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<div class="title">FuzzyTermEnum.cs</div> </div>
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<a href="_fuzzy_term_enum_8cs.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">/* </span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment"> * contributor license agreements. See the NOTICE file distributed with</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment"> * this work for additional information regarding copyright ownership.</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;<span class="comment"> * (the &quot;License&quot;); you may not use this file except in compliance with</span></div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="comment"> * the License. You may obtain a copy of the License at</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;<span class="comment"> * </span></div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="comment"> * http://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;<span class="comment"> * </span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="comment"> * Unless required by applicable law or agreed to in writing, software</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;<span class="comment"> * distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span></div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;<span class="comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;<span class="comment"> * See the License for the specific language governing permissions and</span></div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="comment"> * limitations under the License.</span></div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160;</div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160;<span class="keyword">using</span> System;</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160;</div>
<div class="line"><a name="l00020"></a><span class="lineno"><a class="code" href="_fuzzy_term_enum_8cs.html#a2a6914ea10bbe06764856e29e5674e66"> 20</a></span>&#160;<span class="keyword">using</span> <a class="code" href="_more_like_this_8cs.html#a2a6914ea10bbe06764856e29e5674e66">IndexReader</a> = Lucene.Net.Index.IndexReader;</div>
<div class="line"><a name="l00021"></a><span class="lineno"><a class="code" href="_fuzzy_term_enum_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9"> 21</a></span>&#160;<span class="keyword">using</span> <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> = Lucene.Net.Index.Term;</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160;<span class="keyword">namespace </span>Lucene.Net.Search</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160;{</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160; </div>
<div class="line"><a name="l00032"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html"> 32</a></span>&#160; <span class="keyword">public</span> sealed <span class="keyword">class </span><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html" title="Subclass of FilteredTermEnum for enumerating all terms that are similiar to the specified filter term...">FuzzyTermEnum</a>:<a class="code" href="class_lucene_1_1_net_1_1_search_1_1_filtered_term_enum.html" title="Abstract class for enumerating a subset of all terms. Term enumerations are always ordered by Term...">FilteredTermEnum</a></div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160; {</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160; <span class="comment">/* Allows us save time required to create a new array</span></div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160;<span class="comment"> * everytime similarity is called.</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160;<span class="comment"> */</span></div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160; <span class="keyword">private</span> <span class="keywordtype">int</span>[] p;</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160; <span class="keyword">private</span> <span class="keywordtype">int</span>[] d;</div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160; </div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; <span class="keyword">private</span> <span class="keywordtype">float</span> similarity;</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160; <span class="keyword">private</span> <span