Added chunk example

Update #318

examples/hdfgroup/H5D/CMakeLists.txt

@@ -3,4 +3,7 @@ add_executable(h5ex_d_alloc h5ex_d_alloc.cpp)
 target_link_libraries(h5ex_d_alloc h5cpp) 
 
 add_executable(h5ex_d_checksum h5ex_d_checksum.cpp)
-target_link_libraries(h5ex_d_checksum h5cpp)
+target_link_libraries(h5ex_d_checksum h5cpp)
+
+add_executable(h5ex_d_chunk h5ex_d_chunk.cpp)
+target_link_libraries(h5ex_d_chunk h5cpp)

examples/hdfgroup/H5D/h5ex_d_chunk.cpp

@@ -0,0 +1,105 @@
+/************************************************************
+
+  This example shows how to create a chunked dataset.  The
+  program first writes integers in a hyperslab selection to
+  a chunked dataset with dataspace dimensions of DIM0xDIM1
+  and chunk size of CHUNK0xCHUNK1, then closes the file.
+  Next, it reopens the file, reads back the data, and
+  outputs it to the screen.  Finally it reads the data again
+  using a different hyperslab selection, and outputs
+  the result to the screen.
+
+  This file is intended for use with HDF5 Library version 1.8
+
+ ************************************************************/
+
+#include <h5cpp/hdf5.hpp>
+#include <array>
+#include "matrix_hdf5.hpp"
+
+#define FILE            "h5ex_d_chunk.h5"
+#define DATASET         "DS1"
+#define DIM0            6
+#define DIM1            8
+#define CHUNK0          4
+#define CHUNK1          4
+
+using namespace hdf5;
+
+using Int32Matrix = Matrix<int32_t,DIM0,DIM1>;
+
+void write_data()
+{
+  /*
+   * Create a new file using the default properties.
+   */
+
+  file::File file = file::create (FILE, file::AccessFlags::TRUNCATE);
+
+  /*
+   * Create dataspace.  Setting maximum size to NULL sets the maximum
+   * size to be the current size.
+   */
+  dataspace::Simple file_space({ DIM0, DIM1 });
+
+  /*
+   * Create the dataset creation property list, and set the chunk
+   * size.
+   */
+  property::DatasetCreationList dcpl;
+  dcpl.layout (property::DatasetLayout::CHUNKED);
+  dcpl.chunk (Dimensions{ CHUNK0, CHUNK1 });
+
+  /*
+   * Create the chunked dataset.
+   */
+  property::LinkCreationList lcpl;
+  node::Dataset dset (file.root (), DATASET, datatype::create<int32_t> (),
+                      file_space, lcpl, dcpl);
+
+  /*
+   * Define and select the first part of the hyperslab selection.
+   */
+  file_space.selection(dataspace::SelectionOperation::SET,
+                       dataspace::Hyperslab({ 0, 0 },{ 2, 2 },{ 2, 3 },{ 3, 3 }));
+  file_space.selection(dataspace::SelectionOperation::NOTB,
+                       dataspace::Hyperslab({ 0, 0 },{ 1, 1 },{ 2, 3 },{ 3, 3 }));
+
+
+  /*
+   * Write the data to the dataset.
+   */
+  Int32Matrix matrix(1);
+  std::cout<<"Original data: "<<std::endl<<matrix<<std::endl;
+
+  dset.write (matrix,datatype::create<Int32Matrix>(),file_space,file_space);
+
+}
+
+void read_data()
+{
+  file::File file = file::open(FILE,file::AccessFlags::READONLY);
+  node::Dataset dset = file.root()[DATASET];
+
+  property::DatasetCreationList dcpl = dset.creation_list();
+  std::cout<<"Dataset layout: "<<dcpl.layout()<<std::endl;
+
+  Int32Matrix matrix;
+  dset.read(matrix);
+  std::cout<<std::endl<<matrix<<std::endl;
+
+  matrix = Int32Matrix(0); //reinit array
+  dataspace::Simple file_space = dset.dataspace();
+  file_space.selection(dataspace::SelectionOperation::SET,dataspace::Hyperslab({0,1},{2,3},{2,2},{4,4}));
+  dset.read(matrix,datatype::create<Int32Matrix>(),file_space,file_space);
+  std::cout<<matrix<<std::endl;
+}
+
+int
+main (void)
+{
+    write_data();
+    read_data();
+
+    return 0;
+}