ostore.util
Class SHA1Hash

java.lang.Object
  |
  +--ostore.util.SHA1Hash

All Implemented Interfaces:

Cloneable, Comparable, QuickSerializable, SecureHash

Direct Known Subclasses:

SHA1HashKey

public class SHA1Hash

extends Object

implements SecureHash

SHA1Hash is the hash class used by all entities which are SHA1 hashes. (In the prototype, this means Guids and VHashes).

Version:

$Id: SHA1Hash.java,v 1.48 2003/12/22 01:17:10 srhea Exp $

Author:

Chris WElls

Field Summary

protected byte[]	_bytes These are the bytes in this Hash.
static SecureHash	FIRST_HASH This is first hash SHA1
static SecureHash	LAST_HASH This is last hash SHA1
static SHA1Hash	NULL_HASH This is the null hash for SHA1
static byte[]	NULL_HASH_VALUE This is the value of the null hash for SHA1
static int	NUM_BYTES The number of bytes all SHA1Hashs are composed of

Constructor Summary

SHA1Hash()
default constructor (creates null hash)

SHA1Hash(byte[] bytes)
hashes the given buffer to create a new SHA1Hash

SHA1Hash(byte[] bytes, boolean fake)
takes the byte array and just uses it. way to control what your guids look like

SHA1Hash(byte[] bytes, int offset, int len)
hashes the given buffer to create a new SHA1Hash

SHA1Hash(InputBuffer buffer)
Construct out of an input buffer.

SHA1Hash(QuickSerializable d)
hashes over the input object

SHA1Hash(SHA1Hash shash)
copy constructor (creates new hash with value of old hash)

SHA1Hash(SHA1HashBuffer buffer)
Computes and returns the digest of the specified buffer.

SHA1Hash(String s)
hashes over the bytes of the input String

Method Summary

byte[]	bytes() Returns the bytes contained in this hash
Object	clone() Create an exact copy of this hash
int	compareTo(Object o) This routine compares this SHA1Hash to another Object
static void	concatenateHashes(SHA1Hash hash1, SHA1Hash hash2, byte[] buf) This routine concatenates two hashes and stores the result in the input byte array.
boolean	equals(Object other) Compares this SecureHash with another hash, and returns true iff they are the same type of hash and have the same byte representation
String	fullString() Converts all bytes of this SecureHash to a human-readable String
void	hash(byte[] bytes) Hashes over the input bytes
void	hash(byte[] bytes, int offset, int len) Hashes over the input bytes, starting at offset, going for len
void	hash(QuickSerializable o) Hashes over a QuickSerializable object
void	hash(String str) Hashes over the bytes of the input String
int	hashCode() Calculates a Java hash code for this SecureHash object (by taking its lower order bytes)
boolean	isNull() Determines if this SecureHash is a NULL hash or not.
long	lower64bits() Calculates a Java hash code for this SecureHash object (by taking its lower order bytes)
static void	main(String[] args) Measures the speed of various hash implementations.
SecureHash	nullHash() Returns the implementation's NULL hash (typically all zeroes).
void	serialize(OutputBuffer buffer) Add the object to the buffer.
int	size() Return the number of bytes used in the representation of this hash (for example, SHA1 uses 20 bytes)
String	toString() Converts a few bytes of this SecureHash to a human-readable String
boolean	verify(QuickSerializable o) Verifies a QuickSerializable object

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

NUM_BYTES

public static final int NUM_BYTES

The number of bytes all SHA1Hashs are composed of

See Also:

Constant Field Values

NULL_HASH_VALUE

public static final byte[] NULL_HASH_VALUE

This is the value of the null hash for SHA1

FIRST_HASH

public static final SecureHash FIRST_HASH

This is first hash SHA1

LAST_HASH

public static final SecureHash LAST_HASH

This is last hash SHA1

NULL_HASH

public static final SHA1Hash NULL_HASH

This is the null hash for SHA1

_bytes

protected byte[] _bytes

These are the bytes in this Hash.

Constructor Detail

SHA1Hash

public SHA1Hash()

default constructor (creates null hash)

SHA1Hash

public SHA1Hash(SHA1Hash shash)

copy constructor (creates new hash with value of old hash)

Parameters:

shash - == old hash whose value we are to copy

SHA1Hash

public SHA1Hash(byte[] bytes)

hashes the given buffer to create a new SHA1Hash

Parameters:

bytes - the array of bytes over which to hash

SHA1Hash

public SHA1Hash(byte[] bytes,
                boolean fake)

takes the byte array and just uses it. way to control what your guids look like

SHA1Hash

public SHA1Hash(byte[] bytes,
                int offset,
                int len)

hashes the given buffer to create a new SHA1Hash

Parameters:

bytes - the array of bytes over which to hash

offset - in bytes at which to start hashing

len - of bytes over which to hash

SHA1Hash

public SHA1Hash(InputBuffer buffer)

Construct out of an input buffer.

