console updater for mage.client. almost ready to work

mage.updater.client/src/main/java/com/magefree/update/ChechsumHelper.java

@@ -0,0 +1,37 @@
+package com.magefree.update;
+
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.security.MessageDigest;
+
+public class ChechsumHelper {
+    public static byte[] createChecksum(String filename) throws
+            Exception
+    {
+        InputStream fis =  new FileInputStream(filename);
+
+        byte[] buffer = new byte[1024];
+        MessageDigest complete = MessageDigest.getInstance("SHA1");
+        int numRead;
+        do {
+            numRead = fis.read(buffer);
+            if (numRead > 0) {
+                complete.update(buffer, 0, numRead);
+            }
+        } while (numRead != -1);
+        fis.close();
+        return complete.digest();
+    }
+
+    // see this How-to for a faster way to convert
+    // a byte array to a HEX string
+    public static String getSHA1Checksum(String filename) throws Exception {
+        byte[] b = createChecksum(filename);
+        String result = "";
+        for (int i=0; i < b.length; i++) {
+            result +=
+                    Integer.toString( ( b[i] & 0xff ) + 0x100, 16).substring( 1 );
+        }
+        return result;
+    }
+}