org.apache.poi.util.IOUtils 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.poi.util;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public final class IOUtils {
private IOUtils() {
// no instances of this class
}
/**
* Reads all the data from the input stream, and returns the bytes read.
*/
public static byte[] toByteArray(InputStream stream) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[4096];
int read = 0;
while (read != -1) {
read = stream.read(buffer);
if (read > 0) {
baos.write(buffer, 0, read);
}
}
return baos.toByteArray();
}
/**
* Helper method, just calls readFully(in, b, 0, b.length)
*/
public static int readFully(InputStream in, byte[] b) throws IOException {
return readFully(in, b, 0, b.length);
}
/**
* Same as the normal in.read(b, off, len), but tries to ensure
* that the entire len number of bytes is read.
*
* If the end of file is reached before any bytes are read, returns -1. If
* the end of the file is reached after some bytes are read, returns the
* number of bytes read. If the end of the file isn't reached before len
* bytes have been read, will return len bytes.
*/
public static int readFully(InputStream in, byte[] b, int off, int len) throws IOException {
int total = 0;
while (true) {
int got = in.read(b, off + total, len - total);
if (got < 0) {
return (total == 0) ? -1 : total;
}
total += got;
if (total == len) {
return total;
}
}
}
/**
* Copies all the data from the given InputStream to the OutputStream. It
* leaves both streams open, so you will still need to close them once done.
*/
public static void copy(InputStream inp, OutputStream out) throws IOException {
byte[] buff = new byte[4096];
int count;
while ((count = inp.read(buff)) != -1) {
if (count > 0) {
out.write(buff, 0, count);
}
}
}
}