class="keywordtype">bool</span> endEnum = <span class="keyword">false</span>;</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160;</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160; <span class="keyword">private</span> <span class="keywordtype">bool</span> isDisposed;</div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160;</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160; <span class="keyword">private</span> <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> searchTerm = null;</div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160; <span class="keyword">private</span> System.String field;</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; <span class="keyword">private</span> System.String text;</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; <span class="keyword">private</span> System.String prefix;</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160; </div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160; <span class="keyword">private</span> <span class="keywordtype">float</span> minimumSimilarity;</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160; <span class="keyword">private</span> <span class="keywordtype">float</span> scale_factor;</div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160; </div>
<div class="line"><a name="l00066"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#ae1a05375744caabc0f9c2b88fde4e4ee"> 66</a></span>&#160; <span class="keyword">public</span> <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html" title="Subclass of FilteredTermEnum for enumerating all terms that are similiar to the specified filter term...">FuzzyTermEnum</a>(<a class="code" href="_more_like_this_8cs.html#a2a6914ea10bbe06764856e29e5674e66">IndexReader</a> reader, <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> term):this(reader, term, <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_query.html" title="Implements the fuzzy search query. The similarity measurement is based on the Levenshtein (edit dista...">FuzzyQuery</a>.defaultMinSimilarity, <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_query.html" title="Implements the fuzzy search query. The similarity measurement is based on the Levenshtein (edit dista...">FuzzyQuery</a>.defaultPrefixLength)</div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160; {</div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160; }</div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160; </div>
<div class="line"><a name="l00085"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#a2eb63e9fc22a91531bb1bf73e701b283"> 85</a></span>&#160; <span class="keyword">public</span> <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html" title="Subclass of FilteredTermEnum for enumerating all terms that are similiar to the specified filter term...">FuzzyTermEnum</a>(<a class="code" href="_more_like_this_8cs.html#a2a6914ea10bbe06764856e29e5674e66">IndexReader</a> reader, <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> term, <span class="keywordtype">float</span> minSimilarity):this(reader, term, minSimilarity, <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_query.html" title="Implements the fuzzy search query. The similarity measurement is based on the Levenshtein (edit dista...">FuzzyQuery</a>.defaultPrefixLength)</div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160; {</div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160; }</div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160; </div>
<div class="line"><a name="l00106"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#a4fd52b7f8693a8db988f95111eb0abda"> 106</a></span>&#160; <span class="keyword">public</span> <a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html" title="Subclass of FilteredTermEnum for enumerating all terms that are similiar to the specified filter term...">FuzzyTermEnum</a>(<a class="code" href="_more_like_this_8cs.html#a2a6914ea10bbe06764856e29e5674e66">IndexReader</a> reader, <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> term, <span class="keywordtype">float</span> minSimilarity, <span class="keywordtype">int</span> prefixLength):base()</div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160; {</div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160; </div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160; <span class="keywordflow">if</span> (minSimilarity &gt;= 1.0f)</div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160; <span class="keywordflow">throw</span> <span class="keyword">new</span> System.ArgumentException(<span class="stringliteral">&quot;minimumSimilarity cannot be greater than or equal to 1&quot;</span>);</div>
