/** * 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.mapreduce.lib.input; import java.io.IOException; import java.io.InputStream; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.io.Text; /** * SplitLineReader for uncompressed files. * This class can split the file correctly even if the delimiter is multi-bytes. */ @InterfaceAudience.Private @InterfaceStability.Unstable public class UncompressedSplitLineReader extends SplitLineReader { private boolean needAdditionalRecord = false; private long splitLength; /** Total bytes read from the input stream. */ private long totalBytesRead = 0; private boolean finished = false; private boolean usingCRLF; private int unusedBytes = 0; private int lastBytesRead = 0; public UncompressedSplitLineReader(FSDataInputStream in, Configuration conf, byte[] recordDelimiterBytes, long splitLength) throws IOException { super(in, conf, recordDelimiterBytes); this.splitLength = splitLength; usingCRLF = (recordDelimiterBytes == null); } @Override protected int fillBuffer(InputStream in, byte[] buffer, boolean inDelimiter) throws IOException { int maxBytesToRead = buffer.length; if (totalBytesRead < splitLength) { maxBytesToRead = Math.min(maxBytesToRead, (int)(splitLength - totalBytesRead)); } int bytesRead = in.read(buffer, 0, maxBytesToRead); lastBytesRead = bytesRead; // If the split ended in the middle of a record delimiter then we need // to read one additional record, as the consumer of the next split will // not recognize the partial delimiter as a record. // However if using the default delimiter and the next character is a // linefeed then next split will treat it as a delimiter all by itself // and the additional record read should not be performed. if (totalBytesRead == splitLength && inDelimiter && bytesRead > 0) { if (usingCRLF) { needAdditionalRecord = (buffer[0] != '\n'); } else { needAdditionalRecord = true; } } if (bytesRead > 0) { totalBytesRead += bytesRead; } return bytesRead; } @Override public int readLine(Text str, int maxLineLength, int maxBytesToConsume) throws IOException { long bytesRead = 0; if (!finished) { // only allow at most one more record to be read after the stream // reports the split ended if (totalBytesRead > splitLength) { finished = true; } bytesRead = totalBytesRead; int bytesConsumed = super.readLine(str, maxLineLength, maxBytesToConsume); bytesRead = totalBytesRead - bytesRead; // No records left. if (bytesConsumed == 0 && bytesRead == 0) { return 0; } int bufferSize = getBufferSize(); // Add the remaining buffer size not used for the last call // of fillBuffer method. if (lastBytesRead <= 0) { bytesRead += bufferSize; } else if (bytesRead > 0) { bytesRead += bufferSize - lastBytesRead; } // Adjust the size of the buffer not used for this record. // The size is carried over for the next calculation. bytesRead += unusedBytes; unusedBytes = bufferSize - getBufferPosn(); bytesRead -= unusedBytes; } return (int) bytesRead; } @Override public boolean needAdditionalRecordAfterSplit() { return !finished && needAdditionalRecord; } }