package org.apache.lucene.analysis.ja.dict;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.lucene.codecs.CodecUtil;
  import org.apache.lucene.store.DataInput;
  import org.apache.lucene.store.InputStreamDataInput;
  import org.apache.lucene.util.BitUtil;
  import org.apache.lucene.util.IOUtils;
  
  /**
   * n-gram connection cost data
   */
  public final class ConnectionCosts {
    
    public static final String FILENAME_SUFFIX = ".dat";
    public static final String HEADER = "kuromoji_cc";
    public static final int VERSION = 1;
    
    private final short[][] costs; // array is backward IDs first since get is called using the same backward ID consecutively. maybe doesn't matter.
    
    private ConnectionCosts() throws IOException {
      InputStream is = null;
      short[][] costs = null;
      boolean success = false;
      try {
        is = BinaryDictionary.getClassResource(getClass(), FILENAME_SUFFIX);
        is = new BufferedInputStream(is);
        final DataInput in = new InputStreamDataInput(is);
        CodecUtil.checkHeader(in, HEADER, VERSION, VERSION);
        int forwardSize = in.readVInt();
        int backwardSize = in.readVInt();
        costs = new short[backwardSize][forwardSize];
        int accum = 0;
        for (int j = 0; j < costs.length; j++) {
          final short[] a = costs[j];
          for (int i = 0; i < a.length; i++) {
            accum += in.readZInt();
            a[i] = (short)accum;
          }
        }
        success = true;
      } finally {
        if (success) {
          IOUtils.close(is);
        } else {
          IOUtils.closeWhileHandlingException(is);
        }
      }
      
      this.costs = costs;
    }
    
    public int get(int forwardId, int backwardId) {
      return costs[backwardId][forwardId];
    }
    
    public static ConnectionCosts getInstance() {
      return SingletonHolder.INSTANCE;
    }
    
    private static class SingletonHolder {
      static final ConnectionCosts INSTANCE;
      static {
        try {
          INSTANCE = new ConnectionCosts();
        } catch (IOException ioe) {
          throw new RuntimeException("Cannot load ConnectionCosts.", ioe);
        }
      }
     }
    
  }