SHA1Hash

public SHA1Hash(String s)

hashes over the bytes of the input String

Parameters:

s - string over which to hash

SHA1Hash

public SHA1Hash(QuickSerializable d)

hashes over the input object

Parameters:

d - object over which to hash

SHA1Hash

public SHA1Hash(SHA1HashBuffer buffer)

Computes and returns the digest of the specified buffer.

Parameters:

buffer - A SecureHashBuffer.

Method Detail

clone

public Object clone()
             throws CloneNotSupportedException

Create an exact copy of this hash

Specified by:

clone in interface SecureHash

Overrides:

clone in class Object

Returns:

new SHA1Hash identical in value to this one

Throws:

CloneNotSupportedException - if clone() is not supported

compareTo

public int compareTo(Object o)
              throws ClassCastException

This routine compares this SHA1Hash to another Object

Specified by:

compareTo in interface Comparable

Parameters:

o - SHA1Hash

Returns:

-1 if this < o, 0 if this == o, or 1 if this > o.

Throws:

ClassCastException - if o is not a SHA1Hash

size

public int size()

Return the number of bytes used in the representation of this hash (for example, SHA1 uses 20 bytes)

Specified by:

size in interface SecureHash

Returns:

number of bytes used in the implementation

isNull

public boolean isNull()

Determines if this SecureHash is a NULL hash or not.

Specified by:

isNull in interface SecureHash

Returns:

true iff this Hash has a NULL value

nullHash

public SecureHash nullHash()

Returns the implementation's NULL hash (typically all zeroes).

Specified by:

nullHash in interface SecureHash

Returns:

the implementation's null hash

bytes

public byte[] bytes()

Returns the bytes contained in this hash

Specified by:

bytes in interface SecureHash

Returns:

the bytes of this hash

equals

public boolean equals(Object other)

Compares this SecureHash with another hash, and returns true iff they are the same type of hash and have the same byte representation

Specified by:

equals in interface SecureHash

Overrides:

equals in class Object

Parameters:

other - the object with which to compare this SecureHash

Returns:

true iff this and o contain the same byte values

hashCode

public int hashCode()

Calculates a Java hash code for this SecureHash object (by taking its lower order bytes)

Specified by:

hashCode in interface SecureHash

Overrides:

hashCode in class Object

Returns:

the Java hash code for this SecureHash

lower64bits

public long lower64bits()

Calculates a Java hash code for this SecureHash object (by taking its lower order bytes)

Returns:

the Java hash code for this SecureHash

hash

public void hash(byte[] bytes,
                 int offset,
                 int len)

Hashes over the input bytes, starting at offset, going for len

Specified by:

hash in interface SecureHash

Parameters:

bytes - array over which to hash

offset - in bytes[] at which to begin hashing

len - of bytes over which to hash

hash

public void hash(byte[] bytes)

Hashes over the input bytes

Specified by:

hash in interface SecureHash

Parameters:

bytes - the byte array over which to hash

hash

public void hash(QuickSerializable o)

Hashes over a QuickSerializable object

Specified by:

hash in interface SecureHash

Parameters:

o - the object over which to hash

hash

public void hash(String str)

Hashes over the bytes of the input String

Specified by:

hash in interface SecureHash

Parameters:

str - the String over which to hash

concatenateHashes

public static void concatenateHashes(SHA1Hash hash1,
                                     SHA1Hash hash2,
                                     byte[] buf)

This routine concatenates two hashes and stores the result in the input byte array.

Parameters:

hash1 - the first hash to concatenate

hash2 - the second hash to concatenate

buf - the byte array in which to storet the concatenation

verify

public boolean verify(QuickSerializable o)

Verifies a QuickSerializable object

Specified by:

verify in interface SecureHash

Parameters:

o - the object over which to hash

Returns:

true iff the input object hashes to a hash value equal to this hash value

toString

public String toString()

Converts a few bytes of this SecureHash to a human-readable String

Specified by:

toString in interface SecureHash

Overrides:

toString in class Object

Returns:

human-readable String representation of this Hash

fullString

public String fullString()

Converts all bytes of this SecureHash to a human-readable String

Specified by:

fullString in interface SecureHash

Returns:

human-readable String representation of this Hash containing every nibble of this Hash's value

serialize

public void serialize(OutputBuffer buffer)

Description copied from interface: QuickSerializable

Add the object to the buffer.

Specified by:

serialize in interface QuickSerializable

Parameters:

buffer - the output buffer to add the object to

main

public static void main(String[] args)

Measures the speed of various hash implementations.