Function enc&dec

src/crypto/Crypto.java

@@ -1,10 +1,111 @@
 package crypto;
 
-import java.util.Scanner;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
 
-public class Crypto {
-    public static void main(String[] args) {
-        Scanner scanner = new Scanner(System.in);
-	// write your code here
+interface ICrypto
+{
+    byte[] encrypt(byte[] data, String key);
+    byte[] decrypt(byte[] data, String key);
+}
+
+class CryptoShift implements ICrypto
+{
+    @Override
+    public byte[] encrypt(byte[] data, String key) {
+
+        String text = "";
+        for (int i = 0; i < data.length; i++) {
+            text += (char)(data[i] + Integer.parseInt(key));
+        }
+        return text.getBytes();
+    }
+    @Override
+    public byte[] decrypt(byte[] data, String key) {
+
+        String text = "";
+        for (int i = 0; i < data.length; i++) {
+            text += (char)(data[i] - Integer.parseInt(key));
+        }
+        return text.getBytes();
+    }
+}
+
+class Crypter
+{
+    private ICrypto alg;
+
+    public Crypter(String alg) throws Exception
+    {
+        switch (alg.toLowerCase()) {
+            case "shift":
+                this.alg = new CryptoShift();
+                break;
+            default:
+                throw new Exception("Invalid algorithm");
+        }
+    }
+
+    public byte[] crypt(byte[] data, String key, String mode)
+    {
+        if (mode.toLowerCase().equals("enc"))
+            return alg.encrypt(data, key);
+        if (mode.toLowerCase().equals("dec"))
+            return alg.decrypt(data, key);
+        return null;
     }
+
 }
+
+
+public class Crypto  {
+    public static void main(String[] args) throws IOException, Exception {
+        String mode = "";
+        String filein = "";
+        String fileout = "";
+        String alg = "";
+        String key = "";
+        for (int i = 0; i < args.length; i++) {
+            switch (args[i])
+            {
+                case "-mode":
+                    if (i+1 < args.length)
+                        mode = args[i+1];
+                    break;
+                case "-key":
+                    if (i+1 < args.length)
+                        key = args[i+1];
+                    break;
+                case "-in":
+                    if (i+1 < args.length)
+                        filein = args[i+1];
+                    break;
+                case "-out":
+                    if (i+1 < args.length)
+                        fileout = args[i+1];
+                    break;
+                case "-alg":
+                    if (i+1 < args.length)
+                        alg = args[i+1];
+                    break;
+            }
+        }
+
+        if (mode.isEmpty()||filein.isEmpty()||fileout.isEmpty()||!new File(filein).exists()) return;
+
+        FileInputStream fi = new FileInputStream(filein);
+        FileOutputStream fo = new FileOutputStream(fileout);
+
+        byte[] data = new byte[fi.available()];
+        fi.read(data,0,fi.available());
+        Crypter cr = new Crypter(alg);
+        byte[] cryptodata = cr.crypt(data, key, mode);
+        if (cryptodata == null) System.out.println("Invalid mode");
+        fo.write(cryptodata);
+
+
+    }
+}
+