/*
* 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;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
/**
* General IO stream manipulation utilities.
* <p>
* This class provides static utility methods for input/output operations.
* <ul>
* <li>closeQuietly - these methods close a stream ignoring nulls and exceptions
* <li>toXxx/read - these methods read data from a stream
* <li>write - these methods write data to a stream
* <li>copy - these methods copy all the data from one stream to another
* <li>contentEquals - these methods compare the content of two streams
* </ul>
* <p>
* The byte-to-char methods and char-to-byte methods involve a conversion step.
* Two methods are provided in each case, one that uses the platform default
* encoding and the other which allows you to specify an encoding. You are
* encouraged to always specify an encoding because relying on the platform
* default can lead to unexpected results, for example when moving from
* development to production.
* <p>
* All the methods in this class that read a stream are buffered internally.
* This means that there is no cause to use a <code>BufferedInputStream</code>
* or <code>BufferedReader</code>. The default buffer size of 4K has been shown
* to be efficient in tests.
* <p>
* Wherever possible, the methods in this class do <em>not</em> flush or close
* the stream. This is to avoid making non-portable assumptions about the
* streams' origin and further use. Thus the caller is still responsible for
* closing streams after use.
* <p>
* Origin of code: Excalibur.
*
* @author Peter Donald
* @author Jeff Turner
* @author Matthew Hawthorne
* @author Stephen Colebourne
* @author Gareth Davis
* @author Ian Springer
* @author Niall Pemberton
* @author Sandy McArthur
* @version $Id: IOUtils.java 481854 2006-12-03 18:30:07Z scolebourne $
*/
public class IOUtils {
// NOTE: This class is focussed on InputStream, OutputStream, Reader and
// Writer. Each method should take at least one of these as a parameter,
// or return one of them.
/**
* The Unix directory separator character.
*/
public static final char DIR_SEPARATOR_UNIX = '/';
/**
* The Windows directory separator character.
*/
public static final char DIR_SEPARATOR_WINDOWS = '\\';
/**
* The system directory separator character.
*/
public static final char DIR_SEPARATOR = File.separatorChar;
/**
* The Unix line separator string.
*/
public static final String LINE_SEPARATOR_UNIX = "\n";
/**
* The Windows line separator string.
*/
public static final String LINE_SEPARATOR_WINDOWS = "\r\n";
/**
* The system line separator string.
*/
public static final String LINE_SEPARATOR;
static {
// avoid security issues
StringWriter buf = new StringWriter(4);
PrintWriter out = new PrintWriter(buf);
out.println();
LINE_SEPARATOR = buf.toString();
}
/**
* The default buffer size to use.
*/
private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
/**
* Instances should NOT be constructed in standard programming.
*/
public IOUtils() {
super();
}
// copy from InputStream
// -----------------------------------------------------------------------
/**
* Copy bytes from an <code>InputStream</code> to an
* <code>OutputStream</code>.
* <p>
* This method buffers the input internally, so there is no need to use a
* <code>BufferedInputStream</code>.
* <p>
* Large streams (over 2GB) will return a bytes copied value of
* <code>-1</code> after the copy has completed since the correct number of
* bytes cannot be returned as an int. For large streams use the
* <code>copyLarge(InputStream, OutputStream)</code> method.
*
* @param input
* the <code>InputStream</code> to read from
* @param output
* the <code>OutputStream</code> to write to
* @return the number of bytes copied
* @throws NullPointerException
* if the input or output is null
* @throws IOException
* if an I/O error occurs
* @throws ArithmeticException
* if the byte count is too large
* @since Commons IO 1.1
*/
public static int copy(final InputStream input, final OutputStream output)
throws IOException {
long count = copyLarge(input, output);
if (count > Integer.MAX_VALUE) {
return -1;
}
return (int) count;
}
/**
* Copy bytes from a large (over 2GB) <code>InputStream</code> to an
* <code>OutputStream</code>.
* <p>
* This method buffers the input internally, so there is no need to use a
* <code>BufferedInputStream</code>.
*
* @param input
* the <code>InputStream</code> to read from
* @param output
* the <code>OutputStream</code> to write to
* @return the number of bytes copied
* @throws NullPointerException
* if the input or output is null
* @throws IOException
* if an I/O error occurs
* @since Commons IO 1.3
*/
public static long copyLarge(final InputStream input,
final OutputStream output) throws IOException {
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
long count = 0;
int n = 0;
while (-1 != (n = input.read(buffer))) {
output.write(buffer, 0, n);
count += n;
}
return count;
}
/**
* Unconditionally close an <code>InputStream</code>.
* <p>
* Equivalent to {@link InputStream#close()}, except any exceptions will be ignored.
* This is typically used in finally blocks.
*
* @param input the InputStream to close, may be null or already closed
*/
public static void closeQuietly(InputStream input) {
try {
if (input != null) {
input.close();
}
} catch (IOException ioe) {
// ignore
}
}
/**
* Unconditionally close an <code>OutputStream</code>.
* <p>
* Equivalent to {@link OutputStream#close()}, except any exceptions will be ignored.
* This is typically used in finally blocks.
*
* @param output the OutputStream to close, may be null or already closed
*/
public static void closeQuietly(OutputStream output) {
try {
if (output != null) {
output.close();
}
} catch (IOException ioe) {
// ignore
}
}
}
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