<div class="line"><a name="l00111"></a><span class="lineno"> 111</span>&#160; <span class="keywordflow">else</span> <span class="keywordflow">if</span> (minSimilarity &lt; 0.0f)</div>
<div class="line"><a name="l00112"></a><span class="lineno"> 112</span>&#160; <span class="keywordflow">throw</span> <span class="keyword">new</span> System.ArgumentException(<span class="stringliteral">&quot;minimumSimilarity cannot be less than 0&quot;</span>);</div>
<div class="line"><a name="l00113"></a><span class="lineno"> 113</span>&#160; <span class="keywordflow">if</span> (prefixLength &lt; 0)</div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160; <span class="keywordflow">throw</span> <span class="keyword">new</span> System.ArgumentException(<span class="stringliteral">&quot;prefixLength cannot be less than 0&quot;</span>);</div>
<div class="line"><a name="l00115"></a><span class="lineno"> 115</span>&#160; </div>
<div class="line"><a name="l00116"></a><span class="lineno"> 116</span>&#160; this.minimumSimilarity = minSimilarity;</div>
<div class="line"><a name="l00117"></a><span class="lineno"> 117</span>&#160; this.scale_factor = 1.0f / (1.0f - minimumSimilarity);</div>
<div class="line"><a name="l00118"></a><span class="lineno"> 118</span>&#160; this.searchTerm = term;</div>
<div class="line"><a name="l00119"></a><span class="lineno"> 119</span>&#160; this.field = searchTerm.Field;</div>
<div class="line"><a name="l00120"></a><span class="lineno"> 120</span>&#160; </div>
<div class="line"><a name="l00121"></a><span class="lineno"> 121</span>&#160; <span class="comment">//The prefix could be longer than the word.</span></div>
<div class="line"><a name="l00122"></a><span class="lineno"> 122</span>&#160; <span class="comment">//It&#39;s kind of silly though. It means we must match the entire word.</span></div>
<div class="line"><a name="l00123"></a><span class="lineno"> 123</span>&#160; <span class="keywordtype">int</span> fullSearchTermLength = searchTerm.Text.Length;</div>
<div class="line"><a name="l00124"></a><span class="lineno"> 124</span>&#160; <span class="keywordtype">int</span> realPrefixLength = prefixLength &gt; fullSearchTermLength?fullSearchTermLength:prefixLength;</div>
<div class="line"><a name="l00125"></a><span class="lineno"> 125</span>&#160; </div>
<div class="line"><a name="l00126"></a><span class="lineno"> 126</span>&#160; this.text = searchTerm.Text.Substring(realPrefixLength);</div>
<div class="line"><a name="l00127"></a><span class="lineno"> 127</span>&#160; this.prefix = searchTerm.Text.Substring(0, (realPrefixLength) - (0));</div>
<div class="line"><a name="l00128"></a><span class="lineno"> 128</span>&#160;</div>
<div class="line"><a name="l00129"></a><span class="lineno"> 129</span>&#160; this.p = <span class="keyword">new</span> <span class="keywordtype">int</span>[this.text.Length + 1];</div>
<div class="line"><a name="l00130"></a><span class="lineno"> 130</span>&#160; this.d = <span class="keyword">new</span> <span class="keywordtype">int</span>[this.text.Length + 1];</div>
<div class="line"><a name="l00131"></a><span class="lineno"> 131</span>&#160; </div>
<div class="line"><a name="l00132"></a><span class="lineno"> 132</span>&#160; SetEnum(reader.Terms(<span class="keyword">new</span> <a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a>(searchTerm.Field, prefix)));</div>
<div class="line"><a name="l00133"></a><span class="lineno"> 133</span>&#160; }</div>
<div class="line"><a name="l00134"></a><span class="lineno"> 134</span>&#160; </div>
<div class="line"><a name="l00138"></a><span class="lineno"> 138</span>&#160; <span class="keyword">protected</span> <span class="keyword">internal</span> <span class="keyword">override</span> <span class="keywordtype">bool</span> TermCompare(<a class="code" href="_more_like_this_8cs.html#a8797eb30ce21b31829d3e3a43a20e3b9">Term</a> term)</div>
<div class="line"><a name="l00139"></a><span class="lineno"> 139</span>&#160; {</div>
