XrdEc::RedundancyProvider Class Reference

#include <XrdEcRedundancyProvider.hh>

Collaboration diagram for XrdEc::RedundancyProvider:

Classes
struct	CodingTable

Public Member Functions
void	compute (stripes_t &stripes)
	RedundancyProvider (const ObjCfg &objcfg)

Private Member Functions
std::string	getErrorPattern (stripes_t &stripes) const
CodingTable &	getCodingTable (const std::string &pattern)
void	replication (stripes_t &stripes)

Private Attributes
ObjCfg	objcfg
std::vector< unsigned char >	encode_matrix
	the encoding matrix, required to compute any decode matrix
std::unordered_map< std::string, CodingTable >	cache
	a cache of previously used coding tables
std::mutex	mutex
	concurrency control

Detailed Description

The redundancy provider class offers automatic parity computing and data recovery. Depending on configuration it will use erasure coding or replication.

Constructor & Destructor Documentation

RedundancyProvider()

XrdEc::RedundancyProvider::RedundancyProvider

(

const ObjCfg &

objcfg

)

Constructor. Stripe parameters (number of data and parity blocks) are constant per ErasureEncoding object.

Member Function Documentation

compute()

void XrdEc::RedundancyProvider::compute

(

stripes_t &

stripes

)

Compute all missing data and parity blocks in the the stripe. Stripe size has to equal nData+nParity. Blocks can be arbitrary size, but size has to be equal within a stripe. Function will throw on incorrect input.

Parameters

stripes

nData+nParity blocks, missing (empty) blocks will be computed if possible.

Referenced by XrdEc::WrtBuff::Encode().

getCodingTable()

CodingTable & XrdEc::RedundancyProvider::getCodingTable ( const std::string &  pattern )

private

Returns a reference to the coding table for the requested error pattern, if possible from the cache. If that particular table has not been requested before, it will be constructed.

Parameters

pattern

error pattern / signature

Returns

reference to the coding table for the supplied error pattern

getErrorPattern()

std::string XrdEc::RedundancyProvider::getErrorPattern ( stripes_t &  stripes ) const

private

Constructs a string of the error pattern / signature. Each missing block in the stripe is counted as an error block, existing blocks are assumed to be correct (crc integrity checks of blocks should be done previously to attempting erasure decoding).

Parameters

stripes

vector of nData+nParity blocks, missing (empty) blocks are errors

Returns

a string of stripe size describing the error pattern

replication()

void XrdEc::RedundancyProvider::replication ( stripes_t &  stripes )

private

Member Data Documentation

cache

std::unordered_map<std::string, CodingTable> XrdEc::RedundancyProvider::cache

private

a cache of previously used coding tables

encode_matrix

std::vector<unsigned char> XrdEc::RedundancyProvider::encode_matrix

private

the encoding matrix, required to compute any decode matrix

mutex

std::mutex XrdEc::RedundancyProvider::mutex

private

concurrency control

objcfg

ObjCfg XrdEc::RedundancyProvider::objcfg

private

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The documentation for this class was generated from the following file:

• XrdEcRedundancyProvider.hh