__gnu_parallel::_LoserTreeBase< _Tp, _Compare > Class Template Reference

Guarded loser/tournament tree. More...

#include <parallel/losertree.h>

Inheritance diagram for __gnu_parallel::_LoserTreeBase< _Tp, _Compare >:

Classes
struct	_Loser
	Internal representation of a _LoserTree element. More...

Public Member Functions
	_LoserTreeBase (unsigned int __k, _Compare __comp)
	The constructor. More...
	~_LoserTreeBase ()
	The destructor. More...
void	__insert_start (const _Tp &__key, int __source, bool __sup)
	Initializes the sequence "_M_source" with the element "__key". More...
int	__get_min_source ()

Protected Attributes
unsigned int	_M_ik
unsigned int	_M_k
unsigned int	_M_offset
unsigned int	_M_log_k
_Loser *	_M_losers
	_LoserTree __elements. More...
_Compare	_M_comp
	_Compare to use. More...
bool	_M_first_insert
	State flag that determines whether the _LoserTree is empty. More...

Detailed Description

template<typename _Tp, typename _Compare>
class __gnu_parallel::_LoserTreeBase< _Tp, _Compare >

Guarded loser/tournament tree.

The smallest element is at the top.

Guarding is done explicitly through one flag _M_sup per element, inf is not needed due to a better initialization routine. This is a well-performing variant.

Parameters

_Tp	the element type
_Compare	the comparator to use, defaults to std::less<_Tp>

Constructor & Destructor Documentation

template<typename _Tp , typename _Compare >

__gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_LoserTreeBase ( unsigned int  __k, _Compare  __comp  )

inline

The constructor.

Parameters

__k	The number of sequences to merge.
__comp	The comparator to use.

      : _M_comp(__comp)
      {
    _M_ik = __k;

    // Compute log_2{_M_k} for the _Loser Tree
    _M_log_k = __rd_log2(_M_ik - 1) + 1;

    // Next greater power of 2.
    _M_k = 1 << _M_log_k;
    _M_offset = _M_k;

    // Avoid default-constructing _M_losers[]._M_key
    _M_losers = static_cast<_Loser*>(::operator new(2 * _M_k
                            * sizeof(_Loser)));
    for (unsigned int __i = _M_ik - 1; __i < _M_k; ++__i)
      _M_losers[__i + _M_k]._M_sup = true;

    _M_first_insert = true;
      }

template<typename _Tp , typename _Compare >

__gnu_parallel::_LoserTreeBase< _Tp, _Compare >::~_LoserTreeBase ( )

inline

The destructor.

      {
    for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
      _M_losers[__i].~_Loser();
    ::operator delete(_M_losers);
      }

Member Function Documentation

template<typename _Tp , typename _Compare >

int __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::__get_min_source ( )

inline

Returns

the index of the sequence with the smallest element.

      { return _M_losers[0]._M_source; }

template<typename _Tp , typename _Compare >

void __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::__insert_start ( const _Tp &  __key, int  __source, bool  __sup  )

inline

Initializes the sequence "_M_source" with the element "__key".

Parameters

__key	the element to insert
__source	__index of the __source __sequence
__sup	flag that determines whether the value to insert is an explicit __supremum.

      {
    unsigned int __pos = _M_k + __source;

    if (_M_first_insert)
      {
        // Construct all keys, so we can easily destruct them.
        for (unsigned int __i = 0; __i < (2 * _M_k); ++__i)
          ::new(&(_M_losers[__i]._M_key)) _Tp(__key);
        _M_first_insert = false;
      }
    else
      _M_losers[__pos]._M_key = __key;

    _M_losers[__pos]._M_sup = __sup;
    _M_losers[__pos]._M_source = __source;
      }

Member Data Documentation

template<typename _Tp , typename _Compare >

_Compare __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_comp

protected

_Compare to use.

template<typename _Tp , typename _Compare >

bool __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_first_insert

protected

State flag that determines whether the _LoserTree is empty.

Only used for building the _LoserTree.

template<typename _Tp , typename _Compare >

unsigned int __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_ik

protected

template<typename _Tp , typename _Compare >

unsigned int __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_k

protected

template<typename _Tp , typename _Compare >

unsigned int __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_log_k

protected

log_2{_M_k}

template<typename _Tp , typename _Compare >

_Loser* __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_losers

protected

_LoserTree __elements.

template<typename _Tp , typename _Compare >

unsigned int __gnu_parallel::_LoserTreeBase< _Tp, _Compare >::_M_offset

protected

---

The documentation for this class was generated from the following file:

• GCC4/inc/parallel/losertree.h