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+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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 (see the file COPYING included with this
+ * distribution); if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef INTEGER_H
+#define INTEGER_H
+
+#include "error.h"
+
+/*
+ * min/max functions
+ */
+
+static inline int
+max_int (int x, int y)
+{
+ if (x > y)
+ return x;
+ else
+ return y;
+}
+
+static inline int
+min_int (int x, int y)
+{
+ if (x < y)
+ return x;
+ else
+ return y;
+}
+
+static inline int
+constrain_int (int x, int min, int max)
+{
+ if (min > max)
+ return min;
+ if (x < min)
+ return min;
+ else if (x > max)
+ return max;
+ else
+ return x;
+}
+
+/*
+ * Functions used for circular buffer index arithmetic.
+ */
+
+/*
+ * Return x - y on a circle of circumference mod by shortest path.
+ *
+ * 0 <= x < mod
+ * 0 <= y < mod
+ */
+static inline int
+modulo_subtract(int x, int y, int mod)
+{
+ const int d1 = x - y;
+ const int d2 = (x > y ? -mod : mod) + d1;
+ ASSERT (0 <= x && x < mod && 0 <= y && y < mod);
+ return abs(d1) > abs(d2) ? d2 : d1;
+}
+
+/*
+ * Return x + y on a circle of circumference mod.
+ *
+ * 0 <= x < mod
+ * -mod <= y <= mod
+ */
+static inline int
+modulo_add(int x, int y, int mod)
+{
+ int sum = x + y;
+ ASSERT (0 <= x && x < mod && -mod <= y && y <= mod);
+ if (sum >= mod)
+ sum -= mod;
+ if (sum < 0)
+ sum += mod;
+ return sum;
+}
+
+static inline int
+index_verify (int index, int size, const char *file, int line)
+{
+ if (index < 0 || index >= size)
+ msg (M_FATAL, "Assertion Failed: Array index=%d out of bounds for array size=%d in %s:%d",
+ index,
+ size,
+ file,
+ line);
+ return index;
+}
+
+#endif