本文整理汇总了C++中CBitSet::Equals方法的典型用法代码示例。如果您正苦于以下问题：C++ CBitSet::Equals方法的具体用法？C++ CBitSet::Equals怎么用？C++ CBitSet::Equals使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类CBitSet的用法示例。
在下文中一共展示了CBitSet::Equals方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: PexprCross
//---------------------------------------------------------------------------
// @function:
// CJoinOrderDP::PexprBestJoinOrder
//
// @doc:
// find best join order for a given set of elements;
//
//---------------------------------------------------------------------------
CExpression *
CJoinOrderDP::PexprBestJoinOrder
(
CBitSet *pbs
)
{
GPOS_CHECK_STACK_SIZE;
GPOS_CHECK_ABORT;
GPOS_ASSERT(NULL != pbs);
// start by looking-up cost in the DP map
CExpression *pexpr = PexprLookup(pbs);
if (pexpr == m_pexprDummy)
{
// no join order could be created
return NULL;
}
if (NULL != pexpr)
{
// join order is found by looking up map
return pexpr;
}
// find maximal covered subset
CBitSet *pbsCovered = PbsCovered(pbs);
if (0 == pbsCovered->Size())
{
// set is not covered, return a cross product
pbsCovered->Release();
return PexprCross(pbs);
}
if (!pbsCovered->Equals(pbs))
{
// create a cross product for uncovered subset
CBitSet *pbsUncovered = GPOS_NEW(m_mp) CBitSet(m_mp, *pbs);
pbsUncovered->Difference(pbsCovered);
CExpression *pexprResult =
PexprJoinCoveredSubsetWithUncoveredSubset(pbs, pbsCovered, pbsUncovered);
pbsCovered->Release();
pbsUncovered->Release();
return pexprResult;
}
pbsCovered->Release();
// if set has size 2, there is only one possible solution
if (2 == pbs->Size())
{
return PexprJoin(pbs);
}
// otherwise, compute best join order using dynamic programming
CExpression *pexprBestJoinOrder = PexprBestJoinOrderDP(pbs);
if (pexprBestJoinOrder == m_pexprDummy)
{
// no join order could be created
return NULL;
}
return pexprBestJoinOrder;
}