/*
* 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.beam.sdk.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
/**
* Utility functions for stream operations.
*/
public class StreamUtils {
private StreamUtils() {
}
private static final int BUF_SIZE = 8192;
private static ThreadLocal<SoftReference<byte[]>> threadLocalBuffer = new ThreadLocal<>();
/**
* Efficient converting stream to bytes.
*/
public static byte[] getBytes(InputStream stream) throws IOException {
if (stream instanceof ExposedByteArrayInputStream) {
// Fast path for the exposed version.
return ((ExposedByteArrayInputStream) stream).readAll();
} else if (stream instanceof ByteArrayInputStream) {
// Fast path for ByteArrayInputStream.
byte[] ret = new byte[stream.available()];
stream.read(ret);
return ret;
}
// Falls back to normal stream copying.
SoftReference<byte[]> refBuffer = threadLocalBuffer.get();
byte[] buffer = refBuffer == null ? null : refBuffer.get();
if (buffer == null) {
buffer = new byte[BUF_SIZE];
threadLocalBuffer.set(new SoftReference<byte[]>(buffer));
}
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
while (true) {
int r = stream.read(buffer);
if (r == -1) {
break;
}
outStream.write(buffer, 0, r);
}
return outStream.toByteArray();
}
}