CyclicHash

java.lang.Object
- au.notzed.dez.CyclicHash

```
public class CyclicHash
extends java.lang.Object
```
Cyclic polynomial rolling hash.
This implements a rolling hash of a fixed length.
Input bytes are hashed using a random table. The randomness affects the quality of the hash.

Constructor Summary

Constructors
Constructor Description

CyclicHash(int length)
Creates a cyclic hash.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`init(byte[] data, int off)`	Initialises the hash.
`int`	`update(byte leave, byte enter)`	Updates the hash incrementally.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CyclicHash
```
public CyclicHash(int length)
```
    Creates a cyclic hash.
    
    Parameters:
    
    length - The block length for the hash.
- Method Detail
  - init
```
public int init(byte[] data,
                int off)
```
    Initialises the hash.
    This will hash one block of data at the given location.
    
    Parameters:
    
    data - Data buffer.
    
    off - Offset into data.
    
    Returns:
    
    The hash code of this block.
    
    Throws:
    
    java.lang.ArrayIndexOutOfBoundsException - If the buffer is too short.
  - update
```
public int update(byte leave,
                  byte enter)
```
    Updates the hash incrementally.
    Advance the hash by one location.
    
    Parameters:
    
    leave - the byte leaving. Must match the oldest byte included in the hash value.
    
    enter - the byte entering.
    
    Returns:
    
    The hash code for the last block-size bytes.