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