beagled/Lucene.Net/Index/SegmentTermPositions.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 using System;
  17 using InputStream = Lucene.Net.Store.InputStream;
  18 namespace Lucene.Net.Index
  19 {
  20
  21         sealed class SegmentTermPositions : SegmentTermDocs, TermPositions
  22         {
  23                 private InputStream proxStream;
  24                 private int proxCount;
  25                 private int position;
  26
  27                 internal SegmentTermPositions(SegmentReader p):base(p)
  28                 {
  29                         this.proxStream = (InputStream) parent.proxStream.Clone();
  30                 }
  31
  32                 internal override void  Seek(TermInfo ti)
  33                 {
  34                         base.Seek(ti);
  35                         if (ti != null)
  36                                 proxStream.Seek(ti.proxPointer);
  37                         proxCount = 0;
  38                 }
  39
  40                 public override void  Close()
  41                 {
  42                         base.Close();
  43                         proxStream.Close();
  44                 }
  45
  46                 public int NextPosition()
  47                 {
  48                         proxCount--;
  49                         return position += proxStream.ReadVInt();
  50                 }
  51
  52                 protected internal override void  SkippingDoc()
  53                 {
  54                         for (int f = freq; f > 0; f--)
  55                         // skip all positions
  56                                 proxStream.ReadVInt();
  57                 }
  58
  59                 public override bool Next()
  60                 {
  61                         for (int f = proxCount; f > 0; f--)
  62                         // skip unread positions
  63                                 proxStream.ReadVInt();
  64
  65                         if (base.Next())
  66                         {
  67                                 // run super
  68                                 proxCount = freq; // note frequency
  69                                 position = 0; // reset position
  70                                 return true;
  71                         }
  72                         return false;
  73                 }
  74
  75                 public override int Read(int[] docs, int[] freqs)
  76                 {
  77                         throw new System.NotSupportedException("TermPositions does not support processing multiple documents in one call. Use TermDocs instead.");
  78                 }
  79
  80
  81                 /// <summary>Called by base.SkipTo(). </summary>
  82                 protected internal override void  SkipProx(long proxPointer)
  83                 {
  84                         proxStream.Seek(proxPointer);
  85                         proxCount = 0;
  86                 }
  87         }
  88 }