added hex dump support

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@34828 71c3de6d-444a-0410-be80-ed276b4c234a

remoting/src/main/java/hudson/remoting/HexDump.java

+package hudson.remoting;
+
+/**
+ * @author Kohsuke Kawaguchi
+ */
+public class HexDump {
+    private static final String CODE = "0123456789abcdef";
+
+    public static String toHex(byte[] buf) {
+        return toHex(buf,0,buf.length);
+    }
+    public static String toHex(byte[] buf, int start, int len) {
+        StringBuilder r = new StringBuilder(len*2);
+        for (int i=0; i<len; i++) {
+            byte b = buf[start+i];
+            r.append(CODE.charAt((b>>4)&15));
+            r.append(CODE.charAt(b&15));
+        }
+        return r.toString();
+    }
+}

remoting/src/test/java/hudson/remoting/HexDumpTest.java

+package hudson.remoting;
+
+import junit.framework.TestCase;
+
+/**
+ * @author Kohsuke Kawaguchi
+ */
+public class HexDumpTest extends TestCase {
+    public  void test1() {
+        assertEquals("0001ff",HexDump.toHex(new byte[]{0,1,-1}));
+    }
+}