ErasureCodeJerasure: define technique ReedSolomonVandermonde

technique == reed_sol_van

parse : default to K=7, M=3 and W=8 . If W is not 8, 16 or 32, it
reverts to 8.

pad_in_length : pad to a multiple of k*w*sizeof(int)

prepare, jerasure_encode, jerasure_decode map directly to the matching
jerasure functions

https://github.com/dachary/ceph/tree/wip-5879 refs #5879

Signed-off-by: Loic Dachary <loic@dachary.org>

3 files changed, 64 insertions, 0 deletions

diff --git a/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.cc b/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.cc
index 5a5c4ce4e59..9cdbca67d5d 100644
--- a/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.cc
+++ b/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.cc
@@ -161,3 +161,39 @@ bool ErasureCodeJerasure::is_prime(int value) {
   return false;
 }
 
+// 
+// ErasureCodeJerasureReedSolomonVandermonde
+//
+void ErasureCodeJerasureReedSolomonVandermonde::jerasure_encode(char **data,
+                                                                char **coding,
+                                                                int blocksize) {
+  jerasure_matrix_encode(k, m, w, matrix, data, coding, blocksize);
+}
+
+int ErasureCodeJerasureReedSolomonVandermonde::jerasure_decode(int *erasures,
+                                                                char **data,
+                                                                char **coding,
+                                                                int blocksize) {
+  return jerasure_matrix_decode(k, m, w, matrix, 1, erasures, data, coding, blocksize);
+}
+
+unsigned ErasureCodeJerasureReedSolomonVandermonde::pad_in_length(unsigned in_length) {
+  while (in_length%(k*w*sizeof(int)) != 0) 
+    in_length++;
+  return in_length;
+}
+
+void ErasureCodeJerasureReedSolomonVandermonde::parse(const map<std::string,std::string> &parameters) {
+  k = to_int("erasure-code-k", parameters, DEFAULT_K);
+  m = to_int("erasure-code-m", parameters, DEFAULT_M);
+  w = to_int("erasure-code-w", parameters, DEFAULT_W);
+  if (w != 8 && w != 16 && w != 32) {
+    derr << "ReedSolomonVandermonde: w=" << w << " must be one of {8, 16, 32} : revert to 8 " << dendl;
+    w = 8;
+  }
+}
+
+void ErasureCodeJerasureReedSolomonVandermonde::prepare() {
+  matrix = reed_sol_vandermonde_coding_matrix(k, m, w);
+}
+
diff --git a/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.h b/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.h
index 2a8ed268f8a..5b058f8b54c 100644
--- a/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.h
+++ b/src/osd/ErasureCodePluginJerasure/ErasureCodeJerasure.h
@@ -65,4 +65,31 @@ public:
   static bool is_prime(int value);
 };
 
+class ErasureCodeJerasureReedSolomonVandermonde : public ErasureCodeJerasure {
+public:
+  static const int DEFAULT_K = 7;
+  static const int DEFAULT_M = 3;
+  static const int DEFAULT_W = 8;
+  int *matrix;
+
+  ErasureCodeJerasureReedSolomonVandermonde() :
+    ErasureCodeJerasure("reed_sol_van"),
+    matrix(0)
+  { }
+  virtual ~ErasureCodeJerasureReedSolomonVandermonde() {
+    if (matrix)
+      free(matrix);
+  }
+
+  virtual void jerasure_encode(char **data,
+                               char **coding,
+                               int blocksize);
+  virtual int jerasure_decode(int *erasures,
+                               char **data,
+                               char **coding,
+                               int blocksize);
+  virtual unsigned pad_in_length(unsigned in_length);
+  virtual void parse(const map<std::string,std::string> &parameters);
+  virtual void prepare();
+};
 #endif
diff --git a/src/test/osd/TestErasureCodeJerasure.cc b/src/test/osd/TestErasureCodeJerasure.cc
index 96fc834b10e..343d3df36d3 100644
--- a/src/test/osd/TestErasureCodeJerasure.cc
+++ b/src/test/osd/TestErasureCodeJerasure.cc
@@ -26,6 +26,7 @@ class ErasureCodeTest : public ::testing::Test {
 };
 
 typedef ::testing::Types<
+  ErasureCodeJerasureReedSolomonVandermonde,
 > JerasureTypes;
 TYPED_TEST_CASE(ErasureCodeTest, JerasureTypes);