map File to ByteBuffer - Android java.nio

Android examples for java.nio:ByteBuffer

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Description

map File to ByteBuffer

Demo Code

/*//from   www . ja  v a 2s .  c  om
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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.
 */
import com.android.annotations.NonNull;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

public class Main{
    @NonNull
    public static ByteBuffer mapFile(@NonNull File f, long offset,
            @NonNull ByteOrder byteOrder) throws IOException {
        FileInputStream dataFile = new FileInputStream(f);
        try {
            FileChannel fc = dataFile.getChannel();
            MappedByteBuffer buffer = fc.map(FileChannel.MapMode.READ_ONLY,
                    offset, f.length() - offset);
            buffer.order(byteOrder);
            return buffer;
        } finally {
            dataFile.close(); // this *also* closes the associated channel, fc
        }
    }
}

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