implement string attribute reading in c++ api

also fix related bug in napi5 refs #417
nexusformat · Apr 12, 2016 · c431b5c · c431b5c
1 parent 86f5e09
commit c431b5c
Show file tree

Hide file tree

Showing 3 changed files with 87 additions and 15 deletions.
diff --git a/bindings/cpp/NeXusFile.cpp b/bindings/cpp/NeXusFile.cpp
@@ -1109,14 +1109,38 @@ AttrInfo File::getNextAttr() {
   //string & name, int & length, NXnumtype type) {
   char name[NX_MAXNAMELEN];
   int type;
-  int length;
-  NXstatus status = NXgetnextattr(this->m_file_id, name, &length, &type);
+  int rank;
+  int dim[NX_MAXRANK];
+  NXstatus status = NXgetnextattra(this->m_file_id, name, &rank, dim, &type);
   if (status == NX_OK) {
     AttrInfo info;
     info.type = static_cast<NXnumtype>(type);
-    info.length = length;
     info.name = string(name);
-    return info;
+
+    // scalar value
+    if (rank == 0 || (rank == 1 && dim[0] == 1)) {
+      info.length = 1;
+      return info;
+    }
+
+    // char (=string) or number array (1 dim)
+    if (rank == 1) {
+      info.length = dim[0];
+      return info;
+    }
+
+    // string array (2 dim char array)
+    if (rank == 2 && type == NX_CHAR) {
+      info.length = 1;
+      for( unsigned int d=0; d<rank; ++d){
+        info.dims.push_back(dim[d]);
+        info.length *= dim[d];
+      }
+      return info;
+    }
+
+    std::cerr << "ERROR iterating through attributes found array attribute not understood by this api" << std::endl;
+    throw Exception("getNextAttr failed", NX_ERROR);
   }
   else if (status == NX_EOD) {
     AttrInfo info;
@@ -1214,6 +1238,48 @@ string File::getStrAttr(const AttrInfo & info) {
   return res;
 }
 
+void File::getAttr(const std::string& name, std::vector<std::string>& array) {
+  if (name == NULL_STR) {
+    throw Exception("Supplied bad attribute name \"" + NULL_STR + "\"");
+  }
+  if (name.empty()) {
+    throw Exception("Supplied empty name to getAttr");
+  }
+
+  // get attrInfo
+  char attr_name[name.size()+1];
+  strcpy(attr_name, name.c_str());
+
+  int type;
+  int rank;
+  int dim[NX_MAXRANK];
+  NXstatus status = NXgetattrainfo(this->m_file_id, attr_name, &rank, dim, &type);
+  if (status != NX_OK) {
+    throw Exception("Attribute \"" + name + "\" not found");
+  }
+
+  if (rank != 2 || type != NX_CHAR) {
+    throw Exception("Attribute is not an array of strings");
+  }
+
+  // read data
+  std::string sep(", ");
+  char* char_data = new char[dim[0] * (dim[1] + sep.size())];
+  status = NXgetattra(this->m_file_id, attr_name, char_data);
+
+  // split data to strings
+  std::string data(char_data);
+
+  std::size_t start = 0;
+  std::size_t end = data.find(sep, start);
+  while( end!=std::string::npos) {
+    array.push_back(data.substr(start, (end-start)));
+    start = end+sep.size();
+    end = data.find(sep, start);
+  }
+  array.push_back(data.substr(start));
+}
+
 vector<AttrInfo> File::getAttrInfos() {
   vector<AttrInfo> infos;
   this->initAttrDir();

diff --git a/bindings/cpp/NeXusFile.hpp b/bindings/cpp/NeXusFile.hpp
@@ -100,6 +100,8 @@ namespace NeXus {
     unsigned length;
     /** The name of the attribute. */
     std::string name;
+    /** The dimensions of the attribute. */
+    std::vector<int> dims;
   };
 
   /**
@@ -779,6 +781,15 @@ namespace NeXus {
      */
     std::string getStrAttr(const AttrInfo & info);
 
+    /**
+     * Get the value of a string array attribute.
+     *
+     * \param info Which attribute to read.
+     *
+     * \param array The values of the attribute.
+     */
+    void getAttr(const std::string& name, std::vector<std::string>& array);
+
     /**
      * \return The id of the group used for linking.
      */

diff --git a/src/napi5.c b/src/napi5.c
@@ -123,22 +123,18 @@ static herr_t readStringAttribute(hid_t attr, char **data)
 		}
 	} else if (ndims == 1) {
 		int i;
-		hid_t memtype;
 		char **strings;
 
 		strings = (char **) malloc(thedims[0] * sizeof(char*));
-		memtype = H5Tcopy(H5T_C_S1);
-		if (H5Tis_variable_str(atype)) {
-			H5Tset_size(memtype, H5T_VARIABLE);
-		} else {
-			strings[0] = (char *) malloc(thedims[0] * (sdim + 1) * sizeof(char));
+
+		if (! H5Tis_variable_str(atype)) {
+			strings[0] = (char *) malloc(thedims[0] * sdim * sizeof(char));
 			for(i=1; i<thedims[0]; i++) {
-				strings[i] = strings[0] + i * (sdim + 1);
+				strings[i] = strings[0] + i * sdim;
 			}
-			H5Tset_size(memtype, sdim + 1);
 		}
 
-		iRet = H5Aread(attr, memtype, strings);
+                iRet = H5Aread(attr, atype, strings[0]);
 		*data = malloc((sdim + 2) * thedims[0] * sizeof(char));
 		for(i=0; i<thedims[0]; i++) {
 			if (i==0) {
@@ -149,13 +145,12 @@ static herr_t readStringAttribute(hid_t attr, char **data)
 			}
 		}
 		if (H5Tis_variable_str(atype)) {
-			H5Dvlen_reclaim(memtype, space, H5P_DEFAULT, strings);
+			H5Dvlen_reclaim(atype, space, H5P_DEFAULT, strings);
 		} else {
 			free(strings[0]);
 		}
 
 		free(strings);
-		H5Tclose(memtype);
 	} else {
 		*data = strdup(" higher dimensional string array");
 	}