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DWRF file format for Hive

There is a newer version: 0.18.9

//  Copyright (c) 2013, Facebook, Inc.  All rights reserved.

/**
 * 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.
 */

/**
 * The Optimized Row Columnar (ORC) File Format.
 *
 * This format:
 * 
 *   Decomposes complex column types into primitives
 *   Uses type-specific encoders for each column
 *     
 *       Dictionary encodings for low cardinality columns
 *       Run length encoding of data
 *       variable length encoding of integers
 *     
 *   
 *   Divides file into large stripes
 *   Each stripe includes light-weight indexes that enable the reader to
 *     skip large sets of rows that don't satisfy the filter condition
 *   A file footer that contains meta-information about file
 *     
 *       Precise byte range for each stripe
 *       Type information for the file
 *       Any user meta-information
 *     
 *   
 *   Seek to row number is implemented to support secondary indexes
 *   Support for additional generic compression: LZO, SNAPPY, ZLIB.
 * 
 *
 * 
 * Format:
 * 
 * {@code
 * HEADER (3 bytes) "ORC"
 * STRIPE (0 or more stripes)
 * FILE-FOOTER
 * POST SCRIPT
 * PS LENGTH (1 byte)
 * }
 * 
 * 
 *
 * 
 * Stripe:
 * 
 * {@code
 * INDEX-STREAM (0 or more)
 * DATA-STREAM (0 or more)
 * STRIPE-FOOTER
 * }
 * 
 * 
 */
package com.facebook.hive.orc;