Package com.pnfsoftware.jeb.util.encoding

Class Hash

java.lang.Object

com.pnfsoftware.jeb.util.encoding.Hash

public class Hash
extends Object

Hash calculation routines. To calculate multiple hashes in a more efficient way, use HashCalculator instead.

Constructor Summary

Constructors

Constructor	Description
Hash()

Method Summary

Modifier and Type	Method	Description
static int	calculateCRC32(byte[] data)	Compute a CRC-32 checksum for a byte array.
static byte[]	calculateMD5(byte[] data)	Compute an MD5 digest for a byte array.
static byte[]	calculateSHA1(byte[] data)	Compute a SHA-1 digest for a byte array.
static byte[]	calculateSHA256(byte[] data)	Compute a SHA-256 digest for a byte array.
static void	checksumBlockFileUpdate(Checksum h, File f)	Update a checksum with all bytes of a file.
static void	checksumBlockFileUpdate(Checksum h, File f, long offset, long size)	Update a checksum with a byte range of a file.
static void	checksumBlockFileUpdate(Checksum h, RandomAccessFile raf, long size)	Update a checksum with bytes read from the current position of a random-access file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Hash

public Hash()

Method Details

calculateCRC32

public static int calculateCRC32(byte[] data)

Compute a CRC-32 checksum for a byte array.

Parameters:

data - input bytes

Returns:

CRC-32 value, truncated to an int

calculateMD5

public static byte[] calculateMD5(byte[] data)

Compute an MD5 digest for a byte array.

Parameters:

data - input bytes

Returns:

16-byte MD5 digest

calculateSHA1

public static byte[] calculateSHA1(byte[] data)

Compute a SHA-1 digest for a byte array.

Parameters:

data - input bytes

Returns:

20-byte SHA-1 digest

calculateSHA256

public static byte[] calculateSHA256(byte[] data)

Compute a SHA-256 digest for a byte array.

Parameters:

data - input bytes

Returns:

32-byte SHA-256 digest

checksumBlockFileUpdate

public static void checksumBlockFileUpdate(Checksum h,
 File f)
                                    throws IOException

Update a checksum with all bytes of a file.

Parameters:

h - checksum to update

f - input file

Throws:

IOException - if the file cannot be read

checksumBlockFileUpdate

public static void checksumBlockFileUpdate(Checksum h,
 File f,
 long offset,
 long size)
                                    throws IOException

Update a checksum with a byte range of a file.

Parameters:

h - checksum to update

f - input file

offset - start offset in the file

size - number of bytes to read

Throws:

IOException - if the file range cannot be read

checksumBlockFileUpdate

public static void checksumBlockFileUpdate(Checksum h,
 RandomAccessFile raf,
 long size)
                                    throws IOException

Update a checksum with bytes read from the current position of a random-access file.

Parameters:

h - checksum to update

raf - input file, positioned at the start of the range

size - number of bytes to read

Throws:

IOException - if the requested byte range cannot be read