N-way AND postlist. More...

#include <multiandpostlist.h>

Inheritance diagram for MultiAndPostList:

Collaboration diagram for MultiAndPostList:

Classes
struct	ComparePostListTermFreqAscending
	Comparison functor which orders PostList* by ascending get_termfreq_est(). More...

Public Member Functions
template<class RandomItor >
	MultiAndPostList (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...

	MultiAndPostList (PostList l, PostList r, double lmax, double rmax, MultiMatch *matcher_, Xapian::doccount db_size_)
	Construct as the decay product of an OrPostList or AndMaybePostList. More...

	~MultiAndPostList ()

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...

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

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 MultiAndPostlists returns the sum of the wdfs of the sub postlists. More...

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

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

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...

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

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

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

double	new_min (double w_min, size_t n)
	Calculate the new minimum weight for sub-postlist n. More...

void	next_helper (size_t n, double w_min)
	Call next on a sub-postlist n, and handle any pruning. More...

void	skip_to_helper (size_t n, Xapian::docid did_min, double w_min)
	Call skip_to on a sub-postlist n, and handle any pruning. More...

void	check_helper (size_t n, Xapian::docid did_min, double w_min, bool &valid)
	Call check on a sub-postlist n, and handle any pruning. More...

void	allocate_plist_and_max_wt ()
	Allocate plist and max_wt arrays of n_kids each. More...

PostList *	find_next_match (double w_min)
	Advance the sublists to the next match. 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_wt
	Array of maximum weights for the sub-postlists. More...

double	max_total
	Total maximum weight (== sum of max_wt values). 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 AND postlist.

Definition at line 32 of file multiandpostlist.h.

Constructor & Destructor Documentation

◆ MultiAndPostList() [1/3]

MultiAndPostList::MultiAndPostList ( const MultiAndPostList & )

private

Don't allow copying.

Referenced by MultiAndPostList::ComparePostListTermFreqAscending::operator()().

◆ MultiAndPostList() [2/3]

template<class RandomItor >

MultiAndPostList::MultiAndPostList	(	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 122 of file multiandpostlist.h.

References allocate_plist_and_max_wt().

◆ MultiAndPostList() [3/3]

MultiAndPostList::MultiAndPostList	(	PostList *	l,
		PostList *	r,
		double	lmax,
		double	rmax,
		MultiMatch *	matcher_,
		Xapian::doccount	db_size_
	)

inline

Construct as the decay product of an OrPostList or AndMaybePostList.

Definition at line 137 of file multiandpostlist.h.

References allocate_plist_and_max_wt(), at_end(), count_matching_subqs(), gather_position_lists(), get_description(), get_docid(), get_doclength(), get_maxweight(), Xapian::PostingIterator::Internal::get_termfreq_est(), get_termfreq_est(), get_termfreq_est_using_stats(), get_termfreq_max(), get_termfreq_min(), get_unique_terms(), get_wdf(), get_weight(), Xapian::PostingIterator::Internal::next(), recalc_maxweight(), skip_to(), and ~MultiAndPostList().

◆ ~MultiAndPostList()

MultiAndPostList::~MultiAndPostList ( )

Definition at line 43 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

Member Function Documentation

◆ allocate_plist_and_max_wt()

void MultiAndPostList::allocate_plist_and_max_wt ( )

private

Allocate plist and max_wt arrays of n_kids each.

Exceptions

std::bad_alloc.

Definition at line 31 of file multiandpostlist.cc.

Referenced by check_helper(), and MultiAndPostList().

◆ at_end()

bool MultiAndPostList::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 191 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ check_helper()

void MultiAndPostList::check_helper	(	size_t	n,
		Xapian::docid	did_min,
		double	w_min,
		bool &	valid
	)

inlineprivate

Call check on a sub-postlist n, and handle any pruning.

Definition at line 97 of file multiandpostlist.h.

References allocate_plist_and_max_wt(), Xapian::PostingIterator::Internal::check(), find_next_match(), new_min(), and MultiMatch::recalc_maxweight().

◆ count_matching_subqs()

Xapian::termcount MultiAndPostList::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 275 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ find_next_match()

PostList * MultiAndPostList::find_next_match ( double w_min )

private

Advance the sublists to the next match.

Definition at line 209 of file multiandpostlist.cc.

References Xapian::PostingIterator::Internal::get_docid().

Referenced by check_helper().

◆ gather_position_lists()

void MultiAndPostList::gather_position_lists ( OrPositionList * orposlist )

virtual

Gather PositionList* objects for a subtree.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 285 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_description()

std::string MultiAndPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 252 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_docid()

Xapian::docid MultiAndPostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 152 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_doclength()

Xapian::termcount MultiAndPostList::get_doclength ( ) const

virtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 158 of file multiandpostlist.cc.

References Assert, and AssertEq.

Referenced by MultiAndPostList().

◆ get_maxweight()

double MultiAndPostList::get_maxweight ( ) const

virtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 146 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_termfreq_est()

Xapian::doccount MultiAndPostList::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 92 of file multiandpostlist.cc.

References Assert, and LOGCALL.

Referenced by get_termfreq_min(), and MultiAndPostList().

