/*
* Copyright 2012 Sebastian Annies, Hamburg
*
* 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 com.googlecode.mp4parser.authoring.builder;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.util.ArrayList;
import java.util.List;
/**
* Used to merge adjacent byte buffers.
*/
public class ByteBufferHelper {
public static List<ByteBuffer> mergeAdjacentBuffers(List<ByteBuffer> samples) {
ArrayList<ByteBuffer> nuSamples = new ArrayList<ByteBuffer>(samples.size());
for (ByteBuffer buffer : samples) {
int lastIndex = nuSamples.size() - 1;
if (lastIndex >= 0 && buffer.hasArray() && nuSamples.get(lastIndex).hasArray() && buffer.array() == nuSamples.get(lastIndex).array() &&
nuSamples.get(lastIndex).arrayOffset() + nuSamples.get(lastIndex).limit() == buffer.arrayOffset()) {
ByteBuffer oldBuffer = nuSamples.remove(lastIndex);
ByteBuffer nu = ByteBuffer.wrap(buffer.array(), oldBuffer.arrayOffset(), oldBuffer.limit() + buffer.limit()).slice();
// We need to slice here since wrap([], offset, length) just sets position and not the arrayOffset.
nuSamples.add(nu);
} else if (lastIndex >= 0 &&
buffer instanceof MappedByteBuffer && nuSamples.get(lastIndex) instanceof MappedByteBuffer &&
nuSamples.get(lastIndex).limit() == nuSamples.get(lastIndex).capacity() - buffer.capacity()) {
// This can go wrong - but will it?
ByteBuffer oldBuffer = nuSamples.get(lastIndex);
oldBuffer.limit(buffer.limit() + oldBuffer.limit());
} else {
buffer.rewind();
nuSamples.add(buffer);
}
}
return nuSamples;
}
}