kokkos {
namespace Impl {

template class TaskQueue< Kokkos::Serial > ;

void TaskQueueSpecialization< Kokkos::Serial >::execute
  ( TaskQueue< Kokkos::Serial > * const queue )
{
  using execution_space = Kokkos::Serial ;
  using queue_type      = TaskQueue< execution_space > ;
  using task_root_type  = TaskBase< execution_space , void , void > ;
  using Member          = TaskExec< execution_space > ;

  task_root_type * const end = (task_root_type *) task_root_type::EndTag ;

  Member exec ;

  // Loop until all queues are empty
  while ( 0 < queue->m_ready_count ) {

    task_root_type * task = end ;

    for ( int i = 0 ; i < queue_type::NumQueue && end == task ; ++i ) {
      for ( int j = 0 ; j < 2 && end == task ; ++j ) {
        task = queue_type::pop_task( & queue->m_ready[i][j] );
      }
    }

    if ( end != task ) {

      // pop_task resulted in lock == task->m_next
      // In the executing state

      (*task->m_apply)( task , & exec );

#if 0
  printf( "TaskQueue<Serial>::executed: 0x%lx { 0x%lx 0x%lx %d %d %d }\n"
        , uintptr_t(task)
        , uintptr_t(task->m_wait)
        , uintptr_t(task->m_next)
        , task->m_task_type
        , task->m_priority
        , task->m_ref_count );
#endif

      // If a respawn then re-enqueue otherwise the task is complete
      // and all tasks waiting on this task are updated.
      queue->complete( task );
    }
    else if ( 0 != queue->m_ready_count ) {
      Kokkos::abort("TaskQueue<Serial>::execute ERROR: ready_count");
    }
  }
}

void TaskQueueSpecialization< Kokkos::Serial > ::
  iff_single_thread_recursive_execute(
    TaskQueue< Kokkos::Serial > * const queue )
{
  using execution_space = Kokkos::Serial ;
  using queue_type      = TaskQueue< execution_space > ;
  using task_root_type  = TaskBase< execution_space , void , void > ;
  using Member          = TaskExec< execution_space > ;

  task_root_type * const end = (task_root_type *) task_root_type::EndTag ;

  Member exec ;

  // Loop until no runnable task

  task_root_type * task = end ;
  
  do {

    task = end ;

    for ( int i = 0 ; i < queue_type::NumQueue && end == task ; ++i ) {
      for ( int j = 0 ; j < 2 && end == task ; ++j ) {
        task = queue_type::pop_task( & queue->m_ready[i][j] );
      }
    }

    if ( end == task ) break ;

    (*task->m_apply)( task , & exec );

    queue->complete( task );

  } while(1);
}

}} /* namespace Kokkos::Impl */

#endif /* #if defined( KOKKOS_HAVE_SERIAL ) && defined( KOKKOS_ENABLE_TASKPOLICY ) */

