Implemented H5DOappend

h5py/api_functions.txt

@@ -121,6 +121,9 @@ hdf5:
   1.10.5    herr_t H5Dget_chunk_info(hid_t dset_id, hid_t fspace_id, hsize_t chk_idx, hsize_t *offset, unsigned *filter_mask, haddr_t *addr, hsize_t *size)
   1.10.5    herr_t H5Dget_chunk_info_by_coord(hid_t dset_id, const hsize_t *offset, unsigned *filter_mask, haddr_t *addr, hsize_t *size)
 
+  # HDF5 Append
+  1.10.0    herr_t H5DOappend(hid_t dset_id, hid_t dxpl_id, unsigned index, size_t num_elem, hid_t memtype, const void *buffer)
+
 
   # === H5E - Minimal error-handling interface ================================
 

h5py/h5d.pyx

@@ -231,6 +231,43 @@ cdef class DatasetID(ObjectID):
 
         dset_rw(self_id, mtype_id, mspace_id, fspace_id, plist_id, data, 0)
 
+    IF HDF5_VERSION >= (1, 10, 2):
+        @with_phil
+        def append(self, ndarray arr_obj not None, uint32_t index, size_t num_elem,
+                TypeID mtype=None, PropID dxpl=None):
+            """ (SpaceID mspace, SpaceID fspace, NDARRAY arr_obj,
+                TypeID mtype=None, PropDXID dxpl=None)
+
+                Write data from a Numpy array to an HDF5 dataset. Keyword dxpl may
+                be a dataset transfer property list.
+
+                It is your responsibility to ensure that the memory dataspace
+                provided is compatible with the shape of the Numpy array.  Since a
+                wide variety of dataspace configurations are possible, this is not
+                checked.  You can easily crash Python by writing data from too
+                large a dataspace.
+
+                If a memory datatype is not specified, one will be auto-created
+                based on the array's dtype.
+
+                The provided Numpy array must be C-contiguous.  If this is not the
+                case, ValueError will be raised and the read will fail.
+            """
+            cdef hid_t self_id, mtype_id, plist_id
+            cdef void* data
+            cdef int oldflags
+
+            if mtype is None:
+                mtype = py_create(arr_obj.dtype)
+            check_numpy_read(arr_obj, -1)
+
+            self_id = self.id
+            mtype_id = mtype.id
+            plist_id = pdefault(dxpl)
+            data = PyArray_DATA(arr_obj)
+
+            H5DOappend(self_id, plist_id, index, num_elem, mtype_id, data)
+
 
     @with_phil
     def extend(self, tuple shape):

h5py/tests/test_dataset.py

@@ -1020,6 +1020,35 @@ def test_len_big(self):
         self.assertEqual(dset.len(), 2 ** 33)
 
 
+class TestAppend(BaseDataset):
+    """
+        Feature: H5DOappend testing
+    """
+    @ut.skipIf(
+        h5py.version.hdf5_version_tuple < (1, 10, 0),
+        "Reading non-existent label segfaults"
+        )
+    def test_append_1(self):
+        dset = self.f.create_dataset('foo', (0, 10), maxshape=(None, 10))
+        for i in range(10):
+            data = np.full(10, i)
+            dset.id.append(data, 0, 1)
+            np.testing.assert_array_equal(dset[-1], data)
+        self.assertEqual(len(dset), 10)
+
+    @ut.skipIf(
+        h5py.version.hdf5_version_tuple < (1, 10, 0),
+        "Reading non-existent label segfaults"
+        )
+    def test_append_2(self):
+        dset = self.f.create_dataset('foo', (0, 10), maxshape=(None, 10))
+        for i in range(5):
+            data = np.full((2, 10), i)
+            dset.id.append(data, 0, 2)
+            np.testing.assert_array_equal(dset[-2:], data)
+        self.assertEqual(len(dset), 10)
+
+
 class TestIter(BaseDataset):
 
     """

news/implement-1890.rst

@@ -0,0 +1,5 @@
+Exposing HDF5 functions
+-----------------------
+
+* Added H5DOappend to exposed C functions
+* Added append to h5d.pyx