[AD2] Add a helper method to read an arbitrary dict header

import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;

import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.OutputStream;

import java.nio.channels.FileChannel;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Iterator;

        }

        return null;

    }

    /**

     * Convenience method to read the header of a binary file.

     *

     * This is quite resource intensive - don't call when performance is critical.

     *

     * @param file The file to read.

     */

    private static final int HEADER_READING_BUFFER_SIZE = 16384;

    public static FileHeader getDictionaryFileHeader(final File file)

        throws FileNotFoundException, IOException, UnsupportedFormatException {

        final byte[] buffer = new byte[HEADER_READING_BUFFER_SIZE];

        final FileInputStream inStream = new FileInputStream(file);

        try {

            inStream.read(buffer);

            final BinaryDictInputOutput.ByteBufferWrapper wrapper =

                    new BinaryDictInputOutput.ByteBufferWrapper(inStream.getChannel().map(

                            FileChannel.MapMode.READ_ONLY, 0, file.length()));

            return BinaryDictInputOutput.readHeader(wrapper);

        } finally {

            inStream.close();

        }

    }

}