From 5ad647c4637e80341574ee6631ead49bf13e0299 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 6 Feb 2019 14:01:21 +0100
Subject: boundary: add public functions for querying boundary information

Should allow treating boundaries in a generic manner.

API bump
---
 mg2d_boundary.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

(limited to 'mg2d_boundary.h')

diff --git a/mg2d_boundary.h b/mg2d_boundary.h
index 4a7dcee..12c897f 100644
--- a/mg2d_boundary.h
+++ b/mg2d_boundary.h
@@ -44,6 +44,10 @@ enum MG2DBCType {
  * Location of the boundary.
  */
 enum MG2DBoundaryLoc {
+    /**
+     * Undefined boundary location.
+     */
+    MG2D_BOUNDARY_NONE = -1,
     /**
      * coord0 lower
      */
@@ -94,4 +98,28 @@ typedef struct MG2DBoundary {
     MG2DBoundaryInternal *priv;
 } MG2DBoundary;
 
+/**
+ * @return index of the coordinate that is kept constant along this boundary
+ * (x: 0, y: 1)
+ */
+int mg2d_bnd_coord_idx(enum MG2DBoundaryLoc loc);
+
+/**
+ * @return 1 if this is the upper boundary, 0 for the lower one
+ */
+int mg2d_bnd_is_upper(enum MG2DBoundaryLoc loc);
+
+/**
+ * @return 1 if the corresponding variable increases in the direction from the
+ * computational domain across the boundary, -1 if it decreases.
+ *
+ * @note this is equivalent to (mg2d_bnd_is_upper(loc) ? 1 : -1)
+ */
+int mg2d_bnd_out_dir(enum MG2DBoundaryLoc loc);
+
+/**
+ * Construct the boundary id from coordinate and upper/lower specification.
+ */
+enum MG2DBoundaryLoc mg2d_bnd_id(int coord_idx, int is_upper);
+
 #endif // MG2D_BOUNDARY_H
-- 
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