net.derquinse.common.io.ChunkedDirectByteSource.java Source code

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Here is the source code for net.derquinse.common.io.ChunkedDirectByteSource.java

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/*
 * Copyright (C) the original author or authors.
 *
 * 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.derquinse.common.io;

import static com.google.common.base.Preconditions.checkNotNull;
import static net.derquinse.common.io.InternalPreconditions.checkChunkSize;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.List;

import com.google.common.collect.Lists;

/**
 * Direct memory byte source backed by several chunks.
 * @author Andres Rodriguez
 */
final class ChunkedDirectByteSource extends DirectByteSource {
    /** Backing chunks. */
    private final Chunks<SingleDirectByteSource> chunks;

    /**
     * Constructor. The caller must guarantee that the chunks are of the correct type.
     * @param chunks Backing chunks.
     */
    ChunkedDirectByteSource(Chunks<SingleDirectByteSource> chunks) {
        this.chunks = checkNotNull(chunks);
    }

    @Override
    public InputStream openStream() throws IOException {
        return chunks.openStream();
    }

    @Override
    public long size() {
        return chunks.getTotalSize();
    }

    @Override
    public MemoryByteSource merge() {
        final ByteBuffer buffer = ByteBuffer.allocateDirect(chunks.getTotalSize());
        writeTo(buffer);
        buffer.flip();
        return new SingleDirectByteSource(buffer);
    }

    @Override
    public MemoryByteSource merge(int chunkSize) {
        return chunks.merge(this, chunkSize);
    }

    @Override
    public MemoryByteSource toHeap(boolean merge) {
        if (merge) {
            byte[] buffer = new byte[chunks.getTotalSize()];
            writeTo(buffer, 0);
            return new ByteArrayByteSource(buffer);
        } else {
            List<ByteArrayByteSource> list = Lists.newArrayListWithCapacity(chunks.size());
            for (SingleDirectByteSource s : chunks) {
                list.add(s.toHeap(true));
            }
            return new ChunkedHeapByteSource(new Chunks<ByteArrayByteSource>(list));
        }
    }

    @Override
    public MemoryByteSource toHeap(int chunkSize) {
        checkChunkSize(chunkSize);
        if (chunkSize <= chunks.getChunkSize()) {
            return toHeap(false);
        } else if (chunkSize >= chunks.getTotalSize()) {
            return toHeap(true);
        }
        return MemoryByteSourceLoader.get().chunkSize(chunkSize).copy(this);
    }

    @Override
    int writeTo(byte[] buffer, int offset) {
        return chunks.writeTo(buffer, offset);
    }

    @Override
    int writeTo(ByteBuffer buffer) {
        return chunks.writeTo(buffer);
    }

    @Override
    int chunks() {
        return chunks.size();
    }

}