N-way OR postlist with wt=max(wt_i). More...

#include <maxpostlist.h>

Inheritance diagram for MaxPostList:

Collaboration diagram for MaxPostList:

Public Member Functions
template<class RandomItor >
	MaxPostList (RandomItor pl_begin, RandomItor pl_end, MultiMatch *matcher_, Xapian::doccount db_size_)
	Construct from 2 random-access iterators to a container of PostList*, a pointer to the matcher, and the document collection size. More...

	~MaxPostList ()

Xapian::doccount	get_termfreq_min () const
	Get a lower bound on the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_est () const
	Get an estimate of the number of documents indexed by this term. More...

double	get_maxweight () const
	Return an upper bound on what get_weight() can return. More...

Xapian::docid	get_docid () const
	Return the current docid. More...

Xapian::termcount	get_doclength () const
	Return the length of current document. More...

Xapian::termcount	get_unique_terms () const
	Return the number of unique terms in the current document. More...

double	get_weight () const
	Return the weight contribution for the current position. More...

bool	at_end () const
	Return true if the current position is past the last entry in this list. More...

double	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return. More...

PositionList *	read_position_list ()
	Read the position list for the term in the current document and return a pointer to it (owned by the PostList). More...

PostList *	next (double w_min)
	Advance the current position to the next document in the postlist. More...

PostList *	skip_to (Xapian::docid, double w_min)
	Skip forward to the specified docid. More...

std::string	get_description () const
	Return a string description of this object. More...

Xapian::termcount	get_wdf () const
	get_wdf() for MaxPostlist returns the sum of the wdfs of the sub postlists which match the current docid. More...

Xapian::termcount	count_matching_subqs () const
	Count the number of leaf subqueries which match at the current position. More...

Public Member Functions inherited from Xapian::PostingIterator::Internal
virtual	~Internal ()
	We have virtual methods and want to be able to delete derived classes using a pointer to the base class, so we need a virtual destructor. More...

virtual TermFreqs	get_termfreq_est_using_stats (const Xapian::Weight::Internal &stats) const
	Get an estimate for the termfreq and reltermfreq, given the stats. More...

virtual const std::string *	get_sort_key () const

virtual const std::string *	get_collapse_key () const
	If the collapse key is already known, return it. More...

virtual PositionList *	open_position_list () const
	Read the position list for the term in the current document and return a pointer to it (not owned by the PostList). More...

virtual Internal *	check (Xapian::docid did, double w_min, bool &valid)
	Check if the specified docid occurs in this postlist. More...

Internal *	next ()
	Advance the current position to the next document in the postlist. More...

Internal *	skip_to (Xapian::docid did)
	Skip forward to the specified docid. More...

virtual void	gather_position_lists (OrPositionList *orposlist)
	Gather PositionList* objects for a subtree. More...

Public Member Functions inherited from Xapian::Internal::intrusive_base
	intrusive_base ()
	Construct with no references. More...

Private Member Functions
void	operator= (const MaxPostList &)
	Don't allow assignment. More...

	MaxPostList (const MaxPostList &)
	Don't allow copying. More...

void	erase_sublist (size_t i)
	Erase a sub-postlist. More...

Private Attributes
Xapian::docid	did
	The current docid, or zero if we haven't started or are at_end. More...

size_t	n_kids
	The number of sub-postlists. More...

PostList **	plist
	Array of pointers to sub-postlists. More...

double	max_cached
	Cached answer to get_maxweight. More...

Xapian::doccount	db_size
	The number of documents in the database. More...

MultiMatch *	matcher
	Pointer to the matcher object, so we can report pruning. More...

Additional Inherited Members
Public Attributes inherited from Xapian::Internal::intrusive_base
unsigned	_refs
	Reference count. More...

Protected Member Functions inherited from Xapian::PostingIterator::Internal
	Internal ()
	Only constructable as a base class for derived classes. More...

Detailed Description

N-way OR postlist with wt=max(wt_i).

Definition at line 32 of file maxpostlist.h.

Constructor & Destructor Documentation

◆ MaxPostList() [1/2]

MaxPostList::MaxPostList ( const MaxPostList & )

private

Don't allow copying.

◆ MaxPostList() [2/2]

template<class RandomItor >

MaxPostList::MaxPostList	(	RandomItor	pl_begin,
		RandomItor	pl_end,
		MultiMatch *	matcher_,
		Xapian::doccount	db_size_
	)

inline

Construct from 2 random-access iterators to a container of PostList*, a pointer to the matcher, and the document collection size.

Definition at line 72 of file maxpostlist.h.

References at_end(), get_docid(), get_doclength(), get_maxweight(), get_termfreq_est(), get_termfreq_max(), get_termfreq_min(), get_unique_terms(), get_weight(), n_kids, recalc_maxweight(), and ~MaxPostList().

◆ ~MaxPostList()

MaxPostList::~MaxPostList ( )

Definition at line 31 of file maxpostlist.cc.

Referenced by MaxPostList().

Member Function Documentation

◆ at_end()

bool MaxPostList::at_end ( ) const

virtual

Return true if the current position is past the last entry in this list.

Implements Xapian::PostingIterator::Internal.

Definition at line 147 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ count_matching_subqs()

Xapian::termcount MaxPostList::count_matching_subqs ( ) const

virtual

Count the number of leaf subqueries which match at the current position.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 272 of file maxpostlist.cc.

Referenced by read_position_list().

◆ erase_sublist()

void MaxPostList::erase_sublist ( size_t i )

inlineprivate

Erase a sub-postlist.

Definition at line 58 of file maxpostlist.h.

