X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fsrc%2Ferasure-code%2Fshec%2FErasureCodeShec.cc;fp=src%2Fceph%2Fsrc%2Ferasure-code%2Fshec%2FErasureCodeShec.cc;h=0000000000000000000000000000000000000000;hb=7da45d65be36d36b880cc55c5036e96c24b53f00;hp=17b380d5e43b2d0039393e6e56b3b80f5ac7a88c;hpb=691462d09d0987b47e112d6ee8740375df3c51b2;p=stor4nfv.git

diff --git a/src/ceph/src/erasure-code/shec/ErasureCodeShec.cc b/src/ceph/src/erasure-code/shec/ErasureCodeShec.cc
deleted file mode 100644
index 17b380d..0000000
--- a/src/ceph/src/erasure-code/shec/ErasureCodeShec.cc
+++ /dev/null
@@ -1,806 +0,0 @@
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-// vim: ts=8 sw=2 smarttab
-/*
- * Ceph - scalable distributed file system
- *
- * Copyright (C) 2014 FUJITSU LIMITED
- * Copyright (C) 2013,2014 Cloudwatt <libre.licensing@cloudwatt.com>
- * Copyright (C) 2014 Red Hat <contact@redhat.com>
- *
- * Author: Takanori Nakao <nakao.takanori@jp.fujitsu.com>
- * Author: Takeshi Miyamae <miyamae.takeshi@jp.fujitsu.com>
- * Author: Loic Dachary <loic@dachary.org>
- *
- *  This library is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU Lesser General Public
- *  License as published by the Free Software Foundation; either
- *  version 2.1 of the License, or (at your option) any later version.
- *
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <algorithm>
-using namespace std;
-
-#include "common/debug.h"
-#include "ErasureCodeShec.h"
-extern "C" {
-#include "jerasure/include/jerasure.h"
-#include "jerasure/include/galois.h"
-
-extern int calc_determinant(int *matrix, int dim);
-extern int* reed_sol_vandermonde_coding_matrix(int k, int m, int w);
-}
-
-#define dout_context g_ceph_context
-#define dout_subsys ceph_subsys_osd
-#undef dout_prefix
-#define dout_prefix _prefix(_dout)
-
-static ostream& _prefix(std::ostream* _dout)
-{
-  return *_dout << "ErasureCodeShec: ";
-}
-
-int ErasureCodeShec::init(ErasureCodeProfile &profile,
-			  ostream *ss)
-{
-  int err = 0;
-  err |= parse(profile);
-  if (err)
-    return err;
-  prepare();
-  return ErasureCode::init(profile, ss);
-}
-
-unsigned int ErasureCodeShec::get_chunk_size(unsigned int object_size) const
-{
-  unsigned alignment = get_alignment();
-  unsigned tail = object_size % alignment;
-  unsigned padded_length = object_size + ( tail ?  ( alignment - tail ) : 0 );
-
-  assert(padded_length % k == 0);
-  return padded_length / k;
-}
-
-int ErasureCodeShec::minimum_to_decode(const set<int> &want_to_read,
-				       const set<int> &available_chunks,
-				       set<int> *minimum_chunks)
-{
-  if (!minimum_chunks) return -EINVAL;
-
-  for (set<int>::iterator it = available_chunks.begin(); it != available_chunks.end(); ++it){
-    if (*it < 0 || k+m <= *it) return -EINVAL;
-  }
-
-  for (set<int>::iterator it = want_to_read.begin(); it != want_to_read.end(); ++it){
-    if (*it < 0 || k+m <= *it) return -EINVAL;
-  }
-
-  int want[k + m];
-  int avails[k + m];
-  int minimum[k + m];
-
-  memset(want, 0, sizeof(want));
-  memset(avails, 0, sizeof(avails));
