Add H5Treclaim API and implement quick example usage for object reads

h5py/api_functions.txt

@@ -513,6 +513,7 @@ hdf5:
   hid_t         H5Tget_native_type(hid_t type_id, H5T_direction_t direction)
   herr_t        H5Tcommit(hid_t loc_id, char *name, hid_t dtype_id, hid_t lcpl_id, hid_t tcpl_id, hid_t tapl_id)
   hid_t         H5Tget_create_plist(hid_t dtype_id)
+  1.12.0 herr_t H5Treclaim(hid_t type_id, hid_t space_id, hid_t plist_id, void *buf)
 
   hid_t         H5Tdecode(unsigned char *buf)
   herr_t        H5Tencode(hid_t obj_id, unsigned char *buf, size_t *nalloc)

h5py/h5a.pyx

@@ -12,6 +12,8 @@
     Provides access to the low-level HDF5 "H5A" attribute interface.
 """
 
+include "config.pxi"
+
 # C-level imports
 from ._objects cimport pdefault
 from .h5t cimport TypeID, typewrap, py_create
@@ -441,3 +443,30 @@ cdef class AttrID(ObjectID):
         Get the amount of storage required for this attribute.
         """
         return H5Aget_storage_size(self.id)
+
+    IF HDF5_VERSION >= (1, 12, 0):
+
+        @with_phil
+        def reclaim(self, ndarray arr not None, TypeID mtype=None):
+            """ no return
+
+            Reclaims memory allocated by the HDF5 library after reading
+            from an attribute with a variable-length or reference datatype
+            """
+            cdef mspace_id, mtype_id
+            cdef void* data
+
+            try:
+                if mtype is None:
+                    mtype = py_create(arr.dtype)
+
+                mspace_id = H5Aget_space(self.id)
+
+                mtype_id = mtype.id
+                data = PyArray_DATA(arr)
+
+                H5Treclaim(mtype_id, mspace_id, H5P_DEFAULT, data)
+
+            finally:
+                if mspace_id:
+                    H5Aclose(mspace_id)

h5py/h5d.pyx

@@ -463,6 +463,36 @@ cdef class DatasetID(ObjectID):
         """
         H5Drefresh(self.id)
 
+    IF HDF5_VERSION >= (1, 12, 0):
+
+        @with_phil
+        def reclaim(self, SpaceID mspace not None, ndarray arr_obj not None, TypeID mtype=None):
+            """ no return
+
+            Reclaims memory allocated by the HDF5 library after reading
+            from a dataset with a variable-length or reference datatype
+            """
+            cdef mspace_id, mtype_id
+            cdef void* data
+
+            try:
+                if mtype is None:
+                    mtype = py_create(arr_obj.dtype)
+
+                if mspace.id == H5S_ALL:
+                    mspace_id = H5Dget_space(self.id)
+                else:
+                    mspace_id = mspace.id
+
+                mtype_id = mtype.id
+                data = PyArray_DATA(arr_obj)
+
+                H5Treclaim(mtype_id, mspace_id, H5P_DEFAULT, data)
+
+            finally:
+                if mspace_id:
+                    H5Sclose(mspace_id)
+
     def write_direct_chunk(self, offsets, data, filter_mask=0x00000000, PropID dxpl=None):
         """ (offsets, data, uint32_t filter_mask=0x00000000, PropID dxpl=None)
 
@@ -510,7 +540,6 @@ cdef class DatasetID(ObjectID):
             if space_id:
                 H5Sclose(space_id)
 
-
     @cython.boundscheck(False)
     @cython.wraparound(False)
     def read_direct_chunk(self, offsets, PropID dxpl=None, unsigned char[::1] out=None):