| <!-- |
| 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. |
| --> |
| <html> |
| <head> |
| <title>Serialization Formats for Mutation</title> |
| </head> |
| <body> |
| <p> |
| The <code>Mutation</code> class supports two serialization formats. |
| While it only currently serializes to the newer version 2 format, it |
| can read both version 1 and version 2 serialized forms. |
| </p> |
| |
| <h2>Version 1 Format</h2> |
| <table> |
| <caption>Version 1 mutation data serialization layout</caption> |
| <tr> |
| <th>data location</th> |
| <th>description</th> |
| </tr> |
| <tr> |
| <td>bytes 0 through 3</td> |
| <td>4-byte integer for length of row ID</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>row ID</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>data length</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>data (see below)</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>number of entries</td> |
| </tr> |
| <tr> |
| <td>next boolean</td> |
| <td>values present flag</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>number of values (only if values present flag is set)</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> sets of integers and byte arrays</td> |
| <td><i>n</i> value lengths and value data bytes (only if values |
| present flag is set)</td> |
| </tr> |
| </table> |
| <table> |
| <caption>Version 1 "data" block layout for each entry</caption> |
| <tr> |
| <td>first integer and byte array</td> |
| <td>column family length and bytes</td> |
| </tr> |
| <tr> |
| <td>next integer and byte array</td> |
| <td>column qualifier length and bytes</td> |
| </tr> |
| <tr> |
| <td>next integer and byte array</td> |
| <td>column visibility length and bytes</td> |
| </tr> |
| <tr> |
| <td>next boolean</td> |
| <td>has timestamp flag</td> |
| </tr> |
| <tr> |
| <td>next long</td> |
| <td>timestamp</td> |
| </tr> |
| <tr> |
| <td>next boolean</td> |
| <td>deleted flag</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>value length; if negative, value bytes are the same as those |
| for already-read value (-length - 1)</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>value bytes (only if value length is non-negative)</td> |
| </tr> |
| </table> |
| |
| <h2>Version 2 Format</h2> |
| <table> |
| <caption> |
| Version 2 mutation data serialization layout<br> |
| (variable length encoding for integers and longs) |
| </caption> |
| <tr> |
| <th>data location</th> |
| <th>description</th> |
| </tr> |
| <tr> |
| <td>byte 0</td> |
| <td>control byte: top bit = 1 for version 2; bottom bit = |
| values present flag</td> |
| </tr> |
| <tr> |
| <td>next integer |
| <td>length of row ID</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>row ID</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>data length</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>data (see below)</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>number of entries</td> |
| </tr> |
| <tr> |
| <td>next integer</td> |
| <td>number of values (only if values present flag is set)</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> sets of integers and byte arrays</td> |
| <td><i>n</i> value lengths and value data bytes (only if values |
| present flag is set)</td> |
| </tr> |
| </table> |
| <table> |
| <caption>Version 2 "data" block layout for each entry</caption> |
| <tr> |
| <td>first long and byte array</td> |
| <td>column family length and bytes</td> |
| </tr> |
| <tr> |
| <td>next long and byte array</td> |
| <td>column qualifier length and bytes</td> |
| </tr> |
| <tr> |
| <td>next long and byte array</td> |
| <td>column visibility length and bytes</td> |
| </tr> |
| <tr> |
| <td>next boolean</td> |
| <td>has timestamp flag</td> |
| </tr> |
| <tr> |
| <td>next long</td> |
| <td>timestamp (only present if timestamp flag is set)</td> |
| </tr> |
| <tr> |
| <td>next boolean</td> |
| <td>deleted flag</td> |
| </tr> |
| <tr> |
| <td>next long</td> |
| <td>value length; if negative, value bytes are the same as those |
| for already-read value (-length - 1)</td> |
| </tr> |
| <tr> |
| <td>next <i>n</i> bytes</td> |
| <td>value bytes (only if value length is non-negative)</td> |
| </tr> |
| </table> |
| </body> |
| </html> |
