turboFei commented on a change in pull request #28525: URL: https://github.com/apache/spark/pull/28525#discussion_r428495266
########## File path: common/network-common/src/main/java/org/apache/spark/network/util/DigestUtils.java ########## @@ -0,0 +1,69 @@ +/* + * 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.spark.network.util; + +import java.io.*; +import java.nio.ByteBuffer; +import java.nio.MappedByteBuffer; +import java.nio.channels.FileChannel; +import java.util.zip.CRC32; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class DigestUtils { + private static final Logger LOG = LoggerFactory.getLogger(DigestUtils.class); + private static final int STREAM_BUFFER_LENGTH = 8192; + private static final int DIGEST_LENGTH = 8; + + public static int getDigestLength() { + return DIGEST_LENGTH; + } + + public static long getDigest(InputStream data) throws IOException { + CRC32 crc32 = new CRC32(); + byte[] buffer = new byte[STREAM_BUFFER_LENGTH]; + int len; + while ((len = data.read(buffer)) >= 0) { + crc32.update(buffer, 0, len); + } + return crc32.getValue(); + } + + public static long getDigest(File file, long offset, long length) { + if (length <= 0) { + return -1L; + } + try (RandomAccessFile rf = new RandomAccessFile(file, "r")) { + MappedByteBuffer data = rf.getChannel().map(FileChannel.MapMode.READ_ONLY, offset, + length); + CRC32 crc32 = new CRC32(); + byte[] buffer = new byte[STREAM_BUFFER_LENGTH]; + int len; + while ((len = Math.min(STREAM_BUFFER_LENGTH, data.remaining())) > 0) { + data.get(buffer, 0, len); + crc32.update(buffer, 0, len); + } + return crc32.getValue(); + } catch (IOException e) { + LOG.error(String.format("Exception while computing digest for file segment: " + + "%s(offset:%d, length:%d)", file.getName(), offset, length )); + return -1L; + } + } +} Review comment: thx ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
