#if !defined( COMMON_H )
#define COMMON_H
+/*
+ * Common macros.
+ * Copyright (C) 2018 Michael Goehler
+ *
+ * This file is part of mdp.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * type: bool variable stores only true or false.
+ *
+ * macro: MAX returns the higher one of two input variables
+ * macro: MIN returns the lower one of two input variables
+ *
+ */
+
+#if defined( __STDC__ ) // for standard C compiler
+#if __STDC_VERSION__ >= 199901L // for C99 and later
+#include <stdbool.h>
+#else // __STDC_VERSION__ >= 199901L
+#if !defined( bool )
+typedef enum {
+ false = 0,
+ true = 1
+} bool;
+#endif // !defined( bool )
+#endif // __STDC_VERSION__ >= 199901L
+#else // defined( __STDC__ )
+#define bool int
+#define true 1
+#define false 0
+#endif // defined( __STDC__ )
+
#define MAX(a, b) ({ typeof(a) _a = a; typeof(b) _b = b; _a > _b? _a : _b; })
#define MIN(a, b) ({ typeof(a) _a = a; typeof(b) _b = b; _a < _b? _a : _b; })
