From b1343baa30875e80a377a9a4b842ef27f7b383a5 Mon Sep 17 00:00:00 2001
From: Grzegorz Kowal <grzegorz@amuncode.org>
Date: Wed, 2 Feb 2022 09:54:05 -0300
Subject: [PATCH] BOUNDARIES: Use enumerator for the boundary type.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
---
 sources/boundaries.F90 | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/sources/boundaries.F90 b/sources/boundaries.F90
index e5ff805..921e9e3 100644
--- a/sources/boundaries.F90
+++ b/sources/boundaries.F90
@@ -47,25 +47,27 @@ module boundaries
     end subroutine
   end interface
 
-! parameters corresponding to the boundary type
-!
-  integer, parameter            :: bnd_periodic   = 0
-  integer, parameter            :: bnd_open       = 1
-  integer, parameter            :: bnd_outflow    = 2
-  integer, parameter            :: bnd_reflective = 3
-  integer, parameter            :: bnd_gravity    = 4
-  integer, parameter            :: bnd_user       = 5
-
-! pointers to the custom boundary conditions, one per direction
+! pointers to custom boundary conditions, one per direction handling both sides
 !
   procedure(custom_boundary_iface), pointer, save :: &
-                                    custom_boundary_x => null(), &
-                                    custom_boundary_y => null(), &
-                                    custom_boundary_z => null()
+                                             custom_boundary_x => null(), &
+                                             custom_boundary_y => null(), &
+                                             custom_boundary_z => null()
 
-! variable to store boundary type flags
+! supported boundary types
 !
-  integer, dimension(3,2), save :: bnd_type       = bnd_periodic
+  enum, bind(c)
+    enumerator bnd_user
+    enumerator bnd_periodic
+    enumerator bnd_open
+    enumerator bnd_outflow
+    enumerator bnd_reflective
+    enumerator bnd_gravity
+  end enum
+
+! the boundary type array for both sides along all directions
+!
+  integer, dimension(3,2), save :: bnd_type = bnd_periodic
 
 #ifdef MPI
 ! arrays to store information about blocks which need to be exchange between
@@ -80,7 +82,6 @@ module boundaries
   public :: initialize_boundaries, finalize_boundaries, print_boundaries
   public :: boundary_variables, boundary_fluxes
   public :: custom_boundary_x, custom_boundary_y, custom_boundary_z
-  public :: bnd_type, bnd_periodic
 
 !- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 !