87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
/* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; version 2 of the License.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
|
|
|
|
|
|
#ifndef BOUNDED_HEAP_STD_INCLUDED
|
|
#define BOUNDED_HEAP_STD_INCLUDED
|
|
|
|
#include "my_global.h"
|
|
#include "my_base.h"
|
|
#include <vector>
|
|
#include <queue>
|
|
|
|
template<typename Element_type,
|
|
typename Key_type,
|
|
typename Key_generator,
|
|
typename Key_compare = std::less<Key_type>
|
|
>
|
|
class Bounded_queue_std
|
|
{
|
|
public:
|
|
Bounded_queue_std()
|
|
: m_cmp(),
|
|
m_sort_keys(NULL),
|
|
m_compare_length(0),
|
|
m_sort_param(NULL),
|
|
m_max_elements(0),
|
|
m_num_elements(0)
|
|
{}
|
|
|
|
int init(ha_rows max_elements,
|
|
Key_generator *sort_param,
|
|
Key_type *sort_keys)
|
|
{
|
|
m_sort_keys= sort_keys;
|
|
m_compare_length= sort_param->compare_length();
|
|
m_sort_param= sort_param;
|
|
m_max_elements= max_elements + 1;
|
|
return 0;
|
|
}
|
|
|
|
void push(Element_type element)
|
|
{
|
|
if (m_num_elements == m_max_elements)
|
|
{
|
|
m_queue.pop();
|
|
--m_num_elements;
|
|
}
|
|
{
|
|
m_sort_param->make_sortkey(m_sort_keys[m_queue.size()], element);
|
|
m_queue.push(m_sort_keys[m_queue.size()]);
|
|
++m_num_elements;
|
|
}
|
|
}
|
|
|
|
size_t num_elements() const { return m_num_elements; }
|
|
|
|
typedef std::priority_queue<Key_type,
|
|
std::vector<Key_type>,
|
|
Key_compare> Queue_type;
|
|
|
|
private:
|
|
Queue_type m_queue;
|
|
Key_compare m_cmp;
|
|
Key_type *m_sort_keys;
|
|
size_t m_compare_length;
|
|
Key_generator *m_sort_param;
|
|
size_t m_max_elements;
|
|
size_t m_num_elements;
|
|
};
|
|
|
|
|
|
|
|
|
|
#endif // BOUNDED_HEAP_STD_INCLUDED
|