beagled/Lucene.Net/Search/ExactPhraseScorer.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 using System;
  18 using Lucene.Net.Index;
  19
  20 namespace Lucene.Net.Search
  21 {
  22
  23         sealed class ExactPhraseScorer : PhraseScorer
  24         {
  25
  26                 internal ExactPhraseScorer(Weight weight, TermPositions[] tps, int[] positions, Similarity similarity, byte[] norms) : base(weight, tps, positions, similarity, norms)
  27                 {
  28                 }
  29
  30                 protected internal override float PhraseFreq()
  31                 {
  32                         // sort list with pq
  33                         for (PhrasePositions pp = first; pp != null; pp = pp.next)
  34                         {
  35                                 pp.FirstPosition();
  36                                 pq.Put(pp); // build pq from list
  37                         }
  38                         PqToList(); // rebuild list from pq
  39
  40                         int freq = 0;
  41                         do
  42                         {
  43                                 // find position w/ all terms
  44                                 while (first.position < last.position)
  45                                 {
  46                                         // scan forward in first
  47                                         do
  48                                         {
  49                                                 if (!first.NextPosition())
  50                                                 {
  51                                                         return (float) freq;
  52                                                 }
  53                                         }
  54                                         while (first.position < last.position);
  55                                         FirstToLast();
  56                                 }
  57                                 freq++; // all equal: a match
  58                         }
  59                         while (last.NextPosition());
  60
  61                         return (float) freq;
  62                 }
  63         }
  64 }