From 1cb46effda75c250c58da506b3b58582e7c8e540 Mon Sep 17 00:00:00 2001
From: Paul Romano <paul.k.romano@gmail.com>
Date: Thu, 19 Apr 2018 11:07:27 -0500
Subject: [PATCH] Convert HDF5 attribute_exists to C++

---
 src/hdf5_interface.F90 | 16 +++++++++++-----
 src/hdf5_interface.cpp |  8 ++++++++
 src/hdf5_interface.h   |  1 +
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/hdf5_interface.F90 b/src/hdf5_interface.F90
index a0148cfd2d..eee5397671 100644
--- a/src/hdf5_interface.F90
+++ b/src/hdf5_interface.F90
@@ -332,7 +332,7 @@ contains
   end subroutine get_groups
 
 !===============================================================================
-! CHECK_ATTRIBUTE Checks to see if an attribute exists in the object
+! ATTRIBUTE_EXISTS checks to see if an attribute exists in the object
 !===============================================================================
 
   function attribute_exists(object_id, name) result(exists)
@@ -340,11 +340,17 @@ contains
     character(*),   intent(in) :: name ! name of group
     logical :: exists
 
-    integer :: hdf5_err ! HDF5 error code
-
-    ! Check if attribute exists
-    call h5aexists_by_name_f(object_id, '.', trim(name), exists, hdf5_err)
+    interface
+      function attribute_exists_c(obj_id, name) result(exists) &
+           bind(C, name='attribute_exists')
+        import HID_T, C_CHAR, C_BOOL
+        integer(HID_T), value :: obj_id
+        character(kind=C_CHAR), intent(in) :: name(*)
+        logical(C_BOOL) :: exists
+      end function attribute_exists_c
+    end interface
 
+    exists = attribute_exists_c(object_id, to_c_string(name))
   end function attribute_exists
 
 !===============================================================================
diff --git a/src/hdf5_interface.cpp b/src/hdf5_interface.cpp
index bf410923b6..aa44e7c972 100644
--- a/src/hdf5_interface.cpp
+++ b/src/hdf5_interface.cpp
@@ -11,6 +11,14 @@
 
 namespace openmc {
 
+bool
+attribute_exists(hid_t obj_id, const char* name)
+{
+  htri_t out = H5Aexists_by_name(obj_id, ".", name, H5P_DEFAULT);
+  return out > 0;
+}
+
+
 bool
 using_mpio_device(hid_t obj_id)
 {
diff --git a/src/hdf5_interface.h b/src/hdf5_interface.h
index fdaf9ac8fc..2e470dbc7d 100644
--- a/src/hdf5_interface.h
+++ b/src/hdf5_interface.h
@@ -12,6 +12,7 @@
 
 namespace openmc {
 
+extern "C" bool attribute_exists(hid_t obj_id, const char* name);
 extern "C" hid_t create_group(hid_t parent_id, const char* name);
 hid_t create_group(hid_t parent_id, const std::string& name);
 extern "C" void close_dataset(hid_t dataset_id);