Package io.odilon.rs

Class ReedSolomon

java.lang.Object

io.odilon.rs.ReedSolomon

public class ReedSolomon
extends Object

Reed-Solomon Coding over 8-bit values.

Constructor Summary

Constructors

Constructor	Description
ReedSolomon(int dataShardCount, int parityShardCount)	Initializes a new encoder/decoder.

Method Summary

Modifier and Type	Method	Description
void	decodeMissing(byte[][] shards, boolean[] shardPresent, int offset, int byteCount)	Given a list of shards, some of which contain data, fills in the ones that don't have data.
void	encodeParity(byte[][] shards, int offset, int byteCount)	Encodes parity for a set of data shards.
int	getDataShardCount()	Returns the number of data shards.
int	getParityShardCount()	Returns the number of parity shards.
int	getTotalShardCount()	Returns the total number of shards.
boolean	isParityCorrect(byte[][] shards, int firstByte, int byteCount)	Returns true if the parity shards contain the right data.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReedSolomon

public ReedSolomon(int dataShardCount,
                   int parityShardCount)

Initializes a new encoder/decoder.

Method Detail

getDataShardCount

public int getDataShardCount()

Returns the number of data shards.

getParityShardCount

public int getParityShardCount()

Returns the number of parity shards.

getTotalShardCount

public int getTotalShardCount()

Returns the total number of shards.

encodeParity

public void encodeParity(byte[][] shards,
                         int offset,
                         int byteCount)

Encodes parity for a set of data shards.

Parameters:

shards - An array containing data shards followed by parity shards. Each shard is a byte array, and they must all be the same size.

offset - The index of the first byte in each shard to encode.

byteCount - The number of bytes to encode in each shard.

isParityCorrect

public boolean isParityCorrect(byte[][] shards,
                               int firstByte,
                               int byteCount)

Returns true if the parity shards contain the right data.

Parameters:

shards - An array containing data shards followed by parity shards. Each shard is a byte array, and they must all be the same size.

firstByte - The index of the first byte in each shard to check.

byteCount - The number of bytes to check in each shard.

decodeMissing

public void decodeMissing(byte[][] shards,
                          boolean[] shardPresent,
                          int offset,
                          int byteCount)

Given a list of shards, some of which contain data, fills in the ones that don't have data. Quickly does nothing if all of the shards are present. If any shards are missing (based on the flags in shardsPresent), the data in those shards is recomputed and filled in.