Handle empty string input for parseBase64Binary instead of throwing IllegalArgumentException (#309)

* Handle empty string input for parseBase64Binary

* Fix input validation in _parseBase64Binary and add test cases from https://www.rfc-editor.org/rfc/rfc4648#section-10

Co-authored-by: Antonio Santos Izaguirre <[email protected]>

---------

Co-authored-by: Sander Hestvik <[email protected]>
Co-authored-by: Antonio Santos Izaguirre <[email protected]>

Author: 3 people

api/src/main/java/jakarta/xml/bind/DatatypeConverterImpl.java

@@ -711,10 +711,10 @@ private static int guessLength(String text) {
      *      because JIT can inline a lot of string access (with data of 1K chars, it was twice as fast)
      */
     public static byte[] _parseBase64Binary(String text) {
-        final int buflen = guessLength(text);
-        if (buflen < 3) {
+        if (null == text || text.length() % 4 != 0) {
             throw new IllegalArgumentException("base64 text invalid.");
         }
+        final int buflen = guessLength(text);
         final byte[] out = new byte[buflen];
         int o = 0;
 

api/src/test/java/org/eclipse/jaxb/api/DatatypeConverterTest.java

@@ -84,6 +84,15 @@ public void testPrint() {
     @Test
     public void testBase64() {
         Assert.assertThrows(IllegalArgumentException.class, () -> DatatypeConverter.parseBase64Binary("Qxx=="));
+
+        Assert.assertEquals("", new String(DatatypeConverter.parseBase64Binary("")));
+        Assert.assertEquals("f", new String(DatatypeConverter.parseBase64Binary("Zg==")));
+        Assert.assertEquals("fo", new String(DatatypeConverter.parseBase64Binary("Zm8=")));
+        Assert.assertEquals("foo", new String(DatatypeConverter.parseBase64Binary("Zm9v")));
+        Assert.assertEquals("foob", new String(DatatypeConverter.parseBase64Binary("Zm9vYg==")));
+        Assert.assertEquals("fooba", new String(DatatypeConverter.parseBase64Binary("Zm9vYmE=")));
+        Assert.assertEquals("foobar", new String(DatatypeConverter.parseBase64Binary("Zm9vYmFy")));
+
         Assert.assertNotEquals("Hello, world!", new String(DatatypeConverter.parseBase64Binary("SGVsbG8sIJdvcmxkIQ==")));
 
         Assert.assertEquals("Hello, world!", new String(DatatypeConverter.parseBase64Binary("SGVsbG8sIHdvcmxkIQ==")));