XRootD
XrdEc::RedundancyProvider Class Reference

#include <XrdEcRedundancyProvider.hh>

+ Collaboration diagram for XrdEc::RedundancyProvider:

Public Member Functions

 RedundancyProvider (const ObjCfg &objcfg)
 
void compute (stripes_t &stripes)
 

Detailed Description

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

Definition at line 41 of file XrdEcRedundancyProvider.hh.

Constructor & Destructor Documentation

◆ RedundancyProvider()

XrdEc::RedundancyProvider::RedundancyProvider ( const ObjCfg objcfg)

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

Definition at line 150 of file XrdEcRedundancyProvider.cc.

150  :
151  objcfg( objcfg ),
152  encode_matrix( objcfg.nbchunks * objcfg.nbdata )
153 {
154  // k = data
155  // m = data + parity
156  gf_gen_cauchy1_matrix( encode_matrix.data(), static_cast<int>( objcfg.nbchunks ), static_cast<int>( objcfg.nbdata ) );
157 }
const uint8_t nbdata
Definition: XrdEcObjCfg.hh:87
const uint8_t nbchunks
Definition: XrdEcObjCfg.hh:85

References XrdEc::ObjCfg::nbchunks, and XrdEc::ObjCfg::nbdata.

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

Definition at line 228 of file XrdEcRedundancyProvider.cc.

229 {
230  /* throws if stripe is not recoverable */
231  std::string pattern = getErrorPattern( stripes );
232 
233  /* nothing to do if there are no parity blocks. */
234  if ( !objcfg.nbparity ) return;
235 
236  /* in case of a single data block use replication */
237  if ( objcfg.nbdata == 1 )
238  return replication( stripes );
239 
240  /* normal operation: erasure coding */
241  CodingTable& dd = getCodingTable(pattern);
242 
243  unsigned char* inbuf[objcfg.nbdata];
244  for( uint8_t i = 0; i < objcfg.nbdata; i++ )
245  inbuf[i] = reinterpret_cast<unsigned char*>( stripes[dd.blockIndices[i]].buffer );
246 
247  std::vector<unsigned char> memory( dd.nErrors * objcfg.chunksize );
248 
249  unsigned char* outbuf[dd.nErrors];
250  for (int i = 0; i < dd.nErrors; i++)
251  {
252  outbuf[i] = &memory[i * objcfg.chunksize];
253  }
254 
255  ec_encode_data(
256  static_cast<int>( objcfg.chunksize ), // Length of each block of data (vector) of source or destination data.
257  static_cast<int>( objcfg.nbdata ), // The number of vector sources in the generator matrix for coding.
258  dd.nErrors, // The number of output vectors to concurrently encode/decode.
259  dd.table.data(), // Pointer to array of input tables
260  inbuf, // Array of pointers to source input buffers
261  outbuf // Array of pointers to coded output buffers
262  );
263 
264  int e = 0;
265  for (size_t i = 0; i < objcfg.nbchunks; i++)
266  {
267  if( pattern[i] )
268  {
269  memcpy( stripes[i].buffer, outbuf[e], objcfg.chunksize );
270  e++;
271  }
272  }
273 }
const uint8_t nbparity
Definition: XrdEcObjCfg.hh:86
const uint64_t chunksize
Definition: XrdEcObjCfg.hh:89

References XrdEc::ObjCfg::chunksize, XrdEc::ObjCfg::nbchunks, XrdEc::ObjCfg::nbdata, and XrdEc::ObjCfg::nbparity.

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

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