Added h5ex_d_alloc HDF group example

Update #318

examples/CMakeLists.txt

@@ -52,6 +52,7 @@ add_dependencies(examples
 #
 
 add_subdirectory(attributes)
+add_subdirectory(hdfgroup)
 
 if (H5CPP_SWMR_ENABLED)
   add_subdirectory(swmr)

examples/hdfgroup/CMakeLists.txt

@@ -0,0 +1,9 @@
+
+
+#-----------------------------------------------------------------------------
+# Build the C Examples
+#-----------------------------------------------------------------------------
+add_subdirectory (H5D)
+add_subdirectory (H5G)
+add_subdirectory (H5T)
+#add_subdirectory (${PROJECT_SOURCE_DIR}/Performance ${PROJECT_BINARY_DIR}/Performance)

examples/hdfgroup/H5D/CMakeLists.txt

@@ -0,0 +1,3 @@
+
+add_executable(h5ex_d_alloc h5ex_d_alloc.cpp)
+target_link_libraries(h5ex_d_alloc h5cpp) 

examples/hdfgroup/H5D/h5ex_d_alloc.cpp

@@ -0,0 +1,126 @@
+/************************************************************
+
+  This example shows how to set the space allocation time
+  for a dataset.  The program first creates two datasets,
+  one with the default allocation time (late) and one with
+  early allocation time, and displays whether each has been
+  allocated and their allocation size.  Next, it writes data
+  to the datasets, and again displays whether each has been
+  allocated and their allocation size.
+
+  This file is intended for use with HDF5 Library version 1.8
+
+ ************************************************************/
+
+#include <h5cpp/hdf5.hpp>
+#include <array>
+#include <algorithm>
+
+
+#define FILE            "h5ex_d_alloc.h5"
+#define DATASET1        "DS1"
+#define DATASET2        "DS2"
+#define DIM0            4
+#define DIM1            7
+#define FILLVAL         99
+
+int32_t generate()
+{
+  static int32_t value = 0;
+  return value++;
+}
+
+using namespace hdf5;
+
+int
+main (void)
+{
+    std::array<int32_t,DIM0*DIM1> buffer;
+    std::generate(buffer.begin(),buffer.end(),generate);
+
+    /*
+     * 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 space({DIM0,DIM1});
+
+    /*
+     * Create the dataset creation property list, and set the chunk
+     * size.
+     */
+    property::DatasetCreationList dcpl;
+    property::LinkCreationList lcpl;
+
+    /*
+     * Set the allocation time to "early".  This way we can be sure
+     * that reading from the dataset immediately after creation will
+     * return the fill value.
+     */
+    dcpl.allocation_time(property::DatasetAllocTime::EARLY);
+
+    printf ("Creating datasets...\n");
+    printf ("%s has allocation time H5D_ALLOC_TIME_LATE\n", DATASET1);
+    printf ("%s has allocation time H5D_ALLOC_TIME_EARLY\n\n", DATASET2);
+
+    /*
+     * Create the dataset using the dataset creation property list.
+     */
+    node::Dataset dset1(file.root(),DATASET1,datatype::create<int32_t>(),space);
+    node::Dataset dset2(file.root(),DATASET2,datatype::create<int32_t>(),space,lcpl,dcpl);
+
+    /*
+     * Retrieve and print space status and storage size for dset1.
+     */
+    H5D_space_status_t space_status;
+    H5Dget_space_status (static_cast<hid_t>(dset1), &space_status);
+    hsize_t storage_size = H5Dget_storage_size (static_cast<hid_t>(dset1));
+    printf ("Space for %s has%sbeen allocated.\n", DATASET1,
+                space_status == H5D_SPACE_STATUS_ALLOCATED ? " " : " not ");
+    printf ("Storage size for %s is: %ld bytes.\n", DATASET1,
+                (long) storage_size);
+
+    /*
+     * Retrieve and print space status and storage size for dset2.
+     */
+    H5Dget_space_status (static_cast<hid_t>(dset2), &space_status);
+    storage_size = H5Dget_storage_size (static_cast<hid_t>(dset2));
+    printf ("Space for %s has%sbeen allocated.\n", DATASET2,
+                space_status == H5D_SPACE_STATUS_ALLOCATED ? " " : " not ");
+    printf ("Storage size for %s is: %ld bytes.\n", DATASET2,
+                (long) storage_size);
+
+    printf ("\nWriting data...\n\n");
+
+    /*
+     * Write the data to the datasets.
+     */
+    dset1.write(buffer);
+    dset2.write(buffer);
+
+    /*
+     * Retrieve and print space status and storage size for dset1.
+     */
+    H5Dget_space_status (static_cast<hid_t>(dset1), &space_status);
+    storage_size = H5Dget_storage_size (static_cast<hid_t>(dset1));
+    printf ("Space for %s has%sbeen allocated.\n", DATASET1,
+                space_status == H5D_SPACE_STATUS_ALLOCATED ? " " : " not ");
+    printf ("Storage size for %s is: %ld bytes.\n", DATASET1,
+                (long) storage_size);
+
+    /*
+     * Retrieve and print space status and storage size for dset2.
+     */
+    H5Dget_space_status (static_cast<hid_t>(dset2), &space_status);
+    storage_size = H5Dget_storage_size (static_cast<hid_t>(dset2));
+    printf ("Space for %s has%sbeen allocated.\n", DATASET2,
+                space_status == H5D_SPACE_STATUS_ALLOCATED ? " " : " not ");
+    printf ("Storage size for %s is: %ld bytes.\n", DATASET2,
+                (long) storage_size);
+
+    return 0;
+}