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ASF GitHub Bot logged work on HADOOP-17825: ------------------------------------------- Author: ASF GitHub Bot Created on: 13/Aug/21 19:36 Start Date: 13/Aug/21 19:36 Worklog Time Spent: 10m Work Description: sunchao commented on a change in pull request #3250: URL: https://github.com/apache/hadoop/pull/3250#discussion_r688739194 ########## File path: hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/BuiltInGzipCompressor.java ########## @@ -0,0 +1,261 @@ +/* + * 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.io.compress.zlib; + +import java.io.IOException; +import java.util.zip.Checksum; +import java.util.zip.Deflater; +import java.util.zip.GZIPOutputStream; + +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.io.compress.Compressor; +import org.apache.hadoop.io.compress.DoNotPool; +import org.apache.hadoop.util.DataChecksum; + +/** + * A {@link Compressor} based on the popular gzip compressed file format. + * http://www.gzip.org/ + */ +@DoNotPool +public class BuiltInGzipCompressor implements Compressor { + + /** + * Fixed ten-byte gzip header. See {@link GZIPOutputStream}'s source for + * details. + */ + private static final byte[] GZIP_HEADER = new byte[]{ + 0x1f, (byte) 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; + + // The trailer will be overwritten based on crc and output size. + private static final byte[] GZIP_TRAILER = new byte[]{ + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; + + private static final int GZIP_HEADER_LEN = GZIP_HEADER.length; + private static final int GZIP_TRAILER_LEN = GZIP_TRAILER.length; + + private Deflater deflater; + + private int headerOff = 0; + private int trailerOff = 0; + + private int numExtraBytesWritten = 0; + + private int currentBufLen = 0; + private int accuBufLen = 0; + + private final Checksum crc = DataChecksum.newCrc32(); + + private BuiltInGzipDecompressor.GzipStateLabel state; + + public BuiltInGzipCompressor(Configuration conf) { + init(conf); + } + + @Override + public boolean finished() { + // Only if the trailer is also written, it is thought as finished. + return state == BuiltInGzipDecompressor.GzipStateLabel.FINISHED && deflater.finished(); + } + + @Override + public boolean needsInput() { + return deflater.needsInput() && state != BuiltInGzipDecompressor.GzipStateLabel.TRAILER_CRC; + } + + @Override + public int compress(byte[] b, int off, int len) throws IOException { + if (finished()) { + throw new IOException("compress called on finished compressor"); + } + + int compressedBytesWritten = 0; + + if (currentBufLen <= 0) { + return compressedBytesWritten; + } + + // If we are not within uncompressed data yet, output the header. + if (state != BuiltInGzipDecompressor.GzipStateLabel.INFLATE_STREAM && + state != BuiltInGzipDecompressor.GzipStateLabel.TRAILER_CRC) { Review comment: yea, sorry `state == BuiltInGzipDecompressor.GzipStateLabel.HEADER_BASIC` - it is a stronger guarantee than the current one, is it? -- 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. To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org Issue Time Tracking ------------------- Worklog Id: (was: 637876) Time Spent: 22h 20m (was: 22h 10m) > Add BuiltInGzipCompressor > ------------------------- > > Key: HADOOP-17825 > URL: https://issues.apache.org/jira/browse/HADOOP-17825 > Project: Hadoop Common > Issue Type: Improvement > Reporter: L. C. Hsieh > Priority: Major > Labels: pull-request-available > Time Spent: 22h 20m > Remaining Estimate: 0h > > Currently, GzipCodec only supports BuiltInGzipDecompressor, if native zlib is > not loaded. So, without Hadoop native codec installed, saving SequenceFile > using GzipCodec will throw exception like "SequenceFile doesn't work with > GzipCodec without native-hadoop code!" > Same as other codecs which we migrated to using prepared packages (lz4, > snappy), it will be better if we support GzipCodec generally without Hadoop > native codec installed. Similar to BuiltInGzipDecompressor, we can use Java > Deflater to support BuiltInGzipCompressor. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org