-  memset(minimum, 0, sizeof(minimum));
-  (*minimum_chunks).clear();
-
-  for (set<int>::const_iterator i = want_to_read.begin();
-       i != want_to_read.end();
-       ++i) {
-    want[*i] = 1;
-  }
-
-  for (set<int>::const_iterator i = available_chunks.begin();
-       i != available_chunks.end();
-       ++i) {
-    avails[*i] = 1;
-  }
-
-  {
-    int decoding_matrix[k*k];
-    int dm_row[k];
-    int dm_column[k];
-    memset(decoding_matrix, 0, sizeof(decoding_matrix));
-    memset(dm_row, 0, sizeof(dm_row));
-    memset(dm_column, 0, sizeof(dm_column));
-    if (shec_make_decoding_matrix(true, want, avails, decoding_matrix, dm_row, dm_column, minimum) < 0) {
-      return -EIO;
-    }
-  }
-
-  for (int i = 0; i < k + m; i++) {
-    if (minimum[i] == 1) minimum_chunks->insert(i);
-  }
-
-  return 0;
-}
-
-int ErasureCodeShec::minimum_to_decode_with_cost(const set<int> &want_to_read,
-						 const map<int, int> &available,
-						 set<int> *minimum_chunks)
-{
-  set <int> available_chunks;
-
-  for (map<int, int>::const_iterator i = available.begin();
-       i != available.end();
-       ++i)
-    available_chunks.insert(i->first);
-
-  return minimum_to_decode(want_to_read, available_chunks, minimum_chunks);
-}
-
-int ErasureCodeShec::encode(const set<int> &want_to_encode,
-			    const bufferlist &in,
-			    map<int, bufferlist> *encoded)
-{
-  unsigned int k = get_data_chunk_count();
-  unsigned int m = get_chunk_count() - k;
-  bufferlist out;
-
-  if (!encoded || !encoded->empty()){
-    return -EINVAL;
-  }
-
-  int err = encode_prepare(in, *encoded);
-  if (err)
-    return err;
-  encode_chunks(want_to_encode, encoded);
-  for (unsigned int i = 0; i < k + m; i++) {
-    if (want_to_encode.count(i) == 0)
-      encoded->erase(i);
-  }
-  return 0;
-}
-
-int ErasureCodeShec::encode_chunks(const set<int> &want_to_encode,
-				   map<int, bufferlist> *encoded)
-{
-  char *chunks[k + m];
-  for (int i = 0; i < k + m; i++){
-    chunks[i] = (*encoded)[i].c_str();
-  }
-  shec_encode(&chunks[0], &chunks[k], (*encoded)[0].length());
-  return 0;
-}
-
-int ErasureCodeShec::decode(const set<int> &want_to_read,
-			    const map<int, bufferlist> &chunks,
-			    map<int, bufferlist> *decoded)
-{
-  vector<int> have;
-
-  if (!decoded || !decoded->empty()){
-    return -EINVAL;
-  }
-
-  have.reserve(chunks.size());
-  for (map<int, bufferlist>::const_iterator i = chunks.begin();
-       i != chunks.end();
-       ++i) {
-    have.push_back(i->first);
-  }
-  if (includes(
-	have.begin(), have.end(), want_to_read.begin(), want_to_read.end())) {
-    for (set<int>::iterator i = want_to_read.begin();
-	 i != want_to_read.end();
-	 ++i) {
-      (*decoded)[*i] = chunks.find(*i)->second;
-    }
-    return 0;
-  }
-  unsigned int k = get_data_chunk_count();
-  unsigned int m = get_chunk_count() - k;
-  unsigned blocksize = (*chunks.begin()).second.length();
-  for (unsigned int i =  0; i < k + m; i++) {
-    if (chunks.find(i) == chunks.end()) {
-      bufferptr ptr(buffer::create_aligned(blocksize, SIMD_ALIGN));
