Merge "Add FileUtils.checksumCrc32" into honeycomb-LTE

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.util.regex.Pattern;

import java.util.zip.CRC32;

import java.util.zip.CheckedInputStream;

/**

 * Tools for managing files.  Not for public consumption.

 * @hide

 */

public class FileUtils

{

public class FileUtils {

    public static final int S_IRWXU = 00700;

    public static final int S_IRUSR = 00400;

    public static final int S_IWUSR = 00200;

    /** returns the FAT file system volume ID for the volume mounted 

     * at the given mount point, or -1 for failure

     * @param mount point for FAT volume

     * @param mountPoint point for FAT volume

     * @return volume ID or -1

     */

    public static native int getFatVolumeId(String mountPoint);

            input.close();

        }

    }

    /**

     * Computes the checksum of a file using the CRC32 checksum routine.

     * The value of the checksum is returned.

     *

     * @param file  the file to checksum, must not be null

     * @return the checksum value or an exception is thrown.

     */

    public static long checksumCrc32(File file) throws FileNotFoundException, IOException {

        CRC32 checkSummer = new CRC32();

        CheckedInputStream cis = null;

        try {

            cis = new CheckedInputStream( new FileInputStream(file), checkSummer);

            byte[] buf = new byte[128];

            while(cis.read(buf) >= 0) {

                // Just read for checksum to get calculated.

            }

            return checkSummer.getValue();

        } finally {

            if (cis != null) {

                try {

                    cis.close();

                } catch (IOException e) {

                }

            }

        }

    }

}