net.bytebuddy.utility.StreamDrainer Maven / Gradle / Ivy
/*
* Copyright 2014 - Present Rafael Winterhalter
*
* 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 net.bytebuddy.utility;
import net.bytebuddy.build.HashCodeAndEqualsPlugin;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
/**
* A utility for draining the contents of an {@link java.io.InputStream} into a {@code byte} array.
*/
@HashCodeAndEqualsPlugin.Enhance
public class StreamDrainer {
/**
* The default size of the buffer for draining a stream.
*/
public static final int DEFAULT_BUFFER_SIZE = 1024;
/**
* A default instance using the {@link StreamDrainer#DEFAULT_BUFFER_SIZE}.
*/
public static final StreamDrainer DEFAULT = new StreamDrainer();
/**
* A convenience constant referring to the value representing the end of a stream.
*/
private static final int END_OF_STREAM = -1;
/**
* A convenience constant referring to the value representing the start of a stream.
*/
private static final int FROM_BEGINNING = 0;
/**
* The buffer size for reading from a given stream.
*/
private final int bufferSize;
/**
* Creates a stream drainer with the default buffer size.
*/
public StreamDrainer() {
this(DEFAULT_BUFFER_SIZE);
}
/**
* Creates a stream drainer with the given buffer size.
*
* @param bufferSize The buffer size for reading from a given stream.
*/
public StreamDrainer(int bufferSize) {
this.bufferSize = bufferSize;
}
/**
* Drains an input stream into a byte array. The given input stream is not closed.
*
* @param inputStream The input stream to drain.
* @return A byte array containing the content of the input stream.
* @throws IOException If the stream reading causes an error.
*/
public byte[] drain(InputStream inputStream) throws IOException {
List previousBytes = new ArrayList();
byte[] currentArray = new byte[bufferSize];
int currentIndex = 0;
int currentRead;
do {
currentRead = inputStream.read(currentArray, currentIndex, bufferSize - currentIndex);
currentIndex += Math.max(currentRead, 0);
if (currentIndex == bufferSize) {
previousBytes.add(currentArray);
currentArray = new byte[bufferSize];
currentIndex = 0;
}
} while (currentRead != END_OF_STREAM);
byte[] result = new byte[previousBytes.size() * bufferSize + currentIndex];
int arrayIndex = 0;
for (byte[] previousByte : previousBytes) {
System.arraycopy(previousByte, FROM_BEGINNING, result, arrayIndex++ * bufferSize, bufferSize);
}
System.arraycopy(currentArray, FROM_BEGINNING, result, arrayIndex * bufferSize, currentIndex);
return result;
}
}