Lucene.Net  3.0.3
Lucene.Net is a .NET port of the Java Lucene Indexing Library
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TermBuffer.cs
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2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
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9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
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14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 using System;
19 using Lucene.Net.Support;
20 using IndexInput = Lucene.Net.Store.IndexInput;
21 using UnicodeUtil = Lucene.Net.Util.UnicodeUtil;
22 
23 namespace Lucene.Net.Index
24 {
25 
26  sealed class TermBuffer : System.ICloneable
27  {
28 
29  private System.String field;
30  private Term term; // cached
31  private bool preUTF8Strings; // true if strings are stored in modified UTF8 encoding (LUCENE-510)
32  private bool dirty; // true if text was set externally (ie not read via UTF8 bytes)
33 
34  private UnicodeUtil.UTF16Result text = new UnicodeUtil.UTF16Result();
35  private UnicodeUtil.UTF8Result bytes = new UnicodeUtil.UTF8Result();
36 
37  public int CompareTo(TermBuffer other)
38  {
39  if ((System.Object) field == (System.Object) other.field)
40  // fields are interned
41  return CompareChars(text.result, text.length, other.text.result, other.text.length);
42  else
43  return String.CompareOrdinal(field, other.field);
44  }
45 
46  private static int CompareChars(char[] chars1, int len1, char[] chars2, int len2)
47  {
48  int end = len1 < len2?len1:len2;
49  for (int k = 0; k < end; k++)
50  {
51  char c1 = chars1[k];
52  char c2 = chars2[k];
53  if (c1 != c2)
54  {
55  return c1 - c2;
56  }
57  }
58  return len1 - len2;
59  }
60 
65  internal void SetPreUTF8Strings()
66  {
67  preUTF8Strings = true;
68  }
69 
70  public void Read(IndexInput input, FieldInfos fieldInfos)
71  {
72  this.term = null; // invalidate cache
73  int start = input.ReadVInt();
74  int length = input.ReadVInt();
75  int totalLength = start + length;
76  if (preUTF8Strings)
77  {
78  text.SetLength(totalLength);
79  input.ReadChars(text.result, start, length);
80  }
81  else
82  {
83 
84  if (dirty)
85  {
86  // Fully convert all bytes since bytes is dirty
87  UnicodeUtil.UTF16toUTF8(text.result, 0, text.length, bytes);
88  bytes.SetLength(totalLength);
89  input.ReadBytes(bytes.result, start, length);
90  UnicodeUtil.UTF8toUTF16(bytes.result, 0, totalLength, text);
91  dirty = false;
92  }
93  else
94  {
95  // Incrementally convert only the UTF8 bytes that are new:
96  bytes.SetLength(totalLength);
97  input.ReadBytes(bytes.result, start, length);
98  UnicodeUtil.UTF8toUTF16(bytes.result, start, length, text);
99  }
100  }
101  this.field = fieldInfos.FieldName(input.ReadVInt());
102  }
103 
104  public void Set(Term term)
105  {
106  if (term == null)
107  {
108  Reset();
109  return ;
110  }
111  System.String termText = term.Text;
112  int termLen = termText.Length;
113  text.SetLength(termLen);
114  TextSupport.GetCharsFromString(termText, 0, termLen, text.result, 0);
115  dirty = true;
116  field = term.Field;
117  this.term = term;
118  }
119 
120  public void Set(TermBuffer other)
121  {
122  text.CopyText(other.text);
123  dirty = true;
124  field = other.field;
125  term = other.term;
126  }
127 
128  public void Reset()
129  {
130  field = null;
131  text.SetLength(0);
132  term = null;
133  dirty = true;
134  }
135 
136  public Term ToTerm()
137  {
138  if (field == null)
139  // unset
140  return null;
141 
142  if (term == null)
143  term = new Term(field, new System.String(text.result, 0, text.length), false);
144 
145  return term;
146  }
147 
148  public System.Object Clone()
149  {
150  TermBuffer clone = null;
151  try
152  {
153  clone = (TermBuffer) base.MemberwiseClone();
154  }
155  catch (System.Exception)
156  {
157  }
158 
159  clone.dirty = true;
160  clone.bytes = new UnicodeUtil.UTF8Result();
161  clone.text = new UnicodeUtil.UTF16Result();
162  clone.text.CopyText(text);
163  return clone;
164  }
165  }
166 }