<div class="line"><a name="l00140"></a><span class="lineno"> 140</span>&#160; <span class="keywordflow">if</span> ((System.Object) field == (System.Object) term.Field &amp;&amp; term.Text.StartsWith(prefix))</div>
<div class="line"><a name="l00141"></a><span class="lineno"> 141</span>&#160; {</div>
<div class="line"><a name="l00142"></a><span class="lineno"> 142</span>&#160; System.String target = term.Text.Substring(prefix.Length);</div>
<div class="line"><a name="l00143"></a><span class="lineno"> 143</span>&#160; this.similarity = <a class="code" href="_documents_writer_8cs.html#a5431a3a4edd067eec50ca39b5ea99c31">Similarity</a>(target);</div>
<div class="line"><a name="l00144"></a><span class="lineno"> 144</span>&#160; <span class="keywordflow">return</span> (similarity &gt; minimumSimilarity);</div>
<div class="line"><a name="l00145"></a><span class="lineno"> 145</span>&#160; }</div>
<div class="line"><a name="l00146"></a><span class="lineno"> 146</span>&#160; endEnum = <span class="keyword">true</span>;</div>
<div class="line"><a name="l00147"></a><span class="lineno"> 147</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00148"></a><span class="lineno"> 148</span>&#160; }</div>
<div class="line"><a name="l00149"></a><span class="lineno"> 149</span>&#160; </div>
<div class="line"><a name="l00150"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#a6ff05fcbb96c2d3bd5568e9069c87741"> 150</a></span>&#160; <span class="keyword">public</span> <span class="keyword">override</span> <span class="keywordtype">float</span> Difference()</div>
<div class="line"><a name="l00151"></a><span class="lineno"> 151</span>&#160; {</div>
<div class="line"><a name="l00152"></a><span class="lineno"> 152</span>&#160; <span class="keywordflow">return</span> ((similarity - minimumSimilarity) * scale_factor);</div>
<div class="line"><a name="l00153"></a><span class="lineno"> 153</span>&#160; }</div>
<div class="line"><a name="l00154"></a><span class="lineno"> 154</span>&#160; </div>
<div class="line"><a name="l00155"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#a35b90d54e3ed942ca2608130d7ce478d"> 155</a></span>&#160; <span class="keyword">public</span> <span class="keyword">override</span> <span class="keywordtype">bool</span> EndEnum()</div>
<div class="line"><a name="l00156"></a><span class="lineno"> 156</span>&#160; {</div>
<div class="line"><a name="l00157"></a><span class="lineno"> 157</span>&#160; <span class="keywordflow">return</span> endEnum;</div>
<div class="line"><a name="l00158"></a><span class="lineno"> 158</span>&#160; }</div>
<div class="line"><a name="l00159"></a><span class="lineno"> 159</span>&#160; </div>
<div class="line"><a name="l00160"></a><span class="lineno"> 160</span>&#160; <span class="comment">// &lt;summary&gt;</span></div>
<div class="line"><a name="l00161"></a><span class="lineno"> 161</span>&#160; <span class="comment">// ***************************</span></div>
<div class="line"><a name="l00162"></a><span class="lineno"> 162</span>&#160; <span class="comment">// Compute Levenshtein distance</span></div>
<div class="line"><a name="l00163"></a><span class="lineno"> 163</span>&#160; <span class="comment">// ****************************</span></div>
<div class="line"><a name="l00164"></a><span class="lineno"> 164</span>&#160; <span class="comment">// &lt;/summary&gt;</span></div>
<div class="line"><a name="l00165"></a><span class="lineno"> 165</span>&#160; </div>
<div class="line"><a name="l00204"></a><span class="lineno"> 204</span>&#160; <span class="keyword">private</span> <span class="keywordtype">float</span> <a class="code" href="_documents_writer_8cs.html#a5431a3a4edd067eec50ca39b5ea99c31">Similarity</a>(System.String target)</div>
<div class="line"><a name="l00205"></a><span class="lineno"> 205</span>&#160; {</div>
<div class="line"><a name="l00206"></a><span class="lineno"> 206</span>&#160;</div>
<div class="line"><a name="l00207"></a><span class="lineno"> 207</span>&#160; <span class="keywordtype">int</span> m = target.Length;</div>
<div class="line"><a name="l00208"></a><span class="lineno"> 208</span>&#160; <span class="keywordtype">int</span> n = text.Length;</div>
<div class="line"><a name="l00209"></a><span class="lineno"> 209</span>&#160; <span class="keywordflow">if</span> (n == 0)</div>
<div class="line"><a name="l00210"></a><span class="lineno"> 210</span>&#160; {</div>
