/*
* Copyright 2010 Google Inc.
*
* Licensed 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 com.google.appengine.tools.mapreduce.inputs;
import com.google.common.io.CountingInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.NoSuchElementException;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A reader to return one line at a time from an underlying input stream.
*
* For internal use only. User code cannot safely depend on this class.
*
*/
class LineInputStream {
private static final Logger log = Logger.getLogger(LineInputStream.class.getName());
private static final int INITIAL_BUFFER_SIZE = 10000;
private final int separator;
private final CountingInputStream in;
private final long lengthToRead;
LineInputStream(InputStream in, long lengthToRead, byte separator) {
this.in = new CountingInputStream(in);
this.lengthToRead = lengthToRead;
this.separator = (separator & 0xff);
}
public byte[] next() {
try {
// we are reading one record after lengthToRead because the splits are not assumed to be
// aligned to separators in the file.
long recordStart = in.getCount();
if (recordStart - 1 >= lengthToRead) {
throw new NoSuchElementException();
}
ByteArrayOutputStream tempBuffer = new ByteArrayOutputStream(INITIAL_BUFFER_SIZE);
copyUntilNextRecord(tempBuffer);
return tempBuffer.toByteArray();
} catch (IOException e) {
log.log(Level.WARNING, "Failed to read next record", e);
throw new RuntimeException("Failed to read next record", e);
}
}
public long getBytesCount() {
return in.getCount();
}
private void copyUntilNextRecord(OutputStream out) throws IOException {
int value = in.read();
if (value == -1) {
throw new NoSuchElementException();
}
while (value != separator && value != -1) {
out.write(value);
value = in.read();
}
}
public void close() throws IOException {
in.close();
}
}