Java tutorial
/** * 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.util; import java.nio.ByteBuffer; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class NativeJerasure { public static final Log LOG = LogFactory.getLog(NativeJerasure.class); /** * Return true if the JNI-based native Jerasure extensions are available. */ public static boolean isAvailable() { return NativeCodeLoader.isNativeCodeLoaded(); } public static native void nativeInit(int stripeSize, int paritySize); public static void encodeBulk(byte[][] inputs, byte[][] outputs, int stripeSize, int paritySize) { ByteBuffer[] inputBuffers = new ByteBuffer[inputs.length]; ByteBuffer[] outputBuffers = new ByteBuffer[outputs.length]; int bufferLen = inputs[0].length; for (int i = 0; i < outputs.length; i++) { outputBuffers[i] = ByteBuffer.allocateDirect(bufferLen); } for (int i = 0; i < inputs.length; i++) { inputBuffers[i] = directify(inputs[i], 0, bufferLen); } nativeEncodeBulk(inputBuffers, outputBuffers, stripeSize, paritySize, bufferLen); for (int i = 0; i < outputs.length; i++) { outputBuffers[i].get(outputs[i]); } } private static native void nativeEncodeBulk(ByteBuffer[] inputBuffers, ByteBuffer[] outputBuffers, int stripeSize, int paritySize, int dataLen); public static void decodeBulk(byte[][] readBufs, byte[][] writeBufs, int[] erasedLocation, int dataStart, int dataLen, int stripeSize, int paritySize) { ByteBuffer[] inputBuffers = new ByteBuffer[readBufs.length]; ByteBuffer[] outputBuffers = new ByteBuffer[writeBufs.length]; for (int i = 0; i < writeBufs.length; i++) { outputBuffers[i] = ByteBuffer.allocateDirect(dataLen); } for (int i = 0; i < readBufs.length; i++) { inputBuffers[i] = directify(readBufs[i], dataStart, dataLen); } nativeDecodeBulk(inputBuffers, outputBuffers, erasedLocation, dataLen, stripeSize, paritySize, erasedLocation.length); for (int i = 0; i < writeBufs.length; i++) { outputBuffers[i].get(writeBufs[i], dataStart, dataLen); } } private static native void nativeDecodeBulk(ByteBuffer[] inputBuffers, ByteBuffer[] outputBuffers, int[] erasedLocation, int dataLen, int stripeSize, int paritySize, int erasedLocationCount); private static ByteBuffer directify(byte[] readBufs, int dataStart, int dataLen) { ByteBuffer newBuf = null; newBuf = ByteBuffer.allocateDirect(dataLen); newBuf.position(0); newBuf.mark(); newBuf.put(readBufs, dataStart, dataLen); newBuf.reset(); newBuf.limit(dataLen); return newBuf; } }