From c38d49913241964be97ab8941bb50cf8c8c80f41 Mon Sep 17 00:00:00 2001
From: Eugen Wintersberger <eugen.wintersberger@gmail.com>
Date: Sat, 12 Jan 2019 21:09:48 +0100
Subject: [PATCH] Added data transform to the data transfer property list

Update #318
---
 src/h5cpp/property/dataset_transfer.cpp | 67 +++++++++++++++++++++++++
 src/h5cpp/property/dataset_transfer.hpp | 34 +++++++++++++
 test/property/dataset_transfer_test.cpp |  8 +++
 3 files changed, 109 insertions(+)

diff --git a/src/h5cpp/property/dataset_transfer.cpp b/src/h5cpp/property/dataset_transfer.cpp
index 1a9e6bc880..440b897575 100644
--- a/src/h5cpp/property/dataset_transfer.cpp
+++ b/src/h5cpp/property/dataset_transfer.cpp
@@ -29,6 +29,9 @@
 #include <h5cpp/property/property_class.hpp>
 #include <h5cpp/error/error.hpp>
 #include <sstream>
+#include <algorithm>
+#include <vector>
+#include <iterator>
 
 namespace hdf5 {
 namespace property {
@@ -47,6 +50,70 @@ DatasetTransferList::DatasetTransferList(ObjectHandle &&handle) :
   }
 }
 
+void DatasetTransferList::data_transform(const std::string &transform) const
+{
+  data_transform(transform.data());
+}
+
+void DatasetTransferList::data_transform(const char *transform) const
+{
+  herr_t status = H5Pset_data_transform(static_cast<hid_t>(*this),transform);
+  if(status<0)
+  {
+    error::Singleton::instance().throw_with_stack("Failure to set data transform expression!");
+  }
+}
+
+ssize_t DatasetTransferList::data_transform_size() const
+{
+  ssize_t size = H5Pget_data_transform(static_cast<hid_t>(*this),NULL,0);
+  if(size<0)
+  {
+    error::Singleton::instance().throw_with_stack("Failure to get the size of the data transform expression!");
+  }
+
+  return size;
+}
+
+bool DatasetTransferList::has_data_transform() const
+{
+  ssize_t size = data_transform_size();
+  if(size == 0)
+  {
+    return false;
+  }
+  else if(size > 0)
+  {
+    return true;
+  }
+
+  return false;
+}
+
+std::string DatasetTransferList::data_transform() const
+{
+  if(has_data_transform())
+  {
+    std::vector<char> buffer(data_transform_size()+1);
+    herr_t status = H5Pget_data_transform(static_cast<hid_t>(*this),
+                                          buffer.data(),buffer.size()+1);
+    if(status<0)
+    {
+      error::Singleton::instance().throw_with_stack("Failure to retrieve the data transformation expression!");
+    }
+
+    std::string expression(buffer.data(),buffer.size()-1);
+
+    return expression;
+  }
+  else
+  {
+    return std::string();
+  }
+}
+
+
+
 #ifdef WITH_MPI
 
 #ifdef __GNUC__
diff --git a/src/h5cpp/property/dataset_transfer.hpp b/src/h5cpp/property/dataset_transfer.hpp
index 5ea3b2faf5..bebf8963cd 100644
--- a/src/h5cpp/property/dataset_transfer.hpp
+++ b/src/h5cpp/property/dataset_transfer.hpp
@@ -51,12 +51,46 @@ std::ostream &operator<<(std::ostream &stream,const MPIChunkOption &option);
 #endif
 
 class DLL_EXPORT DatasetTransferList : public List {
+  private:
+    ssize_t data_transform_size() const;
  public:
+
   DatasetTransferList();
   ~DatasetTransferList();
 
   explicit DatasetTransferList(ObjectHandle &&handle);
 
+  //!
+  //! \brief set a data transform
+  //!
+  //! \param transform string with the transformation expression
+  //!
+  void data_transform(const std::string &transform) const;
+
+  //!
+  //! \brief set a data transform
+  //!
+  //! \param transform pointer to the transform string
+  //! \param size length of the transformation string
+  //!
+  void data_transform(const char *transform) const;
+
+  //!
+  //! \brief check if a data transform is set
+  //!
+  bool has_data_transform() const;
+
+  //!
+  //! \brief get transform expression
+  //!
+  //! Returns a string with the expression representing the data transform.
+  //! If no data transform is set on the transfer property list an empty
+  //! string is returned.
+  //!
+  //! \return string with the transformation expression
+  //!
+  std::string data_transform() const;
+
 #ifdef WITH_MPI
   void mpi_transfer_mode(MPITransferMode mode) const;
   MPITransferMode mpi_transfer_mode() const;
diff --git a/test/property/dataset_transfer_test.cpp b/test/property/dataset_transfer_test.cpp
index 00d0f79e05..9f19f39982 100644
--- a/test/property/dataset_transfer_test.cpp
+++ b/test/property/dataset_transfer_test.cpp
@@ -55,6 +55,14 @@ TEST(DatasetTransferList,test_as_default_argument)
   EXPECT_NO_THROW(test_function());
 }
 
+TEST(DatasetTransferList,test_data_transform)
+{
+  pl::DatasetTransferList dxpl;
+  std::string transform_expression="x+1";
+  EXPECT_NO_THROW(dxpl.data_transform(transform_expression));
+  EXPECT_EQ("x+1",dxpl.data_transform());
+}
+
 #ifdef WITH_MPI
 
 TEST(DatasetTransferList, flags)