<div class="line"><a name="l00211"></a><span class="lineno"> 211</span>&#160; <span class="comment">//we don&#39;t have anything to compare. That means if we just add</span></div>
<div class="line"><a name="l00212"></a><span class="lineno"> 212</span>&#160; <span class="comment">//the letters for m we get the new word</span></div>
<div class="line"><a name="l00213"></a><span class="lineno"> 213</span>&#160; <span class="keywordflow">return</span> prefix.Length == 0 ? 0.0f : 1.0f - ((float)m / prefix.Length);</div>
<div class="line"><a name="l00214"></a><span class="lineno"> 214</span>&#160; }</div>
<div class="line"><a name="l00215"></a><span class="lineno"> 215</span>&#160; <span class="keywordflow">if</span> (m == 0)</div>
<div class="line"><a name="l00216"></a><span class="lineno"> 216</span>&#160; {</div>
<div class="line"><a name="l00217"></a><span class="lineno"> 217</span>&#160; <span class="keywordflow">return</span> prefix.Length == 0 ? 0.0f : 1.0f - ((float)n / prefix.Length);</div>
<div class="line"><a name="l00218"></a><span class="lineno"> 218</span>&#160; }</div>
<div class="line"><a name="l00219"></a><span class="lineno"> 219</span>&#160;</div>
<div class="line"><a name="l00220"></a><span class="lineno"> 220</span>&#160; <span class="keywordtype">int</span> maxDistance = CalculateMaxDistance(m);</div>
<div class="line"><a name="l00221"></a><span class="lineno"> 221</span>&#160;</div>
<div class="line"><a name="l00222"></a><span class="lineno"> 222</span>&#160; <span class="keywordflow">if</span> (maxDistance &lt; System.Math.Abs(m - n))</div>
<div class="line"><a name="l00223"></a><span class="lineno"> 223</span>&#160; {</div>
<div class="line"><a name="l00224"></a><span class="lineno"> 224</span>&#160; <span class="comment">//just adding the characters of m to n or vice-versa results in</span></div>
<div class="line"><a name="l00225"></a><span class="lineno"> 225</span>&#160; <span class="comment">//too many edits</span></div>
<div class="line"><a name="l00226"></a><span class="lineno"> 226</span>&#160; <span class="comment">//for example &quot;pre&quot; length is 3 and &quot;prefixes&quot; length is 8. We can see that</span></div>
<div class="line"><a name="l00227"></a><span class="lineno"> 227</span>&#160; <span class="comment">//given this optimal circumstance, the edit distance cannot be less than 5.</span></div>
<div class="line"><a name="l00228"></a><span class="lineno"> 228</span>&#160; <span class="comment">//which is 8-3 or more precisesly Math.abs(3-8).</span></div>
<div class="line"><a name="l00229"></a><span class="lineno"> 229</span>&#160; <span class="comment">//if our maximum edit distance is 4, then we can discard this word</span></div>
<div class="line"><a name="l00230"></a><span class="lineno"> 230</span>&#160; <span class="comment">//without looking at it.</span></div>
<div class="line"><a name="l00231"></a><span class="lineno"> 231</span>&#160; <span class="keywordflow">return</span> 0.0f;</div>
<div class="line"><a name="l00232"></a><span class="lineno"> 232</span>&#160; }</div>
<div class="line"><a name="l00233"></a><span class="lineno"> 233</span>&#160;</div>
<div class="line"><a name="l00234"></a><span class="lineno"> 234</span>&#160; <span class="comment">// init matrix d</span></div>
<div class="line"><a name="l00235"></a><span class="lineno"> 235</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i &lt; n; ++i)</div>
<div class="line"><a name="l00236"></a><span class="lineno"> 236</span>&#160; {</div>
<div class="line"><a name="l00237"></a><span class="lineno"> 237</span>&#160; p[i] = i;</div>
<div class="line"><a name="l00238"></a><span class="lineno"> 238</span>&#160; }</div>
<div class="line"><a name="l00239"></a><span class="lineno"> 239</span>&#160;</div>
<div class="line"><a name="l00240"></a><span class="lineno"> 240</span>&#160; <span class="comment">// start computing edit distance</span></div>
<div class="line"><a name="l00241"></a><span class="lineno"> 241</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">int</span> j = 1; j &lt;= m; ++j)</div>
<div class="line"><a name="l00242"></a><span class="lineno"> 242</span>&#160; {</div>
<div class="line"><a name="l00243"></a><span class="lineno"> 243</span>&#160; <span class="keywordtype">int</span> bestPossibleEditDistance = m;</div>