-      (*decoded)[i].push_front(ptr);
-    } else {
-      (*decoded)[i] = chunks.find(i)->second;
-      (*decoded)[i].rebuild_aligned(SIMD_ALIGN);
-    }
-  }
-  return decode_chunks(want_to_read, chunks, decoded);
-}
-
-int ErasureCodeShec::decode_chunks(const set<int> &want_to_read,
-				   const map<int, bufferlist> &chunks,
-				   map<int, bufferlist> *decoded)
-{
-  unsigned blocksize = (*chunks.begin()).second.length();
-  int erased[k + m];
-  int erased_count = 0;
-  int avails[k + m];
-  char *data[k];
-  char *coding[m];
-
-  for (int i = 0; i < k + m; i++) {
-    erased[i] = 0;
-    if (chunks.find(i) == chunks.end()) {
-      if (want_to_read.count(i) > 0) {
-	erased[i] = 1;
-	erased_count++;
-      }
-      avails[i] = 0;
-    } else {
-      avails[i] = 1;
-    }
-    if (i < k)
-      data[i] = (*decoded)[i].c_str();
-    else
-      coding[i - k] = (*decoded)[i].c_str();
-  }
-
-  if (erased_count > 0) {
-    return shec_decode(erased, avails, data, coding, blocksize);
-  } else {
-    return 0;
-  }
-}
-
-//
-// ErasureCodeShecReedSolomonVandermonde
-//
-
-void ErasureCodeShecReedSolomonVandermonde::shec_encode(char **data,
-					     char **coding,
-					     int blocksize)
-{
-  jerasure_matrix_encode(k, m, w, matrix, data, coding, blocksize);
-}
-
-int ErasureCodeShecReedSolomonVandermonde::shec_decode(int *erased,
-					    int *avails,
-					    char **data,
-					    char **coding,
-					    int blocksize)
-{
-  return shec_matrix_decode(erased, avails, data, coding, blocksize);
-}
-
-unsigned ErasureCodeShecReedSolomonVandermonde::get_alignment() const
-{
-  return k*w*sizeof(int);
-}
-
-int ErasureCodeShecReedSolomonVandermonde::parse(const ErasureCodeProfile &profile)
-{
-  int err = 0;
-  // k, m, c
-  if (profile.find("k") == profile.end() &&
-      profile.find("m") == profile.end() &&
-      profile.find("c") == profile.end()){
-    dout(10) << "(k, m, c) default to " << "(" << DEFAULT_K
-	     << ", " << DEFAULT_M << ", " << DEFAULT_C << ")" << dendl;
-    k = DEFAULT_K; m = DEFAULT_M; c = DEFAULT_C;
-  } else if (profile.find("k") == profile.end() ||
-	     profile.find("m") == profile.end() ||
-	     profile.find("c") == profile.end()){
-    dout(10) << "(k, m, c) must be chosen" << dendl;
-    err = -EINVAL;
-  } else {
-    std::string err_k, err_m, err_c, value_k, value_m, value_c;
-    value_k = profile.find("k")->second;
-    value_m = profile.find("m")->second;
-    value_c = profile.find("c")->second;
-    k = strict_strtol(value_k.c_str(), 10, &err_k);
-    m = strict_strtol(value_m.c_str(), 10, &err_m);
-    c = strict_strtol(value_c.c_str(), 10, &err_c);
-
-    if (!err_k.empty() || !err_m.empty() || !err_c.empty()){
-      if (!err_k.empty()){
-	derr << "could not convert k=" << value_k << "to int" << dendl;
-      } else if (!err_m.empty()){
-	derr << "could not convert m=" << value_m << "to int" << dendl;
-      } else if (!err_c.empty()){
-	derr << "could not convert c=" << value_c << "to int" << dendl;
-      }
-      err = -EINVAL;
