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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/util/locked/pqueue.H $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* COPYRIGHT International Business Machines Corp. 2010,2014 */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __UTIL_LOCKED_PQUEUE_H
#define __UTIL_LOCKED_PQUEUE_H
#include <util/locked/queue.H>
namespace Util
{
namespace Locked
{
template <typename _T, typename _K,
bool locked = false, typename _S = int>
class PQueue : public Queue<_T, locked, _S>
{
public:
void insert(_T*);
_T* remove_if(_K&);
_T* front();
private:
void bubbleUp(_T*);
};
// SFINAE template to ensure compile fails if functions which are not
// SMP-safe are used on a 'locked' instance.
template<bool locked>
class __verify_pqueue_is_smp_safe
{
public:
__verify_pqueue_is_smp_safe()
{
class __util_locked_pqueue_is_not_smp_safe;
__util_locked_pqueue_is_not_smp_safe();
}
};
// SFINAE template implementation to allow certain functions when the
// instance is not 'locked', assuming that caller is ensuring safety
// in some other way.
template<>
class __verify_pqueue_is_smp_safe<false>
{
public:
__verify_pqueue_is_smp_safe()
{
}
};
template <typename _T, typename _K, bool locked, typename _S>
void PQueue<_T,_K,locked,_S>::insert(_T* item)
{
this->__lock();
if (this->head == NULL)
{
item->next = item->prev = NULL;
this->head = this->tail = item;
}
else
{
item->prev = NULL;
item->next = this->head;
this->head = this->head->prev = item;
bubbleUp(item);
}
this->__unlock();
}
template <typename _T, typename _K, bool locked, typename _S>
_T* PQueue<_T,_K,locked,_S>::remove_if(_K& key)
{
_T* item = NULL;
this->__lock();
if ((this->tail != NULL) && (this->tail->key <= key))
{
item = this->tail;
if (this->head == this->tail)
this->head = this->tail = NULL;
else
this->tail = item->prev;
if (item->prev)
item->prev->next = NULL;
}
this->__unlock();
return item;
}
template <typename _T, typename _K, bool locked, typename _S>
void PQueue<_T,_K,locked,_S>::bubbleUp(_T* item)
{
while(1)
{
if (!item->next)
break;
if (item->next->key <= item->key)
break;
if (this->head == item)
this->head = item->next;
if (this->tail == item->next)
this->tail = item;
_T* temp = item->next;
if (temp->next)
{
temp->next->prev = item;
item->next = item->next->next;
}
else
{
item->next = NULL;
}
if (item->prev)
{
item->prev->next = temp;
temp->prev = item->prev;
}
else
{
temp->prev = NULL;
}
temp->next = item;
item->prev = temp;
}
}
template <typename _T, typename _K, bool locked, typename _S>
_T* PQueue<_T, _K,locked,_S>::front()
{
// Entirely not SMP-safe to return a pointer to a node if
// we are a locking instance. If we aren't locking we
// have to assume that the caller is ensuring SMP-safety
// globally in some other way. Use SFINAE technique to
// ensure front() fails on locked lists.
__verify_pqueue_is_smp_safe<locked>();
return this->tail;
}
};
};
#endif
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