<div class="line"><a name="l00244"></a><span class="lineno"> 244</span>&#160; <span class="keywordtype">char</span> t_j = target[j - 1];</div>
<div class="line"><a name="l00245"></a><span class="lineno"> 245</span>&#160; d[0] = j;</div>
<div class="line"><a name="l00246"></a><span class="lineno"> 246</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 1; i &lt;= n; ++i)</div>
<div class="line"><a name="l00247"></a><span class="lineno"> 247</span>&#160; {</div>
<div class="line"><a name="l00248"></a><span class="lineno"> 248</span>&#160; <span class="comment">// minimum of cell to the left+1, to the top+1, diagonally left and up +(0|1)</span></div>
<div class="line"><a name="l00249"></a><span class="lineno"> 249</span>&#160; <span class="keywordflow">if</span> (t_j != text[i - 1])</div>
<div class="line"><a name="l00250"></a><span class="lineno"> 250</span>&#160; {</div>
<div class="line"><a name="l00251"></a><span class="lineno"> 251</span>&#160; d[i] = Math.Min(Math.Min(d[i - 1], p[i]), p[i - 1]) + 1;</div>
<div class="line"><a name="l00252"></a><span class="lineno"> 252</span>&#160; }</div>
<div class="line"><a name="l00253"></a><span class="lineno"> 253</span>&#160; <span class="keywordflow">else</span></div>
<div class="line"><a name="l00254"></a><span class="lineno"> 254</span>&#160; {</div>
<div class="line"><a name="l00255"></a><span class="lineno"> 255</span>&#160; d[i] = Math.Min(Math.Min(d[i - 1] + 1, p[i] + 1), p[i - 1]);</div>
<div class="line"><a name="l00256"></a><span class="lineno"> 256</span>&#160; }</div>
<div class="line"><a name="l00257"></a><span class="lineno"> 257</span>&#160; bestPossibleEditDistance = System.Math.Min(bestPossibleEditDistance, d[i]);</div>
<div class="line"><a name="l00258"></a><span class="lineno"> 258</span>&#160; }</div>
<div class="line"><a name="l00259"></a><span class="lineno"> 259</span>&#160;</div>
<div class="line"><a name="l00260"></a><span class="lineno"> 260</span>&#160; <span class="comment">//After calculating row i, the best possible edit distance</span></div>
<div class="line"><a name="l00261"></a><span class="lineno"> 261</span>&#160; <span class="comment">//can be found by found by finding the smallest value in a given column.</span></div>
<div class="line"><a name="l00262"></a><span class="lineno"> 262</span>&#160; <span class="comment">//If the bestPossibleEditDistance is greater than the max distance, abort.</span></div>
<div class="line"><a name="l00263"></a><span class="lineno"> 263</span>&#160;</div>
<div class="line"><a name="l00264"></a><span class="lineno"> 264</span>&#160; <span class="keywordflow">if</span> (j &gt; maxDistance &amp;&amp; bestPossibleEditDistance &gt; maxDistance)</div>
<div class="line"><a name="l00265"></a><span class="lineno"> 265</span>&#160; {</div>
<div class="line"><a name="l00266"></a><span class="lineno"> 266</span>&#160; <span class="comment">//equal is okay, but not greater</span></div>
<div class="line"><a name="l00267"></a><span class="lineno"> 267</span>&#160; <span class="comment">//the closest the target can be to the text is just too far away.</span></div>
<div class="line"><a name="l00268"></a><span class="lineno"> 268</span>&#160; <span class="comment">//this target is leaving the party early.</span></div>
<div class="line"><a name="l00269"></a><span class="lineno"> 269</span>&#160; <span class="keywordflow">return</span> 0.0f;</div>
<div class="line"><a name="l00270"></a><span class="lineno"> 270</span>&#160; }</div>
<div class="line"><a name="l00271"></a><span class="lineno"> 271</span>&#160;</div>
<div class="line"><a name="l00272"></a><span class="lineno"> 272</span>&#160; <span class="comment">// copy current distance counts to &#39;previous row&#39; distance counts: swap p and d</span></div>
<div class="line"><a name="l00273"></a><span class="lineno"> 273</span>&#160; <span class="keywordtype">int</span>[] _d = p;</div>
<div class="line"><a name="l00274"></a><span class="lineno"> 274</span>&#160; p = d;</div>
<div class="line"><a name="l00275"></a><span class="lineno"> 275</span>&#160; d = _d;</div>
<div class="line"><a name="l00276"></a><span class="lineno"> 276</span>&#160; }</div>
<div class="line"><a name="l00277"></a><span class="lineno"> 277</span>&#160;</div>
<div class="line"><a name="l00278"></a><span class="lineno"> 278</span>&#160; <span class="comment">// our last action in the above loop was to switch d and p, so p now</span></div>