-    } else if (k <= 0){
-      derr << "k=" << k
-	   << " must be a positive number" << dendl;
-      err = -EINVAL;
-    } else if (m <= 0){
-      derr << "m=" << m
-	   << " must be a positive number" << dendl;
-      err = -EINVAL;
-    } else if (c <= 0){
-      derr << "c=" << c
-	   << " must be a positive number" << dendl;
-      err = -EINVAL;
-    } else if (m < c){
-      derr << "c=" << c
-	   << " must be less than or equal to m=" << m << dendl;
-      err = -EINVAL;
-    } else if (k > 12){
-      derr << "k=" << k
-	   << " must be less than or equal to 12" << dendl;
-      err = -EINVAL;
-    } else if (k+m > 20){
-      derr << "k+m=" << k+m
-	   << " must be less than or equal to 20" << dendl;
-      err = -EINVAL;
-    } else if (k<m){
-      derr << "m=" << m
-	   << " must be less than or equal to k=" << k << dendl;
-      err = -EINVAL;
-    }
-  }
-
-  if (err) {
-    derr << "(k, m, c)=(" << k << ", " << m << ", " << c
-	 << ") is not a valid parameter." << dendl;
-    return err;
-  }
-
-  dout(10) << "(k, m, c) set to " << "(" << k << ", " << m << ", "
-	   << c << ")"<< dendl;
-
-  // w
-  if (profile.find("w") == profile.end()){
-    dout(10) << "w default to " << DEFAULT_W << dendl;
-    w = DEFAULT_W;
-  } else {
-    std::string err_w, value_w;
-    value_w = profile.find("w")->second;
-    w = strict_strtol(value_w.c_str(), 10, &err_w);
-
-    if (!err_w.empty()){
-      derr << "could not convert w=" << value_w << "to int" << dendl;
-      dout(10) << "w default to " << DEFAULT_W << dendl;
-      w = DEFAULT_W;
-
-    } else if (w != 8 && w != 16 && w != 32) {
-      derr << "w=" << w
-	   << " must be one of {8, 16, 32}" << dendl;
-      dout(10) << "w default to " << DEFAULT_W << dendl;
-      w = DEFAULT_W;
-
-    } else {
-      dout(10) << "w set to " << w << dendl;
-    }
-  }
-  return 0;
-}
-
-void ErasureCodeShecReedSolomonVandermonde::prepare()
-{
-  // setup shared encoding table
-  int** p_enc_table =
-    tcache.getEncodingTable(technique, k, m, c, w);
-
-  if (!*p_enc_table) {
-    dout(10) << "[ cache tables ] creating coeff for k=" <<
-      k << " m=" << m << " c=" << c << " w=" << w << dendl;
-
-    matrix = shec_reedsolomon_coding_matrix(technique);
-
-    // either our new created table is stored or if it has been
-    // created in the meanwhile the locally allocated table will be
-    // freed by setEncodingTable
-    matrix = tcache.setEncodingTable(technique, k, m, c, w, matrix);
-
-    dout(10) << "matrix = " << dendl;
-    for (int i=0; i<m; i++) {
-      char mat[k+1];
-      for (int j=0; j<k; j++) {
-        if (matrix[i*k+j] > 0) {
-          mat[j] = '1';
-        } else {
-          mat[j] = '0';
-        }
-      }
-      mat[k] = '\0';
-      dout(10) << mat << dendl;
-    }
-  } else {
-    matrix = *p_enc_table;
-  }
-
-  dout(10) << " [ technique ] = " <<
-    ((technique == MULTIPLE) ? "multiple" : "single") << dendl;
-
-  assert((technique == SINGLE) || (technique == MULTIPLE));
-
-}
-
-// ErasureCodeShec::
-// Mearged from shec.cc.