◆ get_termfreq_est_using_stats()

TermFreqs MultiAndPostList::get_termfreq_est_using_stats ( const Xapian::Weight::Internal & stats ) const

virtual

Get an estimate for the termfreq and reltermfreq, given the stats.

The frequencies may be for a combination of databases, or for just the relevant documents, so the results need not lie in the bounds given by get_termfreq_min() and get_termfreq_max().

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 108 of file multiandpostlist.cc.

References Assert, Xapian::Weight::Internal::collection_size, TermFreqs::collfreq, if(), LOGCALL, TermFreqs::reltermfreq, RETURN, Xapian::Weight::Internal::rset_size, TermFreqs::termfreq, Xapian::Weight::Internal::total_length, and usual.

Referenced by MultiAndPostList().

◆ get_termfreq_max()

Xapian::doccount MultiAndPostList::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 80 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_termfreq_min()

Xapian::doccount MultiAndPostList::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 55 of file multiandpostlist.cc.

References AssertRelParanoid, and get_termfreq_est().

Referenced by MultiAndPostList().

◆ get_unique_terms()

Xapian::termcount MultiAndPostList::get_unique_terms ( ) const

virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 169 of file multiandpostlist.cc.

References Assert, and AssertEq.

Referenced by MultiAndPostList().

◆ get_wdf()

Xapian::termcount MultiAndPostList::get_wdf ( ) const

virtual

get_wdf() for MultiAndPostlists returns the sum of the wdfs of the sub postlists.

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 265 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ get_weight()

double MultiAndPostList::get_weight ( ) const

virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 180 of file multiandpostlist.cc.

References Assert.

Referenced by MultiAndPostList().

◆ new_min()

double MultiAndPostList::new_min	(	double	w_min,
		size_t	n
	)

inlineprivate

Calculate the new minimum weight for sub-postlist n.

Definition at line 70 of file multiandpostlist.h.

Referenced by check_helper(), next_helper(), and skip_to_helper().

◆ next()

PostList * MultiAndPostList::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 238 of file multiandpostlist.cc.

◆ next_helper()

void MultiAndPostList::next_helper	(	size_t	n,
		double	w_min
	)

inlineprivate

Call next on a sub-postlist n, and handle any pruning.

Definition at line 75 of file multiandpostlist.h.

References new_min(), Xapian::PostingIterator::Internal::next(), and MultiMatch::recalc_maxweight().

◆ operator=()

void MultiAndPostList::operator= ( const MultiAndPostList & )

private

Don't allow assignment.

Referenced by MultiAndPostList::ComparePostListTermFreqAscending::operator()().

◆ recalc_maxweight()

double MultiAndPostList::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 197 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ skip_to()

PostList * MultiAndPostList::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 245 of file multiandpostlist.cc.

Referenced by MultiAndPostList().

◆ skip_to_helper()

void MultiAndPostList::skip_to_helper	(	size_t	n,
		Xapian::docid	did_min,
		double	w_min
	)

inlineprivate

Call skip_to on a sub-postlist n, and handle any pruning.

Definition at line 86 of file multiandpostlist.h.

References new_min(), MultiMatch::recalc_maxweight(), and Xapian::PostingIterator::Internal::skip_to().

Member Data Documentation

◆ db_size

Xapian::doccount MultiAndPostList::db_size

private

The number of documents in the database.

Definition at line 64 of file multiandpostlist.h.

◆ did

Xapian::docid MultiAndPostList::did

private

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

Definition at line 49 of file multiandpostlist.h.

◆ matcher

MultiMatch* MultiAndPostList::matcher

private

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

Definition at line 67 of file multiandpostlist.h.

◆ max_total

double MultiAndPostList::max_total

private

Total maximum weight (== sum of max_wt values).

Definition at line 61 of file multiandpostlist.h.

◆ max_wt

double* MultiAndPostList::max_wt

private

Array of maximum weights for the sub-postlists.

Definition at line 58 of file multiandpostlist.h.

◆ n_kids

size_t MultiAndPostList::n_kids

private

The number of sub-postlists.

Definition at line 52 of file multiandpostlist.h.

◆ plist

PostList** MultiAndPostList::plist

private

Array of pointers to sub-postlists.

Definition at line 55 of file multiandpostlist.h.

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

matcher/multiandpostlist.h
matcher/multiandpostlist.cc

Classes

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MultiAndPostList() [1/3]

◆ MultiAndPostList() [2/3]

◆ MultiAndPostList() [3/3]

◆ ~MultiAndPostList()

Member Function Documentation

◆ allocate_plist_and_max_wt()

◆ at_end()

◆ check_helper()

◆ count_matching_subqs()

◆ find_next_match()

◆ gather_position_lists()

◆ get_description()

◆ get_docid()

◆ get_doclength()

◆ get_maxweight()

◆ get_termfreq_est()

◆ get_termfreq_est_using_stats()

◆ get_termfreq_max()

◆ get_termfreq_min()

◆ get_unique_terms()

◆ get_wdf()

◆ get_weight()

◆ new_min()

◆ next()

◆ next_helper()

◆ operator=()

◆ recalc_maxweight()

◆ skip_to()

◆ skip_to_helper()

Member Data Documentation

◆ db_size

◆ did

◆ matcher

◆ max_total

◆ max_wt

◆ n_kids

◆ plist