AndPostList Class Reference

A postlist comprising two postlists ANDed together. More...

#include <andpostlist.h>

Inheritance diagram for AndPostList:

[legend]Collaboration diagram for AndPostList:


Public Member Functions
Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term.
Xapian::doccount	get_termfreq_min () const
	Get a lower bound on the number of documents indexed by this term.
Xapian::doccount	get_termfreq_est () const
	Get an estimate of the number of documents indexed by this term.
Xapian::docid	get_docid () const
	Return the current docid.
Xapian::weight	get_weight () const
	Return the weight contribution for the current position.
Xapian::weight	get_maxweight () const
	Return an upper bound on what get_weight() can return.
Xapian::weight	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return.
PostList *	next (Xapian::weight w_min)
	Advance the current position to the next document in the postlist.
PostList *	skip_to (Xapian::docid did, Xapian::weight w_min)
	Skip forward to the specified docid.
bool	at_end () const
	Return true if the current position is past the last entry in this list.
std::string	get_description () const
	Return a string description of this object.
virtual Xapian::doclength	get_doclength () const
	Return the document length of the document the current term comes from.
	AndPostList (PostList left, PostList right, MultiMatch *matcher_, Xapian::doccount dbsize_, bool replacement=false)
Protected Attributes
Xapian::docid	head
Xapian::weight	lmax
Xapian::weight	rmax
Private Member Functions
void	process_next_or_skip_to (Xapian::weight w_min, PostList *ret)
Private Attributes
Xapian::doccount	dbsize

Detailed Description

A postlist comprising two postlists ANDed together.

This postlist returns a posting if and only if it is in both of the sub-postlists. The weight for a posting is the sum of the weights of the sub-postings.

Definition at line 36 of file andpostlist.h.

Constructor & Destructor Documentation

AndPostList::AndPostList	(	PostList *	left,
		PostList *	right,
		MultiMatch *	matcher_,
		Xapian::doccount	dbsize_,
		bool	replacement = `false`
	)

Definition at line 80 of file andpostlist.cc.

References DEBUGCALL, Xapian::PostingIterator::Internal::get_maxweight(), Xapian::PostingIterator::Internal::get_termfreq_est(), BranchPostList::l, lmax, BranchPostList::r, and rmax.

Member Function Documentation

void AndPostList::process_next_or_skip_to	(	Xapian::weight	w_min,
		PostList *	ret
	)			`[inline, private]`

Definition at line 31 of file andpostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), DEBUGCALL, DEBUGLINE, Xapian::PostingIterator::Internal::get_docid(), BranchPostList::handle_prune(), head, BranchPostList::l, lmax, BranchPostList::matcher, BranchPostList::r, rmax, and skip_to_handling_prune().

Referenced by next(), and skip_to().

Xapian::doccount AndPostList::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 115 of file andpostlist.cc.

References DEBUGCALL, Xapian::PostingIterator::Internal::get_termfreq_max(), BranchPostList::l, BranchPostList::r, and RETURN.

Xapian::doccount AndPostList::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 122 of file andpostlist.cc.

References dbsize, DEBUGCALL, Xapian::PostingIterator::Internal::get_termfreq_min(), BranchPostList::l, BranchPostList::r, and RETURN.

Xapian::doccount AndPostList::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 141 of file andpostlist.cc.

References dbsize, DEBUGCALL, Xapian::PostingIterator::Internal::get_termfreq_est(), BranchPostList::l, BranchPostList::r, and RETURN.

Xapian::docid AndPostList::get_docid ( ) const [virtual]

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 152 of file andpostlist.cc.

References DEBUGCALL, head, and RETURN.

Xapian::weight AndPostList::get_weight ( ) const [virtual]

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 160 of file andpostlist.cc.

References DEBUGCALL, Xapian::PostingIterator::Internal::get_weight(), BranchPostList::l, BranchPostList::r, and RETURN.

Xapian::weight AndPostList::get_maxweight ( ) const [virtual]

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

Implements Xapian::PostingIterator::Internal.

Definition at line 168 of file andpostlist.cc.

References DEBUGCALL, lmax, RETURN, and rmax.

Referenced by recalc_maxweight().

Xapian::weight AndPostList::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.

Implements Xapian::PostingIterator::Internal.

Definition at line 175 of file andpostlist.cc.

References DEBUGCALL, get_maxweight(), BranchPostList::l, lmax, BranchPostList::r, Xapian::PostingIterator::Internal::recalc_maxweight(), RETURN, and rmax.

PostList * AndPostList::next ( Xapian::weight 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() 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 98 of file andpostlist.cc.

References DEBUGCALL, lmax, Xapian::PostingIterator::Internal::next(), process_next_or_skip_to(), BranchPostList::r, and RETURN.

PostList * AndPostList::skip_to	(	Xapian::docid	,
		Xapian::weight	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 106 of file andpostlist.cc.

References DEBUGCALL, head, lmax, process_next_or_skip_to(), BranchPostList::r, RETURN, and Xapian::PostingIterator::Internal::skip_to().

bool AndPostList::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 184 of file andpostlist.cc.

References DEBUGCALL, head, and RETURN.

std::string AndPostList::get_description ( ) const [virtual]

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 191 of file andpostlist.cc.

References Xapian::PostingIterator::Internal::get_description(), BranchPostList::l, and BranchPostList::r.

Xapian::doclength AndPostList::get_doclength ( ) const [virtual]

Return the document length of the document the current term comes from.

The doclength returned by each branch should be the same. The default implementation is simply to return the result returned by the left branch: the left branch is preferable because this should be the fastest way to get to a leaf node.

Implements Xapian::PostingIterator::Internal.

Definition at line 197 of file andpostlist.cc.

References AssertEqDouble, DEBUGCALL, DEBUGLINE, Xapian::PostingIterator::Internal::get_doclength(), head, BranchPostList::l, BranchPostList::r, and RETURN.