-
-double ErasureCodeShec::shec_calc_recovery_efficiency1(int k, int m1, int m2, int c1, int c2){
-  int r_eff_k[k];
-  double r_e1;
-  int i, rr, cc, start, end;
-  int first_flag;
-
-  if (m1 < c1 || m2 < c2) return -1;
-  if ((m1 == 0 && c1 != 0) || (m2 == 0 && c2 != 0)) return -1;
-
-  for (i=0; i<k; i++) r_eff_k[i] = 100000000;
-  r_e1 = 0;
-
-  for (rr=0; rr<m1; rr++){
-    start = ((rr*k)/m1) % k;
-    end = (((rr+c1)*k)/m1) % k;
-    for (cc=start, first_flag=1; first_flag || cc!=end; cc=(cc+1)%k){
-      first_flag = 0;
-      r_eff_k[cc] = std::min(r_eff_k[cc], ((rr+c1)*k)/m1 - (rr*k)/m1);
-    }
-    r_e1 += ((rr+c1)*k)/m1 - (rr*k)/m1;
-  }
-
-  for (rr=0; rr<m2; rr++){
-    start = ((rr*k)/m2) % k;
-    end = (((rr+c2)*k)/m2) % k;
-    for (cc=start, first_flag=1; first_flag || cc!=end; cc=(cc+1)%k){
-      first_flag = 0;
-      r_eff_k[cc] = std::min(r_eff_k[cc], ((rr+c2)*k)/m2 - (rr*k)/m2);
-    }
-    r_e1 += ((rr+c2)*k)/m2 - (rr*k)/m2;
-  }
-
-  for (i=0; i<k; i++){
-    r_e1 += r_eff_k[i];
-  }
-
-  r_e1 /= (k+m1+m2);
-
-  return r_e1;
-}
-
-int* ErasureCodeShec::shec_reedsolomon_coding_matrix(int is_single)
-{
-  int *matrix;
-  int rr, cc, start, end;
-  int m1, m2, c1, c2;
-
-  if (w != 8 && w != 16 && w != 32) return NULL;
-
-  if (!is_single){
-    int c1_best = -1, m1_best = -1;
-    double min_r_e1 = 100.0;
-
-    // create all multiple shec pattern and choose best.
-
-    for (c1=0; c1 <= c/2; c1++){
-      for (m1=0; m1 <= m; m1++){
-        c2 = c-c1;
-        m2 = m-m1;
-
-        if (m1 < c1 || m2 < c2) continue;
-        if ((m1 == 0 && c1 != 0) || (m2 == 0 && c2 != 0)) continue;
-        if ((m1 != 0 && c1 == 0) || (m2 != 0 && c2 == 0)) continue;
-
-        // minimize r_e1
-
-        if (true) {
-          double r_e1;
-          r_e1 = shec_calc_recovery_efficiency1(k, m1, m2, c1, c2);
-          if (min_r_e1 - r_e1 > std::numeric_limits<double>::epsilon() &&
-	      r_e1 < min_r_e1) {
-            min_r_e1 = r_e1;
-            c1_best = c1;
-            m1_best = m1;
-          }
-        }
-      }
-    }
-    m1 = m1_best;
-    c1 = c1_best;
-    m2 = m - m1_best;
-    c2 = c - c1_best;
-  } else {
-    m1 = 0;
-    c1 = 0;
-    m2 = m;
-    c2 = c;
-  }
-
-  // create matrix
-  matrix = reed_sol_vandermonde_coding_matrix(k, m, w);
-
-  for (rr=0; rr<m1; rr++){
-    end = ((rr*k)/m1) % k;
-    start = (((rr+c1)*k)/m1) % k;
-    for (cc=start; cc!=end; cc=(cc+1)%k){
-      matrix[cc + rr*k] = 0;
-    }
-  }
-
-  for (rr=0; rr<m2; rr++){
-    end = ((rr*k)/m2) % k;
-    start = (((rr+c2)*k)/m2) % k;
-    for (cc=start; cc!=end; cc=(cc+1)%k){
-      matrix[cc + (rr+m1)*k] = 0;
-    }
-  }
-
-  return matrix;
-}
-
-int ErasureCodeShec::shec_make_decoding_matrix(bool prepare, int *want_, int *avails,
-                                               int *decoding_matrix, int *dm_row, int *dm_column,
-                                               int *minimum)
-{
-  int mindup = k+1, minp = k+1;
-  int want[k + m];
-
-  memset(want, 0, sizeof(want));
-
-  for (int i = 0; i < k + m; ++i) {
-    want[i] = want_[i];
-  }
-
-  for (int i = 0; i < m; ++i) {
-    if (want[i + k] && !avails[i + k]) {
-      for (int j=0; j < k; ++j) {
-        if (matrix[i * k + j] > 0) {
-          want[j] = 1;
-        }
-      }
-    }
-  }
-
-  if (tcache.getDecodingTableFromCache(decoding_matrix,
-                                       dm_row, dm_column, minimum,
-                                       technique,
-                                       k, m, c, w,
-                                       want, avails)) {
-    return 0;
-  }
-
-  for (unsigned long long pp = 0; pp < (1ull << m); ++pp) {
-
-    // select parity chunks
-    int ek = 0;
-    int p[m];
-    for (int i=0; i < m; ++i) {
-      if (pp & (1ull << i)) {
-        p[ek++] = i;
-      }
-    }
-    if (ek > minp) {
-      continue;
-    }
-
-    // Are selected parity chunks avail?
