1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
//
// AndQuery.cc
//
// AndQuery: an operator query that does 'and' combination
//
// Part of the ht://Dig package <https://htdig.sourceforge.net/>
// 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: AndQuery.cc,v 1.4 2004/05/28 13:15:24 lha Exp $
//
#include "AndQuery.h"
//
// l r and
// ----------------------
// 0 0 0
// 0 b 0
// 0 x 0
// a 0 0
// a b intersect(a,b)
// a x a
// x 0 0
// x b b
// x x x
//
// i.e. some 0 => 0
// ignores can be left out of intersection
// the shorter of the result lists is put apart for intersection
// this optimises the intersection process
//
ResultList *
AndQuery::Evaluate()
{
ResultList *result = 0;
ResultList *shorter = 0;
operands.Start_Get();
Query *operand = (Query *) operands.Get_Next();
while(operand && !shorter)
{
result = operand->GetResults();
if(!result)
{
break;
}
if(!result->IsIgnore())
{
shorter = result;
}
operand = (Query *) operands.Get_Next();
}
if(shorter)
{
List longer;
while(operand && result)
{
result = operand->GetResults();
if(result && !result->IsIgnore())
{
if(result->Count() < shorter->Count())
{
longer.Add(shorter);
shorter = result;
}
else
{
longer.Add(result);
}
}
operand = (Query *) operands.Get_Next();
}
if(longer.Count())
{
result = Intersection(*shorter, longer);
longer.Release();
}
else
{
result = new ResultList(*shorter);
}
}
return result;
}
//
// return a result list containing only the matches common to
// all input parameters.
//
// l is iterated, matches from l are searched in all elements of rs
//
//
// foreach match in shorter
// confirm the match in each lists
// if confirmed
// copy all matches in result
//
// the shorter of the input lists is assumed to be in the first parameter
// this is a modest optimisation in order to minimise iteration
//
ResultList *
AndQuery::Intersection(const ResultList &shorter, const List &lists)
{
ResultList *result = 0;
DictionaryCursor c;
shorter.Start_Get(c);
DocMatch *match = (DocMatch *)shorter.Get_NextElement(c);
while(match)
{
List confirms;
ListCursor lc;
lists.Start_Get(lc);
ResultList *list = (ResultList *)lists.Get_Next(lc);
while(list)
{
DocMatch *confirm = list->find(match->GetId());
if(confirm)
{
confirms.Add(confirm);
}
list = (ResultList *)lists.Get_Next(lc);
}
if(confirms.Count() == lists.Count())
{
if(!result)
{
result = new ResultList;
}
DocMatch *copy = new DocMatch(*match);
confirms.Start_Get();
DocMatch *confirm = (DocMatch *)confirms.Get_Next();
while(confirm)
{
copy->Merge(*confirm);
confirm = (DocMatch *)confirms.Get_Next();
}
result->add(copy);
}
confirms.Release();
match = (DocMatch *)shorter.Get_NextElement(c);
}
return result;
}
|
