Package net.i2p.data

Class Hash

java.lang.Object

net.i2p.data.SimpleDataStructure

net.i2p.data.Hash

All Implemented Interfaces:

DataStructure

Direct Known Subclasses:

LocalHash, Peer

public class Hash
extends SimpleDataStructure

Defines the hash as defined by the I2P data structure spec. A hash is the SHA-256 of some data, taking up 32 bytes.

Author:

jrandom

Field Summary

Fields

Modifier and Type	Field	Description
static final Hash	FAKE_HASH
static final int	HASH_LENGTH

Fields inherited from class net.i2p.data.SimpleDataStructure

_data

Constructor Summary

Constructors

Constructor	Description
Hash()
Hash(byte[] data)

Method Summary

Modifier and Type	Method	Description
static void	clearCache()
static Hash	create(byte[] data)	Pull from cache or return new WARNING - If the SDS is found in the cache, the passed-in byte array will be returned to the SimpleByteCache for reuse.
static Hash	create(byte[] data, int off)	Pull from cache or return new
static Hash	create(InputStream in)	Pull from cache or return new
int	hashCode()	a Hash is a hash, so just use the first 4 bytes for speed
int	length()	The legal length of the byte array in this data structure
void	readBytes(InputStream in)	Sets the data.
void	setData(byte[] data)	Sets the data.
String	toBase32()	For convenience.
String	toBase64()	render the structure into modified base 64 notation

Methods inherited from class net.i2p.data.SimpleDataStructure

calculateHash, equals, fromBase64, fromByteArray, getData, read, toByteArray, toString, writeBytes

Methods inherited from class java.lang.Object

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

Field Details

HASH_LENGTH

public static final int HASH_LENGTH

See Also:

• Constant Field Values

FAKE_HASH

public static final Hash FAKE_HASH

Constructor Details

Hash

public Hash()

Hash

public Hash(byte[] data)

Throws:

IllegalArgumentException - if data is not 32 bytes (null is ok)

Method Details

create

public static Hash create(byte[] data)

Pull from cache or return new WARNING - If the SDS is found in the cache, the passed-in byte array will be returned to the SimpleByteCache for reuse. Do NOT save a reference to the passed-in data, or use or modify it, after this call. Ignore this warning and you WILL corrupt the cache or other data structures.

Throws:

IllegalArgumentException - if data is not the correct number of bytes

Since:

0.8.3

create

public static Hash create(byte[] data,
 int off)

Pull from cache or return new

Throws:

ArrayIndexOutOfBoundsException - if not enough bytes

Since:

0.8.3

create

public static Hash create(InputStream in)
                   throws IOException

Pull from cache or return new

Throws:

IOException

Since:

0.8.3

length

public int length()

Description copied from class: SimpleDataStructure

The legal length of the byte array in this data structure

Specified by:

length in class SimpleDataStructure

setData

public void setData(byte[] data)

Description copied from class: SimpleDataStructure

Sets the data.

Overrides:

setData in class SimpleDataStructure

Parameters:

data - of correct length, or null

Throws:

IllegalArgumentException - if data is not 32 bytes (null is ok)

readBytes

public void readBytes(InputStream in)
               throws DataFormatException,
IOException

Description copied from class: SimpleDataStructure

Sets the data.

Specified by:

readBytes in interface DataStructure

Overrides:

readBytes in class SimpleDataStructure

Parameters:

in - the stream to read

Throws:

DataFormatException - if the data is improperly formatted

IOException - if there was a problem reading the stream

hashCode

public int hashCode()

a Hash is a hash, so just use the first 4 bytes for speed

Overrides:

hashCode in class SimpleDataStructure

toBase64

public String toBase64()

Description copied from interface: DataStructure

render the structure into modified base 64 notation

Specified by:

toBase64 in interface DataStructure

Overrides:

toBase64 in class SimpleDataStructure

Returns:

null on error

toBase32

public String toBase32()

For convenience.

Returns:

"{52 chars}.b32.i2p" or null if data not set.

Since:

0.9.25

clearCache

public static void clearCache()

Since:

0.9.17