-    bool ok = true;
-    for (int i = 0; i < ek && ok; i++) {
-      if (!avails[k+p[i]]) {
-        ok = false;
-        break;
-      }
-    }
-
-    if (!ok) {
-      continue;
-    }
-
-    int tmprow[k + m];
-    int tmpcolumn[k];
-    for (int i = 0; i < k + m; i++) {
-      tmprow[i] = 0;
-    }
-    for (int i = 0; i < k; i++) {
-      tmpcolumn[i] = 0;
-    }
-
-    for (int i=0; i < k; i++) {
-      if (want[i] && !avails[i]) {
-        tmpcolumn[i] = 1;
-      }
-    }
-
-    // Parity chunks which are used to recovery erased data chunks, are added to tmprow.
-    for (int i = 0; i < ek; i++) {
-      tmprow[k + p[i]] = 1;
-      for (int j = 0; j < k; j++) {
-        int element = matrix[(p[i]) * k + j];
-        if (element != 0) {
-          tmpcolumn[j] = 1;
-        }
-        if (element != 0 && avails[j] == 1) {
-          tmprow[j] = 1;
-        }
-      }
-    }
-
-    int dup_row = 0, dup_column = 0, dup = 0;
-    for (int i = 0; i < k + m; i++) {
-      if (tmprow[i]) {
-        dup_row++;
-      }
-    }
-
-    for (int i = 0; i < k; i++) {
-      if (tmpcolumn[i]) {
-        dup_column++;
-      }
-    }
-
-    if (dup_row != dup_column) {
-      continue;
-    }
-    dup = dup_row;
-    if (dup == 0) {
-      mindup = dup;
-      for (int i = 0; i < k; i++) {
-        dm_row[i] = -1;
-      }
-      for (int i = 0; i < k; i++) {
-        dm_column[i] = -1;
-      }
-      break;
-    }
-
-    // minimum is updated.
-    if (dup < mindup) {
-      int tmpmat[dup * dup];
-      {
-        for (int i = 0, row = 0; i < k + m; i++) {
-          if (tmprow[i]) {
-            for (int j = 0, column = 0; j < k; j++) {
-              if (tmpcolumn[j]) {
-                if (i < k) {
-                  tmpmat[row * dup + column] = (i == j ? 1 : 0);
-                } else {
-                  tmpmat[row * dup + column] = matrix[(i - k) * k + j];
-                }
-                column++;
-              }
-            }
-            row++;
-          }
-        }
-      }
-      int det = calc_determinant(tmpmat, dup);
-
-      if (det != 0) {
-        int row_id = 0;
-        int column_id = 0;
-        for (int i = 0; i < k; i++) {
-          dm_row[i] = -1;
-        }
-        for (int i = 0; i < k; i++) {
-          dm_column[i] = -1;
-        }
-
-        mindup = dup;
-        for (int i=0; i < k + m; i++) {
-          if (tmprow[i]) {
-            dm_row[row_id++] = i;
-          }
-        }
-        for (int i=0; i < k; i++) {
-          if (tmpcolumn[i]) {
-            dm_column[column_id++] = i;
-          }
-        }
-        minp = ek;
-      }
-    }
-  }
-
-
-  if (mindup == k+1) {
-    fprintf(stderr, "shec_make_decoding_matrix(): can't find recover matrix.\n");
-    return -1;
-  }
-
-  for (int i = 0; i < k + m; i++) {
