From: Loic Dachary <loic@dachary.org>
Date: Tue, 3 Jun 2014 20:20:29 +0000 (+0200)
Subject: erasure-code: parse function for the mapping parameter
X-Git-Tag: v0.85~38^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=164cfe8591108b9d9b7491a83c444da0acf3b890;p=ceph.git

erasure-code: parse function for the mapping parameter

Each D letter is a data chunk. For instance:

    _DDD_DDD

is going to parse into:

   [ 1, 2, 3, 5, 6, 7 ]

the 0 and 4 positions are not used by chunks and do not show in the
mapping. Implement ErasureCode::parse to support a reasonable default
for the mapping parameter.

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

diff --git a/src/erasure-code/ErasureCode.cc b/src/erasure-code/ErasureCode.cc
index 0d3f62f6354d..44da1b32746b 100644
--- a/src/erasure-code/ErasureCode.cc
+++ b/src/erasure-code/ErasureCode.cc
@@ -144,15 +144,36 @@ int ErasureCode::decode_chunks(const set<int> &want_to_read,
 }
 
 int ErasureCode::parse(const map<std::string,std::string> &parameters,
- ostream *ss)
+		       ostream *ss)
 {
-  return 0;
+  return to_mapping(parameters, ss);
 }
 
 const vector<int> &ErasureCode::get_chunk_mapping() const {
   return chunk_mapping;
 }
 
+int ErasureCode::to_mapping(const map<std::string,std::string> &parameters,
+			    ostream *ss)
+{
+  if (parameters.find("mapping") != parameters.end()) {
+    std::string mapping = parameters.find("mapping")->second;
+    int position = 0;
+    vector<int> coding_chunk_mapping;
+    for(std::string::iterator it = mapping.begin(); it != mapping.end(); ++it) {
+      if (*it == 'D')
+	chunk_mapping.push_back(position);
+      else
+	coding_chunk_mapping.push_back(position);
+      position++;
+    }
+    chunk_mapping.insert(chunk_mapping.end(),
+			 coding_chunk_mapping.begin(),
+			 coding_chunk_mapping.end());
+  }
+  return 0;
+}
+
 int ErasureCode::to_int(const std::string &name,
 			const map<std::string,std::string> &parameters,
 			int *value,
diff --git a/src/erasure-code/ErasureCode.h b/src/erasure-code/ErasureCode.h
index 637a009d78c2..dec2bd9b1a8e 100644
--- a/src/erasure-code/ErasureCode.h
+++ b/src/erasure-code/ErasureCode.h
@@ -64,6 +64,9 @@ namespace ceph {
 
     virtual const vector<int> &get_chunk_mapping() const;
 
+    int to_mapping(const map<std::string,std::string> &parameters,
+		   ostream *ss);
+
     static int to_int(const std::string &name,
 		      const map<std::string,std::string> &parameters,
 		      int *value,