android: Add utility method to convert a byte array to a hex string

src/frontends/android/src/org/strongswan/android/utils/Utils.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2014 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+package org.strongswan.android.utils;
+
+
+public class Utils
+{
+	static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();
+
+	/**
+	 * Converts the given byte array to a hexadecimal string encoding.
+	 *
+	 * @param bytes byte array to convert
+	 * @return hex string
+	 */
+	public static String bytesToHex(byte[] bytes)
+	{
+		char[] hex = new char[bytes.length * 2];
+		for (int i = 0; i < bytes.length; i++)
+		{
+			int value = bytes[i];
+			hex[i*2]   = HEXDIGITS[(value & 0xf0) >> 4];
+			hex[i*2+1] = HEXDIGITS[ value & 0x0f];
+		}
+		return new String(hex);
+	}
+}