-    minimum[i] = 0;
-  }
-
-  for (int i=0; i < k && dm_row[i] != -1; i++) {
-    minimum[dm_row[i]] = 1;
-  }
-
-  for (int i = 0; i < k; ++i) {
-    if (want[i] && avails[i]) {
-      minimum[i] = 1;
-    }
-  }
-
-  for (int i = 0; i < m; ++i) {
-    if (want[k + i] && avails[k + i] && !minimum[k + i]) {
-      for (int j = 0; j < k; ++j) {
-        if (matrix[i * k + j] > 0 && !want[j]) {
-          minimum[k + i] = 1;
-          break;
-        }
-      }
-    }
-  }
-
-  if (mindup == 0) {
-    return 0;
-  }
-
-  int tmpmat[mindup * mindup];
-  for (int i=0; i < mindup; i++) {
-    for (int j=0; j < mindup; j++) {
-      if (dm_row[i] < k) {
-        tmpmat[i * mindup + j] = (dm_row[i] == dm_column[j] ? 1 : 0);
-      } else {
-        tmpmat[i * mindup + j] = matrix[(dm_row[i] - k) * k + dm_column[j]];
-      }
-    }
-    if (dm_row[i] < k) {
-      for (int j = 0; j < mindup; j++) {
-        if (dm_row[i] == dm_column[j]) {
-          dm_row[i] = j;
-        }
-      }
-    } else {
-      dm_row[i] -= (k - mindup);
-    }
-  }
-
-  if (prepare) {
-    return 0;
-  }
-
-  int ret = jerasure_invert_matrix(tmpmat, decoding_matrix, mindup, w);
-
-  tcache.putDecodingTableToCache(decoding_matrix, dm_row, dm_column, minimum, technique,
-                                 k, m, c, w, want, avails);
-
-  return ret;
-}
-
-int ErasureCodeShec::shec_matrix_decode(int *want, int *avails, char **data_ptrs,
-                                        char **coding_ptrs, int size)
-{
-  int decoding_matrix[k*k];
-  int dm_row[k], dm_column[k];
-  int minimum[k + m];
-
-  memset(decoding_matrix, 0, sizeof(decoding_matrix));
-  memset(dm_row, -1, sizeof(dm_row));
-  memset(dm_column, -1, sizeof(dm_column));
-  memset(minimum, -1, sizeof(minimum));
-
-  if (w != 8 && w != 16 && w != 32) return -1;
-
-  if (shec_make_decoding_matrix(false, want, avails, decoding_matrix,
-                                dm_row, dm_column, minimum) < 0) {
-    return -1;
-  }
-
-  // Get decoding matrix size
-  int dm_size = 0;
-  for (int i = 0; i < k; i++) {
-    if (dm_row[i] == -1) {
-      break;
-    }
-    dm_size++;
-  }
-
-  char *dm_data_ptrs[dm_size];
-  for (int i = 0; i < dm_size; i++) {
-    dm_data_ptrs[i] = data_ptrs[dm_column[i]];
-  }
-
-  // Decode the data drives
-  for (int i = 0; i < dm_size; i++) {
-    if (!avails[dm_column[i]]) {
-      jerasure_matrix_dotprod(dm_size, w, decoding_matrix + (i * dm_size),
-                              dm_row, i, dm_data_ptrs, coding_ptrs, size);
-    }
-  }
-
-  // Re-encode any erased coding devices
-  for (int i = 0; i < m; i++) {
-    if (want[k+i] && !avails[k+i]) {
-      jerasure_matrix_dotprod(k, w, matrix + (i * k), NULL, i+k,
-                              data_ptrs, coding_ptrs, size);
-    }
-  }
-
-  return 0;
-}