org.apache.commons.io.input.WindowsLineEndingInputStream Maven / Gradle / Ivy
/*
* 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.commons.io.input;
import java.io.IOException;
import java.io.InputStream;
/**
* A filtering input stream that ensures the content will have windows line endings, CRLF.
*
* @since 2.5
*/
public class WindowsLineEndingInputStream extends InputStream {
private boolean slashRSeen = false;
private boolean slashNSeen = false;
private boolean injectSlashN = false;
private boolean eofSeen = false;
private final InputStream target;
private final boolean ensureLineFeedAtEndOfFile;
/**
* Create an input stream that filters another stream
*
* @param in The input stream to wrap
* @param ensureLineFeedAtEndOfFile true to ensure that the file ends with CRLF
*/
public WindowsLineEndingInputStream( final InputStream in, final boolean ensureLineFeedAtEndOfFile ) {
this.target = in;
this.ensureLineFeedAtEndOfFile = ensureLineFeedAtEndOfFile;
}
/**
* Reads the next item from the target, updating internal flags in the process
* @return the next int read from the target stream
* @throws IOException upon error
*/
private int readWithUpdate() throws IOException {
final int target = this.target.read();
eofSeen = target == -1;
if ( eofSeen ) {
return target;
}
slashRSeen = target == '\r';
slashNSeen = target == '\n';
return target;
}
/**
* {@inheritDoc}
*/
@Override
public int read() throws IOException {
if ( eofSeen ) {
return eofGame();
} else if ( injectSlashN ) {
injectSlashN = false;
return '\n';
} else {
final boolean prevWasSlashR = slashRSeen;
final int target = readWithUpdate();
if ( eofSeen ) {
return eofGame();
}
if ( target == '\n' ) {
if ( !prevWasSlashR )
{
injectSlashN = true;
return '\r';
}
}
return target;
}
}
/**
* Handles the eof-handling at the end of the stream
* @return The next char to output to the stream
*/
private int eofGame() {
if ( !ensureLineFeedAtEndOfFile ) {
return -1;
}
if ( !slashNSeen && !slashRSeen ) {
slashRSeen = true;
return '\r';
}
if ( !slashNSeen ) {
slashRSeen = false;
slashNSeen = true;
return '\n';
}
return -1;
}
/**
* Closes the stream. Also closes the underlying stream.
* @throws IOException upon error
*/
@Override
public void close() throws IOException {
super.close();
target.close();
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void mark( final int readlimit ) {
throw new UnsupportedOperationException( "Mark not supported" );
}
}