package org.apache.lucene.index;/** * Copyright 2004 The Apache Software Foundation * * Licensed 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.ByteArrayOutputStream;import java.io.IOException;import java.util.zip.DataFormatException;import java.util.zip.Inflater;import org.apache.lucene.document.Document;import org.apache.lucene.document.Field;import org.apache.lucene.store.Directory;import org.apache.lucene.store.IndexInput;/** * Class responsible for access to stored document fields. * * It uses &lt;segment&gt;.fdt and &lt;segment&gt;.fdx; files. * * @version $Id: FieldsReader.java 405870 2006-05-12 21:04:00Z dnaber $ */final class FieldsReader {  private FieldInfos fieldInfos;  private IndexInput fieldsStream;  private IndexInput indexStream;  private int size;  FieldsReader(Directory d, String segment, FieldInfos fn) throws IOException {    fieldInfos = fn;    fieldsStream = d.openInput(segment + ".fdt");    indexStream = d.openInput(segment + ".fdx");    size = (int)(indexStream.length() / 8);  }  final void close() throws IOException {    fieldsStream.close();    indexStream.close();  }  final int size() {    return size;  }  final Document doc(int n) throws IOException {    indexStream.seek(n * 8L);    long position = indexStream.readLong();    fieldsStream.seek(position);    Document doc = new Document();    int numFields = fieldsStream.readVInt();    for (int i = 0; i < numFields; i++) {      int fieldNumber = fieldsStream.readVInt();      FieldInfo fi = fieldInfos.fieldInfo(fieldNumber);      byte bits = fieldsStream.readByte();            boolean compressed = (bits & FieldsWriter.FIELD_IS_COMPRESSED) != 0;      boolean tokenize = (bits & FieldsWriter.FIELD_IS_TOKENIZED) != 0;            if ((bits & FieldsWriter.FIELD_IS_BINARY) != 0) {        final byte[] b = new byte[fieldsStream.readVInt()];        fieldsStream.readBytes(b, 0, b.length);        if (compressed)          doc.add(new Field(fi.name, uncompress(b), Field.Store.COMPRESS));        else          doc.add(new Field(fi.name, b, Field.Store.YES));      }      else {        Field.Index index;        Field.Store store = Field.Store.YES;                if (fi.isIndexed && tokenize)          index = Field.Index.TOKENIZED;        else if (fi.isIndexed && !tokenize)          index = Field.Index.UN_TOKENIZED;        else          index = Field.Index.NO;                Field.TermVector termVector = null;        if (fi.storeTermVector) {          if (fi.storeOffsetWithTermVector) {            if (fi.storePositionWithTermVector) {              termVector = Field.TermVector.WITH_POSITIONS_OFFSETS;            }            else {              termVector = Field.TermVector.WITH_OFFSETS;            }          }          else if (fi.storePositionWithTermVector) {            termVector = Field.TermVector.WITH_POSITIONS;          }          else {            termVector = Field.TermVector.YES;          }        }        else {          termVector = Field.TermVector.NO;        }                if (compressed) {          store = Field.Store.COMPRESS;          final byte[] b = new byte[fieldsStream.readVInt()];          fieldsStream.readBytes(b, 0, b.length);          Field f = new Field(fi.name,      // field name              new String(uncompress(b), "UTF-8"), // uncompress the value and add as string              store,              index,              termVector);          f.setOmitNorms(fi.omitNorms);          doc.add(f);        }        else {          Field f = new Field(fi.name,     // name                fieldsStream.readString(), // read value                store,                index,                termVector);          f.setOmitNorms(fi.omitNorms);          doc.add(f);        }      }    }    return doc;  }    private final byte[] uncompress(final byte[] input)    throws IOException  {      Inflater decompressor = new Inflater();    decompressor.setInput(input);      // Create an expandable byte array to hold the decompressed data    ByteArrayOutputStream bos = new ByteArrayOutputStream(input.length);      // Decompress the data    byte[] buf = new byte[1024];    while (!decompressor.finished()) {      try {        int count = decompressor.inflate(buf);        bos.write(buf, 0, count);      }      catch (DataFormatException e) {        // this will happen if the field is not compressed        IOException newException = new IOException("field data are in wrong format: " + e.toString());        newException.initCause(e);        throw newException;      }    }      decompressor.end();        // Get the decompressed data    return bos.toByteArray();  }}