/**
* 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.
*/
package org.apache.hadoop.raid;
public interface ErasureCode {
/**
* Encodes the given message.
* @param message The data of the message. The data is present in the least
* significant bits of each int. The number of data bits is
* symbolSize(). The number of elements of message is
* stripeSize().
* @param parity (out) The information is present in the least
* significant bits of each int. The number of parity bits is
* symbolSize(). The number of elements in the code is
* paritySize().
*/
public void encode(int[] message, int[] parity);
/**
* Generates missing portions of data.
* @param data The message and parity. The parity should be placed in the
* first part of the array. In each integer, the relevant portion
* is present in the least significant bits of each int.
* The number of elements in data is stripeSize() + paritySize().
* @param erasedLocations The indexes in data which are not available.
* @param erasedValues (out)The decoded values corresponding to erasedLocations.
*/
public void decode(int[] data, int[] erasedLocations, int[] erasedValues);
/**
* The number of elements in the message.
*/
public int stripeSize();
/**
* The number of elements in the code.
*/
public int paritySize();
/**
* Number of bits for each symbol.
*/
public int symbolSize();
}