References n_kids, and MultiMatch::recalc_maxweight().

◆ get_description()

string MaxPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 248 of file maxpostlist.cc.

Referenced by read_position_list().

◆ get_docid()

Xapian::docid MaxPostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 89 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ get_doclength()

Xapian::termcount MaxPostList::get_doclength ( ) const

virtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 95 of file maxpostlist.cc.

References Assert, and AssertEq.

Referenced by MaxPostList().

◆ get_maxweight()

double MaxPostList::get_maxweight ( ) const

virtual

Return an upper bound on what get_weight() can return.

Implements Xapian::PostingIterator::Internal.

Definition at line 83 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ get_termfreq_est()

Xapian::doccount MaxPostList::get_termfreq_est ( ) const

virtual

Get an estimate of the number of documents indexed by this term.

It should always be true that: get_termfreq_min() <= get_termfreq_est() <= get_termfreq_max()

Implements Xapian::PostingIterator::Internal.

Definition at line 65 of file maxpostlist.cc.

References Assert.

Referenced by MaxPostList().

◆ get_termfreq_max()

Xapian::doccount MaxPostList::get_termfreq_max ( ) const

virtual

Get an upper bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 52 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ get_termfreq_min()

Xapian::doccount MaxPostList::get_termfreq_min ( ) const

virtual

Get a lower bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 42 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ get_unique_terms()

Xapian::termcount MaxPostList::get_unique_terms ( ) const

virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 115 of file maxpostlist.cc.

References Assert, and AssertEq.

Referenced by MaxPostList().

◆ get_wdf()

Xapian::termcount MaxPostList::get_wdf ( ) const

virtual

get_wdf() for MaxPostlist returns the sum of the wdfs of the sub postlists which match the current docid.

The wdf isn't really meaningful in many situations, but if the lists are being combined as a synonym we want the sum of the wdfs, so we do that in general.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 261 of file maxpostlist.cc.

Referenced by read_position_list().

◆ get_weight()

double MaxPostList::get_weight ( ) const

virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 135 of file maxpostlist.cc.

References Assert.

Referenced by MaxPostList().

◆ next()

PostList * MaxPostList::next ( double w_min )

virtual

Advance the current position to the next document in the postlist.

The list starts before the first entry in the list, so next(), skip_to() or check() must be called before any methods which need the context of the current position.

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 163 of file maxpostlist.cc.

References Xapian::PostingIterator::Internal::get_docid(), Xapian::PostingIterator::Internal::next(), and Xapian::PostingIterator::Internal::skip_to().

◆ operator=()

void MaxPostList::operator= ( const MaxPostList & )

private

Don't allow assignment.

◆ read_position_list()

PositionList* MaxPostList::read_position_list ( )

inlinevirtual

Read the position list for the term in the current document and return a pointer to it (owned by the PostList).

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 103 of file maxpostlist.h.

References count_matching_subqs(), get_description(), get_wdf(), Xapian::PostingIterator::Internal::next(), and skip_to().

◆ recalc_maxweight()

double MaxPostList::recalc_maxweight ( )

virtual

Recalculate the upper bound on what get_weight() can return.

If the tree has pruned, get_maxweight() may use cached values. Calling this method instead forces a full recalculation.

Note that this method may be called after the postlist has reached the end. In this situation, the method should return 0.

Implements Xapian::PostingIterator::Internal.

Definition at line 153 of file maxpostlist.cc.

Referenced by MaxPostList().

◆ skip_to()

PostList * MaxPostList::skip_to	(	Xapian::docid	did,
		double	w_min
	)

virtual

Skip forward to the specified docid.

If the specified docid isn't in the list, position ourselves on the first document after it (or at_end() if no greater docids are present).

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 208 of file maxpostlist.cc.

References Xapian::PostingIterator::Internal::get_docid(), and Xapian::PostingIterator::Internal::skip_to().

Referenced by read_position_list().

Member Data Documentation

◆ db_size

Xapian::doccount MaxPostList::db_size

private

The number of documents in the database.

Definition at line 52 of file maxpostlist.h.

◆ did

Xapian::docid MaxPostList::did

private

The current docid, or zero if we haven't started or are at_end.

Definition at line 40 of file maxpostlist.h.

◆ matcher

MultiMatch* MaxPostList::matcher

private

Pointer to the matcher object, so we can report pruning.

Definition at line 55 of file maxpostlist.h.

◆ max_cached

double MaxPostList::max_cached

private

Cached answer to get_maxweight.

Definition at line 49 of file maxpostlist.h.

◆ n_kids

size_t MaxPostList::n_kids

private

The number of sub-postlists.

Definition at line 43 of file maxpostlist.h.

Referenced by erase_sublist(), and MaxPostList().

◆ plist

PostList** MaxPostList::plist

private

Array of pointers to sub-postlists.

Definition at line 46 of file maxpostlist.h.

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

matcher/maxpostlist.h
matcher/maxpostlist.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MaxPostList() [1/2]

◆ MaxPostList() [2/2]

◆ ~MaxPostList()

Member Function Documentation

◆ at_end()

◆ count_matching_subqs()

◆ erase_sublist()

◆ get_description()

◆ get_docid()

◆ get_doclength()

◆ get_maxweight()

◆ get_termfreq_est()

◆ get_termfreq_max()

◆ get_termfreq_min()

◆ get_unique_terms()

◆ get_wdf()

◆ get_weight()

◆ next()

◆ operator=()

◆ read_position_list()

◆ recalc_maxweight()

◆ skip_to()

Member Data Documentation

◆ db_size

◆ did

◆ matcher

◆ max_cached

◆ n_kids

◆ plist