RFR: JDK-8007799 Base64.getEncoder(0, byte[]) returns encoder that unexpectedly inserts line separator when using some of the encoding methods

[Xueming Shen]

Thanks Mark for looking into this issue.

The change itself looks fine. Though I'm a little concerned whether
the performance cost (need to do an additional linemax > 0 check
inside the 'while" loop) is really worth it. Maybe an alternative is
to simply set the linemax to -1 if it's 0? such as

     public static Encoder getEncoder(int lineLength, byte[] lineSeparator) {
          Objects.requireNonNull(lineSeparator);
          int[] base64 = Decoder.fromBase64;
          for (byte b : lineSeparator) {
              if (base64[b & 0xff] != -1)
                  throw new IllegalArgumentException(
                      "Illegal base64 line separator character 0x" + Integer.toString(b, 16));
          }
          if (lineLength == 0)
              lineLength = -1;
          return new Encoder(false, lineSeparator, lineLength >> 2 << 2);
     }

And given it actually become a "normal" RFC4648 if the lineLength <=0, maybe
we should simply eliminate this "option" by changing the spec to say "throw
IAE if lineLength <=0", go use BAse64.getEncoder() if lineSeparator is not needed.

-Sherman


On 03/27/2013 09:01 AM, Mark Sheppard wrote:
> Hi,
>    please oblige and review the webrev below as a fix for the issue raised in JDK-8007799
>
> http://cr.openjdk.java.net/~msheppar/8007799/webrev.00/
>
> Description:
> "Specification for the method
> java.util.Base64.getEncoder(int lineLength, byte[] lineSeparator)
>
> says:
> Parameters:
>     lineLength - the length of each output line (rounded down to nearest multiple of 4). If lineLength <= 0 the output will not be separated in lines
>
> However if a zero line length is specified encoding methods wrap() and encode(ByteBuffer src, ByteBuffer dst, int bytesOut) return encoded string which starts from the given line separator. "
>
> the patch adds a check for linemax > 0 whenever a line separator might be added, and adds an new test case.
>
> regards
> Mark