<div class="line"><a name="l00279"></a><span class="lineno"> 279</span>&#160; <span class="comment">// actually has the most recent cost counts</span></div>
<div class="line"><a name="l00280"></a><span class="lineno"> 280</span>&#160;</div>
<div class="line"><a name="l00281"></a><span class="lineno"> 281</span>&#160; <span class="comment">// this will return less than 0.0 when the edit distance is</span></div>
<div class="line"><a name="l00282"></a><span class="lineno"> 282</span>&#160; <span class="comment">// greater than the number of characters in the shorter word.</span></div>
<div class="line"><a name="l00283"></a><span class="lineno"> 283</span>&#160; <span class="comment">// but this was the formula that was previously used in FuzzyTermEnum,</span></div>
<div class="line"><a name="l00284"></a><span class="lineno"> 284</span>&#160; <span class="comment">// so it has not been changed (even though minimumSimilarity must be</span></div>
<div class="line"><a name="l00285"></a><span class="lineno"> 285</span>&#160; <span class="comment">// greater than 0.0)</span></div>
<div class="line"><a name="l00286"></a><span class="lineno"> 286</span>&#160; <span class="keywordflow">return</span> 1.0f - (p[n] / (float)(prefix.Length + System.Math.Min(n, m)));</div>
<div class="line"><a name="l00287"></a><span class="lineno"> 287</span>&#160;</div>
<div class="line"><a name="l00288"></a><span class="lineno"> 288</span>&#160; }</div>
<div class="line"><a name="l00289"></a><span class="lineno"> 289</span>&#160; </div>
<div class="line"><a name="l00298"></a><span class="lineno"> 298</span>&#160; <span class="keyword">private</span> <span class="keywordtype">int</span> CalculateMaxDistance(<span class="keywordtype">int</span> m)</div>
<div class="line"><a name="l00299"></a><span class="lineno"> 299</span>&#160; {</div>
<div class="line"><a name="l00300"></a><span class="lineno"> 300</span>&#160; <span class="keywordflow">return</span> (<span class="keywordtype">int</span>) ((1 - minimumSimilarity) * (System.Math.Min(text.Length, m) + prefix.Length));</div>
<div class="line"><a name="l00301"></a><span class="lineno"> 301</span>&#160; }</div>
<div class="line"><a name="l00302"></a><span class="lineno"> 302</span>&#160;</div>
<div class="line"><a name="l00303"></a><span class="lineno"><a class="code" href="class_lucene_1_1_net_1_1_search_1_1_fuzzy_term_enum.html#aa557a701d66fd10e216a847cfb99c2cb"> 303</a></span>&#160; <span class="keyword">protected</span> <span class="keyword">override</span> <span class="keywordtype">void</span> Dispose(<span class="keywordtype">bool</span> disposing)</div>
<div class="line"><a name="l00304"></a><span class="lineno"> 304</span>&#160; {</div>
<div class="line"><a name="l00305"></a><span class="lineno"> 305</span>&#160; <span class="keywordflow">if</span> (isDisposed) <span class="keywordflow">return</span>;</div>
<div class="line"><a name="l00306"></a><span class="lineno"> 306</span>&#160;</div>
<div class="line"><a name="l00307"></a><span class="lineno"> 307</span>&#160; <span class="keywordflow">if</span> (disposing)</div>
<div class="line"><a name="l00308"></a><span class="lineno"> 308</span>&#160; {</div>
<div class="line"><a name="l00309"></a><span class="lineno"> 309</span>&#160; p = null;</div>
<div class="line"><a name="l00310"></a><span class="lineno"> 310</span>&#160; d = null;</div>
<div class="line"><a name="l00311"></a><span class="lineno"> 311</span>&#160; searchTerm = null;</div>
<div class="line"><a name="l00312"></a><span class="lineno"> 312</span>&#160; }</div>
<div class="line"><a name="l00313"></a><span class="lineno"> 313</span>&#160;</div>
<div class="line"><a name="l00314"></a><span class="lineno"> 314</span>&#160; isDisposed = <span class="keyword">true</span>;</div>
<div class="line"><a name="l00315"></a><span class="lineno"> 315</span>&#160; base.Dispose(disposing); <span class="comment">//call super.close() and let the garbage collector do its work.</span></div>
<div class="line"><a name="l00316"></a><span class="lineno"> 316</span>&#160; }</div>
<div class="line"><a name="l00317"></a><span class="lineno"> 317</span>&#160; }</div>
<div class="line"><a name="l00318"></a><span class="lineno"> 318</span>&#160;}</div>
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