Fix radix encoder adding extra byte

Author: patrickfav

src/main/java/at/favre/lib/bytes/BinaryToTextEncoding.java

@@ -155,12 +155,23 @@ class BaseRadix implements EncoderDecoder {
 
         @Override
         public String encode(byte[] array, ByteOrder byteOrder) {
+            System.out.println("max length " + maxLength(array, radix));
             return new BigInteger(1, (byteOrder == ByteOrder.BIG_ENDIAN) ? array : Bytes.from(array).reverse().array()).toString(radix);
         }
 
         @Override
         public byte[] decode(String encoded) {
-            return new BigInteger(encoded, radix).toByteArray();
+            byte[] array = new BigInteger(encoded, radix).toByteArray();
+            if (array[0] == 0) {
+                byte[] tmp = new byte[array.length - 1];
+                System.arraycopy(array, 1, tmp, 0, tmp.length);
+                array = tmp;
+            }
+            return array;
+        }
+
+        private int maxLength(byte[] data, int radix) {
+            return BigInteger.valueOf(2).pow(BigInteger.valueOf(data.length).multiply(BigInteger.valueOf(8)).intValue()).toString(radix).length();
         }
     }
 }

src/test/java/at/favre/lib/bytes/BinaryToTextEncodingTest.java

@@ -26,8 +26,7 @@
 
 import java.nio.ByteOrder;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.*;
 
 public class BinaryToTextEncodingTest {
     @Test
@@ -50,7 +49,6 @@ public void encodeBaseRadix() throws Exception {
     }
 
     @Test
-    @Ignore
     public void encodeDecodeRadix() throws Exception {
         for (int i = 0; i < 32; i++) {
             Bytes rnd = Bytes.random(i);
@@ -62,10 +60,25 @@ public void encodeDecodeRadix() throws Exception {
                 System.out.println("radix" + j + ":\t" + encodedBigEndian);
                 System.out.println("orig   :\t" + rnd.encodeHex());
                 System.out.println("enc    :\t" + Bytes.wrap(decoded).encodeHex());
+                assertArrayEquals(rnd.array(), decoded);
             }
         }
     }
 
+    @Test
+    @Ignore("should fix")
+    public void encodeDecodeRadixZeros() throws Exception {
+        Bytes bytes = Bytes.wrap(new byte[]{0, 0, 0, 0});
+        BinaryToTextEncoding.EncoderDecoder encoding = new BinaryToTextEncoding.BaseRadix(36);
+        String encodedBigEndian = encoding.encode(bytes.array(), ByteOrder.BIG_ENDIAN);
+        byte[] decoded = encoding.decode(encodedBigEndian);
+
+        System.out.println("radix36:\t" + encodedBigEndian);
+        System.out.println("orig   :\t" + bytes.encodeHex());
+        System.out.println("enc    :\t" + Bytes.wrap(decoded).encodeHex());
+        assertArrayEquals(bytes.array(), decoded);
+    }
+
     @Test
     public void encodeDecodeBase64() throws Exception {
         for (int i = 4; i < 32; i += 4) {