You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
144 lines
2.6 KiB
144 lines
2.6 KiB
//
|
|
// NearQuery.cc
|
|
//
|
|
// NearQuery: An operator query that filters matches by proximity.
|
|
//
|
|
// Part of the ht://Dig package <http://www.htdig.org/>
|
|
// Copyright (c) 1995-2004 The ht://Dig Group
|
|
// For copyright details, see the file COPYING in your distribution
|
|
// or the GNU Library General Public License (LGPL) version 2 or later
|
|
// <http://www.gnu.org/copyleft/lgpl.html>
|
|
//
|
|
// $Id: NearQuery.cc,v 1.4 2004/05/28 13:15:24 lha Exp $
|
|
//
|
|
|
|
#include "NearQuery.h"
|
|
|
|
String
|
|
NearQuery::OperatorString() const
|
|
{
|
|
String s;
|
|
s << "near/" << distance;
|
|
return s;
|
|
}
|
|
|
|
//
|
|
// l r nextTo
|
|
// -----------------------
|
|
// 0 0 0
|
|
// 0 b 0
|
|
// 0 x 0
|
|
// a 0 0
|
|
// a b near(a, b)
|
|
// a x a
|
|
// x 0 0
|
|
// x b b
|
|
// x x x
|
|
//
|
|
ResultList *
|
|
NearQuery::Evaluate()
|
|
{
|
|
ResultList *result = 0;
|
|
Query *left = (Query *)operands[0];
|
|
Query *right = (Query *)operands[1];
|
|
|
|
if(left && right)
|
|
{
|
|
ResultList *l = left->GetResults();
|
|
if(l)
|
|
{
|
|
ResultList *r = right->GetResults();
|
|
if(r)
|
|
{
|
|
if(l->IsIgnore())
|
|
{
|
|
result = new ResultList(*r);
|
|
}
|
|
else if(r->IsIgnore())
|
|
{
|
|
result = new ResultList(*l);
|
|
}
|
|
else
|
|
{
|
|
result = Near(*l, *r);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return result;
|
|
}
|
|
|
|
ResultList *
|
|
NearQuery::Near(const ResultList &l, const ResultList &r)
|
|
{
|
|
ResultList *result = 0;
|
|
DictionaryCursor c;
|
|
l.Start_Get(c);
|
|
DocMatch *match = (DocMatch *)l.Get_NextElement(c);
|
|
while(match)
|
|
{
|
|
DocMatch *confirm = r.find(match->GetId());
|
|
if(confirm)
|
|
{
|
|
List *locations = MergeLocations(
|
|
*match->GetLocations(),
|
|
*confirm->GetLocations());
|
|
if(locations)
|
|
{
|
|
if(!result)
|
|
{
|
|
result = new ResultList;
|
|
}
|
|
DocMatch *copy = new DocMatch(*match);
|
|
copy->SetLocations(locations);
|
|
result->add(copy);
|
|
}
|
|
}
|
|
match = (DocMatch *)l.Get_NextElement(c);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//
|
|
//: merge match positions in a 'near' operation
|
|
// all combinations are tested; the pairs of positions near enough are kept
|
|
//
|
|
List *
|
|
NearQuery::MergeLocations(const List &p, const List &q)
|
|
{
|
|
List *result = 0;
|
|
ListCursor pc;
|
|
p.Start_Get(pc);
|
|
const Location *left = (const Location *)p.Get_Next(pc);
|
|
while(left)
|
|
{
|
|
ListCursor qc;
|
|
q.Start_Get(qc);
|
|
const Location *right = (const Location *)q.Get_Next(qc);
|
|
while(right)
|
|
{
|
|
int dist = right->from - left->to;
|
|
if(dist < 1)
|
|
{
|
|
dist = left->from - right->to;
|
|
if(dist < 1)
|
|
{
|
|
dist = 0;
|
|
}
|
|
}
|
|
if(unsigned(dist) <= distance)
|
|
{
|
|
if(!result)
|
|
{
|
|
result = new List;
|
|
}
|
|
result->Add(new Location(*left));
|
|
result->Add(new Location(*right));
|
|
}
|
|
right = (const Location *)q.Get_Next(qc);
|
|
}
|
|
left = (const Location *)p.Get_Next(pc);
|
|
}
|
|
return result;
|
|
}
|